Rheumatoid hindfoot deformity presents typically with hindfoot eversion, flattening of the longitudinal arch, and abduction of the forefoot. Moderate hindfoot valgus can be adequately corrected with a medial displacement osteotomy of the calcaneus, whereas hindfoot varus can be corrected through a lateral closing wedge or lateral displacement calcaneal osteotomy. More severe deformities can be corrected with triple arthrodesis, which provides excellent pain relief for patients with painful arthritic deformities of the subtalar joints.
Severe valgus or varus deformity of the hindfoot in rheumatoid arthritis (RA) commonly means severe destruction of both the tibiotalar and talocalcaneal joints. When the subtalar joint is not too bad, fusion of the ankle can be sufficient, but often the subtalar joint needs correction as well.
Ankle and talocalcaneal arthrodesis are demanding procedures. Meticulous attention must be given to the handling of soft tissues as well as to correction of the underlying deformity and to appropriate positioning of the foot. 5
Arthrodesis should as a rule be limited to the joints involved with the arthritic process because the rate and severity of progressive adjacent joint degeneration appear related to the number of joints fused initially. 4
Tibiotalocalcaneal arthrodesis by retrograde medullary nail fixation has been reported to be successful, 1,3,8–10 and we have used it as a standard procedure in RA feet with severe hindfoot deformities. In those cases, a lot of bone has to be removed to allow full correction, some of it on the tibial side and some on the talar side. Partial removal of the talar bone is not always sufficient to achieve correction in longstanding cases, and to avoid undue tension of the soft tissues, today, in some cases, we prefer to perform total talectomy and fuse calcaneus directly to the distal tibia.
Combined ankle and hindfoot arthrodeses are sometimes thought of as salvage procedures rather than reconstructions. The technique described here is perhaps more commonly used for salvage of loosened or infected ankle prostheses, but it can also be used to transform a foot that is painful and stiff or unstable in a bad position to one that is pain-free in a more functional position.
Regardless of the number of hindfoot joints fused or the techniques used, the goal is to create of a painless, plantigrade foot capable of weight bearing and being fitted into a shoe.
TECHNIQUE FOR EXTENDED ANKLE ARTHRODESIS WITH PARTIAL OR TOTAL TALECTOMY AND RETROGRADE NAILING
The patient is placed in lateral decubitus position on a radiolucent operating table. The nonoperated extremity is flexed at the hip and knee, permitting intraoperative fluoroscopy in all planes. We use a longitudinal incision over the posterior fibula extending distally by an anterior curving over the sinus tarsi (Fig. 1). The distal 4 to 5 cm of the fibula is then resected with an oblique osteotomy (Fig. 2). The distal tibiofibular syndesmosis is left intact to avoid instability symptoms from the distal fibula. The medial malleolus is similarly obliquely osteotomized through a separate incision (Fig. 3), and the cancellous bone is later used for packing into the defect. In case of valgus deformity, we start with a medial curved incision.
The distal tibial joint surface can now be exposed. The talus is removed partially or totally (Fig. 4), and the tibial and talar/calcaneal bone surfaces are then prepared down to bleeding bone in a congruent fashion. Finally, a 3-cm longitudinal plantar incision is made anterior to the subcalcaneal fat pad and if possible, slightly lateral to the midline of the hindfoot for introduction of a nail of appropriate diameter and length (commonly 12 mm in diameter and 18 cm in length) (Fig. 5). It is important to ream at least 0.5 mm larger than the nail’s outside diameter. We aim at a position of neutral dorsiflexion, 5° of hindfoot valgus, and external rotation approximately corresponding to that of the contralateral side (sometimes depending on the condition of the ipsilateral proximal lower leg). The talus/calcaneus should ideally be transferred slightly posteriorly. Locking screws are placed only distally. One calcaneal sagittal screw and at least 1 transverse screw (depending on the amount of resection of the talus) are then placed. Any defect in the fusion site is then filled with cancellous bone from the resected malleoli (Figs. 6 and 7). In case of rotational instability, an additional staple or K-wire is placed for stability. As a result of the removal of bone, the skin incisions can then be sutured without tension (Fig. 8). Postoperative radiographs are obtained for control of bone contact and placement of screws (Figs. 9 and 10).
A nonweight-bearing below-the-knee plaster of Paris cast is applied on the first postoperative day. Weight bearing is avoided for 3 weeks followed by partial weight bearing until radiographs show signs of union. The absence of proximally locking screws makes some compression over the arthrodesis site possible.
One case of varus deformity is shown in Figures 11–16 and a case of valgus deformity is shown in Figures 17–20.
We have used partial or total removal of the talus and fixation with retrograde nailing in a number of patients with severe hindfoot deformities. The early results are encouraging. Even patients with severe fixed deformities have been possible to treat. In those cases, some residual translatory deformity has to be accepted but could be partially disclosed by the resection of the malleoli.
The most frequent complications after tibiotalar, subtalar, and triple arthrodeses involve nonunion, malunion, infection, and wound complications. The risk of nonunion in the ankle and subtalar joints has been reported as high as 41% and 16%, respectively. 7 Several factors have been reported to significantly increase the incidence of nonunion: smoking, previous nonunion, osteonecrosis, history of infection, and major medical problems. Smokers have a significantly higher rate of nonunion than nonsmokers. The relative risk of developing a nonunion was 2.7 times higher for smokers than nonsmokers, but there was no statistical difference in the rate of infection or delayed wound healing among the groups in a study by Ishikawa et al. 6 It therefore seems reasonable to avoid this kind of surgery in smokers.
In our experience, it seems that the rate of nonunion is lower with the medullary nail technique than with internal screw fixation. Infection, although rare, is a severe complication, leading eventually to revision operations and problems with osteoporotic bone, fragile soft tissues, and skin. 2,7
Tibiotalocalcaneal arthrodesis with medullary nail fixation is a demanding but very useful technique for correction of severe hindfoot deformities in patients with rheumatoid arthritis.
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