Background The best method for managing large bone defects during revision knee arthroplasty is unknown. Metaphyseal fixation using porous tantalum cones has been proposed for severe bone loss. Whether this approach achieves osseointegration with low complication rates is unclear.

Wear of highly cross-linked polyethylene is reportedly independent of head size. To confirm that observation we asked in our population whether head size related to wear with one type of electron beam highly cross-linked polyethylene. Of 146 hips implanted, we evaluated complete clinical and radiographic data for 90 patients (102 hips or 70%). The minimum followup was 5 years (mean, 5.7 years; range, 5-8 years). The head size was selected intraoperatively based on the size of the acetabular component and presumed risk of dislocation. Polyethylene wear measurements were performed in one experienced laboratory using the method of Martell et al.There was no hip with pelvic or femoral osteolysis. The median linear wear rate was 0.028 mm/year (mean, 0.04 mm/year), and the median volumetric wear rate was 25.6 mm 3 /year (mean, 80.5 mm 3 /year). Median total volumetric wear was 41.0 mm 3 (mean, 98.5 mm 3 ). We found no association between femoral head size and the linear wear rate, but observed an association between larger (36-and 40-mm) head size and volumetric wear rate and total volumetric wear. Although the linear wear rate of polyethylene was not related to femoral head diameter, there was greater volumetric wear (156.6 mm 3 /year) with the 36-and 40-mm heads. Pending long-term studies of large head sizes, we advise caution in using larger femoral heads in young or active patients and in those with a low risk of dislocation.

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Background Highly crosslinked polyethylene (XLPE) was introduced to decrease periprosthetic osteolysis related to polyethylene wear, a major reason for revision of total hip arthroplasty. However, there are few reports of wear and osteolysis at 10 years postoperatively. Questions/purposes (1) What are the linear and volumetric wear rates of XLPE at 10 to 14 years? (2) What is the relationship among linear wear, volumetric wear, and femoral head size? (3) What proportion of hips developed osteolysis and was there a relationship between osteolysis and femoral head size or polyethylene wear?Methods We evaluated a previously reported cohort of 84 hips (72 patients) with one design of an uncemented acetabular component and one electron beam 10-kGy irradiated and remelted XLPE at a mean followup of 11 years (range, 10-14 years). The choice of femoral head size was based on several factors, including the outer diameter size of the acetabular component implanted, the perceived risk of dislocation (including the history of alcohol abuse and patient age), and liner availability from the manufacturer. The femoral head sizes used were 26 mm in 10 hips (12%), 28 mm in 31 hips (37%), 32 mm in 31 hips (37%), 36 mm in eight hips (10%), and 40 mm in four hips (5%). Measurements of linear and volumetric wear were performed in one experienced laboratory by the Martell method and analyzed using the first-to-last method. Standard radiographs, with additional Judet views, were used to detect periprosthetic osteolysis. Statistical analysis of wear and osteolysis compared with head size was performed. Results For the entire cohort, the median linear wear rate as 0.024 mm/year (95% confidence interval [CI], 0.016-0.030) and the median volumetric wear rate was 12.19 mm 3 /year (95% CI, 6.6-15.7). With the numbers available, we found no association between femoral head size and linear wear rate. However, larger femoral heads were associated with more volumetric wear; 36/40-mm femoral heads had higher volumetric wear (median 26.1; 95% CI, 11.3-47.1) than did 26-mm heads (median 3.1; 95% CI, 0.7-12.3), 28-mm heads (median 12.3; 95% CI, 3.0-19.3), and 32-mm heads (median 12.9; 95% CI, 6.6-16.8; p = 0.02). Small osteolytic lesions were noted in 12 hips (14%), but with the numbers available, there was no association with head size or volumetric wear rates. Conclusions This uncemented acetabular component and this particular XLPE had low rates of linear and volumetric wear. Small osteolytic lesions were noted at 10 to 14 years

Jumbo acetabular components with screw fixation were associated with low rates of infection and loosening after revision total hip arthroplasty and had high survival at fifteen years. Reoperation for wear and loosening increased in the second decade. Dislocation was the most common complication and was significantly associated with smaller femoral head sizes.