A comparison of acetabular impaction grafting and trabecular metal for revision arthroplasty.

BACKGROUND: Acetabular defect reconstruction in revision hip arthroplasty may be achieved with acetabular impaction bone grafting (AIBG) or porous trabecular metal (TM) implantation. We sought to compare clinical and radiological outcomes of both methods at a single institution. METHODS: 36 patients that were revised using AIBG and 17 patients that were revised with TM were retrospectively reviewed from local joint registry data. 82% of the TM group and 64% of the AIBG group were ≥ Paprosky 2c. Rerevision was considered failure. Radiographs demonstrating 5 mm of migration of femoral head and 5° of acetabular component inclination change were considered loose. RESULTS: Age at surgery was earlier in the AIBG group (median 68 years vs. 74 years). Median follow-up was 5.9 years for AIBG and 5.4 years for TM. Harris Hip Scores improved significantly for both groups (mean improvement: 32 vs. 31). There were 4 failures (11%) in the AIBG group and none in the TM group. 3 of the 4 AIBG failures occurred following second-stage revision for prosthetic joint infection. 4 (11%) and 2 (12%) hip reconstructions demonstrated radiological evidence of loosening in AIBG and TM groups respectively. CONCLUSIONS: AIBG and TM acetabular defect reconstructions achieve good clinical outcome but there is greater success with TM in higher grades of acetabular deficiency regardless of prior infection.

Synchronous quadriceps tendon rupture and unilateral ACL tear in a weightlifter, associated with anabolic steroid use.

Synchronous quadriceps tendon rupture is rare. A 29-year-old man, an amateur weight lifter, taking androgenic-anabolic steroids (AAS), developed sudden onset bilateral pain and swelling of his anterior thighs when attempting to squat 280 kg (620 lb). Examination revealed gross swelling superior to the patella and palpable gaps in both quadriceps tendons. He underwent successful operative repair. MRI revealed a partial tear of the anterior cruciate ligament (ACL) of the right knee. This was not reconstructed. Only a few case reports of the association between AAS and quadriceps rupture exist in the literature, with none to the best of our knowledge in the past 10 years. ACL rupture coexisting is very rare, with only two reported cases.

The significance of hand dominance in hip osteoarthritis.

OBJECTIVES: Hip arthroplasty registries, encompassing all-cause end-stage hip degeneration, have shown that slightly more right hip replacements are performed than left. Given that greater than 85% of individuals are right-handed, we sought to investigate the association between side of hand dominance and side of hip osteoarthritis. METHODS: This Level III observational study evaluated exclusively end-stage osteoarthritis of the hip, using 3 independent centres totalling 386 consecutive arthroplasty patients. Logistic regression was used as a statistical model. RESULTS: In total, 322 patients with hip osteoarthritis were included in the final analysis, including 146 (45.5%) women and 176 (54.5%) men, with a mean age of 68.1 years (SD = 9.5 years). There were 133 (41.2%) right, 73 (22.6%) left, and 116 (35.9%) bilateral hips where the contralateral side had been previously replaced. The proportion of individuals requiring unilateral hip arthroplasty on their dominant side was 67.4%. CONCLUSIONS: In the development of hip osteoarthritis, one is significantly more likely to require hip arthroplasty on their dominant side than in the contralateral hip. Assessment of hand dominance identifies cerebral laterality as a contributing factor in predisposing one's dominant side to hip osteoarthritis.

Optimizing the fat and water content of impaction bone allograft.

Fresh morselized impacted bone graft usually fails due to shear forces. The presence of fat, water, and marrow particles act as interparticle lubricants, reducing the interlocking of particles and allowing the graft to move more freely. Furthermore, the presence of this incompressible fluid damps and resists compressive forces during impaction, preventing the graft particles from moving into a closer formation. We believe there exists an ideal concentration of fat and water that will maximize resistance to shear forces. We performed mechanical shear testing in vitro on morselized human femoral heads, varying the amount of fat and water to determine their optimum concentrations. Level of fat and water were determined that increased strength by 36% over unaltered bone graft. This is most closely approximated in an operating room by washing and subsequently squeezing the bone graft. Optimizing the fat and water content of bone graft produces a stronger graft that is more resistant to shear stresses, protecting the surgical construct until bone growth can occur.

Two-stage revision of infected hip arthroplasty using a shortened post-operative course of antibiotics.

INTRODUCTION: We present a series of 30 consecutive patients with 31 infected total hip arthroplasties treated by a single surgeon over a 4-year period in whom a shortened post-operative course of antimicrobial chemotherapy was used. METHODS: The treatment protocol consisted of a two-stage exchange with removal of infected components, insertion of an interim antibiotic eluting cement spacer and re-implantation of an extensively coated uncemented prosthesis on the femoral side. Systemic antibiotic treatment following each stage consisted of an abridged course of 5 days post-operative intra-venous administration followed by complete cessation of anti-microbial therapy. RESULTS: At a mean follow-up of 35 months (minimum 24 months), there were no cases of recurrent prosthetic infection and no patient had required revision for aseptic loosening or mechanical instability on the femoral side. The combination of effective-staged surgical joint debridement, a shortened post-operative course of systemic antibiotic treatment and an adequate latent period before re-implantation has led to encourage early results in this series of revised chronic hip joint prosthetic infections.

The 22-mm vs the 32-mm femoral head in cemented primary hip arthroplasty long-term clinical and radiological follow-up study.

A retrospective clinical and radiological analysis was performed on 117 patients (138 hips) with a mean age of 75 years and a mean follow-up of 11 years. The prostheses used were 2 similar monoblock femoral components with 22- and 32-mm head sizes; their effects on the wear of the high-density polyethylene cup were studied. Wear of component was determined by evaluating the standardized initial and follow-up radiographs. The mean rate of linear wear was higher in the 22-mm femoral head, whereas the volumetric wear was higher in the 32-mm femoral head. In both groups, volumetric wear was significantly correlated with cup lysis. Increasing body weight in both groups was associated with more volumetric wear. The radiological evidence of prosthetic loosening did not correlate well with clinical evaluation of the hip.