Is ACL Surgery Effective for Skeletally Immature Adolescents?

Abstract

Source: Kocher MS, Smith JT, Zoric BJ, et al. Transphyseal anterior cruciate ligament reconstruction in skeletally immature pubescent adolescents. J Bone Joint Surg Am. 2007;89(12):2632–2639; doi 10.2106/JBJS.F.01560Management of anterior cruciate ligament (ACL) injuries in skeletally immature patients is controversial. In a retrospective case series from Children’s Hospital, Boston, researchers evaluated the outcome of transphyseal reconstruction of the ACL in adolescents with a complete ACL tear. The study population consisted of 59 patients who underwent similar surgical repairs between 1996 and 2004.The procedure was an arthroscopically assisted transphyseal reconstruction of the ACL with use of an autogenous quadrupled hamstrings-tendon graft through bone tunnels that cross the femoral and tibial physes with metaphyseal fixation. Outcome measures included physical examination for limb length discrepancy, physical measures of knee laxity, and two functional outcome instruments. Angular deformity and growth arrest were evaluated by postoperative radiographs.Sixty-one ACL reconstructions were performed on 23 boys and 36 girls. The mean age of patients at the time of surgery was 14.7 years (range 11.6–16.9) and mean skeletal age was 14.4 years. All patients were Tanner stage 3.1The four most common causes of knee injury were soccer (22), football (8), skiing (6), and basketball (5). Surgery was performed at a mean of 3.8 months (range 0.5–24 months) after injury. There were 31 knees with an associated meniscus injury. Postoperative follow-up occurred at a mean of 3.6 years. None of the knees had abnormal laxity. Only two patients (3% revision rate) had a graft failure that required revision reconstructive surgery. Both of these patients had a re-injury while participating in cutting and pivoting sports and were re-operated on 14 and 21 months after their original surgery.All patients were able to return to their cutting or pivoting sport by six months after surgery. The mean increase in their total height after surgery averaged 8.2 cm (range 1.2–25.4 cm). No postoperative growth disturbances were seen on radiographs, nor were any clinical limb length discrepancies noted. There were no differences in functional outcome measures between boys and girls or between patients younger or older than 14 years. The authors conclude that transphyseal reconstruction of the ACL in skeletally immature pubescent adolescents results in an excellent functional outcome with a low revision rate and a minimal risk of growth disturbance.Dr. Schwend has disclosed no financial relationship relevant to this commentary. This commentary does not contain a discussion of an unapproved/investigative use of a commercial product/device.Adolescent athletes with an ACL-deficient knee often remain very active and risk sustaining further meniscal and articular cartilage damage unless they receive surgical stabilization before returning to their sports.2However, conventional surgical reconstruction techniques used in adults can cause iatrogenic growth disturbance due to damage to the distal femoral physis and/or the proximal tibial physis in children.3 The results of this study suggest that for a child at Tanner stage 3 development, ACL reconstruction is safe and effective. For the older adolescent (Tanner stages 4 and 5) who is approaching skeletal maturity, standard adult techniques can probably be safely utilized.The authors noted several limitations of this study, including a relatively short follow-up duration as well as collection of data on only 70% of the total eligible patients. Also, there was no comparison group treated by other methods, and the final assessment of outcome was performed by the two surgeons performing the procedures, which could introduce bias.With a mean chronologic age of 14.7 years, it is likely that most girls in this series had already achieved menarche; providing specific information on menses would have been helpful. Because separate results in boys and girls were not reported, the reader cannot determine whether variations in chronological or skeletal bone age impacted outcomes for each group. This is important because the variation in the amount of total height achieved after surgery was considerable.In a larger series some patients with remaining growth might develop a growth abnormality. On the other hand, some younger patients at Tanner stage 2 might do well with this transphyseal soft tissue technique, rather than the less anatomical technique that avoids the physis.The authors’ data support the safety of this surgical technique for the pubescent Tanner stage 3 athlete with an ACL-deficient knee. These patients should be counseled about availability of such surgical treatment and the long-term risks of returning to cutting and pivoting activities without ACL reconstruction.Because pediatricians are often the ones to see adolescents following knee injuries, we need to take our physical examination texts out of the drawer and bone up on the examination of the knee to identify ACL tears, the long-term risks of such injuries, and the surgical techniques for reconstruction so we can give teens and their parents the best possible advice.