Background: Targeted muscle reinnervation (TMR) is an effective technique for the prevention and management of phantom limb pain (PLP) and residual limb pain (RLP) among amputees. The purpose of this study was to evaluate symptomatic neuroma recurrence and neuropathic pain outcomes between cohorts undergoing TMR at the time of amputation (ie, acute) versus TMR following symptomatic neuroma formation (ie, delayed). Methods: A cross-sectional, retrospective chart review was conducted using patients undergoing TMR between 2015 and 2020. Symptomatic neuroma recurrence and surgical complications were collected. A subanalysis was conducted for patients who completed Patient-Reported Outcome Measurement Information System (PROMIS) pain intensity, interference, and behavior scales and an 11-point numeric rating scale (NRS) form. Results: A total of 105 limbs from 103 patients were identified, with 73 acute TMR limbs and 32 delayed TMR limbs. Nineteen percent of the delayed TMR group had symptomatic neuromas recur in the distribution of original TMR compared with 1% of the acute TMR group (P < 0.05). Pain surveys were completed at final follow-up by 85% of patients in the acute TMR group and 69% of patients in the delayed TMR group. Of this subanalysis, acute TMR patients reported significantly lower PLP PROMIS pain interference (P < 0.05), RLP PROMIS pain intensity (P < 0.05), and RLP PROMIS pain interference (P < 0.05) scores in comparison to the delayed group. Conclusions: Patients who underwent acute TMR reported improved pain scores and a decreased rate of neuroma formation compared with TMR performed in a delayed fashion. These results highlight the promising role of TMR in the prevention of neuropathic pain and neuroma formation at the time of amputation. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, III.

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Low energy availability (LEA) is defined as a mismatch between an individual's energy intake (EI) and energy expenditure (EE) in exercise, leaving insufficient energy to support normal physiological function and maintain metabolic homeostasis. Periods of LEA are common amongst endurance athletes and may occur due to increased EE, reduced EI, or both. While chronic exposure to LEA is associated with negative health outcomes, to date the effects of acute LEA on parameters of endurance performance have not been characterized. PURPOSE: to determine if short-term LEA exposure negatively impacts factors contributing to endurance performance. METHODS: elite race walkers (n=21, 18 male, 3 female; VO 2peak 63 ± 5 mL/min/kg) underwent a 4-stage exercise economy test and competed in a 10,000 m race prior to and following 8-d of a high energy (HEA; ~ 40 kcal/kg fat free mass (FFM); n=11) or LEA (15 kcal/kg FFM, n=10) diet during a 4-week intensified training camp. DXA and resting metabolic rate were measured to calculate energy availability, while a subset of participants also had DXA measured post intervention to assess changes in body composition. RESULTS: fat oxidation rates during the economy test increased across the training camp (n=21; p<0.001), with a reciprocal decrease in carbohydrate (CHO) oxidation (p<0.001), however there were no differences between dietary treatments. The oxygen cost of exercise (relative VO 2 , mL/min/kg) decreased across all 4 stages in both groups (p<0.001), indicating an increase in exercise economy, while there was no change in VO 2max . Athletes in the LEA intervention (n=7) displayed a decrease in body mass (68.1 ± 6.4 vs. 66.6 ± 6.3 kg, p<0.05) and fat mass (9.0 ± 2.7 vs. 7.9 ± 2.6 kg, p<0.05), but maintained total FFM. Athletes in the HEA group (n=5) displayed no changes in body mass or composition. Race performance was improved in both groups (LEA; 3 ± 2%, HEA 4 ± 2%, p<0.001) with no difference between dietary treatments. CONCLUSION: long-term performance preparation involves integration of strategies to alternatively manage training support, physique management and fuel availability. Acute 8-d exposure to LEA resulted in a decrease in total body and fat mass, but reduced training quality. However, with acute replenishment of CHO availability, there was no short-term impairment in race performance.