Multiplanar knee kinematics-based test battery helpfully guide return-to-sports decision-making after anterior cruciate ligament reconstruction

The evolution of three-dimensional knee kinematics after ACL reconstruction within one year

Introduction

This study aims to explore the dynamic changes in the six degrees of freedom (6DOF) kinematics of the knee joint in patients within one year after anterior cruciate ligament reconstruction (ACLR), combined with clinical scoring systems to analyze functional recovery characteristics, providing scientific evidence for optimizing postoperative rehabilitation strategies.

Methods

The study enrolled 49 patients followed up at 3 months postoperatively, 33 patients at 6 months, and 35 patients at 12 months. Twenty-nine healthy controls were recruited. A three-dimensional motion capture system was used to collect 6DOF knee kinematic data at 3, 6, and 12 months after surgery, including flexion-extension, internal-external rotation, adduction-abduction angles, and anterior-posterior, distal-proximal, medial-lateral translation data. Clinical function was assessed using the IKDC and KOOS scores. One Way ANOVA of one-dimensional statistical parametric mapping (SPM1D) was used to assess the changes in gait kinematics and differences compared to healthy controls.

Results

After ACLR, the IKDC and KOOS scores of patients significantly improved between 3 and 12 months postoperatively, showing good subjective functional recovery. Over the course of one year, the knee kinematic data of gait has gradually recovered. However, abnormalities in knee joint kinematics still exist. In the coronal plane, the adduction angle of the knee joint during motion is relatively large (p < 0.05); In the sagittal plane, the flexion angle increased during the standing phase (p < 0.05); In the transverse plane, the internal rotation angle of the knee joint increased compared to the controls (p < 0.05). The range of motion of flexion and rotational angles decreased compared to the controls (p < 0.05).

Discussion

The kinematic recovery of the knee joint in ACLR patients presents multidimensional characteristics and dynamic changes. The recovery rates and patterns differ significantly across dimensions, with some abnormalities not fully corrected within one-year post-urgery. These findings provide scientific evidence for individualized rehabilitation strategies, emphasizing the need for strengthening joint stability and range of motion recovery in the early postoperative phase (0-6 months) and focusing on correcting rotational and flexion-extension function during the later phase (6-12 months) to further improve knee function and prevent long-term adverse outcomes.

Efficacy and safety of quadriceps tendon autograft versus bone-patellar tendon-bone and hamstring tendon autografts for anterior cruciate ligament reconstruction: a systematic review and meta-analysis

BACKGROUND

Quadriceps tendon (QT), bone-patellar tendon-bone (BPTB), and hamstring tendon (HT) autografts are widely used for anterior cruciate ligament reconstruction (ACLR), but the optimal autograft choice remains controversial. This study assessed the treatment effects of QT versus BPTB and HT autografts for ACLR.

METHODS

The PubMed, Embase, and Cochrane Library databases were systematically searched for eligible studies published from inception until July 2022. Effect estimates were presented as odds ratios (OR) and weighted mean differences (WMD) with 95% confidence intervals (CI) for categorical and continuous variables, respectively. All pooled analyses were performed using a random-effects model.

RESULTS

Twenty-one studies (3 randomized controlled trials [RCTs], 3 prospective studies, and 15 retrospective studies) involving 2964 patients with ACLR were selected for meta-analysis. Compared with the HT autograft, the QT autograft was associated with a reduced risk of graft failure (OR: 0.46; 95% CI: 0.23-0.93; P = 0.031). Compared with the BPTB autograft, the QT autograft was associated with a reduced risk of donor site pain (OR: 0.16; 95% CI: 0.10-0.24; P < 0.001). Moreover, the QT autograft was associated with a lower side-to-side difference than that observed with the HT autograft (WMD: - 0.74; 95% CI: - 1.47 to - 0.01; P = 0.048). Finally, compared with the BPTB autograft, the QT autograft was associated with a reduced risk of moderate-to-severe kneecap symptoms during sports and work activities (OR: 0.14; 95% CI: 0.05-0.37; P < 0.001).

CONCLUSIONS

The findings of this study suggest that the QT autograft can be defined as a safe and effective alternative choice for ACLR, but its superiority is yet to be proven by RCTs and prospective studies. Level of evidence Level III.

Lower extremity return to sport testing: A systematic review

BACKGROUND

Lower extremity injuries account for an enormous portion of sports medicine cases in the United States each year. Unfortunately, there are no uniform criteria for athletes to complete prior to returning to sport (RTS) following a lower extremity injury. Therefore, the purpose of this systematic review is to review current literature for joint-specific and global lower extremity testing to determine the most valid functional test that can be utilized to reduce the risk of re-injury as athletes RTS.

METHODS

A systematic search of PubMed, PubMed Central, Cochrane Library, OVID, and Embase databases was conducted for studies prior to May 2024 following PRISMA guidelines. ROBINS-I Tool was utilized for the risk of bias assessment.

RESULTS

Of 19,189 studies, 114 (0.6%) studies published prior to May of 2024 met inclusion criteria and were analyzed. Eighty five percent of articles discussed RTS for individuals with knee pathology. Furthermore, 82% specifically analyzed RTS following ACL reconstruction. The most common RTS test was isokinetic dynamometry testing which is seen in 73% of studies. Only 6.2% of studies analyzed RTS for individuals with hip pathology and only two studies analyzed RTS for patients with ankle injuries.

CONCLUSION

Even with the enormous amount of literature that exists regarding ACL injuries and testing there is no standardized criterion for RTS clearance. The suggested test batteries from this review can serve as a framework for future research and validation for joint-specific RTS functional testing.

Comparison between a Novel Knee Arthrometer and Simultaneous Stress Radiography for the Diagnosis of Complete and Partial Acute Anterior Cruciate Ligament Tears

OBJECTIVES

The type of ligamentous tear and the degree of knee laxity have important guiding significance for the diagnosis and management of anterior cruciate ligament (ACL) tears. Instrumental measurement is necessary for ACL tears since physical examination and magnetic resonance imaging (MRI) cannot provide an objective and quantitative assessment of knee laxity. This study aimed to compare the application of a novel knee arthrometer and simultaneous stress radiography in differentiating between complete and partial acute ACL tears, and further assess the correlation between the two measurements.

METHODS

A total of 106 patients with complete acute ACL tears and 52 patients with partial acute ACL tears were included in the study. Preoperative arthrometry and simultaneous stress radiography were performed using the Ligs arthrometer at 90, 120, and 150 N to assess side-to-side difference (SSD) in anterior knee laxity. The optimal threshold was determined using the receiver operating characteristic (ROC) curve. The area under the ROC curve (AUC) was used to assess the diagnostic value of the measurement. Pearson's correlation coefficient was used to assess the correlation between the two measurements.

RESULTS

The optimal differential SSD thresholds in the Ligs arthrometer were 2.7 mm at 90 N, 3.8 mm at 120 N, and 4.6 mm at 150 N. Similarly, the optimal differential SSD thresholds in simultaneous stress radiography were 3.8 mm at 90 N, 5.1 mm at 120 N, and 5.6 mm at 150 N. The AUC analysis revealed that the Ligs arthrometer was fairly informative at 90 N (AUC = 0.851), 120 N (AUC = 0.878), and 150 N (AUC = 0.884), and simultaneous stress radiography was highly informative at 90 N (AUC = 0.910), 120 N (AUC = 0.925), and 150 N (AUC = 0.948). Moreover, the AUC of the combined measurements was 0.914 at 90 N, 0.931 at 120 N, and 0.951 at 150 N. A significantly strong correlation was found between the two measurements at 90 N (r = 0.743, p < 0.001), 120 N (r = 0.802, p < 0.001), and 150 N (r = 0.823, p < 0.001).

CONCLUSIONS

The Ligs arthrometer and simultaneous stress radiography proved to be valid diagnostic tools to differentiate between complete and partial acute ACL tears, with a strong correlation between the two measurements in SSD values. Compared with single instrumental measurement, the combination of the two measurements can further improve the diagnostic value in this regard.

Limb asymmetries persist 6 months after anterior cruciate ligament reconstruction according to the results of a jump test battery

Objectives

Test batteries used to assess a patient's return-to-sports (RTS) following anterior cruciate ligament reconstruction (ACLR) are currently undergoing continual development, although no consensus exist on tests to be administered to athletes before allowing return to play. A simple standardized jump test battery was developed to objectively evaluate knee function following ACLR, thereby aiding in RTS decision-making.

Methods

Thirty-three patients who underwent ACLR were prospectively assessed pre-operatively, 6, and 12 months after surgery. Knee function was assessed using a device for optical detection using a test battery consisting of three jump tests: monopodalic countermovement jump (CMJ), drop jump, and monopodalic side-hop. Limb symmetry index (LSI) was reported for all tests at all time points. LSI ≥90% was defined as RTS criteria.

Results

At 12-month evaluation, mean LSI significantly improved compared to 6-month follow up (p < 0.01), and also compared to baseline (p < 0.01), reporting a mean value of 92.6% for CMJ, 90.6 for drop jump and 96.9% for side hop test. Most patients fulfilled the RTS criteria 12 months after surgery (LSI ≥90%). The percentages of patients demonstrating LSI ≥90% at 6 months was 7/33 (21.2%) for CMJ, 12/33 (36.4%) for drop jump, and 11/33 (33.3%) for side-hop test. One year after surgery, percentages grew up to 66.6% (22/33), 63.6% (21/33), and 81.8% (27/33) respectively.

Conclusion

Six months after ACLR, knee functional performance was unsatisfactory in most patients, whereas a significantly higher percentage of patients met RTS criteria 1 year after surgery. The results of the jump test battery proposed in this study support the idea that timing for resumption of cutting and pivoting sports should be delayed later than 6 months, as still limb asymmetries persist at this time point.

Correlation Between the Location and Distance of Kissing Contusions and Knee Laxity in Acute Noncontact ACL Injury

BACKGROUND

Bone bruise (BB) and kissing contusion are common features of acute anterior cruciate ligament (ACL) injury on magnetic resonance imaging (MRI). The correlation between the location and distance of kissing contusions and knee laxity remains unclear.

PURPOSE

To determine the significance of different patterns of BB in acute noncontact ACL injury and assess the correlation between the location and distance of kissing contusions and the severity of knee laxity.

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

A total of 205 patients with acute noncontact ACL injury undergoing arthroscopic treatment between January 2021 and May 2022 were included in this retrospective analysis. Patients were grouped according to the different patterns of BB. The type of ACL injury and concomitant injuries were analyzed on MRI and confirmed by arthroscopy. Anterior knee laxity was assessed by the Ligs digital arthrometer and stress radiography, and rotational knee laxity was assessed by the intraoperative pivot-shift test. The MRI parameters of the location and distance of kissing contusions were measured to assess their correlations with the severity of knee laxity.

RESULTS

Of the 205 patients with acute noncontact ACL injury, 38 were in the non-BB group and 167 were in the BB group, the latter including 32 with the isolated BB on the lateral tibial plateau and 135 with kissing contusions. There was no significant difference in the mean time from initial injury to MRI scan between the non-BB group and the BB group (14.34 ± 2.92 vs 15.17 ± 2.86 days; P = .109) or between the isolated BB subgroup and the kissing contusion subgroup (14.94 ± 2.92 vs 15.23 ± 2.85 days; P = .605). The side-to-side difference (SSD) in anterior knee laxity and the incidences of complete ACL injury, concomitant injuries, and high-grade pivot-shift test were significantly higher in the BB group than in the non-BB group, and in the kissing contusion subgroup compared with the isolated BB subgroup. The kissing contusion index of the lateral femoral condyle (LFC) and the sagittal distance of kissing contusions were significantly correlated with the SSD in anterior knee laxity and the grade of pivot-shift test (P < .001).

CONCLUSION

The presence of BB, in particular the appearance of kissing contusions, was related to greater knee laxity and higher incidences of complete ACL injury and concomitant injuries in acute noncontact ACL injury. For patients with kissing contusions, as the location of BB on the LFC moved forward and the distance between kissing contusions increased, anterior and rotational knee laxity became more serious.

The validity of the Ligs digital arthrometer at different loads to evaluate complete ACL ruptures

Objective: The Ligs Digital Arthrometer is a recently launched versatile arthrometer that can be used for the quantitative assessment of knee and ankle joint laxity. This study aimed to evaluate the validity of the Ligs Digital Arthrometer for the diagnosis of complete anterior cruciate ligament (ACL) ruptures at different loads.

Materials and Methods: From March 2020 to February 2021, we included 114 normal subjects and 132 subjects diagnosed with complete ACL ruptures by magnetic resonance imaging (MRI) and eventually confirmed by arthroscopy in the study. Anterior knee laxity was independently measured by the same physical therapist using the Ligs Digital Arthrometer. Recorded anterior knee laxity and calculated the side-to-side difference (SSD) at 30, 60, 90, 120, and 150 N loads, respectively. The receiver operating characteristic (ROC) curve was used to determine the optimal laxity threshold, and the diagnostic value was evaluated by the area under the curve (AUC).

Results: The demographic data of the subjects were comparable between the two groups (p &gt; 0.05). The mean values of anterior knee laxity measured by the Ligs Digital Arthrometer between the complete ACL ruptures group and the control group were significantly different at 30, 60, 90, 120, and 150 N loads (p &lt; 0.001 for all). According to the results of ROC curve analysis, the optimal laxity threshold for the diagnosis of complete ACL ruptures was 1.1 mm SSD (Se = 66.7%, Sp = 69.3%) at 30 N, 1.3 mm (Se = 74.2%, Sp = 82.5%) at 60 N, 1.6 mm (Se = 79.5%, Sp = 94.7%) at 90 N, 1.9 mm (Se = 84.1%, Sp = 92.1%) at 120 N and 2.1 mm (Se = 85.6%, Sp = 91.2%) at 150 N. The AUC order at different loads from high to low was 150 N (0.948 [0.923–0.973])&gt;120 N (0.933 [0.903–0.963])&gt;90 N (0.902 [0.862–0.943])&gt;60 N (0.846 [0.799–0.893])&gt;30 N (0.720 [0.657–0.783]).

Conclusion: The Ligs Digital Arthrometer proved to be of high diagnostic value in complete ACL ruptures at 90 N, 120 N, and 150 N loads. The diagnostic value improved with the increase of load in a certain range. Based on the results of this study, as a portable, digital and versatile new arthrometer, the Ligs Digital Arthrometer was a valid and promising tool for diagnosing complete ACL ruptures.