Patients who have orthopedic injuries that involve open fractures (fractures that break the skin) should go to the emergency room. Patients who have other injuries besides orthopedic ones should also go to the emergency room. For all other types of orthopedic and sports injuries, our centers can be your best option.  Below are some of the common injuries we treat:

Knee Injuries

The knee is commonly injured during walking and running activities. Most knee injuries occur because of a sudden change in direction (pivoting, shifting, jumping) or a sudden force (stepping down from a curb or high surface, landing during a jump or fall). Most knee injuries can be seen at an orthopedic urgent care clinic. A physical examination and medical imaging studies are used to diagnose knee injuries and then come up with an appropriate treatment plan. Common knee injuries include sprains, strains, and tears (cartilage and ligament).

Shoulder Injuries

Because the shoulder is one of the most mobile joints in the body, it undergoes a tremendous amount of force and rotation each day.  When the ligaments and muscles of the shoulder are overused or overstressed, painful injuries can occur.  Many of the common shoulder injuries we see are rotator cuff tears, shoulder fractures, shoulder dislocations and injuries to the soft tissue and muscles of the shoulder.

Ankle Injuries

Ankle injuries are very common. The most common type of ankle injury is an ankle sprain. When the ankle is over inverted (the soles of the feet point inward) or over everted (the soles of the feet point outward), the ligaments that connect the bones of the ankle joint can be sprained. Ankle sprains are graded on an increasing severity scale of grades one to three (G1-G3). When ankle sprains are seen at an orthopedic urgent care clinic, they are diagnosed and treated appropriately. Additionally, specialists at a clinic can check to make sure the ankle is not fractured. If it is, it can be treated accordingly.

Wrist Injuries

Wrist injuries commonly occur because of landing on an outstretched arm during a fall. A wrist strain can be painful and cause swelling, bruising, and possible numbness. A wrist fracture can also cause these symptoms. The most common type of wrist fracture is a distal radius fracture, a fracture of the large forearm bone on its end closest to the wrist. Both wrist sprains and fractures can be seen and treated at an orthopedic urgent care clinic. However, it should be again noted that patients with open fractures should go to the emergency room rather.

Source: Orthoinfo from the American Academy of Orthopaedic Surgeons 

When an unexpected accident happens turn to Urgent Care at Orthopedic Associates of Lancaster. With immediate access to orthopedic specialists, quick evaluations and on-site x-rays and MRI's OAL is here for all of your orthopedic needs.  

OAL Lancaster
170 North Pointe Blvd.
Lancaster, PA 17601(717) 299-4871

Injuries in young athletes are on the rise, but elbow and shoulder injuries in children are on the verge of becoming an epidemic. Thousands of children are seen each year complaining of elbow or shoulder pain. Damage or tear to the ulnar collateral ligament (UCL) is the most common injury suffered and is often caused by pitchers throwing too much. This ligament is the main stabilizer of the elbow for the motions of pitching. When it becomes damaged, it can be difficult to repair and rehabilitate.

HOW IS AN ELBOW OR SHOULDER INJURY DIAGNOSED?
If a young athlete is throwing too hard, too much, too early, and without rest, a serious elbow or shoulder injury may be on the horizon. If the athlete complains of elbow or shoulder pain the day after throwing, or movement of the joint is painful or restricted compared to the opposite side, see a physician familiar with youth sports injuries immediately.

HOW CAN OVERUSE BASEBALL INJURIES BE PREVENTED?
Overuse injuries — especially those related to the UCL and shoulder—are preventable. Some tips to keep you in the game throughout your life include:

Hip Exercises to Ease Arthritis Pain: How Exercise Helps Your Hips, and 7 Daily Exercises to Try

Let’s get this important misconception out of the way: Done correctly, working out is not going to exacerbate your hip pain or make your arthritis worse. But not exercising can make your arthritis worse, which is why doctors recommend exercises as an important part of your arthritis treatment plan, whether you have osteoarthritis or an autoimmune, inflammatory form such as rheumatoid or psoriatic arthritis.

Here’s what’s happening in your hip when you have arthritis, and why exercising and moving more helps relieve pain and stiffness.

How Arthritis Affects Your Hips

The hip is a ball-and-socket joint — the “ball” is the top of your thigh bone, and it sits in a “socket” that’s formed by part of your pelvic bone. Slippery tissue called cartilage covers the bone surface and helps cushion the joint. “Cartilage creates a low-friction environment so you can move easily and without pain,” explains Wayne Johnson, MD, orthopedic surgeon and assistant clinical professor at the University of Oklahoma.

In osteoarthritis (OA), the cartilage in the hip joint gradually wears down, which over time leads to pain, stiffness, swelling, and lack of mobility, says Dr. Johnson, who is a fellow of the American Academy of Orthopaedic Surgeons. Everyday tasks — like bending over to tie a shoe, getting up from a chair, or going for a walk — become more challenging and painful. The lifetime risk of developing osteoarthritis of the hip is 25 percent.

With rheumatoid and other forms of inflammatory arthritis, the immune system mistakenly attacks a protective lining in your joint called the synovium, and destroys cartilage. Though RA tends to affect smaller joints first (such as those in your hands and feet), symptoms can spread to both your hips as the disease progresses.

How Exercise Helps Hip Arthritis

Think of your hip joint like a bicycle, says Dr. Johnson. The muscles around the hip are the strong, supporting frame of the bike. The joint — especially one with arthritis — is like the weaker, flimsier chain. A strong frame takes some of the stress off a weaker chain.

The same is true in your hip. “We lose muscle strength as we age,” explains Dr. Johnson. “And any excess weight puts even more stress on a joint that’s becoming weaker due to arthritis.”

Exercise, then, helps strengthen the muscles that support your hip, which takes some of the load off on the worn-out, weaker joint. “That shift can translate to a decrease in pain and stiffness, easier motion and improved flexibility,” he says.

Exercise also help enhance balance, boost energy, improve sleep, and control weight. And in people with mild to moderate hip OA, a study published in Annals of the Rheumatic Diseases found those who exercised for one hour at least twice a week for 12 weeks were 44 percent less likely to need hip replacement surgery six years later, compared with those who did not exercise.

The types of exercise that can help ease arthritis pain may include:

• Range-of-motion and stretching exercises (to help maintain and improve flexibility)
• Strengthening exercises (to work your muscles a little harder)
• Aerobic exercise, like swimming or biking (to improve cardiovascular health and control your weight)
• Other activities like yoga and tai chi or even gardening and walking the dog.

Precautions to Keep in Mind Before Exercising with Hip Arthritis

If you’re new to exercise, it’s always smart to first talk to your doctor. “It’s important to consider the current limits of your joints, and work within those limits,” explains Lauren Shroyer, MS, director of product development at the American Council on Exercise. Your doctor or physical therapist can make sure the exercises are safe for you and help you gain strength, without exacerbating inflammation or aggravating joint pain, she says. Likewise, if you’ve had surgery on your hip, get guidance from your doctor or physical therapist on what hip exercises are safe for you.

More tips to help protect your joints:

Start slowly. Ease your joints into exercise if you haven’t been active for a while, say experts. Push too hard too fast, and you can overwork your muscles and worsen joint pain. Go easy at first, then increase the length and intensity of your work out as you progress.

Move gently. Warm up your muscles with five to 10 minutes of stretching at the start of every exercise activity, says Dr. Johnson; and do it again at the end. Don’t force any stretches; keep your movements slow and easy. With strength training, begin with fewer reps or lower weight, and build up gradually.

Stop if your hip (or anything else) hurts. “Listen to the pain,” says Shroyer. Take a break when your joints start to ache; or you feel any new joint pain, it’s time to stop. Talk to your doctor about what pain is normal and when it’s a sign of something more serious.

Stretch every day. If you have a flare of RA or an increase in OA pain, you should still stay active, says Dr. Johnson. Some simple stretching may diminish some of the pain.

Exercises to Help Relieve Hip Arthritis Pain

The following hip exercises were recommended by Shroyer at ACE and Dr. Johnson from the AAOS:

Hip Exercise: Clock Tap

Improves balance and stability, and strengthens muscles in your hips and legs

• Stand next to a wall or door frame for support.
• Balance on right foot; hold on to wall or door frame to stay steady, if needed. Keep your knee straight over your ankle, with a slight bend.
• Tap your left foot around your right foot, as if your right foot is the centerpiece on a clock, and your left is touching numbers on a clockface. Start at 12 o’clock, then tap at 11, 10, and 9.
• Retrace the numbers back to 12; then tap 1 and 2, and retrace back to 12.
• Repeat the sequence four times; then complete with the opposite foot.

Tip: Stay within a comfortable and stable range of motion when tapping “around the clock,” says Shroyer. If your knee starts to shift over as you tap for the 9 spot, you may be past your range. As you get stronger, you may be able to reach further on each side.

Hip Exercise: Standing Iliotibial Band Stretch

Stretches the outside of your hip

• Stand next to a wall for support.
• Cross the leg that is closest to the wall behind your other leg.
• Lean your hip toward the wall until you feel a stretch at the outside of your hip. Hold the stretch for 30 seconds.
• Cross the leg that is further from the wall behind your other leg.
• Repeat on the opposite side; then repeat the entire sequence four times.

Tip: Don’t lean forward or twist at the waist.

Hip Exercise: Knee to Chest

Stretches your buttocks

• Lie on your back on the floor with your legs extended straight out.
• Bend one knee and grasp your shinbone with your hands.
• Gently pull your knee toward your chest as far as you’re comfortable.
• Hold the stretch for 30 seconds and then relax for 30 seconds.
• Repeat on the other side, then pull both legs in together. Repeat the entire sequence four times.

Tip: Keep your lower back pressed into the floor.

Hip Exercise: Hamstring Stretch

Stretches the back of your thigh and behind your knee

• Lie on the floor with both knees bent.
• Lift one leg off of the floor and bring the knee toward your chest. Clasp your hands behind your thigh below your knee.
• Straighten your leg and then pull it gently toward your head until you feel a stretch. (If you can’t clasp your hands behind your leg, loop a towel around your thigh. Grasp the ends of the towel and pull your leg toward you.)
• Hold for 30 seconds and then relax for 30 seconds.
• Repeat on the other side; then repeat the entire sequence four times.

Tip: Don’t pull at your knee joint.

Hip Exercise: Hip Extension

Strengthens your buttocks

• Lie on your stomach on a firm, flat surface with a pillow under your hips. Keep your head, neck, and upper body relaxed.
• Bend one knee 90°.
• Lift your leg straight up.
• Slowly lower your leg down to the floor, counting to 5.
• Do 8 reps; then complete the exercise on the other side.

Tip: Begin with 8 reps, using only your body weight; and progress to 12, recommends Dr. Johnson. When that becomes easier, add ankle weights in one-pound increments. Each time you increase the weight, start again at 8 reps, working back up to 12.

Hip Exercise: Sit-and-Stand

Increases mobility and strengthens leg, core, and back muscles

• Stand in front of sturdy chair that won’t move, feet planted on the floor about hip-distance apart.
• Press your hips back and bend your knees a little to lower yourself into a seated position.
• Then tip forward from the hips, push through your feet and up with your legs to a standing position.
• Repeat the sequence 3 times.

Tip: Gradually build up to 5 or 10 reps, says Shroyer: “Sitting and standing is essential movement pattern you want to stay strong in.”

Hip Exercise: Bodyweight Squat

Progression from the sit-and stand to help strengthen thighs and buttocks

• Stand with your feet shoulder-distance apart, or a little wider. If needed, hold on to something stable, like the back of sturdy chair or kitchen sink.
• Keep your chest lifted and shift your weight back into your heels while slowly pushing your hips back, as is you were sitting down into a chair.
• Keep your feet flat and lower yourself as far as you’re comfortable (such as a quarter or halfway down to where a chair would be).
• Push through your heels and bring your body back up to standing.
• Repeat the sequence 3 times; gradually build up to more reps.

Tip: Keeping your feet a little wider than shoulder-distance apart is better for balance when you are struggling with hip pain, says Shroyer.

Source: creakyjoints.org; Teresa Dumanin

When an unexpected accident happens turn to Urgent Care at Orthopedic Associates of Lancaster. With immediate access to orthopedic specialists, quick evaluations and on-site x-rays and MRI's OAL is here for all of your orthopedic needs.

Cold Weather Exposure & Frostbite

During winter, it is always important to cover exposed skin when you are working outdoors, participating in winter sports, or running errands. Frostbite can happen in just minutes when you are outside in extreme cold—and can also occur in temperatures that are above freezing if there is strong wind.

Description

When you are out in the cold, your body's first priority is to maintain its core (optimal) temperature. To do that, it shifts blood away from your extremities, such as your hands and feet, and toward the central organs of your body—the heart and lungs. This is your body's way of ensuring that blood flows to the organs that need it most. This redirection of blood, however, increases the risk of localized injury from cold to your fingers, toes, or other extremities.

Body tissues actually freeze when they are frostbitten. Ice crystals form in the cells, causing physical damage and permanent changes in cell chemistry. When the ice thaws, additional changes occur that may result in cell death.

There are two degrees of frostbite:

• Superficial frostbite occurs if only the skin surface is affected.
• Deep frostbite affects the underlying tissues, as well.

Cause

Frostbite is caused by exposure to very cold temperatures. The elderly and the young are particularly susceptible to frostbite. Other risk factors include:

• Not dressing properly for the weather, staying out in the cold too long, or getting wet while you are exposed to the cold.
• Having a medical condition that affects your circulation, such as diabetes and atherosclerosis.
• Having had a previous injury that was caused by the cold.
• Taking certain drugs, including alcohol and nicotine, or medications such as beta-blockers—which decrease the flow of blood to the skin.

Symptoms

It is important to recognize the signs of frostbite so that you can seek medical help, if needed. Symptoms include:

• The affected area becomes numb.
• The skin may feel frozen, but deeper tissues are soft (superficial frostbite) or the entire affected area feels solid, hard and frozen (deep frostbite).
• The skin may appear waxy, white, or grayish.

Treatment

Prevention

It is easier to prevent frostbite than it is to treat it. If you must go out in the bitter cold, be prepared.

Observing the five commonsense precautions below will help ensure that your winter outings end safely:

1. Dress appropriately.
   Light, loose, layered clothing provides both ventilation and insulation. Top off your outfit with a water-repellent (not waterproof) fabric.
2. Protect your head, hands, and feet.
   Substantial heat loss occurs through the scalp, so a warm hat is vital. Mittens are warmer than gloves, and two pair of socks (wool over lightweight cotton) will help keep your feet warm.
3. Do not drink alcohol or smoke before going out into the cold.
   Alcohol, caffeine, and nicotine leave the skin more prone to thermal injury.
4. If you get wet, get inside!
   Remove wet clothing as quickly as possible.
5. Check yourself every half hour or so for signs of frostbite.
   If your fingers, toes, nose, ears or any other body parts feel numb, go inside immediately.
   
   

   Source: Orthoinfo from the American Academy of Orthopaedic Surgeons 

   When an unexpected accident happens turn to Urgent Care at Orthopedic Associates of Lancaster. With immediate access to orthopedic specialists, quick evaluations and on-site x-rays and MRI's OAL is here for all of your orthopedic needs.

   Monday through Friday
   No Appointment Necessary
   7:30 a.m. to 4:30 p.m.

   OAL Lancaster
   170 North Pointe Blvd.
   Lancaster, PA 17601
   (717) 299-4871

Back pain is common during pregnancy. Usually, the pain diminishes within a few weeks after delivery. But back pain may return as you begin lifting and carrying your infant on a daily basis. As your baby grows, the weight load increases and back pain can result.

Caring for an infant puts stress on your back. Lifting your baby can be especially hard on your spine. Initially, you may be lifting the 7- to 10-pound baby up to 50 times a day. By the time your child is a year old, you are lifting and carrying 17 pounds. Two years later, you will be lifting a 25- to 30-pound child.

In addition, many new parents spend a lot of time bending over their babies and holding that position for long periods of time.

Fortunately, there are many things you can do to prevent back problems, such as modifying your activities and exercising to strengthen your spine. 

General Conditioning

• Speak with your obstetrician about when you can start exercising again and what kinds of exercises are safe for you to do. Discuss what goals would be realistic in terms of returning to your pre-pregnancy weight and activity level. This will vary greatly depending on how easy or difficult your pregnancy and/or delivery were. If you had a Caesarian-section (C-section) delivery, it may take longer before you can begin exercising.
• When you are "cleared" for exercise, begin trying to restore your hip and back flexibility with stretching exercises or light yoga. Your baby's nap time is often a good opportunity for exercise. Because the risk of back pain is high among young, overweight women, getting back to exercise is especially important after pregnancy.
• If you are able to find a babysitter, participating in a group exercise class can be more interesting than exercising alone and can help ensure that your workout is safe and balanced.  Core muscles weaken during pregnancy and after a C-section delivery; taking a yoga or pilates class can help strengthen these muscles and may help prevent or reduce back pain.

Lifting Your Baby

• To pick up a child from the floor, bend at your knees — not at your waist. Squat down, tighten your stomach muscles and lift with your legs.
• Do not stretch your arms out to pick up your baby. Bring your baby close to your chest before lifting. Avoid twisting your body while holding your baby. 

Feeding Your Baby

• To avoid upper back pain caused by breastfeeding, do not bend over your baby to breastfeed. Bring your baby to your breast. A pillow or two placed on your lap will help bring your baby up to you.
• While you are nursing, sit in an upright chair rather than a soft couch.
• Remove the high chair tray when you are trying to put the baby in or take the baby out of the high chair. 

Carrying and Traveling With Your Baby

• Consider using a "front pack" to carry your baby when you are walking.
• Do not carry your child on your hip. This overloads the back muscles.
• Do not stand outside the car and try to place your child in the car seat. Kneel on the back seat as you place your baby into the car seat. Because the safest place for a child's car seat is in the middle of the backseat, you can sit next to the car seat while you place the child into the seat. 
• Infant car seats are heavy, and they get heavier as your infant grows. Rather than carrying your infant in the car seat, consider fastening the seat into place in the car first, then bring your baby outside separately and strap him or her into the seat. 
  

Source: Orthoinfo from the American Academy of Orthopaedic Surgeons

When an unexpected accident happens turn to Urgent Care at Orthopedic Associates of Lancaster. With immediate access to orthopedic specialists, quick evaluations and on-site x-rays and MRI's OAL is here for all of your orthopedic needs.

Distracted driving can cause crashes, injuries, and even death; it's a prevalent public issue that the American Academy of Orthopaedic Surgeons (AAOS) continues to champion. But what about distracted walking? What are the consequences of pedestrians talking on the phone, texting, listening to music, or engaging deeply in conversation with the person next to them?

"Today, more and more people are falling down stairs, tripping over curbs and other streetscapes and, in many instances, stepping into traffic, causing cuts, bruises, sprains, and fractures," said Alan Hilibrand, MD, chair of the AAOS Communications Cabinet. "In fact, the number of injuries to pedestrians using their phones has more than doubled since 2004, and surveys have shown that 60% of pedestrians are distracted by other activities while walking."

In 2009, AAOS launched the "Decide to Drive" campaign to educate children, teens and adults about the dangers of distracted driving.

More recently, AAOS expanded its injury-prevention efforts to include distracted walking. The "Digital Deadwalkers" radio and television public service announcements (PSAs) distributed in 2015 and 2016 humorously, but effectively, highlight what can happen when pedestrians focus on anything or anyone other than the task of safely getting where they need to go.

AAOS Study on the Perceptions and Behaviors Associated with Distracted Walking

To learn more about the perceptions and behaviors associated with distracted walking, AAOS commissioned a Distracted Walking Study in 2015. The study involved 2,000 respondents nationally, and another 500 respondents in each of the following eight cities: New York, Los Angeles, Chicago, Philadelphia, Houston, Phoenix, Atlanta and Seattle.

First, while 78% of U.S. adults believe that distracted walking is a "serious" issue; three-quarters of Americans say it's "other people" who walk distracted. Only 29% of respondents admit that they, personally, have an issue.

And the sense of "it's not me, it's you" cuts across a range of distracted walking behaviors:

Despite the obvious risks associated with distracted walking, as many respondents believe it is "embarrassing (in a silly way)" as feel it is "dangerous" (46%). Furthermore, 31% say distracted walking is "something I'm likely to do" and 22% think distracted walking is "funny," according to the study.

And distracted walking is resulting in injuries. Nearly 4 out of 10 Americans say they have personally witnessed a distracted walking incident, and just over a quarter (26%) say they have been in an incident themselves.

In addition:

• Of those injured in a distracted walking incident, women aged 55 and over are most likely to suffer serious injuries, while Millennials (ages 18 to 34) are least likely to be injured, according to the survey, despite the younger age group reporting higher rates of distracted walking incidents.
• Perceptions of distracted walking also differ by generation, with 70% of Millennials believing that distracted walking is a serious issue compared with 81% of individuals aged 35 and older.
• Millennials are more likely to engage in common distracted walking behaviors: texting, listening to music, and talking on the phone.
• Half of Millennials think distracted walking is "embarrassing--in a funny way."

• Can We Walk and Talk at the Same Time?

  One of the challenges in combatting distracted walking may be that many Americans are overly confident in their ability to multitask.

  When asked why they walk distracted, 48% of respondents say "they just don't think about it," 28% feel "they can walk and do other things," and 22% "are busy and want to use their time productively."

  Among distracted walking behaviors, 75% of respondents say they personally "usually/always" or "sometimes" have "active conversations" with another person they are walking with--making this the most common distracted walking behavior people admit to doing themselves.

  Perceptions Vary by City and Region

  Your perception of the issue may depend slightly on where you live. For example:

  • Among the eight markets, New York City residents were most likely to view distracted walking as a serious issue (86%), and Seattle residents were least likely to view the issue as serious (77%).
  • New Yorkers were more likely to say they personally walk distracted (39%) than were walkers living in the other cities.
  • Residents of Chicago and Philadelphia were most likely to see distracted walking as "dangerous" (49%), while those in Houston were the least likely to think it's dangerous (40%).

Other Distracted Walking Statistics

Other research studies highlight the many dangers of distracted walking:

• Typing (texting) or reading a text alters a pedestrian's gait, speed, and walking pattern, according to a recent study.
• Teens and young adults, ages 16 to 25, were most likely to be injured as distracted pedestrians, and most were hurt while talking rather than texting: Talking on the phone accounted for 69% of injuries between 2004 and 2010. Texting accounted for 9% of injuries during the same period.
• Distracted pedestrians may have been a contributing factor in the 4,200 pedestrian deaths and 70,000 injuries in traffic crashes in 2010, according to the National Highway Transportation Safety Administration.
• A recent study observed nearly one-third of pedestrians at 20 high-risk intersections in Seattle listening to music, texting, or using a cellphone. Those who texted took almost two seconds, or 18% longer, to cross the intersection compared with those who weren't distracted. Those who texted were four times more likely to display at least one "unsafe crossing behavior," such as ignoring traffic signals or failing to look both ways.
• In a recent study that looked at headphones and pedestrian distraction, of 116 reported deaths involving pedestrians wearing headphones, 68% were male and 67% were under the age of 30. The majority of vehicles involved in the crashes were trains (55%), and 89% of the incidents occurred in urban areas. Seventy-four percent of case reports stated that the victim was wearing headphones at the time of the crash. 

Safety Tips

To be safe and alert when walking, keep in mind these important tips:

• If you must use headphones or other electronic devices, maintain a volume where you can still hear the sounds of traffic and your surroundings.
• If you need to talk to a child or the person next to you, make a phone call, text or other action that could distract you from the goal of getting where you need to go safely, stop and do so away from the pedestrian traffic flow.
• While you walk, focus on the people, objects, and obstacles around you.
• Don't jaywalk. Cross streets carefully, preferably at a traffic light, remaining cognizant of the pedestrian traffic flow and the cars and bikes in and near the road.
• Look up, not down, especially when stepping off or onto curbs or in the middle of major intersections; and/or when walking or approaching on stairs or escalators.
• Stay alert in mall and other parking lots, and on and near streets, especially during the winter months when it gets dark earlier and drivers are not as likely to see you

When an unexpected accident happens turn to Urgent Care at Orthopedic Associates of Lancaster. With immediate access to orthopedic specialists, quick evaluations and on-site x-rays and MRI's OAL is here for all of your orthopedic needs.

The speedy, bumpy, sometimes scary slide downhill is one of the outdoor winter activities that youths and adults have always enjoyed. It can be fun, but every year thousands of youths and adults are injured sledding down hills in city parks, streets and resort areas. Most of these injuries are preventable.

Incidence of Injury
According to the U.S. Consumer Product Safety Commission, there were more than 52,000 sledding, snow tubing, and tobogganing-related injuries treated at hospital emergency rooms, doctors' offices and clinics in 2014. The total medical, legal and liability, pain and suffering, and work loss-related costs were close to $2 billion.

The majority of injuries happen to youths age 14 and younger, especially in the run outs at the end of the sledding path. Adult supervision is needed to make sure that children sledding down a hill don't collide with children in the run outs and that the end of the sledding path isn't in a street or parking lot, pond or other hazardous area. Some of the injuries can be serious enough to cause lifelong disability or death. When a sled hits a fixed object such as a tree, rock or fence, the rider may suffer head and neck injuries. Helmets help prevent head injuries and should be worn by sledders under 12 years old.

Young children are very vulnerable to injuries. They have proportionally larger heads and higher centers of gravity than older children and teens. Their coordination has not fully developed and they can have difficulty avoiding falls and obstacles.

Do Not Sled on Public Streets
The first big snowfall of the winter season often tempts youths to sled down sloping streets where they may be hit by cars and trucks or slam into parked vehicles, curbs, and fences.

Speeding down hills in parks that are not designed for sledding is risky. Individuals may have to dodge trees and rocks.

Sit in a Forward-Facing Position
Some youths may run with their sleds and leap forward in a "belly flop" that does not give them control of where they are sliding.

Do not sled on plastic sheets. They cannot be steered and can be pierced by sharp objects.

Essential Precautions

• Sledding should be done only in designated and approved areas where there are no trees, posts, fences or other obstacles in the sledding path. The sledding run must not end in a street, drop off, parking lot, pond or other hazard.
• Parents or adults must supervise children in sledding areas to make sure the sledding path is safe and there are not too many sledders on the hill at the same time or at the end of the run to avoid collisions.
• No one should sled headfirst. All participants should sit in a forward-facing position, steering with their feet or a rope tied to the steering handles of the sled.

Preferred Precautions

• Young children should wear a fitted helmet while sledding.
• The sled should have runners and a steering mechanism, which is safer than toboggans or snow disks.
• Sledding in the evening should only be done in well-lighted areas.
• Plastic sheets or other materials that can be pierced by objects on the ground should not be used for sledding.
• Sledders should wear layers of clothing for protection from injuries and cold.
  
  Source: American Academy of Orthopaedic Surgeons 

When an unexpected accident happens turn to Urgent Care at Orthopedic Associates of Lancaster. With immediate access to orthopedic specialists, quick evaluations and on-site x-rays and MRI's OAL is here for all of your orthopedic needs.

Common Basketball Injuries

The fast-paced action of basketball can cause a wide range of injuries, most often to the foot, ankle, and knee. Sprained ankles and knee ligament tears are common. Basketball players are also at risk for jammed fingers and stress fractures in the foot and lower leg.

Several strategies can help to prevent basketball injuries — from careful inspection of the play area to using proper passing techniques.

Proper Preparation for Play

Maintain fitness. Be sure you are in good physical condition at the start of basketball season. During the off-season, stick to a balanced fitness program that incorporates aerobic exercise, strength training, and flexibility. If you are out of shape at the start of the season, gradually increase your activity level and slowly build back up to a higher fitness level.

Warm up and stretch. Always take time to warm up and stretch. Research studies have shown that cold muscles are more prone to injury. Warm up with jumping jacks, stationary cycling or running or walking in place for 3 to 5 minutes. Then slowly and gently stretch, holding each stretch for 30 seconds.

Hydrate. Even mild levels of dehydration can hurt athletic performance. If you have not had enough fluids, your body will not be able to effectively cool itself through sweat and evaporation. A general recommendation is to drink 24 ounces of non-caffeinated fluid 2 hours before exercise. Drinking an additional 8 ounces of water or sports drink right before exercise is also helpful. While you are exercising, break for an 8 oz. cup of water every 20 minutes.

Focus on Technique

• Play only your position and know where other players are on the court to reduce the chance of collisions.
• Do not hold, block, push, charge, or trip opponents.
• Use proper techniques for passing and scoring.
• Do not forget sportsmanship.

Ensure Appropriate Equipment

• Select basketball shoes that fit snugly, offer support, and are non-skid.
• Ankle supports can reduce the incidence of ankle sprains.
• Protective knee and elbow pads will protect you from bruises and abrasions.
• Use a mouth guard to protect your teeth and mouth.
• If you wear glasses, use safety glasses or glass guards to protect your eyes.
• Do not wear jewelry or chew gum during practice or games.

Ensure a Safe Environment
• Outdoor courts should be free of rocks, holes, and other hazards. Inside courts should be clean, free of debris, and have good traction.
• When playing outside, environmental conditions must be considered. Players should avoid playing in extreme weather or on courts that are not properly lighted in the evening.
• Baskets and boundary lines should not be too close to walls, bleachers, water fountains, or other structures. Basket goal posts, as well as the walls behind them, should be padded.

Prepare for Injuries
• Coaches should be knowledgeable about first aid and be able to administer it for minor injuries, such as facial cuts, bruises, or minor strains and sprains.
• Be prepared for emergencies. All coaches should have a plan to reach medical personnel for help with more significant injuries such as concussions, dislocations, contusions, sprains, abrasions, and fractures.

Safe Return to Play
• An injured player's symptoms must be completely gone before returning to play. For example:
• In case of a joint problem, the player must have no pain, no swelling, full range of motion, and normal strength.
• In case of concussion, the player must have no symptoms at rest or with exercise, and should be cleared by the appropriate medical provider.

Because many young athletes are focusing on just one sport and are training year-round, doctors are seeing an increase in overuse injuries. The American Academy of Orthopaedic Surgeons has partnered with STOP Sports Injuries to help educate parents, coaches, and athletes about how to prevent overuse injuries. 

Specific tips to prevent overuse injuries include:
• Limit the number of teams in which your child is playing in one season. Kids who play on more than one team are especially at risk for overuse injuries.
• Do not allow your child to play one sport year round — taking regular breaks and playing other sports is essential to skill development and injury prevention.

Source: US Consumer Product Safety Commission (CPSC), 2009
https://www.orthoinfo.org/en/staying-healthy/basketball-injury-prevention/

by Gregory A. Tocks, D.O. 

Orthopedic Associates of Lancaster Ltd.

INTRODUCTION

Since long-term survivors are at risk of needing a revision procedure, the durability of their prostheses, particularly at the bearing surfaces, is a major concern. Because of the stresses at the hip joint, the ideal component should minimize wear, maintain stability, and preserve longevity. This article provides an outline of the common prosthetic bearing surfaces for total hip replacement, their comparative wear characteristics, advantages, and disadvantages. 

The techniques of hip surgery are not the focus of this article, but for the interested reader, the common surgical approaches and methods of hip arthroplasty are illustrated on the websites of one of the prosthesis manufacturers.3

PROBLEM OF WEAR IN POLYETHYLENE ACETABULAR LINERS

Fig. 1 Illustration of pink ceramic femoral head, white polyethylene liner, and metal acetabular cup. The femoral stem prosthesis is not shown. (From Depuy Pinnacle Polyethylene technique guide.3).  

Fig. 2 A: Acetabular cup with cobalt-chromium femoral head and highly crossed-linked polyethylene liner; B: Acetabular cup with ceramic femoral head and highly crossed-linked polyethylene liner; C: Acetabular cup with ceramic femoral head and ceramic liner.

The acetabular liner is a polyethylene implant that is generally impacted into the acetabular cup. During the life of a total hip arthroplasty, wear primarily affects the polyethylene acetabular liner. The

Consequences of Wear

The wearing process in polyethylene liners produces small particles of polyethylene debris. The immune system responds by releasing macrophages and associated cytokines (e.g. TNF-α), which activate osteoclasts that produce osteolysis around the hip joint (Fig. 3).

 

Fig. 3. CT scan coronal (A) and axial (B) images showing significant osteolysis behind the previously implanted acetabular cup. 

The loss of bone causes micromotion of the hip implants, and further potentiates osteolysis. As a result of the osteolysis and wear, patients are at increased risk of several consequences, including periprosthetic fractures from simple falls or minor trauma, aseptic loosening of the prosthesis, or dislocation of the prosthesis.

Conventional Polyethylene and Highly Crossed-Linked Polyethylene

The polyethylene component has gone through two generations, termed “conventional polyethylene,” (CP) and “highly crossed-linked polyethylene” (XPE). In CP, radiation is used to form the hydrocarbon bonds, and the irradiation produces free radicals. If oxygen binds at the site of free radical formation, the resulting oxidation degrades the material’s properties. CP is irradiated with doses of 25-40 kGy,* and XPE is irradiated with doses of 50-100 kGy. The higher dose increases the cross-linking potential between free radicals, but radiation doses greater than 100 kGy compromise the mechanical properties of the material. 

Another step in the process to reduce free radicals and oxidation is thermal stabilization, or heating. In the production of polyethylenes, various commercial companies use different types of radiation, radiation doses, and methods of stabilization, machining, and terminal sterilization. 

Wear is termed linear wear (femoral head penetration into the liner), and volumetric wear (amount of material lost). Linear wear is assessed in clinical studies, and volumetric wear in laboratory studies. Osteolysis has a higher propensity to occur with linear wear greater than 0.10 mm/yr and volumetric wear greater than 80 mm3/yr.4 Laboratory simulator studies done prior to commercial release demonstrated less wear for XPE compared with CP.5-11 Those in-vitro wear studies also demonstrated that with XPE, the degree of wear that occurs is not related to the size of the prosthetic femoral head selected, nor to the initial thickness of the polyethylene liner. (The importance of this characteristic will become clear in a discussion below.) 

XPE was introduced into clinical practice in 1999 with the expectation that lower wear rates in-vitro would translate to lower wear rates in vivo. Two randomized clinical studies followed patients for five years after total hip arthroplasties with XPE or CP.12 Both studies concluded that, compared with CP, XPE had significantly fewer penetrations of the liner by the femoral head. The wear rate for XPE decreased by more 95% compared with the wear rates for CP, and tended to plateau after one year. 

Another study found that five years after total hip arthroplasty there was significantly less osteolysis on CT scan with XPE compared with CP (28% versus 80%).13 Multiple other studies have since confirmed a reduction in wear rates for XPE compared with CP, which has translated into less osteolysis and aseptic loosening in total hip arthroplasties with XPE.

FEMORAL HEAD AND ACETABULAR LINER BEARINGS Cobalt-Chromium & Crossed Linked Polyethylene (XPE)

The most common femoral head composition used in total hip arthroplasty is made of a cobalt-chromium (CoCr) metal alloy. As a result, the most widely used combinations in the U.S. are metal-on-polyethylene bearings (Fig.3), and most studies that compared CP to XPE wear used CoCr femoral heads. In 2013, the Swedish registry detected a trend toward fewer cup/liner revisions with the use of XPE, compared with an increase in the previous years when CP was used.14 In 2014, the Australian arthroplasty registry also noted that, as time progressed, there was a lower revision rate with XPE compared with CP.15 

In high risk patients, larger femoral heads are used sometimes to decrease the risk of impingement of the femoral head or neck of the femoral prosthesis on the edge of the acetabulum or polyethylene liner. These contacts may produce a lever arm that causes a dislocation. To accommodate the larger femoral head, a thinner polyethylene liner would be needed, but as noted earlier, multiple studies have demonstrated that for XPE, thickness of the polyethylene liner does not affect the wear rate. A thinner XPE cup might also raise concern about fracture, but this also has not been an issue except in those acetabular cups placed more vertically, anteverted, or with a rim thickness at the locking mechanism < 4 mm.

Since most non-cemented femoral prostheses are constructed of titanium, there has been concern recently about the bearing coupling between the CoCr femoral head and the titanium femoral prosthesis. This mixed metal construct may increase the risk of fretting** and corrosion at the modular junction, a process termed trunnionosis (Fig. 4). (The trunnion is the tapered portion of the femoral stem prosthesis where the femoral head is impacted during implantation.)

 

Fig. 4 Example of trunnionosis of a cobalt chromium femoral head and the tapered portion of the femoral prosthesis. With CoCr femoral heads, there have been reports of corrosion at the trunnion, metal wear at the trunnion, and adverse local tissue reactions from the metal debris. As a result, it has been proposed that ceramic femoral heads be used to avoid these reactions. However, registries have not reflected a statistically significant difference in revision rates between ceramic or CoCr femoral heads with XPE liners. Also, ceramic femoral heads typically are significantly more expensive than CoCr femoral heads and may not be cost effective. 

Studies have also revealed that XPE liners are more tolerant of acetabular component malposition. Together with the low wear characteristics of XPE, the cheaper cost of CoCr femoral heads, and the ability of metal-on-XPE bearings to withstand minor malposition, CoCr-XPE bearings should be the predominant couple in current total hip arthroplasties.

Ceramic Bearings

Ceramic bearings were first used in clinical practice in the 1970s. The ceramic components are fabricated from pure alumina, zirconia, and alumina matrix composite powder. In total joint replacement, ceramic constructs are available for both the femoral head and the acetabular liner. Ceramic constructs have stronger mechanical properties and lower wear rates.16,17 Their hard structures and smoothly polished surfaces provide higher resistance to wear, and minimize frictional forces because of their hydrophilic properties.18

Not only do ceramic-on-ceramic constructs have the lowest wear rate amongst all bearings, but they also cause less soft tissue reactions when compared to metal-on-polyethylene and metal-on-metal bearings.19 Because a ceramic component is not a metal alloy, there is less trunnionosis with the combination of a ceramic femoral head and a titanium femoral prosthesis, and less chance for metal debris and damage to the titanium trunnion. Also, the lack of metal debris makes ceramic femoral heads beneficial in patients with metal hypersensitivity.

In-vivo studies have demonstrated excellent wear rates over a 10-year period for both ceramic-on-polyethylene,20-24 and ceramic-on-ceramic bearings,21-22,25-29 with no statistically significant difference in osteolysis, wear rates, or implant failure.22-24 

Nonetheless, first-generation ceramic components had higher rates of component fracture than XPE liners with CoCr femoral heads. Fracture is catastrophic because it results in multiple fragments that may lead to third body wear and damage of the femoral prosthesis. Fortunately, the newest generation of mixed oxide ceramic materials has greatly reduced the risk of fracture to roughly 0.003% and 0.03% for Delta ceramic heads and liners, respectively.30

The various factors that influence the risk of ceramic femoral head fractures include the cleanliness of the trunnion prior to head impaction, the amount of force used to impact the head on the trunnion, and the size and length of the femoral head. (Smaller heads and shorter necks have a higher risk of fracture.) 

Ceramic-on-ceramic hip constructs are also associated with increased squeaking. The Australian National Joint Registry noted a 4.2% rate of squeaking with this construct.31 Squeaking can occur with every step, or with deep flexion, and is likely caused by malposition of the acetabular component with excessive inclination and anteversion. Squeaking may also occur with the loss of the fluid film lubricating the joint. Component malposition is also a factor, as it may result in increased loading against the edge of the cup. Care must be taken to avoid this complication because it may produce embarrassment and anxiety for the patient, and litigation against the surgeon. There is no clear evidence that squeaking increases the wear rate of the implant, though there are suggestions that it may. In addition, ceramic heads have traditionally been significantly more expensive than CoCr, and their cost effectiveness is debatable.

Ceramicized Femoral Heads

Zirconium is a hard metal with properties like titanium. It is not found naturally as a metal, but can be refined, through a complex process, from zirconium silicate (ZrSiO4). However, Zirconium oxide (ZrO2) is not a metal but a ceramic. It was first used clinically in total hip arthroplasties in approximately 2003 as a zirconium oxide, ceramic, outer surface of approximately 5 μm on a zirconium metal femoral head (Fig. 5).

 

Fig. 5 Acetabular cup with highly crossed-linked polyethylene liner and ceramicized femoral head.

This ceramic outer surface has similar mechanical properties to a fully ceramic bearing, including a smooth surface, increased scratch resistance, and increased hardness when compared to CoCr. In vitro studies confirm that ceramicized zirconium femoral heads share the improved resistance to wear of fully ceramic heads with polyethylene, especially with XPE.32 The Australian Joint Registry reported a low revision rate of 3.3% at 11 years with this bearing couple.33 However, in-vivo studies vary when comparing XPE with CoCr or ceramicized heads. Some studies show statistically significant differences in wear rate, and others demonstrate no difference.34-36

Because of its zirconium alloy core, this composite will not fracture like fully ceramic heads. However, the oxide surface may be damaged if it contacts other metal surfaces, such as the rim of the acetabular metal shell during joint reductions and dislocations. Ceramicized femoral heads also have a higher resistance to fretting and corrosion of the trunnion compared to CoCr, so they may be a suitable option if there is concern about trunnionosis. 

Like ceramic heads, ceramicized heads are also a viable option in patients with metal hypersensitivity since they avoid metal debris and trunnionosis at the bearing junction. Like the all-ceramic heads, however, ceramicized heads are significantly more expensive than CoCr femoral heads. Also, only one company currently manufactures this product, and it should therefore only be used with this company’s compatible femoral prosthesis.

In sum, ceramicized heads are a good option because of their improved wear characteristics and good in-vivo results, but their increased cost, and production by only one manufacturer, limits their widespread use.

METAL-ON-METAL FEMORAL HEAD AND LINER

As discussed throughout this article, a primary concern in total hip replacements is the wear rates of bearing materials. A metal-on-metal (MoM) bearing includes a CoCr metal head and a metal acetabular liner. (Fig. 6)

 

Fig. 6. Metal-on-metal hip prosthesis with femoral stem, cobalt chromium femoral head, metal liner, and metal acetabular cup. 

Traditional stemmed MoM hip replacements (and later resurfacings) were first introduced in the 1990s because they offered lower wear rates. For younger patients who need total hip replacement for osteoarthritis, longevity of the implant is a particularly important characteristic. It is estimated that since 1996, more than 1 million MoM implants have been inserted worldwide. MoM bearings can result from traditional hip replacement with a stemmed femoral prosthesis (Fig. 7B), or resurfacing of the femoral head with a metal cap (Fig. 7A), in which case more bone is preserved.

 

Fig. 7. Radiographs of metal-on-metal prosthesis. A: Hip resurfacing prosthesis; B: Stemmed metal-on-metal total hip replacement.

The benefits of MoM bearings compared with metal-on-polyethylene include not only lower volumetric wear rates, but also greater stability of the implant; because metal inserts are thinner than polyethylene liners, larger femoral head sizes can be used. 

However, the use of MoM bearings in stemmed hip replacements is not recommended in the U.S. because there are reports in the literature of poor outcomes. When MoM bearings are inserted in patients who are more than 55 years old, have larger femoral heads, or have acetabular cups placed in excessive inclination, they have a higher risk of revision than polyethylene and ceramic bearings.36-38 

Soft tissue reactions from the metal ions of the MoM bearings are the key issues in failure of the implants and associated complications. The metal ions cause adverse local tissue reactions (ALTRs), osteolysis, enlarged bursae, effusions, creation of pseudotumors, destruction of the abductor muscles, and necrosis. (Fig. 8)

 

Fig. 8. A: MARS MRI axial image with pseudotumor (arrow) anterior to the femur and metal-on-metal prosthesis; B: Intraoperative image of previous metal-on-metal prosthesis causing extensive metallosis and soft tissue destruction.

A lymphocyte dominated immunologic response occurs in the tissue, known as aseptic lymphocyte-dominant vasculitis-associated lesions (ALVAL). Unfortunately, it is not possible to predict which patients will have these reactions to metal ions. Some patients have symptoms, others have none, but it is generally recommended that even asymptomatic patients should be evaluated yearly with radiographs to assess osteolysis and blood levels of cobalt and chromium ions. Metal ion levels > 7 ppb (parts per billion) are considered elevated, and should instigate advanced imaging. Metal artifact reduction sequence (MARS) MRI helps assess for presence of pseudotumors and integrity of the abductor and gluteal muscles.

Optimum treatment of asymptomatic patients is debated. Treatment of symptomatic patients is multi-factorial but commonly involves a revision total hip replacement. Placement of metal-on-polyethylene or ceramic-on-polyethylene bearing constructs are generally recommended for stable acetabular and femoral prostheses. 

Many companies have recalled their MoM stemmed hip replacements because of these unfavorable outcomes. Therefore, hip resurfacing is the only recommended MoM bearing, and should be reserved for younger patients with preserved femoral head bone stock. However, this operation is not typically performed by most orthopedic surgeons.

CONCLUSION

Substantial progress has been made in the bearing components of total hip replacements in the past 30 years. Newer highly crossed-link polyethylene liners have significantly decreased wear rates when compared with conventional polyethylene. Cobalt chromium femoral heads and highly crossed linked polyethylene liners are the dominant bearing couple used in the United States, due to excellent follow-up studies. Ceramic and ceramicized femoral heads have lower wear rates, but they are more costly. They may be viable options in younger patients, and those with metal hypersensitivities. Stemmed metal-on-metal hip replacements have largely been removed from the U.S. market due to post-operative complications, and the need for revision surgery. The ultimate goal will be to create a bearing couple with minimal complications and increased durability.* Gy = Gray, the International Unit of absorbed ionizing radiation. It is derived from the applied energy (in Joules) and the mass of the affected matter (in Kg). 

kGy = thousands of units. ** Fretting: A special wear process that occurs at the contact area between two materials under load that are subjected to relative motion by vibration or some other force.

REFERENCES

1. Wolford M, Palso K, Bercovitz A: Hospitalization for total hip replacement among inpatients aged 45 and over: United States, 2000-2010. Centers for Disease Control and Prevention https://www.cdc.gov/nchs/data/databriefs/db186.htm 

2. Kurtz S, Ong K, Lau E, et al: Projections of primary and revision hip and knee arthroplasty in the United States from 2005 to 2030. J Bone Joint Surg Am 2007;89(4):780-785. 

3. Depuy Pinnacle Polethylene technique guide: 

4. Hammerberg EM, Wan Z, Dastane M, et al: Wear and range of motion of different femoral head sizes. J Arthroplasty 2010;25(6):839-843. 

5. Estok DM II, Burrough BR, Muratoglu OK, et al: Comparison of hip simulator wear of 2 different highly crossed-linked ultra high molecular weight polyethylene acetabular components using both 32- and 38-mm femoral heads. J Arthroplasty 2007;22(4):581-589. 

6. Muratoglu OK, Rubash HE, Bragdon CR, et al: Simulated normal gait wear testing of a highly crossed-linked polyethylene tibial insert. J Arthroplasty 2007;22(3):435-444. 

7. Laurent MP, Johnson TS, Crowninshielf RD, et al: Characterization of a highly crossed-linked ultrahigh molecular-weight polyethylene in clinical use in total hip arthroplasty. J Arthroplasty 2008;23(5):751-761. 

8. Ito H, Maloney CM, Crowninshield RD, et al. In vivo femoral head damage and its effect on polyethylene wear. J Arthroplasty 2010; 25(2): 302-308. 9. Shen FW, Lu Z, McKellop HA: Wear versus thickness and other features of 5 MRAD crosslinked UHMWPE acetabular liners. Clin Orthop Relat Res 2011; 469(2): 395-404. 

10. McKellop H, Shen FW, DiMaio W, et al. Wear of gamma-crosslinked polyethylene acetabular cups against roughened femoral balls. Clin Orthop Relat Res 1999; 3369:73-82. 

11. McKellop HA, Shen FW, Lu B, et al. Effect of sterilization method and other modifications of the wear resistance of acetabular cups made of ultra-high molecular weight polyethylene: A hip simulator study. J Bone Joint Surg Am 2007;89 (10):2212-2217. 

12. Digas G, Karrholm J, Thanner J, et al. 5-year experience of highly crossed-linked polyethylene in cemented and uncemented sockets: Two randomized studies using radiostereometric analysis. Acta Orthop 2007;78(6):746-754. 

13. Leung SB, Egawa H, Stepniewski A, et al. Incidence and volume of pelvic osteolysis at early follow-up with highly crossed-linked and noncross-linked polyethylene. J Arthroplasty 2007;22(6, Suppl 2):134-139 

14. Swedish Hip Arthroplasty Register: Annual Report 2013. https://registercentrum.blob.core.windows.net/shpr/r/Annual-report-2013-HJnnK8Tie.pdf 

15. Australian Orthopaedic Association: National joint replacement registry annual report 2014. https://aoanjrr.sahmri.com/en/annual-reports-2014 Accessed on 6/25/18 

16. Campbell P, Shen FW, McKellop H: Biologic and tribologic considerations of alternative bearing surfaces. Clin Orthop Relat Res 2004;418:98-111. 

17. Macdonald N, Bankes M: Ceramic on ceramic hip prostheses: A review of past and modern materials. Arch Orthop Trauma Surg 2014;134(9):1325-1333. 

18. Di Puccio F, Mattei L: Biotribology of artificial hip joints. World J Orthop 2015;6 (1):77-94. 

19. Esposito C, Maclean F, Campbell P, et al. Periprosthetic tissues from third generation alumina-on-alumina total hip arthroplasties. J Arthroplasty 2013;28(5):860-866. 

20. So K, Goto K, Kuroda Y, et al. Minimum 10-year wear analysis of highly cross-linked polyethylene in cementless total hip arthroplasty. J Arthroplasty 2015; 30(12):2224-2226. 

21. Epinette JA, Manley MT: No differences found in bearing related hip survivorship at 10-12 years follow-up between patients with ceramic on highly cross- linked polyethylene bearings compared to patients with ceramic on ceramic bearings. J Arthroplasty 2014;29(7): 1369-1372. 

22. Kim YH, Park JW, Kulkarni SS, et al. A randomised prospective evaluation of ceramic-on-ceramic and ceramic-on-highly cross-linked polyethylene bearings in the same patients with primary cementless total hip arthroplasty. Int Orthop 2013;37(11): 2131-2137. 

23. Nakashima Y, Sato T, Yamamoto T, et al. Results at a minimum of 10 years of follow- up for AMS and PerFix HA-coated cementless total hip arthroplasty: Impact of cross-linked polyethylene on implant longevity. J Orthop Sci 2013;18(6): 962-968. 

24. Fukui K, Kaneuji A, Sugimori T, et al. Wear comparison between conventional and highly cross-linked polyethylene against a zirconia head: A concise follow-up, at an average 10 years, of a previous report. J Arthroplasty 2013; 28(9):1654-1658. 

25. Chana R, Facek M, Tilley S, et al. Ceramic-on-ceramic bearings in young patients: Outcomes and activity levels at minimum ten-year follow-up. Bone Joint J 2013;95-B(12): 1603-1609. 

26. Synder M, Drobniewski M, Sibinski M: Long-term results of cementless hip arthroplasty with ceramic-on-ceramic articulation. Int Orthop 2012;36(11): 2225-2229. 

27. Streit MR, Schröder K, Körber M, et al. High survival in young patients using a second generation uncemented total hip replacement. Int Orthop 2012;36(6): 1129-1136. 

28. Solarino G, Piazzolla A, Notarnicola A, et al.Long-term results of 32-mm alumina- on-alumina THA for avascular necrosis of the femoral head. J Orthop Traumatol 2012;13(1):21-27. 

29. Sugano N, Takao M, Sakai T, et al. Eleven- to 14-year follow-up results of cementless total hip arthroplasty using a third-generation alumina ceramic-on-ceramic bearing. J Arthroplasty 2012;27(5):736-741. 

30. Massin P, Lopes R, Masson B, et al. French Hip & Knee Society (SFHG): Does Biolox Delta ceramic reduce the rate of component fractures in total hip replacement? Orthop Traumatol Surg Res 2014;100(6 suppl):S317-S321. 

31. Own Dh, Russell NC, Smith PN, et al, An estimation of the incidence of squeaking and revision surgery for squeaking in ceramic-on-ceramic total hip replacement: A meta-analysis and report from the Australian Orthopaedic Association National Joint Registry. Bone Joint J 2014;96-B(2):181-187. 

32. Good V, Ries M, Barrack RL, et al. Reduced wear with oxidized zirconium femoral heads. J Bone Joint Surg Am 2003;85-A(suppl 4):105-110. 

33. Australian Orthopaedic Association: National joint registry annual report 2015. https://aoanjrr.sahmri.com/en/annual-reports-2015 Accessed 6/27/18 

34. Morison ZA, Patil S, Khan HA, et al. A randomized controlled trial comparing Oxinium and cobalt-chrome on standard and cross-linked polyethylene. J Arthroplasty 2014;29(9suppl):164-168. 

35. Jassim SS, Patel S, Wardle N: Five-year comparison of wear using oxidized zirconium and cobalt-chrome femoral heads in total hip arthroplasty: A multicenter randomized controlled trial. Bone Joint J 2015;97-B(7):883-889. 

36. Karidakis GK, Karachalios T: Oxidized zirconium head on crosslinked polyethylene liner in total hip arthroplasty: A 7- to 12-year in vivo comparative wear study. Clin Orthop Relat Res 2015;473(12):3836-3845. 

37. Australian Orthopaedic Association: National joint registry annual report 2010. https://aoanjrr.sahmri.com/en/annual-reports-2010 

38. National Joint Registry for England and Wales: Seventh Annual Report. 2010. http://www.njrcentre.org.uk/NjrCentre/Portals/0/NJR%207th%20Annual%20Report%202010.pdf

HEAT SAFETY

By Michael W. Gish, M.D.

Summer has just officially arrived, and with it comes the promise of hotter weather. While many enjoy the warmth of summertime, summer’s hot temperatures (and humidity) can lead to potentially dangerous health issues when training and competing.

Exertional Heat Illness is a spectrum of conditions that can run the gamut from dehydration, heat cramps, and heat exhaustion to a potentially life-threatening condition known as Exertional Heat Stroke (EHS). Prevention, as well as knowing the early warning signs of Exertional Heat Illness, is the best way to combat these conditions. Prevention involves several factors, including heat acclimatization, adequate hydration, and proper training modifications based on monitoring environmental conditions through the Wet Bulb Globe Temperature (WBGT) — a more accurate measure of potential heat stress than just temperature alone. The WBGT is a measure of the heat stress in direct sunlight, which takes into account temperature, humidity, wind speed, sun angle, and cloud cover (solar radiation). This differs from the heat index, which only takes into consideration temperature and humidity and is calculated for shady areas. There are specific WBGT monitors as well as several phone apps designed to measure the WBGT. 

ACCLIMATIZATION

Acclimatization is the body’s natural adaptation to exercising in the heat. While there are many
recommendations on how to do this, general guidelines include avoiding the hottest part of the day (11am-4pm) for training sessions, if possible, and gradually increasing the amount of time spent training in the heat over the course of a 10-14 day period of time.

HYDRATION

Adequate hydration begins before the training session or competition. Athletes should be regularly hydrating throughout the day and should also plan to drink 12-16 ounces of fluid approximately 30 minutes before getting to the field. During activity, periodic drinking should be enforced even if the athlete does not “feel” thirsty. It is recommended that every 15-20 minutes during activity, an athlete should consume 5 ounces of fluid for a player weighing 90 lbs or less and 9 ounces of fluid for a player weighting more than 90 lbs. Once the activity is over, an athlete should drink water or a sports drink every 15-20 minutes for the first hour after activity.

TRAINING

Training modifications based on the WBGT include implementing mandatory match play hydration breaks during competition, limiting intensity or duration of training, and possibly delaying training until the WBGT decreases.

WARNING SIGNS

Early warning signs of dehydration and heat illness include increased fatigue, dizziness, nausea, headache, dry lips and tongue, irritability, muscle cramping, red flushed face, and dark yellow urine. If any of these occur, an athlete should be removed from play to a cooler, shaded area, given fluids to drink (water or an electrolyte-containing sports drink), and gently cooled with ice packs or cool wet towels. If the athlete does not rapidly improve or develops an altered mental status such as confusion or extreme lethargy, heat stroke (which is a medical emergency) should be assumed and EMS (911) should be called.

With proper awareness and prevention techniques, most heat-related illness can be avoided or minimized, and athletes can focus on enjoying training and competition during the heat of summer.

For more detailed information, refer to the following resources from which much of the material for this article was obtained:

• US Soccer Federation 2006 Youth Soccer Heat and Hydration Guidelines
• US Soccer Heat Guidelines