ABSTRACT
INTRODUCTION:: Fracture-dislocations of the Chopart or Lisfranc joint line represent rather rare injuries which usually result from high-energy trauma. During the last decade surgical therapy, including open reduction and internal fixation, had been accepted as the best way to achieve an optimum return to function. Repeatedly, it had been stated that anatomical reduction represented the prerequisite for satisfactory results. But nevertheless, despite benign appearances on postoperative radiographs, even disappointing clinical results may occur after this severe type of complex foot injury. In order to get more insight into foot function after Chopart and/or Lisfranc joint trauma and eventually characterize those parameters with most importance for surgical intervention and a non-disturbed gait function, a post-reconstruction study was performed in 25 patients after surgical therapy and definite healing. METHODS:: Twenty five patients were examined clinically according to a standardized protocol 1-8 years after injury and surgical reconstruction and the Maryland Foot Score (100-point rating scale) was calculated from clinical and anamnestic data. Further, standard radiography of the foot was performed. Five patients had suffered from an injury of the midtarsal joints, 11 patients had an isolated injury of the tarsometatarsal joints and 9 patients had a combined injury of both joint complexes. Surgery generally included open reduction and internal fixation employing AO small fragment screws and/or K-wires, sometimes supplemented by an external fixator. Generally, at the time of examination implant removal had been performed, again. Gait function was studied employing an EMED-SF 4 platform integrated into a walkway of 6 m length. Standard parameters were calculated in 9 specific masks employing the Novel-win software. Essentially, an intraindividual comparison with the data from the non-injured extremity was performed. Further, lateral-medial force indices were calculated using Novel-orthopaedics. RESULTS:: Intraindividual comparison of the local impulse distribution pattern correlated considerably well with the total count of the Maryland Foot Score. The mediolateral force index showed that patients with a former lesion of one of the foot columns (medial or lateral) tended to load the non-injured column, mainly. This could also be recognized in patients with apparently good or excellent gait function. The severity of radiographically visible posttraumatic arthrosis obviously did not influence gait function to a major degree, but a loss of length of one of the foot columns following a comminution injury component or a shift of the foot axis either in the horizontal or in the vertical direction demonstrated a substantial influence on gait quality. Due to the limited number of patients, an influence of technical variations of surgical reconstruction could not be demonstrated. CONCLUSION:: As a practical consequence of the presented study it may be concluded that the correct alignment of the foot axes, including a correct length proportion of the medial and lateral foot columns after an injury of the Chopart and/or Lisfranc joints, should represent a major goal of therapy.
