Can hip anatomy be reconstructed with femoral components having only one neck morphology? A study on 466 hips.

This extensive radiographic study asks if there is a statistical relationship between the size of the stem that will best fit the femur and the vertical and lateral offsets of the reconstructed acetabular center, what is the distribution of vertical and lateral offsets in this large and if there is a statistical difference among surgeons in the planned location of the reconstructed acetabular center. On 466 radiographs, five surgeons separately templated stem size and acetabular cup location. The vertical and horizontal coordinates of the reconstructed acetabulum center were measured relative to the planned position of the stem. We found a strong correlation between the stem size and the average lateral and vertical offsets. Acetabular reaming associated with the anatomic variability of native femoral necks, leads to a span of 36 mm in lateral offset, and a span of 39 mm in vertical offset. Statistically significant differences were also found in the way surgeons plan acetabular reaming.

Prospective study of a cementless, mobile-bearing, third generation total ankle prosthesis.

BACKGROUND: The SALTO total ankle prosthesis is a noncemented mobile bearing anatomic design characterized by dual Ti-HA coating. This study reviews our results with this prosthesis. MATERIALS AND METHODS: Between 2001 and 2007, 413 consecutive SALTO prostheses were implanted in our institution in 215 women and 198 men, aged 57.1 +/- 11.9 years. At the last visit, 401 implants (47% in the left ankle) were available with a mean followup of 29 (range, 1 to 84) months. RESULTS: Based on the results of the 218 patients with at least 2 years of postoperative followup, the 5-year estimated survivorship, with the primary end-point being implant removal, was 86.6% and ranged from 85.1% in patients with post-traumatic osteoarthritis to 95.6% in those with rheumatoid arthritis. The AOFAS score increased from 50.9 +/- 16.8 points preoperatively to 82.2 +/- 14 points at followup (mean difference, 31.1 +/- 1.4, 95% confidence interval (C.I.) for the difference, 28.3 to 33.8, p < 0.001). Visual analog scale for pain decreased from 7.4 +/- 1.1 preoperatively to 2.0 +/- 2.0 postoperatively (mean difference, -5.4 +/- 0.7, 95% C.I. for the difference, -5.6 to -5.2, p < 0.001). Flexion/extension ROM increased from 25.2 +/- 14.1 degrees to 33.1 +/- 13.6 degrees at the last followup visit (mean difference, 7.9 +/- 0.5 degrees, 95% C.I. for the difference, 4.3 to 7.2, p < 0.001), while pronation/supination ROM increased from 23.8 +/- 13.7 degrees to 25.4 +/- 14.5 degrees (mean difference, 1.6 +/- 0.7 degrees, 95% C.I. for the difference, 0.9 to 2.2, p = 0.005). CONCLUSION: The SALTO prosthesis provided good clinical and functional results and we believe helps validate the concept of anatomic replacement.