Effect of High-Grade Preoperative Knee Laxity on 6-Year Anterior Cruciate Ligament Reconstruction Outcomes

Editorial Commentary: So Your Knee Has a Big Pivot Shift Before Anterior Cruciate Ligament Surgery-Why Does that Matter???

Control of anterolateral knee laxity has always been a major goal of anterior cruciate ligament (ACL) reconstruction. The recent focus on the anatomy of the anterolateral knee and new studies demonstrating decreased graft failure risk with the additional of lateral procedures to intra-articular ACL reconstruction have given these procedures new relevance. A key question that drives indications is which patients benefit the most from these procedures. Those patients with increased rotational knee laxity, particularly in the absence of a repairable meniscus injury, may be good candidates. ACL injury chronicity, bony anatomy, concomitant anterolateral injury, and other factors all contribute to increased anterolateral knee laxity. This high laxity population is ideal for evaluation of the effectiveness of new methods to control knee laxity and improve outcomes of isolated intra-articular ACL reconstruction.

The Influences of Chronicity and Meniscal Injuries on Pivot Shift in Anterior Cruciate Ligament-Deficient Knees: Quantitative Evaluation Using an Electromagnetic Measurement System

PURPOSE

To investigate the influences of time from injury to surgery and meniscal injuries on knee rotational laxity in anterior cruciate ligament (ACL)-deficient knees using the electromagnetic system retrospectively.

METHODS

Ninety-four unilateral ACL-injured patients (44 male and 50 female, mean age: 27.3 ± 11.8 years) were included. The pivot-shift test was performed before ACL reconstruction, as was a quantitative evaluation using the electromagnetic system to determine tibial acceleration. Patients were divided into 4 groups according to the chronicity: group 1, within 3 months (22 patients); group 2, between 3 and 6 months (29 patients); group 3, between 6 and 12 months (23 patients); and group 4, more than 12 months (20 patients). The presence of meniscal injuries was examined arthroscopically.

RESULTS

The tibial acceleration was significantly greater in group 4. There was a positive correlation between tibial acceleration and the time from injury to surgery (r = 0.47, P = .02). In groups 1, 2 and 3, the tibial acceleration in patients with a lateral meniscal injury was significantly greater than in patients with a medial meniscal injury and without meniscal injury. When patients with lateral meniscal injury were excluded (leaving those with medial meniscus injury or without meniscal injury), group 4 had significantly greater accelerations than other groups.

CONCLUSIONS

In ACL-deficient knees, rotational laxity increased with time and the increased rotational laxity was evident more than 1 year after injury whereas it increased with concomitant lateral meniscal injuries within 1 year after injury.

LEVEL OF EVIDENCE

Ⅳ, diagnostic study of nonconsecutive patients.

Modified Iliotibial Band Tenodesis Is Indicated to Correct Intraoperative Residual Pivot Shift After Anterior Cruciate Ligament Reconstruction Using an Autologous Hamstring Tendon Graft: A Prospective Randomized Controlled Trial

BACKGROUND

The indications for the addition of anterolateral soft tissue augmentation to anterior cruciate ligament (ACL) reconstruction and its effectiveness remain uncertain.

PURPOSE

To determine if modified iliotibial band tenodesis (MITBT) can improve clinical outcomes and reduce the recurrence of ACL ruptures when added to ACL reconstruction in patients with a residual pivot shift.

STUDY DESIGN

Randomized controlled trial; Level of evidence, 2.

METHODS

Patients with a primary ACL rupture satisfying the following inclusion criteria were enrolled: first ACL rupture, involved in pivoting sports, skeletally mature, no meniscal repair performed, and residual pivot shift relative to the contralateral uninjured knee immediately after ACL reconstruction. Patients were randomized to group A (no further surgery) or group B (MITBT added) and were followed up for 2 years. The patient-reported outcome (PRO) measures used were the International Knee Documentation Committee (IKDC) score, Knee injury and Osteoarthritis Outcome Score (KOOS) subscale of sport/recreation (Sport/Rec), KOOS subscale of quality of life (QoL), Lysholm knee score (LKS), Tegner activity scale (TAS), recurrent ACL ruptures, or need for further surgery in either knee. Analysis of variance was used to compare PROs; the Wilcoxon test was used for the TAS; and the chi-square test was used for recurrence of ACL ruptures, meniscal injuries, and contralateral ACL ruptures (P < .05).

RESULTS

A total of 55 patients were randomized: 27 to group A (female:male ratio = 15:12; mean age, 22.3 ± 3.7 years) and 28 to group B (female:male ratio = 17:11; mean age, 21.8 ± 4.1 years). At 2-year follow-up, group A had a similar IKDC score (90.9 ± 10.7 vs 94.2 ± 11.2; respectively; P = .21), lower KOOS Sport/Rec score (91.5 ± 6.4 vs 95.3 ± 4.4, respectively; P = .02), similar KOOS QoL score (92.0 ± 4.8 vs 95.1 ± 4.3, respectively; P = .14), lower LKS score (92.5 ± 4.8 vs 96.8 ± 8.0, respectively; P = .004), lower TAS score (median, 7 [range, 7-9] vs 8 [range, 8-10], respectively; P = .03), higher rate of recurrence (14.8% vs 0.0%, respectively; P < .001), similar rate of meniscal tears (14.8% vs 3.6%, respectively; P = .14), and similar rate of contralateral ACL ruptures (3.7% vs 3.6%, respectively; P = .99) relative to group B.

CONCLUSION

The augmentation of ACL reconstruction with MITBT reduced the risk of recurrent ACL ruptures in knees with a residual pivot shift after ACL reconstruction and improved KOOS Sport/Rec, LKS, and TAS scores.

REGISTRATION

ACTRN12618001043224 (Australian New Zealand Clinical Trials Registry).

Excessive Preoperative Anterior Tibial Subluxation in Extension Is Associated With Inferior Knee Stability After Anatomic Anterior Cruciate Ligament Reconstruction

BACKGROUND

Anterior tibial subluxation (ATS) in extension after anterior cruciate ligament (ACL) injury highlights an increased anterior position of the tibia relative to the femur. Recent studies demonstrated that subluxation is sometimes irreducible and the normal tibiofemoral relationship is not restored by ACL reconstruction (ACLR), which raises concerns regarding clinical outcomes after ACLR.

HYPOTHESIS

Excessive preoperative ATS in extension is associated with inferior knee stability after anatomic ACLR.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

From March 2016 to January 2017, a total of 487 consecutive patients with clinically diagnosed noncontact ACL injuries who underwent primary anatomic ACLR were retrospectively analyzed. Of these patients, 430 met the criteria for inclusion in this study. Anterior subluxation of the lateral and medial compartments (ASLC and ASMC) in extension relative to the femoral condyles was measured on preoperative magnetic resonance imaging. Twenty patients (study group) who demonstrated excessive (>10 mm) ASLC and ASMC in extension were matched 1:2 to 40 participants (control group) who showed minimal or no (<3 mm) ASLC and ASMC in extension. The amount of ASLC and ASMC in extension relative to the femoral condyles at 2 years postoperatively was the primary outcome. Moreover, the Lysholm score, IKDC grade (International Knee Documentation Committee), and stability assessments (pivot-shift test and KT-1000 arthrometer side-to-side difference) were evaluated preoperatively and at the last follow-up visit.

RESULTS

The preoperative mean ASLC and ASMC in extension of the study group were both significantly larger than those of the control group (study group vs control group: ASLC, 13.5 mm vs 1.2 mm; ASMC, 12.4 mm vs 1.0 mm; P < .05). Moreover, patients in the study group showed significantly larger posterior tibial slope than the patients in the control group (17.8°± 2.5° vs 9.5°± 1.5°; P < .05). At the final follow-up visit, the mean ASLC and ASMC of the study group were 8.1 mm and 7.3 mm, which were significantly larger than those of the control group (ASLC, 0.9 mm; ASMC, 0.7 mm; P < .05). In addition, the study group showed inferior knee stability when compared with the control group in terms of both the pivot-shift test (study group vs control group: 2 grade 2, 10 grade 1, and 8 grade 0 vs 1 grade 1 and 39 grade 0; P < .05) and the KT-1000 arthrometer side-to-side difference (study group vs control group: 4.4 ± 1.2 mm vs 1.5 ± 0.6 mm; P < .05). Furthermore, the study group showed significantly lower mean Lysholm score (study group vs control group: 80.3 ± 6.3 vs 93.3 ± 4.3, P < .05) and IKDC grading results (study group vs control group: 3 grade C, 16 grade B, and 1 grade A vs 3 grade B and 37 grade A; P < .05) as compared with the control group.

CONCLUSION

In this short-term study, the excessive (>10 mm) preoperative ATS in extension after ACL injury was associated with inferior knee stability after anatomic ACLR.

Post-traumatic osteoarthritis diagnosed within 5 years following ACL reconstruction

PURPOSE

The purpose was to calculate the incidence of osteoarthritis in individuals following Anterior Cruciate Ligament Reconstruction (ACLR) in a large, national database and to examine the risk factors associated with OA development.

METHODS

A commercially available insurance database was queried to identify new diagnoses of knee OA in patients with ACLR. The cumulative incidence of knee OA diagnoses in patients after ACLR was calculated and stratified by time from reconstruction. Odds ratios were calculated using logistic regression to describe factors associated with a new OA diagnosis including age, sex, BMI, meniscus involvement, osteochondral graft use, and tobacco use.

RESULTS

A total of 10,565 patients with ACLR were identified that did not have an existing diagnosis of OA, 517 of which had a documented new diagnosis of knee OA 5 years after ACL reconstruction. When stratified by follow-up time points, the incidence of a new OA diagnosis within 6 months was 2.3%; within a 1-year follow-up was 4.1%; within 2 years, follow-up was 6.2%, within 3 years, follow-up was 8.4%; within 4 years, follow-up was 10.4%; and within 5 years, follow-up was 12.3%. Risk factors for new OA diagnoses were age (OR 2.44, P < 0.001), sex (OR 1.2, P = 0.002), obesity (OR 1.4, P < 0.001), tobacco use (OR = 1.3, P = 0.001), and meniscal involvement (OR 1.2, P = 0.005).

CONCLUSION

Approximately 12% of patients presenting within 5 years following ACLR are diagnosed with OA. Demographic factors associated with an increased risk of a diagnosis of PTOA within 5 years after ACLR are age, sex, BMI, tobacco use, and concomitant meniscal surgery. Clinicians should be cognizant of these risk factors to develop risk profiles in patients with the common goal to achieve optimal long-term outcomes after ACLR.

LEVEL OF EVIDENCE

III.

Engagement of the Secondary Ligamentous and Meniscal Restraints Relative to the Anterior Cruciate Ligament Predicts Anterior Knee Laxity

BACKGROUND

Patients with high-grade preoperative side-to-side differences in anterior laxity as assessed via the Lachman test after unilateral anterior cruciate ligament (ACL) rupture are at heightened risk of early ACL graft failure. Biomechanical factors that predict preoperative side-to-side differences in anterior laxity are poorly understood.

PURPOSE

To assess, in a cadaveric model, whether the increase in anterior laxity caused by sectioning the ACL (a surrogate for preoperative side-to-side differences in anterior laxity) during a simulated Lachman test is associated with two biomechanical factors: (1) the tibial translation at which the secondary anterior stabilizers, including the remaining ligaments and the menisci, begin to carry force, or engage, relative to that of the ACL or (2) the forces carried by the ACL and secondary stabilizers at the peak applied anterior load.

STUDY DESIGN

Controlled laboratory study.

METHODS

Seventeen fresh-frozen human cadaveric knees underwent Lachman tests simulated through a robotic manipulator with the ACL intact and sectioned. The net forces carried by the ACL and secondary soft tissue stabilizers (the medial meniscus and all remaining ligaments, measured as a whole) were characterized as a function of anterior tibial translation. The engagement points of the ACL (with the ACL intact) and each secondary stabilizer (with the ACL sectioned) were defined as the anterior translation at which they began to carry force, or engaged, during a simulated Lachman test. Then, the relative engagement point of each secondary stabilizer was defined as the difference between the engagement point of each secondary stabilizer and that of the ACL. Linear regressions were performed to test each association (P < .05).

RESULTS

The increase in anterior laxity caused by ACL sectioning was associated with increased relative engagement points of both the secondary ligaments (β = 0.87; P < .001; R² = 0.75) and the medial meniscus (β = 0.66; P < .001; R² = 0.58). Smaller changes in anterior laxity were also associated with increased in situ medial meniscal force at the peak applied load when the ACL was intact (β = -0.06; P < .001; R² = 0.53).

CONCLUSION

The secondary ligaments and the medial meniscus require greater anterior tibial translation to engage (ie, begin to carry force) relative to the ACL in knees with greater changes in anterior laxity after ACL sectioning. Moreover, with the ACL intact, the medial meniscus carries more force in knees with smaller changes in anterior laxity after ACL sectioning.

CLINICAL RELEVANCE

Relative tissue engagement is a new biomechanical measure to characterize in situ function of the ligaments and menisci. This measure may aid in developing more personalized surgical approaches to reduce high rates of ACL graft revision in patients with high-grade laxity.

Factors affecting outcome of ACL reconstruction in over-50-year-olds

INTRODUCTION

With increasing life expectancy and ever-improving quality of life in industrialized countries, functional demand and sports levels are increasing in older subjects, who are thus exposed to central pivot lesions almost as much as younger ones. While non-operative treatment provides acceptable results, it entails significant reduction in sports level. The aim of the present study was to analyze medium-term clinical, functional and radiological results of anterior cruciate ligament (ACL) reconstruction in over-50-year-olds, in order to identify factors for failure.

HYPOTHESIS

The study hypothesis was that surgical management provides good results if patient selection is rigorous.

PATIENTS AND METHODS

A multicenter retrospective study included 398 patients undergoing ACL reconstruction between April 1, 2009 and December 6, 2016. Inclusion criteria comprised: age≥50 years, with proven ACL tear. Preoperatively, clinical work-up was supplemented by measurement of differential anterior laxity and radiologic assessment of cartilage status. Functional level was assessed on the objective IKDC score. Intraoperative data comprised type of graft and meniscal and cartilage status. The same parameters were assessed postoperatively. Functional results were assessed on objective IKDS, KOOS and ACL-RSI scores.

RESULTS

The mean follow-up was 42.2 months. The mean improvement in differential anterior laxity was 4.2mm. Pivot-shift showed improvement, with 97% absent or glide (p<0.001). Objective IKDC score showed significant improvement (p<0.0001). 23% of patients had poor clinical results: IKDC C or D. Preoperative explosive pivot-shift (p<0.0001), medial tibiofemoral osteoarthritis (p<0.0001) and medial meniscus lesion (p<0.002) emerged as risk factors for poor functional outcome.

CONCLUSION

ACL reconstruction in over-50-year-olds provided satisfactory clinical and functional results. Rigorous patient selection is mandatory, as radiologic signs of medial tibiofemoral osteoarthritis indicate a risk of poor outcome. Surgery may be proposed in patients with high functional and athletic demand, before medial meniscal lesions can set in. In case of explosive pivot shift, associated anterolateral reconstruction should be considered.

Combined Reconstruction of the Anterolateral Ligament in Patients With Anterior Cruciate Ligament Injury and Ligamentous Hyperlaxity Leads to Better Clinical Stability and a Lower Failure Rate Than Isolated Anterior Cruciate Ligament Reconstruction

PURPOSE

To compare functional outcomes, residual instability, and rupture rates in patients with ligamentous hyperlaxity undergoing isolated anterior cruciate ligament (ACL) reconstruction or combined ACL and anterolateral ligament (ALL) reconstruction.

METHODS

Two groups of patients were evaluated and compared retrospectively. Both groups consisted of patients with ACL injuries and associated ligamentous hyperlaxity, defined based on the modified Beighton scale with a minimum score of 5. Group 1 patients underwent anatomical ACL reconstruction, and group 2 patients underwent anatomical ACL reconstruction combined with ALL reconstruction. Group 1 consisted of historical controls. The presence of associated meniscal injury, subjective International Knee Documentation Committee and Lysholm functional scores, KT-1000 measurements, the presence of a residual pivot-shift, and the graft rupture rate were evaluated. The study was performed at University of São Paulo in Brazil.

RESULTS

Ninety patients undergoing ACL reconstruction with ligamentous hyperlaxity were evaluated. The mean follow up was 29.6 ± 6.2 months for group 1 and 28.1 ± 4.2 months for group 2 (P = .51). No significant differences were found between the groups regarding Beighton scale, gender, the duration of injury before reconstruction, follow-up time, preoperative instability, or associated meniscal injuries. The mean age was 29.9 ± 8.1 years in group 1 and 27.0 ± 9.1 years in group 2 (P = .017). In the final evaluation, group 2 patients showed better anteroposterior clinical stability as evaluated by KT-1000 arthrometry (P = .02), better rotational stability as evaluated by the pivot-shift test (P = .03) and a lower reconstruction failure rate (21.7% [group 1] vs 3.3% [group 2]; P = .03). Clinical evaluations of postoperative functional scales showed no differences between the 2 groups (P = .27 for International Knee Documentation Committee; P = .41 for Lysholm).

CONCLUSIONS

Combined ACL and ALL reconstruction in patients with ligamentous hyperlaxity resulted in a lower failure rate and improved knee stability parameters compared to isolated ACL reconstruction. No differences were found in the functional scales.

LEVEL OF EVIDENCE

Level III, case control study.