Range of motion in total knee replacement.

This is a multicenter prospective clinical study using a modified Knee Society scoring system which evaluated the effect of age, gender, weight, preoperative range of motion and knee score, previous surgery, and modification of the posterior femoral condyle geometry on postoperative range of motion. The primary outcome variable was change in flexion. The data were collected from 5 surgeons using a single total knee system. The current study has 621 patients enrolled, of which 282 total knee replacements have followup of 12 months and 86 have followup of 24 months. Multivariate analysis was used to evaluate the data. The variables listed were examined as to their relationship to changes in flexion. Patients were divided into 3 groups: preoperative flexion less than 90 degrees, 91 degrees to 105 degrees, and greater than 105 degrees. When comparing the patients with preoperative motion less than 90 degrees to those with motion greater than 105 degrees, the first group improved 26 degrees more than the latter. They also improved 12 degrees more than the midrange group. The midrange group improved 14 degrees more than the upper range group. These values are all adjusted to eliminate differences due to the other variables. None of the other variables showed a significant correlation with the flexion outcome. To analyze the knee score, the group was also divided into 3 groups: preoperative score less than 27, 28 to 40, and greater than 40. The preoperative knee score was the best predictor of the postoperative knee score. The patients with preoperative knee scores below 27 improved 16 points more than those in the 27 to 40 range and 33 points greater than the greater than 40 group. To analyze functional evaluation, the patients were divided into 3 groups based on preoperative score: less than 40, 41 to 50, and greater than 50. Those in the less than 40 group improved 14 points more than the midrange group and 35 points more than the greater than 50 group. Analysis of delta range of motion and delta pain showed similar results. Age, weight, previous open surgical procedure, and altered femoral component contour, did not seem significantly correlated with changes in postoperative flexion. The best predictors of postoperative clinical results are the preoperative scores.

The effects of axial rotational alignment of the femoral component on knee stability and patellar tracking in total knee arthroplasty demonstrated on autopsy specimens.

Four fresh-frozen anatomic knee specimens were tested for knee stability, patellar tracking, and patellofemoral contact points with the femoral component positioned in 5 degrees internal, 5 degrees external, or neutral axial rotational alignment of the femoral component referenced on the posterior femoral condyles. The externally rotated specimens had varus-valgus stability of the knee that was closest to the normal control. The internally rotated specimens shifted into valgus alignment with flexion. Patellar tracking also was closest to normal in the externally rotated specimens. Patellofemoral contact was more evenly distributed between the medial and lateral contact areas in the externally rotated specimens than in the internally rotated or in the neutral specimens. Internal rotation of the femoral component in the knee with perpendicular resection of the tibia causes undesirable changes in knee stability, patellar tracking, and patellofemoral contact points. Neutral positioning produces similar but less negative effects on knee stability and patellar kinematics. External rotation improves both patellar tracking and knee stability characteristics.

The effect of patellar button placement and femoral component design on patellar tracking in total knee arthroplasty.

The effects of patellar button position and femoral component design on patellar tracking were investigated roentgenographically and arthroscopically using fresh-frozen adult anatomic specimen knees. Patellar tracking was evaluated for medial/lateral position and tilting angle deviation by comparing preoperative normal values to total knee replacement performance with the following variables: (1) femoral component design; symmetrical total condylar type with a 3-mm central patellar groove and a component with a 3-mm raised lateral patellar flange and 1-mm deepened patellar groove; and (2) patellar button placement; central insertion; and 10-mm medialized insertion. In the roentgenographic study, medialized position of the patellar button allowed the bony portion of the patella to assume its normal lateral position and tilt throughout the knee range of motion. A combination of medialized position of the patellar button and deepening of the patellar groove provided the most anatomically correct position and the most normal tilting of the bony structure of the patella. In the arthroscopic study, the centralized patellar position caused significant lateral tracking and subluxation relative to the femoral component, whereas the medialized position eliminated this tracking disorder. Deepening the patellar groove minimized the intraarticular tracking abnormality and constrained the patellar button in the patellar groove. These results show that the position of the patellar button and femoral component design exert a major influence on patellar tracking.

Ulnar nerve decompression with medial epicondylectomy for neuropathy at the elbow.

Ulnar nerve decompression with medial epicondylectomy was performed in 66 elbows between 1966 and 1986 for compressive ulnar neuropathy at the elbow. This study is an updated review that adds 36 cases to a previously published report on 30 cases. These elbows were graded preoperatively and postoperatively using McGowan's grading system. Eighty-three percent improved one or two grades, and 11% improved subjectively although they showed no objective improvement, 3% noted no change, and 3% were subjectively worse. One early case sustained damage to the ulnar collateral ligament with resultant instability. No other complications occurred. The best results were seen in the Grade I and II lesions, whereas those with Grade III lesions were the least predictable. The procedure is technically uncomplicated with minimal morbidity and reliable results.

Hand infections with Mycobacterium chelonei: a case report and review of the literature.

A case is reported of soft-tissue infection in the hand due to Mycobacterium chelonei, presenting as a chronic painful swelling of a finger.

Posterior compartment syndrome of the calf resulting from misdiagnosis of a rupture of the medial head of the gastrocnemius.

Rupture of the medial head of the gastrocnemius muscle has frequently been confused with thrombophlebitis. The distinction between these two entities is important and may be difficult to ascertain. Misdiagnosis may result in unnecessary complications. An illustrative case, in which venography, MRI, and compartment pressure measurements were diagnostic, is presented.