Donor site morbidity after anterior cruciate ligament reconstruction. Clinical, anatomical, radiographic and histological investigations with special reference to the use of central-third patellar tendon autografts

Abstract

The aim of this study was to analyse factors affecting donor site morbidity after arthroscopic anterior cruciate ligament reconstruction using autografts from the central-third of the patellar tendon. A follow-up study was performed two to five years after the anterior cruciate ligament reconstruction on 604 patients. Patients with full range of motion and preserved sensitivity in the anterior region of the reconstructed knee had significantly less anterior knee pain and fewer problems kneeling and knee-walking than patients with loss of motion and/or sensitivity. A dissection study of 60 cadaver or amputated lower extremities revealed that it was possible to harvest consistent bone-patellar tendon-bone autografts through two vertical 25 mm incisions, leaving the infrapatellar nerve(s) undamaged and the paratenon partially intact in the majority of the specimens. Thirty-five patients, in whom the patellar tendon was harvested using the traditional one-incision technique, and 37 patients, in whom the patellar tendon was harvested using the subcutaneous two-incision technique, were compared. Assessments two years after the index operation revealed that the subcutaneous technique produced less disturbance in anterior knee sensitivity and a smaller donor site gap, i.e. the area corresponding to non-tendinous-like tissue signal, as seen with magnetic resonance imaging. Serial magnetic resonance imagings performed on 37 patients, six weeks, six months and 27 months after harvesting the central-third of the patellar tendon using the subcutaneous technique revealed that the donor site gap decreased with time. Furthermore, it was shown that the thickness and width of the patellar tendon at the donor site increased compared with the contralateral patellar tendon, regardless of the time that had elapsed since the harvesting procedure. Ultrasonography-guided biopsies were obtained from the donor site area in 19 patients. Histological evaluation revealed tendon-like tissue in the central and the peripheral part of the patellar tendon, 27 months after harvesting its central-third. The repair tissue in the central part showed increased cellularity and vascularity, as compared with both the peripheral part of the harvested patellar tendon and control tissue from normal tendons. Increased cellularity and vascularity were also found in the peripheral part as compared with normal control tissue. Glycosaminoglycans and collagen type III were undetectable in the biopsies from the donor site patellar tendon. In conclusion, disturbance in full range of motion and disturbance in anterior knee sensitivity after anterior cruciate ligament reconstruction using central-third patellar tendon autografts was correlated with subjective anterior knee pain and discomfort during kneeling and knee-walking. The subcutaneous two-incision graft harvesting technique produced less disturbance in anterior knee sensitivity and smaller persisting donor site gaps than the traditional one-incision technique. The donor site gap was gradually filled with tendinous-like repair tissue, as seen on the serial magnetic resonance imagings and this was confirmed by histological evaluations 27 months after the harvesting procedure. However, the tissue in the central and the peripheral parts of the patellar tendon at the donor site displayed a significant increase in cellularity and vascularity, as compared with control tissue from normal tendons.