Scarf osteotomy improves hallux valgus and can be used for deformities with large intermetatarsal angles. It is designed to minimise shortening of the first ray. The aim of this radiographic analysis was to assess the outcome of patients undergoing Scarf osteotomy at the Royal Cornwall Hospital.

The initial 18 consecutive cases performed by the senior author were analysed using the guidelines recommended by the American Foot and Ankle Society. Standardised anterior-posterior radiographs of the foot were compared pre-operatively and at 6 weeks postoperatively. Measurements of the intermetatarsal angle (IMA), hallux valgus angle (HVA), joint congruency angle (JCA), distal metatarsal articular angle (DMAA), sesamoid position and metatarsal length were used to assess any improvement.

The results showed a significant median reduction of the IMA of 70, HVA of 180, JCA of 50, and the DMAA of 30 (all p values < 0.001). The medial sesamoid position in relation to the first metatarsal also improved from a mean value of 2.28 to 1 using the American Foot and Ankle Society grading system. There was no shortening of metatarsal length as measured using the Hardy and Clapham method.

This study shows that the radiographic outcome of Scarf osteotomy at the Royal Cornwall Hospital compares favourably with that found in the literature. It provides effective correction of moderate to large intermetatarsal angles.

Decreased head-neck ratio diameter and component malposition in total hip arthroplasty are factors known to result in impingement, increased rates of dislocation, wear and failure. In addition to these complications, impingement of the femoral neck on the acetabular component of a hip resurfacing may result in femoral neck fracture and loosening of the acetabular component. Little is known regarding the optimum femoral and acetabular hip resurfacing component position to avoid impingement.

In the first part of this study we analysed the radiographic component position of 131 consecutive hip resurfacings. In the second part the effect of three component variables on the range of motion to impingement were analysed using a dry bone model:

Inclination of the acetabular cup

The mean femoral-stem shaft angle in the first part of the study was 138° (range 121° to 158°). The mean acetabular inclination angle was 45° (range 30° to 63°). This wide range in position mirrors that described in the literature. The dry bone study revealed an optimum acetabular cup inclination tending towards 50° and an anteversion of 25°. A large diameter femoral head relative to the femoral neck resulted in a greater range of motion to impingement. A fine balance however exists, to remove a minimum amount of pelvic bone to accommodate a larger acetabular component with an ‘oversized’ femoral component.

The acetabular resurfacing cup positions described allow the greatest range of physiological hip movement. New technology and improvements to existing equipment and techniques will hopefully lead to more accurate placement of hip resurfacing components minimising the risk of impingement and its complications in this high demand group of patients