Introduction

Subchondral insufficiency fractures of the femoral head (SIFFH) occur with normal or physiological stress in patients with poor bone quality. We evaluated the clinical characteristics of SIFFH.

Introduction To acquire high flexion has been a current topic in TKA. However, there is concern about the trade-off between high flexion and safety. The purpose of this study was to determine the factors contributing to the high rate of aseptic loosening in femoral components of LPS-flex TKAs that we experienced.

Materials and Methods: From March 2003 to September 2004, 72 consecutive TKA were performed in 47 osteoarthritic patients by a single surgeon. The high-flex design fixed total knee prostheses (NexGen LPS-Flex) were used in all knees. The weight-bearing high flexion activities such as squatting were permitted as tolerable. We retrospectively analyzed the clinical and radiological outcome of this case series.

Results: At a mean of 32 months (range, 30 to 48 months), 27 (38%) cases had shown the radiological findings of aseptic loosening around the femoral components and fifteen (21%) cases have been revised for the progression of component loosening and pain. Postoperatively, the average maximal flexion was 136º in the loosening group, which was higher than 125º in the no-loosening group (P=0.022). The percentage of patients who could squat, kneel or sit cross-legged postoperatively was greater in the loosening group (85% versus 44%) (P=0.001). The femoral component demonstrated movement into flexion, from a mean of 4° to a mean of 7° (γ angle) in the loosening group and not in the no-loosening group.

Conclusion: The high-flex implant allowed for greater range of motion and high-flexion activities, and however, showed high rate of early femoral component loosening, which was associated with weight-bearing high-flexion activities.

For successful long-term result of non-cemented total hip arthroplasty (THA), direct biological bond between bone and implant through bony ingrowth into the implant is essential. To facilitate strong bond between bone and implant, hydroxyapatite (HA) or hydroxyapatite and tricalcium phosphate (HA-TCP) coated implants have been developed. Early clinical results of HA coated implants were reported very satisfactorily. However, the long-term effects of HA or HA-TCP coating on implants were still controversial. We evaluated the effect of hydroxyapatite and tricalcium phosphate (HA-TCP) coating on fibermetal coated femoral stem. 37 cases using fibermetal coated femoral stem with additional HA-TCP coating and 38 cases using fibermetal coated femoral stem without additional HA-TCP coating were included with average follow-up for 127 months. The mean Harris hip score at final follow-up 91.2 in HA-TCP group and 90.5 in porous group. Engh’s score at final follow-up was 19.1 in HA-TCP group and 18.7 in porous group. Six acetabular components (8.0%, 3 cases in each group) were revised for excessive PE liner wear and liner dissociation from locking mechanism. One femoral stem without HA-TCP coating was considered as a loosening and failure. None of the remaining femoral components (98.7%) showed any signs of aseptic loosening. No significant differences between two groups were found in all parameters. A cement-less porous coated femoral stem provided good clinical function and survival in the medium term regardless of additional HA-TCP coating.

Background: Ceramic-on-ceramic couplings are an attractive alternative bearing surfaces to eliminate or reduce problems related to polyethylene wear debris. Past disappointing experiences with alumina ceramic bearings have led to many improvements in the manufacture and the design of ceramic implants. The purpose of this study was to report the results of contemporary alumina-on-alumina total hip arthroplasties (THAs) with regard to wear, osteolysis, and fracture of the ceramic after a 10-year minimum follow-up.

Methods: We evaluated the results of a series of 66 primary alumina-on-alumina THAs with a metal-backed socket and a cementless stem in 59 patients. All of the patients were 64 years old or younger (mean, 42 years), and a single surgeon performed all of the procedures. They were evaluated clinically and radiographically at the 120 to 126 months follow-up (average, 123 months). During the follow-up, special regards were addressed to wear, periprosthetic osteolysis and ceramic failure.

Results: During the follow-up period, two patients (two hips) had died with the prosthesis in situ as the result of an unrelated medical condition. The mean Harris hip score was 94 points at the latest follow-up evaluation. All of the prostheses had radiographic evidence of a bone ingrowth. No implant was loosened radiographically and no implant was revised. Ceramic wear was not detectable in the 28 hips where differentiation of the femoral head from the cup was possible on radiographs. Periprosthetic osteolysis was observed in no hip. A fracture of the alumina femoral head and a peripheral chip fracture of the alumina insert occurred in one hip following a major motor vehicle accident. A periprosthetic femoral fracture, which required open reduction and internal fixation with metal cables, had occurred in one hip. This fracture healed without problem.

Conclusion: The results of contemporary alumina-on-alumina THAs with a metal-backed socket and a cementless stem were encouraging after a minimum follow up of 10 years. We believe that these improved alumina-on-alumina bearing implants offer a promising option for younger active patients.

We have examined the results obtained with 72 NexGen legacy posterior stabilised-flex fixed total knee replacements in 47 patients implanted by a single surgeon between March 2003 and September 2004.

Aseptic loosening of the femoral component was found in 27 (38%) of the replacements at a mean follow-up of 32 months (30 to 48) and 15 knees (21%) required revision at a mean of 23 months (11 to 45). We compared the radiologically-loose and revised knees with those which had remained well-fixed to identify the factors which had contributed to this high rate of aseptic loosening.

Post-operatively, the mean maximum flexion was 136° (110° to 140°) in the loosened group and 125° (95° to 140°) in the well-fixed group (independent t-test, p = 0.022). Squatting, kneeling, or sitting cross-legged could be achieved by 23 (85%) of the loosened knees, but only 22 (49%) of the well-fixed knees (chi-squared test, p = 0.001). The loosened femoral components were found to migrate into a more flexed position, but no migration was detected in the well-fixed group.

These implants allowed a high degree of flexion, but showed a marked rate of early loosening of the femoral component, which was associated with weight-bearing in maximum flexion.