Persistent knee extension deficits are common after anterior cruciate ligament reconstruction: a systematic review and meta-analysis of randomised controlled trials

Inclinometers and Apps Are Better than Goniometers, Measuring Knee Extension Range of Motion in Anterior Cruciate Ligament Patients: Reliability and Minimal Detectable Change for the Three Devices

Knee extension range of motion (ROM) measurement is important in patients with anterior cruciate ligament (ACL) injury. The main objective is to evaluate the reliability and the minimal detectable change (MDC) of three methods of measuring knee extension ROM in ACL patients. The three common goniometric devices were a universal goniometer, an inclinometer, and a smartphone app. During a single-visit, knee extension ROM was measured in both knees of 92 ACL-injured or -reconstructed patients by two testers blinded to the other's measures. Intrarater, interrater, and test-retest intraclass correlation coefficients (ICC2,1) were calculated. Intrarater ICC2,1 was excellent for the three devices ranging from 0.92 to 0.94, with the inclinometer yielding the best results (ICC2,1 = 0.94 [95% confidence interval, CI: 0.91-0.96]). Interrater ICC2,1, however, varied from 0.36 to 0.80. The inclinometer and the smartphone app yielded similar results 0.80 (95% CI: 0.71-0.86) and 0.79 (95% CI: 0.70-0.86), respectively, whereas the universal goniometer was 0.36 (95% CI: 0.17-0.53). Test-retest ICC2,1 for the inclinometer was 0.89 (95% CI: 0.84-0.93), 0.86 (95% CI: 0.79-0.91) for the app, and 0.83 (95% CI:0.74-0.89) for the goniometer. The intrarater, interrater, and test-retest MDC95 values ranged from 2.0 to 3.5, 3.7 to 10.4, and 2.6 to 5.4 degrees, respectively. The goniometer was the least reliable. The inclinometer is the recommended device due to its highest ICC scores among the three devices and ease of use.

Does the timing of anterior cruciate ligament reconstruction surgery affect flexion contracture formation in rats?

BACKGROUND

Anterior cruciate ligament injuries are commonly treated with ligament reconstruction surgery, but post-operative joint contracture is a major complication. The optimal timing for anterior cruciate ligament reconstruction remains controversial, with some clinical studies suggesting that early surgery may increase the risk of joint contractures, while others have found no such association. To clarify this, we investigated the effects of the timing of reconstruction surgery on contracture formation using a rat model.

METHODS

Anterior cruciate ligament-transected rats were divided into groups based on the timing of reconstruction: immediate, early, and delayed (1, 14, and 28 days after transection, respectively). Some anterior cruciate ligament-transected rats did not receive reconstruction surgery. Untreated rats served as controls. At 56 days after ligament transection, we assessed knee extension range of motion before (including both myogenic and arthrogenic factors) and after myotomy (arthrogenic factor only), as well as fibrotic changes in the joint capsule.

FINDING

Anterior cruciate ligament transection alone significantly decreased range of motion before myotomy, but not after myotomy. In all reconstructed groups, both range of motions before and after myotomy were significantly reduced compared to the control, indicating the induction of arthrogenic contracture by reconstruction surgery. Fibrotic changes in the joint capsule were observed in all reconstructed groups, contributing to arthrogenic contracture formation. However, the timing of reconstruction had no effect on range of motions and fibrotic changes in the joint capsule.

INTERPRETATION

Our findings may help guide clinical decision-making regarding the timing of anterior cruciate ligament reconstruction surgery.

Editorial Commentary: Failure to Regain Full Hyperextension After Anterior Cruciate Ligament Reconstruction Is Associated With Inferior Patient Satisfaction and Lower Functional Outcomes Scores, But the Impact on Graft Rupture Rates and Persistent Instability Is Unclear

Up to one half of patients undergoing anterior cruciate ligament reconstruction demonstrate some degree of knee hyperextension in their contralateral limb. In most cases, this is mild (1°-5°), but it is reported that 9% and 0.8% demonstrate moderate (6°-10°) and severe (>10°) degrees of hyperextension. These characteristics pose challenges and considerations for surgical management. This includes the finding that failure to regain full hyperextension is common and is associated with inferior functional outcomes and patient satisfaction, and the juxtaposition that regaining full hyperextension may increase graft rupture and persistent instability rates. Although the pathophysiology of extension deficit is multifactorial, 2 particularly important and modifiable risk factors in this population are notch impingement and arthrogenic muscle inhibition. Strategies to avoid notch impingement include anterior notchplasty and careful consideration of graft size, graft type, and tibial tunnel placement. Arthrogenic muscle inhibition is clinically characterized by extension deficit and quadriceps activation failure. It is reversible in most patients and therefore an important modifiable risk factor. Since failure to regain full hyperextension is associated with inferior outcomes, abolishing extension deficit should be a key objective of surgical treatment and rehabilitation. Concerns regarding the risks of persistent laxity and graft rupture in knee hyperlaxity/hyperextension patients can be mitigated by the addition of anterolateral ligament reconstruction.

Retracted Article: Validity and Reliability of Sensor-based Measures of Lower Limb Range of Motion in Soccer Players: a Cross-sectional Study

Ein Defizit der Beweglichkeit gilt als Risikofaktor für Verletzungen der unteren Extremität im Fußball. Zur Messung des Bewegungsausmaßes (Range of Motion [ROM]) eines Gelenks werden analoge Goniometer verwendet. Zunehmend entwickelte sensorbasierte Verfahren wurden hinsichtlich ihrer Testgüte noch nicht hinreichend untersucht. Ziel dieser Studie war die Bestimmung der Übereinstimmungsvalidität sowie der Intratester- und Intertester-Reliabilität sensorbasierter Messungen des Bewegungsumfangs der unteren Extremität bei Fußballspielern. 36 beschwerdefreie Amateurfußballer (Alter: 26,3 ± 4,7 Jahre) wurden in die Studie eingeschlossen. Aus 5 Physiotherapeuten wurden 3 zufällig bestimmt, um die Messungen durchzuführen. Zwei Tester führten die Messungen (1. ROM Knie aus Langsitz; 2. Streckdefizit Knie aus Langsitz; 3. ROM Knie aus Stand; 4. ROM Sprunggelenk Dorsalextension [DE] während Ausfallschritt; 5. ROM Sprunggelenk Plantarflexion [PF] aus Sitz auf dem Stuhl) mit dem digitalen Sensor durch (Index-Test). Der 3. Tester übernahm die Messungen mit dem analogen Goniometer nach Neutral-Null-Methode mit den Probanden in Rückenlage (Referenzstandard). Zur statistischen Analyse wurden der Pearson-Korrelationskoeffizient r, Bland-Altman-Analysen (BAA) und der Intraklassenkorrelationskoeffizient (ICC) verwendet (p ≤ 0,05). Nur bei den Messungen 4 und 5 zeigten sich in der BAA akzeptable mittlere Differenzen von 8,4° (DE) und −10,2° (PF). Bei Messung 1 lag eine moderate Korrelation (r = 0,582) vor. Die sensorbasierten Messungen des Bewegungsumfangs des Knie- und Sprunggelenks wiesen eine exzellente Intra- und Intertesterreliabilität auf (ICC = 0,949–0,986; ICC = 0,895–0,968). Mit dem hier verwendeten etablierten Referenzstandard zeigten sie jedoch nur eine eingeschränkte Übereinstimmung, was mit den unterschiedlichen Ausgangspositionen von Index-Test und Referenzstandard erklärt werden kann.

Long-term effects of non-weight bearing and immobilization after anterior cruciate ligament reconstruction on joint contracture formation in rats

PURPOSE

Non-weight bearing improves and immobilization worsens contracture induced by anterior cruciate ligament reconstruction (ACLR), but effect persistence after reloading and remobilization remains unclear, and the combined effects of these factors on ACLR-induced contracture are unknown. We aimed to determine 1) whether the effects of short-term (2-week) non-weight bearing or immobilization after ACLR on contracture would be sustained by reloading or remobilization during a 10-week observation period, and 2) how the combination of both interventions compared to the outcome of either alone.

METHODS

We divided 88 ACL-reconstructed male rats into four groups: non-intervention, non-weight bearing, joint immobilization, and both interventions. Interventions were performed for 2 weeks, followed by rearing without intervention. Twelve untreated rats were used as controls. At 2, 4, and 12 weeks post-surgery, we assessed range of motion (ROM) and histological changes.

RESULTS

ACLR resulted in persistent loss of ROM, accompanied by synovial shortening, capsule thickening, and osteophyte formation. Two weeks of non-weight bearing increased ROM and reduced osteophyte size, but the beneficial effects disappeared within 10 weeks after reloading. Two-week immobilization decreased ROM and facilitated synovial shortening. After remobilization, ROM partially recovered but remained below non-intervention levels at 12 weeks. When both interventions were combined, ROM was similar to immobilization alone.

CONCLUSIONS

The beneficial effects of 2-week non-weight bearing on contracture diminished within 10 weeks after reloading. The adverse effects of 2-week immobilization on contracture persisted after 10 weeks of remobilization. The effects of the combined use of both interventions on contracture were primarily determined by immobilization.

The Effects of Corticosteroid Administration and Treadmill Exercise on Marrow Adipose Tissue and Trabecular Bone after Anterior Cruciate Ligament Reconstruction in Rats

We aimed to investigate the effects of short-term corticosteroid administration after anterior cruciate ligament (ACL) reconstruction on marrow adipose tissue (MAT) and trabecular bone mass, as well as to examine whether treadmill exercise can mitigate MAT increase and trabecular bone deterioration caused by corticosteroid. ACL-reconstructed rats were divided into groups: no intervention, daily treadmill exercise (60 min/day), administration of the steroidal drug dexamethasone (250 μg/kg on days 0-5, 7, and 9 post-operatively), or dexamethasone administration combined with treadmill exercise. Untreated rats were served as controls. At day 10 or 30 post-operatively, histological assessments were performed in the proximal tibial epiphysis. MAT accumulation and trabecular bone loss were observed after ACL reconstruction. Dexamethasone promoted MAT accumulation at day 10 post-operatively but did not affect the trabecular bone loss. The MAT accumulation caused by dexamethasone reversed within 21 days after discontinuation. Treadmill exercise did not influence the changes in the MAT and trabecular bone areas. Short-term corticosteroid administration after ACL reconstruction promoted MAT accumulation while not affecting trabecular bone area. The MAT accumulation resulting from corticosteroid administration was reversible after discontinuation. Treadmill exercise could not mitigate the accumulation of MAT caused by corticosteroid administration and did not affect trabecular bone area.

Changes in passive hamstring stiffness after primary anterior cruciate ligament reconstruction: A prospective study with comparison of healthy controls

BACKGROUND

The mechanical properties of knee flexors muscles contribute to reducing anterior cruciate ligament loading. This case-control study evaluated the passive knee flexors stiffness after primary anterior cruciate ligament reconstruction with comparison of healthy controls.

METHODS

After anterior cruciate ligament reconstruction, 88 participants (24.5 [8.6] years, 56,8% males) had two isokinetic tests at 4 and 8 postoperative months with measurement of the passive resistive torque of knee flexors and extensors/flexors strength. In the control group, 44 participants (24.5 [4.3] years, 56,8% males) had one visit with the same procedures. Passive knee flexors stiffness was calculated as the slope of the passive torque-angle curve on the last 10° of knee extension (Nm/°). We investigated the impact of timing and type of surgery (autograft and combined meniscus repair) and persistent knee extension deficits on knee flexors stiffness.

FINDINGS

At 4 and 8 postoperative months, passive knee flexors stiffness was lower on the operated limb than on the non-operated limb (P < 0.001) but both limbs had significant lower values than controls (P < 0.001). Stiffness was positively correlated with knee flexors strength (P < 0.010), and knee flexors stiffness at 4 months was lower in individuals who underwent surgery <6 months from injury (P = 0.040). Knee extension deficit or the type of surgery did not have a significant influence on knee flexors stiffness.

INTERPRETATION

Similarly to neuromuscular factors that are traditionally altered after anterior cruciate ligament reconstruction, evaluating passive knee flexors stiffness changes over time could provide supplementary insights into postoperative muscle recovery.

Complete Arthroscopic Posterior Knee Capsulotomy in Patients With Knee Extension Deficit: Preliminary Results of a Clinical Trial

Background

Guided physiotherapy and surgical arthrolysis are effective in most patients with knee extension deficit. However, in refractory cases, posterior knee capsulotomy may be needed.

Purpose

To assess extension restoration, pain reduction, and functional improvement after arthroscopic complete posterior knee capsulotomy in patients with extension deficit refractory to guided physiotherapy and surgical arthrolysis.

Study Design

Case series; Level of evidence, 4.

Methods

Included were patients with symptomatic asymmetric extension deficit >3° refractory to at least 6 months of guided physiotherapy and initial arthrolysis (15 patients with 12-month follow-up and 8 patients with 24-month follow-up). The mean duration of extension deficit was 24.6 months. An arthroscopic complete posterior knee capsulotomy was performed with transection of the posteromedial, posterolateral and central capsule, and the posterior septum. The primary outcome measure was knee extension, with hyperextension denoted as negative knee extension values. Secondary outcome measures included visual analog scale (VAS) for pain during maximum effort and exercise, International Knee Documentation Committee (IKDC) score, and Knee injury and Osteoarthritis Outcome Score (KOOS).

Results

The mean patient age was 40.0 years (range, 26-70 years); 6 out of 15 patients had developed knee contracture after isolated anterior cruciate ligament reconstruction. The mean knee extension deficit decreased from 16.9° (range, 7° to 45°) preoperatively to -0.2° (range, -5° to 5°) at 12-month follow-up (P = .003) and to -0.3° (range, -5° to 5°) at 24-month follow-up (P = .035). The mean VAS pain score decreased from 3.5 (range, 1-6) preoperatively to 1.1 (range, 0-2) at 12-month follow-up (P = .004) and to 1.5 (range, 0-4) at 24-month follow-up (P = .005). The mean IKDC increased from 37.9 (range, 21-62) preoperatively to 63.9 (range, 46-87) at 12-month follow-up (P < .001) and to 60.9 (range, 39-80) at 24-month follow-up (P = .003). The mean KOOS increased from 45.0 (range, 30-62) preoperatively to 75.3 (range, 49-94) at 12-month follow-up (P < .001) and to 72.3 (range, 49-92) at 24-month follow-up (P = .003). There were no significant differences between 12- and 24-month follow-up in extension deficit or functional outcomes. One patient had a midcalf subcutaneous hematoma 5 weeks postoperatively, requiring evacuation.

Conclusion

Arthroscopic complete posterior knee capsulotomy was able to restore knee extension, reduce pain, and improve function, with 12-month follow-up results sustained at 24-month follow-up.

Registration

NCT05385393 (ClinicalTrials.gov identifier).

Postoperative quadriceps weakness and male sex are risk factors for patellofemoral articular cartilage lesions after anatomical anterior cruciate ligament reconstruction

PURPOSE

Patellofemoral (PF) compartment cartilage lesions are a frequent problem after anterior cruciate ligament (ACL) reconstruction. This study aimed to determine the factors that influence PF cartilage lesions after anatomical ACL reconstruction.

METHODS

This study enrolled a total of 114 patients who did not manifest PF compartment cartilage lesions during anatomical ACL reconstruction and underwent second-look arthroscopy 18 months postoperatively. Arthroscopy using the International Cartilage Repair Society (ICRS) classification was used to assess cartilage lesions. The correlation between surgical findings, radiographic factors, and clinical factors and change of ICRS grade was analysed. Multivariate regression analysis was conducted to reveal the independent risk factors for PF cartilage lesions among patients' demographic data and parameters that correlated with the change of ICRS grade in the correlation analyses.

RESULTS

ICRS grade changes in PF cartilage were significantly correlated with age, sex, quadriceps strength at 1 year postoperatively, hamstrings strength at pre- and 1 year postoperatively, and single leg hop test at 1 year postoperatively. However, no significant correlation was found between the time between injury and surgery, posterior tibial slope angle, pre- and postoperative Tegner activity scale, graft type, initial graft tension, meniscus injury, meniscus injury treatment, pre- and postoperative range of motion, anteroposterior laxity and preoperative quadriceps strength, and the change in ICRS grade. Multivariate regression analysis revealed male (P = 0.019) and quadriceps strength weakness at 1 year postoperatively (P = 0.009) as independent risk factors for PF cartilage lesions.

CONCLUSIONS

Quadriceps strength weakness 1 year after ACL reconstruction and males were correlated with a new PF cartilage lesion after anatomical ACL reconstruction, with no significant correlation between bone-patellar tendon-bone autograft, initial graft tension, or extension deficit and new PF cartilage lesion. Rehabilitation that focuses on quadriceps strength after ACL reconstruction is recommended to prevent new PF cartilage lesions.

LEVEL OF EVIDENCE

Level IV.