Paper 197: Long-term Results After ACL Reconstruction Using Hamstring vs. BPT Graft in an Implant Free Pressfit Technique: An 8 Year Follow-up

Abstract

The goal of this prospective, randomized study is the long-term evaluation of functional and radiological 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. In the PT group 31 patients (18 male, 13 female) underwent ACL reconstruction using BPT graft. The HT group included 31 patients (15 male, 16 female) who underwent ACL reconstruction using a quadrupled hamstrings graft (semitendinosus and gracilis tendon). The time from injury to surgery was 1.51 years in group PT and 1.49 in group HT (NS). All patients were operated between 10′98 and 09′99 by the senior author. The average age in the group PT was 29.9 years (range 16-46 years) and 34.2 years (range 16-55) in group HT at the time of the operation. Both surgical procedures were performed without any implants in a press-fit technique. The same rehabilitation protocol was applied to both patient groups (accelerated rehabilitation, early weight bearing). At a mean follow-up time of 8.48 years (101.7 months) we examined 49 patients, 23 (14 male, 9 female) in group PT and 26 (14 male, 12 female) in group HT. All patients were examined 1 day pre-op, 3, 6, and 12 months and 8 years post-op with Tegner, Lysholm and the IKDC, KT-1000, one leg hop test, kneeling and knee walking test and isokinetic testing. We also performed bilateral MRI to determine the cartilage defects of both injured and uninjured knee according to the ICRS protocol and compared this with the pre-operative status. For statistical analysis we used the Student's t-test. The level of significance was p<0.05. At a mean of 8.48 years after surgery we found 6 ruptured grafts (12.2%), 3 in each group. 4 of this ruptures, 2 in the PT (8.6%) and 2 in the HT group (7.7%), were connected with new sport injuries. These patients were excluded for final examination. The Tegner Score of the other 43 patients was 4.86 in group PT vs. 5.29 in group HT (NS) compared to the pre-operative results of 4.0 vs. 4.1 (NS). The Lysholm Score was 87.2 vs. 92.47 (NS/p=0.32) compared to pre-op values of 65.4 vs. 65.7 (NS). 16 patients in the patellar tendon group and 23 patients in the hamstring group had normal or nearly normal scores in the IKDC Score (A or B) throughout the review (69.23%/88.89%). The KT-1000 stability test showed a side-to-side difference of <3mm in 92.86% of the PT group and in 88.24% of the HT group (NS). A pivot shift glide had 28.6% of the cases in group PT and 17.6% in group HT. There was no gross pivot shift in either group. Concerning ROM, there were no significant side-to-side difference in flexion deficit (2.5°/1.6°) and extension deficit (0.7°/0.5°). Isokinetic testing showed nearly normal quadriceps function in both groups (91.2%/92.4%). However, there was a significant lower hamstrings strength in the HT group (99.0%/91.4%; p=0.029), unchanged since the 12 months follow-up. The significant difference of kneeling and knee walking test between both groups at the 12 months FU persisted at the 8 year follow-up. Kneeling: 1.36/1.06 (p=0.038); knee walking: 1.64/1.06 (p=0.028). The single leg hop test was significantly better in group HT (97.0%) than in group PT (92.4%; p<0.05). MRI measurements of tunnel size did not show any tunnel widening of the femoral tunnel 8 years post-op (2.11%/0.4%). However, the tibial tunnels were significantly widened in both groups (+25.38% in group PT and +20.5% in group HT). Concerning the cartilage status, 61.6% in the PT group and 88.3% in the HT group had normal or nearly normal MRI results (p<0.05). The Caton Index for patellar height in the PT group was +0.002 compared with the uninjured knee and −0.011 in the HT group (NS). The implant free press-fit technique of ACL reconstruction using PT and HT graft is an excellent procedure to restore stability and function of the knee. Using hamstring as graft, a significant lower morbidity was noted except for a persistent hamstring deficit.