Purpose of the study: Ligamentoplasty using an autologous transplant provides an effective and long-lasting solution for anterior instability of the knee. The most widely used transplant is the mid third of the patellar tendon. The short- and long-term stability has been proven, but there are reports of morbidity at the donor site affecting the extensor system. Different attitudes have been proposed. Certain authors leave the site open, only suturing the peritendon. Others suture the two peripheral thirds together, either directly or after combing. This different therapeutic options may modify patellar height and affect the tissue at the donor site that some authors suggest can provide transplants for repeated ligamentoplasties. The purpose of this work was to assess the influence of closing the donor site of the patellar tendon on patellar height.
Material and method: Two groups of 40 patients were compared. These patients underwent arthroscopic ligamentoplasty for anterior instability of the knee, excluding all other knee pathology. In the first group, the pretendon fibrous plane was closed alone at the end of the procedure without bringing together the edges of the tendon donor site. In the second group, the peripheral thirds of the patellar tendon were sutured together directly. Patellar height was assessed according to Caton, to Blackburn and to Insall and Salvati on lateral views (20 degrees flexion) of the knee six months after arthroscopy.
Results: Irrespective of the method used to measure patellar height, there was no statistical difference between post-operative patellar heights between the two groups (Caton=1.002 +/- 0.176/1.023 +/- 0.215; Blackburne=0.844 +/- 0.183/0.882 +/- 0.196; Insall and Salvati=1.118 +/- 0.213/1.184 +/- 0.146 for group 1 "open tendon" and group 2 "closed tendon" respectively). Pre- and post-operative heights were not different for either group (Student t - Fisher, p=0.05).
Discussion: Patellar height is not significantly changed after ligamentoplasty using the mid third of the patellar ligament with or without closing of the donor site.