Primary total hip arthroplasty with a porous-coated acetabular component. Seven-to-ten-year results

One hundred and eighty-four patients who had been managed, between 1984 and 1985, with a total of 204 consecutive primary total hip arthroplasties with insertion of a Harris-Galante type-I acetabular component without cement were prospectively studied. There were eighty-two men (45 per cent) and 102 women (55 per cent). The mean age at the time of the operation was fifty-two years (range, twenty to eighty-four years). One hundred and fifty-seven patients (173 hips) were available for clinical review at a mean of 104 months (range, seventy-eight to 126 months). At this time, the mean preoperative Harris hip score of 52 points (range, 12 to 79 points) had improved to a mean of 90 points (range, 44 to 100 points). Two patients (two hips) had an exchange of an excessively worn polyethylene liner. One patient (one hip) had debridement and grafting of an area of massive retroacetabular osteolysis. Two stable acetabular components (1 per cent) had been revised at the time of femoral revision. None of the cups had been revised because of aseptic loosening. Radiographic examination of 150 patients (165 hips) at a mean of 104 months (range, seventy-eight to 126 months) revealed that 156 cups (95 per cent) were stable. Eight cups (5 per cent) were considered to be possibly unstable, with a radiolucent line between the prosthesis and the bone that was one millimeter wide or less in at least four of five zones; two of the eight had a complete radiolucent line in all zones. One component, which had been implanted with a bulk allograft from a femoral head, migrated more than two millimeters in the first two years and then stabilized without complication. Osteolysis was seen in seven acetabula (4 per cent) and was limited to the periphery of the cup in six. Survivorship analysis at ten years revealed that the acetabular component had a 99 per cent chance of survival (95 per cent confidence interval, 0.98 to 1.0) with revision or aseptic loosening as the end point and a 97 per cent chance of survival (95 per cent confidence interval, 0.95 to 1.0) with revision, aseptic loosening, or reoperation because of a problem related to the acetabular component as the end point.

Altered load history affects periprosthetic bone loss following cementless total hip arthroplasty

Dual energy x-ray absorptiometry was used to measure periprosthetic, distal femoral, and proximal tibial bone mass in the affected and contralateral limbs of eight patients 10 years after unilateral total hip arthroplasty with a cementless, porous-coated titanium alloy femoral stem. Gait analyses to assess the presence of asymmetries in loading of the lower extremities were also performed 10 years postoperatively. The patients had excellent clinical results and no other significant lower extremity pathology. On the basis of comparison of the affected and unaffected proximal femora, bone loss adjacent to the proximal medial aspect of the femoral stem was determined to be 34% (p < 0.001). However, the patients also had 16% less bone in the ipsilateral proximal tibia (p = 0.003) and 15% less bone in the ipsilateral femur 3 cm distal to the prosthesis (p = 0.007) compared with the contralateral limb. When normalized to the asymmetry in tibial bone mineral content, the estimated proximal medial periprosthetic bone loss was still statistically significant, but the magnitude was reduced from 34 to 17% (p = 0.009). The gait analyses indicated that several measures that influence the loads at the hip and knee joints were reduced in the involved limb compared with the contralateral limb. Furthermore, the bilateral difference in the vertical component of the external force acting on the proximal tibia was correlated with the bilateral difference in tibial bone mineral content (r = 0.80, p = 0.02). These data suggest that two mechanical factors, the local stress-shielding effect of the prosthesis and the global effect of decreased loading of the limb, can both make significant contributions to periprosthetic bone loss. It is apparent that the magnitude of the periprosthetic bone loss related to stress-shielding has been overestimated by as much as 50% in retrospective studies.

Myositis ossificans after tetanus: treatment aided by quantitative technetium Tc 99m pyrophosphate radionuclide imaging

Functionally disabling myositis ossificans of the posterior aspect of the elbow occurred in a 66-year-old man as a sequela of tetanus. Serial quantitative bone scans were done to determine the optimal time for excision, which produced an excellent functional result without recurrence at 4 years.

A prospective study of a titanium femoral component for cemented total hip arthroplasty

The authors studied the clinical and radiographic results of a modern titanium-alloy femoral stem with a cobalt-chrome-alloy head for use in cemented total hip arthroplasty. One hundred sixteen hips (102 patients) were operated on using modern cement techniques and prospectively followed using the Hospital for Special Surgery hip rating system and standard radiographic criteria. At a mean follow-up period of 4.8 years (range, 2-8 years), 69 hips were rated excellent, 38 good, 4 fair, and 5 poor. A total of 13 femoral components (11%) were radiographically loose according to the criteria of Harris. In 11 of these loose femoral components, debonding or separation at the cement-prosthesis interface, was the initial cause of failure, with bone-cement interface erosions occurring later in five hips. Revision of a loose femoral component has been performed in three hips and is pending in two other hips (4.3%). Significant calcar resorption was seen in only 17 hips (14.6%), and serial measurements of distal femoral cortical widths showed no distal cortical hypertrophy except in one femur. The incidence of loosening with this cemented titanium-alloy femoral component (with a cobalt-chrome-alloy head) is much higher than published reports of similar cobalt-chrome-alloy stems. The authors have abandoned the use of titanium-alloy femoral components for cemented total hip arthroplasty.

Bilateral simultaneous fractures of the femoral neck: case report

A case of bilateral fractures of the femoral neck resulting from high-voltage electric injury is reported. Surgeons caring for patients with electrical injuries must be aware of the possibility of this injury as well as other skeletal injuries which may result from muscle contraction or falls related to electric shock. Without vigilance for these injuries, diagnosis may be delayed.

Inhibition of pepsin activity by unconjugated bile acids. Inverse relation to number of hydroxyl groups

The unconjugated bile acids cholic, deoxycholic, chenodeoxycholic, and lithocholic acid were each found to inhibit pepsin activity in vitro against the refined substrate n-adenosyl-L-phenylalanyl-L-3,5-diiodotyrosine (n-APDT). The degree of inhibition was inversely proportional to the number of hydroxyl substituents on the bile acid molecule. The implications of these findings in relation to the occurrence of peptic ulceration in patients undergoing Roux-Y biliary diversion is discussed.