JBJS -- Letters to the Editor for Mueller et al., 85 (8) 1436-1445

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Letters to the Editor to:

Scientific Articles:
Michael J. Mueller, David R Sinacore, Mary Kent Hastings, Michael J. Strube, and Jeffrey E Johnson
Effect of Achilles Tendon Lengthening on Neuropathic Plantar Ulcers*: A Randomized Clinical Trial
J Bone Joint Surg Am 2003; 85: 1436-1445 [Abstract] [Full text] [PDF]

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Electronic letters published:

Dr. Mueller responds to Dr. Kaspar: Michael J. Mueller, David R. Sinacore, Mary K. Hastings, Michael J Strube, Jeffrey E. Johnson (28 August 2003)

Achilles lengthening for preventing recurrence of plantar ulcers: A bit of a stretch?: Sarkis (Sam) Kaspar (25 August 2003)

Dr. Mueller responds to Dr. Kaspar 28 August 2003

Michael J. Mueller,
Associate Professor
Washington University School of Medicine,
David R. Sinacore, Mary K. Hastings, Michael J Strube, Jeffrey E. Johnson
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Re: Dr. Mueller responds to Dr. Kaspar

muellermi{at}msnotes.wustl.edu Michael J. Mueller, et al.

In response to Dr. Kaspar's questions, the first pertains to the difference in weight-bearing instructions after the respective treatments. Those in the total contact casting (TCC) group were allowed to weight-bear immediately while those in the Achilles tendon lengthening (ATL) group were instructed to remain partial weight bearing for one week. Although not clearly described in the Methods section, both groups were advised to limit activities as much as possible. We agree that this difference in weight-bearing instruction is a potential, but in our view probably minimal, confounding variable to the interpretation of the results.
A greater confounding variable is the use of a walking boot by the ATL group as they transitioned from a cast to shoes. This boot was needed because of the instability that some subjects showed during walking, and this variable was discussed in the paper.
The second question relates to the actual risk of the procedure. We agree that one could consider the appearance of heel ulcers as either a recurrence or as a complication. Prior to the start of the study, we defined ulcer recurrence as being limited to the forefoot.We did not change this definition when heel ulcers developed.
The risk of infection is always a potential complication with a surgical procedure, although we have experienced only one infection in what is now a series of several hundred ATL procedures.
We do not believe there was a meaningful difference in primary wound healing. It was excellent in both groups. We believe the results of the study suggest that an ATL should be considered as an adjunct to treatment with a total contact cast in patients with a recurrent neuropathic forefoot ulcer and limited ankle dorsiflexion to reduce the rate of ulcer recurrence. The serious risk of ulcer recurrence is wound infection and lower extremity amputation.
We encourage readers to consider all benefits and risks to this procedure and discuss them with each prospective patient. Additional research is needed to help determine optimal methods to prevent ulcer recurrence without the risks of a surgical procedure.

Achilles lengthening for preventing recurrence of plantar ulcers: A bit of a stretch? 25 August 2003

Sarkis (Sam) Kaspar,
Clinical Fellow, Orthopaedic Surgery
Johns Hopkins
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Re: Achilles lengthening for preventing recurrence of plantar ulcers: A bit of a stretch?

mightysamster1{at}aol.com Sarkis (Sam) Kaspar

The article by Mueller et al on achilles lengthening to help forefoot ulcers to heal reports that even though the surgical group had non-statistically-significant trends towards longer healing times (57.5 surgical vs 40.8 days non-surgical) a larger number of ulcers healed in the surgical group (33 of 33 surgical vs 29 of 33 non-surgical),and the recurrence rate was lower in the surgical group (4 of 27 recurred vs 16 of 27 in the non-surgical group.
My first question pertains to the role of protected weight-bearing post operatively. In the Methods section, the authors state that the casting group was allowed to take full weight immediately, whereas the surgical group was protected for a week then gradually allowed to bear weight but advised to limit their activity. Doesn't this introduce a confounding variable because of the different treatment of the two groups?
Secondly, the study�s entire pool of neuropathic-foot-ulcer patients would clearly be at risk for wound complications about the ankle, a not-insignificant risk even in healthy patients undergoing achilles tendon repair. While the tenotomy style procedure likely limited this, there was one deep infection requiring surgical d�bridement, plus 4 cases of heel ulcers developing only in the surgical group, suggesting that the benefits may be more modest than proposed (for example, the heel ulcers should be counted as �plantar ulcers� and not excluded as separate complications). Hence, rather than a risk ratio of 59% to 15% (3.9, with reported 95% CI of 1.8 to 8.9 for �forefoot ulcers�), the true ratio is likely 59% versus 33% (9/27 rather than the 4/27 reported). Also, if the surgical patient who died during treatment was to be considered a peri- operative mortality, then the risk to benefit ratio is again higher.
While this is a very interesting and extensive piece of research, the full set of data in the article does lead one to become concerned over wound healing, the paper�s inclusion of heel ulcers, deep infection, and peri-operative mortality as issues separate from the recurrence rate (in the complication section for the surgical group), and the differences in weight-bearing status allowed in the two groups.
I would be grateful to the authors for their response to these comments.