Procedural intervention for arthrofibrosis after ACL reconstruction: trends over two decades

Complications in Anterior Cruciate Ligament Surgery and How to Avoid Them

Complications following anterior cruciate ligament (ACL) reconstruction can be detrimental to a patient's recovery and limit their ability to successfully return to sport. Arthrofibrosis, graft failure, and infection are a few examples of complications that can arise. Therefore, it is important for surgeons to recognize that each step during perioperative surgical decision making can impact patients' risk for such complications. The purpose of this paper is to discuss common complications following ACL reconstruction and how surgeons can avoid or reduce the risk of complications.

Seven percent of primary anterior crucial ligament reconstruction patients have arthroscopic resection of cyclops lesions within 2 years: A cohort study of 2556 patients

PURPOSE

After anterior cruciate ligament reconstruction (ACL-R), a localised scar tissue called cyclops lesion may develop anterior to the graft causing knee extension deficits, pain, oedema, clicking and reduced knee function. This study determined the incidence of arthroscopic resection of a cyclops lesion within 2 years after ACL-R and investigated the associations of patient characteristics and surgical techniques with the need for arthroscopic resection of a cyclops lesion.

METHODS

This study included patients who underwent primary ACL-R with adult surgical technique from 2005 to 2019 at Aarhus University Hospital, Denmark. The cohort was identified in a national registry. To identify patients who had resected a cyclops lesion within the first 2 years after ACL-R, patients' surgical records were reviewed.

RESULTS

In 2005-2019, 2556 patients underwent primary ACL-R; 176 developed cyclops lesions that were resected within 2 years, equivalent to an incidence of 6.9% (95% confidence interval [CI]: 5.9-7.9). When stratified by the femoral drilling technique used, this incidence was 8.9% (95% CI: 7.7-10.3) with the anteromedial technique and 1.9% (95% CI: 1.0-3.1) with the transtibial technique. The incidence was 8.5% (95% CI: 6.8-10.3) in women and 5.7% (95% CI: 4.6-7.1) in men. Age, graft choice and the presence of cartilage or meniscal lesions did not affect the incidence.

CONCLUSION

The overall incidence of a cyclops lesion removal within 2 years post-ACL-R was 6.9%. This was five times higher with the anteromedial femoral drilling technique than with the transtibial technique. Women had a 47% higher incidence of cyclops lesion removal than men. This is relevant for the surgeon when planning an ACL-R.

LEVEL OF EVIDENCE

Level II.

Influence of female sex and double-quadruple semitendinosus-gracilis graft on the incidence of postoperative symptomatic cyclops lesions after ACL reconstruction

PURPOSE

Risk factors for the development of symptomatic cyclops lesion after anterior cruciate ligament reconstruction (ACLR) surgery are not entirely identified yet. This study aimed to investigate whether the choice of hamstring graft (semitendinosus-gracilis; STG vs. semitendinosus; ST) affects the risk of developing a symptomatic cyclops lesion after ACLR.

METHODS

This retrospective cohort study included 1416 patients receiving either an ST graft (n = 1209) or an STG graft (n = 207) ACLR with a follow-up of at least 2 years. A persisting extension limitation was clinically determined, and cyclops lesions were confirmed by magnetic resonance imaging (MRI) and second-look arthroscopy. Graft-specific incidence of cyclops lesions was examined with χ2 test and combined with the factors number of graft bundles, graft diameter and sex evaluated with a binominal logistic regression model.

RESULTS

In total, 46 patients developed symptomatic cyclops lesions (3.2%), with 36 having ACLR with an ST graft (3.0%) and 10 with an STG graft (4.8%) (n.s). The mean time from ACLR to the second-look arthroscopy for cyclops removal was 1.1 ± 0.6 years. Female patients were 2.5 times more likely to develop a cyclops lesion than male patients. Patients with an STG graft and larger graft diameters did not have a higher risk of developing cyclops lesions. Patients who received an STG graft with both tendons folded four times (double-quadruple) had significantly higher risk of developing a cyclops compared with all other numbers of graft bundles combined (8.3%, respectively 3.0%; p = 0.014).

CONCLUSION

This study could not prove an increased risk of developing a symptomatic cyclops lesion for patients with an STG graft compared with an ST graft used for ACLR. However, patients with a double-quadruple ACLR had a higher percentage of cyclops lesions compared with all other numbers of graft bundles. Female sex was associated with an increased risk of developing cyclops lesions.

LEVEL OF EVIDENCE

Level III.

Risk Factors for the Development of Arthrofibrosis After Anterior Cruciate Ligament Reconstruction in Children and Adolescents

BACKGROUND

Arthrofibrosis is a fibrotic joint disorder resulting in restricted joint motion and pain. Risk factors associated with the development of postoperative arthrofibrosis include female sex, type of graft, and quicker time to reconstruction. These patients have typically benefitted from manipulation under anesthesia or arthroscopic lysis of adhesions. The purpose of this study was to retrospectively review the rate of arthrofibrosis in children and adolescents who previously underwent anterior cruciate ligament (ACL) reconstruction.

MATERIALS AND METHODS

This was a retrospective chart review examining patients 18 years or younger who underwent ACL reconstruction between 2013 and 2023. Data collected included age, body mass index, reconstruction technique, concomitant meniscal or ligamentous pathology, and need for revision surgery for arthroscopic lysis of adhesions vs manipulation under anesthesia.

RESULTS

A total of 461 patients 18 years or younger who underwent ACL reconstruction were included in this study. Eighteen (3.90%) patients required reoperation for the development of arthrofibrosis. Skeletally immature patients were found to have a statistically significant lower rate of arthrofibrosis compared with skeletally mature patients (0% vs 4.80%; P=.0184). Patients with a higher weight and body mass index had an increased rate of arthrofibrosis (P=.0485 and P=.0410, respectively). Graft type did not have a significant impact on arthrofibrosis rates. There were no significant findings in terms of concomitant injuries and rate of arthrofibrosis.

CONCLUSION

Arthrofibrosis developed in 3.90% of patients after ACL reconstruction. Skeletal immaturity may be protective against the development of arthrofibrosis. No association was found between graft type or concomitant knee pathology and arthrofibrosis. [Orthopedics. 202x;4x(x):xx-xx.].

Female Sex, Older Age, Earlier Surgery, Anticoagulant Use, and Meniscal Repair Are Associated With Increased Risk of Manipulation Under Anesthesia or Lysis of Adhesions for Arthrofibrosis After Anterior Cruciate Ligament Reconstruction: A Systematic Review

PURPOSE

To determine what patient or surgical factors are associated with an increased risk of arthrofibrosis requiring manipulation under anesthesia (MUA) or lysis of adhesions (LOA) after anterior cruciate ligament reconstruction (ACLR).

METHODS

A systematic review was performed in adherence to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Cochrane, Embase, and Medline databases were searched for studies published through February 2023. Inclusion criteria were studies that identified risk factors for MUA and/or LOA after ACLR. Studies investigating arthrofibrosis after multiligamentous knee injuries or ACL repair were excluded.

RESULTS

Eleven studies including a total of 333,876 ACLRs with 4,842 subsequent MUA or LOA (1.45%) were analyzed. Increasing age was associated with an increased risk in 3 studies (P < .001, P < .05, P < .01) but was found to have no association another two. Other factors that were identified by multiple studies as risk factors for MUA/LOA were female sex (4 studies), earlier surgery (5 studies), use of anticoagulants other than aspirin (2 studies), and concomitant meniscal repair (4 studies).

CONCLUSIONS

In total, 1.45% of the patients who underwent ACLR and were included in this systematic review had to undergo a subsequent MUA/LOA to treat arthrofibrosis. Female sex, older age, earlier surgery, use of anticoagulants other than aspirin, and concomitant meniscal repair were associated with increased risk of MUA/LOA. The modifiable risks, including use of anticoagulants and time between injury and surgery, can be considered when making treatment decisions.

LEVEL OF EVIDENCE

Level IV, systematic review of Level III-IV studies.

Efficacy of ADIPOR1 and ADIPOR2 peptide-agonist AdipoRon in preventing contracture in a rabbit model of arthrofibrosis

AdipoRon is an adiponectin receptor 1, 2 (ADIPOR1 and ADIPOR2) agonist with potential antifibrotic effects. Whether AdipoRon can mitigate joint stiffness in a rabbit model of arthrofibrosis is unknown. We examined the efficacy of intravenous (IV) AdipoRon at mitigating contracture in a rabbit model of knee arthrofibrosis. Fifty-six female New Zealand White rabbits were divided into three dosing groups: vehicle (dimethyl sulfoxide, DMSO), 2.5 mg/kg AdipoRon, and 5 mg/kg AdipoRon. AdipoRon, in DMSO, was administered IV preoperatively and for 5 days postoperatively (30 rabbits, Aim 1). AdipoRon was again dosed similarly after Kirschner wire (K-wire) removal at 8 weeks (26 rabbits; Aim 2). The primary outcome of joint passive extension angle (PEA,°) was measured at 8, 10, 12, 16, and 24 weeks following index surgery. At 24 weeks, rabbits were euthanized and limbs were harvested to measure posterior capsular stiffness (N cm/°). In Aim 1, the 5 mg/kg treated rabbits had a significant increase in PEA when compared to controls at 16-week (p < 0.05). In Aim 2, the 5 mg/kg treated rabbits had a significant increase in PEA when compared to controls at 10-week (p < 0.05). In both aims, no significant differences were observed at later time points. Capsular stiffness was no different in any group. We are the first to report the efficacy of IV AdipoRon in a rabbit model of arthrofibrosis. We identified a significant dose-dependent decrease in joint PEA at early time points; however, no differences were observed between groups at later time points. Clinical Significance: The present investigation provided the first assessment of AdipoRon's efficacy in mitigating knee stiffness in the current gold standard rabbit model of arthrofibrosis. Results of this investigation provided further evidence as to the potential role of AdipoRon as a preventative for arthrofibrosis in large mammals.

Manipulation Under Anesthesia and Lysis of Adhesions Are the Most Commonly Reported Treatments for Arthrofibrosis of the Knee After Arthroscopy or Anterior Cruciate Ligament Reconstruction in Both Pediatric and Adult Patients

Purpose

To systematically review the literature and provide a detailed summary of the current treatments and outcomes for arthrofibrosis following knee arthroscopy and anterior cruciate ligament reconstruction (ACLR) and to compare the treatment strategies in pediatric and adult populations.

Methods

A systematic review was performed in March 2022 using PubMed, EMBASE, and Cochrane Library Databases per Preferred Reporting Items for Systematic Reviews and Meta-Analyses. Search terms consisted of variations of the following: ("arthrofibrosis" OR "stiffness" OR "stiff" OR "complications") AND ("arthroscopy" OR "arthroscop" OR "ACL" OR "anterior cruciate") AND ("treat" OR "care" OR "management" AND "knee"). The inclusion criteria were studies that were written in English, were published since 2000, and that reported outcomes of knee arthroscopy or ACLR for treatment of arthrofibrosis of the knee. The study quality was assessed, and data about the patients and treatments were recorded. Treatments were compared between pediatric and adult patients.

Results

A total of 1,208 articles were identified in the initial search, 42 (3.48%) of which met eligibility criteria, involving treatment regimens for arthrofibrosis following knee arthroscopy or ACLR. Of the 42 studies included, 29 (69.0%) were reported data for adults and 13 (31.0%) reported data for pediatric patients. Thirty-nine studies (92.8%) discussed manipulation under anesthesia and/or lysis of adhesions (LOA) as treatment for arthrofibrosis of the knee, whereas 2 (4.8%) described the use of medications.

Conclusions

Within orthopaedic sports medicine literature, there is variability in the reported treatment options for arthrofibrosis of the knee. Most studies identified manipulation under anesthesia and/or LOA as the treatment among both adult and pediatric patients. Other variants include notchplasty, open posterior arthrolysis, total graft resection, removal of hardware with LOA, dynamic splinting, casting in extension, bracing, and medications.

Level of Evidence

Level IV, systematic review of Level I-IV studies.

Risk factors for reoperation for arthrofibrosis following primary anterior cruciate ligament reconstruction

PURPOSE

The purpose of this study is to identify the rate and risk factors for a reoperation for arthrofibrosis following primary anterior cruciate ligament (ACL) reconstruction.

METHODS

Prospective data recorded in the New Zealand ACL Registry were cross-referenced with data from the Accident Compensation Corporation (ACC). Primary ACL reconstructions performed between April 2014 and May 2021 were analysed. The ACC database was used to identify patients who underwent a reoperation for a diagnosis of arthrofibrosis. Multivariable survival analysis was performed to compute adjusted hazard ratios (aHR) and 95% confidence intervals.

RESULTS

A total of 12,296 primary ACL reconstructions were analysed, of which 230 underwent a reoperation for arthrofibrosis (1.9%) at a mean follow-up of 3.6 years. A higher risk of arthrofibrosis was observed in females (aHR = 1.76, p = 0.001), patients with a history of previous knee surgery (aHR = 1.82, p = 0.04) and when a transtibial drilling technique was used (aHR = 1.53, p = 0.03). ACL reconstruction >6 months after injury had the lowest rate of arthrofibrosis (1.3%, aHR = 0.45, p = 0.01). There was no difference in risk between early surgery within 6 weeks versus delayed surgery between 6 weeks and 6 months after injury (2.9% versus 2.1%, aHR = 0.78, not significant).

CONCLUSION

Female sex, previous knee surgery and a transtibial drilling technique increased the risk of reoperation for arthrofibrosis. Early surgery within 6 weeks of injury was not associated with an increased risk when compared with surgery between 6 weeks and 6 months after injury.

LEVEL OF EVIDENCE

Level III.

AdipoRon reduces TGFβ1-mediated collagen deposition in vitro and alleviates knee stiffness in vivo

Arthrofibrosis, which causes joint motion restrictions, is a common complication following total knee arthroplasty (TKA). Key features associated with arthrofibrosis include myofibroblast activation, knee stiffness, and excessive scar tissue formation. We previously demonstrated that adiponectin levels are suppressed within the knee tissues of patients affected by arthrofibrosis and showed that AdipoRon, an adiponectin receptor agonist, exhibited anti-fibrotic properties in human mesenchymal stem cells. In this study, the therapeutic potential of AdipoRon was evaluated on TGFβ1-mediated myofibroblast differentiation of primary human knee fibroblasts and in a mouse model of knee stiffness. Picrosirius red staining revealed that AdipoRon reduced TGFβ1-induced collagen deposition in primary knee fibroblasts derived from patients undergoing primary TKA and revision TKA for arthrofibrosis. AdipoRon also reduced mRNA and protein levels of ACTA2, a key myofibroblast marker. RNA-seq analysis corroborated the anti-myofibrogenic effects of AdipoRon. In our knee stiffness mouse model, 6 weeks of knee immobilization, to induce a knee contracture, in conjunction with daily vehicle (DMSO) or AdipoRon (1, 5, and 25 mg/kg) via intraperitoneal injections were well tolerated based on animal behavior and weight measurements. Biomechanical testing demonstrated that passive extension angles (PEAs) of experimental knees were similar between vehicle and AdipoRon treatment groups in mice evaluated immediately following immobilization. Interestingly, relative to vehicle-treated mice, 5 mg/kg AdipoRon therapy improved the PEA of the experimental knees in mice that underwent 4 weeks of knee remobilization following the immobilization and therapy. Together, these studies revealed that AdipoRon may be an effective therapeutic modality for arthrofibrosis.

Low Preoperative Brief Resilience Scale Scores Are Associated With Inferior Preoperative and Short-Term Postoperative Patient Outcomes Following Primary Autograft Anterior Cruciate Ligament Reconstruction

Purpose

To assess preoperative Brief Resilience Scale (BRS) scores as they relate to postoperative patient outcomes following primary autograft anterior cruciate ligament reconstruction (ACLR).

Methods

All patients who underwent primary autograft ACLR from 2016 to 2021 and had a patient-reported follow-up of 1 year and a clinical follow-up of 6 months were included in final data analysis. Patients completed validated PROMs pre- and postoperatively. All patients were objectively assessed with range of motion (ROM) and KT-1000 arthrometer testing. Return to sport (RTS) data were obtained for all applicable patients. Patients were divided into 3 groups based on ± ½ the standard deviation for the mean preoperative BRS score.

Results

In total, 170 patients who underwent primary autograft ACLR with a mean age of 20.1 years (range, 13-57 years) and a mean final follow-up time of 2.9 years (range, 1.0-5.8 years) were included in the final analysis. The mean preoperative BRS scores for the high-resilience (HR, n = 67), average-resilience (AR, n = 42), and low-resilience (LR, n = 61) groups were 28.1 (95% CI, 27.8-28.9), 24.5 (95% CI, 24.3-24.6), and 21.1 (95% CI, 20.5-21.7), respectively (P < .001). The HR group demonstrated significantly higher preoperative and postoperative patient-reported outcome measures (PROMs) compared to the AR and LR groups, with more differences seen with the LR group. The HR group demonstrated better knee extension in postoperative month 3 compared to the LR group (0.6° [95% CI, -1.2° to 0.1°] vs -2.3° [95% CI, -3.3° to -1.3°], P = .006). The HR group demonstrated a faster RTS time compared to the LR group (6.4 months [95% CI, 6.1-6.7] vs 7.6 months [95% CI, 7.1-8.1], P = .002). No differences were seen in RTS rate, knee flexion, or KT-1000 arthrometer measurements between the 3 groups.

Conclusions

Low preoperative BRS scores were associated with inferior PROMs preoperatively and in the short-term postoperative period compared to those with higher preoperative BRS scores. Additionally, patients with lower preoperative BRS scores demonstrated a higher degree of knee extension loss 3 months postoperatively as well as a slower RTS.

Level of Evidence

Level III, retrospective cohort study.

Arthrofibrosis risk factors after anterior cruciate ligament reconstruction

Introduction

Knee arthrofibrosis is a disabling complication after anterior cruciate ligament reconstruction (ACLr). Different risk factors have been studied but are still controversial because of a diagnosis made only during reoperations for the treatment of the stiffness, which underestimates the occurrence rate. We aimed to confirm risk factors of arthrofibrosis after ACLr in case of clinically made diagnoses.

Methods

Ninety-two athletes with clinically diagnosed arthrofibrosis, complicating a primary ACLr, were compared to 482 athletes with ACLr without any complications. Usually considered risk factors were studied: age under 18, female, Body Mass Index (BMI ≥ 25), high sport level, time from ACL injury to ACLr < 1 month, Bone-Patella-Tendon-Bone surgical procedure (BPTB), meniscal repair, and intensive rehabilitation. Binary logistic regression was carried out to confirm or refute these risk factors.

Results

Female, time from ACL injury to ACLr < 1 month, BPTB procedure, meniscal repair, and BMI ≥ 25 were not confirmed as risk factors. Previous competitive sport level assessed by Tegner score was the only risk factor identified, OR: 3.56 (95%IC: 2.20-5.75; p = 0.0001). Age < 18, OR: 0.40 (95%IC: 0.19-0.84; p = 0.015) and inpatient rehabilitation program, OR: 0.28 (95%IC: 0.17-0.47; p = 0.0001), were protective factors.

Discussion

Competitive athletes are at risk of arthrofibrosis after ACLr and should benefit from protective inpatient rehabilitation program.

Risk Factors for Symptomatic Cyclops Lesion Formation after Anterior Cruciate Ligament Reconstruction

Objective  To evaluate the incidence of symptomatic cyclops lesions requiring surgical treatment after anterior cruciate ligament (ACL) reconstruction and to establish possible intraoperative risk factors related to it. Methods  Three hundred and eighty-nine patients aged between 18 and 50 years who underwent primary ACL reconstruction were retrospectively evaluated. Patients were divided into groups according to the presence or absence of symptomatic cyclops lesions, and their characteristics were compared. Patients with associated lesions that required additional surgical procedures (except anterolateral extra-articular procedures) were not included. The rate of symptomatic cyclops lesions was recorded and the following parameters were evaluated: age, gender, time from injury to surgery, graft type and diameter, femoral tunnel perforation technique, fixation type, presence of knee hyperextension, preservation of the ACL remnant, associated anterolateral extra-articular procedure, associated meniscal injury and participation in sports. Results  389 patients were evaluated and 26 (6.7%) patients developed cyclops. The patients with and without cyclops lesions did not differ in age, time from injury to surgery, graft type or diameter, surgical technique, femoral fixation method, presence of knee hyperextension, remnant preservation and associated meniscal injury. The group with cyclops lesion had a higher proportion of females (10 (38.4%) vs 68 (18.7%); OR = 2.7; p  = 0.015), higher proportion of extra-articular reconstruction (18 (11.8%) vs 8 (3.4%); OR = 3.8; p  = 0.001) and higher proportion of sports practice (23 (8.6%) vs 3 (2.5%); OR = 3.6; p  = 0.026). Conclusion  In our series, 6.7% of the patients required arthroscopic removal of cyclops lesions. Female gender, associated extra-articular reconstruction and sports practice were factors related to this lesion. Remnant preservation had no relationship with cyclops lesion formation.

Arthroscopic Lysis of Adhesions for Arthrofibrosis After Anterior Cruciate Ligament Reconstruction

BACKGROUND

Arthrofibrosis (AF) after anterior cruciate ligament reconstruction (ACLR) remains a challenge. There is a paucity of data on arthroscopic interventions for AF after ACLR.

PURPOSE

To (1) describe the patient, injury, and surgical characteristics and patient-reported outcomes (PROs) of those requiring an arthroscopic intervention for loss of motion after ACLR and (2) compare outcomes between patients undergoing an early intervention (within 3 months) versus those undergoing a late intervention (after 3 months).

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

Patients with a history of ACLR and a subsequent operative procedure for postoperative AF at a single institution between 2000 and 2018 were retrospectively identified. Arthroscopic interventions included lysis of adhesions, capsular release with or without manipulation under anesthesia, and excision of cyclops lesions. Patients were excluded if they had a knee dislocation or multiple-ligament injury, a periarticular fracture, or less than 2-year follow-up from the arthroscopic intervention. PROs including the Tegner activity score, visual analog scale pain score, and International Knee Documentation Committee score as well as knee range of motion (ROM) were recorded.

RESULTS

A total of 40 patients were included with a mean age of 27.2 years (range, 11.0-63.8 years) at surgery and a mean follow-up of 10.0 years (range, 2.9-20.7 years). The mean preoperative flexion and extension were 102° (range, 40°-150°) and 8° (range, 0°-25°), respectively. The mean postoperative flexion and extension were 131° (range, 110° to 150°) and 0° (range, -10° to 5°), respectively. After the arthroscopic intervention, the mean ROM improved from 94° (range, 40°-140°) preoperatively to 131° (range, 107°-152°) at final follow-up (P < .001), and the visual analog scale pain score improved from 3.0 preoperatively to 1.2 postoperatively (P = .001). Overall, 13 patients (32.5%) underwent an intervention within 3 months and 27 (67.5%) after 3 months. The early intervention group had a higher postoperative International Knee Documentation Committee score compared with the late intervention group (86.8 vs 71.7, respectively; P = .035).

CONCLUSION

An arthroscopic intervention for AF after ACLR successfully improved knee ROM and pain. Patients who underwent either early or late surgery obtained satisfactory motion and function, although improved PROs were observed when the intervention occurred within 3 months of the primary procedure.

Manipulation Under Anesthesia and/or Lysis of Adhesions After Anterior Cruciate Ligament Reconstruction in Female Basketball Players: Does Race Play a Role?

BACKGROUND

Arthrofibrosis can limit function and return to sport after anterior cruciate ligament (ACL) reconstruction. Previously reported risk factors for developing arthrofibrosis after ACL reconstruction include female sex, age <18 years, time from injury to surgery <28 days, concomitant meniscal repair, prolonged immobilization, and genetic factors. There is a lack of evidence regarding whether race plays a significant role.

HYPOTHESIS

The risk of undergoing manipulation under anesthesia (MUA) and/or lysis of adhesions (LOA) after primary ACL reconstruction with bone-patellar tendon-bone (BTB) autograft in female basketball players is higher in African American players than in White players.

STUDY DESIGN

Case-control study; Level of evidence, 3.

METHODS

Using a computerized relational database, the authors identified competitive female basketball players who underwent primary ACL reconstruction with BTB autograft by the senior author over a 13-year period. Data previously entered from examinations and surgical findings were reviewed retrospectively. Univariate statistics and multivariable logistic regression were used to assess the relationship between undergoing subsequent MUA and/or LOA and study predictors.

RESULTS

A total of 186 knees (114 African American knees and 72 White knees) met inclusion criteria. The overall rate of MUA and/or LOA was 8.6%. Thirteen African American knees (11.4%) and 3 White knees (4.2%) underwent MUA and/or LOA for treatment of arthrofibrosis. No study predictor was found to have a statistically significant relationship with the rate of MUA and/or LOA on univariate analysis. However, when controlling for body mass index and previously described risk factors (age <18 years, time from injury to surgery ≤28 days, and concomitant meniscal repair) in the logistic regression model, the authors found that MUA and/or LOA was more likely in African American (odds ratio, 4.01 [95% CI, 1.01-15.92]; P = .049) than in White female players and in patients who underwent ACL reconstruction within 28 days of injury (odds ratio, 4.01 [95% CI, 1.18-13.57]; P = .026) compared with those with surgery delayed beyond 28 days.

CONCLUSION

In female basketball players, the present study found a statistically significantly increased risk for undergoing MUA and/or LOA after primary ACL reconstruction with BTB autograft in African American females compared with White females and in patients who underwent ACL reconstruction within 28 days of injury.

Uncommon, foreign-body induced knee arthrofibrosis in a pediatric patient

Arthrofibrosis is defined as an excessive fibrotic tissue response within a joint leading to a painful loss of motion. This pathological scar formation process with dysregulated, inordinate extracellular matrix formation, especially collagen, may occur in any joints, although is frequently localized in the knee. Different etiologies have been described and most of them are related to trauma, infection or recent surgical procedure. Although arthrofibrosis affects people of all ages, it is unusual in pediatric population. We present a case report of an uncommon, foreign body induced knee arthrofibrosis in a 14-year old boy. We also review the current literature regarding diagnostic procedures and treatment rationale for arthrofibrosis of the knee.

Risk Factors and Outcomes for Preoperative Stiffness Requiring Intervention Before Anterior Cruciate Ligament Reconstruction

Background

To date, there is a scarcity of literature related to the incidence of prolonged stiffness after an anterior cruciate ligament (ACL) tear that requires manipulation under anesthesia/lysis of adhesions (MUA/LOA) in the preoperative period before ACL reconstruction (ACLR) and how preoperative stiffness influences outcomes after ACLR.

Hypothesis

Preoperative stiffness requiring MUA/LOA would increase the risk for postoperative stiffness, postoperative complications, and the need for subsequent procedures after ACLR.

Study Design

Cohort study; Level of evidence, 3.

Methods

The PearlDiver Research Program was used to identify patients who sustained an ACL tear and underwent ACLR using their respective International Classification of Diseases, 9th or 10th Revision, and Current Procedure Terminology (CPT) codes. Within this group, patients with preoperative stiffness were identified using the CPT codes for MUA or LOA. Significant risk factors for preoperative stiffness were identified through univariate and multivariate logistic regression analyses. Outcomes after ACLR were analyzed between patients with and without preoperative stiffness using multivariate logistic regression, controlling for age, sex, and Elixhauser Comorbidity Index.

Results

Between 2008 and 2018, 187,071 patients who underwent ACLR were identified. Of these patients, 241 (0.13%) underwent MUA/LOA before ACLR. Patients with preoperative stiffness began preoperative physical therapy significantly later than patients without stiffness (P = .0478) and had a delay in time to ACLR (P = .0003). Univariate logistic regression demonstrated that female sex, older age, anxiety/depression, obesity, and anticoagulation use were significant risk factors for preoperative stiffness (P < .05 for all). After multivariate regression, anticoagulation use was the only independent risk factor deemed significant (odds ratio, 6.69 [95% CI, 4.01-10.51]; P < .001). Patients with preoperative stiffness were at an increased risk of experiencing postoperative stiffness, deep vein thrombosis, pulmonary embolism, surgical-site infection, and septic knee arthritis after ACLR (P < .05 for all).

Conclusion

Although the risk of preoperative stiffness requiring an MUA/LOA before ACLR is low, the study findings indicated that patients with preoperative stiffness were at increased risk for postoperative complications compared with patients with no stiffness before ACLR.

Editorial Commentary: Risk Factors of Cyclops Syndrome in Quadriceps Autograft Anterior Cruciate Ligament Reconstruction: More Helpful Data in Weighing Graft Choice

Arthrofibrosis after anterior cruciate ligament (ACL) reconstruction can be a devastating complication with risk factors and causes not well established. Cyclops syndrome is a subtype involving localized scar anterior to the graft, which is typically treated with arthroscopic debridement. ACL quadriceps autograft is a newly popular graft option for which clinical data continue to develop. However, recent research shows possible increased risk of arthrofibrosis with quadriceps autograft. Possible causes include inability to achieve active terminal knee extension after extensor mechanism graft harvesting; patient characteristics, including female sex, and social, psychological, musculoskeletal, and hormonal differences; larger graft diameter; concomitant meniscus repair; exposed collagen fibers of the graft abrading the fat pad or tibial tunnel or intercondylar notch; smaller notch size; intra-articular cytokine; and biomechanical stiffness of the graft.

Intervention of Refractory Arthrofibrosis After Anterior Cruciate Ligament Reconstruction: A Case Report

OBJECTIVES

Although nonsurgical and surgical management of knee arthrofibrosis has been reported in the literature, there is little information on the effect of procedural treatment modalities of refractory arthrofibrosis on clinical outcomes. The purpose of this case report is to describe the intervention of refractory knee arthrofibrosis after anterior cruciate ligament reconstruction and investigate long-term clinical outcomes after procedural intervention.

METHODS

A 27-year-old male presented with decreased range of motion (ROM), patellar mobility, strength, and knee joint function following anterior cruciate ligament reconstruction of his left knee. After failed conservative management, the patient underwent manipulation under anesthesia (MUA) to release scar tissue. Following MUA, the emphasis of comprehensive physiotherapy was on decreasing inflammation, relieving pain, and maintaining patellar mobility while increasing knee joint ROM and strength. Knee ROM, patellofemoral motion, gait, and quadriceps recruitment were measured 3, 6, 12, and 24 months after MUA.

RESULTS

At 2-year follow-up after MUA, the patient continued to present with decreased ROM and quadriceps strength compared to the contralateral knee, but had returned to a running program and reported knee joint dysfunction no longer interfered with his daily activities.

CONCLUSIONS

This case report demonstrates signs and symptoms that could indicate knee arthrofibrosis and introduces procedural intervention for refractory arthrofibrosis after anterior cruciate ligament reconstruction.

Effect of Trainee Level on Surgical Time and Postoperative Complications of Anterior Cruciate Ligament Reconstruction

PURPOSE

The objective of this study was to investigate the association between trainee level and surgical time and postoperative complications of anterior cruciate ligament reconstruction (ACLR).

METHODS

A retrospective chart review of patients who underwent ACLR at an academic orthopaedic ambulatory surgery center collected demographic and clinical information, including the number of trainees present and trainee level. Unadjusted and adjusted regression analyses assessed the association between trainee number and level with surgical time (time from skin incision to closure) and postoperative complications.

RESULTS

Of 799 patients in this study operated on by one of five academic sports surgeons, 87% had at least one trainee involved. The average surgical time overall was 93 ± 21 minutes and by trainee level was 99.7 (junior resident), 88.5 (senior residents), 96.6 (fellows), and 95.6 (no trainees). Trainee level was significantly associated with surgical time (P = 0.0008), with increased surgical time in cases involving fellows (0.0011). Fifteen complications (1.9%) were observed within 90 days of surgery. No notable risk factors of postoperative complications were identified.

CONCLUSION

Resident trainee level does not have a notable effect on surgical time or postoperative complications for ACLR at an ambulatory surgery center, although cases involving fellows had longer surgical times. Trainee level was not associated with risk of postoperative complications.

Is arthroscopic assisted double tibial tunnel fixation a good option for tibial eminentia fractures?

Tibial eminentia fractures are avulsion fractures of the anterior cruciate ligament caused with additional injuries like meniscus tears or ligamentous injuries. Arthroscopic assisted internal fixation has become a preferred technique with the development of arthroscopic techniques. We aimed to present our results for arthroscopic assisted double tibial tunnel fixation in patients with displaced eminentia fracture. Twenty patients who were operated on for eminentia fracture between January 2010 and May 2014 were included in this study. All fractures were type II according to Meyers's classification. Eminentia was reduced with two nonabsorbable sutures through the ACL. Two tibial tunnels were created over the medial proximal tibia with a 2.4 mm cannulated drill. The two suture ends taken out of the 2 tibial tunnels were connected on the bone bridge between the tunnels. Patients were evaluated with Lysholm score, Tegner score, IKDC score and examined for clinical and radiological evidence of bony union. Quadriceps exercises were started on the third day. The patients were followed up with a locked knee brace in extension for 3 weeks after surgery and later patients were encouraged to mobilize as pain allowed. The preoperative Lysholm score was 75 ±3.3 and the postoperative Lysholm score was 94.5 ±3. Tegner score was 3.52±1.02 preoperatively and 6.84±1.099 postoperatively. International Knee Documentation Committee(IKDC) score was abnormal in all of the 20 patients preoperatively but normal postoperatively. The postoperative scores of the patients were statistically significant when compared with preoperative activity scores(p<0,0001). Tibial eminentia fractures may lead to pain, knee instability, malunion, laxity, or extension deficit. The technique we have described together with early rehabilitation may give good clinical results.

Delay of Timing of Anterior Cruciate Ligament Reconstruction Is Associated With Lower Risk of Arthrofibrosis Requiring Intervention

PURPOSE

To conduct 2 separate stratum-specific likelihood ratio analyses in patients younger than 40 year of age (<40 years) and those aged 40 and older (40+ years) at time of anterior cruciate ligament (ACL) reconstruction to define data-driven strata between ACL tear and primary isolated ACL reconstruction in which the risk of arthrofibrosis, using manipulation under anesthesia and arthroscopic lysis of adhesions as surrogates, is significantly different.

METHODS

A retrospective cohort analysis was conducted using the PearlDiver Database. Patients who underwent ACL reconstruction were identified using the Current Procedure Terminology code 29888. Patients were stratified to those aged younger than 40 (<40) and those 40 and older (40+) at time of ACL reconstruction. The incidence of 2-year arthrofibrosis was calculated for weekly intervals from initial ACL injury to reconstruction. Stratum specific likelihood ratio analysis was conducted to determine data-driven intervals from initial ACL tear to reconstruction that optimize differences in 2-year arthrofibrosis. Following the identification of these intervals for both those <40 and 40+, multivariable analysis was conducted.

RESULTS

For those <40, stratum-specific likelihood ratio analysis identified only 2 data-driven timing strata: 0-5 and 6-26 weeks. For those 40+, stratum-specific likelihood ratio analysis also only identified 2 data-driven strata: 0-9 and 10-26 weeks. A delay in ACL reconstruction from initial injury by at least 6 weeks in patients younger than 40 and at least 10 weeks in patients older than 40 years is associated with a 65% and 35% reduction of 2-year manipulation under anesthesia and arthroscopic lysis of adhesions, respectively.

CONCLUSIONS

Our analysis showed a delay in ACLR of at least 6 weeks in patients younger than 40 years to be associated with a 65% reduction in the risk of surgical intervention for arthrofibrosis and a delay of at least 10 weeks in patients 40 years and older to be associated with only a 35% reduction in the risk of surgical intervention for arthrofibrosis. The authors propose this difference in reduction to be multifactorial and potentially associated with mechanism of injury, activity level, and preoperative factors such as amount of physical therapy, rather than solely timing.

LEVEL OF EVIDENCE

III, retrospective comparative prognostic study.

An analysis of the incidence, risk factors, and timing of development of cyclops lesions after anterior cruciate ligament reconstruction

BACKGROUND

Cyclops lesions are a known complication following anterior cruciate ligament reconstruction (ACLR) with a described incidence between 1.9% to 10.9%. The objective of this study was to identify the incidence, timing, and variables that correlated with development of a cyclops lesion, and if objective functional testing differed between patients with and without cyclops lesions.

METHODS

313 consecutive patients who underwent ACLR and participated in Lower-Extremity Assessment Protocol (LEAP) testing at a single, academic institution were analyzed. Retrospective chart review was performed to identify patient demographic factors, medical comorbidities, and potential peri-operative risk factors. Postoperative functional outcome metrics and patient reported outcomes were collected per the institution's LEAP testing protocol. Binary logistic regression was utilized to identify risk factors for cyclops lesions. Objective functional outcomes and patient reported outcomes were compared between patients with and without cyclops lesions.

RESULTS

23/313 (7.35%) patients developed a cyclops lesion following ACLR, of which 17 (73.91%) were found to be symptomatic. Concomitant meniscal repair correlated with an increased likelihood of developing a cyclops lesion (p = 0.040); no other risk factors significantly differed between cohorts. There were no clinically relevant extension deficits or differences in objective functional performance measures at six months post-operatively between study cohorts.

CONCLUSIONS

Concomitant meniscal repair may be associated with the development of cyclops lesions due to restrictive postoperative range of motion protocols; however no other pre- or intra-operative factors demonstrated significant correlation. Presence of a cyclops lesion should be considered with late loss of knee extension after ACLR.

IFN-α-2b Reduces Postoperative Arthrofibrosis in Rats by Inhibiting Fibroblast Proliferation and Migration through STAT1/p21 Signaling Pathway

Objective

To investigate the effect of IFN-α-2b in preventing postoperative arthrofibrosis in rats, its antiproliferation effect on fibroblasts in vitro, and its molecular mechanism.

Methods

The rat model of arthrofibrosis was established and treated with different concentrations of drugs. Knee specimens were collected for histological and immunohistochemical staining to observe the effect of IFN-α-2b on arthrofibrosis in rats. The biological information was further mined according to the database data, and the possible regulatory mechanism of IFN-α-2b on fibroblasts was analyzed. The inhibitory effect of IFN-α-2b on fibroblast proliferation and migration in vitro was detected by cell counting kit-8 (CCK-8), immunofluorescence analysis, cell cycle test, EdU assay, wound healing test, and Transwell method, and the analysis results were verified by Western blotting method.

Results

The test results of rat knee joint specimens showed that IFN-α-2b significantly inhibited the degree of fibrosis after knee joint surgery, the number of fibroblasts in the operation area was less than that of the control group, and the expression of collagen and proliferation-related proteins decreased. In vitro experimental results show that IFN-α-2b can inhibit the proliferation and migration of fibroblasts. According to the results of database analysis, it is suggested that the STAT1/P21 pathway may be involved, and it has been verified and confirmed by Western blotting and other related methods.

Conclusion

IFN-α-2b can reduce surgery-induced arthrofibrosis by inhibiting fibroblast proliferation and migration, which may be related to the regulation of STAT1/p21 signaling pathway.

Localized Anterior Arthrofibrosis After Soft-Tissue Quadriceps Tendon Anterior Cruciate Ligament Reconstruction Is More Common in Patients Who Are Female, Undergo Meniscal Repair, and Have Grafts of Larger Diameter

PURPOSE

To determine factors associated with localized anterior arthrofibrosis (cyclops lesion), such as graft size, warranting early reoperation for lysis of adhesions after anterior cruciate ligament reconstruction (ACLR) with all-soft tissue quadriceps tendon (ASTQT) autograft.

METHODS

All primary ASTQT autograft ACLRs within a single surgeon's prospectively collected registry with minimum 6-month follow-up were included. Patients who underwent multiligament knee reconstruction or cartilage restoration procedures were excluded. Localized anterior arthrofibrosis was defined as the requirement for a second procedure to achieve debridement and lysis of adhesions owing to the inability to regain terminal extension within 6 months of ACLR. The sex-specific incidence of arthrofibrosis was evaluated relative to age, weight, femoral and tibial tunnel sizes, meniscal repair, and meniscectomy by a binary logistic regression.

RESULTS

This study included 721 patients (46% female patients). There were 52 cases of localized anterior arthrofibrosis (7.2%). Female patients had a greater incidence of arthrofibrosis than male patients. Male patients with a femoral tunnel diameter of 9.25 mm or greater had an increased incidence of arthrofibrosis compared with those with a diameter of less than 9.25 mm, whereas a similar cutoff was not found to be statistically significant for female patients. Concomitant meniscal repair was associated with an increased risk of arthrofibrosis.

CONCLUSIONS

Female sex and concomitant meniscal repair were associated with an increased localized anterior arthrofibrosis incidence. Furthermore, ASTQT with a femoral tunnel diameter of 9.25 mm or greater in male patients was associated with an increased incidence of arthrofibrosis. LEVEL OF EVIDENCE: Level III, retrospective, comparative prognostic trial.

RANTES Concentration at the Time of Surgery Is Associated With Postoperative Stiffness in Patients Undergoing ACL Reconstruction

BACKGROUND

Patients undergoing anterior cruciate ligament (ACL) reconstruction have been shown to be at risk for postoperative arthrofibrosis. Diagnostic biomarkers associated with the development of postoperative stiffness are unknown.

HYPOTHESIS

Biomarkers found in the synovial fluid at the time of surgery are associated with the development of postoperative arthrofibrosis in a cohort of patients undergoing ACL reconstruction.

STUDY DESIGN

Case-control study; Level of evidence, 3.

METHODS

Patients undergoing ACL reconstruction were prospectively enrolled. Synovial fluid was collected before surgical incision. A cohort of patients with postoperative stiffness requiring manipulation under anesthesia (MUA) and/or lysis of adhesions (LOA) was retrospectively identified. Matching of cases to controls was performed using a 1:2 pair matching algorithm. Risk factor-adjusted single-biomarker and multivariable models were used to assess the association of synovial fluid biomarkers with postoperative stiffness requiring MUA/LOA. Stepwise logistic regression controlling for clinical risk factors was used to identify biomarkers that are possible predictors of postoperative stiffness.

RESULTS

A total of 11 cases (3 male, 8 female) were identified and matched with 21 controls (6 male, 15 female) with no significant differences in age, sex, smoking history, or days from injury to surgery. Concentrations of the biomarker regulated upon activation, normal T-cell expressed and presumably secreted (RANTES) were significantly higher in patients requiring MUA/LOA versus controls (694.20 pg/mL [interquartile range, 214.75-3428.79] vs 113.04 pg/mL [interquartile range, 32.81-517.91], respectively; P = .034). On single-biomarker models, RANTES (odds ratio, 2.28; 95% CI, 1.29-5.37; P = .019) and basic fibroblast growth factor (bFGF) (odds ratio, 1.91; 95% CI, 1.07-3.99; P = .047) were associated with increased risk of postoperative stiffness requiring MUA/LOA after ACL reconstruction. Stepwise logistic regression identified 3 biomarkers that are possible predictors of postoperative stiffness, which were included in the final model: Interleukin 1 receptor antagonist (IL-1RA) (P = .198), bFGF (P = .157), and RANTES (P = .046).

CONCLUSION

Higher concentrations of synovial fluid biomarkers bFGF and RANTES were associated with increased risk for stiffness requiring intervention after ACL reconstruction. Interleukin 6 (IL-6), vascular endothelial growth factor A (VEGF-A), tissue inhibitor of metalloproteinases 1 (TIMP-1), interleukin 1 receptor antagonist (IL-1RA), matrix metalloproteinase 3 (MMP-3), monocyte chemotactic protein 1 (MCP-1), and macrophage inflammatory protein 1B (MIP-1B) were not associated with the development of postoperative arthrofibrosis.

A novel mouse model of hindlimb joint contracture with 3D-printed casts

Stiff joints formed after trauma, surgery or immobilization are frustrating for surgeons, therapists and patients alike. Unfortunately, the study of contracture is limited by available animal model systems, which focus on the utilization of larger mammals and joint trauma. Here we describe a novel mouse-based model system for the generation of joint contracture using 3D-printed clamshell casts. With this model system we are able to generate both reversible and irreversible contractures of the knee and ankle. Four- or 8-month-old female mice were casted for either 2 or 3 weeks before liberation. All groups formed measurable contractures of the knee and ankle. Younger mice immobilized for less time formed reversible contractures of the knee and ankle. We were able to generate irreversible contracture with either longer immobilization time or the utilization of older mice. The contracture formation translated into differences in gait, which were detectable using the DigiGait® analysis system. This novel model system provides a higher throughput, lower cost and more powerful tool in studying the molecular and cellular mechanisms considering the large existing pool of transgenic/knockout murine strains.

TWO TO 14 YEAR OUTCOMES OF COMBINED MENISCAL ALLOGRAFT TRANSPLANTATION WITH ANTERIOR CRUCIATE LIGAMENT RECONSTRUCTION: A SYSTEMATIC REVIEW

PURPOSE

To evaluate the clinical outcomes of anterior cruciate ligament reconstruction (ACLR) with meniscal allograft transplantation (MAT) through systematic review of current available evidence.

METHODS

A systematic database search of PubMed, Embase, Web of Science and CINAHL was performed from inception up to 7 December 2021 in accordance with the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA). Follow-up studies (inception cohort studies/non-randomized controlled trials/retrospective cohort studies) and case series that had more than 10 people published in English, which involved patients who underwent a combination of ACLR and MAT were included. Quality of these studies were appraised using the Cochrane Risk Of Bias In Non-randomized Studies of Interventions (ROBINS-I) tool. Systematic review of International Knee Documentation Committee (IKDC), Lysholm and Tegner activity scores were conducted.

RESULTS

Seven studies involving 363 patients were included. The average mean follow up time was 4.08 years, ranging from 1.75 to 14 years. All studies used the Lysholm Knee Scoring system to report clinical outcomes, while two studies and four studies used the IKDC Questionnaire and Tegner activity scale respectively to measure clinical outcomes post-operatively. Comparing postoperative to pre-operative scores, we found an improvement above the minimal clinically important difference (MCID) for the Lysholm (Mean Difference (MD) range= 16.00 to 26.10) and Tegner activity scores (MD range = 1.50 to 1.90). All but one study reported an increase above the MCID for IKDC scores post-op (MD range= 5.60 to 23.00).

CONCLUSIONS

Combined MAT and ACLR have good two to 14 year clinical outcomes post operatively and is an optimal procedure for patients with concurrent ACL injuries with irreparable meniscus injuries. More prospective studies and studies evaluating outcome differences between concurrent ACLR with MAT and staged ACLR with MAT should be conducted.

LEVEL OF EVIDENCE

IV, systematic review and/or meta-analysis of studies with Levels I to IV.

Sex-based differences in the severity of radiation-induced arthrofibrosis

As cancer survivorship increases, so does the number of patients that suffer from the late effects of radiation therapy. This includes arthrofibrosis, the development of stiff joints near the field of radiation. Previous reports have concentrated on skin fibrosis around the joint but largely ignored the deeper tissues of the joint. We hypothesized that fat, muscle, and the joint tissues themselves would play a more significant role in joint contracture after radiation than the skin surrounding the joint. To address this hypothesis, we irradiated the right hind flanks of mice with fractionated and unfractionated dose schedules, then monitored the mice for 3 months postradiotherapy. Mice were euthanized and physiological indications of arthrofibrosis including limb contracture and joint resting position were assessed. Stifle (knee) joints demonstrated significant arthrofibrosis, but none was observed in the hock (ankle) joints. During these studies, we were surprised to find that male and female mice showed a significantly different response to radiation injury. Female mice developed more injuries, had significantly worse contracture, and showed a greater difference in the expression of all markers studied. These results suggest that women undergoing radiation therapy might be at significantly greater risk for developing arthrofibrosis and may require specific adjustments to their care.

No increased rate of cyclops lesions and extension deficits after remnant-preserving ACL reconstruction using the sparing technique

BACKGROUND

Remnant-preserving anterior cruciate ligament reconstruction (ACLR) should have advantages for postoperative remodeling and proprioception. However, it has been suggested that the larger diameter of the graft tends to lead to impingement phenomena with a higher rate of cyclops lesions. The aim of this work was to find out whether the remnant-preserving ACLR actually leads to an increased rate of range of motion restraints compared to the remnant-sacrificing technique.

METHODS

Patients, who fulfilled the inclusion criteria, were followed up for one year after surgery. The primary endpoint was arthrolysis due to extension deficit or cyclops syndrome. Secondary outcome measures were pain (NRS), knee function (KOOS), patient satisfaction and return to sports rate.

RESULTS

One hundred and sixty-four patients were included in the study, 60 of whom received the "remnant augmentation" procedure (group 1). In the remnant augmentation group, one cyclops resection was performed, whereas in the non-remnant augmentation group three cyclops lesion resections had to be performed (odds ratio 0.6). There was no difference between the groups in pain (NRS) and knee function (KOOS) and patient satisfaction. The return to sports rate after one year was higher in the remnant augmentation group.

CONCLUSIONS

Patients who have undergone the sparing "remnant augmentation" ACLR have no increased risk of cyclops lesion formation or extension deficit in the first year after surgery. An improvement of the proprioceptive abilities by remnant augmentation ACLR should be investigated in further studies.

LEVEL OF EVIDENCE

III (prospective cohort study).

Predictors of Mid- to Long-Term Outcomes in Patients Experiencing a Knee Dislocation: A Systematic Review of Clinical Studies

Knee dislocations (KDs) are devastating injuries for patients and present complex challenges for orthopaedic surgeons. Although short-term outcomes have been studied, there are few long-term outcomes of these injuries available in the literature. The purpose of this study is to determine factors that influence mid- to long-term clinical outcomes following surgical treatment of KD. A review of the current literature was performed by searching PubMed, the Cochrane Library, and Embase to identify clinical studies published from 2010 to 2019 with a minimum 2-year follow-up that reported outcomes following surgical treatment of KDs. Ten studies (6 level III, 4 level IV) were included. At mid- (2-10 y) to long-term (>10 y) follow-up, concomitant arterial, cartilage, and combined meniscus damage were predictive factors for inferior Lysholm and International Knee Documentation Committee (IKDC) scores when compared with patients without these associated injuries. Although concomitant neurological damage may influence short-term outcomes due to decreased mobility, at longer follow-up periods it does not appear to predict worse clinical outcomes when compared with patients without concomitant neurological injury. Frank and polytrauma KDs have been associated with worse mid- to long-term outcomes when compared with transient and isolated KDs. Patients who underwent surgery within 6 weeks of trauma experienced better long-term outcomes than those who underwent surgery longer than 6 weeks after the initial injury. However, the small sample size of this study makes it difficult to make valid recommendations. Lastly, female sex, patients older than 30 years at the time of injury and a body mass index (BMI) greater than 35 kg/m² are factors that have been associated with worse mid- to long-term Lysholm and IKDC scores. The results of this review suggest that female sex, age >30 years, BMI >35 kg/m², concomitant cartilage damage, combined medial and lateral meniscal damage, KDs that do not spontaneously relocate, and KDs associated with polytrauma may predict worse results at mid- to long-term follow-up.

Imaging Findings of Complications After Lateral Extra-Articular Tenodesis of the Knee: A Current Concepts Review

Background:

Despite successful anterior cruciate ligament (ACL) reconstruction, many patients continue to experience persistent anterolateral rotatory instability. Lateral extra-articular tenodesis (LET) is used to address this instability by harvesting a portion of the iliotibial band, passing it underneath the fibular collateral ligament, and attaching it just proximal and posterior to the lateral femoral epicondyle. Based on the most recent clinical evidence, the addition of LET to ACL reconstruction improves clinical outcomes, which has led to an increase in the use of this technique.

Purpose:

To provide an overview of the postoperative complications of the LET procedure and their associated imaging findings, with a focus on magnetic resonance imaging (MRI).

Study Design:

Narrative review.

Methods:

In this scoping review, the authors reviewed available radiographic, computed tomography, and MRI scans of patients who experienced postoperative complications after ACL reconstruction with LET, in which the complication was determined to be from the LET procedure. Images were reviewed and subsequently described by an on-staff musculoskeletal radiologist.

Results:

The authors found 9 different complications associated with LET: graft failure, hematoma, infection, chronic pain, tunnel convergence, fixation device migration, muscular hernia, peroneal nerve palsy, and knee stiffness. They supplemented these findings with radiographic evidence from 6 patients.

Conclusion:

As extra-articular reconstruction techniques including LET become more popular among orthopaedic surgeons, it is important that radiologists and surgeons be adept at recognizing the normal imaging findings of LET and associated complications.

Postoperative Anterior Cruciate Ligament Reconstruction Quadricep and Patella Tendon Rupture, Infection, and Lysis of Adhesions Decreased Despite Changing Graft Trends Over the Past Decade

Purpose

To investigate recent trends in postoperative complications following anterior cruciate ligament (ACL) reconstruction.

Methods

Patients who underwent ACL reconstruction surgery were identified in a national insurance database and separated into 2 cohorts based on the date of their initial surgery comprising the years 2010 to 2012 and 2016 to 2018, respectively. Patients were matched 1:1 based on comorbidities and Elixhauser Comorbidity Index. All patients were assessed for postoperative complications within 18 months of surgery. Rate of complication was compared between cohorts.

Results

Overall, the all-cause complication rate was 2%. There were significantly more quadriceps tendon rupture, patella tendon rupture, lysis of adhesion, and infection in the early cohort. There were significantly more instances of deep vein thrombosis in the late cohort. We found no significant difference in manipulations under anesthesia between the 2 cohorts.

Conclusions

Patients who underwent surgery in the late cohort had lower rates of postoperative complications, except for deep vein thrombosis. The rate of postoperative quadriceps tendon rupture decreased despite considerable increase in the use of quadriceps tendon autograft.

Clinical Relevance

As there has been an increased use of quadriceps tendon autografts, but little is known about the postoperative complications after ACL reconstruction with these grafts. This information has the potential to improve patient outcomes.

Efficacy of non-operative treatment of patients with knee arthrofibrosis using high-intensity home mechanical therapy: a retrospective review of 11,000+ patients

Background

Recovery from knee surgery or injury can be hindered by knee arthrofibrosis, which can lead to motion limitations, pain and delayed recovery. Surgery or prolonged physical therapy are often treatment options for arthrofibrosis, but they can result in increased costs and decreased quality of life. A treatment option that can regain lost motion without surgery would help minimize risks and costs for the patient. The purpose of this study was to determine treatment efficacy of high-intensity home mechanical stretch therapy in patients with knee arthrofibrosis.

Methods

Records were reviewed for 11,000+ patients who were prescribed a high-intensity stretch device to regain knee flexion. Initial and last recorded knee flexion and days between measurements were available for 9842 patients (Dataset 1). Dataset 2 was a subset of 966 patients from Dataset 1. These 966 patients had separate more rigorous measurements available from physical therapy notes (Dataset 3) in addition to data from the internal database (Dataset 2). Within and between dataset statistics were calculated using t tests for comparison of means and Cohen’s d for determination of effect size.

Results

All dataset showed significant gains in flexion (p < 0.01). Mean initial flexion, last recorded flexion and flexion gain were 79.5°, 108.4°, and 29.9°, respectively in Dataset 1. Differences between Datasets 2 and 3 had small effect sizes (Cohen’s d < 0.17). The were no significant differences when comparing workers’ compensation and non-workers’ compensation patients. The average last recorded flexion for all datasets was above the level required to perform activities of daily living. Motion gains were recorded in under 60 days from device delivery.

Conclusions

High-intensity home mechanical stretch therapy was effective in restoring knee flexion, generally in 2 months or less, and in avoiding additional surgery in severe motion loss patients regardless of sex, age, or workers’ compensation status. We believe high-intensity stretching should be considered in any patient who is at risk for a secondary motion loss surgery, because in over 90% of these patients, the complications and costs associated with surgery can be avoided.

Comparison of Rapid Rehabilitation after Anterior Cruciate Ligament Reconstruction with Tensioning Technique and Traditional Rehabilitation

To investigate the efficacy of a fast rehabilitation program for the recovery of knee joint function after arthroscopic autologous hamstring tendon transplantation for reconstruction of the anterior cruciate ligament (ACL), from January 1, 2017, to March 31, 2019, a total of 65 patients with ACL injury were randomly divided into a study group and a control group. Both groups were treated with autologous hamstring tendon to reconstruct the anterior cruciate ligament, arthroscopic transplantation, and decompression techniques. The research group was treated with a fast rehabilitation program. The control group was treated with traditional rehabilitation program. Knee flexion angles were measured at 2, 4, and 8 weeks postoperatively. KT-1000 knee anterior stability was measured at 3, 6, and 12 months after operation. Knee function was assessed by subjective knee function assessment scale (IKDC) and Lysholm knee score. The knee curvature, KT-1000 measurement, IKDC score, and Lysholm score were compared between the two groups before and after treatment. KT-1000 measured value, IKDC score, and Lysholm score in 2 groups were significantly improved 3, 6, and 12 months compared with those before treatment, and the difference was statistically significant (P < 0.001). Comparison between the two groups: 2 weeks, 4 weeks, and 8 weeks after treatment, the knee curvature in the study group was better than that in the control group, and the difference was statistically significant (P < 0.001); there was no significant difference in the measured values of KT-1000 between the two groups 3, 6, and 12 months after treatment (P > 0.05); IKDC score and Lysholm score in the study group 3 and 6 months after treatment were significantly better than those in the control group, with statistical significance (P < 0.001); there was no significant difference in IKDC score and Lysholm score between the two groups 12 months after treatment (P >0.05). Autograft hamstring tendon transplantation and tense-reducing technique for anatomical reconstruction of anterior cruciate ligament under arthroscopy combined with rapid rehabilitation program can quickly, safely, and effectively restore the knee function of patients, greatly shortening the rehabilitation period of patients.

Early Identification of Arthrofibrosis in Adolescents Following Anterior Cruciate Ligament Reconstruction Is Associated With the Need for Subsequent Surgery: A Matched Case-Control Study

PURPOSE

To identify the postoperative characteristics associated with the need for subsequent surgical intervention in pediatric anterior cruciate ligament reconstruction (ACLR).

METHODS

Patients ≤18 years old who received operative treatment for arthrofibrosis following ACLR versus age- and sex-matched controls with a satisfactory postoperative course were retrospectively reviewed. The range of knee motion preoperatively and at each postoperative visit was recorded. Based on the typical post-operative protocols, visits were categorized into 3 groups: first (first 4 weeks), second (weeks 5-8), and third (weeks 9-16) visits. The deficit in the total arc of range of motion (ROM) in the operative knee relative to the nonoperative knee and the change in ROM between visits were compared. Receiver operating characteristic analysis was performed to determine the time point in which a diagnosis of arthrofibrosis could be predicted with the greatest accuracy.

RESULTS

In total, 18 patients with arthrofibrosis (mean age 14.2 ± 2.7 years, 9 male) and 36 control patients were included in the final analysis. Arthrofibrosis patients had significantly larger ROM deficits at all visits, 93° vs 69° for the first, 69° vs 24° for the second, and 56° vs 2º for the third, compared with controls (P < .001 for all). Pairwise comparisons showed that in arthrofibrosis cases, the total ROM did not change significantly between the second and third visits (P = .77), contrary to the controls. Receiver operating characteristic analysis revealed that the total ROM deficit of 50.7° at the second postoperative visit is 89% sensitive and 92.5% specific for development of arthrofibrosis.

CONCLUSIONS

We found that patients who go on to need manipulation of the knee under anesthesia/arthroscopic lysis of adhesions do not experience a significant improvement in ROM after the first 5-8 weeks, and that a ROM deficit of >50° at the 5- to 8-week mark postoperatively, is associated with ultimately needing operative intervention for arthrofibrosis. Based on these findings, it may be appropriate to intervene earlier if a patient still has a ROM deficit exceeding 50° by the second postoperative month.

LEVEL OF EVIDENCE

Level III, retrospective comparative prognostic trial.

Treatment of arthrofibrosis and stiffness after total knee arthroplasty: an updated review of the literature

PURPOSE

There is currently no consensus regarding the optimal treatment for stiffness following total knee arthroplasty (TKA). With the increased utilization of value-based models, it is important to determine the most effective treatments that will reduce the need for further intervention and additional expenditure. A systematic review was performed to compare the outcomes of manipulation under anaesthesia (MUA), arthroscopic lysis of adhesions (aLOA), and revision TKA (rTKA) for arthrofibrosis and stiffness following TKA.

METHODS

PubMed and MEDLINE databases were reviewed for articles published through October 2020. Studies were included if they reported patient-reported outcome measures (PROMs) following MUA, aLOA, or rTKA. The primary endpoint was PROMs, while secondary outcomes included range of motion and the percentage of patients who pursued further treatment for stiffness.

RESULTS

A total of 40 studies were included: 21 on rTKA, 7 on aLOA, and 14 on MUA. The mean or median post-operative arc ROM was > 90° in 6/20 (30%) rTKA, 5/7 (71%) aLOA, and 7/10 (70%) MUA studies. Post-operative Knee Society (KSS) clinical and functional scores were the greatest in patients who underwent MUA and aLOA. As many as 43% of rTKA patients required further care compared to 25% of aLOA and 17% of MUA patients.

CONCLUSION

Stiffness following TKA remains a challenging condition to treat. Nonetheless, current evidence suggests that patients who undergo rTKA have poorer clinical outcomes and a greater need for further treatment compared to patients who undergo MUA or aLOA.

Arthrofibrosis Nightmares: Prevention and Management Strategies

Arthrofibrosis (AF) is an exaggerated immune response to a proinflammatory insult leading to pathologic periarticular fibrosis and symptomatic joint stiffness. The knee, elbow, and shoulder are particularly susceptible to AF, often in the setting of trauma, surgery, or adhesive capsulitis. Prevention through early physiotherapeutic interventions and anti-inflammatory medications remain fundamental to avoiding motion loss. Reliable nonoperative modalities exist and outcomes are improved when etiology, joint involved, and level of dysfunction are considered in the clinical decision making process. Surgical procedures should be reserved for cases recalcitrant to nonoperative measures. The purpose of this review is to provide an overview of the current understanding of AF pathophysiology, identify common risk factors, describe prevention strategies, and outline both nonoperative and surgical treatment options. This manuscript will focus specifically on sterile AF of the knee, elbow, and shoulder.

Arthrofibrosis following primary total hip arthroplasty: a distinct clinical entity

INTRODUCTION

Arthrofibrosis is a relatively frequent complication after total knee arthroplasty. Although stiffness after total hip arthroplasty (THA), because of formation of heterotopic ossification or other causes, is not uncommon, to the authors' best knowledge, arthrofibrosis after THA has not been described. The aim of this study is to describe the arthrofibrosis of the hip after primary THA using an established clinical and histological classification of arthrofibrosis.

MATERIALS AND METHODS

We retrospectively examined all patients who were histologically confirmed to have arthrofibrosis after primary THA during revision surgery by examination of tissue samples in our clinic. Arthrofibrosis was diagnosed according to the histopathological SLIM-consensus classification, which defines seven different SLIM types of the periimplant synovial membrane. The SLIM type V determines the diagnosis of endoprosthesis-associated arthrofibrosis.

RESULTS

The study population consists of 66 patients who were revised due to arthrofibrosis after primary THA. All patients had a limitation in range of motion prior to revision with a mean flexion of 90° (range from 40 to 125), mean internal rotation of 10° (range from 0 to 40) and mean external rotation of 20° (range from 0 to 50). All patients had histological SLIM type V arthrofibrosis, corresponding to endoprosthesis-associated arthrofibrosis. Histological examination revealed that seven patients (10.6%) had particle-induced and 59 patients (89.4%) had non-particle-induced arthrofibrosis.

CONCLUSION

This is the first description of endoprosthetic-associated arthrofibrosis after primary THA on the basis of a well-established histological classification. Our study results could enable new therapeutic and diagnostic opportunities in patients with such an arthrofibrosis. Surgeons should keep arthrofibrosis as a possible cause for stiffness and pain after primary THA in mind.

LEVEL OF EVIDENCE

Diagnostic study, Level of Evidence IV.

Does Flipping the Tubercle for Improved Cartilage Repair Exposure Increase the Risk for Arthrofibrosis?

OBJECTIVE

We sought to determine whether rates of postoperative arthrofibrosis following tibial tuberosity osteotomy (TTO) with complete mobilization of the fragment (TTO-HD) are comparable to TTOs where the hinge remained intact (TTO-HI).

DESIGN

Patients who underwent TTO with concomitant cartilage repair procedure between January 2007 and May 2017, with at least 2 years of follow-up were included in this study. Postoperative reinterventions following TTO-HD and TTO-HI were assessed and multivariant logistic regression models were used to identify whether postoperative reinterventions can be attributed to either technique when controlled for defect size or defect number.

RESULTS

A total of 127 patients (TTO-HD, n = 80; TTO-HI, n = 47) were included in this study. Significantly more patients in the TTO-HD group (31.2%) developed postoperative arthrofibrosis compared with TTO-HI (6.4%; P < 0.05). Multivariant logistic regression revealed that TTO-HD is an independent risk factor for predicting postoperative arthrofibrosis (OR 6.5, CI = 1.7-24.2, P < 0.05).

CONCLUSION

Patients who underwent TTO with distal hinge detachment and a proximally flipped tubercle for better exposure during concomitant cartilage repair were at a significantly higher risk of postoperative arthrofibrosis than patients with similar size and number of defects treated without mobilization of the tubercle. While certain procedures can benefit from larger exposure, surgeons should be aware of the increased risk of postoperative arthrofibrosis.

LEVEL OF EVIDENCE

Level III, case-control study.

Current and future of anterior cruciate ligament reconstruction techniques

In recent years, anterior cruciate ligament (ACL) reconstruction has generally yielded favorable outcomes. However, ACL reconstruction has not provided satisfactory results in terms of the rate of returning to sports and prevention of osteoarthritis (OA) progression. In this paper, we outline current techniques for ACL reconstruction such as graft materials, double-bundle or single-bundle reconstruction, femoral tunnel drilling, all-inside technique, graft fixation, preservation of remnant, anterolateral ligament reconstruction, ACL repair, revision surgery, treatment for ACL injury with OA and problems, and discuss expected future trends. To enable many more orthopedic surgeons to achieve excellent ACL reconstruction outcomes with less invasive surgery, further studies aimed at improving surgical techniques are warranted. Further development of biological augmentation and robotic surgery technologies for ACL reconstruction is also required.

Effects of Each Phase of Anterior Cruciate Ligament Reconstruction Surgery on Joint Contracture in Rats

BACKGROUND

Although anterior cruciate ligament reconstruction surgery is known to cause joint contracture, the mechanisms of this process are unknown. We aimed to assess the effects of transection of this ligament and each phase of reconstruction surgery on contracture formation.

MATERIALS AND METHODS

Rats were divided into groups according to treatment received: sham (arthrotomy), ligament transection, ligament transection plus bone drilling, and ligament reconstruction. Surgery was performed on the right knee. Untreated left knees in the sham group were used as controls.

RESULTS

At 7 and 28 d post-surgery, range of motion before myotomy, mainly representing myogenic contracture, was restricted in the sham and ligament transection groups, and more so in the bone drilling and reconstruction groups. Restricted range of motion after myotomy, representing arthrogenic contracture, was detected at both timepoints in the bone drilling and reconstruction groups, but not in the sham or ligament transection groups. At 3 d post-surgery, although a large blood clot was observed in all three treatment groups, only the bone drilling and reconstruction groups showed significant joint swelling. At 7 d post-surgery, inflammatory-cell infiltration into the joint capsule was most apparent in the bone drilling and reconstruction groups, and joint capsule fibrosis was also most apparent in these groups at 7 and 28 d post-surgery.

CONCLUSIONS

Our results suggest that (1) myogenic contracture after anterior cruciate ligament reconstruction is caused by arthrotomy and aggravated by bone drilling, and (2) arthrogenic contracture is mostly due to bone drilling, which triggers an inflammation-fibrosis cascade.

Gender differences in knee kinematics during weight-bearing knee flexion for patients with arthrofibrosis after anterior cruciate ligament reconstruction

Background

Knowledge of tibiofemoral and patellofemoral joint kinematics is important for understanding gender-related dimorphism in developing knee arthrofibrosis and advancement of related treatments. The objective of our study was to investigate gender differences existing in tibiofemoral kinematics and patellar tracking in patients with arthrofibrosis after anterior cruciate ligament (ACL) reconstruction during weight-bearing knee flexion.

Methods

The tibiofemoral and patellofemoral joint kinematics were measured in 30 patients (15 male and 15 female) with arthrofibrosis after ACL reconstruction during a lunge task, using computed tomography and dual fluoroscopic imaging system. These data were analyzed for gender differences.

Results

The range of tibial rotation, patellar inferior shift, tilt, and flexion were significantly decreased in the affected knee compared to the contralateral knee from 15° to 75° of knee flexion (P ≤ 0.04). Statistically significant difference was detected for medial tibial translation between male and female patients at 60° (P = 0.04) and 75° of knee flexion (P = 0.02). The tibial rotation was significantly decreased at 60° (P = 0.03) and 75° of knee flexion (P < 0.01) in females. The inferior patellar shift in females was significantly lower than that in males at 15° (P = 0.04) and 30° of knee flexion (P = 0.01). The patellar tilt was significantly lower at 60° (P = 0.02) and 75° of knee flexion (P < 0.01) in females compared to males.

Conclusions

The results indicated a significant effect of gender on knee kinematics in patients with arthrofibrosis after ACL reconstruction during weight-bearing knee flexion. These gender differences in tibiofemoral kinematics and patellar tracking may warrant further investigations to determine implications for making gender-specific surgical treatments and rehabilitation programs.

Analysis of intercondylar notch size and shape in patients with cyclops syndrome after anterior cruciate ligament reconstruction

Background

Cyclops lesion is the second most common cause of extension loss after anterior cruciate ligament reconstruction. This study focused on the correlation between the anatomy of the intercondylar notch and the incidence of cyclops lesion. To determine whether the size and shape of the intercondylar notch are related to cyclops lesion formation following anterior cruciate ligament reconstruction according to magnetic resonance imaging (MRI) findings.

Methods

One hundred twenty-five (125) patients were retrospectively evaluated. The notch width index (NWI) and notch shape index (NSI) were measured based on coronal and axial MRI sections in patients diagnosed with cyclops syndrome (n = 25), diagnosed with complete anterior cruciate ligament (ACL) tears (n = 50), and without cyclops lesions or ACL ruptures (n = 50).

Results

Imaging analysis results showed that the cyclops and ACL groups had lower mean NWI and NSI values than the control group. Significant between-group differences were found in NSI (p = 0.0140) based on coronal cross-sections and in NWI (p = 0.0026) and NSI (p < 0.0001) based on axial sections.

Conclusions

The geometry of the intercondylar notch was found to be associated with the risk of cyclops lesion formation and ACL rupture.

Terminal knee extension deficit and female sex predict poorer quadriceps strength following ACL reconstruction using all-soft tissue quadriceps tendon autografts

PURPOSE

The all-soft tissue quadriceps tendon (QT) autograft is becoming increasingly popular for ACL reconstruction (ACLR); however, studies reporting strength recovery and early outcomes after QT autograft are limited with patient samples composed of predominantly males. The primary purpose was to characterize early, sex-specific recovery of strength, range of motion (ROM), and knee laxity in a large cohort of patients undergoing primary ACLR with standardized harvest technique of the all-soft tissue QT autograft. The secondary purpose was to examine the influence of demographic factors and clinical measures on 6-month quadriceps strength.

METHODS

Patients 14-25 years who underwent primary, unilateral ACLR with all-soft tissue QT autografts were prospectively followed. Knee laxity and ROM were collected at 6 weeks, 3 and 6 months; while, quadriceps normalized torques and limb symmetry indices (LSI) were collected at 3 and 6 months using isokinetic dynamometry at 60°/s. Two-way ANOVAs with repeated measures were conducted to determine recovery over time and between sexes. Stepwise linear multiple regressions were conducted to determine predictors of 6-month quadriceps strength.

RESULTS

Three-hundred and twenty patients were included (18 ± 3 years; 156 males:164 females; BMI = 24 ± 4 kg/m²) with no early graft failures within the study period. For strength, there were significant main effects of time (p < 0.001) and sex (p < 0.001), indicating similar improvement from 3 to 6 months with males demonstrating greater quadriceps LSI (6 months: 72.1 vs 63.3%) and normalized strength (6 months: 2.0 vs 1.6 Nm/kg). A significantly higher proportion of females had knee extension ROM deficits ≥ 5° compared to males at 6 weeks (61 vs 39%; p = 0.002). Female sex and 3-month extension ROM deficits were identified as significant predictors of 6-month quadriceps LSI (R² = 0.083; p < 0.001). Female sex, BMI, and 6-week extension ROM deficits were identified as significant predictors of 6-month normalized quadriceps strength (R² = 0.190; p < 0.001).

CONCLUSIONS

Females had decreased quadriceps strength and greater extension ROM deficits at 3 and 6 months following ACLR using all-soft tissue QT autografts. Female sex, higher BMI, and loss of extension ROM were independent predictors of poorer quadriceps strength at 6 months. There were no early graft failures, and laxity remained within normal ranges for both males and females. Surgeons and rehabilitation clinicians should be aware of the increased risk of postoperative loss of extension ROM in females and its implications on quadriceps strength recovery.

LEVEL OF EVIDENCE

III.

Sustained Delivery of SB-431542, a Type I Transforming Growth Factor Beta-1 Receptor Inhibitor, to Prevent Arthrofibrosis

Fibrosis of the knee is a common disorder resulting from an aberrant wound healing response and is characterized by extracellular matrix deposition, joint contraction, and scar tissue formation. The principal regulator of the fibrotic cascade is transforming growth factor beta-1 (TGF-β1), a factor that induces rapid proliferation and differentiation of resident fibroblasts. In this study, we demonstrate successful inhibition of TGF-β1-driven myofibroblastic differentiation in human fibroblast-like synoviocytes using a small molecule TGF-β1 receptor inhibitor, SB-431542. We also demonstrate successful encapsulation of SB-431542 in poly(D,L-lactide-co-glycolide) (PLGA) as a potential prophylactic treatment for arthrofibrosis and characterize drug release and bioactivity in a three-dimensional collagen gel contraction assay. We assessed the effects of TGF-β1 and SB-431542 on cell proliferation and viability in monolayer cultures. Opposing dose-dependent trends were observed in cell proliferation, which increased in TGF-β1-treated cultures and decreased in SB-431542-treated cultures relative to control (p < 0.05). SB-431542 was not cytotoxic at the concentrations studied (0-50 μM) and inhibited TGF-β1-induced collagen gel contraction in a dose-dependent manner. Specifically, TGF-β1-treated gels contracted to 18% ± 1% of their initial surface area, while gels treated with TGF-β1 and ≥10 μM SB-431542 showed no evidence of contraction (p < 0.0001). Upon removal of the compound, all gels contracted to control levels after 44 h in culture, necessitating sustained delivery for prolonged inhibition. To this end, SB-431542 was encapsulated in PLGA microspheres (SBMS) that had an average diameter of 87.5 ± 24 μm and a loading capacity of 4.3 μg SB-431542 per milligram of SBMS. Functional assessment of SBMS revealed sustained inhibition of TGF-β1-induced gel contraction as well as hallmark features of myofibroblastic differentiation, including α-smooth muscle actin expression and connective tissue growth factor production. These results suggest that SB-431542 may be used to counter TGF-β1-driven events in the fibrotic cascade in the knee cartilage.

A rat model of arthrofibrosis developed after anterior cruciate ligament reconstruction without rigid joint immobilization

Purpose: Complications including arthrofibrosis have been reported after anterior cruciate ligament reconstruction (ACLR) even under accelerated rehabilitation. To overcome this, we developed an animal model of ACLR-induced arthrofibrosis without immobilization.Materials and Methods: Thirteen male Wistar rats were divided into ACL transection (ACLT) and ACLR groups. Surgery was performed in the right knees and untreated left knees were used as controls. After surgery, rats could move freely without joint immobilization.Results: One week after surgery, flexion contracture represented by passive ROM reduction was 49 ± 5° and 21 ± 6° in ACLR and ACLT groups, respectively. Thereafter, flexion contractures were gradually reduced to 21 ± 8° and 12 ± 6° after 12 weeks, respectively. Fibrosis, which is characterized by significant upregulation of fibrosis-related genes, thickening, and adhesion in the posterior joint capsule, was observed in the ACLR group after 12 weeks of surgery. Nociceptive behavior and joint swelling were more apparent in the ACLR group than in the ACLT group, especially after 1 week of surgery.Discussions: We developed a rat model of ACLR-induced joint contracture due to arthrofibrosis without rigid immobilization. Joint contracture was also observed in the ACLT group, but to a considerably milder degree than in the ACLR group. Thus, signs of inflammation as a result of reconstruction surgery, rather than ACL transection, play an important role in the formation of joint contracture after ACLR. Our animal model is suited to examine the mechanisms and efficacy of therapeutic strategies for arthrofibrosis following ACLR treated without rigid joint immobilization.

Risk of arthrofibrosis in anatomical anterior cruciate ligament reconstruction: the role of timing and meniscus suture

BACKGROUND

The optimal timing of anterior cruciate ligament (ACL) reconstruction remains controversial. Several studies have shown that early surgery leads to an increased rate of arthrofibrosis and poorer postoperative function. Other studies found no correlation between time of surgery and arthrofibrosis. The influence of simultaneous meniscus treatment is also discussed. Aim of this study was to ascertain whether the timing of surgery and treatment of meniscus influences the occurrence rate of arthrofibrosis.

METHODS

Two hundred and six patients could be included. These were split into two groups. Group 1: surgery within 6 weeks after ACL rupture (n = 68), group 2: surgery after more than 6 weeks (n = 68). In addition, 2 matched groups were created (n = 138 ). Follow-up was 12 months after surgery. The primary endpoint was the rate of subsequent arthrofibrosis procedures (arthroscopic arthrolysis). Secondary endpoints were knee function (knee osteoarthritis outcome score: KOOS), knee pain (numeric rating scale: NRS) and patient satisfaction measured on a 5 point Likert scale.

RESULTS

In 6 of the 68 patients in group 1 (8.8%) and 3 of the 138 patients in group 2 (2.2%) a subsequent arthroscopic arthrolysis was performed (OR 4.4). A simultaneous meniscal suture was performed in 58 patients (30 of them in group 1). Five of the six patients with subsequent arthrolysis in group 1 received meniscal repair (OR for arthrolysis 3.4). There was no difference between the groups in terms of knee function (KOOS), pain (NRS) and patient satisfaction.

CONCLUSION

The rate of subsequent arthroscopic arthrolysis was higher in the acute surgery group. However, most of these subsequent procedures were associated with meniscal repair at index surgery with a more restrictive rehabilitation protocol than after ACL reconstruction without meniscus repair. This allows the assessment that the meniscal suturing poses an increased risk. Therefore, this allows the conclusion that if using an anatomical surgical technique and considering the signs of inflammation with effusion, pain and movement deficit less than 90° there is no increased risk of arthrofibrosis.

Causes of stiffness after total knee arthroplasty: a systematic review

BACKGROUND

Knee stiffness after total knee arthroplasty (TKA) often leads to pain and discomfort, failing to meet patients' expectations on the surgical procedure. Despite the growing debate on the topic, a comprehensive literature analysis of stiffness causes has never been conducted. Thus, the purpose of the present study was to systematically review the literature regarding the main causes of stiffness after TKA.

METHODS

Pubmed Central, Scopus, and EMBASE databases were systematically reviewed according to the Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) guidelines for studies on stiffness and pain or discomfort after TKA through November 2020. Overall, 25 articles matched the selection criteria and were included in the study. Clinical relevance and strength of evidence of the included studies were graded using the risk of bias and the methodological index for non-randomized studies quality assessment tools.

RESULTS

The main causes of pain and discomfort due to stiffness were surgery-related issues, i.e., component malpositioning and over-voluming, implant loosening, psychological distress, and obesity, which could be considered "modifiable" factors, and expression of profibrotic markers, high material hypersensitivity-related cytokines level, male gender, previous contralateral TKA, and high pre-operative pain, which could be considered "non-modifiable" factors.

CONCLUSION

The use of alternative technologies such as surgical robots, anatomy-based devices, and more inert and less stiff component materials could help in reducing stiffness caused by both modifiable and even some non-modifiable factors. Furthermore, early diagnostic detection of stiffness onset could consistently support surgeons in patient-specific decision-making.

The Prognosis of Arthrofibroses: Prevalence, Clinical Shortcomings, and Future Prospects

Fibrosis is the dysregulated biosynthesis of connective tissue that results from persistent infection, high serum cholesterol, surgery, trauma, or prolonged joint immobilization. As a disease that impacts connective tissue, it is prevalent across the body and disrupts normal extracellular and tissue organization. Ultimately, fibrosis impairs the tissue structural, mechanical, or biochemical function. This review describes the clinical landscape of joint fibrosis, that is, arthrofibrosis, including the risk factors and causes, as well as current clinical treatments and their shortcomings. Because treating arthrofibrosis remains an unmet clinical challenge, we present several animal models used for exploration of the physiopathology of arthrofibrosis and summarize their use for testing novel treatments. We then discuss therapeutics for the prevention or treatment of arthrofibrosis that are in preclinical development and in ongoing clinical trials. We conclude with recent findings from molecular biological studies of arthrofibroses that shed insight on future areas of research for improved treatments.