Serial magnetic resonance imaging of the donor site after harvesting the central third of the patellar tendon A prospective study of 37 patients after arthroscopic anterior cruciate ligament reconstruction

Abstract

The aim of this prospective study was to follow the development of repair tissue in the donor-site area using serial magnetic resonance imaging (MRI) evaluation and to assess whether the MRI findings were correlated with donor-site morbidity. Thirty-seven consecutive patients with unilateral anterior cruciate ligament injuries undergoing elective reconstruction of the ligament were included in the study. They were aged 27 (range 14–50) years. The graft was harvested through two 25-mm vertical incisions with the aim of protecting the infrapatellar nerve and sparing the paratenon. The tendon defect was left open. The patients underwent MRI evaluation at 6 weeks, 6 months and 27 months postoperatively. A final clinical follow-up was made 25 (range 23–29) months postoperatively. MRI demonstrated that the donor-site gap, i.e. the area corresponding to a pathological non-tendinous-like tissue signal, was 9 (range 4–18) mm at 6 weeks, 5 (range 2–14) mm at 6 months and 2 (range 0–5) mm at 27 months. The size of the donor-site gap had significantly decreased at 6 months compared with 6 weeks (P = 0.0001), as well as at 27 months compared with 6 months (P = 0.0001). We conclude that the patellar tendon at the donor site healed gradually, as expressed by a decrease in the area of non-tendinous-like tissue signal on the serial MRI evaluations.