2010 AAOS Annual Meeting Hot Topics

Short, abstract highlights coming out of the AAOS 2010 Annual Meeting in New Orleans

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NEW ORLEANS, March 12 /PRNewswire-USNewswire/ -- The following is being issued the by American Academy of Orthopaedic Surgeons:

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Hormonal Influence on Joints in Female Athletes

• The presence of shoulder laxity was correlated with generalized laxity in female swimmers.

Generalized laxity, or looseness in the joints, is thought to occur more commonly in women than in men. A pilot study found that mean hormone levels in female swimmers demonstrated a greater trend for those with generalized laxity than for those with no generalized laxity. The use of oral contraceptives affected laxity scores, a measure of joint looseness and total testosterone levels.

Achilles Tendon Rupture

• Surgery may not be necessary for Achilles tendon ruptures (ATR).  Early rehabilitation appears to provide the same outcome for patients treated with or without surgery for ATR.

Patients with acute Achilles tendon rupture (ATR) who underwent mobility and rehabilitation protocols soon after injury appear to experience the same outcome one year later, regardless of whether they were treated with surgery.  There is currently no consensus on the optimal treatment for ATR. Researchers concluded that early mobilization treatment should be used with all ATR patients, regardless of whether surgery was used to treat the rupture.

Risk Factors for Low Back Pain in the Military

• Being married, having a low rank and being female appear to be risk factors for diagnosis of low back pain in active duty military personnel.

Low back pain is one of the most common musculoskeletal conditions in the world. In the largest study of its kind, data from more than 550,000 active duty military over the last decade were reviewed to determine what the most significant risk factors are for the development of low back pain within this group.  Four significant risk factors in the military population for low back pain are: being female, being older than 35 years of age, being married and having a junior enlisted rank. Army and Air Force patients are diagnosed with more low back pain than those in the Marines.

Non-battle Injuries and Disease Represent the Majority of Iraq War Soldier Casualties

• Musculoskeletal injuries accounted for 50 percent of disease and non-battle injuries and 38 percent of all casualties in one U.S. Brigade Combat Team

While injuries sustained during battle were expected during the Iraq War, disease and non-battle injuries have now accounted for 75 percent more casualties than war injuries. When measuring casualties for one U.S. Brigade Combat Team, musculoskeletal injuries comprised 50 percent of the disease and non-battle injuries sustained by the group and represented 38 percent of the casualties. The top five locations for soldiers' musculoskeletal injuries were the hand, lumbar spine, knee, ankle and shoulder. The incidences of ACL rupture and first-time shoulder dislocation for combat soldiers were five times greater than what is found in the general population.

Postoperative Exercise after Total Knee Arthroplasty

• Snow skiing on moderate downhill slopes creates the same force on the knees as jogging.

After total knee arthroplasty, patients are frequently directed not to return to full athletic activity in order to prevent long-term wear and damage. To measure this, the in vivo forces generated during recreational snow skiing were measured. Skiing on gentle slopes and/or "snowplowing" appear to generate lower forces than level walking or stationary biking. Stopping and/or "skating" on skis created forces similar to climbing stairs, and skiing on moderate slopes – those rated as "blue" – generated the same high forces seen in jogging.  

Nurse Staffing Affects Mortality Rates among Hip-fracture Patients

• The risk of death for elderly patients in the hospital with hip fractures increases 22 percent when staffing is reduced by one full-time nurse each day.

The number of full-time nurses on staff appears to influence the mortality rates for elderly patients admitted to the hospital with hip fractures. Low nurse staffing levels are associated with increased mortality in other inpatient scenarios, but until now had not yet been reviewed in orthopaedic surgery. When nurse staffing levels are reduced by one full-time nurse per patient-day, there is a 16 percent increase in the risk of death for hip fracture patients. For patients with hip fractures, the odds of mortality decreased for every additional full-time registered nurse on the staff per day.

Ultrasound Screening for Hip Dysplasia in Breech Infants

• Breech infants can develop dysplasia up to six months after birth.

When ultrasound exams were performed on breech infants to look for developmental dysplasia of the hip at six weeks of age, 24 percent of these infants were shown to have dysplasia. When breech infants with normal ultrasounds at six weeks were again examined at six months, an additional 12 percent were diagnosed with dysplasia.  Due to this finding, it is recommended that all breech infants have additional follow-up X-rays four to six months after birth.

Distinguishing Lyme Arthritis in Children

• 45 percent of children with fluid in the knee in the northeastern U.S. are likely to have Lyme arthritis.

In the northeastern United States where Lyme disease is more prevalent, 31 percent of the children with fluid in their joints (joint effusion), were found to have Lyme arthritis, not septic arthritis. When joint effusion was found in the knee, rather than another joint, the rate for Lyme arthritis jumped to 45 percent. A child with Lyme arthritis and not septic arthritis tends to have a lower white blood cell count, no fever and may be able to bear weight on the affected limb.

Affect of Sleep Apnea on Surgical Patients

• Patients with sleep apnea are more likely to experience complications after surgery.

Patients with obstructive sleep apnea (OSA) are at a higher risk for developing serious complications after surgery, some of which can be life threatening. These patients have higher rates of acute renal failure, as well as low oxygen blood levels and longer hospitalization after surgery.  It is recommended that strict protocols be used to monitor OSA patients during recovery after surgery.

Longevity of Cemented vs. Cementless Total Hip Replacements

• Cementless stems and cups are recommended for younger patients with total hip replacements because they are more resistant to aseptic loosening.

Implants used in total hip replacements are currently available with cemented or cementless stems and cups. Cementless stems and cups appear to be more resistant to aseptic loosening than their cemented counterparts. Normal wear and tear can cause aseptic loosening where the replacement joint loses its binding to the patient's skeleton. After 15 years, 89 percent of cementless stems were still in place compared to only 72 percent of cemented stems. During this same time period, 80 percent of cementless cups had survived compared to only 71 percent of cemented cups.  These results indicate that younger patients should consider cementless total hip replacements due to their longer longevity.

Outcomes of Resurfacing Hip Replacement

• Eight years after surgery, the risk of replacement of implants after resurfacing procedures is much higher for most patient groups than total hip replacement.

The outcomes of resurfacing hip replacement depend heavily on the patient and the prosthesis selected for that patient. The best results eight years after surgery are in men younger than age 55 who have osteoarthritis, who have the same rate of revision (replacement of the implant) as patients who had total hip replacement. In all other groups of patients, there was an increased risk of revision. Women of all ages and patients with a diagnosis other than osteoarthritis have a significantly increased risk of implant replacement. As for the type of prosthesis used, the ASR and Durom prostheses appear to have a higher risk of requiring replacement than the BHR prosthesis.

Ankle Sprain Injuries

• The risk for ankle sprain is highest between the ages of 10 and 20, often while playing basketball.

Almost half of all ankle sprain injuries happen during athletic activity, and 41 percent of those occur while playing basketball. Sprains appear to be most common during the second decade of life. For men, these injuries occur most frequently between the ages of 15 and 19. For woman, they are most frequent between 10 and 14 years of age. Men have more ankle sprains than women between the ages of 15 and 24, and women have higher rates of ankle sprains than men do over the age of 30.

Night Time Arrival at the Hospital Associated with Mortality Rates

• Arriving at the hospital between midnight and 6 a.m. is linked to higher mortality rates than arriving at other times of the day.

Mortality rates for patients arriving at the hospital after midnight were substantially higher than those for patients arriving in the morning or afternoon. The level of the trauma center receiving a patient also affects the mortality rate. Level III and IV trauma centers have the highest mortality rate and Level I trauma centers have the lowest.

Insurance Status Often Determines Treatment for Fractures Requiring Surgery

• Patients with operative fractures who do not present directly to a trauma center for care are more likely to be under- or uninsured.

Non-medical reasons seem to be a factor when and if an ambulatory patient receives care for operative fractures. Patients who have been treated at a Level I trauma center and are later discharged after their initial care must find a surgeon for later, definitive care. Patients who are underinsured or uninsured were 2.6 times more likely to have had their operative treatment at a Level I trauma center after having initial treatment performed some place else.

Patient Satisfaction after Total Knee Replacement

• More than 95 percent of patients are satisfied with the outcome of their total knee replacement (TKR) one year after surgery.

Some experts say TKR is the best elective surgical procedure in medicine today.  In addition, the four percent of patients who were not satisfied with the results of their knee replacement tended to be younger, female patients, and those with posttraumatic arthritis.  The study involved data from 6,364 patients with total knee replacements between 2000 and 2005.  It represents national data from 224 hospitals in 32 states across the country.

Narcotic Use and Satisfaction after Knee Replacement

• Few patients need narcotic pain killers after undergoing total knee replacement (TKR).

TKR is an effective procedure to relieve pain from advanced osteoarthritis of the knee, with more than 95 percent of patients reporting satisfaction with the outcome. Eighteen percent of patients took at least one form of narcotic pain medication before surgery. Of those people, only 15 percent reported taking pain medication 12 months after surgery. However, researchers also found that compared to patients who did not take narcotics pre-operatively, patients who took narcotics pre-operatively reported more pain and were less satisfied with the outcome.

Pediatric Injuries and Orthopaedic Care

• Children who sustain high-energy injuries need thorough orthopaedic care; as fractures may be missed.

If a child or teen suffers a high-energy injury, such as jumping or falling from heights; a motor vehicle collision; or a motorcycle or bicycle accident, they should be further evaluated for a possible tibial spine fracture.  Typically, the instinct is to check for anterior cruciate ligament (ACL) injuries, but this study aims to increase awareness that a tibial spine fracture may also be present.  

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SOURCE American Academy of Orthopaedic Surgeons