Arthrodesis of the Tarsometatarsal Joint




Abstract


Arthrodesis of the tarsometatarsal (TMT) joint is performed for treatment of arthritis of variable extent with or without deformity, in the setting of idiopathic osteoarthritis or posttraumatic or inflammatory arthritis, and for correction of neuropathic deformity. The arthrodesis should be limited to symptomatic joints, which are not always easy to identify. A combination of the location of the patient’s symptoms, the appearance on plain radiographs, and findings on clinical examination will determine the joints to be fused. The radiographic appearance of the lateral column is not always helpful with the decision-making process because the lateral column often is asymptomatic despite the radiographic presence of arthritic changes Instability of the first TMT joint must be addressed despite lack of arthritic changes, in order to restore stability and correct deformity when treating second and third TMT arthritis. All involved segments of the midfoot should be included in the arthrodesis, which often will extend to the naviculocuneiform and intercuneiform. Common to all of these procedures is the need to correct and restore the alignment with the arthrodesis, because the functional results with arthrodesis are far better if the forefoot as well as any hindfoot deformity is corrected. The deformity that commonly accompanies arthritis of the TMT joint is abduction of the forefoot relative to the hindfoot associated with sagittal and coronal plane instability of the first metatarsal. With increasing abduction, the midfoot and forefoot pronate, creating torque on the medial aspect of the midfoot and on the hallux, with resultant hallux valgus. With increasing deformity, additional procedures must therefore be performed to obtain adequate alignment of the foot.




Key Words

arthritis, arthrodesis, midfoot, tarsometatarsal

 




Overview


Arthrodesis of the tarsometatarsal (TMT) joint is performed for treatment of arthritis of variable extent with or without deformity, in the setting of idiopathic osteoarthritis or posttraumatic or inflammatory arthritis, and for correction of neuropathic deformity ( ). The arthrodesis should be limited to symptomatic joints, which are not always easy to identify. A combination of the location of the patient’s symptoms, the appearance on plain radiographs, and findings on clinical examination will determine the joints to be fused. The radiographic appearance of the lateral column is not always helpful with the decision-making process, because the lateral column is often asymptomatic despite the radiographic presence of arthritic changes. Instability of the first TMT joint must be addressed despite lack of arthritic changes, to restore stability and correct deformity when treating second and third TMT arthritis. All involved segments of the midfoot should be included in the arthrodesis, which often will extend to the naviculocuneiform and intercuneiform joints. Such extensive involvement is particularly common with inflammatory arthropathy and after trauma, when arthritis and deformity may include the intercuneiform and naviculocuneiform joints—hence use of the term tarsometatarsal joint complex to designate the relevant anatomy ( Fig. 28.1 ).










Figure 28.1


Combined naviculocuneiform and tarsometatarsal arthritis in a patient with undiagnosed rheumatoid arthritis. Correction required a combined arthrodesis with the use of multiple fixation techniques (A–D). Achieving rigid fixation is difficult given the multitude of joints, and one should have different fixation methods available to achieve stability. In these cases, a combination of screws, plates, and nitinol compression staples were used to achieve fixation. We have noted excellent stability and union with the use of nitinol compression staples for the midfoot.


Common to all of these procedures is the need to correct and restore the alignment with the arthrodesis, because the functional results with arthrodesis are far better if the forefoot as well as any hindfoot deformity is corrected ( Fig. 28.2 ). The deformity that commonly accompanies arthritis of the TMT joint is abduction of the forefoot relative to the hindfoot associated with sagittal and coronal plane instability of the first metatarsal. With increasing abduction, the midfoot and forefoot pronate, creating torque on the medial aspect of the midfoot and on the hallux, with resultant hallux valgus. With increasing deformity, additional procedures must therefore be performed to obtain adequate alignment of the foot.




Figure 28.2


Patient with a chronic Lisfranc injury with significant abduction (A) and collapse of the midfoot (C). Precontoured anatomic plates were used, and use of nonlocking screws in the distal segment help to adduct and plantarflex the medial column. Although the plates do not substitute for proper reduction maneuvers, they do facilitate the process. Postoperatively, note the recreation of the normal longitudinal arch (D) and improvement in the abduction deformity (B).


In some instances, as with a flatfoot deformity associated with hindfoot valgus, the hindfoot deformity is primary and the arthritis of the TMT joint is secondary; nevertheless, the hindfoot deformity must be adequately corrected in addition to the obvious painful focus, which as perceived by the patient may be only the TMT joint ( Figs. 28.3 and 28.4 ). In other situations, the midfoot deformity is clearly primary and the deformity of the hindfoot occurs secondarily, as in the case shown in Fig. 28.5 . In this example, severe dislocation involved the entire TMT joint complex including the lateral column. Although we rarely include the lateral column in the arthrodesis, here the entire midfoot required arthrodesis as a consequence of crushing of the cuboid and lateral foot pain. To correct this rather severe deformity, each joint was first debrided and the lateral contracture was released by lengthening the peroneus brevis tendon. Such severe deformities may also necessitate temporary lengthening of the lateral column with an external fixator, followed by reduction of the medial and middle columns ( Fig. 28.6 ). In the case illustrated in Fig. 28.5 , after complete loosening of each joint was achieved with debridement, the peroneus brevis was lengthened and the external fixator applied. The fixation was then initiated from medial to lateral, commencing with placement of temporary pins and followed by application of a combination of plates.










Figure 28.3


It is not always easy to determine which was the primary problem, that is, commencing in the hindfoot with a fixed valgus deformity, or in the midfoot with abduction of the midfoot, pronation of the midfoot, and a secondary hindfoot valgus. The latter is more likely in this case. (A–C) The clinical images are presented here with midfoot arthritis, and collapse of the midfoot caused the secondary changes in the hindfoot with valgus and continued medial hindfoot collapse. (D) The x-ray with severe abduction of the midfoot must be corrected in addition to the hindfoot valgus deformity, at a minimum with a calcaneus osteotomy, either by lateral calcaneus lengthening or medial translation osteotomy.



Figure 28.4


(A and B) Tarsometatarsal (TMT) arthritis, probably secondary to the hindfoot valgus and abduction deformity. (C and D) Correction was accomplished with a TMT arthrodesis, in addition to a lengthening of the lateral column by means of a calcaneus osteotomy.



Figure 28.5


(A–C) This severe posttraumatic deformity was symptomatic in each of the three midfoot columns. Note the severe abduction of the entire tarsometatarsal joint complex. (D and E) Correction was accomplished with an arthrodesis of all three columns, with complete realignment obtained, and plate fixation.



Figure 28.6


For correction of very severe abduction of the midfoot, temporary lengthening of the lateral column can be achieved by means of an external fixator with pins in the calcaneus and fifth metatarsal. This fixation device can be removed once the reduction is complete and internal fixation is secure.




Deformity Correction Principles


Incision and Exposure


For the middle column arthrodesis (of the second and third TMT joints), use a single dorsal incision placed between the second and third metatarsals. This is because the third metatarsal-cuneiform joint extends farther over toward the midline of the foot than is readily apparent. If the first and second TMT joints are to be fused, either one or two incisions can be used. With minimal deformity, one dorsal incision in the first TMT–second TMT interspace may be used ( Figs. 28.7 and 28.8 ). If, however, both deformity and instability of the medial column are present, then use a separate medial incision for access to permit plantar flexion of the medial column ( Fig. 28.9 ). Also use this incision when an extended navicular cuneiform metatarsal arthrodesis is performed that requires application of a plate from the medial aspect of the foot ( Fig. 28.10 ). The use of two dorsal incisions to access the first, second, and third TMT joints is discouraged, as the skin bridge is minimal and, we feel, has higher associated wound complications ( Figs. 28.11 and 28.12 ).










Figure 28.7


Approximation ( black line ) of the first interspace incision (between first and second metatarsals). (A) Blunt dissection is taken to avoid damage to the superficial peroneal nerve ( black arrow ). The extensor hallucis brevis (EHB) is identified ( black arrowhead ) and the sheath released. The neurovascular bundle lies immediately deep to the EHB. (B) Medial retraction of the EHB allows identification of the neurovascular bundle ( arrow ). (C) Medial retraction of both the EHB and neurovascular bundle allow exposure of the second tarsometatarsal joint. Excessive retraction will damage and possibly tear the first proximal communicating artery (D).



Figure 28.8


Access to the first and second tarsometatarsal (TMT) is best performed by considering each joint a window bound by the neurovascular bundle ( arrow ). Gentle lateral retraction of the neurovascular bundle allows for first TMT exposure (A). Medial retraction will expose the second TMT (B). Final appearance of the neurovascular bundle after fixation denoting that is has been left intact (C).



Figure 28.9


The incisions are determined by the extent of the arthrodesis. (A–C) In this case, because all three columns were included in the arthrodesis, three incisions were used with as large a skin bridge between each as possible.



Figure 28.10


Standard exposure for a first tarsometatarsal (TMT) arthrodesis via a medial approach (A). The anterior tibialis is noted inferior along the proximal aspect of the wound ( white arrow ) and is not typically completely exposed. Dissection is taken from superior to inferior, protecting the tendon. In the setting of an extended first TMT and naviculocuneiform fusion, the anterior tibialis ( white arrowheads ) requires complete exposure (B). A thorough understanding of the tendon anatomy is required to avoid tendon damage during the more limited exposure. Note how the distal aspect of the tendon overlies the plantar first TMT joint and is at risk of transection.



Figure 28.11


Wound complications are not uncommon with a large midfoot arthrodesis, and the small skin bridge is often compromised. In this particular case, local wound care was sufficient to allow healing; however, in some cases, a free tissue flap may be required.



Figure 28.12


The three-incision technique affords ease of access with decreased risk to the neurovascular bundles and wound complications, at the expense of increased number of incisions. Incision placement on a patient undergoing a midfoot fusion (A). Two weeks postoperative appearance of the three incision technique from the dorsal (B), medial (C), and lateral (D) views.


Once the dorsal incision has been deepened through subcutaneous tissue, the branches of the superficial peroneal nerve must be identified and then retracted. A neuroma on the dorsal surface of the foot is intolerably uncomfortable, and formation of these lesions can be avoided. The tendon of the extensor hallucis brevis is used as a guide to the location of the deep neurovascular bundle. Once the tendon is identified, the bundle is seen to lie directly underneath it, and both are retracted medially. The easiest way to retract is to undermine the bundle from the subperiosteal tissue over the second metatarsal and then elevate the flap, which includes the neurovascular bundle, using a large periosteal elevator.


Exposure of the joint is difficult and requires the use of either a lamina spreader or a pin distractor ( Fig. 28.13 ). We prefer the use of a pin distractor, as this minimizes the risk of inadvertent compression of the cancellous bone. Joint preparation can be performed with either an oscillating saw, osteotome/flexible chisel, or burr. We prefer the use of an osteotome/flexible chisel, as this technique minimizes iatrogenic shortening. However, if done carefully, the use of an oscillating saw to remove the subchondral bone only is an effective technique. If the use of a saw is chosen, no tourniquet is used to minimize heat necrosis of the bone ( ). It is important not to remove bone wedges with the joint realignment. Even when associated with severe deformity (e.g., see Fig. 28.5 ), no wedge should be removed, and the reduction is always performed using joint debridement, joint preparation, and then translation of the involved metatarsals without removal of any bone wedges. Perhaps the most important aspect of the joint preparation is aggressive perforation of the joint surface using a 1.5- or 2-mm drill bit, made at 1- to 2-mm intervals across the entire joint surface. We do not like to use a Kirschner wire (K-wire) for this purpose because it seems to cause more bone burning. The problem occurs with preparation of a hard sclerotic joint, which can be associated with posttraumatic or idiopathic osteoarthritis. The second metatarsal in particular can be quite avascular, and once this bone is debrided, the metatarsal shortens, resulting in a large gap in the joint. For this reason, aggressive perforation of the joint surface only is used to create a bone slurry, rather than debridement of the joint below the subchondral bone surface. The third metatarsal usually adheres well to the second metatarsal and will follow the second metatarsal into a corrected position. If the medial and middle columns are fused, then we try to debride the spaces between the first and second metatarsal bases and between the medial and middle cuneiforms and then place a bone graft in this location to further stabilize the arthrodesis. The metatarsals tend to dorsiflex with fixation, because debridement of the joint is frequently performed dorsally only. These are very deep joints, and the entire base of the metatarsal cuneiform joint must be completely debrided to prevent a dorsal malunion of the arthrodesis. Insertion of a smooth lamina spreader into the joint dorsally to visualize the plantar apical surface of the joint, before the arthrodesis is completed, is helpful. Frequently, small bits of bone remain on the plantar surface, which must be thoroughly cleared of such debris ( Fig. 28.14 ). Deformity correction does not only apply to the sequelae of trauma or malunion following attempted arthrodesis. For example, severe metatarsus adductus is associated with TMT arthritis in addition to deformity of the hindfoot where the heel is usually in varus. This example is well presented here in a young woman with severe metatarsus adductus associated with arthritis of the midfoot. When associated with arthritis of the second and third TMT joints, these must be included in the arthrodesis, which must be completely corrected with realignment of the midfoot, which then will correct the hallux valgus and forefoot deformity ( Fig. 28.15 ).


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Apr 18, 2019 | Posted by in RHEUMATOLOGY | Comments Off on Arthrodesis of the Tarsometatarsal Joint

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