Secrets To Managing Complications Of First MPJ Fusion

By William Fishco, DPM

Arthrodesis of the great toe joint has been described for the repair of just about every problem affecting the great toe joint, including hallux valgus, hallux varus, hallux limitus/rigidus, osteoarthritis, rheumatoid arthritis and salvage of failed surgeries of the first ray. Many foot surgeons view the great toe joint fusion as a salvage procedure and will not consider it for primary repair of hallux valgus or hallux rigidus. One of the reasons for doing any type of fusion surgery is to stabilize an unstable or hypermobile joint. With that said, the great toe joint fusion can be beneficial for the patient who has a bunion deformity and a very large intermetatarsal angle. After appropriate soft tissue release, realigning the great toe joint will reduce the buckling forces that were previously encouraging the deformity. After adequate reduction, recurrence of the deformity is uncommon following a fusion. Certainly, no one would advocate a great toe joint fusion for all bunion deformities. However, in certain cases of severe deformity and instability, it works and does make sense. When it comes to surgical treatment of hallux rigidus, there are usually two groups of surgeons: the “Keller/implant” group and the “fusion” group. I personally do not recommend doing arthroplasties of the great toe joint in active individuals regardless of their age. The reason is simple. First ray destabilization is inherent to the arthroplasty procedure. When one considers that many of the forefoot pathologies are a direct result of a dysfunctional first ray, it seems counterintuitive to create such an environment that could ultimately cause new problems. Common complications following great toe joint arthroplasties include but are not limited to lesser metatarsal overload, which can lead to stress fractures and submetatarsal pain (bursitis/capsulitis), and a non-purchasing hallux, which can lead to hammering of the hallux. Moreover, if an implant arthroplasty fails and one needs to pursue reconstruction, it becomes challenging to restore the length of the first ray. This will usually involve using a bone graft with a fusion or callus distraction with a fusion. Therefore, I tend to reserve the arthroplasty for geriatric patients with apropulsive gaits and low functional demands. In my practice, active patients who have hallux rigidus are more likely to get a fusion than anything else. Why would one intentionally try to create 60 degrees of motion in a patient who has been functioning with 10 degrees of motion? It just does not make sense to me. Minimal motion converted to no motion seems more logical. How Emphasizing Key Principles Can Minimize Fusion Complications So why do many foot surgeons shy away from the first metatarsophalangeal joint (MPJ) fusion? It most likely has to do with a long list of potential complications such as delayed union, non-union, mal-union and fixation failure, as well as prolonged immobilization with the potential for cast disease requiring extensive rehabilitation and risk of deep venous thrombosis. However, if one follows sound surgical principles, it can minimize complications of the great toe joint fusion. The great toe joint fusion is no different than any other fusion of the foot or ankle. The three most important things to remember are location, location, location. An improperly positioned fusion is going to be trouble for the DPM and the patient. If the toe is too dorsiflexed, then the shoes will irritate it and a hallux malleus is likely to develop. If the toe is too plantarflexed, then it will cause pain at the plantar interphalangeal joint and will interfere with normal biomechanics of the foot. In the transverse plane, an improperly positioned toe can either cause irritation to the second toe (abducted) or be in constant contact with the shoe (adduction). Surgeons can minimize other complications via meticulous surgical dissection, proper application of internal fixation and appropriate postoperative management. Adequate joint preparation is critical in any fusion. If one leaves cartilage or soft tissue debris in the fusion site, then it will certainly cause delay or failure to unite. There are two basic methods of joint preparation. One may opt for saw resection of the joint to obtain raw cancellous bone or utilize a curettage technique to remove cartilage and expose the subchondral bone.



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