Page 73 - Reconstructive Techniques in Musculoskeletal Tumor Surgery

LUMiC
joint was preserved; alternative treatments included hip transposition and saddle or custom-made prostheses in some of the contributing centers; these were generally used when the medial ilium was involved in the tumorous process or if the LUMiC was not yet available in the speci c country at that time. Conventional chondrosarcoma was the predominant diagnosis (n = 22 [47%]); ve patients (11%) had osseous metastases of a distant carcinoma and three (6%) had multiple myeloma. Uncemented xation (n = 43 [91%]) was preferred. Dual-mobility cups (n = 24 [51%]) were mainly used in case of a higher presumed risk of dislocation in the early period of our study; later, dual-mobility cups became the standard for the majority of the reconstructions. Silver-coated acetabular cups were used in 29 reconstructions (62%); because only the largest cup size was available with silver coating, its use depended on the cup size that was chosen. We used a competing risk model to estimate the cumulative incidence of implant failure.
Results: Six patients (13%) had a single dislocation; four (9%) had recurrent dislocations. The risk of dislocation was lower in reconstructions with a dual- mobility cup (one of 24 [4%]) than in those without (nine of 23 [39%]) (hazard ratio, 0.11; 95% CI, 0.01 – 0.89; p = 0.038). Three patients (6%; one with a preceding structural allograft reconstruction, one with poor initial xation as a result of an intraoperative fracture, and one with a cemented stem) had loosening and underwent revision. Infections occurred in 13 reconstructions (28%). Median duration of surgery was 6.5 hours (range, 4.0 – 13.6 hours) for patients with an infection and 5.3 hours (range, 2.8 – 9.9 hours) for those without (p = 0.060); blood loss was 2.3 L (range, 0.8 – 8.2 L) for patients with an infection and 1.5 L (range, 0.4 – 3.8 L) for those without (p = 0.039). The cumulative incidences of implant failure at 2 and 5 years were 2.1% (95% CI, 0 – 6.3) and 17.3% (95% CI, 0.7 – 33.9) for mechanical reasons and 6.4% (95% CI, 0 – 13.4) and 9.2% (95% CI, 0.5 – 17.9) for infection, respectively. Reasons for reconstruction failure were instability (n = 1 [2%]), loosening (n = 3 [6%]), and infection (n = 4 [9%]). Mean MSTS functional outcome score at follow-up was 70% (range, 33%–93%).
Conclusions: At short-term follow-up, the LUMiC prosthesis demonstrated a low frequency of mechanical complications and failure when used to reconstruct the acetabulum in patients who underwent major pelvic tumor resections, and we believe this is a useful reconstruction for periacetabular resections for tumor or
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