Balancing Digital Arthrodesis With Flexor Tendon Transfers And MPJ Corrections
Hammertoe correction, one of the mainstays of podiatric surgery, is not as simple and straightforward as one would think. A surgeon may schedule a hammertoe surgery and assume an arthroplasty will correct the deformity. The surgeon is thinking this procedure is quick, easy to perform and he or she will be in and out of the operating room in no time.
Perhaps there is some contracture at the metatarsophalangeal joint (MPJ). The surgeon assumes it will heal well in proper alignment with a K-wire across the joint holding the digit in position with the MPJ. He or she anticipates that the soft tissue structures will heal in a fixed position, thus reducing the contracture.
We know now from many years of performing surgical procedures for hammertoe corrections that it is more involved than just a simple arthroplasty (proximal head resection).1 We understand that older techniques usually yielded unsatisfactory results over time. Now let us discuss what we should do to obtain successful hammertoe correction.
For those who have been in practice long enough, we understand that relying on just a K-wire to maintain alignment is not sufficient unless we are talking about the most mild of cases. Hammertoe surgery does not just involve joint fusions of the lesser toes but also the influential soft tissue structures surrounding the MPJ. These structures include the extensor and flexor tendons, extensor apparatus, MPJ capsule, ligament structures and the metatarsals themselves.1-3
Although proximal head resection arthroplasty may still have a place for the elderly surgical patient, we have seen over the years that digital fusions provide the greatest long-term success.
Essential Considerations With Hammertoe Surgery
The range of hammertoe deformities includes proximal interphalangeal joint (PIPJ) abnormality involving the PIPJ only, claw toe deformities involving the PIPJ and distal interphalangeal joint (DIPJ), and mallet toe deformities that involve the DIPJ.
In the majority of PIPJ fusion deformities, there is usually some mallet toe deformity that one should address. Usually, this deformity is positional and one can solve this with soft tissue corrections. Flexor tendon transfer procedures remove this deforming force at the DIPJ.
However, at times, there are structural deformities that surgeons should address. There are many types of deformities involving the digit and metatarsophalangeal joint. These include predislocation syndrome, crossover deformities with secondary ligament pathology, plantar plate instability, long second metatarsal and neurological entities such as Charcot-Marie-Tooth disease.2
The main concern for surgical correction is to maintain metatarsophalangeal joint functionality while maintaining digital purchase as opposed to an unappealing, corrected straight toe with no contact of the weightbearing surface and dorsal migration on the metatarsal head. This is a complex problem in that hammertoe surgery involves capsular structures, tendon components and bone abnormalities.
With digital surgery, one must always be aware of the problems of prolonged swelling, possible deviations, excessively straight toes, lack of ground purchase and an unusual feeling of tightness after tendon transfer.1 Understanding these issues will help reduce the chance of problems. Communication with your patient concerning these issues will make for a more aware and happier patient.