Comparison of Knee Function and Activity Level Between Bilateral and Unilateral ACL Reconstruction: A Matched-Group Analysis With Minimum 5-Year Follow-up

Substantial Variability Exists in Reporting Clinically Significant Outcome Measure Thresholds for Arthroscopic Anterior Cruciate Ligament Reconstruction: A Systematic Review

PURPOSE

To systematically review the reporting of clinically significant outcome measure (CSO) thresholds and methods for calculating thresholds following anterior cruciate ligament (ACL) reconstruction.

METHODS

A systematic review of PubMed, Embase, and Web of Science databases was conducted to identify articles that met inclusion criteria from January 1, 2015, to July 7, 2024. Inclusion criteria included studies reporting CSO thresholds including minimal clinically important difference (MCID), substantial clinical benefit (SCB), or patient acceptable symptomatic state (PASS) for patients following ACL reconstruction with minimum 12-month follow-up. The MINORS criteria was used to assess study quality. Study demographics, patient-reported outcome measures (PROMs), CSO thresholds, and method of CSO calculation were collected.

RESULTS

A total of 56 studies (n=52,292 patients) met the final inclusion criteria. Reported PROMs included International Knee Documentation Committee (IKDC) (n=35 studies), Knee Injury and Osteoarthritis Outcome score (KOOS) (n=33 studies), Tegner (n=20 studies) and Lysholm (n=19 studies) scores. The PASS was reported in 35 studies, MCID in 30, and SCB in 4. Among the studies that reported PASS, the most used threshold calculation was the ROC-Youden index (71.4%, n=25/35). In the studies reporting MCID, the most used threshold calculation was the 0.5 standard deviation (SD) of mean change method (36.7%, n=11/30). The most reported threshold calculation among the SCB studies was the ROC curve analysis (75%, n=3/4). In studies independently calculating CSOs, the most common methods were 0.5 standard deviations (SD) of mean change for MCID (50%, n=10/20), the ROC-Youden index for PASS (73.3%, n=11/15), and ROC curve analysis (75.0%, n=3/4) for SCB. Descriptions of anchor questions were reported in 22 studies (39.3%).

CONCLUSION

Substantial variability exists in the reporting and calculation of MCID, SCB, and PASS for various PROMs following ACL reconstruction.

Analysis of the Swedish Knee Ligament Register: Concomitant injuries, revision surgery and smoking render worse results

PURPOSE

To analyse the 52,199 patients in the Swedish Knee Ligament Register (SKLR) preoperatively, and the patients reaching 5- and 10-year follow-ups who underwent anterior cruciate ligament reconstruction (ACLR), revision ACLR and ACLR on the contralateral side (CACLR). The main hypothesis was that patients undergoing revision ACLR would have worse patient-reported outcome measurements (PROMs) than the primary ACLR group at 10 years and that smoking and concomitant injuries would result in poorer outcomes for all groups.

METHODS

Data from 2005 to 2021 were extracted from the SKLR. Only patients whose ACLR surgery was registered in the SKLR were included for revision ACLR and CACLR. The PROMs consist of the Knee injury and Osteoarthritis Outcome Score (KOOS) and the knee-specific PROM (EQ-5D-3L). PROMs were analysed as a whole and in subgroups based on sex, smoking, graft choice and concomitant injuries.

RESULTS

Poorer KOOS were seen for revisions compared with primary ACLRs at both the 5- and 10-year follow-ups (p = 0.003). Smokers had significantly poorer KOOS than nonsmokers (p < 0.001) preoperatively in all groups, however only in the primary ACLR group at 5 and 10 years. At 10 years, patients who had undergone CACLR had lower KOOS than primary ACLRs (p = 0.03). Concomitant injuries resulted in statistically, significantly poorer KOOS for both primary ACLRs and CACLRs preoperatively and at the follow-ups.

CONCLUSION

The PROMs for revision ACLRs have worse KOOS scores at 10 years compared with the primary ACLRs. The presence of concomitant meniscal or cartilage injuries at the time of ACLR or CACLR were associated with worse PROMs.

LEVEL OF EVIDENCE

Level III.

Revision ACL reconstruction, but not bilateral ACL reconstruction, is associated with clinically relevant inferior subjective knee function compared with primary ACL reconstruction: A comparative analysis of 6831 patients

PURPOSE

To evaluate and compare the subjective knee function in patients undergoing revision and bilateral anterior cruciate ligament (ACL) reconstruction (ACLR) with those undergoing primary ACLR in a large cohort.

METHODS

Patients without concomitant ligament injuries who underwent primary, revision or bilateral ACLR at the Capio Artro Clinic, Stockholm, Sweden, between 2005 and 2018 were identified. The Knee injury and Osteoarthritis Outcome Score (KOOS) was collected preoperatively and at 1, 2 and 5 years postoperatively from the Swedish National Knee Ligament Registry. Patients who underwent revision and bilateral ACLR were compared with those who underwent primary ACLR (control group) using Student's t test.

RESULTS

A total of 6831 patients (6102 with primary ACLRs, 343 with revision ACLRs and 386 with bilateral ACLRs) were included. Preoperatively, there were significant but nonclinically relevant differences in favour of the revision ACLR group for KOOS Symptoms, Pain, Activities of Daily Living (ADL) and Sport/Rec subscale scores compared with the primary ACLR group. Postoperatively, except for the 1-year Symptoms and ADL subscales, the revision ACLR group reported significantly lower scores on all KOOS subscales than the primary ACLR group, with clinically relevant differences (>8-10 points) for the 1-, 2- and 5-year Sport/Rec and Quality of Life (QOL) subscales. The bilateral ACLR group reported significantly, but not clinically relevant, inferior scores on the 1-year Symptoms and QOL subscales and the 5-year Sport/Rec and QOL subscales compared with the primary ACLR group.

CONCLUSIONS

Revision ACLR, but not bilateral ACLR, was associated with clinically relevant inferior subjective knee function compared with primary ACLR. It is important to counsel patients regarding their future subjective knee function after repeated ACLR. Compared to primary ACLR, inferior subjective results should be expected after revision ACLR, but not after bilateral ACLR.

LEVEL OF EVIDENCE

Level III.

Psychological Readiness to Return to Sport (RTS) and RTS Rates Are Similar in Patients After Either Bilateral or Unilateral Anterior Cruciate Ligament Reconstruction

Purpose

To compare psychological readiness to return to sport (RTS), RTS rate, level of return, and time to return between patients who underwent bilateral anterior cruciate ligament reconstruction (ACLR) and those who underwent unilateral ACLR.

Methods

The electronic medical record at a single academic medical center was queried for patients who underwent ACLR from January 2012 to May 2020. The inclusion criteria were skeletally mature patients who underwent either single or sequential bilateral ACLR and who had undergone either the primary ACLR or second contralateral ACLR at least 2 years earlier. Bilateral ACLRs were matched 1:3 to unilateral reconstructions based on age, sex, and body mass index. Psychological readiness to RTS was assessed using the validated ACL Return to Sport After Injury (ACL-RSI) scale. This, along with time to return and level of RTS, was compared between the 2 cohorts.

Results

In total, 170 patients were included, of whom 44 underwent bilateral ACLR and 132 underwent unilateral ACLR. At the time of the first surgical procedure, patients in the unilateral cohort were aged 28.8 ± 9.4 years and those in the bilateral cohort were aged 25.7 ± 9.8 years (P = .06). The average time difference between the first and second surgical procedures was 28.4 ± 22.3 months. There was no difference in psychological readiness to RTS (50.5 in bilateral cohort vs 48.1 in unilateral cohort, P = .66), RTS rate (78.0% in unilateral cohort vs 65.9% in bilateral cohort, P = .16), percentage of return to preinjury sport level (61.2% in unilateral cohort vs 69.0% in bilateral cohort, P = .21), or time to return (41.2 ± 29.3 weeks in unilateral cohort vs 35.2 ± 23.7 weeks in bilateral cohort, P = .31) between the 2 cohorts.

Conclusions

Compared with patients who undergo unilateral ACLR, patients who undergo bilateral ACLR are equally as psychologically ready to RTS, showing equal rates of RTS, time to return, and level of return.

Level of Evidence

Level III, retrospective cohort study.

Poorer patient-reported knee function and quality of life, but not activity level, after revision ACL reconstruction compared with primary ACL reconstruction: a matched-pair analysis with a minimum 5-year follow-up

BACKGROUND

An appropriate method for comparing knee function and activity level between patients with primary and revision anterior cruciate ligament reconstruction (ACLR) is to perform a matched-group analysis. The aim was to assess and compare knee function, knee-related quality of life and activity level between patients with revision ACLR and primary ACLR at a minimum of 5 years of follow-up.

METHODS

Patients aged ≤ 40 years old who underwent revision ACLR between 2010 and 2015 and a matched control group (primary ACLR) (1:1) with age ± 2 years, year of ACLR, sex, and pre-injury sport and Tegner Activity Scale (TAS) were retrospectively identified in our clinic database. The preoperative Knee injury and Osteoarthritis Outcome Score (KOOS) and surgical data were extracted and analyzed. Patients were mailed KOOS and EQ-5D questionnaires at a minimum of 5-years after revision ACLR. Study-specific questions about knee function, limitation in sport, satisfaction, and activity level according to the TAS (all scales of 1-10, 10 best) were also asked by telephone.

RESULTS

Seventy-eight patients with a revision ACLR (mean age ± SD, 29.9 ± 6.0 years) matched with seventy-eight patients with a primary ACLR (30.2 ± 5.8 years) were included. The follow-up for the revision ACLR group was 7.0 ± 1.5 years and for the primary ACLR group 7.7 ± 1.6 years. The revision ACLR group reported poorer KOOS scores in all subscales (p < 0.05) except the Symptoms subscale, poorer EQ-5D VAS (mean 79.2 ± 20.1 vs 86.0 ± 20.1, p = 0.012), and less satisfaction with current knee function (median 7 (6-8) vs 8 (7-9), p < 0.001). Patients with revision ACLR also experienced greater limitation in sports (median 7 (4-8) vs 8 (6-9), p < 0.001). There were no significant differences in the EQ-5D (mean 0.86 ± 0.17 vs 0.89 ± 0.11, p = 0.427), activity level (median 2 (2-5) vs 4 (2-7), p = 0.229), or satisfaction with activity level (median 8 (5-9) vs 8 (6-10), p = 0.281) between the groups.

CONCLUSIONS

At a minimum 5-year follow-up, the revision ACLR group reported poorer knee function and quality of life, less satisfaction with knee function and a greater limitation in sports but no differences in activity level and satisfaction with activity level compared with the primary ACLR group.

Patients who undergo bilateral medial patellofemoral ligament reconstruction return to sport at a similar rate as those that undergo unilateral reconstruction

PURPOSE

Lateral patellar instability is a debilitating condition not only to athletes, but also to a wide range of highly active individuals. Many of these patients experience symptoms bilaterally, though it is unknown how these patients fair with return to sports following a second medial patellofemoral ligament reconstruction (MPFLR). The purpose of this study is to evaluate the rate of return to sport following bilateral MPFLR compared to a unilateral comparison group.

METHODS

Patients who underwent primary MPFLR with minimum 2-year follow-up were identified from 2014 to 2020 at an academic center. Those who underwent primary MPFLR of bilateral knees were identified. Pre-injury sport participation and Tegner score, Kujala score, Visual Analog Score (VAS) for pain, satisfaction, and MPFL-Return to Sport after Injury (MPFL-RSI) scale were collected. Bilateral and unilateral MPFLRs were matched in a 1:2 ratio based on age, sex, body mass index, and concomitant tibial tubercle osteotomy (TTO). A sub-analysis was performed regarding concomitant TTO.

RESULTS

The final cohort consisted of 63 patients, including 21 patients who underwent bilateral MPFLR, matched to 42 unilateral patients at mean follow-up of 47 ± 27 months. Patients who underwent bilateral MPFLR returned to sport at a rate of 62% at a mean of 6.0 ± 2.3 months, compared to a unilateral rate of 72% at 8.1 ± 4.2 months (n.s.). The rate of return to pre-injury level was 43% among bilateral patients and 38% in the unilateral cohort. There were no significant differences in VAS pain, Kujala, current Tegner, satisfaction, and MPFL-RSI scores between cohorts. Approximately half of those (47%) who failed to return to sport cited psychological factors and had significantly lower MPFL-RSI scores (36.6 vs 74.2, p = 0.001).

CONCLUSION

Patients who underwent bilateral MPFLR returned to sports at a similar rate and level compared to a unilateral comparison group. MPFL-RSI was found to be significantly associated with return to sport.

LEVEL OF EVIDENCE

III.