Hypophosphatemic vitamin D refractory osteomalacia with bilateral femoral pseudofractures.

The case of a young adult female who developed multiple orthopedic problems associated with genetic osteomalacia is presented. Pathologically in the subcapital regions of both proximal femurs severe osteomalacic callus through stress fractures was demonstrated.

Osseous manifestations of elbow stress associated with sports activities.

The radiographic manifestations of musculoskeletal stress at the elbow associated with racket and throwing sports are reported in 29 symptomatic amateur, juvenile, and professional athletes. Five major categories of stress are identified: diffuse, humeral shaft, medial tension, lateral compression, and extension stress. The osseous changes produced by these stresses include bony hypertrophy, loose bodies, traction spur formation, osteochondral and humeral shaft fractures in the adult, and epiphyseal and apophyseal hypermaturity or avulsion in the youngster.

A new method of patellectomy for patellofemoral arthritis.

Total patellectomy, although it has a biomechanical disadvantage in that it may lead to a degree of quadriceps weakness, is frequently indicated in selected patients. Numerous different techniques of performing patellectomy have been described. In this paper, we present a technique of performing a patellectomy in which the continuity of the quadriceps mechanism is not disrupted and the vastuc medialis is advanced. Twenty-six patients (twenty-nine knees) in whom the procedure was performed were studied retrospectively. The findings in this series showed 90 per cent good or excellent results, two cases of extensor lag, an average of 118 degrees of knee flexion, minimum quadriceps atrophy with good strength, and minimum postoperative immobilization. The method presented has the important advantage of an easier, smoother postoperative knee-rehabilitation period, which is extremely advantageous in elderly patients.

The number of total joint replacements in the United States.

By comparing estimates from several sources an assessment can be made of the number of total joint replacement procedures performed annually in the United States. Approximately 80,000 hips and 40,000 knee joints were replaced in the U.S. during 1976. Total hip replacement has been accepted by the orthopedic community as an efficacious mode of treatment of the many painful and disabling forms of arthritis. A substantial patient population could benefit from perfection of designs for treating joints other than the hip.

Dislocations after total hip-replacement arthroplasties.

In a series of 300 total hip replacements, nine (3 per cent) dislocated. Precise measurements of the orientation of the acetabular cup were made and it was found that anterior dislocations were associated with increased acetabular-component anteversion. There was no significant correlation between cup-orientation angle and posterior dislocation. The dislocation rate for cup orientation with anteversion of 15 +/- 10 degrees and lateral opening of 40 +/- 10 degrees was 1.5 per cent, while outside this "safe" range the dislocation rate was 6.1 per cent. Other factors that were documented include time after surgery (with the greatest risk in the first thirty days) and surgical history (with a greater risk in hips that have had prior surgery).

Degree of polymerization of acrylic bone cement.

Self-curing powder-liquid admixed acrylic systems are used for internal fixation fo total hip and total knee prostheses. Gel permeation chromatography revealed that the polymer chain length distributions of set cements were basically unaffected by their curing pressures. However, a decrease of approximately 11% in porosity coupled with a measured increase in mechanical strengths could be induced through the use of high curing pressures well beyond those attainable by the surgeon in the current arthroplasties. The conclusion of the investigation was that, to improve such cements, attention should be focused on elimination of porosity rather than attempting to produce higher degree of polymerization.