When ACL reconstruction does not help: risk factors associated with not achieving the minimal important change for the KOOS Sport/Rec and QoL.

OBJECTIVES: To determine factors associated with not achieving a minimal important change (MIC) in the Knee injury and Osteoarthritis Outcome Score (KOOS) Function in Sport and Recreation (Sport/Rec), and Knee-Related Quality of Life (QoL) subscales 1 year after anterior cruciate ligament reconstruction (ACL-R). METHODS: This study used data from the Swedish National Knee Ligament Registry. Multivariable logistic regression models were used to identify factors associated with not achieving a MIC. The change in the preoperative and postoperative KOOS Sport/Rec and QoL subscale scores were dichotomised based on not achieving MIC for both subscales versus achieving MIC for either one or both subscales. The MICs for the Sport/Rec and QoL subscales were 12.1 and 18.3, respectively, and were used to combine both subscales into a single variable (Sport & QoL). RESULTS: Of 16 131 included patients, 44% did not achieve the MIC for the combined Sport/Rec and QoL subscales 1 year after ACL-R. From the multivariable stepwise logistic regression, older patients (OR 0.91, 95% CI 0.88 to 0.94; p<0.0001), males (OR 0.93, 95% CI 0.87 to 0.99; p=0.034) and patients receiving hamstring tendon autograft ACL-R (OR 0.70, 95% CI 0.60 to 0.81; p<0.0001) had lower odds of not achieving the MIC 1 year after ACL-R compared with younger patients, females and patients receiving patellar tendon autograft. Furthermore, patients with cartilage injuries (OR 1.17, 95% CI 1.09 to 1.27; p<0.0001) and higher pre-operative KOOS Sport/Rec and QoL scores (OR 1.34, 95% CI 1.31 to 1.36; p<0.0001) had higher odds of not achieving the MIC. CONCLUSION: Younger patients, females and patients with cartilage injuries and higher pre-operative Sport/Rec and QoL KOOS scores are less likely to benefit from ACL-R and subsequently, have a lower probability for improved Sport/Rec and QoL scores after ACL-R. Furthermore, graft choice may also affect the risk of not achieving the MIC. LEVEL OF EVIDENCE: Retrospective cohort study, level III.

Better Safe Than Sorry? A Systematic Review with Meta-analysis on Time to Return to Sport After ACL Reconstruction as a Risk Factor for Second ACL Injury.

OBJECTIVE: To compare the time to return to sport (RTS) between patients who did and did not suffer a second anterior cruciate ligament (ACL) injury after ACL reconstruction. DESIGN: Etiology systematic review with meta-analysis. LITERATURE SEARCH: Cochrane Library, Embase, Medline, AMED, and PEDro databases were searched in August 2021 and again in November 2022. STUDY SELECTION CRITERIA: Clinical studies reporting time to RTS after ACL reconstruction and second ACL injury were eligible. DATA SYNTHESIS: We pooled continuous data (time [months] and proportions [%]), with random-effects meta-analyses. Pooled estimates were summarized in forest plots. A qualitative data synthesis was also performed. RESULTS: Twenty-one studies were included in the meta-analysis and 33 in the qualitative synthesis. Pooled incidence of second ACL injury was 16.9% (95% confidence interval [CI]: 12.8, 21.6). Patients who suffered a second ACL injury returned to sport significantly earlier (25 days; 95% CI: 9.5, 40.4) than those who did not suffer another injury. There was no difference in time to RTS for professional athletes who suffered a second ACL injury and those who did not. The certainty of evidence was very low. CONCLUSION: There was very low-certainty evidence that patients who suffered a second ACL injury had returned to sport 25 days earlier than patients who did not have another injury. For professional athletes, there was no difference in time to RTS between athletes who suffered a second ACL injury and athletes who did not. J Orthop Sports Phys Ther 2024;54(3):1-15. Epub 30 November 2023. doi:10.2519/jospt.2023.11977.

No Effect of Return to Sport Test Batteries with and without Psychological PROs on the Risk of a Second ACL Injury: A Critical Assessment of Four Different Test Batteries.

Background: Patients report psychological barriers as important when returning to sport, however, psychological outcome measures are seldom included in return to sport (RTS) assessment. There is a need for clinical trials to integrate psychological patient-reported outcomes (PROs) in return to sport batteries assessing patients treated with ACL reconstruction. Objective: The aim of this study was to determine the association between passing clinical tests of muscle function and psychological PROs and sustaining a second ACL injury in patients who RTS after primary ACL reconstruction. Design: Retrospective Cohort study. Methods: Patients' sex, age, height and weight, and the results of strength and hop tests, as well as answers to PRO's (including Tegner activity scale, the ACL Return to Sport after Injury scale (ACL-RSI) as well as the Quality of Life (QoL) subscale of the Knee injury and Osteoarthritis Outcome Score [KOOS]), were extracted from a rehabilitation-specific registry. Four different test batteries comprising muscle function tests and PROs were created to assess whether patients were ready to RTS. Passing each of the test batteries (yes/no) was used as an independent variable. A multivariable Cox proportional hazard model analysis was performed, with sustaining a second ACL injury (either ipsi- or contralateral; yes/no) within two years of RTS as the dependent variable. Results: A total of 419 patients (male, n=214; 51%) were included, of which 51 (12.2%) suffered a second ACL injury within the first two years after RTS. There were no differences in passing rates in the different RTS test batteries comprising muscle function tests and PROs for patients who suffered a second ACL injury compared to patients who did not. Conclusion: No association between passing the RTS clinical tests batteries comprising muscle function and psychological PROs used, and the risk of a second ACL injury could be found. Level of Evidence: 3©The Author(s).

Effect of Quadriceps and Hamstring Strength Relative to Body Weight on Risk of a Second ACL Injury: A Cohort Study of 835 Patients Who Returned to Sport After ACL Reconstruction.

Background: Anterior cruciate ligament (ACL) injuries are common sports-related injuries with a high risk of reinjury after return to sport (RTS). Rehabilitation aims to regain symmetrical knee strength and function to minimize the risk of a second ACL injury after RTS. Purpose: To determine the effect of absolute quadriceps and hamstring strength, normalized by body weight, on the risk of a second ACL injury during the first 2 years after RTS in patients who have undergone ACL reconstruction (ACLR). Study Design: Cohort study; Level of evidence, 3. Methods: Data from patients after index ACLR at the time of RTS were extracted from a rehabilitation registry-Project ACL. Patients who had performed isokinetic tests for quadriceps and hamstring strength and hop tests before RTS were included. The endpoint was a second ACL injury or a follow-up of 2 years after RTS after ACLR. Results: A total of 835 patients (46% women), with a mean age of 23.9 ± 7.7 years, were included. During the study period, 69 (8.3%) second ACL injuries (ipsilateral and contralateral) occurred. Greater relative quadriceps strength in the injured leg increased the risk of a second ACL injury (relative risk [RR], 1.69 [95% CI, 1.05-2.74]; P = .032). In patients who had recovered symmetrical quadriceps strength (limb symmetry index ≥90%), there was no effect of quadriceps strength on the risk of second ACL injury (RR, 1.33 [95% CI, 0.69-2.56]; P = .39). Quadriceps strength on the healthy side or hamstring strength, regardless of side, had no effect on the risk of a second ACL injury. Conclusion: Greater relative quadriceps strength in the injured leg at the time of RTS after ACLR was associated with an increased risk of a second ACL injury. There was no effect of relative quadriceps strength on the risk of a second ACL injury in patients who had recovered symmetrical quadriceps strength.

Lower rates of return to sport in patients with generalised joint hypermobility two years after ACL reconstruction: a prospective cohort study.

BACKGROUND: Generalised joint hypermobility (GJH) has been associated with an increased risk of suffering an anterior cruciate ligament (ACL) injury. Patients with GJH exhibit lower muscle strength and poorer scores for patient-reported outcomes after ACL reconstruction, compared with patients without GJH. The aim of this study was to examine differences in the percentages of patients who return to sport (RTS) or pre-injury level of activity (RTP), muscle function and patient-reported outcomes at the time of RTS or RTP, as well as the time of RTS or RTP in patients with GJH compared with patients without GJH in the first two years after ACL reconstruction. METHODS: This prospective study used data from an ACL- and rehabilitation-specific register located in Gothenburg, Sweden. Patients aged between 16 and 50, who had a primary ACL injury treated with reconstruction, were included. Data up to two years after ACL reconstruction were used and consisted of achieving RTS and RTP, results from isokinetic muscle function tests for knee extension and flexion and patient-reported outcomes (Knee Self-Efficacy Scale, Knee injury and Osteoarthritis Outcome Score and ACL-Return to Sport after Injury scale) at the time of RTS, as well as the time of RTP. A Beighton Score of ≥ 5/9 was used to define GJH. A Tegner Activity Scale of ≥ 6 was used to define RTS, while a Tegner equal to or above pre-injury level was used to define RTP. RESULTS: A total of 1,198 patients (54.7% women) with a mean age of 28.5 ± 8.6 years were included. A smaller proportion of patients with GJH achieved RTS compared with patients without GJH (49.2% vs. 57.3%, Odds ratio: 0.720, p = 0.041). Furthermore, patients with GJH were marginally less symmetrical on the knee extension strength test, expressed as a Limb Symmetry Index, at the time of RTP compared with patients without GJH (87.3 ± 13.5 vs. 91.7 ± 14.3, Cohen's d = 0.142, p = 0.022). No further differences were found between groups regarding any muscle function tests or patient-reported outcomes. CONCLUSION: A smaller proportion of patients with GJH achieved RTS compared with patients without GJH. Patients with GJH displayed less symmetrical knee extension strength at the time of RTP compared with patients without GJH.

Is absolute or relative knee flexor strength related to patient-reported outcomes in patients treated with ACL reconstruction with a hamstring tendon autograft? An analysis of eccentric Nordic hamstring strength and seated concentric isokinetic strength.

BACKGROUND: There is a need for better understanding of how knee flexor strength influence patient-reported outcomes (PROs) after anterior cruciate ligament (ACL) reconstruction. Our aim was to investigate the relationship between the eccentric NordBord test and the seated concentric Biodex test with PROs, during the first year of rehabilitation after ACL reconstruction with hamstring tendon (HT) autograft. METHODS: Patients with an index ACL reconstruction with an HT autograft participating in a rehabilitation registry were screened for inclusion. Outcomes of interest were the correlation between absolute (N/kg or Nm/kg) and relative (limb symmetry index) knee flexor strength measured in the NordBord and Biodex with the results of PROs. The significance level was set at p < 0.05 and Pearson's correlation coefficient was used. RESULTS: 137 patients were included (47% women) with a mean age of 24.8 ± 8.4 years. There were non-significant and weak correlations between relative strength for all PROs. Significant and weak correlations between absolute strength in the Biodex with the Knee Self-Efficacy Scale18 (K-SES18) present at 4 and 8 months, and for the ACL-Return to Sport after Injury scale (ACL-RSI) at 12 months was observed, accounting for 8.4-15.7% of the variance. Significant and weak correlations between absolute strength in the Nordbord with the Knee injury and Osteoarthritis Outcome Scale subscale Sports and Recreation at 4 months, the K-SES18 present and the ACL-RSI at 8 months were observed, accounting for 9.4-14.4% of the variance. CONCLUSION: Absolute knee flexor strength relative to bodyweight for both the Biodex and NordBord test appeared to have a stronger relationship with perceived knee function than relative knee flexor strength, although the observed correlations were weak.

When context creates uncertainty: experiences of patients who choose rehabilitation as a treatment after an ACL injury.

Up to 50% of patients who suffer an anterior cruciate ligament (ACL) injury receive or opt for rehabilitation alone as initial treatment in Scandinavia. Knowledge of whether patients treated with rehabilitation alone after ACL injury are satisfied is lacking. This study aimed to explore the experiences of patients treated with rehabilitation alone after an ACL injury. Fourteen patients (35.9 (19-56) years old) who suffered an ACL injury treated with rehabilitation alone, a mean of 32 months before inclusion, were interviewed. The interview transcripts were analysed using qualitative content analysis with an inductive approach. The experiences of patients treated with rehabilitation after an ACL injury were summarised in one theme: 'Is the grass greener on the other side? Context characterised by uncertainty', supported by three main categories and nine subcategories. Uncertainty permeated the context of all levels of knee-related life following ACL injury: (1) in the past, patients felt uncertainty regarding treatment choices, (2) in the present, patients felt uncertainty regarding their physical capacity and knee self-efficacy, and (3) for the future, patients felt uncertainty regarding what might happen. With few exceptions, patients' experiences after an ACL injury treated with rehabilitation alone are characterised by uncertainty regarding their physical function, psychological impairments and possible future limitation of knee function. Uncertainty is experienced by patients in the past, the present and the future. Patients experience the knee as a symptomatic obstacle and need to adapt the physical activity to the presence of symptoms.

Psychological Patient-reported Outcomes Cannot Predict a Second Anterior Cruciate Ligament Injury in Patients who Return to Sports after an Anterior Cruciate Ligament Reconstruction.

Background: Psychological patient-reported outcomes (PROs) are recommended for use in test batteries to aid in decision-making, regarding whether patients are well prepared to return to sports (RTS) after anterior cruciate ligament (ACL) reconstruction. However, the values that should be regarded as "pass" or "fail" are still unclear. Purpose: This study aimed to identify cut-off values for three commonly used psychological PROs that could differentiate patients who suffer a second ACL injury from patients who do not within two years of RTS in patients after ACL reconstruction with respect to recovery of symmetrical quadriceps strength. Study design: Diagnostic/prognostic study. Methods: Demographic data, isokinetic strength test data for quadriceps, as well as results for the ACL-Return to Sport after Injury scale (ACL-RSI), Knee Injury and Osteoarthritis Outcome Score (KOOS) Quality of Life, and Function in Sport and Recreation sub-scales, and the 18-item version of the Knee Self-Efficacy Scale (K-SES18) were extracted from a registry. Receiver operating characteristic (ROC) curves were calculated for each PRO. Accuracy of the cut-offs was presented with two summary measures for the ROC: the area under the curve (AUC) and Youden index. Results: In total, 641 (355 men, 61%) patients (24.8 [SD 7.6] year old at ACL reconstruction) were included. The cut-off values were not able to differentiate patients who suffered a second ACL injury up to 24 months after RTS and ACL reconstruction from patients who did not. Additionally, achieving symmetrical quadriceps strength did not improve the cut-off psychometric properties. Conclusion: Since cut-off values could not differentiate between patients who suffered a second ACL injury and those who did not, clinicians should not rely only on cut-off values or a single PRO of those analyzed in this study when making decisions on which patients are at risk of experiencing a second ACL injury when returning to sports after ACL reconstruction. Level of Evidence: Level 3.

Persistent knee flexor strength deficits identified through the NordBord eccentric test not seen with "gold standard" isokinetic concentric testing during the first year after anterior cruciate ligament reconstruction with a hamstring tendon autograft.

OBJECTIVE: To investigate the recovery of knee flexor muscle strength evaluated with a Nordic hamstring eccentric test (NordBord) compared with an isokinetic concentric test (Biodex) during the first year after anterior cruciate ligament (ACL) reconstruction using a hamstring tendon autograft. DESIGN: Prospective observational registry study; level of evidence, 3. SETTING: Primary care. PARTICIPANTS: Cross-sectional data of 127 patients (45% women, mean age 24.9 ± 8.1 years) were extracted from a rehabilitation outcome registry at 10 weeks and 4, 8 and 12 months after ACL reconstruction with hamstring tendon autograft. MAIN OUTCOME MEASURES: All patients performed a concentric Biodex test, and an eccentric NordBord test on the same occasion or within seven days of the concentric test. The primary outcome was the limb symmetry index between the respective tests. RESULTS: A greater knee flexor symmetry deficit was observed with the eccentric test compared with the concentric test at all follow-ups with clinically relevant differences at 4 (11.8% ± 12.7% [CI 7.8-15.8%]) and 8 months (13.4 ± 11.9 [CI 9.7-17.2%]. CONCLUSION: The eccentric NordBord test was able to identify clinically relevant deficits in knee flexor strength symmetry that were not identified by gold standard isokinetic concentric testing during the first year among patients treated with an ACL reconstruction using a hamstring tendon autograft.