Proximal versus Distal Transmetatarsal Amputation: Does Length Predict Success?

Background: Trans-metatarsal amputation (TMA) is an effective surgical approach to treat forefoot infection in diabetic patients.  

Purpose: The aim of this study is to compare whether length can predict success in proximal versus distal level of amputation.  Single center.  

Methods: Retrospective analysis with 28 patients with 33 limbs who underwent TMA from Redcap database of 36 patients with 41 limbs from 05/2005 to 07/2017. Exclusion criterias are patients who underwent below or above knee amputation, lost to follow up and deceased, we excluded 8/36 patients. Age range of 24-84, 21 male, 7 female.  Average age 62.42. Average BMI 28.48 and 25/28 patients have diabetes. 13/28 pts with kidney disease, 12/28 pts with peripheral arterial disease, 9/28 pts with coronary artery disease, 9/28 were current smokers. 26/28 underwent amputation due to infection or ischemia or both, 2/28 underwent amputation due to vasopressor induced gangrene. 17 proximal level TMAs, 16 distal level TMAs. 5 patients with bilateral TMAs from these two groups. 9/28 patients underwent percutaneous or open intervention. Compared radiographs, proximal amputations were defined as less than 50% of original second metatarsal length, distal amputations were greater than 50%.  

Results: For our 28 patients with 33 limbs, 21/33 (63.63%) limbs healed, 12/33 (36.36%) limbs did not heal and subsequently required proximal amputations. 11/17 (64.70%) of the proximal level TMAs healed and 10/16 (62.5%) of the distal level TMAs healed. 9/33 (27.27%) limbs underwent percutaneous or open vascular intervention. Of this group, 4/9 (44.44%) belong to proximal TMA level amputations level compared 5/9 (55.56%) of distal TMA level amputations. Our analysis shows that 10/17 limbs (58.82%) with proximal level TMAs healed completely without revision versus 8/16 limbs (50%) distal level TMAs healed.  

Conclusion: We conclude length does not predict success.  Limitations of this study includes small sample size, surgical experience, single center, and retrospective level of evidence.