This study revealed that the knee arthroscopy rate in the United States was more than twofold higher than in England or Ontario, Canada, in 2006. Our study found that nearly half of the knee arthroscopic procedures were performed for meniscal tears. Meniscal damage, detected by magnetic resonance imaging, is commonly assumed to be the source of pain and symptoms. Further study is imperative to better define the symptoms, physical findings, and radiographic findings that are predictive of successful arthroscopic treatment.

Eighty consecutive patients with chronic laxity due to a torn ACL underwent arthroscopically assisted reconstruction with either autogenous patellar tendon or doubled semitendinosus and gracilis tendons. Reconstructions were performed on a one-to-one alternating basis. Preoperatively, no significant differences between the two groups were noted with respect to age, sex, level of activity, and degree of laxity (chi square analysis). A standard rehabilitation regimen was used for all patients after surgery including immediate passive knee extension, early stationary cycling, protected weightbearing for 6 weeks, avoidance of resisted terminal knee extension until 6 months, and return to activity at 10 to 12 months postoperatively. Seventy-two patients were evaluated at a minimum of 24 months postoperatively (range, 24 to 40 months). No significant differences were noted between groups with respect to subjective complaints, functional level, or objective laxity evaluation, including KT-1000 measurements. Seventeen of 72 patients (24%) experienced anterior knee pain after ACL reconstruction. Overall, 46 of 72 patients (64%) returned to their preinjury level of activity. Mean KT-1000 scores were 1.6 +/- 1.4 mm for the patellar tendon group and 1.9 +/- 1.3 mm for the semitendinosus and gracilis tendons group. This study did find a statistically significant weakness in peak hamstrings torque at 60 deg/sec when reconstruction was performed with double-looped semitendinosus and gracilis tendons.

Objective. To evaluate the occurrence of emergency department (ED) visits due to humerus fractures in the US. Methods. We analyzed the 2008 Nationwide Emergency Department Sample, which contained approximately 28 million ED records. We identified the cases of interest using diagnostic codes for proximal, shaft, and distal humerus fractures. Results. In 2008, approximately 370,000 ED visits in the US resulted from humerus fractures. Proximal humerus fractures were the most common, accounting for 50% of humerus fractures. The incidence rate of proximal humerus fractures followed the shape of an exponential function in the age groups 40 -84 years for women (R 2 ‫؍‬ 97.9%) and 60 -89 years for men (R 2 ‫؍‬ 98.2%). After the exponential increase in these age intervals, the growth rate of proximal humerus fracture slowed and eventually decreased. The peak occurrence of distal humerus fractures was in children ages 5-9 years; however, elderly women had an increased risk. As the baby boomer generation ages, unless fracture prevention programs improve, more than 490,000 ED visits due to humerus fractures are expected in 2030 when the youngest of the baby boomers turn age 65 years. Conclusion. Compared to epidemiologic studies in Japan and European countries, the incidence rates of humerus fractures are substantially higher in the US. The high incidence rate of humerus fractures in the expanding elderly population may contribute to the recent trend of rapid increase in shoulder arthroplasty in the US. Rigorous safety measures to reduce falls and improved preventive treatments of osteoporosis are needed.

We measured strain in the lateral ligaments of 10 human cadaver ankles while moving the ankle joint and applying stress in a variety of ways. We studied the anterior talofibular, calcaneofibular, posterior talofibular, anterior tibiofibular, and posterior tibiofibular ligaments. Strain measurements in the ligaments were recorded continuously while the ankle was moved from dorsiflexion into plantar flexion. We then repeated measurements while applying inversion, eversion, internal rotation, and external rotation forces. Strain in the anterior talofibular ligament increased when the ankle was moved into greater degrees of plantar flexion, internal rotation, and inversion. Strain in the calcaneofibular ligament increased as the talus was dorsiflexed and inverted. These findings support the concept that the anterior talofibular and calcaneofibular ligaments function together at all positions of ankle flexion to provide lateral ankle stability. We measured maximum strain in the posterior talofibular ligament when the ankle was dorsiflexed and externally rotated. The strain in the anterior and posterior tibiofibular ligaments increased when the ankle was dorsiflexed. External rotation increased strain in the anterior tibiofibular ligament and decreased strain in the posterior tibiofibular ligament. Based upon strain measurements in the lateral ankle ligaments in various ankle joint positions, we believe the anterior talofibular ligament is most likely to tear if the ankle is inverted in plantar flexion and internally rotated. Theoretically, the calcaneofibular ligament tears primarily in inversion if the ankle is dorsiflexed; the anterior tibiofibular ligament tears in dorsiflexion, especially if combined with external rotation; and the posterior tibiofibular ligament tears with extreme dorsiflexion.

To determine the influence of rotator cuff muscle activity on humeral head migration relative to the glenoid during active arm elevation we studied five fresh cadaveric shoulders. The shoulder girdles were mounted in an apparatus that simulated contraction of the deltoid and rotator cuff muscles while maintaining the normal scapulothoracic relationship. The arms were abducted using four different configurations of simulated muscle activity: deltoid alone; deltoid and supraspinatus; deltoid, infraspinatus, teres minor, and subscapularis; and deltoid, supraspinatus, infraspinatus, teres minor, and subscapularis. For each simulated muscle configuration the vertical position of the humeral head in relation to the glenoid was determined at 30 degrees, 60 degrees, 90 degrees, and 120 degrees of abduction using digitized anteroposterior radiographs. Both muscle activity and abduction angle significantly influenced the glenohumeral relationship. With simulated activity of the entire rotator cuff, the geometric center of the humeral head was centered in the glenoid at 30 degrees but had moved 1.5 mm superiorly by 120 degrees. Abduction without the subscapularis, infraspinatus, and teres minor muscles caused significant superiorly directed shifts in humeral head position as did abduction using only the deltoid muscle. These results support the possible use of selective strengthening exercises for the infraspinatus, teres minor, and subscapularis muscles in treatment of the impingement syndrome.