Highly porous titanium cup in cementless total hip arthroplasty: registry results at eight years.

PURPOSE: Highly porous cups were developed to improve osseointegration and reduce the rate of aseptic loosening. Highly porous titanium cups could mix the reliability of titanium metal with an enhanced porosity, improving the bony ingrowth. The aim of this report was to assess the survival rates and reasons for revision of a highly porous titanium cup, Fixa Ti-Por (Adler Ortho, Milan, Italy), fabricated using an additive manufacturing. METHODS: The Registry of Prosthetic Orthopedic Implants (RIPO), the Emilia-Romagna region arthroplasty registry, was enquired about cementless cups, implanted since July 2007. Ti-Por cups were compared to all the other cementless sockets, acting as a control group. The survival rates and reasons for revision were evaluated and compared. Comparisons with the same articular couplings were also provided. RESULTS: When all the articular couplings were included, Ti-Por performed better, achieving a statistically higher survival rate than the control group (98.7% vs 97.9%) and a statistically lower incidence of cup aseptic loosening. In case of ceramic on polyethylene couplings, Ti-Por achieved similar survival rate: cup aseptic loosening in Ti-Por group was 0.2%, whereas the control group rated 0.4%. In ceramic-on-ceramic implants, the survival rate was similar in the two groups, Ti-Por achieving a cup aseptic loosening rate of 0.1% (vs 0.14% in the control group). CONCLUSION: Highly porous titanium cups showed trustworthy results at eight years, reducing the rate of aseptic loosening. Longer follow-ups, ion analyses, and pre-clinical in vivo studies would be helpful to better define the reliability of these devices and their advantages.

Long-term results of total hip replacement in patients with Legg-Calvé-Perthes disease.

BACKGROUND: Total hip replacement in patients with Legg-Calvé-Perthes disease can be difficult because of the multiplanar deformities of the proximal part of the femur and previous surgery during childhood. The aim of the present study was to assess the long-term outcomes of total hip replacement in patients who had Legg-Calvé-Perthes disease during childhood. METHODS: A retrospective study was carried out to assess the results of thirty-two total hip replacements that had been performed for twenty-seven patients from January 1989 to November 2004. The average age at the time of surgery was 37.8 years. The average duration of follow-up was 124 months (range, fifty-eight to 248 months). All but one of the implants were cementless. RESULTS: There was only one failure in the present study; specifically, the one cemented stem in the study failed two years after surgery. The cumulative survival rate at fifteen years was 96.9% (95% confidence interval, 90.8% to 100.0%). The overall rate of complications was 12.5%, with two permanent sciatic nerve palsies. At the time of the latest follow-up, the average Harris hip score was 87.5 (range, 73 to 96), which was a marked improvement in comparison with the preoperative score (average, 50.1; range, 25 to 75). CONCLUSIONS: Despite the high rate of neurological complications, possibly related to excessive limb lengthening or inadequate soft-tissue release, total hip replacement can be considered a feasible option for patients with Legg-Calvé-Perthes disease. Careful preoperative planning is advisable in order to overcome the technical pitfalls related to the abnormal proximal femoral and acetabular anatomy of these patients.

Modular neck prostheses in DDH patients: 11-year results.

BACKGROUND: Total hip replacement in developmental dysplasia of the hip is a demanding procedure and usually requires dedicated devices and special surgical techniques. Nevertheless, the described techniques have shown variable outcomes. The aim of this study was to assess the 11-year outcomes of an off-the-shelf modular neck prosthesis in dysplastic patients and to evaluate the ability of the modular neck system to adequately restore femoral offset, abductor muscles lever arm and leg length. METHODS: We retrospectively evaluated 61 modular neck prostheses implanted in 47 patients between June 1995 and March 2004. The preoperative diagnosis was developmental dysplasia of the hip in all cases. The clinical outcomes were assessed using the Harris hip score and the Western Ontario and McMaster Universities score. The femoral offset, abductor muscles lever arm, height and medialization of the hip center of rotation, and differences in leg length were evaluated on postoperative radiographs. Prosthesis survival was calculated according to the Kaplan-Meier method considering any reason for revision as failure. The average follow-up was 117.2 months (range 57-162 months). RESULTS: The cumulative survival at 11 years was 97.5%. One prosthesis failed 5 years after surgery because of a ceramic liner fracture due to an inappropriate obstetric maneuver during labour. At the latest follow-up the mean Harris hip score was 74.7 (range 23-91). Leg length discrepancy was avoided in the majority of cases; femoral offset was almost always restored. CONCLUSIONS: The results of this series support the use of modular neck prostheses as an effective alternative in the treatment of developmental dysplasia of the hip. The modularity was very efficient in restoring offset, leg length and maintaining stability with a good mid-long-term follow-up. Unlike other proposed surgical techniques, these good results are achievable by a standard surgical technique and with an off-the-shelf prosthesis.