Section of Orthopaedics and Sports Medicine, Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden.
Acta Orthop. 2009 Jun;80(3):298-302. doi: 10.3109/17453670903039403.
According to the manual of the cementless Link MP reconstruction prosthesis, a distal femoral stem-bone anchorage of at least 80 mm is necessary to gain implant stability. There have been no in vivo studies showing that this distance is either achieved in clinical practice or needed for clinically satisfying results. Thus, we assessed the femoral stem-bone anchorage of the MP prosthesis using CT.
14 patients with the MP stem were evaluated by CT scans at a median follow-up time of 12 months postoperatively. Femoral stem-bone anchorage was defined as adequate if 50% of the stem flutes or more had cortical bone contact. The length of anchorage was derived from the number of slices with adequate anchorage. Clinical outcome was assessed with VAS for pain and Harris hip score (HHS), both at 1 and 5 years of follow-up.
The median length of stem-bone anchorage was 33 mm (interquartile range 10-60), which was shorter than recommended (p = 0.002). Still, at the 1-year control, all patients were fully weight-bearing and only 1/14 complained about mild thigh pain. 7/14 patients did not experience any pain in the affected hip. The patients had a median of 85 points in the HHS. The clinical outcome at 5 years was unchanged.
We found that it can be difficult to achieve a stem-bone anchorage of at least 80 mm for the MP Link prosthesis. However, this does not appear to be necessary to obtain stability and to achieve clinically satisfying results.
根据 Link MP 非骨水泥重建假体的使用手册，为了获得植入物稳定性，股骨远端柄骨的锚固至少需要 80mm。目前还没有临床研究表明，在临床实践中是否达到了这一距离，或者是否需要达到这一距离才能获得满意的临床效果。因此，我们使用 CT 评估了 MP 假体的股骨柄骨锚固情况。
14 名患者在术后中位随访时间为 12 个月时接受了 MP 假体的 CT 扫描评估。如果 50%或更多的柄槽具有皮质骨接触，则认为股骨柄骨锚固是充分的。锚固长度通过具有充分锚固的切片数量得出。通过疼痛视觉模拟评分（VAS）和髋关节 Harris 评分（HHS）评估临床结果，随访时间分别为 1 年和 5 年。
股骨柄骨锚固的中位数为 33mm（四分位距 10-60），短于推荐值（p=0.002）。尽管如此，在 1 年的随访时，所有患者都完全负重，只有 1/14 名患者抱怨轻微的大腿疼痛。7/14 名患者在受影响的髋关节处没有任何疼痛。患者的 HHS中位数为 85 分。5 年的临床结果保持不变。
我们发现，对于 Link MP 假体，很难达到至少 80mm 的柄骨锚固。然而，这似乎并不是获得稳定性和获得满意的临床效果所必需的。
