Extracorporeal Shockwave Therapy for Patients with Chronic Achilles Tendinopathy in Long or Short Course

METHODS: The data of 66 patients with CAT received ESWT was reviewed. According to the disease courses, those cases were allocated to short-term group (ST group, symptom duration 3-6 months) and long-term group (LT group, symptom duration >6 months). Propensity scores match (PSM) method was conducted to eliminate the confound factors in baseline features including gender, sport history, sides, type of CAT, BMI (body mass index), age, and scores evaluated by AOFAS (American Orthopedic Foot and Ankle Society) and VAS (Visual Analogue Scale) before ESWT. After balancing the features between ST and LT group, postinterventional VAS, AOFAS, and rate of Likert satisfaction scale at the 3rd month after first ESWT was statistically analyzed. RESULTS: Among the baseline features in ST and LT group, gender (female ratio, 44.4% vs 71.4%, p = 0.041) and BMI (23.26 ± 2.15 vs 24.63 ± 2.41, p = 0.024) were identified as confound factors. After elimination of biased features with PSM, 3 months after first ESWT, AOFAS and VAS in both groups are significantly improved, when compared with their scores at baseline (p < 0.01). Moreover, at postintervention month 3 (PIM3), AOFAS in ST group is significantly higher than LT group (85.08 ± 9.83 vs 76.76 ± 9.85, t = 76.76 ± 9.85, p = 0.019), and the rate of Likert satisfaction in ST group is better than LT group; although, it did not reach but close to significant level (70.6% vs 47.1%, χ(2) = 1.943, p = 0.163). However, there is no statistical difference of VAS scores between two groups after ESWT (1.96 ± 0.98 vs 2.24 ± 1.29, t = 0.703, p = 0.487). CONCLUSIONS: ESWT could effectively relieve pain and improve function of hind foot in patients with chronic Achilles tendinopathy, and especially, it could offer better benefit on functional improvement in patients with short duration of CAT symptom.