Histological evaluation of medial patellofemoral ligament reconstructed using the Leeds–Keio ligament prosthesis

Abstract

In a total of 15 knees from 15 patients undergoing medial patellofemoral ligament reconstruction using an artificial substitute and a medial retinaculum slip coverage for recurrent patellar dislocation, the reconstructed ligaments were histologically evaluated using hematoxilin-eosin and elastic van Gieson stains. The artificial substitute was a mesh-type Leeds–Keio ligament. The mean age of the patients at the time of surgery was 20 years (range; 13–38 years). The mean interval from initial reconstruction to gathering was 53 months (range; 11–109 months). In the tissue over the artificial ligament, longitudinally aligned collagen fiber bundles with spindle-shaped nuclei were formed in all specimens except one specimen of 11 months postsurgery, but it seemed to be mature ligament only in specimens more than 60 months postsurgery. The tissue inside the artificial ligament was immature as a whole in all specimens, although 13 out of the 15 specimens had regularly aligned collagen fiber bundles slightly or in some portions.

Introduction

Various materials, including patellar tendon, hamstring, iliotibial band, allograft, synthetics, menisci, and a combination of these materials, have been used for anterior cruciate ligament (ACL) reconstruction. There have been many studies on the histology of reconstructed ACL using autografts or allografts, and good revasucularization or ligamentization have been shown in both animals and humans [1], [2], [3], [4], [5], [6], [7], [8]. We have performed a medial patellofemoral ligament (MPFL) reconstruction using the Leeds–Keio (LK) ligament prosthesis and a medial retinaculum slip coverage for recurrent patellar dislocation [9]. A variety of artificial ligaments were developed and used mainly in the 1980s for ACL reconstruction surgery as alternatives to biological materials [10]. The LK polyester ligament had been developed as one of scaffold-type of prosthesis for ACL reconstruction [11], [12]. Although some early investigators [12], [13] reported good clinical results of ACL reconstruction using the LK ligament, many others have described poor results in the mid-term or long-term follow-up [14], [15], [16], [17], [18]. Recently, Murray et al. [18] reported 10 to 16 years long-term results of ACL substitution using the LK ligament. Twenty-eight percent were known to have ruptured their LK ligament and 56% had increased laxity compared with their opposite knee. However, the mid-term outcome of MPFL reconstruction using the tape-type LK ligament was encouraging [9]. It is of greater significance to assess the histological findings of the reconstructed ligament in addition to the clinical results. There have been only a few reports on the histology of reconstructed ligaments on the extra-articular portion [19] and no reports of the reconstructed ligament histologically evaluated over a long -term period of 1–9 years post transplantation even in autograft or allograft transplantation to our knowledge.

The purpose of this study was to investigate the histological findings of the reconstructed MPFL using a tape-type LK ligament for patellar dislocation.