Current Concepts With Revisional Bunion Surgery
- Volume 27 - Issue 2 - February 2014
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Another patient had longstanding severe hallux varus due to an overcorrected intermetatarsal angle combined with a fibular sesamoidectomy (see above right photo). The MPJ and hallux interphalangeal joint demonstrated rigid contractures. The revision surgery involved a MPJ and hallux interphalangeal joint fusion, extensor lengthening and Z-plasty of the skin. Some shortening of the hallux was necessary due to the longstanding contractures. The result was a straight big toe that fit in a shoe and a stable platform for weightbearing.
Treating An Excessively Short Big Toe (Loss Of Big Toe Purchase)
It is not uncommon to have some shortening of the big toe after bunion surgery. However, some bunion procedures may result in more shortening than others. Excessive shortening can come from osteotomies and midfoot fusion procedures. Distal osteotomies can shorten through metaphyseal bone loss if one impacts the bone during translation of the capital fragment during the index operation. Sometimes troughing of the bone can lead to shortening. A midfoot fusion may shorten the first ray by about 0.5 cm although one can compensate for this by plantarflexing/translating the segment inferiorly. Over-resection and/or excessive wedging of the first metatarsocuneiform joint surfaces during a Lapidus bunionectomy can lead to excessive shortening.
A short segment may be short in comparison with the lesser metatarsal parabola or retracted within the first metatarsophalangeal joint, resulting in a joint contracture or loss of purchase of the big toe. The body will tolerate some degree of shortening and a short segment is only problematic (or pathologic) when the shortening results in pain or secondary structural problems. These include significant symptomatic loss of hallux purchase, prominent sub-first metatarsal head with pain and/or less metatarsalgia with pain and/or stress fractures.
One can treat this via distraction (Lapidus) with big toe joint capsular release. When the first metatarsal has been excessively shortened (and the big toe joint is intact), my treatment of choice typically involves adding length through a bone block distraction midfoot fusion. Surgeons may use various grafting materials. The lateral wall of the calcaneus is an excellent source for bicortical graft and depending on the patient, one can harvest grafts up to 2 cm. Of course, the surgeon can also perform various orientation osteotomies alternatively.
One patient had a failed bunion surgery (Lapidus bunionectomy), resulting in a very short first metatarsal and a big toe that could not purchase the ground as it was fixed in 45 degrees of dorsiflexion (see left photo). The revision involved bringing the first ray back out to length with a distraction Lapidus, using autogenous calcaneal bicortical bone block, in addition to a capsulotomy of the first MPJ (with temporary pinning). The revision bunion surgery was successful as the length of the first ray returned and the hallux could touch the ground and was functional.
Keys To Remediating Nonunions
Any bone cutting bunionectomy or bone fusion bunionectomy is at risk for incomplete bone healing (nonunion). One should not really consider a nonunion to be a complication. Rather, it is a known possible occurrence. Every joint fusion has a risk rate for nonunion. Studies estimate the rate of nonunion for the first tarsometatarsal joint at 0-10 percent.5,6 There are risk factors for developing nonunion and a common one is smoking. Surgeons should weigh these risks when considering bone surgery in general.