Early outcomes of pes planus reconstruction using either hamstring allograft or synthetic ligament

L. Weigelt, G. Heyes, E. Swanton, L. Mason, A. Molloy

Introduction: The medial longitudinal arch is crucial to efficient gait and the Spring and Naviculocuneiform ligaments are important stabilisers. Attenuation of these ligaments leads to Pes Planus deformity and subsequent defunctioning of the PTT. This prospective study evaluates the functional and radiological outcomes of Spring and Naviculocuneiform ligament reconstruction using Hamstring (Semitendinosis) allograft vs. Synthetic ligament (Internal BraceTM, Arthrex).

Methods: 33 reconstructions were performed 11/11/2013-06/03/2018. All patients underwent serial radiographs and functional scores including; MOXFQ, EQF5D and VAS, within minimum six month follow up. Surgery included a proximal medial gastrocnemius recession and medialising calcaneal osteotomy where required. For allograft reconstructions, a pre-tensioned Semitendinosis allograft was fixed proximally to Talar neck using a tenodesis screw and passed plantar to PTT and through a bone tunnel in the medial cuneiform. Synthetic ligaments were inserted from the Sustentaculum Tali to the medial cuneiform in a hammock fashion. In both reconstructions tendinopathic PTTs were excised and FDL transfered. 17 were synthetic ligament reconstructions (6 male/11 female) and 16 allograft reconstructions (6 male/10 female). Groups were matched pre-operatively for age, functional scores and radiological markers (T-test P-values >0.05).

Results: At six months significantly better improvements were observed in the synthetic ligament group compared to allograft group with regards to VAS, MOXFQ pain score, Meary's line, 1st metatarsal Talus angle, Talonavicular uncoverage angle and Hindfoot alignment (T-test P< 0.05). Statistical significance was maintained at 12 months with the synthetic ligament providing a significantly better reduction of Meary's line 1st Metatarsal Talar angle, Talonavicular uncoverage and hindfoot alignment. 2 patients were revised to double fusions in the allograft group and 1 patient revised in the synthetic ligament group.

Conclusions: Statistically significant improved functional scores and radiological appearance can be found up to 1 year following Synthetic ligament reconstruction of the Spring and Naviculocuneiform ligaments when compared to Hamstring allograft.