[Quality of tibial cementing in total knee arthroplasty: one or two phase cementing of the tibial and femoral implants]. / Qualité du scellement tibial dans les arthroplasties totales du genou: scellement en un ou deux temps des pièces tibiale et fémorale Etude prospective comparative.

PURPOSE OF THE STUDY: When implanting a total knee prosthesis, the tibial component can be cemented either independently in the flexion position by maintaining an axial force on the implant, or simultaneously in extension by applying a compression force on both the tibial and femoral implants after reducing the prosthesis. The purpose of this study was to determine whether the quality of the cementing depends on the method used: independently in the flexion position, or simultaneously in the extension position. MATERIAL AND METHODS: This was a prospective comparative study between two groups of 20 patients assigned alternatively to one of two study arms: Group 2 with a tibial implant cemented independently and Group 1 with a tibial implant cemented simultaneously with the femoral implant. The cancellous surfaces were prepared by irrigation and gravity flow wash-out. Aspiration of the cancellous section surface was maintained until the radio-opaque cement with standard viscosity (CMW3) was inserted. The penetration of cement into the cancellous bone was noted by zone on the postoperative radiographs (seven days and one month). Implant position, presence of early lucent lines and cement debris were noted. Radiographs were taken under fluoroscopic guidance in order to obtain the best image of the joint space and the tibial plateau. RESULTS: Cement penetration into the tibial plateau was significantly more pronounced in Group 2 for zones 1, 2 (p<0.01) and 3 (p<0.05) on the above proof view. Early translucent lines were noted in 15 of 20 knees in Group 1 (p<0.01). Cement debris and microfractures were noted in five knees in Group 1 (one in Group 2). The position of the implants was not affected by the method used for cementing. CONCLUSION: This study demonstrates the theoretical and radiographic interest of cementing the tibial piece independently with the knee in the flexion position for total knee replacement. It is important to apply sustained pressure to obtain good quality cement-bone interpenetration.

Femoral deficiency reconstruction using a hydroxyapatite-coated locked modular stem. A series of 43 total hip revisions.

INTRODUCTION: We report a continuous prospective series of patients operated on for total hip prosthesis femoral component loosening involving a bone defect. Reconstruction was performed using a hydroxyapatite-coated locked modular stem. The study's objective was to assess medium term clinical and X-ray results obtained with this original concept. MATERIALS AND METHODS: The patients included received a REEF (DePuy) femoral implant for aseptic loosening or loosening associated with a periprosthetic fracture. Implantation was systematically accompanied by an extended trochanteric osteotomy (ETO). Patients were followed up prospectively by clinical and X-ray examination. Their loosening was graded at inclusion according to Vives' classification as revised by SOFCOT in 1999. Analysis focused on actuarial implant survivorship, dislocation and the bone/implant interface. RESULTS: Forty-three hips were included: mean follow-up was 58.2 months (12-92) and mean age at surgery was 72.4 years (37-94). The main indications were severe bone loss rated grade III (n=15) or IV (n=16) according to the SOFCOT classification. There was one long-term failure, involving implant fracture secondary to nonunion of the femoral shaft. Mean Postel and Merle d'Aubigné (PMA) clinical assessment score increased from six preoperatively to 14.5 at end of follow-up. X-ray analysis found no stem migration by end of follow-up. There was consistent consolidation of the ETO around the stem, except in one case of stem fracture which evolved into tight nonunion. In terms of metaphyseal integration, five patients showed radiolucency without evolution over follow-up, and eight had severe calcar cortical atrophy at end of follow-up. Mean 5-year actuarial survivorship was 97.7+/-2.3%, with a 2% incidence of dislocation. DISCUSSION: The complications rate was low, and results were comparable with those reported in the literature. The study confirmed the interest of the extended trochanteric osteotomy exposure and the effectiveness of the hydroxyapatite-coated interlocked modular stem concept in the treatment of hip prosthesis loosening with femoral bone loss (involving or not the cortex). On analysis, the one case of failure does not prescribe the surgical technique employed. Implant osseointegration was difficult to analyze. The extent of the surgical approach and of its corresponding sequels, combined with the complexity of adjusting the implant, however, restrict this surgical option indications to level III and IV cases of femoral loosening.

Prevention of dislocation in total hip revision surgery using a dual mobility design.

BACKGROUND: Postoperative dislocation is the commonest complication following revision total hip arthroplasty (THA). HYPOTHESIS AND TYPE OF STUDY: Dual mobility cups are supposed to reduce the risk of THA instability. The present retrospective study tested this hypothesis on revision THAs and also, assessed this design contribution to acetabular fixation longevity. MATERIALS AND METHODS: The series was homogeneous and continuous, comprising a total of 163 revision THAs: 110 of them were bipolar revisions and 53 were restricted to the acetabular component exchange. Mean patient age was 68.7 years (range: 34-92 years). Novae (SERF, Décines) dual mobility cups were used in all cases: 110 cementless cups were used and 53 cups were cemented in a Kerboull reinforcement ring due to severe acetabular bone loss. RESULTS: Mean patients' follow-up (FU) was 60.4 + or - 17.6 months. There were six early dislocations (which were reduced without additional surgery and remained recurrence-free) and two cases of acetabular loosening. The total postoperative dislocation rate at the end of follow-up was 3.7% and the 7-year cup survivorship rate was 96.1% (95% CI: 92.8-99.2%). In revision for aseptic loosening, the instability rate was 2.9%; in the higher instability risk groups (i.e., revision for infection and or recurrent instability) the dislocation rate was respectively 9% and 0%. DISCUSSION: Dual mobility cups provided a dislocation rate of only 3.7% in revision THA, comparable to the one reported with standard implants for primary THA. This kind of cup design is especially suited to deal with high instability risk revision cases, where constrained components are generally recommended. It can also be indicated in cases of aseptic loosening, where it resulted in a 2.9% dislocation rate and only two impending failures of fixation. In terms of mechanical failure rate, these numbers compare well to the ones pertaining to tripolar and constrained implants. These later alternatives remain possible options but are not fully efficient in terms of long-term stability and fixation longevity. LEVEL OF STUDY: Level IV, retrospective or records-based.