To compare femoral reconstruction using megaprosthesis versus allograft prosthesis composite.

Forty-one consecutive proximal femoral reconstructions with an allograft-prosthesis composite (21 cases) or a megaprosthesis (20 cases) after tumor resection were reviewed in a retrospective study. The following criteria were considered: functional outcome; long term survival; complications. Chi-square test and Wilcox tests were used to compare groups. The medium and long-term survival curves for these reconstructions were made using the Kaplan-Meier standard methods. The failure of prosthesis was defined as revision for mechanical failure (either aseptic loosening or dislocation), for infection or local recurrence. The comparison of the curves was performed using the Log-Rank test.

Infection (10 p. 100) and instability, in both groups, and loosening, in the megaprosthesis group, were the common causes of failure. There was difference between functional results in the two groups (limping and crutches using was more lower in allograft-prosthesis composite group). Survival analysis showed a 5 and 10-year survival of 77 ± 12 p. 100 for the patients with composites. Five and ten - year survival were 73 ± 11 p. 100 and 0 p 100 respectevely 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 allograft composite prosthesis without modification of functional result or symptomatic loosening.

The functional results seem better in the composite group when compared to the megaprosthesis group. Reconstruction of the abductor mechanism is essential to stabilize the prosthesis and to decrease the limp. When the great trochanter cannot be preserved, we used suture of gluteus medius tendon to tensor 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 than massive prosthesis. The rate of infection is similar to other reported series.

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 graft in our series was often concerning with resorption or fragmentation present in six of the eight cases. This radiological appearance is not as yet responsible for any revision or any change in the functional result however it does remain a worry.

Composite reconstructions probably allow a better functional result when considering proximal reconstruction of the femur. The radiological appearance of these allografts in the long term is however worry some without any evidence so far of worsening functional level or any evidence of prosthetic loosening. It would seem to us that the current level of knowledge would advocate the use of massive allografts together with prosthesis. This does seem still to remain the best choice for proximal femoral reconstruction.

Quarante et une reconstructions du fémur proximal, réalisées à l'aide d'une prothèse composite (21cas) (prothèse et allogreffe) ou d'une prothèse massive (20 cas), ont été étudiées afin d'apprécier les avantages respectifs de chaque technique. Les résultats fonctionnels, la survie des reconstructions, les complications et les résultats radiologiques à long terme ont été analysés pour chaque patient. La perte de substance osseuse du fémur proximal ayant motivé la reconstruction était une résection pour tumeur dans tous les cas.

Le résultat fonctionnel dans le groupe des prothèses composites était sensiblement meilleur (moins de boiterie et recours à une canne moins fréquent). Cette différence était à la limite de la significativité pour l'utilisation d'une canne (p = 0,06) et pour la boiterie (p = 0,08). L'analyse des courbes de survie permettait de mettre en évidence un taux de survie à 5 ans de 77 ± 12 p. 100 pour les prothèses composites et de 73 ± 11 p. 100 pour les prothèses massives. A dix ans, les taux de survie étaient respectivement de 77 ± 12 p. 100 et de 0 p. 100. La différence entre les deux courbes de survie était à la limite de la significativité (p = 0,09).

Une résorption radiologique de l'allogreffe était notée dans plus de la moitié des reconstructions composites sans que cet événement n'entraîne de descellement symptomatique de la prothèse ni d'altération du résultat fonctionnel.

L'utilisation de prothèses composites pour la reconstruction du fémur proximal après résection tumorale reste la solution la plus satisfaisante du point de vue fonctionnel ; cependant, les résorptions de ces allogreffes demeurent préoccupantes pour l'avenir.