Session X1I - Foot and Ankle
An Alternate Approach to the Lisfranc Region: An Anatomic and Clinical Study
Introduction: The most common surgical approach to the tarsometatarsal (TMT) joints is a longitudinal incision in the first intermetatarsal space with a second lateral incision over the fourth metatarsal as needed. This incision is directly over the dorsalis pedis artery and the medial cutaneous branch of the deep peroneal nerve with complications including neuroma and vascular insufficiency. We present an alternate incision lateral to the second metatarsal. Anatomic and prospective clinical studies were performed to evaluate this approach.
Methods (Anatomic Study): 26 adult embalmed cadaveric feet were dissected using the standard approach in the first intermetatarsal interval and the alternate incision located along the lateral aspect of the second metatarsal base. The superficial peroneal nerve, the deep peroneal nerve, and the dorsalis pedis artery and its branches were identified. Distances from the incisions to the neurovascular structures at the TMT level were made for both approaches.
Results (Anatomic Study): The distances from the incisions to the anatomic structures at risk are:
| Standard Approach | Alternate Approach | |||||
| Deep Artery | Lateral Branch a. | DP Nerve | Deep Artery | Lateral Branch a. | DP Nerve | |
| Average ± SD (mm) | 1.4 ± 1 | 1.5 ± 0.9 | 2.7 ± 2.4 | 13.9 ± 2.1 | 13.7 ± 2 | 12.6 ± 2.5 |
The standard approach over the first metatarsal interval was much closer to all neurovascular structures than was the alternative incision (P<0.05). There were branches of the superficial peroneal nerve directly in line with both incisions, placing its smaller divisions and branches at risk with both.
Methods (Clinical Study): 42 consecutive patients (average age, 33 years; 23 male, 19 female) with displaced tarsometatarsal (Lisfranc) injuries were managed operatively through the described alternate surgical approach. The technique includes a longitudinal incision over the lateral aspect of the second metatarsal for access to the second and third TMT joints. The fifth TMT joint was stabilized percutaneously if unstable. A second incision was placed medially over the first TMT joint for reduction and fixation of this joint when needed. There were 35 homolateral injuries23 including the second through fifth and 12 including the first through fifth TMT jointsand 7 more limited injuries: 2 isolated second, and 5 second through third TMT joints. 32 of 42 injuries had associated fractures of either the base of a MT or a cuneiform. Each injury was reduced and fixed using 3.5-mm position screws from the second MT base to the middle cuneiform. Additional fixation in the third and fifth TMT joints was used as needed (37/42). The first MT was reduced and fixed via a small direct medial incision if instability existed after the lateral four MTs were stabilized (9 cases).
Results (Clinical Study): All joints were reduced with <2 mm of residual displacement. Screws were left in place a minimum of 4 months and removed in 27 patients. We attempted to defer weight bearing for 3 months. 33 patients were followed for an average of 2.3 years. Radiographic examinations confirmed no loss of reduction in any patient, but significant arthrosis was seen in 8 patients, all associated with fracture dislocations. The average AOFAS score was 79 (range, 67 to 97). Most patients complained of a stiff foot that was not relieved by hardware removal. All but one patient returned to their preinjury employment. There were no cases of injury to the dorsalis pedis artery and no sensory deficits in any patient in the series. One patient developed mild RSD that resolved with therapy and neurontin.
Conclusions/Clinical Relevance: We describe an alternate approach to the TMT region allowing for direct reduction of the second and third TMT joints and visualization of the first TMT joint. The technique reduces the risk to the dorsalis pedis artery and the deep peroneal nerve based on the anatomic study. With the addition of a percutaneous screw in the fifth TMT joint and a small incision medially, all patterns of injury can be managed without two dorsal incisions thus minimizing neurovascular risk. We recommend this approach for TMT injuries.