Despite the multiple patho-aetiological basis of Hallux valgus (HV), corrective osteotomy is a common and globally performed orthopaedic procedure. Over-correction of the inter-metatarsal angle (IMA), however, is not without consequence. Through increased joint pressures, over-correction may predispose to joint degeneration. Hypothesizing that over-correction leads to an increase in intra-articular joint pressures, we constructed a mechanical simulation of the 1st metatarsal-phalangeal joint. The vector forces of Flexor Hallucis Longus, Extensor Hallucis Longus, Extensor Hallucis Brevis and Adductor Hallucis, acting upon the 1st proximal phalanx were simulated with tensioned weighted rope. A Foley catheter balloon inflated to 1.5ml, simulated intra-articular distractive vector forces. The joint was freely mobile. At 5° IMA intervals from 10° valgus to 15° varus, intrarticular pressures were recorded using a contact pressure (Graseby™, Introduction
Methods
286 patients underwent total hip arthroplasty with a cemented titanium femoral implant (Ultima, Johnson & Johnson) between July 1995 and July 2001. The acetabular component was either a porous coated cup or a cemented all-polyethylene cup. A 28mm cobalt chromium head was used in all patients. Patients were prospectively evaluated with clinical examination, Harris hip scores and radiographic assessment. Analysis of the data was performed. Of the 286 patients, 11 patients were excluded from analysis for reasons including incomplete data (8) and death (3). The remaining 275 patients were comprised of 118 males and 157 females with an average age of 70.8 years (55–89 years). The average follow up was 10.5 years (1.03–14.23). The median follow up was 10 years. 177 cemented all-polyethylene and 98 porous coated acetabular cups were used. The average Harris hip scores were 34.4 and 81.25 for preoperative and last follow up visit respectively. 11 stems were revised (aseptic loosening 9, infection 2). Radiographic assessment showed vertical subsidence in 30 patients (10.9%) (>5mm in 6 and < 5mm in 24 patients). Complete cement-bone radiolucency was noted in 11 stems (4%). Radiolucent lines covering < 50% of cement-bone interface were noted in 18 stems (6.5%). There were no cases of cement fracture. Kaplan-Meier survivorship was 91% at 10 years & 89.8% at 12 years.Method
Results
