Abstract
Although many patients will do relatively well following hallux valgus surgery, complications will occur despite our best efforts. Consideration must be given the metatarsophalangeal joint itself and determine whether joint salvage is possible or is an arthrodesis the most appropriate choice. In cases of joint salvage, a logical approach is presented in this chapter.
Key Words
nonunion, malunion, hallux valgus, revision
General Principles of Managing Complications
As the saying goes, the best way to treat a complication is to avoid one to begin with, and this applies in particular to correction of hallux valgus, for which many treatment approaches carry an increased risk of failure. Some very simple principles or rules should be followed in planning hallux valgus surgery. The presence of soft tissue problems, including scarring, contracture, and neuritis, must be taken into consideration with any revision of forefoot procedures. Unfortunately, further scarring and stiffening at the metatarsophalangeal (MTP) joint is likely with many revision metatarsal procedures. Regardless of the bone correction and the ultimate alignment obtained, the potential for failure because of stiffness of the MTP joint must be considered. Stiffness of the MTP joint is generally global and therefore includes not only the joint and capsule, but also the sesamoid sling and the flexor brevis muscles and ligaments attaching to the proximal phalanx. Although healed bones and improved alignment are worthwhile goals, the potential for worsening of any scarring, neuritis, and stiffness of the MTP joint must be a primary consideration.
Because of this concern, arthrodesis is an appealing choice for some revision procedures and should not be considered only as a “last resort.” This is particularly the case when the deformity and disease involve the MTP joint only ( Fig. 4.1 ). If the hallux interphalangeal (IP) joint is contracted or deformed, then MTP arthrodesis may not be the preferred procedure.
In any case, the following general principles should be addressed in surgical planning:
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Do not overextend the indications for a procedure.
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Identify deformity of the metatarsal in more than one plane, particularly pronation of the metatarsal, which is frequently present in the setting of recurrent hallux valgus.
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Be cognizant of the effect of the hallux on the lesser toes, and vice versa ( Fig. 4.2 ).
Figure 4.2
(A and B) Even with optimal correction of the hallux deformity, unless the lesser toes are realigned, recurrent hallux valgus will develop. Abduction of the toes cannot be corrected adequately with soft tissue release only. Shortening of the lesser metatarsals is required.
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Be familiar with the concept of hypermobility and increased motion of the first metatarsal in the sagittal, horizontal, and frontal planes.
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Evaluate the functional status of the sesamoid apparatus and the extrinsic tendons, and identify any contracture of the extensor hallucis longus.
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Avoid incisions that can cause neuroma formation.
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Avoid a dorsal incision, which is associated with increased stiffness of the hallux postoperatively, and in particular, with an inevitable decrease in plantar flexion.
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Maintain an awareness of the blood supply to the first metatarsal.
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Recognize the effect of the hindfoot on the forefoot, because correction of hallux valgus may fail if a flatfoot deformity is present, causing increased pronation on the hallux ( Fig. 4.3 ).
Figure 4.3
(A and B) With hallux valgus associated with a flexible flatfoot deformity, as shown here, surgical correction of the hindfoot must be included in the reconstruction because postoperative recurrence of hallux valgus is otherwise very likely.
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Avascular necrosis (AVN) occurs as a result of excessive stripping of the periosteum—for no other reason. If AVN occurs, too much exposure of the metatarsal was performed; if it occurs more than once in a specific surgeon’s clinical practice, the need for changes in surgical technique should be considered, because something is wrong ( Fig. 4.4 ).
Figure 4.4
(A) Avascular necrosis with hallux varus developed after treatment with a distal metatarsal osteotomy. (B) Treatment was with an arthrodesis, using a structural bone graft to lengthen the avascular shortened metatarsal.
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Fixed pronation of the hallux is generally because of pronation of the first metatarsal in addition to the hallux itself. Correction of the pronation is essential in addition to an osteotomy of the phalanx, which should be considered.
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Recognize the occasional association of hallux valgus with more rigid and arthritic deformity of the MTP joint. The patient will be far happier with a fused MTP joint with a corrected deformity than one that is painful with recurrent hallux valgus ( Fig. 4.5 ).
Figure 4.5
Arthrodesis for correction of hallux valgus is a good option for management of severe deformity, with or without arthritis. (A and B) In these radiographs, the valgus deformity is accompanied by evidence of arthritis.
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A primary arthrodesis for correction of hallux valgus is a good operation. Anticipate the need for arthrodesis in selected patients.
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Because arthrodesis works well for patients with rheumatologic deformity, it undoubtedly merits increased use in corrective foot and ankle surgery. Dislocation of the MTP joint can be realistically corrected only with arthrodesis ( Fig. 4.6 ).
Figure 4.6
(A) Dislocation of the metatarsophalangeal joint seen in this radiograph was not associated with rheumatologic deformity. (B and C) Due to the presence of severe osteopenia, fixation was not possible with screws or a plate, and threaded pins were used for the arthrodesis.
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The lesser toe deformities associated with hallux valgus always require correction, and if abducted or adducted toes are not straightened (generally with shortening osteotomies of the metatarsals), recurrent deformity of the hallux will develop ( Fig. 4.7 ).
Figure 4.7
(A) Although arthritis was not severe, the deformity was significant. (B) The opposite foot had been treated unsuccessfully with a crescentic osteotomy, resulting in recurrence, and an arthrodesis was selected as the ideal procedure for correction of the hallux valgus deformity associated with significant metatarsus adductus.
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A soft tissue release should be performed for many hallux valgus deformities. Although this may not be perceived as necessary with use of a distal metatarsal osteotomy, the results with a distal chevron osteotomy, for example, have been demonstrated to be better when the release is performed. This may be done percutaneously.
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Lengthening the first metatarsal does not make anatomic or biomechanical sense. Increasing the tension on the intrinsic muscles can only increase the likelihood of recurrent deformity or stiffness of the MTP joint. This may be the underlying etiology of why recurrence following a proximal opening wedge osteotomy is high ( Figs. 4.8 and 4.9 ). Combining an opening and distal closing wedge osteotomy for juvenile bunions or in cases with an increased distal metatarsal articular angle (DMAA) is a more appropriate use of this procedure.
Figure 4.8
Patient with moderate hallux valgus (A) that underwent a proximal opening wedge osteotomy. At 3 months, the intermetatarsal angle was felt to be corrected with satisfactory reduction of the sesamoids (B). However, at 6 months, recurrence of deformity with continued and painful stiffness of the hallux is noted (C).
Figure 4.9
Failure to recognize instability and, in some cases, subluxation of the first tarsometatarsal (TMT) following a proximal opening wedge osteotomy predictably leads to recurrence (A). Despite the apparent increase in the distal metatarsal articular angle, this was the result of an increase in pronation of the metatarsal, and all that was required to correct the deformity was a modified Lapidus procedure performed with adequate supination of the metatarsal (B). The forced increase in length with an isolated opening wedge may result in the unusual and unique subluxation of the first TMT that occurs following this operation as noted here with widening between the base of the first and the second.
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For an optimal result, some relaxation of the intrinsic musculature around the hallux should be obtained with correction.
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Fixation should always be stable. Periosteal new bone formation around the osteotomy indicates motion, inadequate fixation, and an increased likelihood of delayed union or nonunion.
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Spasticity, such as that associated with cerebral palsy, does not lend itself to management with osteotomy; an arthrodesis of the MTP joint gives a more reliable result.
Nonunion
Nonunion is generally the result of inadequate fixation, excessive stripping and exposure, or incorrect placement of the osteotomy cut. With any nonunion, an avascular segment of bone at the nonunion interface is likely, with shortening of the metatarsal, but further shortening is also likely once debridement has been performed. Debridement is required to obtain bone bleeding and healing but inevitably leads to further shortening and the likelihood of increasing lateral metatarsalgia. Therefore the approach to correction will depend on the presence of existing metatarsalgia, the amount of shortening already present in the first metatarsal, the presence of any arthritis in the MTP joint, and any associated soft tissue problems.
Accordingly, with repair of a nonunion, the issues are whether a structural bone graft can be used to restore length or whether primary bone healing can be obtained through supplementation of a cancellous bone graft. It generally is easier to obtain fixation of the diaphysis but easier to obtain bone healing in the metaphysis. Nonunion of a distal metatarsal osteotomy is unusual. However, simultaneous repair of the nonunion and adequate fixation of the metatarsal head in appropriate alignment is difficult to achieve.
During the operation, the surgeon must establish the correct length of the metatarsal with a laminar spreader after debridement at the osteotomy nonunion site ( Fig. 4.10 ). In restoring length to the metatarsal, it is important to ensure that too much stress is not present on the hallux MTP joint because this will decrease motion of the hallux considerably. Once we have stretched the metatarsal back out to its appropriate length, multiple Kirschner wires (K-wires) are inserted transversely among the first, second, and third metatarsals to stabilize the first metatarsal in the desired position while fixation options are explored. The same applies to repair of a malunion or nonunion of the metatarsal head after a distal metatarsal osteotomy, although here the risk of stiffness is markedly increased. Salvage of a distal metatarsal nonunion must be considered as an alternative to an arthrodesis. If arthrodesis is performed, however, most of the metatarsal head will need to be excised, and a very large bone graft must be used to restore length. For this reason, we are always prepared to attempt salvage of the distal metatarsal nonunion with restoration of length, and then, if painful arthritis develops, to perform an arthrodesis later on ( Fig. 4.11 ). A more proximal metatarsal nonunion is often the result of inadequate fixation or excessive patient activity in the postoperative period without adequate immobilization. It is important to restore the length of the metatarsal, and as noted earlier, avascular bone is generally present on either side of the osteotomy, necessitating use of a bone graft ( Figs. 4.12 and 4.13 ). Depending on the orientation of the nonunion, a structural bone graft is usually necessary to lengthen the metatarsal. Perhaps these complications can be anticipated if periosteal new bone formation develops in the early postoperative period (see Fig. 4.13 ). This finding is an indicator of excessive motion at the osteotomy, and immobilization may be sufficient at this stage. If the bone heals, it will often do so with some dorsiflexion, and a malunion will be the result. This complication is, however, easier to treat than a nonunion.
