Factors affecting donor-site morbidity after anterior cruciate ligament reconstruction using bone-patellar tendon-bone autografts

The objective of this study was to assess knee function after anterior cruciate ligament reconstruction focusing on residual donor-site problems. Ninety consecutive patients with chronic unilateral anterior cruciate ligament rupture were operated on by the same surgeon using patellar tendon autografts, the all-inside arthroscopic technique, and interference screw fixation. At the follow-up examination 24 (range 22-32) months after the index operation, the median total anterior-posterior KT-1000 side-to-side difference was 2.5 (-7 to 11) mm. The median Lysholm score was 86 (range 37-100) points and the median Tegner activity level was 6 (range 1-9). Using the IKDC evaluation system, 62 of 90 (69%) were classified as normal or nearly normal. The median one-leg-hop quotient was 93 (range 0-167)% of the uninjured leg. Of 90 patients, 44 (49%) had minor or no discomfort when asked to walk on their knees (kneewalkers) and 46 of 90 (51%) patients had severe problems or found it impossible to perform the test (non-kneewalkers). The 'kneewalkers' had a median loss of anterior knee sensitivity of 10 (range 0-120) cm2. The corresponding value for the 'non-kneewalkers' was 25 (range 0-200) cm2 (P = 0.0001). Palpatory donor-site tenderness was registered in 19 of 44 (43%) of the 'kneewalkers' and 37 of 46 (80%) of the 'non-kneewalkers' (P < 0.001). Full hyperextension was not regained by 9 of 44 (20%) of the 'kneewalkers' and 19 of 46 (41%) of the 'non-kneewalkers' (P < 0.05). Additional surgery during the follow-up period was required by 6 of 44 (14%) of the 'kneewalkers' and 19 of 46 (41%) of the 'non-kneewalkers' (P < 0.01). Magnetic resonance imaging focusing on the donor site was performed on 31 randomly selected patients and revealed no difference between the 'kneewalkers' and the 'non-kneewalkers' in terms of patellar tendon width, thickness, length, and residual donor-site gap size. The kneewalking test was found to be a functional and reliable test for detecting donor-site morbidity. It appears that donor-site morbidity was related to problems requiring additional surgery during the follow-up period, such as extension deficit and pain near the metal implant on the tibial side, as well as the loss of anterior knee sensitivity. It appears to be important to attempt to preserve the sensitivity in the operated area during surgery and to regain full hyperextension in the postoperative period to minimize donor-site morbidity.