Arthrodesis is the standard surgical intervention for end-stage arthritis of the tarsometatarsal (TMT) joints. When nonoperative treatment options fail to provide adequate pain relief and restoration of function, then it is time to consider surgical intervention. Minimally invasive approaches to joint preparation are described in the literature for several different areas of the foot and ankle. Common joints that are prepared for arthrodesis through a percutaneous, minimally invasive and/or arthroscopic technique include the ankle, subtalar, hallux, and transverse tarsal joints. With modern techniques and instrumentation, arthrodesis of the TMT joints can also be achieved through minimally invasive techniques.

Patients with TMT arthritis typically present with pain in the middle of the arch, particularly with pushing off. Patients may recall a prior traumatic injury to the foot, but many patients have primary osteoarthritis or inflammatory arthritis without any specific trauma. The pain is usually reduced in stiffer and more built-up shoes. Some patients may notice a dorsal prominence over the midfoot that makes lacing up shoes or wearing tight shoes painful. Occasionally, patients will report burning pain in the first web space due
to irritation and tenting of the deep peroneal nerve over the dorsal midfoot prominence. If there is significant deformity through the TMT joints, such as in Charcot, patients may note collapse of the medial longitudinal arch and abduction of the forefoot.

The most notable examination finding is dorsal tenderness of the involved TMT joints. With careful palpation, the metatarsal shafts, the five TMT joints, and three naviculocuneiform joints can be separately examined. A “piano key” test can be used to help identify the involved joints. To perform this maneuver, the midfoot is stabilized with one hand, and a metatarsal head is moved dorsally and plantarly to stress the corresponding TMT joint. If this provokes pain, arthritis is likely present. Both the dorsalis pedis and posterior tibial arteries should be palpated to ensure adequate pulses. The dorsalis pedis needs to be identified and avoided during surgery, and the posterior tibial artery may be the only major blood supply to the foot in the event of inadvertent iatrogenic injury to the dorsal artery. Moreover, adequate perfusion is required to achieve arthrodesis whether an open or percutaneous technique is used. The patient should be examined while weight bearing to compare the alignment of the foot to the contralateral side to identify deformity. If there is a history of prior surgery or trauma in the midfoot, the extensor tendons, especially the tibialis anterior, should be palpated to ensure that they can be readily identified and avoided during the placement of the bur. A basic neurological examination should be performed. If there is concern for neuropathy, the foot should be examined with a 5.07 Semmes-Weinstein monofilament to check for protective sensation. Occasionally, percussion over the course of the deep peroneal nerve may produce a Tinel sign with tingling in the first web space.

Weight-bearing three-view radiographs of the foot can reliably demonstrate deformity and osteoarthritis. On the anterior-posterior view, arthritis is indicated with joint space narrowing, subchondral sclerosis, and periarticular cysts. Instability can be demonstrated by widening of the interspace between the first and second metatarsals. The cuneiforms and metatarsal bases are typically closely aligned, and instability can also be seen with step-off between the cortices of the metatarsal base and cuneiform. Because of the coronal-plane midfoot arch, the third TMT joint is often better visualized on the oblique view. On the lateral view, instability of the TMT joints can be demonstrated by dorsal translation of the metatarsal base or widening of the plantar aspect of the TMT joint compared to the dorsal aspect.

Computed tomography (CT) studies, weight bearing if available, may be helpful in the setting of deformity or comminuted fractures in the midfoot or metatarsal bases. CT may also help to identify exactly which joints are involved and should be incorporated into the fusion, which can be challenging using plain films and examination alone.

Magnetic resonance imaging (MRI) can be used to identify a purely ligamentous Lisfranc injury. MRI may also help clarify which joints are arthritic and should be fused, but CT is usually sufficient for this purpose.

The most critical step in preoperative preparation is to identify the joints to be included in the fusion. The physical examination and imaging studies both contribute to decision-making, and advanced imaging should be obtained to help make a final decision if there is any doubt. At the end of the procedure, the foot should be plantigrade with the first metatarsal in line with the long axis of the talus. In many cases, in situ arthrodesis at the TMT joints can maintain an appropriate alignment. In cases with deformity through the TMT joints, preparation of the joint surfaces is often sufficient to allow for reduction of the deformity. In more severe deformities, a wedge resection of the metatarsal base may be necessary to restore alignment and should be planned preoperatively (Figure 13.3).