To The Editor:
I read with great interest "Hallux Valgus and First Ray Mobility. A Prospective Study" (2007;89:1887-98), by Coughlin and Jones. I would like to congratulate the authors on a comprehensive study addressing very timely questions. However, I am a bit puzzled at the conclusions.
In the final sentences, the authors conclude that there is "little clinical evidence to substantiate…that increased mobility at the first metatarsocuneiform joint can lead to hallux valgus." However, earlier in the paper, the authors state, "We believe that the metatarsocuneiform joint is the key to the development and the progression of a hallux valgus deformity." Are not these two statements at odds with each other? The authors acknowledge the role of the metatarsocuneiform joint in the deformity, but they question the concept of joint instability.
I am aware of the debate in the recent past between various foot and ankle "schools" on osteotomy as opposed to metatarsocuneiform fusion for hallux valgus. Unfortunately, I think we are all missing the "forest from the trees." The concept of first metatarsal hypermobility or instability was introduced to suggest that first metatarsocuneiform deviation was a necessary step, and perhaps the first step, in the development of hallux valgus.
The Klaue device, which measures vertical translation of the first ray through the medial naviculocuneiform and first metatarsocuneiform joints, has not been proven, nor widely accepted, as a measure of first ray instability. Instability may be more of a concept than a physical measurement. One might argue that there must be some degree of metatarsocuneiform instability to allow the joint to deform at all.
Perhaps the Klaue device is not "asking the right questions." We need to think about the problems fundamentally.
Everyone would agree that hallux valgus arises from deformity at the first metatarsophalangeal and metatarsocuneiform joints in most or all patients. In no case does it arise from an acquired angulation in the first metatarsal bone. The most logical solution is to address the deformity by restoring normal alignment at the joints as is done with a modified Lapidus procedure. Any metatarsal osteotomy is creating a secondary deformity to compensate for the primary one.
That is not to say that every patient is best served with a modified Lapidus procedure. There are downsides, including slow recovery, technical difficulty, and nonunion. The end must justify the means, and for many patients these problems with the Lapidus procedure outweigh the advantages. For these patients, a metatarsal osteotomy may be the perfect compromise.
The authors have established that vertical translation of the first ray improves following proximal metatarsal osteotomy with temporary transarticular fixation. They have not proved that instability of the first ray is not a cause of hallux valgus. Furthermore, we still cannot determine how hallux valgus deformity begins. What is the first step? What is the necessary pathophysiology? As is the case too often in medicine, we are left with more questions than answers.
I again congratulate the authors on addressing such a controversial issue, but the concept of first metatarsal instability remains alive.