Proximal femoral reconstruction with megaprosthesis versus allograft prosthesis composite. A comparative study of functional results, complications and longevity in 41 cases

Purpose of the study To compare femoral reconstruction using megaprosthesis versus allograft pro sthesis composite. Material and methods Forty-one consecutive proximal femoral reconstructions with an allograft-pr osthesis composite (21 cases) or a megaprosthesis (20 cases) after tumor re section were reviewed in a retrospective study. The following criteria were considered: functional outcome; long term survival; complications. Chi-squ are test and Wilcox tests were used to compare groups. The medium and long- term survival curves for these reconstructions were made using the Kaplan-M eier standard methods. The failure of prosthesis was defined as revision fo r mechanical failure (either aseptic loosening or dislocation), for infecti on or local recurrence. The comparison of the curves was performed using th e Log-Rank test. Results Infection (10 p. 100) and instability, in both groups, and loosening, in th e megaprosthesis group, were the common causes of failure. There was differ ence between functional results in the two groups (limping and crutches usi ng was more lower in allograft-prosthesis composite group). Survival analys is showed a 5 and 10-year survival of 77 +/- 12 p. 100 for the patients wit h composites. Five and ten - year survival were 73 +/- 11 p. 100 and 0 p 10 0 respectively for those with megaprostheses. No significant difference was noted between survival of these two groups but a tendancy (p = 0.09). Radiological allograft resorption was noted for more than 50 p. 100 of allo graft composite prosthesis without modification of functional result or sym ptomatic loosening. Discussion The functional results seem better in the composite group when compared to the megaprosthesis group. Reconstruction of the abductor mechanism is essen tial to stabilize the prosthesis and to decrease the limp, When the great t rochanter cannot be preserved, we used suture of gluteus medius tendon to t ensor of fascia lata, which is re-enforced using a piece of biceps femoris. The dislocation rate was approximately the same in our two groups. Several authors reported a lower dislocation rate with composite reconstructions th an massive prosthesis. The rate of infection is similar to other reported s eries. In our study it has been possible to show a tendancy for superior survival of the composite reconstruction. When the review was later than 5 years the radiological appearance of the g raft in our series was often concerning with resorption or fragmentation pr esent in six of the eight cases. This radiological appearance is not as yet responsible for any revision or any change in the functional result howeve r it does remain a worry, Conclusion Composite reconstructions probably allow a better functional result when co nsidering proximal reconstruction of the femur. The radiological appearance of these allografts in the long term is however worry some without any evi dence so far of worsening functional level or any evidence of prosthetic lo osening. It would seem to us that the current level of knowledge would advo cate the use of massive allografts together with prosthesis. This does seem still to remain the best choice for proximal femoral reconstruction.