Flexor tenotomy is a minimally invasive surgical procedure for off-loading claw and hammer toe deformities. In this retrospective study, previously reported findings that diabetic foot ulcers on the distal end of the toe heal quickly after flexor tenotomy were replicated
[6–9]. The rate of non-healing ulcers found in the population of this study is slightly higher (9%) than seen in recently published retrospective studies (0% - 2%
[6–9]). All three ulcers that did not heal were infected and penetrated to bone at the moment of flexor tenotomy. Re-ulceration was a complication found in seven patients, which is slightly higher than previous studies where this was described
[6, 8]. As with amputation, re-ulceration occurred only in toes that were infected and penetrating to bone at the moment of flexor tenotomy. With scarce information on infection available from previous studies, options to reliably compare these findings are unfortunately limited. Infected ulcers penetrating to bone are not a contra-indication for performing flexor tenotomy, as the majority of these ulcers healed and approximately half of them without complications. However, with amputation and re-ulceration only found in this group, the timing of the flexor tenotomy should be investigated in respect to performing the procedure earlier or later (before an ulcer becomes infected and penetrating to bone is possible, or when an infection is cleared and penetrating to bone is no longer possible), or if a different treatment (e.g. off-loading by means of cast or shoe adaptations) is preferred.
A complication that has been described before is shifting of the foot problem
. After successful flexor tenotomy, the next toe may develop an ulcer due to the increased pressure under that toe. The change to the structure and therefore function of the diabetic foot has implications for a shift in plantar pressures and other forces affecting the foot, sometimes resulting in a new ulcer on the next toe. Shifted flexor tenotomy is then one of the first treatment options to consider. With eight shifted flexor tenotomies found in our population, this is not a rare complication. Frequent follow-up visits are essential to timely detect these ulcers, or the abundant callus which is a pre-sign of these ulcers. A complication after flexor tenotomy that has not been described before was dorsiflexion of the metatarsophalangeal joint. This may be caused by the extensor digitorum longus muscle, without active muscle contraction, or by the inadvertent release of the flexor brevis muscle. This was found in one patient, one month after the flexor tenotomy. There was inadequate space in the toe-box of the shoe due to the altered toe position, and consequently an ulcer developed on the dorsal side of the toe. Frequent follow-up visits and timely made shoe adaptations can prevent ulceration due to this complication.
Prophylactic flexor tenotomies have only been described once, yet without describing the effectiveness of the prophylactic intervention
. In this study, prophylactic flexor tenotomy was successful in the prevention of ulcer development during long-term follow-up. This suggests that flexor tenotomy may hold promise as a measure for prevention and might be considered, if possible, in an early stage of treatment, before an ulcer can develop. It should be noted that our sample was limited to nine people only, so more research is needed before we can draw definitive conclusions.
The retrospective nature of this study presents an important limitation. Although prospective studies are preferred
, this retrospective design was chosen to investigate the relation between ulcer duration, preoperative treatment, ulcer location, or infection on healing and time to heal after flexor tenotomy. The findings, especially concerning the influence of infection and penetrating to bone at the moment of flexor tenotomy, are relevant and useful additions when setting up prospective trials. The effect of flexor tenotomy should be compared with conservative non-surgical treatment options such as off-loading by means of casting or shoe adaptations, and also compared with open surgical procedures such as resection arthroplasty and toe amputation in future research. The influence of infection on negative outcomes seen in this study cohort should be considered further to determine optimal timing for surgical procedures in the diabetic foot.