Does ACL reconstruction alter natural history?: A systematic literature review of long-term outcomes

Two-Year Functional Outcomes of Nonsurgical Treatment in Concomitant Anterior Cruciate Ligament and Medial Collateral Ligament Injuries: A Case-Control Study

The anterior cruciate ligament (ACL) is a common knee injury in high-intensity sports, which can cause early career loss in young athletes. Concomitant damage to other knee stabilizers may occur, such as the medial collateral ligament (MCL). Recent studies have shown that knee stability can increase without surgical intervention in patients with ACL and MCL injuries. Regarding the importance of functional tests in return to exercise prediction, this study aims to measure nonsurgical approach's long-term outcome for concomitant ACL and MCL injuries with a focus on functional tests. This is a case-control study with a 2-year follow-up. The case group consisted of patients who had provided written consent and completed their 2-year follow-up, and the control group was made up of healthy people who did not have any knee medical conditions and were matched by age, gender, and activity level. Physical examinations, Tegner and International Knee Documentation Committee questionnaires, and knee magnetic resonance imaging were conducted, and functional performance tests were performed after a 10-minute warm-up. Lody's index (the ratio of injured-to-uninjured knee results) was calculated. The data were analyzed using independent t-test, one-way analysis of variance, chi-squared test, and Fisher's exact test. The study involved 11 patients in each concomitant ACL and MCL injury cases and healthy control groups with a mean age of 32.4 and 28 years, respectively. None of the patients reported knee instability symptoms in the 2-year follow-up. More than half of the patients continued their sports field without reinjury, with no significant difference in activity levels between case and control groups. The 6-meter hop test and single-leg hop test showed no significant difference between case and control groups (p-value: 0.326, 0.859), and no significant difference was observed in the three Carioca, cocontraction, and Shuttle tests in the 2-year follow-up. Functional tests in ACL and MCL injuries revealed normal outcomes, implying a nonsurgical approach for patients with proximal ACL tears, better knee stability, and no significant differences between the injured and control groups.

The Effect of Supplementary Staple Fixation on Biomechanical Properties of Soft Tissue Graft Tibial Fixation in Anterior Cruciate Ligament Reconstruction

This study aimed to test and compare the biomechanical properties of three tibial fixation methods of anterior cruciate ligament (ACL) tendon grafts under cyclic load and load-to-failure testing in the bovine proximal tibiae, comprising (1) staple fixation alone, (2) interference screw fixation alone, and (3) interference screw fixation with a supplementary staple. Twenty-four bovine tibiae used in the study were divided into three groups (eight proximal tibiae in each group) based on tibial fixation methods of ACL tendon grafts: group A (a spiked ligament staple alone), group B (a cannulated interference screw alone), and group C (a cannulated interference screw with a supplementary staple). Each graft fixation was exposed to cyclic loading conditions. Significant differences were determined in failure load among the three groups (p = 0.008). The mean failure load was significantly higher in group B (717.04 ± 218.51 N) than in group A (308.03 ± 17.22 N) (p = 0.006). No significant differences were observed among the groups regarding axial stiffness (p = 0.442). Cyclic displacement differed significantly among the three groups (p = 0.005). In pairwise comparisons, the mean cyclic displacement was significantly higher in group A (8.22 ± 3.24 mm) compared with group C (1.49 ± 0.41 mm) (p = 0.005). Failure displacement varied considerably among the groups (p = 0.037). Although group B (15.53 ± 6.43 mm) exhibited a greater mean failure displacement than both group A (4.9 ± 0.75 mm) and group C (8.84 ± 4.65 mm), these differences did not reach statistical significance (p = 0.602 and p = 0.329, respectively). Interference screw fixation alone and supplementary staple fixation have biomechanically similar characteristics in terms of initial strength and stiffness of tibial ACL soft tissue graft fixation. Regardless of staple use, an interference screw with the same diameter as the tibial tunnel can ensure sufficient tensile strength in tibial ACL graft fixation.

Rehabilitation and Return to Sport After Anterior Cruciate Ligament Reconstruction

Rehabilitation after an anterior cruciate ligament (ACL) reconstruction requires patience, devotion, and discipline. Rehabilitation should be individualized to each patient's specific need and sport. Return to sport is a continuum throughout the rehabilitation, and patients should not return to performance before passing a battery of muscle function tests and patient-reported outcomes, as well as change of direction-specific tests. Return to full participation should be an agreement between the patient, physical therapist, surgeon, and coach. For minimal risk for second ACL injury, patients should continue with maintenance and prevention training even after returning to sport.

Obesity, Metabolic Syndrome, and Osteoarthritis Require Integrative Understanding and Management

Osteoarthritis (OA) is a progressive chronic disease affecting the articular joints, leading to pain and disability. Unlike traditional views that primarily link OA to aging, recent understanding portrays it as a multifactorial degenerative disease of the entire joint. Emerging research highlights metabolic and immune dysregulation in OA pathogenesis, emphasizing the roles of obesity, dyslipidemia, and insulin resistance in altering joint homeostasis. Recent studies have increasingly focused on the complex role of white adipose tissue (WAT) in OA. WAT not only serves metabolic functions but also plays a critical role in systemic inflammation through the release of various adipokines. These adipokines, including leptin and adiponectin, have been implicated in exacerbating cartilage erosion and promoting inflammatory pathways within joint tissues. The overlapping global crises of obesity and metabolic syndrome have significantly impacted joint health. Obesity, now understood to contribute to mechanical joint overload and metabolic dysregulation, heightens the risk of developing OA, particularly in the knee. Metabolic syndrome compounds these risks by inducing chronic inflammation and altering macrophage activity within the joints. The multifaceted effects of obesity and metabolic syndrome extend beyond simple joint loading. These conditions disrupt normal joint function by modifying tissue composition, promoting inflammatory macrophage polarization, and impairing chondrocyte metabolism. These changes contribute to OA progression, highlighting the need for targeted therapeutic strategies that address both the mechanical and biochemical aspects of the disease. Recent advances in understanding the molecular pathways involved in OA suggest potential therapeutic targets. Interventions that modulate macrophage polarization, improve chondrocyte function, or normalize adipokine levels could serve as preventative or disease-modifying therapies. Exploring the role of diet, exercise, and pharmacological interventions in modulating these pathways offers promising avenues for reducing the burden of OA. Furthermore, such methods could prove cost-effective, avoiding the increase in access to healthcare.

Impact of Surgical Timing on Functional Outcomes after Anterior Cruciate Ligament Reconstruction

Objectives: Although acute anterior cruciate ligament reconstruction (ACLR) is often avoided because of postoperative joint stiffness, delayed ACLR can lead to a longer recovery time and can have a negative impact on physical function due to detraining. This study aimed to determine the effects of acute ACLR on postoperative outcomes, including muscle strength, performance, and return to sports. Methods: A total of 110 patients who underwent anatomical ACLR using hamstring autografts were included in this study and were divided into three groups: acute (ACLR performed within 2 weeks after ACL injury), 2-6 weeks (ACLR performed between 2 and 6 weeks after injury), and 6-12 weeks (ACLR performed between 6 and 12 weeks after injury). Several parameters were evaluated, including range of motion, knee joint stability, isokinetic knee strength, performance, and return to sports. Results: No significant differences were found in the range of motion or knee joint stability between the groups. The acute group exhibited significantly greater quadriceps strength at 3 months postoperatively than the other groups (p < 0.05). The single-leg hop test showed that 66.7%, 38.7%, and 33.3% of the patients in the acute, 2-6 weeks, and 6-12 weeks groups, respectively, recovered to an LSI of 90% or greater (p = 0.09, Cramer's V = 0.27). All patients in the acute group were able to return to sports (p = 0.14; Cramer's V = 0.28). Conclusions: Acute ACLR is advantageous for the early recovery of strength and performance without adverse events. Acute ACLR may shorten the time spent away from sports activities.

Nonoperative Treatment as an Option for Isolated Anterior Cruciate Ligament Injury: A Systematic Review and Meta-analysis

Background

An anterior cruciate ligament (ACL) tear is a risk factor for early osteoarthritis (OA) onset. Generally, ACL reconstruction (ACLR) is associated with better outcomes. However, there is a lack of evidence regarding the effect of operative versus nonoperative treatment for preventing premature knee OA in isolated ACL tears while achieving good functional outcomes.

Purpose/Hypothesis

The purpose of the study was to compare the outcomes of ACLR to primarily nonoperative management of isolated ACL tears. It was hypothesized that the outcomes between treatment types would be similar.

Study Design

Systematic review; Level of evidence, 3.

Methods

This systematic review was registered on the International Prospective Register of Systematic Reviews (PROSPERO) (registration No. CRD42021285901) and was conducted according to the Cochrane Handbook guidelines. We systematically searched for randomized and nonrandomized studies that compared ACLR with nonoperative treatments in isolated ACL tears in 3 databases until October 25, 2021. The risk of bias and quality of evidence of the included studies was assessed in accordance with the Cochrane guidelines. The primary outcome was radiologic signs of OA, and the secondary outcomes were functional parameters. Using the common effects model, we calculated pooled mean differences (MDs) and odds ratios (ORs) with 95% CIs.

Results

Five studies-2 randomized controlled trials (RCTs) and 3 retrospective non-RCTs-were included. There was a moderate risk of bias in 2 studies and a serious risk of bias in 1 study. The quality of evidence was rated low because of the higher risk of bias and inconsistency. Nonoperatively treated knees showed a trend toward lower odds of developing radiological signs of OA (OR, 1.84 [95% CI, 0.90 to 3.75]); however, surgically reconstructed knees had significantly better stability (MD, -2.44 [95% CI, -3.21 to -1.66 ]) and a trend toward better but clinically not meaningful Lysholm scores (MD, 2.88 [95% CI, -1.09 to 6.85]). The qualitative synthesis showed that surgical reconstruction was protective against subsequent injuries but not superior when returning to previous activity levels or various functional tests.

Conclusion

Findings indicated that there is no certain evidence that ACLR for an isolated ACL tear is superior to nonoperative treatment. Clinicians should consider nonoperative treatments with a well-designed rehabilitative program as a primary option. However, these findings must be interpreted with caution because of low study quality and high risk of bias.

Inflammatory mechanisms in post-traumatic osteoarthritis: a role for CaMKK2

Post-traumatic osteoarthritis (PTOA) is a multifactorial disease of the cartilage, synovium, and subchondral bone resulting from direct joint trauma and altered joint mechanics after traumatic injury. There are no current disease-modifying therapies for PTOA, and early surgical interventions focused on stabilizing the joint do not halt disease progression. Chronic pain and functional disability negatively affect the quality of life and take an economic toll on affected patients. While multiple mechanisms are at play in disease progression, joint inflammation is a key contributor. Impact-induced mitochondrial dysfunction and cell death or altered joint mechanics after trauma culminate in inflammatory cytokine release from synoviocytes and chondrocytes, cartilage catabolism, suppression of cartilage anabolism, synovitis, and subchondral bone disease, highlighting the complexity of the disease. Current understanding of the cellular and molecular mechanisms underlying the disease pathology has allowed for the investigation of a variety of therapeutic strategies that target unique apoptotic and/or inflammatory processes in the joint. This review provides a concise overview of the inflammatory and apoptotic mechanisms underlying PTOA pathogenesis and identifies potential therapeutic targets to mitigate disease progression. We highlight Ca2+/calmodulin-dependent protein kinase kinase 2 (CaMKK2), a serine/threonine protein kinase that was recently identified to play a role in murine and human osteoarthritis pathogenesis by coordinating chondrocyte inflammatory responses and apoptosis. Given its additional effects in regulating macrophage inflammatory signaling and bone remodeling, CaMKK2 emerges as a promising disease-modifying therapeutic target against PTOA.

More anterior placement of femoral tunnel position in ACL-R is associated with postoperative meniscus tears

PURPOSE

The purpose of this study was to investigate the relationship between tunnel position in ACL reconstruction (ACL-R) and postoperative meniscus tears.

METHODS

This was a single institution, case-control study of 170 patients status-post ACL-R (2010-2019) separated into two matched groups (sex, age, BMI, graft type). Group 1-symptomatic, operative meniscus tears (both de novo and recurrent) after ACL-R. Group 2-no postoperative meniscus tears. Femoral and tibial tunnel positions were measured by 2 authors via lateral knee radiographs that were used to measure two ratios (a/t and b/h). Ratio a/t was defined as distance from the tunnel center to dorsal most subchondral contour of the lateral femoral condyle (a) divided by total sagittal diameter of the lateral condyle along Blumensaat's line (t). The ratio b/h was defined as distance between the tunnel and Blumensaat's line (b) divided by maximum intercondylar notch height (h). Wilcoxon sign-ranks paired test was used to compare measurements between groups (alpha set at p < 0.05).

RESULTS

Group 1 had average follow up of 45 months and Group 2 had average follow up of 22 months. There were no significant demographic differences between Groups 1 and 2. Group 1-a/t was 32.0% (± 10.2), which was significantly more anterior than group 2, 29.3% (± 7.3; p < 0.05). There was no difference in average femoral tunnel ratio b/h or tibial tunnel placement between groups.

CONCLUSIONS

A relationship exists between more anterior/less anatomic femoral tunnel position and the presence of recurrent or de novo, operative meniscus tears after ACL-R. Surgeons performing ACL-R should strive for recreation of native anatomy via proper tunnel placement to maximize postoperative outcomes.

LEVEL OF EVIDENCE

Level III.

Management after acute rupture of the anterior cruciate ligament (ACL). Part 1: ACL reconstruction has a protective effect on secondary meniscus and cartilage lesions

PURPOSE

The aim of this consensus project was to validate which endogenous and exogenous factors contribute to the development of post-traumatic osteoarthritis and to what extent ACL (anterior cruciate ligament) reconstruction can prevent secondary damage to the knee joint. Based on these findings, an algorithm for the management after ACL rupture should be established.

METHODS

The consensus project was initiated by the Ligament Injuries Committee of the German Knee Society (Deutsche Kniegesellschaft, DKG). A modified Delphi process was used to answer scientific questions. This process was based on key topic complexes previously formed during an initial face-to-face meeting of the steering group with the expert group. For each key topic, a comprehensive review of available literature was performed by the steering group. The results of the literature review were sent to the rating group with the option to give anonymous comments until a final consensus voting was performed. Consensus was defined a-priori as eighty percent agreement.

RESULTS

Of the 17 final statements, 15 achieved consensus, and 2 have not reached consensus. Results of the consensus were summarized in an algorithm for the management after ACL rupture (infographic/Fig. 2).

CONCLUSION

This consensus process has shown that the development of post-traumatic osteoarthritis is a complex multifactorial process. Exogenous (primary and secondary meniscus lesions) and endogenous factors (varus deformity) play a decisive role. Due to the complex interplay of these factors, an ACL reconstruction cannot always halt post-traumatic osteoarthritis of the knee. However, there is evidence that ACL reconstruction can prevent secondary joint damage such as meniscus lesions and that the success of meniscus repair is higher with simultaneous ACL reconstruction. Therefore, we recommend ACL reconstruction in case of a combined injury of the ACL and a meniscus lesion which is suitable for repair.

LEVEL OF EVIDENCE

Level V.

The Effects of Different Management Strategies or Rehabilitation Approaches on Knee Joint Structural and Molecular Biomarkers Following Traumatic Knee Injury: A Systematic Review of Randomized Controlled Trials for the OPTIKNEE Consensus

OBJECTIVE: To summarize the effectiveness of management strategies and rehabilitation approaches for knee joint structural and molecular biomarker outcomes following anterior cruciate ligament (ACL) and/or meniscal tear. DESIGN: Intervention systematic review. LITERATURE SEARCH: We searched the MEDLINE, Embase, CINAHL, CENTRAL, and SPORTDiscus databases from their inception up to November 3, 2021. STUDY SELECTION CRITERIA: We included randomized controlled trials (RCTs) investigating the effectiveness of management strategies or rehabilitation approaches for structural/molecular biomarkers of knee joint health following ACL and/or meniscal tear. DATA SYNTHESIS: We included 5 RCTs (9 papers) with primary ACL tear (n = 365). Two RCTs compared initial management strategies (rehabilitation plus early vs optional delayed ACL surgery), reporting on structural biomarkers (radiographic osteoarthritis, cartilage thickness, meniscal damage) in 5 papers and molecular biomarkers (inflammation, cartilage turnover) in 1 paper. Three RCTs compared different post-ACL reconstruction (ACLR) rehabilitation approaches (high vs low intensity plyometric exercises, accelerated vs nonaccelerated rehabilitation, continuous passive vs active motion), reporting on structural biomarkers (joint space narrowing) in 1 paper and molecular biomarkers (inflammation, cartilage turnover) in 2 papers. RESULTS: There were no differences in structural or molecular biomarkers between post-ACLR rehabilitation approaches. One RCT comparing initial management strategies demonstrated that rehabilitation plus early ACLR was associated with greater patellofemoral cartilage thinning, elevated inflammatory cytokine response, and reduced incidence of medial meniscal damage over 5 years compared to rehabilitation with no/delayed ACLR. CONCLUSION: Very low-certainty evidence suggests that different initial management strategies (rehabilitation plus early vs optional delayed ACL surgery) but not postoperative rehabilitation approaches may influence the incidence of meniscal damage, patellofemoral cartilage loss and cytokine concentrations over 5 years post-ACL tear. J Orthop Sports Phys Ther 2023;53(4):1-22. Epub: 20 February 2023. doi:10.2519/jospt.2023.11576.

Analyses of associated factors with concomitant meniscal injury and irreparable meniscal tear at primary anterior cruciate ligament reconstruction in young patients

Purpose

Although several factors related to the concomitant meniscal injury at anterior cruciate ligament reconstruction (ACL-R) have been investigated in a general population, few studies have identified the risk factors of meniscal tear severity in young patients in which the majority of ACL tears occur. The purpose of this study was to analyze the associated factors with meniscal injury and irreparable meniscal tear and the timeline for medial meniscal injury at ACL-R in young patients.

Methods

A retrospective analysis of young patients (13 to 29 years of age) who underwent ACL-R by a single surgeon from 2005 to 2017 was conducted. Predictor variables (age, sex,body mass index [BMI], time from injury to surgery [TS], and pre-injury Tegner activity level) for meniscal injury and irreparable meniscal tear were analyzed with multivariate logistic.

Results

Four hundred and seventy-three consecutive patients with an average of 31.2 months post-operative follow-up were enrolled in this study. The risk factors for medial meniscus injury were TS (<= 3 months) (odds ratio [OR], 3.915; 95% CI, 2.630-5.827; P < .0001) and higher BMI (OR, 1.062; 95% CI, 1.002-1.125; P = 0.0439). The presence of irreparable medial meniscal tears correlated with higher BMI (OR, 1.104; 95% CI, 1.011-1.205; P = 0.0281).

Conclusion

An increased time from ACL tear to surgery of 3 months was strongly associated with an increased risk of medial meniscus injury, but not related to irreparable medial meniscal tear at primary ACL reconstruction in young patients.

Level of Evidence

Level IV.

Degenerative changes through MR cartilage mapping in anterior cruciate ligament-reconstructed knees

Background

Anterior cruciate ligament (ACL) injury increases risk for post traumatic knee osteoarthritis. ACL injury causes lack of knee stability and frequently requires ACL-reconstruction (ACLR) in order to restore functional and anatomical joint stability. Magnetic resonance imaging with T2 mapping sequence is used to quantify the amount of water content in articular cartilage hence; it is considered a better tool and more beneficial than radiographic based assessment in early detection even before being symptomatic. The aim of work is to estimate the incidence of subclinical degenerative changes that happened early in patients who underwent ACL reconstruction and to identify the correlations of T2 mapping values with patients' BMI, meniscal state/operations, ACL graft assessment and presence of ACLR related complications.

Results

The study was conducted upon 71 patients, divided into 61 anterior cruciate ligament reconstructed knees and 10 control cases using 1.5 T MRI. Assessment of cartilage sub-compartment T2 values and comparison with average normal cartilage T2 values obtained from the control group. Multiple correlations of the grade of articular cartilage degeneration within anterior cruciate ligament reconstructed knees with Body Mass Index (BMI), time of operation as well associated meniscal operations and anterior cruciate ligament graft complications.

Conclusions

Adding the T2 cartilage mapping sequence improves the ability to detect subclinical early degenerative articular cartilage changes in patients who underwent anterior cruciate ligament reconstruction, taking into consideration the relation of the patients' BMI, previous meniscal injuries/operation, ACL graft status and related graft complications with the T2 cartilage mapping values.

Understanding Fear after an Anterior Cruciate Ligament Injury: A Qualitative Thematic Analysis Using the Common-Sense Model

Fear is a significant factor affecting successful return to sport following an anterior cruciate ligament (ACL) injury. However, there is a lack of understanding of the emotional drivers of fear and how fear beliefs are formed. This study qualitatively explored the contextual and emotional underpinnings of fear and how these beliefs were formed, with reference to the Common-Sense Model of Self-Regulation. Face-to-face online interviews were conducted with ACL-injured participants (n = 18, 72% female) with a mean age of 28 years (range 18-50 years). Participants were either 1 year post ACL reconstruction surgery (n = 16) or at least 1 year post injury without surgery (n = 2) and scored above average on a modified Tampa Scale of Kinesiophobia. Four participants were playing state-level sport or higher. Five themes emerged describing factors contributing to fear: 'External messages', 'Difficulty of the ACL rehabilitation journey', 'Threat to identity and independence', 'Socioeconomic factors', and 'Ongoing psychological barriers'. A sixth theme, 'Positive coping strategies', provided insight into influences that could reduce fear and resolve negative behaviors. This study identified a broad range of contextual biopsychosocial factors which contribute to fear, supporting the notion that ACL injuries should not be treated through a purely physical lens. Furthermore, aligning the themes to the common-sense model provided a conceptual framework conveying the inter-related, emergent nature of the identified themes. The framework provides clinicians with a means to understanding fear after an ACL injury. This could guide assessment and patient education.

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

PURPOSE

Knee extension deficits complicate recovery from ACL injury and reconstruction; however, the incidence of knee extension loss is not well defined. The aim of this review was to identify the incidence of loss of extension (LOE) following ACL rupture and reconstruction, explore the definitions of knee extension deficits reported and identify prognostic factors affecting LOE incidence.

METHODS

A systematic search was conducted in Medline, Cochrane Library and PEDro for studies in publication up to November 2021, with no restrictions on publication year. References were screened and assessed for inclusion using predetermined eligibility criteria. Randomised controlled trials (RCTs) that quantified knee angle, loss of extension or incidence of extension deficit were included for quality assessment and data extraction. Statistical summaries were generated and meta-analyses performed in two parts to examine: (i) the probability of a datapoint being zero incidence compared to a nonzero incidence and (ii) the relationship between the predictors and nonzero LOE incidence.

RESULTS

A sample of 15,494 studies were retrieved using the search criteria, with 53 studies meeting eligibility criteria. The pooled results from 4991 participants were included for analysis, with 4891 participants who had undergone ACLR. The proportion of included studies judged at an overall low risk of bias was small (7.8%). The observed group and study were the most important predictors for whether a datapoint reported an incidence of extension deficit. Time to follow-up (P < 0.001) and graft type (P = 0.02) were found to have a significant influence on nonzero LOE incidence (%). Covariate adjusted estimates of average LOE indicated 1 in 3 patients presenting with LOE at 12 month follow-up, reducing to 1 in 4 at 2 years.

CONCLUSIONS

This review examined the definitions for the measurement and interpretation of postoperative knee extension and established the trajectory of knee extension deficit after ACL injury and reconstruction. While factors associated with loss of extension were identified, the exact trajectory of knee extension deficits was difficult to infer due to discrepancies in measurement techniques and patient variation. On average, 1 in 3 patients may present with loss of extension of at least 3 degrees at 12-month follow-up, decreasing to 1 in 4 at 2 years. These results may be used by clinicians as an upper threshold for acceptable complication rates following ACLR. Future work should focus on LOE as a clinically relevant complication of ACL injury and treatment with appropriate attention to standardisation of definitions, measurements and better understanding of natural history.

PROSPERO REGISTRATION NUMBER

CRD42018092295.

LEVEL OF EVIDENCE

Level I.

Anterior cruciate ligament reconstruction results in better patient reported outcomes but has no advantage for activities of daily living or the subsequent development of osteoarthritis. A systematic review and meta-analysis

BACKGROUND

Surgical reconstruction of ACL injuries is a common strategy but superiority over conservative treatment has not been established. The aim was to perform a systematic review and meta-analysis comparing outcomes between operative and non-operative treatment of ACL injuries.

METHODS

Systematic review of Medline, Embase, Scopus, and Google Scholar, including all level 1-3 studies from 2000 to 2021. Patient reported outcome scores and objective measures for knee stability were included. Risk of bias was assessed using the Cochrane Collaboration's tools. GRADE was used to assess the quality of the body of evidence. Heterogeneity was assessed using χ2 and I² statistics.

RESULTS

Twelve studies were included in the analysis. All studies had a high risk of bias and were of low quality. The pooled estimates for IKDC (p = 0.040) favored surgical treatment. There were significant differences for activities of daily living (p = 0.0001) in favor of conservative treatment. There were significant differences for knee stability (p = 0.016) in favor of surgical treatment. The risk of osteoarthritis was not significantly different between the two treatment modalities (p = 0.219). Patients undergoing surgery had a 57% higher risk of osteoarthritis.

CONCLUSION

ACL reconstruction results in a significantly more stable knee with superior clinical and functional outcomes. However, these advantages over conservative treatment were not observed for routine activities of daily living, and subjective patient perceived outcomes favor nonsurgical treatment. Surgical treatment did not reduce the risk of later developing osteoarthritis. Regardless, due to low study quality and high risk of bias, these findings must be interpreted with caution.

Re-rupture rate and the post-surgical meniscal injury after anterior cruciate ligament reconstruction with the Press-Fit-Hybrid®-technique in comparison to the interference screw technique: a retrospective analysis of 200 patients with at least 3 years follow-up

BACKGROUND

There is currently no consensus regarding the preferred surgical procedure for the reconstruction of anterior cruciate ligament (ACL). The interference screw technique is widely used, but has been associated with a risk of graft damage. The Press-Fit-Hybrid®-technique is one of the alternatives for biological ACL-reconstruction with minimal implant requirements. The hypothesis of this retrospective analysis is, that the Press-Fit-Hybrid®-technique leads to better results with respect to re-rupture rate and secondary meniscal lesion than the interference-screw-technique.

METHODS

To compare the re-rupture rate of the interference-screw-technique (IF) used until 2015 with the currently used Press-Fit-Hybrid®-technique (PFH), the last 100 patients of the IF-group and the first 100 patients of the PFH-group were retrospectively analyzed. Primary outcomes were re-rupture rate, complications and secondary meniscal injury. Additionally, laxity, Lachman and Pivot-shift and range of motion were evaluated.

RESULTS

A mean follow-up of 4.2 and 5.3 years revealed 4% and 9% re-rupture rates and 1% and 2% complication rates in the PFH- and IF-group, respectively. In the PFH-group there were no re-ruptures in patients older than 23 years. Secondary meniscal injury post-surgery was 6% and 9% for the PFH and IF-group, respectively. Knee stability was similar in both groups. Range of motion was significantly better in the PFH-group, with 136° of flexion, 6 months after surgery.

CONCLUSION

For ACL-reconstruction the Press-Fit-Hybrid®-technique is an alternative new method. Low level of secondary meniscal lesions after surgery and high stability, is known to prevent later arthrosis of the knee. The encouraging observed trend of the reduction of the re-rupture rate in revision surgery and in young patients using the Press-Fit-Hybrid®-technique in comparison to the interference-screw-technique must be confirmed with further studies.

LEVEL OF EVIDENCE

Therapeutic Level III, retrospective cohort study.

An Investigation of the Nature of Fear within ACL-Injured Subjects When Exposed to Provocative Videos: A Concurrent Qualitative and Quantitative Study

Fear is a factor contributing to poor return to sport after an anterior cruciate (ACL) injury, however the identification and assessment of fear is challenging. To improve understanding of fear, this study qualitatively and quantitatively assessed responses to videos depicting threat to knee stability in people who had experienced an ACL injury. ACL-injured participants who had above average fear on the Tampa Scale of Kinesiophobia and were at least 1-year post-injury/surgery were eligible. Participants were shown four videos depicting sequentially increasing threat to their knee stability (running, cut-and-pivot, feigned knee injury during cut-and-pivot, series of traumatic knee injuries). Qualitative interviews explored participants feeling related to viewing the videos. Participants quantitatively self-rated fear and distress in response to each video. Seventeen participants were included in this study (71% female, with an average time since last ACL injury of 5 ½ years). Five themes were identified: (1) Evoked physiological responses, (2) Deeper contextualisation of the meaning of an ACL injury influencing bodily confidence, (3) Recall of psychological difficulties, (4) Negative implications of a re-injury, and (5) Change to athletic identity. Quantitatively, direct proportionality was noticed between threat level and reported fear and distress. Specifically, participants reported increasing levels of fear and distress as the videos progressed in threat level, with the largest increase seen between a cut-and-pivot movement to a feigned injury during a cut and pivot. The results support the notion that in addition to being a physical injury, an ACL injury has more complex neurophysiological, psychological, and social characteristics which should be considered in management. Using video exposure in the clinic may assist identification of underlying psychological barriers to recovery following an ACL injury, facilitating person-centred care.

ACL Reconstruction and Modified Lemaire Tenodesis Utilizing Common Suspensory Femoral Fixation

Persistent rotatory instability after anterior cruciate ligament (ACL) reconstruction has been well studied and recognized as the cause of unsatisfactory clinical results. Various anterolateral techniques have been described as an adjunct to the ACL reconstruction to improve clinical outcomes. Modified deep Lemaire lateral extra-articular tenodesis has been tested both biomechanically and clinically and proved an efficient solution in controlling tibia internal rotation, when performed in conjunction with ACL reconstruction. We describe a simple, versatile, effective, and reproducible technique of lateral extra-articular tenodesis, using common suspensory femoral fixation, with no additional cost and surgical risk.

Early ACLR and Risk and Timing of Secondary Meniscal Injury Compared With Delayed ACLR or Nonoperative Treatment: A Time-to-Event Analysis Using Machine Learning

BACKGROUND

Surgical and nonoperative management of anterior cruciate ligament (ACL) injuries seek to mitigate the risk of knee instability and secondary meniscal injury. However, the associated risk and timing of secondary meniscal tears have not been completely elucidated.

PURPOSE

To compare risk and timing of secondary meniscal injury between patients receiving nonoperative management, delayed ACL reconstruction (ACLR), and early ACLR using a machine learning survival analysis.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

A geographic database was used to identify and review records of patients with a diagnosis of ACL rupture between 1990 and 2016 with minimum 2-year follow-up. Patients undergoing ACLR were matched 1:1 with nonoperatively treated controls. Rate and time to secondary meniscal tear were compared using random survival forest algorithms; independent models were developed and internally validated for predicting injury-free duration in both cohorts. Performance was measured using out-of-bag c-statistic, calibration, and Brier score. Model interpretability was enhanced using global variable importance and partial dependence curves.

RESULTS

The study included 1369 patients who underwent ACLR and 294 patients who had nonoperative treatment. After matching, no significant differences in rates of secondary meniscal tear were found (P = .09); subgroup analysis revealed the shortest periods of meniscal survival in patients undergoing delayed ACLR. The random survival forest algorithm achieved excellent predictive performance for the ACLR cohort, with an out-of-bag c-statistic of 0.80 and a Brier score of 0.11. Significant variables for risk of meniscal tear for the ACLR cohort included time to return to sports or activity ≤350 days, time to surgery ≥50 days, age at injury ≤40 years, and high-impact or rotational landing sports, whereas those in the nonoperative cohort model included time to RTS ≤200 days, visual analog scale pain score >3 at consultation, hypermobility, and noncontact sports.

CONCLUSION

Delayed ACLR demonstrated the greatest long-term risk of meniscal injury compared with nonoperative treatment or early ACLR. Risk factors for decreased meniscal survival after ACLR included increased time to surgery, shorter time to return to sports or activity, older age at injury, and involvement in high-impact or rotational landing sports. Pending careful external validation, these models may be deployed in the clinical space to provide real-time insights and enhance decision making.

The development of long-term osteoarthritis following anterior cruciate ligament injury: reconstruction vs no reconstruction

PURPOSE

The high incidence of osteoarthritis (OA) in relatively young sportspeople following anterior cruciate ligament (ACL) reconstruction is concerning. Surgery is considered to reduce the development of OA compared to conservative management. This long-term study aimed to compare the incidence and severity of tibiofemoral OA (TFOA) and patellofemoral OA (PFOA) between reconstructed and non-reconstructed treatment groups and to determine which factors influence the development of OA.

MATERIALS AND METHODS

Fifty-six ACL-reconstructed and 45 conservatively treated patients from a cohort of 330 were followed for 11 years (mean) post-injury. Twenty-nine patients had received a bone-patellar tendon-bone (B-PT-B) graft, and 27 had received a hamstring (semitendinosus/gracilis) tendon (HT) graft. Assessment included objective and subjective stability, quadriceps and hamstring strength and radiology. Chi-square analyses compared OA between reconstructed and non-reconstructed groups and between B-PT-B, HT and non-surgical groups. Further analysis assessed the relationship between OA and age, time post-injury, meniscal injury/meniscectomy, quadriceps strength, hamstring strength, objective and subjective stability and sporting activity.

RESULTS

Forty-eight per cent reconstructed  and 53% non-reconstructed patients developed TFOA (p = 0.690). Thirty-six per cent reconstructed and 38% non-reconstructed patients developed PFOA (p = 0.831) with moderate PFOA occurring only in the non-reconstructed group. Close to significant differences (p = 0.075) were found comparing the severity of TFOA between groups with a higher incidence of moderate/severe OA in the non-reconstructed and B-PT-B groups. TFOA differed significantly between the B-PT-B and HT groups. The development of OA was related to age, time post-injury, meniscal injury/meniscectomy, quadriceps strength and subjective stability.

CONCLUSIONS

There were no significant differences in OA incidence between reconstructed and non-reconstructed groups but fewer patients developed TFOA following HT grafting compared to B-PT-B grafting and to non-surgical treatment. Quadriceps weakness and meniscal injuries/meniscectomy, both potentially modifiable, were strongly associated with the development of TF and PFOA.

Increased posterior tibial slope is an independent risk factor of anterior cruciate ligament reconstruction graft rupture irrespective of graft choice

INTRODUCTION

Anterior cruciate ligament (ACL) reconstruction failure remains a commonly seen complication despite advances in technique and graft options. Recently, several studies have shown that the inclination of the tibial plateau in the sagittal plane affects the stability of the knee joint. The purpose of this study was to determine if an increased posterior slope of the tibia is associated with failure of ACL reconstruction irrespective of the graft used.

METHODS

From June 2002 to August 2003, a total of 100 patients with a symptomatic ACL-deficient knee were randomised to receive either a hamstring autograft or posterior tibialis allograft. All allografts were from a single tissue bank, aseptically processed, and fresh-frozen without terminal irradiation. ACL graft failures requiring reoperation with a minimum of 10-year follow-up were identified via telephone survey. Lateral radiographs of the knee of all patients were reviewed, and the slope of the tibia was measured using a standardised technique. Two fellowship-trained orthopaedic sports medicine specialists, one board-certified general orthopaedic surgeon, and two fellowship-trained musculoskeletal radiologists measured the tibial slope in all patients.

RESULTS

At a minimum of 10-year follow-up, there were four (8.3%) autograft and 13 (26.5%) allograft failures that required revision reconstruction. The overall average tibial slope of the nonfailure cohort was 9.4°. The overall average tibial slope of the failure cohort was 11.9° (P ​= ​0.0002). The average slope of the allograft failures was 11.5°compared with an average slope of 9.6° in the nonfailures (P ​= ​0.01). The average slope of the autograft failures was 13.1° compared with 9.3° in the nonfailures (P ​= ​0.011). The mean difference in tibial slope measurements was 0.665 (95% confidence interval: 0.569-0.750). The interrater reliability, as measured by the intraclass correlation coefficient, for tibial slope was 0.898 (95% confidence interval: 0.859-0.928). The Cronbach α was 0.904.

CONCLUSION

In a prospective, randomised trial of ACL reconstructions using either autograft or allograft, failures were associated with a significantly increased slope of the tibia compared with the nonfailures at 10-year follow-up.

Risk factors of cartilage lesion after anterior cruciate ligament reconstruction

Anterior cruciate ligament injury is the most common sports injury in orthopaedics, which can adversely affect knee joint function and exercise of patients. Using arthroscopy to reconstruct the anterior cruciate ligament has become the first choice for treating anterior cruciate ligament rupture. However, different degrees of articular cartilage injury of the knee can be observed in patients after anterior cruciate ligament reconstruction. More importantly, the articular cartilage injury after anterior cruciate ligament reconstruction indicates that it will develop into osteoarthritis in the long term. It is of great significance to fully understand the factors that lead to the occurrence and development of cartilage injury. This article reviews the effects of surgical methods, meniscus status, different grafts, time from injury to surgical intervention, postoperative knee joint stability, postoperative rehabilitation, knee joint anatomical factors, and demographic characteristics of patients on articular cartilage degeneration after anterior cruciate ligament reconstruction. The present review provides insights into the anterior cruciate ligament reconstruction, which can be used to investigate new treatment strategies to delay and prevent the progress of osteoarthritis. At the same time, it provides a holistic understanding of the influence of multiple factors on cartilage lesions after anterior cruciate ligament reconstruction.

Adjustable-Loop Cortical Suspensory Fixation Results in Greater Tibial Tunnel Widening Compared to Interference Screw Fixation in Primary Anterior Cruciate Ligament Reconstruction

Background: Although the use of adjustable-loop suspensory fixation has increased in recent years, the influence of the shortcomings of suspensory fixation, such as the bungee-cord or windshield-wiper effects, on tunnel widening remains to be clarified. Hypothesis/Purpose: The purpose of this study was to compare adjustable-loop femoral cortical suspensory fixation and interference screw fixation in terms of tunnel widening and clinical outcomes after anterior cruciate ligament reconstruction (ACLR). We hypothesized that tunnel widening in the adjustable-loop femoral cortical suspensory fixation (AL) group would be comparable to that in the interference screw fixation (IF) group. Methods: This study evaluated patients who underwent primary ACLR at our institution between March 2015 and June 2019. The femoral and tibial tunnel diameters were measured using plain radiographs in the immediate postoperative period and 2 years after ACLR. Tunnel widening and clinical outcomes (Lysholm score, 2000 International Knee Documentation Committee subjective score, and Tegner activity level) were compared between the two groups. Results: There were 48 patients (mean age, 29.8 ± 12.0 years) in the AL group and 44 patients (mean age, 26.0 ± 9.5 years) in the IF group. Tunnel widening was significantly greater in the AL group than that in the IF group at the tibia anteroposterior (AP) middle (2.03 mm vs. 1.32 mm, p = 0.017), tibia AP distal (1.52 mm vs. 0.84 mm, p = 0.012), tibia lateral proximal (1.85 mm vs. 1.00 mm, p = 0.001), tibia lateral middle (2.36 mm vs. 1.03 mm, p < 0.001), and tibia lateral distal (2.34 mm vs. 0.85 mm, p < 0.001) levels. There were no significant differences between the two groups with respect to femoral tunnel widening and clinical outcomes. Conclusions: Tibial tunnel widening was significantly greater in the AL group than in the IF group at 2 years after primary ACLR. However, the clinical outcomes in the two groups were comparable at 2 years.

Primary surgery versus primary rehabilitation for treating anterior cruciate ligament injuries: a living systematic review and meta-analysis

OBJECTIVE

Compare the effectiveness of primarily surgical versus primarily rehabilitative management for anterior cruciate ligament (ACL) rupture.

DESIGN

Living systematic review and meta-analysis.

DATA SOURCES

Six databases, six trial registries and prior systematic reviews. Forward and backward citation tracking was employed.

ELIGIBILITY CRITERIA

Randomised controlled trials that compared primary reconstructive surgery and primary rehabilitative treatment with or without optional reconstructive surgery.

DATA SYNTHESIS

Bayesian random effects meta-analysis with empirical priors for the OR and standardised mean difference and 95% credible intervals (CrI), Cochrane RoB2, and the Grading of Recommendations Assessment, Development and Evaluation approach to judge the certainty of evidence.

RESULTS

Of 9514 records, 9 reports of three studies (320 participants in total) were included. No clinically important differences were observed at any follow-up for self-reported knee function (low to very low certainty of evidence). For radiological knee osteoarthritis, we found no effect at very low certainty of evidence in the long term (OR (95% CrI): 1.45 (0.30 to 5.17), two studies). Meniscal damage showed no effect at low certainty of evidence (OR: 0.85 (95% CI 0.45 to 1.62); one study) in the long term. No differences were observed between treatments for any other secondary outcome. Three ongoing randomised controlled trials were identified.

CONCLUSIONS

There is low to very low certainty of evidence that primary rehabilitation with optional surgical reconstruction results in similar outcome measures as early surgical reconstruction for ACL rupture. The findings challenge a historical paradigm that anatomic instability should be addressed with primary surgical stabilisation to provide optimal outcomes.

PROSPERO REGISTRATION NUMBER

CRD42021256537.

Post-traumatic knee osteoarthritis; the role of inflammation and hemarthrosis on disease progression

Knee injuries such as anterior cruciate ligament ruptures and meniscal injury are common and are most frequently sustained by young and active individuals. Knee injuries will lead to post-traumatic osteoarthritis (PTOA) in 25–50% of patients. Mechanical processes where historically believed to cause cartilage breakdown in PTOA patients. But there is increasing evidence suggesting a key role for inflammation in PTOA development. Inflammation in PTOA might be aggravated by hemarthrosis which frequently occurs in injured knees. Whereas mechanical symptoms (joint instability and locking of the knee) can be successfully treated by surgery, there still is an unmet need for anti-inflammatory therapies that prevent PTOA progression. In order to develop anti-inflammatory therapies for PTOA, more knowledge about the exact pathophysiological mechanisms and exact course of post-traumatic inflammation is needed to determine possible targets and timing of future therapies.

Comparison of Rotatory and Sagittal Laxity After Single-Bundle Versus Double-Bundle ACL Reconstruction: Outcomes at 7-Year Follow-up

Background:

Biomechanical studies have shown excellent anteroposterior and rotatory laxity control after double-bundle (DB) anterior cruciate ligament (ACL) reconstruction, but no clinical studies have compared midterm (>5-year) residual laxity between the DB and single-bundle (SB) techniques.

Purpose:

To clinically compare sagittal and rotatory laxities and residual sagittal laxity on the KT-1000 arthrometer between patients treated with an SB ACL reconstruction and those treated with a DB ACL reconstruction at the 7-year follow-up.

Study Design:

Cohort study; Level of evidence, 3.

Methods:

A total of 110 patients were included between January 2006 and December 2007. The patients were randomly assigned into 2 groups: those treated with SB ACL reconstruction (n = 63) and those treated with the DB technique (n = 47). All patients were then reviewed at a minimum of 7 years of follow-up; patients with ACL rerupture (n = 3 in the SB group and n = 2 in the DB group) were excluded from the postoperative comparative analysis. Residual anterior laxity (Lachman test), rotatory laxity (pivot-shift test), and sagittal laxity (KT-1000 arthrometer side-to-side difference) were measured and compared between the 2 groups.

Results:

The mean age at surgery was 23.0 ± 5.1 years for the DB group and 28.1 ± 7.0 years for the SB group, and the mean follow-up was 7.4 ± 0.8 years. No statistically significant differences were found between the 2 groups in terms of age, sex, preoperative laxity on KT-1000, preoperative Tegner score, or concomitant meniscal lesions. Residual postoperative laxity via Lachman testing (P < .01), pivot-shift testing (P = .042), and the KT-1000 arthrometer (P < .01) was statistically significantly in favor of DB reconstruction.

Conclusion:

DB ACL reconstruction allowed better control of anterior stability during the evaluation via the Lachman test and via objective measurement on the KT-1000, as well as rotatory stability at a minimum of 7 years of follow-up.

Returning Athletes to Sports Following Anterior Cruciate Ligament Tears

PURPOSE OF REVIEW

The purpose of this review is to discuss treatment options, rehabilitation protocols, return-to-play criteria, and expected outcomes after non-operative and operative treatment of anterior cruciate ligament (ACL) tears among an athletic population.

RECENT FINDINGS

Non-operative treatment may be a viable option for some athletes with an ACL tears but can be difficult to predict "copers," and those that resume to sports return at lower performance level and/or less intense activities. Most studies assessing function after ACL reconstruction demonstrate favorable outcomes using patient-reported outcome studies. However, return-to-play and graft re-rupture rates vary substantially based on patient characteristics and level and type of athletic activity. Grafts used to reconstruct ACL produce similar objective outcomes and favorable patient-reported outcomes but have variable re-rupture rates depending on study and differ largely on morbidity associated with graft harvest. Various treatment methods including non-operative and operative techniques have been demonstrated to be efficacious in returning athletes to athletic activity depending on patient age and level of activity. Adherence to fundamental rehabilitation principles and accepted return-to-play guidelines can optimize outcomes and limit re-injury to the injured or contralateral limb.

Optimal Graft Choice in Athletic Patients with Anterior Cruciate Ligament Injuries: Review and Clinical Insights

Anterior cruciate ligament (ACL) rupture is a common sporting-related knee injury with a potentially detrimental impact on the athlete’s career, yet there is no formal consensus on the optimal graft choice for reconstructing the ruptured ACL in this specific population. Options for reconstruction include autograft, allograft, and artificial grafts. However, each has associated failure risk and donor site morbidity. Our operational definition of the athlete is a skeletally mature individual participating in high level activity with the expectation to return to pre-injury level of activity. The athlete has unique injury characteristics, post-operative expectations, and graft demands that differ to the general population. Long-term outcomes are of particular importance given on-going mechanical demands on the reconstructed knee. Therefore, the purpose of this review is to consolidate current literature on the various ACL reconstruction graft options, with a focus on the optimal graft for returning the athlete to activity with the lowest rate of re-injury.

Association Between Anteromedial Portal Versus Tibial Tunnel Drilling and Meniscal Reoperation Risk Following Anterior Cruciate Ligament Reconstruction: A Cohort Study

BACKGROUND

Anterior cruciate ligament reconstruction (ACLR) provides functional stability to an injured knee. While multiple techniques can be used to drill the femoral tunnel during ACLR, a single technique has yet to be proven as clinically superior. One marker of postoperative functional stability is subsequent meniscal tears; a lower risk of subsequent meniscal surgery could be expected with improved knee stability.

PURPOSE

To determine if there is a meniscal protective effect when using an anteromedial portal (AMP) femoral tunnel drilling technique versus transtibial (TT) drilling.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

Data from Kaiser Permanente's ACLR registry were used to identify patients who had a primary isolated ACLR between 2009 and 2018; those with previous surgery in the index knee and meniscal pathology at the time of ACLR were excluded. The exposure of interest was TT (n = 2711) versus AMP (n = 5172) drilling. Multivariable Cox proportional hazard regression was used to evaluate the risk of a subsequent ipsilateral meniscal reoperation with adjustment for age, sex, femoral fixation, and graft choice. We observed a shift in surgeon practice from the TT to AMP over the study time frame; therefore, the relationship between technique and surgeon experience on meniscal reoperation was evaluated using an interaction term in the model.

RESULTS

At the 9-year follow-up, the crude cumulative meniscal reoperation probability for AMP procedures was 7.76%, while for TT it was 5.88%. After adjustment for covariates, we observed a higher risk for meniscal reoperation with AMP compared with TT (hazard ratio [HR], 1.53; 95% CI, 1.05-2.23). When stratifying by surgeon experience, this adverse association was observed for patients who had their procedure performed by surgeons with less AMP experience (no previous AMP ACLR: HR, 1.26; 95% CI, 0.84-1.91) while a protective association was observed for patients who had their procedure with more experienced surgeons (40 previous AMP ACLRs: HR, 0.34; 95% CI, 0.13-0.92).

CONCLUSION

Drilling the femoral tunnel via the AMP was associated with a higher risk of subsequent meniscal surgery compared with TT drilling. However, when AMP drilling was used by surgeons experienced with the technique, a meniscal protective effect was observed.

Differential regional perfusion of the human anterior cruciate ligament: quantitative magnetic resonance imaging assessment

Purpose

Surgical reconstruction is the current standard for ACL rupture treatment in active individuals. Recently, there is renewed interest in primary repair of proximal ACL tears. Despite this, ACL biology and healing potential are currently not well understood. Vascularity is paramount in ACL healing; however, previous ACL vascularity studies have been limited to qualitative histological and dissection-based techniques. The study objective was to use contrast-enhanced quantitative-MRI to compare relative perfusion of proximal, middle, and distal thirds of the in situ ACL. We hypothesized perfusion would be greatest in the proximal third.

Methods

Fourteen cadaveric knees were studied (8 females, 6 males), age 25–61 years. Superficial femoral, anterior tibial, and posterior tibial arteries were cannulated; without intraarticular dissection. Contrast-enhanced quantitative-MRI was performed using a previously established protocol. ACL regions corresponding to proximal, middle, and distal thirds were identified on sagittal-oblique pre-contrast images. Signal enhancement (normalized to tibial plateau cartilage) was quantified to represent regional perfusion as a percentage of total ACL perfusion. Comparative statistics were computed using repeated measures ANOVA, and pairwise comparisons performed using the Bonferroni method.

Results

Relative perfusion to proximal, middle, and distal ACL zones were 56.0% ±17.4%, 28.2% ±14.6%, and 15.8% ±16.3%, respectively (p = 0.002). Relative perfusion to the proximal third was significantly greater than middle (p = 0.007) and distal (p = 0.001). No statistically relevant difference in relative perfusion was found to middle and distal thirds (p = 0.281). Post-hoc subgroup analysis demonstrated greater proximal perfusion in males (66.9% ± 17.3%) than females (47.8% ± 13.0%), p = 0.036.

Conclusion

Using quantitative-MRI, in situ adult ACL demonstrated greatest relative perfusion to the proximal third, nearly 2 times greater than the middle third and 3 times greater than the distal third. Knowledge of differential ACL vascular supply is important for understanding pathogenesis of ACL injury and the process of biological healing following various forms of surgical treatment.

Biomechanical properties of common graft choices for anterior cruciate ligament reconstruction: A systematic review

BACKGROUND

This systematic review explores the differences in the intrinsic biomechanical properties of different graft sources used in anterior cruciate ligament (ACL) reconstruction as tested in a laboratory setting.

METHODS

Following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, two authors conducted a systematic review exploring the biomechanical properties of ACL graft sources (querying PubMed, Cochrane, and Embase databases). Using the keywords "anterior cruciate ligament graft," "biomechanics," and "biomechanical testing," relevant articles of any level of evidence were identified as eligible and included if they reported on the biomechanical properties of skeletally immature or mature ACL grafts solely and if the grafts were studied in vitro, in isolation, and under similar testing conditions. Studies were excluded if performed on both skeletally immature and mature or non-human grafts, or if the grafts were tested after fixation in a cadaveric knee. For each graft, failure load, stiffness, Young's modulus, maximum stress, and maximum strain were recorded.

FINDINGS

Twenty-six articles were included. Most studies reported equal or increased biomechanical failure load and stiffness of their tested bone-patellar tendon-bone, hamstring, quadriceps, peroneus longus, tibialis anterior and posterior, Achilles, tensor fascia lata, and iliotibial band grafts compared to the native ACL. All recorded biomechanical properties had similar values between graft types.

INTERPRETATION

Most grafts used for ACL reconstruction are biomechanically superior to the native ACL. Utilizing a proper graft, combined with a standard surgical technique and a rigorous rehabilitation before and after surgery, will improve outcomes of ACL reconstruction.

A larger side-to-side difference in anterior knee laxity increases the prevalence of medial and lateral meniscal injuries in patients with ACL injuries

PURPOSE

The objective of this study was to investigate factors that influence the prevalence of medial and lateral meniscal injuries at the time of anterior cruciate ligament (ACL) reconstruction in patients with ACL injuries.

METHODS

Patients with ACL injuries at 9 institutions were enrolled in this multicentre study. Age, sex, duration between injury and surgery, pivot shift test grade, anterior knee laxity determined using the Kneelax 3 arthrometer, and other variables were assessed by logistic regression analysis. Meniscal conditions were evaluated via arthroscopy.

RESULTS

In all, 830 patients were enrolled. The prevalence of medial and lateral meniscal tears was 32.0% (266 knees) and 26.5% (220 knees), respectively. Significant factors that influenced the prevalence of medial meniscal injuries were age [odds ratio (OR) 1.03; P = 0.000], side-to-side differences in instrumented anterior knee laxity before surgery (OR 1.12; P = 0.002), duration between injury and surgery (≥ 12 months) (OR 1.86; P = 0.023), and pivot shift test grade (OR 1.36; P = 0.014). Significant factors of lateral meniscal injury were side-to-side differences in anterior knee laxity before surgery (OR 1.12; P = 0.003) and the male sex (OR 1.50; P = 0.027).

CONCLUSION

Greater anterior knee laxity, age, a longer duration between injury and surgery, and a higher pivot shift test grade predicted medial meniscal injury. Greater anterior knee laxity and the male sex predicted lateral meniscal injury. In patients with ACL injuries, the importance of side-to-side differences in anterior knee laxity should be rediscovered from the viewpoint of meniscal conditions.

LEVEL OF EVIDENCE

Level III.

Cartilage oligomeric matrix protein responses to a mechanical stimulus associate with ambulatory loading in individuals with anterior cruciate ligament reconstruction

Mechanical factors have been implicated in the development of osteoarthritis after anterior cruciate ligament (ACL) reconstruction. This study tested for associations between ambulatory joint loading (total joint moment [TJM] and vertical ground reaction force [vGRF]) and changes in serum levels of cartilage oligomeric matrix protein (COMP) in response to a mechanical stimulus (30-min walk) in individuals with ACL reconstruction. Twenty-five subjects (mean age: 34.5 ± 9.8 years; 2.2 ± 0.2 years post-surgery) with primary unilateral ACL reconstruction underwent gait analysis for assessment of peak vGRF and TJM first (TJM1) and second (TJM2) peaks. Serum COMP concentrations were measured by enzyme-linked immunosorbent assay immediately before, 3.5 h, and 5.5 h after a 30-min walk. Pearson correlation coefficients and backward stepwise multiple linear regression analysis, with adjustments for age, sex, body mass index, and between-limb speed difference, assessed associations between changes in COMP and between-limb differences in joint loading parameters. Greater TJM1 (R = 0.542, p = 0.005), TJM2 (R = 0.460, p = 0.021), and vGRF (R = 0.577, p = 0.003) in the ACL-reconstructed limb as compared to the contralateral limb were associated with higher COMP values 3.5 h following the 30-min walk. Change in COMP at 5.5 h became a significant predictor of the between-limb difference in TJM1 and vGRF in multivariate analyses after accounting for the between-limb speed difference. These results demonstrate that higher TJM and vGRF in the ACLR limb as compared to the contralateral limb are associated with higher relative COMP levels 3.5 and 5.5 h after a 30-min walk. Future work should investigate the effect of therapies to alter joint loading on the biological response in individuals after ACL reconstruction.

Wavelet analysis reveals differential lower limb muscle activity patterns long after anterior cruciate ligament reconstruction

The purpose of this study was to test whether differences in muscle activity patterns between anterior cruciate ligament-reconstructed patients (ACLR) and healthy controls could be detected 10 to 15 years post-surgery using a machine learning classification approach. Eleven ACLR subjects and 12 healthy controls were recruited from an ongoing prospective randomized clinical trial. Surface electromyography (EMG) signals were recorded from gastrocnemius medialis and lateralis, tibialis anterior, vastus medialis, rectus femoris, biceps femoris, and semitendinosus muscles. Muscle activity was analyzed using wavelet analysis and examined within four sub-phases of the hop test, as well as an average of the task as a whole. K-nearest neighbor machine learning combined with a leave-one-out validation was used to classify the muscle activity patterns as either ACLR or Control. When muscle activity was averaged across the whole hop task, activity patterns for all muscles except the tibialis anterior were identified as being different between the study cohorts. ACLR patients demonstrated continuous muscle activities that spanned take-off, airborne, and landing hop phases versus healthy controls who displayed timed and regulated islets of muscle activities specific to each hop phase. The most striking features were 25-50% greater relative quadriceps intensity and approximately 66% diminished biceps femoris intensity in ACLR patients. The current findings are in contrast to previous work using conventional co-contraction and muscle activation onset EMG measures of the same dataset, underscoring the sensitivity and potential of the wavelet approach coupled with machine learning to reveal meaningful adaptation strategies in this at-risk population.

Long-term Return to Sports After Anterior Cruciate Ligament Injury: Reconstruction vs No Reconstruction-A Comparison of 2 Case Series

BACKGROUND

Reconstruction is considered to provide the best opportunity for return to sports (RTS) after anterior cruciate ligament (ACL) rupture. However, recent studies report that <50% of athletes return to preinjury sporting levels and that RTS rates at 1 year after injury are the same for athletes undergoing reconstruction and nonoperative management. Long-term studies are essential to confirm these findings and guide decisions regarding surgery.

PURPOSE

First, to compare long-term sports participation after ACL reconstruction and nonreconstruction and, second, to relate RTS level to strength and stability.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHOD

Patients with ACL deficiency (n = 101) who were referred for physical therapy at the time of diagnosis were followed long term: 56 were treated surgically 2.5 years (interquartile range [IQR], 1-4) after injury and 45 were treated nonoperatively. At long-term follow-up, the reconstructed group was at 9 years (IQR, 7-11) after injury and aged 33.3 ± 6.2 years (mean ± SD, 70% male; 61% meniscal injury), and the nonreconstructed group was at 11 years (IQR, 7-14) after injury and aged 38.7 ± 8.3 years (67% male; 58% meniscal injury). Measures of objective stability, subjective stability, and quadriceps/hamstring strength were compared between groups using independent-samples t tests. Current RTS level, scored on a 6-point scale, was compared between groups using chi-square tests. Spearman rho correlated RTS with outcome measures.

RESULTS

Of the total group of patients, 96% with reconstruction and 93% without continued to play sports. In the reconstructed and nonreconstructed groups, 4% and 7% did not RTS, and 8% and 17% returned to safe sports, respectively: 13% and 12% to running, 20% and 26% to sports involving limited twisting, 12% and 24% to recreational pivoting sports, and 43% and 14% to competitive pivoting sports. The only significant difference was in return to competitive pivoting sports (P = .003). Five patients with reconstruction ruptured the contralateral ACL, and 1 ruptured his graft. Most patients treated nonoperatively modified their sports participation. Their RTS levels correlated significantly with quadriceps strength (r = 0.65; P < .001), hamstring strength (r = 0.721; P < .001), and subjective stability (r = 0.405; P = .01).

CONCLUSION

Surgically treated patients returned to competitive pivoting sports at 3 times the rate of those managed nonoperatively, confirming that reconstruction provides the best opportunity for continued participation in competitive pivoting sports. Regardless of grouping, RTS correlated with modifiable factors, including strength and stability. Higher rates of subsequent injuries observed after reconstruction may result from increased participation in competitive pivoting sports.

Anterior Cruciate Ligament Injury and Knee Osteoarthritis: An Umbrella Systematic Review and Meta-analysis

OBJECTIVE

To conduct a systematic review of reviews to summarize the (1) risk for development and (2) prevalence of knee osteoarthritis (OA) after anterior cruciate ligament (ACL) injury and surgical treatment and (3) compare prevalence rates between surgical and nonsurgical treatment of ACL injury.

DATE SOURCES

Five electronic databases were searched using medical subject heading and text words up to February 2020 to identify English language reviews.

STUDY SELECTION

Studies were included if they were a systematic review or meta-analysis.

DATA EXTRACTION

Thirteen eligible reviews were included, and the main outcome extracted was knee OA prevalence or risk data and any meta-analysis results.

DATA SYNTHESIS

Results from reviews were combined with a summary meta-analysis based on odds ratios (ORs) or proportions. There was a near 7-fold and 8-fold increase in the odds for the development of knee OA post ACL injury [OR = 6.81 (5.70-8.13)] and ACL reconstruction [OR = 7.7, (6.05-9.79)]. Data were too heterogenous to specify a point estimate prevalence for OA after ACL injury, but OA prevalence was estimated at 36% (19.70-53.01) at near 10 years after reconstruction surgery. A significantly higher prevalence of OA was found for those who received surgical treatment at a minimum 10-year follow-up [OR = 1.40 (1.17-1.68)].

CONCLUSIONS

This study combines all data from previous systematic reviews into a single source to show that ACL injury markedly increases the risk for development of knee OA, which is likely to be present in the long term in approximately a third of patients who have reconstruction surgery. Surgical treatment does not reduce OA prevalence in the longer term compared with nonsurgical treatment.

Association of Quadriceps Strength Symmetry and Surgical Status With Clinical Osteoarthritis Five Years After Anterior Cruciate Ligament Rupture

OBJECTIVE

The objective of this study was to examine the association of quadriceps strength symmetry and surgical status (anterior cruciate ligament [ACL] reconstruction or nonoperative management) with early clinical knee osteoarthritis (OA) 5 years after ACL injury or reconstruction.

METHODS

In total, 204 of 300 athletes were analyzed 5 years after ACL injury or reconstruction. Quadriceps strength was measured and reported as a limb symmetry index. We identified participants with early clinical knee OA using the criteria that 2 of 4 Knee Injury and Osteoarthritis Outcome Score (KOOS) subscales score ≤85%. We calculated odds ratios (ORs) and 95% confidence intervals (95% CIs) using logistic regression and adjusted for age, sex, meniscal injury, and body mass index to examine the associations of quadriceps strength and surgical status with clinical knee OA.

RESULTS

In all, 21% of participants met the KOOS criteria for clinical knee OA. For every 1% increase in quadriceps limb symmetry index, there was a 4% lower odds of clinical OA (adjusted OR [OR_adj ] 0.96 [95% CI 0.93-0.99]) at 5 years. Surgical status was not associated with clinical knee OA (OR_adj 0.58 [95% CI 0.23-1.50]).

CONCLUSION

More symmetric quadriceps strength, but not surgical status, 5 years after ACL injury or reconstruction was associated with lower odds of clinical knee OA.

Social Determinants of Health Influence Access to Care and Outcomes in Patients Undergoing Anterior Cruciate Ligament Reconstruction: A Systematic Review

PURPOSE

To investigate the impact social determinants of health (SDOH) have on accessing orthopaedic treatment after an anterior cruciate ligament injury, as well as patient-reported and surgical outcomes after anterior cruciate ligament reconstruction (ACLR).

METHODS

A systematic search of the PubMed, MEDLINE, Epub Ahead of Print, Embase, and Web of Science databases was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines to identify studies that reported at least 1 SDOH and its effect on patient-reported outcomes or surgical outcomes after anterior cruciate ligament reconstruction. Our search identified 937 studies. After eliminating 273 duplicates, 2 authors screened 664 articles on the basis of title and abstract. After this initial screening, 76 studies were evaluated for data extraction. Studies were categorized based on the social determinant(s) of health reported.

RESULTS

Twenty-two articles published between 2002 and 2020 were included in this study, encompassing 15 retrospective cohort studies, 3 prospective cohort studies, 3 cross-sectional studies, and 1 case-control study from 9 journals across 3 countries. Of these articles, 9 investigated race/ethnicity, 8 investigated insurance status, 4 investigated income, 5 investigated education level, 2 investigated employment status, and 5 investigated socioeconomic status. Reported outcomes included time to treatment, concomitant knee injury, patient-reported outcome measurement scores, postoperative complications, need for additional surgery, and postoperative healthcare utilization.

CONCLUSIONS

Certain SDOH, including black race, Hispanic ethnicity, public health insurance, and lower socioeconomic status contribute to a delay in access to care, which may result in increased severity of concomitant knee injuries encountered at the time of anterior cruciate ligament reconstruction and inferior outcomes.

STUDY DESIGN

Level III, systematic review of level I-III evidence.

Patient-Reported Outcome, Return to Sport, and Revision Rates 7-9 Years After Anterior Cruciate Ligament Reconstruction: Results From a Cohort of 2042 Patients

BACKGROUND

Long-term patient-reported outcome measures (PROMs), rates of return to sport, and revision risk after anterior cruciate ligament (ACL) reconstruction (ACLR) are not well understood.

PURPOSE

To provide long-term follow-up of PROMs, return-to-sport rates, and revision rates after ACLR and to identify predictors for poor outcome.

STUDY DESIGN

Case-control study; Level of evidence, 3.

METHODS

A total of 2042 patients were included in an institutional ACL registry (2009-2013) and longitudinally followed. PROMs were completed preoperatively and at all follow-up time points. Questions regarding return to sport and knee stability were completed at final follow-up. Predictors for poor outcome on the International Knee Documentation Committee (IKDC) score were estimated in a regression model incorporating risk factors such as patient characteristics, graft choice, and concomitant injuries. Revision rates and risk of subsequent non-ACL surgeries were calculated.

RESULTS

Autografts were used in 76% of the patients (patellar tendon, 62%; hamstring grafts, 38%). Allografts were used in 24% of patients. The questionnaires were returned by 1045 (51.2%) patients at a mean of 7.2 years (range, 5.0-9.8 years) after surgery. Improvements in IKDC score of >30 points were sustained for all patient categories. The strongest predictor for lesser improvement in IKDC score was a cartilage lesion >2 cm2 identified during surgery. Male sex and college education completion were associated with improved IKDC scores. Meniscal lesions did not predict change) in the IKDC score. A total of 69% of patients had returned to sport after 8.1 years (range, 6.7-9.8 years). The main reason for not returning to sport was fear of reinjury. The revision rate was 7.2% after 9 years (range, 8-11 years), 13% of patients needed subsequent ipsilateral non-ACL surgery, and 6% underwent contralateral ACLR. The absence of a meniscal tear, younger age, and male sex were predictors for revision. Graft choice did not predict PROM results or revision risk.

CONCLUSION

Improvements in IKDC scores were sustained 7 years after ACLR. The strongest predictor for poor outcome was a cartilage lesion >2 cm2. Patients can expect a 70% return-to-sport rate and an 87% chance of their knee feeling stable during daily and athletic activities after 8 years. Young male patients have better PROM scores but a higher risk of revision. There is a 26% chance of subsequent knee surgery within 9 years, including a revision rate of 7%, subsequent non-ACL surgery to the operated knee in 13%, and a 6% chance of contralateral ACLR.

Current trends in the anterior cruciate ligament part II: evaluation, surgical technique, prevention, and rehabilitation

Clinical evaluation and management of anterior cruciate ligament (ACL) injury is one of the most widely researched topics in orthopedic sports medicine, giving providers ample data on which to base their practices. The ACL is also the most commonly treated knee ligament. This study reports on current topics and research in clinical management of ACL injury, starting with evaluation, operative versus nonoperative management, and considerations in unique populations. Discussion of graft selection and associated procedures follows. Areas of uncertainty, rehabilitation, and prevention are the final topics before a reflection on the current state of ACL research and clinical management of ACL injury. Level of evidence V.

Anterior Cruciate Ligament Reconstruction versus Nonoperative Treatment: Better Function and Less Secondary Meniscectomies But No Difference in Knee Osteoarthritis-A Meta-Analysis

OBJECTIVES

The impact of anterior cruciate ligament (ACL) reconstruction on knee osteoarthritis (OA) is still unclear. The aim of the current meta-analysis was to compare surgical treatment versus nonoperative management of ACL tears to assess the impact of these approaches on knee OA development at a 5 and 10 years of follow-up.

DESIGN

A meta-analysis was performed after a systematic literature search (May 2021) was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) guidelines. Both randomized and nonrandomized comparative studies with more than 5 years of follow-up were selected. Influence of the treatment was assessed in terms of knee OA development, subjective and objective clinical results, activity level, and risk of further surgeries. Risk of bias and quality of evidence were assessed following the Cochrane guidelines.

RESULTS

Twelve studies matched the inclusion criteria, for a total of 1,004 patients. Level of evidence was rated low to very low. No difference was documented in terms of knee OA development, Tegner score, subjective International Knee Documentation Committee (IKDC), and Lysholm scores. A significant difference favoring the surgical treatment in comparison with a nonsurgical approach was observed in terms of objective IKDC score (P = 0.03) and risk of secondary meniscectomy (P < 0.0001). The level of evidence was considered very low for subjective IKDC, low for knee OA development, objective IKDC, number of secondary meniscectomies, and Lysholm score, and moderate for post-op Tegner score.

CONCLUSIONS

The meta-analysis did not support an advantage of ACL reconstruction in terms of OA prevention in comparison with a nonoperative treatment. Moreover, no differences were reported for subjective results and activity level at 5 and 10 years of follow-up. On the contrary, patients who underwent surgical treatment of their ACL tear presented important clinical findings in terms of better objective knee function and a lower rate of secondary meniscectomies when compared with conservatively managed patents.Protocol Registration: CRD420191156483 (PROSPERO).

Low rate of return to pre-injury level of sports after multi-ligament knee injury - Functional outcomes after MLKI

BACKGROUND

Multi-ligament knee injury (MLKI) is a rare but severe injury with potential devastating complications. The primary goal of this study was to investigate return to sports and work after MLKI. Secondary outcomes were patient reported outcome measures (PROMs), treatment, time between trauma, diagnosis and treatment, and neurovascular damage.

METHOD

A database search was performed to identify all patients with MLKI in our hospital (2010-2017). Pre-defined variables were collected from patient files and questionnaires. Multiple regression analysis was used to study the relationship between different variables and PROMs.

RESULTS

31 patients were included. The overall return to sports rate after a MLKI was 88.5%, but only 23.1% returned to their pre-injury level. 83.3% of the patients were able to return to work. Multiple regression analyses led to a significant prediction model for pain during rest (F(7,16) = 2.808, p = 0.041, R² = 0.355). Within this model, a higher age was a significant predictor for higher pain scores (p = 0.002). Age was also a significant (negative) predictor within the non-significant models for IKDC (p = 0.004) and Lysholm (p = 0.024). A delay between trauma and diagnosis of more than three months was seen in 32.3% of the patients.

CONCLUSIONS

This study showed a relatively high overall return to sports and work after MLKI, but less than a quarter returned to their pre-injury level of sports. An important finding was the substantial number of patients with a delay between trauma and diagnosis. This study contributes to more awareness and knowledge about MLKI among physicians, which is essential to reduce these delays.

Anatomic characteristics of the knee influence the risk of suffering an isolated meniscal injury and the risk factors differ between women and men

PURPOSE

To analyse the relationship between multiple anatomic characteristics of the knee (tibia and femur) and isolated meniscal injury in women and men.

METHODS

Forty-seven patients with isolated medial meniscal injuries, 62 patients with isolated lateral meniscal injuries, and 70 control subjects were included. Medial posterior tibial slope (MTS), lateral posterior tibial slope (LTS), medial tibial plateau depth (MTD), coronal tibial slope (CTS), femoral notch width (NW), femoral condylar width (FCW), intercondylar notch depth (ND), femoral notch width index (NWI), intercondylar notch shape index (NSI), and cruciate ligaments tensity (CLT) were measured from magnetic resonance images. Anatomic characteristics differing between groups were compared, and risk factors for isolated meniscal injury were identified by multivariate forward stepwise logistic regression for men and women separately.

RESULTS

Risk factors for an isolated medial meniscal injury were a steeper MTS and a lowered MTD in men, and a steeper MTS and an increased NWI in women. Risk factors for isolated lateral meniscal injury were a steeper LTS and an increased NW in men, and a steeper LTS and a lowered ND in women. Risk factors for both medial and lateral meniscal injuries were a higher CTS, an increased NWI, and a looser CLT in men, and a higher CTS, an increased NSI, and a looser CLT in women.

CONCLUSION

The anatomic characteristics of the tibial plateau, femur, and cruciate ligaments influence the risk of suffering isolated meniscal injury, and the risk factors differ between men and women. This study provides a reference for developing identification criteria for those at risk of isolated meniscal injury.

LEVEL OF EVIDENCE

III.

Patellar cartilage increase following ACL reconstruction with and without meniscal pathology: a two-year prospective MRI morphological study

Background

Anterior cruciate ligament reconstruction (ACLR) together with concomitant meniscal injury are risk factors for the development of tibiofemoral (TF) osteoarthritis (OA), but the potential effect on the patellofemoral (PF) joint is unclear. The aim of this study was to: (i) investigate change in patellar cartilage morphology in individuals 2.5 to 4.5 years after ACLR with or without concomitant meniscal pathology and in healthy controls, and (ii) examine the association between baseline patellar cartilage defects and patellar cartilage volume change.

Methods

Thirty two isolated ACLR participants, 25 ACLR participants with combined meniscal pathology and nine healthy controls underwent knee magnetic resonance imaging (MRI) with 2-year intervals (baseline = 2.5 years post-ACLR). Patellar cartilage volume and cartilage defects were assessed from MRI using validated methods.

Results

Both ACLR groups showed patellar cartilage volume increased over 2 years (p < 0.05), and isolated ACLR group had greater annual percentage cartilage volume increase compared with controls (mean difference 3.6, 95% confidence interval (CI) 1.0, 6.3%, p = 0.008) and combined ACLR group (mean difference 2.2, 95% CI 0.2, 4.2%, p = 0.028). Patellar cartilage defects regressed in the isolated ACLR group over 2 years (p = 0.02; Z = − 2.33; r = 0.3). Baseline patellar cartilage defect score was positively associated with annual percentage cartilage volume increase (Regression coefficient B = 0.014; 95% CI 0.001, 0.027; p = 0.03) in the pooled ACLR participants.

Conclusions

Hypertrophic response was evident in the patellar cartilage of ACLR participants with and without meniscal pathology. Surprisingly, the increase in patellar cartilage volume was more pronounced in those with isolated ACLR. Although cartilage defects stabilised in the majority of ACLR participants, the severity of patellar cartilage defects at baseline influenced the magnitude of the cartilage hypertrophic response over the subsequent ~ 2 years.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12891-021-04794-5.

Treatment of Concomitant ACL and MCL Injuries: Spontaneous Healing of Complete ACL and MCL Tears

The mainstay of treatment for anterior cruciate ligament (ACL) tear is considered to be surgery, especially when associated with medial collateral ligament (MCL) tears. We aimed to evaluate our hypothesis that some patients with concomitant ACL and MCL tears may develop spontaneous healing without surgical intervention. This study was conducted during 2013 to 2017. A total of 707 patient referred with combined ACL and MCL injuries. Patients were divided into three groups according to type of ACL and MCL management as follows: (1) group 1 as those who only had ACL reconstruction without any surgical treatment of MCL; (2) group 2 as those who had ACL reconstruction and MCL surgery (reconstruction, reefing, or both); (3) group 3 as those who showed spontaneous healing of ACL and MCL. Overall, 206 and 129 patients entered groups 1 and 2, respectively. Overall, 15 patients showed spontaneous healing of ACL and entered group 3. Skiing and soccer were the most common causes of injury within the third group, followed by traffic accidents (35.7%, 35.7% and 21.4%, respectively). All these were noncontact injuries within this groups. In group 3 only three patients had concomitant meniscal injury. Mean healing time for patient with spontaneous healing was 8.66 ± 3.41 months. All patients showed ACL tears at the proximal part of its attachment. During follow-up, all pivot shift, Lachman and MCL tests were either negative or one plus. All these individuals returned to previous physical activity. Among the total number of patients with skiing injuries presenting with concomitant ACL/MCL injuries (27 patients), five patients (18.5%) showed spontaneous healing. Valgus and external rotation injuries with dominancy of valgus force, apart from a MCL tear, may lead to proximal tear of ACL as well, and the inflammation from the torn MCL can potentiate and stimulate the healing process of ACL; thus, patient with this mechanism of injury is better followed before surgical intervention is planned as spontaneous healing may occur.

[Consequences of anterior cruciate ligament rupture: a systematic umbrella review]

INTRODUCTION

 The treatment of an anterior cruciate ligament rupture is still controversial. In particular, this applies to the question of conservative versus surgical treatment. The answer to this question is often based on consequential damage such as the development of posttraumatic osteoarthritis, secondary damage to the meniscus or cartilage, and participation in sports. If there are significant differences in these parameters between the individual treatment options, the results will be of great importance for the development of evidence-based treatment pathways. Therefore, the aim of this work was to evaluate the development of knee osteoarthritis after rupture of the anterior cruciate ligament and the corresponding treatment (conservative or surgical).

MATERIAL AND METHODS

 To answer the above question, a systematic literature search was conducted in Medline via Pubmed, the Cochrane Library and in CINAHL. Only systematic reviews with a minimum follow-up period of 10 years were included. The search was conducted in January 2020 and updated in January 2021. Investigated cohorts included patients with a rupture of the anterior cruciate ligament who had undergone either conservative or surgical treatment. Osteoarthritis was diagnosed either radiologically (recognized scores) or clinically (pain and impaired function). Appropriate reviews were qualitatively evaluated using the AMSTAR-2 questionnaire.

RESULTS

 The literature research initially identified n = 42 reviews from which 14 reviews were included. After full-text review and qualitative evaluation, only n = 2 systematic reviews remained for evaluation. The results of both papers show imprecise data with a high variability. However, it can be assumed with high probability that the development of osteoarthritis of the knee is increased after a rupture of the anterior cruciate ligament. There is no evidence that the incidence of joint degeneration may be reduced by reconstruction of the anterior cruciate ligament, nor is there a difference when comparing conservative and surgical treatment directly.

CONCLUSION

 Patients with an anterior cruciate ligament rupture are likely to be at a greater risk of developing progressive joint degeneration. A protective effect of cruciate ligament surgery has not been found in the evaluated studies. A general argument in favour of cruciate ligament surgery aiming to achieve a protective effect on hyaline articular cartilage seems obsolete based on the results and should therefore not be used in patient education in the future.

Low Rates of Radiographic Knee Osteoarthritis 5 Years After ACL Reconstruction or Rehabilitation Alone: The Delaware-Oslo ACL Cohort Study

BACKGROUND

Patients and clinicians often struggle to choose the optimal management strategy for posttraumatic knee osteoarthritis (OA) after an anterior cruciate ligament (ACL) injury. An evaluation of radiographic outcomes after a decision-making and treatment algorithm applicable in clinical practice can help to inform future recommendations and treatment choices.

PURPOSE

To describe and compare 5-year radiographic outcomes and knee pain in individuals who had gone through our decision-making and treatment algorithm and chosen (1) early (<6 months) ACL reconstruction (ACLR) with pre- and postoperative rehabilitation, (2) delayed (>6 months) ACLR with pre- and postoperative rehabilitation, or (3) progressive rehabilitation alone.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

We included 276 patients with unilateral ACL injury from a prospective cohort study. Patients chose management using a shared decision-making process and treatment algorithm, and 5-year postoperative radiographs of the index and contralateral knees were assessed using the Kellgren and Lawrence (K&L) classification and minimum joint space width measurements. We defined radiographic tibiofemoral OA as K&L grade ≥2 and knee pain as a Knee injury and Osteoarthritis Outcome Score for Pain ≤72. To further explore early radiographic changes, we included alternative cutoffs for radiographic knee OA using K&L grade ≥2/osteophyte (definite osteophyte without joint space narrowing) and K&L grade ≥1.

RESULTS

At 5 years, 64% had undergone early ACLR; 11%, delayed ACLR; and 25%, progressive rehabilitation alone. Radiographic examination was attended by 187 patients (68%). Six percent of the cohort had radiographic tibiofemoral OA (K&L grade ≥2) in the index knee; 4%, in the contralateral knee. Using the alternative cutoffs at K&L grade ≥2/osteophyte and K&L grade ≥1, the corresponding numbers were 20% and 33% in the index knee and 18% and 29% in the contralateral knee. Six percent had a painful index knee. There were no statistically significant differences in any radiographic outcomes or knee pain among the 3 management groups.

CONCLUSION

There were no statistically significant differences in any 5-year radiographic outcomes or knee pain among the 3 management groups. Very few of the patients who participated in our decision-making and treatment algorithm had knee OA or knee pain at 5 years.

Dynamic Radiostereometry Evaluation of 2 Different Anterior Cruciate Ligament Reconstruction Techniques During a Single-Leg Squat

Background:

Lateral extra-articular tenodesis in the context of anterior cruciate ligament (ACL) reconstruction (ACLR) is performed to better control anterolateral knee instability in patients with high-grade preoperative pivot shift. However, some authors believe these procedures may cause lateral compartment overconstraint, affecting knee motion in daily life.

Purpose/Hypothesis:

The primary aim of the present study was to identify kinematic differences during the execution of an activity under weightbearing conditions between knees having undergone ACLR using anatomic single-bundle (SB) versus single-bundle plus lateral plasty (SBLP) techniques. The secondary aim was to compare the postoperative kinematic data with those from the same knees before ACLR and from the healthy contralateral knees in order to investigate if ACLR was able to restore physiologic knee biomechanics during squat execution. The hypotheses were that (1) the SBLP technique would allow a better restoration of internal-external (IE) knee rotation than would SB and (2) regardless of the technique, ACLR would not fully restore physiologic knee biomechanics.

Study Design:

Randomized controlled trial; Level of evidence, 2.

Methods:

In total, 32 patients (42 knees) were included in the study. Patients were asked to perform a single-leg squat before surgery (ACL-injured group, n = 32; healthy contralateral group, n = 10) and at minimum 18-month follow-up after ACLR (SB group, n = 9; SBLP group, n = 18). Knee motion was determined using a validated model-based tracking process that matched patient-specific magnetic resonance imaging bone models to dynamic biplane radiographic images under the principles of roentgen stereophotogrammetric analysis. Data processing was performed using specific software. The authors compared IE and varus-valgus rotations and anterior-posterior and medial-lateral translations among the groups.

Results:

The mean follow-up period was 21.7 ± 4.5 months. No kinematic differences were found between the SB and SBLP groups (P > .05). A more medial tibial position (P < .05) of the ACL-injured group was reported during the entire motor task and persisted after ACLR in both the SB and the SBLP groups. Differences in IE and varus-valgus rotations were found between the ACL-injured and healthy groups.

Conclusion:

There were no relevant kinematic differences between SBLP and anatomic SB ACLR during the execution of a single-leg squat. Regardless of the surgical technique, ACLR failed in restoring knee biomechanics.

Registration:

NCT02323386 (ClinicalTrials.gov identifier).

Hybrid Remnant-Sparing Anterior Cruciate Ligament Repair-Reconstruction

In anterior cruciate ligament (ACL) reconstruction, the remnant ACL is often debrided in an effort to improve visualization of patient anatomy and reduce surgical difficulty. However, retention of the tibial remnant of a torn ACL theoretically portends several advantages. These include preservation of knee proprioception and mechanoreceptors, an enhanced biological environment for healing, and accelerated revascularization and ligamentization of the graft. Despite these advantages, it is not a widely adopted practice and the optimal technique is still subject to debate. The purpose of this technical note is to describe our preferred technique for performing hybrid ACL reconstruction with remnant incorporation.