Objectives

Metal-on-metal hip resurfacing (MOMHR) is available as an alternative option for younger, more active patients. There are failure modes that are unique to MOMHR, which include loosening of the femoral head and fractures of the femoral neck. Previous studies have speculated that changes in the vascularity of the femoral head may contribute to these failure modes. This study compares the survivorship between the standard posterior approach (SPA) and modified posterior approach (MPA) in MOMHR.

Background:. Modified posterior approach and its effect on stability and functional outcome in total hip arthroplasty. Material & Methods:. A retrospective comparative evaluation was done to assess the functional outcome and rate of dislocation in 233 hips (Group A) operated before 2007 by convention posterior approach and 567 hips (Group B) were operated by modified posterior approach.(2007–2011) In this modified posterior approach technique, 2–3 stay sutures (non-absorbale Nylon) are applied in the piriformis tendon, short external rotator and proximal part of Quadratous muscle. Then a conjoint- myocapsular sleeve is raised by starting cutting (with cautery) linearly over the capsule with adherent fibers of gluteus minimus to piriformis tendon, short rotators and part of quadratus to expose and dislocate the head. After inserting the definite prosthesis, upper part of sleeve (capsule, piriformis tendon) is sutured with same nonabsorbable Nylon at the lower part of tip of greater trochanter by passing through the bone with needle or by drilling the bone; lower part of the sleeve is tied with lateral trochanteric bone. Additional stability to repair was given by closing the tendinous part of the gluteus maximus by horizontal cross mattress sutures up its attachment to the proximal femoral shaft. Results:. All patients underwent cementless total hip arthroplasty; average Harris hip score at minimum 3.1 yr follow was 88.7 in Group B & 85.2 in Group B. Group B had only one dislocation while Group A had 12 dislocations (5%). Conclusion:. This technique provide enhanced stability and improve functional outcome

Modified posterior approach preserving short external rotators would be able to contribute greatly to prevent dislocation after total hip arthroplasty. We modified the posterior approach to the hip by preserving the external rotator muscles in order to enhance joint stability after total hip arthroplasty in patients with osteonecrosis of the femoral head. The aim of the this study was to determine the influence of external rotator preserving posterior approach in primary total hip replacement on early dislocation and clinical outcome. Three hundred sixty-four primary total hip replacements were divided into two groups based on how the external rotators were treated at surgery. External rotator preservation (Group 1, 165 hips) group was compared with reattachment (Group 2, 199 hips) group by evaluating the clinical and radiographic outcome at one year postoperative. Anteversion was significantly less in Group 1 as compared to Group 2 (P < 0.001). There was no significant difference in inclination between the groups (P > 0.05 in all comparisons). No dislocations were found in 165 hips with external rotator preservation whereas dislocations was noted in 11 (3.9%) in Groups 2, respectively. Group 1 had the higher mean Harris hip score (97.2±2.9 points) as compared with Group 2(94.9±3.4). The results of this study showed that external rotators could play an important role in preserving joint stability after total hip arthroplasty in patients with osteonecrosis of the femoral head. It can be implied that this modified posterior approach would be able to contribute greatly to prevention of dislocation, and improve clinical outcome after total hip arthroplasty