Hip-Knee-Ankle Radiographs Are More Appropriate for Assessment of Post-Operative Mechanical Alignment of Total Knee Arthroplasties than Standard AP Knee Radiographs.

Weight-bearing hip-knee-ankle (HKA) radiographs are the gold standard for measuring lower limb alignment after total knee arthroplasty (TKA), however the majority of UK units use standardised anteroposterior (AP) knee radiographs. This study aimed to determine whether standardised AP knee radiographs adequately assess lower limb alignment after TKA. HKA radiographs from 50 post-operative TKAs were cropped to the size of a standardised AP knee radiograph allowing comparison of mechanical and anatomical alignment measurements between the two views. Repeatability of alignment measurements was significantly better for HKA radiographs, however, there was poor agreement of the mechanical alignment measured between the two views. Standardised AP knee radiographs are insufficient to assess the mechanical alignment of post-operative TKA and we recommend routinely using HKA radiographs.

Proximal femoral resection-interposition arthroplasty in cerebral palsy.

Hip dislocation is common in children with total body cerebral palsy. It is associated with pain, difficulty in seating and problems with perineal hygiene. We present a retrospective study of 15 patients who had undergone 21 proximal femoral resection-interposition arthroplasties between 1990 and 2005. The mean age at the time of surgery was 16.2 years (range 11-26 years). Mean follow-up was 3.4 years (range 1-7 years). Ninety percent of patients had pain relief. Perineal hygiene and sitting was improved in all cases. A lateral femoral head defect was noted in 90% of hips and was associated with pain, and significant degenerative changes. Twelve hips had heterotopic ossification (11 type-1, one type-2 and 0 type-3). No major complications were seen. We would submit that proximal femoral resection is a good salvage procedure for the painful, dislocated hip, with an excellent chance of resolving symptoms. The finding of a lateral femoral head defect on the radiograph is associated with significant degenerative changes.