Early Outcomes of Pes Planus Reconstruction Using Either Hamstring Allograft or Synthetic Ligament

Abstract

Category:Hindfoot, Midfoot/ForefootIntroduction/Purpose:Maintenance of the medial longitudinal arch is crucial to efficient kinematics in gait. It is supported by as complex interplay of osseous structures, ligaments, extrinsic tendons and plantar fascia.Two ligaments critical to stabilising the medial longitudinal arch are the Spring (Calcaneofibular) and Naviculocuneiform ligaments. The Spring Ligament serves as a sling within the “Acetabulum Pedis” to orientate the Talus relative to the Calcaneus and Navicular. The Naviculocuneiform ligament is an important plantar tension band and a separate entity to the Posterior Tibial Tendon (PTT) insertion. Attenuation of these ligaments leads to Pes Planus deformity and subsequent defunctioning of the PTT. This study evaluates the functional and radiological outcomes of Spring and Naviculocuneiform ligament reconstruction using Hamstring (Semitendinosis) Allograft and Synthetic ligament (Internal BraceTM, Arthrex).Methods:33 consecutive Pes Planus reconstructions were performed between 11/11/2013 and 06/03/2018. All patients were followed up prospectively with serial radiographs and functional scores including; MOXFQ, EQF5D and VAS. Minimum follow up was six months.At the midpoint during the study there was transition to using Synthetic Ligament instead of allograft. This was due to availability and ease of use.Surgical technique for both reconstructions included a proximal medial gastrocnemius recession and medialising calcaneal osteotomy. 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 a Flexor Digitorum Longus transfer used.Results:There were 17 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).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.Conclusion: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.