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Excessive polyethylene debris generated from a total hip arthroplasty can lead to osteolysis and premature revision. Most of this polyethylene debris comes from the concave articulation. However, abrasive wear on the convex side of a modular polyethylene component also may play a role in this problem. Motion of a modular polyethylene liner with respect to its shell can lead to such abrasive wear. Six samples of modular acetabular components from eight manufacturers were tested for motion between the shell and the liner. Motion at the shell liner interface was detected by five fiberoptic sensors in the x, y, and z planes. Micromotion occurred at the shell liner interface in all designs tested. The magnitude of motion varied between manufacturers, ranging from 5 to 311 microns. Design features that limit motion may be advantageous in limiting the amount of polyethylene debris.

Twenty-five patients with documented infection of the hip were reviewed. All patients underwent reconstruction in a 2-stage fashion with cementless implants. The average follow-up in this group was 41 months. The average time to reimplantation was 4.8 months. Of the 25 living patients, 22 retained their implants. There were 2 recurrences of infection, for an infection recurrence rate of 8% (2 of 25). The average postoperative Harris Hip Score was 81. Bone ingrowth was confirmed radiographically via the Engh fixation score in all but 1 of the surviving implants. Cementless fixation in 2-stage reimplantation can result in acceptable eradication rates, while supplying predictable fixation, provided that appropriate cementless revision implants are used.

Between 1986 and 1996, 268 revision total knee replacements were performed. Revisions for aseptic loosening were reviewed prospectively. Sixty-three patients had implants revised for aseptic loosening. Thirty-six of the patients had revisions of cemented constructs, whereas 27 of the patients had revisions of cementless constructs. The average time before revision for the cemented group was 86 months. The average time to revision for the cementless group was only 43 months. Fifty-two percent of the patients in the cementless group had revision of their implants within 2 years of their index arthroplasty. The average pain free interval for the cementless group was only 11 months with 63% of the patients having no pain relief after their index arthroplasty. The average postoperative score for the cementless group was 88, whereas the average postoperative score for the cemented group was 82. Revision of failed cementless total knee implants with cement is a reliable procedure. Results are similar to those of cemented knees revised with cement.

Twenty-five knees in 24 patients with infected total knee replacements were treated with debridement, component removal, and insertion of an antibiotic impregnated cement spacer block. Intravenous antibiotics were administered for 6 weeks during which time the patients' knees were kept in a knee immobilizer nonweightbearing. These cases were reviewed retrospectively to determine radiographically the amount of bone loss that occurred during the period before reimplantation. Tibial and femoral bone loss occurred frequently from invagination of the cement spacer block into the femoral and tibial cancellous bone. Tibial bone loss was present in 10 (40%) cases and averaged 6.2 mm. Femoral bone loss was present in 11 (44%) cases and averaged 12.8 mm. Bone loss was more common when spacer blocks were undersized. None of the 15 spacer blocks that were made with a small intramedullary stem displaced. Three of the remaining 10 spacer blocks made without an intramedullary stem did displace with associated bone loss. Antibiotic spacer blocks used in the two-stage treatment of infected total knee replacements can be associated with subsequent tibial and femoral bone loss.

Four hundred and fifteen patients with cementless acetabular components of either a smooth threaded (130) or porous surfaced (285) variety were compared for clinical symptoms and radiographic signs of component loosening. At a mean 4.8 year follow-up none of the patients with porous acetabular components had signs of component instability. At a mean 3.9 year follow-up 27 (21%) of the patients with a smooth threaded acetabular component showed radiographic signs of instability and 33 (25%) had clinical symptoms. The disappointing short-term results with these threaded cups in our hands have prompted us to abandon their use in favour of the porous surfaced hemispherical cups.

A case of symptomatic ossification of the pterygomandibular raphe, believed to be the first reported case of such an entity, was relieved by surgical removal of the ossified tissue. Ossification of the pterygomandibular raphe should, in the future, be considered in the differential diagnosis in cases of obscure lateral pharyngeal pain.

The goals of revision total hip arthroplasty (THA) are to reestablish and maintain stable implant fixation. Based upon promising early results in primary THA, porous-surfaced implants designed for bone ingrowth fixation are being increasingly used in hopes of more successfully achieving these goals than has been the case using cement. One hundred and sixty such revisions were followed for a mean of 4.4 years, with specific reference to implant fixation. Roentgenographic evaluation of implant fixation suggested four categories of femoral and acetabular components: (1) bone ingrown, (2) stable fibrous encapsulation, (3) questionable, with signs of impending instability, or (4) definitely unstable implant migration, indicative of the need for rerevision. Not surprisingly, success in achieving and maintaining stable implant fixation following revision THA is dependent upon component design, surgical technique, and preexistent bone stock damage. This classification according to bone stock damage should be borne in mind when critically evaluating the results from various revision series.

A retrospective study of 227 traumatic tympanic membrane perforations was made. These perforations were treated in a clinical practice of otolaryngology between January 1969 and July 1977. The following conclusions were supported by the data obtained: 1. Larger perforations are less likely to heal spontaneously. 2. Lightning and molten metal injuries are less likely to heal spontaneously. 3. Final healing and hearing results are good regardless of the mode of therapy employed. 4. Spontaneous healing gives better results than early surgical intervention. 5. Infection adversely affects healing in traumatic perforations. Based on information delineated in the paper, a logical plan of treatment for traumatic perforations is presented.