Magnetic resonance imaging as a tool to predict meniscal reparability.

One hundred six patients who underwent high field strength magnetic resonance imaging and subsequent arthroscopy of the knee were evaluated to determine the accuracy of magnetic resonance imaging in predicting meniscal tear reparability. Each scan was independently read by three examiners with varying degrees of expertise: a musculoskeletal radiologist, a senior orthopaedic surgeon, and a general radiologist. Each suspected tear was characterized by its morphologic type, maximum length, and minimum distance from the meniscosynovial junction. A prediction was then made of whether the tear was reparable. There were 115 meniscal tears noted in the 106 patients studied. The examiners' ability to correctly estimate tear type was only fair, with correct estimates made only 14% to 67% of the time. The overall correlation of the three examiners to correctly predict the method of treatment was fair. The average accuracy, sensitivity, specificity, positive predictive value, and negative predictive value of magnetic resonance imaging in predicting meniscal reparability were 74%, 29%, 89%, 50%, and 80%, respectively; for predicting meniscectomy, these values were 69%, 68%, 75%, 90%, and 43%, respectively. There were no significant differences between the three examiners in the accuracy of their treatment predictions. The results of this study suggest that magnetic resonance imaging is only moderately reliable for the prediction of meniscus reparability. In addition, the training of the reader does not appear to significantly influence the results.     

Ankle syndesmosis sprains in national hockey league players

BACKGROUND: Although syndesmosis sprains are less common in sports than lateral ankle sprains, they represent a significant source of morbidity. Several studies have described the increased recovery time for these injuries in a variety of sports. No previous study has described this injury in hockey players. HYPOTHESIS: Syndesmosis ankle sprains require a longer recovery time and are less common than lateral ankle sprains in elite hockey players. STUDY DESIGN: Uncontrolled retrospective review. METHODS: The medical records of the St Louis Blues (1994-2001) and Dallas Stars (1991-2001) National Hockey League teams were reviewed by the head athletic trainers. Ankle sprains were identified and divided into 2 groups: syndesmosis and lateral sprains. Player demographics, treatment, and time lost to play were recorded for each injury. RESULTS: Fourteen players were diagnosed with syndesmosis sprains, and 5 players sustained lateral sprains during this time period. Mean time to return to play in games was 45 days (range, 6-137 days) for syndesmosis sprains versus 1.4 days (range, 0-6 days) for lateral sprains. CONCLUSIONS: Syndesmosis sprains represent a significant injury in hockey players with an extended time lost and, unlike in other sports, are a more common injury than lateral ankle sprains.     

Gender differences in surface rolling and gliding kinematics of the knee

The purpose of the current study was to determine whether knee surface rolling and gliding kinematics differed between genders during open and closed kinetic chain movement conditions. Eleven unimpaired adults (six men and five women) participated in this study. Sagittal plane path of instant center of rotation measurements were obtained with videographic motion analysis and applied to a mathematical knee model from which joint surface rolling and gliding kinematics were obtained. In addition, normalized electromyographic data were collected from subjects' quadriceps and hamstring muscles. During closed kinetic chain knee extension, as the knee approached terminal extension, female participants showed significantly greater relative joint surface gliding than male participants. Female participants also extended the knee in the closed kinetic chain with less relative hamstring activity than males. The relationship between joint surface gliding and relative hamstring activity in females during closed kinetic chain knee extension may explain, in part, the greater incidence of noncontact anterior cruciate ligament injury that occurs in females.     

A biomechanical comparison between the central one-third patellar tendon and the residual tendon.

The purpose of this study was to compare the tensile strength of the central one third patellar tendon--as used for reconstruction of the anterior cruciate ligament--to that of the residual patellar tendon. Ten matched pairs of human cadaveric knees were used for this study, each specimen consisting of an intact patella-patellar tendon-proximal tibial unit. One knee from each pair was randomly selected for removal of both the medial and lateral one third of the patellar tendon, leaving the central one third intact. The contralateral knee of each pair underwent removal of the central one third of the patellar tendon, leaving the residual two thirds intact. Each specimen was then mounted in a materials testing machine and tensile tested to failure at a strain rate of 100%.s-1. The most important result to emerge from these experiments was that there was no significant difference in maximum force to failure for the residual patellar tendon compared to the central one third. Thus any thought that removal of the central one third as a graft still leaves a tendon twice as wide and therefore twice as strong as a graft is dispelled by these experiments.     

Surgical options for meniscal replacement

As a result of biologic issues and technical limitations, repair of the meniscus is indicated for unstable, peripheral vertical tears; most other types of meniscal tears that are degenerative, significantly traumatized, and/or located in an avascular area of the meniscus are managed with partial meniscectomy. Options to restore the meniscus range from allograft transplantation to the use of synthetic technologies. Recent studies demonstrate good long-term outcomes from meniscal allograft transplantation, although the indications and techniques continue to evolve and the long-term chondroprotective potential has yet to be determined. Several synthetic implants, none of which has US Food and Drug Administration approval, have shown some promise for replacing part or all of the meniscus, including the collagen meniscal implant, hydrogels, and polymer scaffolds.