ABSTRACT
AIMS: With increasing burden of revision hip arthroplasty (THA), one of the major challenges is the management of proximal femoral bone loss associated with previous multiple surgeries. Proximal femoral arthroplasty (PFA) has already been popularized for tumour surgeries. Our aim was to describe the outcome of using PFA in these demanding non-neoplastic cases. METHODS: A retrospective review of 25 patients who underwent PFA for non-neoplastic indications between January 2009 and December 2015 was undertaken. Their clinical and radiological outcome, complication rates, and survival were recorded. All patients had the Stanmore Implant - Modular Endo-prosthetic Tumour System (METS). RESULTS: At mean follow-up of 5.9 years, there were no periprosthetic fractures. Clearance of infection was achieved in 63.6% of cases. One hip was re-revised to pseudo arthroplasty for deep infection. Instability was noted in eight of the hips (32%), of which seven needed further surgery. Out of these eight hips with instability, five had preoperative infection. Deep infection was noted in five of the hips (20%), of which four were primarily revised for infection. One patient had aseptic loosening of the femoral component and awaits revision surgery. The Kaplan-Meier survivorship free of revision of any component for any reason was 72% (95% confidence interval (CI) 51.3% to 92.7%), and for revisions of only femoral component for any reason was 96% (95% CI 86.3% to 105.7%) at five years. CONCLUSION: Dislocation and infection remain the major cause for failure, particularly in patients with pre-existing infection. The use of dual mobility cups, silver-coated implants, and less aggressive postoperative rehabilitation regimens would possibly aid in the reduction of complications. PFA performed in patients with periprosthetic fracture seem to fair better. This study supports the judicious use of PFA in non-oncological revision hip arthroplasties, and that they be performed by experienced revision arthroplasty surgeons. Cite this article: Bone Jt Open 2022;3(3):229-235.
ABSTRACT
BACKGROUND: Surgical techniques and instruments are continuously evolving to improve placement of components in ideal position. We investigated if there is difference in greater trochanter thickness between the stems in satisfactory position and stems in malposition and to assess the ideal thickness of trochanter for femoral stem placement in neutral position as under reaming of trochanter can result in stem malposition. METHODS: Measurement of greater trochanteric thickness in 95 hip replacements (posterior approach) was performed by a junior doctor and two hip fellows using the trauma CAD/PACS software. The stem was considered neutral if the central axis of femur passes through the distal tip of stem in AP and in varus if the tip of stem was lateral to the femoral shaft axis. RESULTS: 79 patients had stem in satisfactory position and 16 patients in varus malposition. Mean trochanteric thickness was 12.6 mm (+/-0.56 mm 95%CI, Median 12.5 mm, SD 2.5 mm) in neutral stems while mean thickness in the varus stem was 18.4 mm (+/-1.01 mm 95%CI, Median 17.8 mm, SD 2 mm). There was statistical significant difference between both groups with p< 0.0001 with intra-observer correlation at 99% between the senior personal while correlation was at 80% between the senior personnel and junior doctor. No statistically significant difference was noted in measurements between the senior personal. CONCLUSIONS: The study confirms the significant difference in greater trochanteric thickness between the well aligned and misaligned femoral components. The study raises the possibility that trochanteric thickness can be used as an accessory surgical aid to check if sufficient broaching has been done laterally to allow the stem to be seated in neutral position with an ideal remnant thickness of 12.5 mm. A surgical instrument can be developed to measure the intraoperative thickness of the trochanter which can be a useful tool for young hip surgeons for better placement of components.
