Page 86 - Reconstructive Techniques in Musculoskeletal Tumor Surgery

Chapter 4
Discussion
Periacetabular resection and subsequent reconstructions pose a di cult challenge to orthopaedic oncologists. In this retrospective multicenter study, we aimed to evaluate the short-term clinical results of periacetabular reconstruction with the LUMiC prosthesis after internal hemipelvectomy for a pelvic tumor. We found that this implant is associated with a low risk of mechanical failure at short-term follow-up. Nevertheless, these complex reconstructions were associated with a considerable risk of complications, most notably infection.
Our study has a number of limitations. Follow-up duration was limited and longer-term follow-up certainly will be needed to make any claims about intermediate- and long-term durability of this new implant. We tried to compensate for this by performing a multi-institutional study to increase our numbers. Also, we included heterogeneous diagnoses in this study. However, patient numbers are limited and we mainly focus on the reconstruction itself rather than on oncologic outcome. In addition, as a result of the multicenter design of this study, di erent surgical techniques and treatment protocols have been used. A considerable number of surgeons have operated on our patients and results may have been subject to learning curves. Surgeons involved in the care of the patients were involved with data collection and reporting, which may in uence the reporting of complications. We however chose to report on hard endpoints and thereby reduced the risk of assessor bias. Unfortunately, the cumulative incidence plot for implant failure does not show a clear plateau phase and further failures may be expected. We will continue to follow our patients to ascertain the role of the LUMiC in the longer term. Also, we had MSTS functional data on half of our patients, so it is possible that we have overestimated the function we might have seen if we had MSTS scores on all of the patients.
Dislocation rates were dissatisfying in the early period of our study. We were able to improve this by introducing dual-mobility articulation (one single dislocation in 24 dual-mobility cups [4%]). The results obtained with dual-mobility cups compare favorably with results previously obtained with the pedestal cup prosthesis (16% recurrent dislocations, 11% single dislocation)9 and with most other reports on periacetabular reconstruction (12% – 24%)6, 13, 17, 18, 25, 26. Two previous authors reported comparable dislocation rates (3% – 4%)14, 16. Our results suggest that that dual-mobility articulation may be useful for treating instability around the hip, a nding that has been reported elsewhere27. Currently, we use
84