Functional outcomes of tibialis posterior tendoscopy with comparison to magnetic resonance imaging

Background: The purpose of the current study was to report functional outcomes of tendoscopy for treatment of tibialis posterior tendon pathology as well as compare its diagnostic capability with magnetic resonance imaging (MRI). Methods: Clinical records and MRI of 12 patients who underwent tendoscopy of the tibialis posterior tendon (TPT) were retrospectively reviewed. Mean follow-up was 31 months (range, 26-43 months). Preoperative MRI findings were compared with tendoscopic findings to assess the diagnostic agreement between each modality. Functional outcomes were assessed using the Foot and Ankle Outcome Score (FAOS) and Short Form-12 (SF-12) General Health Questionnaire preand postoperatively. Mean patient age was 43 years (range, 17-63 years). Mean duration of preoperative symptoms was 15.5 months (range, 3-36 months). Results: Pathologies addressed via tendoscopy included tenosynovitis, tendinosis, stenosis, tendon subluxation, and partial thickness tear (via mini-arthrotomy). Preoperative MRI findings were in agreement with tendoscopic findings in 8 of 12 cases (67%). Tendoscopy diagnosed and allowed access for treating pathology that was missed on MRI in the remaining four cases. The FAOS improved from a mean preoperative score of 58 (range, 36-78) to a mean postoperative score of 81 (range, 44-98) (P < .01). The SF-12 score improved from a mean preoperative score of 34 (range, 13-51) to a mean postoperative score of 51 (range, 21-76) (P = .01). Conclusions: Although MRI is considered an effective imaging technique for tendon pathology, tendoscopy may be a more sensitive diagnostic tool. Tendoscopy was an effective minimally invasive tool to diagnose and treat tibialis posterior tendon pathology resulting in functional improvements in the short-term for early stage TPT dysfunction. Further studies comparing tendoscopy with traditional open approaches are warranted. Level of Evidence: Level IV, case series.