LONG-TERM RESULTS AFTER ACL RECONSTRUCTION USING BPT VS HAMSTRING GRAFT IN AN IMPLANT FREE PRESS-FIT TECHNIQUE: A NINE-YEAR FOLLOW-UP

Abstract

The goal of this prospective, randomized study is the long-term evaluation of clinical, functional and MRI results after implant free press-fit ACL reconstruction performed using the bone-patella-tendon (PT) vs. hamstrings (HT) graft.

62 ACL insufficient patients without any concomitant sports injuries took part in a prospective, randomized study (31 PT, 31 HT). All procedures were conducted by the senior author between 10/98 and 09/99. Both surgical procedures were performed without any implants in press-fit technique with intra-operative x-ray control. At a mean FU time of 8.8 years 53 patients (28 PT, 25 HT) were examined by different scores, KT-1000, one leg hop test, kneeling- and knee-walking-test and isokinetic examination. We also performed bilateral MRI to determine the cartilage defects of both injured and uninjured knee. The results were compared with the intra-operative cartilage status. All MRIs were examined by an independent radiologist. For statistical analysis, the Student’s t-test and the chi²–test was used (p< 0.05).

On FU, neither the Tegner nor the Lysholm Score showed any significant results (Tegner 4.86 PT/5.29 HT, Lysholm 87.2/92.47). In the IKDC Score 84% of the PT and 94.4% of the HT group had a normal or nearly normal result (A or B) (p< 0.05), none had a severely abnormal result (D). The KT-1000 stability test and the pivot shift test showed no significance (KT-1000 side-to-side difference of < 3 mm 95.1%/91.7%; pivot glide in 28.0%/17.6%, no cross pivot shift). Isokinetic testing showed nearly normal quadriceps function in both groups (96.0%/96.4%), the hamstring strength was lower in the HT group without reaching statistical significance (100.3%/95.1%). The significant difference of the kneeling- and knee-walking-tests at 1 year FU persisted at year 9 (kneeling: 1.5/1.1; knee-walking: 1.72/1.14 (p< 0.05). Also, the single leg hop test was better in the HT group; however, the results were not significant (95.8%/99.1%).

The MRI results showed no difference in cartilage status grade 0–2 using the ICRS-protocol (69.6%/65.0%), the cartilage status of the uninjured knees showed in both groups a similar distribution. Tunnel measurements did not show any widening of the femoral tunnel (−11.3%PT, −0.4%HT). However, the tibial tunnels were clearly widened in both groups (+16.0%/+15.7%). Also, the Caton Index for patellar height (−0.073/−0.085) as well as the sagittal ACL angle (+1.96°/+2.37°), both compared to the uninjured knee, revealed no significant difference.

The implant free press-fit technique of ACL reconstruction using PT and HT grafts with anatomic graft placement is an excellent technique to preserve the cartilage and meniscal status without any significant differences between the operated and non-operated knees on FU. A significantly lower morbidity was noted in the HT group.