Young athletes return too early to knee-strenuous sport, without acceptable knee function after anterior cruciate ligament reconstruction

Knee Surg Sports Traumatol Arthrosc DOI 10.1007/s00167-017-4747-8 KNEE Young athletes return too early to knee-strenuous sport, without acceptable knee function after anterior cruciate ligament reconstruction Susanne Beischer1,2 · Eric Hamrin Senorski1,2 · Christoffer Thomeé2 · Kristian Samuelsson3,4 · Roland Thomeé1,2 Received: 17 June 2017 / Accepted: 4 October 2017 © The Author(s) 2017. This article is an open access publication Abstract Purpose The purpose of this study was to evaluate the return to knee-strenuous sport rate, muscle function and subjective knee function among adolescent patients (15– 20 years of age) and adult patients (21–30 years of age) 8 and 12 months, respectively, after anterior cruciate ligament (ACL) reconstruction. It was hypothesised that no differences in outcome would be found between age groups at 8 or 12 months after ACL reconstruction. Methods Cross-sectional data from five tests of muscle function, from the Knee injury and Osteoarthritis Outcome Score (KOOS) and the Tegner Activity Scale (Tegner), performed at 8 and 12 months after a primary ACL reconstruction, were extracted from a rehabilitation outcome register. A total of 270 (51% women) athletes, aged 15–30 years, who were all involved in knee-strenuous sport prior the injury, were included at 8 months after ACL reconstruction. At 12 months 203 (51% women) were included. The return to knee-strenuous-sport rates and the rate of achieving a limb symmetry index of ≥ 90% in all five tests of muscle function, defined as recovery of muscle function, and subjective * Susanne Beischer 1 Unit of Physiotherapy, Department of Health and Rehabilitation, Institute of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, Box 455, 405 30 Gothenburg, Sweden 2 Sportrehab Sports Medicine Clinic, Stampgatan 14, 411 01 Gothenburg, Sweden 3 Department of Orthopaedics, Sahlgrenska University Hospital, Mölndal, Sweden 4 Department of Orthopaedics, Institute of Clinical Sciences, The Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden knee function scores, as measured with the KOOS, were compared between age groups. Results The adolescent patients had a higher (50%) return to knee-strenuous sport rate compared with the adult patients (38%) 8 months after ACL reconstruction (p = 0.04). At the 12-month follow-up, no difference was found between the age groups; 74 and 63%, respectively. At the 8-month follow-up, 29% of the patients, in both age groups, who had returned to sport had recovered their muscle function in all five tests of muscle function. At the 12-month follow-up, the corresponding results were 20% for the adolescents and 28% for the adult patients. No difference in mean KOOS scores was found between the age groups at 8 or at 12 months after ACL reconstruction. Conclusion The majority of young athletes make an early return to knee-strenuous sport after a primary ACL reconstruction, without recovering their muscle function. To set realistic expectations, clinicians are recommended to ensure that young athletes receive information about not to return before muscle function is recovered and that this may take longer time than 12 months. Level of evidence II. Keywords Adolescents · Knee · Rehabilitation · Muscle function · Return to sport · Register study Introduction One of the most devastating consequences when returning to sport (RTS) after anterior cruciate ligament (ACL) reconstruction is a subsequent ACL injury. Adolescent patients (15–20 years) run a remarkably increased risk of a second ACL injury; up to 30% will require a new ACL reconstruction within the first two years after RTS [1, 2, 13, 23, 27, 13 Vol.:(0123456789) Knee Surg Sports Traumatol Arthrosc 34, 36]. Two identified risk factors for an additional ACL reconstruction are primary ACL reconstruction at younger age, i.e., age < 20 years [9, 19, 20, 28], and higher activity level [2, 9, 19, 28, 36]. Recent studies have highlighted and discussed the importance of delaying RTS to at least 9 months to lower the risk of a subsequent ACL injury [14, 23]. Further, restoring muscle function before RTS is regarded as another important factor [14, 21] in lowering the re-injury risk. The limb symmetry index (LSI) is the most frequently reported criterion for assessing whether strength and hop performance is classified as normal or abnormal. An LSI of > 90% is commonly regarded as sufficient for both leg muscle strength and hop performance after ACL injury and reconstruction [4, 22, 31]. However, several studies report that many patients do not achieve this level in a combined battery of strength and hop tests 6–12 months after ACL reconstruction [11, 14, 17, 32, 35]. Younger age appears to favour returning to the pre-injury level of sport [3]. However, it has not previously been reported whether younger athletes (15–20 years old) recover their muscle function before they return to kneestrenuous sport. Patients have been reported to have high expectations on the overall condition of the knee joint 12 months after an ACL reconstruction, especially younger patients, patients without previous knee surgery, and highly active patients [10]. Furthermore, patients who return to sport have been found to have less impairment during sport and recreation and enhanced knee-related quality of life after ACL reconstruction as compared to patients who do not return to sport [8, 16]. However, it is not known whether there is any discrepancy in subjective knee function between patients of different ages who return to sporting activities. Taken together, patients under the age of 20 who are involved in knee-strenuous sport at the index ACL injury constitute a high-risk group in terms of sustaining a subsequent ACL injury. The timing of RTS and recovery of muscle function have been reported to be important aspects to consider in the RTS decision. To our knowledge, no previous study has evaluated these aspects specifically in adolescent patients. The purpose of this study was, therefore, to evaluate the return to knee-strenuous-sport rates, muscle function and subjective knee function among adolescent patients (15–20 years) and adult patients (21–30 years) 8 and 12 months, respectively, after ACL reconstruction. It was hypothesised that no differences in outcome would be found between the age groups at 8 or 12 months after ACL reconstruction. Materials and methods The study was performed as a prospective, observational register study based on data from a rehabilitation outcome 13 register. The register is located in the western part of Sweden and was established in September 2014. At the end of March 2017, the register comprised more than 1,200 patients, of which 560 patients had undergone a unilateral ACL reconstruction and were between 15 and 30 years of age at the time of surgery (Fig. 1). The register consists of two parts: a battery of validated patient-reported outcome measurements (PROMs) and a b (...truncated)