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Abstract & Commentary
Synopsis: Although patients improved their pain and function outcome measures, there was a 24% graft failure rate. Using the ipsilateral patellar tendon a second time yielded an unacceptably high failure rate of more than 50%.
Source: Noyes FR, Barber-Westin SD. J Bone Joint Surg. 2001;83-A(8):1131-1143.
Primary ACL reconstruction with patellar tendon grafts has been shown to be successful with the graft failure rate between 3 and 10%. Noyes and Barber-Westin prospectively evaluated revision-ACL reconstructions using patellar tendon grafts and retrospectively compared this to a similar study with allografts. In this study, 57 consecutive ACL revisions were prospectively followed with only 2 knees lost to follow-up. Initial graft failure was due to improper graft placement, associated ligamentous insufficiencies or traumatic reinjuries, all about equal in their incidence. Virgin patellar tendon from either the ipsilateral or the contralateral leg was used in all but 11 knees. In these 11 knees, a graft was obtained from the same knee in which the patellar tendon was previously harvested. About two thirds of the knees had a 2-incision, arthroscopic-assisted technique in order to change the orientation of the femoral tunnel and avoid the prior interference screw or collapse of the bony bridge between the tunnels. The other third had a single-incision arthroscopic technique performed. No knees required bone grafting for unusually large tibial or femoral defects. All knees prior to surgery have positive pivot shift tests and greater than 6 mm of side-to-side difference on KT 2000 testing.
Patients were postoperatively evaluated by KT 2000 arthrometry (by the same examiner for reliability), the Cincinnati knee rating system, weight-bearing radiographs, and assessment of the ability to return to sports and occupations. About half of the knees had some other major reconstructive procedure performed in addition to the ACL revision. This included reconstruction or tightening of the posterolateral ligamentous structures in 29%, or high tibial osteotomies for varus knees in about 20%, or 1 case of MCL replacement. Osteotomies were staged and done prior to the ACL revision surgery; whereas, the ligamentous reconstruction procedures were done at the same time. The postoperative rehabilitation progressed relatively slowly with a brace and protective weight bearing until 6 weeks, and continued for 12 weeks for those patients with posterolateral reconstructions. Running was not begun until 6 months, and full return to activities was not permitted until between 9 and 12 months.
Noyes and Barber-Westin found statistically significant improvements in the scores for pain, activities of daily living, sports participation, patient satisfaction, and the overall rating of the knee at a mean of 33 months (range, 2-6 years) postoperatively. Based on positive pivot shifts and a KT 2000 greater than 6 mm of translation compared to the opposite side, 13 knees (24%) had failed grafts. The posterolateral reconstruction was successful in all but 1 patient. This was performed with an advancement of the femoral attachment of the posterolateral structures in line with the LCL before staple fixation at the original attachment site. Those patients with the simultaneous ligamentous reconstruction procedures tended to have lower scores, perhaps reflecting a greater amount of surgery and the more severely damaged knees.
COMMENT BY DAVID R. DIDUCH, MS, MD
Noyes and Barber-Westin are to be congratulated on another excellent addition to the sports medicine literature. Their follow-up is impressive and their statistics and conclusions are sound. They offer an excellent benchmark from which we can counsel patients and base decisions. Their findings demonstrate that the revision ACL knee is far more difficult than the primary ACL knee. The failure rate of 24% is only part of this picture. The majority of these knees had associated chondral and meniscal damage that was in excess of that usually encountered with primary ACL injured knees. Although the meniscal healing rates with aggressive repair using inside-out, nonabsorbable sutures was quite good, the excessive intra-articular damage tended to lower the patients’ return to sports and activities.
Additionally, this paper offers a comparison to a prior study performed by the same authors with revision ACL reconstructions using bone patellar tendon bone allografts.1 The graft failure rate in that study was 33% of 75 consecutive knees. This is certainly higher than 24% and, as such, Noyes and Barber-Westin no longer recommend using allograft patellar tendon for revisions. Unfortunately, Noyes and Barber-Westin do not evaluate hamstring autogenous grafts as an alternative. They conclude that they recommend autogenous patellar tendon grafts not taken from the same knee as before, yet they do not have any control group in this cohort type study. It would be most interesting to see if hamstring techniques with the modern fixation methods would improve upon this failure rate and also reduce the morbidity associated with the operation. An important point in this paper is that using the same patellar tendon twice is not safe. Six of the 11 knees in which this was performed subsequently failed. This has been something reported sporadically in the literature and often entertained by sports medicine surgeons but frequently abandoned out of fear. This study dissuades the use of the same tendon even years after the prior harvest.
An additional strength of this paper is the excellent description of Noyes and Barber-Westin’s decision making for reconstructing associated ligamentous deficiencies. Those knees that have a primary varus deformity of the tibia, or even double varus knee with associated deficiency of the LCL, do well with a high-tibial osteotomy, which they recommend staged prior to the ACL revision. However, the triple varus knee that has varus plus LCL laxity plus posterolateral corner laxity is appreciated to have increased lateral joint opening at 30° of flexion, a varus thrust, as well as increased external tibial rotation and hyperextension. These triple varus knees require a staged high tibial osteotomy plus a posterolateral ligament reconstruction or advancement at the time of the ACL revision surgery. A knee with a varus thrust and lateral laxity puts abnormal stress on an ACL graft as the lateral side of the knee gaps open all the way across to involve the intracondylar notch, thus stretching the graft. Noyes and Barber-Westin recommend an accessory extra-articular iliotibial band procedure for some knees that have excessive laxity of the secondary restraints but do not provide evidence in this particular paper to support its use.
1. Noyes JL, Barber-Westin SD. Am J Sports Med. 1997;25:460-471.