The effect of partial fibulectomy on contact pressure of the knee: a cadaveric study.

PURPOSE

The fibula is a valuable source of bone graft and partial or total fibulectomy is done in some procedures, such as upper tibial osteotomy and treatment of tibial nonunion. Previous studies emphasized donor-site morbidity after fibulectomy. The aim of our study was to quantitatively survey joint reaction forces in the medial and lateral compartments of the ipsilateral knee, after partial fibulectomy.

METHODS

Using left knees of six cadavers, after medial and lateral arthrotomy and total meniscectomy, Fuji pressure-sensitive film was inserted to both lateral and medial knee compartments. Weight bearing was simulated using a novel device that allowed a defined axial force to be applied to the left lower limbs of supine cadavers. The axial force of half the body weight of each specimen was applied to the plantar surface of the foot. After removing the films, fibulectomy was done 12 cm proximal to lateral malleolus and 2 cm of fibula harvested. The examination was repeated again in the same manner with new films. The resulting Fuji films were scanned using HP Scanjet (G3110) with resolution of 4,800 × 9,600 dpi. Films interpreted using software for Fuji pressure-sensitive film analysis.

RESULTS

Joint reaction force was decreased in the medial compartment (P = 0.028) and increased in the lateral compartment (P = 0.027) after partial fibulectomy. Our study also showed that pressure changes over the medial and lateral compartments of the knee were not dependent on body weight (P = 0.787 for the medial compartment and P = 0.872 for the lateral compartment) and decreasing pressure in medial compartment was not depended on increasing pressure in lateral compartment (P = 0.208 and correlation coefficient were 0.6).

CONCLUSIONS

The current study demonstrated partial fibulectomy at 12 cm above lateral malleolus results in decreasing pressure in knee medial compartment and increasing pressure in knee lateral compartment. Further studies are needed to evaluate the clinical importance of partial fibulectomy.