What A New Study Reveals About Tendon Lengthening For Diabetic Plantar Foot Ulcers

Monroe Laborde, MD

   The metatarsal osteotomy for 22 ulcers plantar to metatarsal heads in 20 patients resulted in a 95 percent (21/22) healing rate. However, there was also a 91 percent (20/22) complication rate with 17 months average follow-up.22 Complications after metatarsal osteotomy included acute Charcot arthropathy in 32 percent (7/22) of the ulcers, transfer ulcers in 23 percent (5/22), wound infection in 32 percent (7/22), a below-knee amputation in 5 percent (1/22) and no recurrences. In the present study on tendon lengthening for the same problem, 98 percent (43/44) of ulcers healed with a 52 percent (23/44) incidence of complications at 38 months average follow-up. Complications included a 16 percent rate (7/43) of ulcer recurrence, a 28 percent (11/40) incidence of transfer ulcers and a 3 percent (1/40) incidence of a subsequent major amputation for gangrene. There were no wound infections and no new or acute Charcot arthropathy. Ten percent (4/40) of patients died.

   The recent thinking is that midfoot ulcers are caused by a combination of gastrocnemius-soleus tightness and a loss of protective sensation. Gastrocnemius-soleus tightness and protective sensation loss theoretically cause midfoot arthritis and/or arch collapse, which leads to midfoot plantar bony prominence and a subsequent midfoot ulcer.23,24 This theory is consistent with the lack of progression of Charcot deformity after tendon lengthening.

   Weiman and co-workers healed 60 percent (32/54) of midfoot ulcers with exostectomy but 39 percent (21/54) had an amputation.25 Early and Hansen healed 7 of 10 midfoot ulcers with fusion but noted complications in eight of these cases. Complications included two transfer ulcers, three "wound problems," two amputations and one death.26 The present study on 10 midfoot ulcers in 10 patients had an average follow-up of 31 months. Nine of 10 healed and none recurred. Two patients had amputation for gangrene and one patient died. Accordingly, there was a 30 percent complication rate in this study.

   The aforementioned studies described results of metatarsal head resection, metatarsal osteotomy, exostectomy and fusion. Tendon lengthening appears to heal more ulcers with less complications than these bony procedures.

   Ray amputation has a high 18 percent (16/89) rate of additional amputation in patients with diabetes and forefoot ulcers.27 Krause and colleagues used transmetatarsal amputation to treat chronic diabetic forefoot ulcers.28 Krause and colleagues used transmetatarsal amputation to treat chronic diabetic forefoot ulcers.28 In their study, wound breakdown occurred in 12 percent (8/65) of feet, transtibial amputation occurred in 26 percent (17/65). In addition, three of 60 patients were lost to follow up and 30 percent (17/57) died. In comparison to the complications with partial foot amputation, complication rates with tendon lengthening in the present study were lower. There was a 7 percent (5/75) incidence of amputation, no incision problems and 12 percent (9/75) died.

   The 7 percent (5/75) amputation rate in this study is less than the 16 percent (75/468) amputation rate that Apelqvist and co-workers reported in another study three years after ulcers healed after non-operative treatment.29 All amputations in this study were from gangrene due to arterial insufficiency. None of the amputations were due to ulcer infection. This amputation rate is much less than the 84 percent (67/80) amputation rate secondary to foot ulcers reported by Pecararo and colleagues.1 This is consistent with a reduced amputation rate after tendon lengthening.

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