Acute rotational trauma to the knee: poor agreement between clinical assessment and magnetic resonance imaging findings

Femoral-Obturator-Sciatic (FOS) Nerve Block as an Anesthetic Triad for Arthroscopic ACL Reconstruction: Is This the Magic Trick We Were Missing?

Arthroscopic anterior cruciate ligament (ACL) reconstruction with hamstring grafting is a common orthopedic procedure that is associated with moderate-to-severe pain. Peripheral nerve blockade as an anesthetic technique is an appealing option in the era of modern anesthesia. The aim of this narrative review is to document the efficacy and safety of the combination of femoral, obturator, and sciatic (FOS) nerve blocks as an exclusive method for anesthesia in patients undergoing ACL reconstruction. An electronic search of the literature published up to October 2023 was conducted in the Medline, Embase, Cochrane, Web of Science, and Google Scholar databases to find studies on ACL reconstruction and peripheral obturator nerve block. Overall, 8 prospective studies-with a total of 315 patients-published between 2007 and 2022 were included in this review. Ultrasound-guided peripheral FOS nerve blockade is an effective anesthetic technique for ACL reconstruction, offering good perioperative pain management, minimal opioid consumption, and an excellent safety profile. Further well-designed prospective studies are needed to determine the best approach for obturator nerve blockade and the appropriate type and dosage of local anesthetic.

The effect of attending rehabilitation after traumatic knee joint injury on femoral articular cartilage morphology in collegiate rugby players with a history of intracapsular knee joint injury during two-year consecutive rugby seasons

Introduction

This present study aimed to compare ultrasonographic measures of femoral articular cartilage during two-year seasons between collegiate rugby players who have attended supervised rehabilitation following intracapsular knee joint injury and those without a history of knee injury.

Methods

Using a prospective observational study design, 12 male collegiate rugby players with a previous history of intracapsular knee joint injury who have received and completed supervised rehabilitation following their injury and 44 players without knee joint injury participated in this study. Ultrasonographic images were used to verify changes in femoral articular cartilage thickness and cross-sectional area (CSA) with or without a previous history of knee joint injury over two consecutive rugby seasons.

Results

Significant time main effects were observed for the lateral condylar thickness (p < 0.001), the intercondylar thickness (p = 0.001), the medial condylar thickness (p < 0.001), and CSA (p < 0.001). No significant interactions nor group main effects were identified for all femoral articular cartilage (p < 0.05).

Conclusions

Collegiate rugby players demonstrated a decrease in femoral articular cartilage thickness and CSA over two-year consecutive rugby seasons. These findings indicate that engaging in collegiate rugby induces alterations in femoral articular cartilage structure. Furthermore, there were no differences in all femoral cartilage outcome measures between rugby players with and without a previous history of traumatic knee joint injury. Therefore, attending supervised rehabilitation at the time of their knee joint injury appeared to reduce the impact of a previous history of intracapsular knee joint injury on the change in femoral articular cartilage thickness and CSA among active rugby players.

Construction and validation of a functional diagnostic score in anterior cruciate ligament ruptures of the knee in the immediate post-traumatic period. Preliminary results of a multicenter prospective study

INTRODUCTION

Knee ligament injuries are frequent and their number is constantly increasing with the development of sports activities. Dynamic knee maneuvers usually make it possible to diagnose anterior cruciate ligament (ACL) injuries but they remain difficult to perform in the early post-traumatic phase. This leads to the almost systematic use of MRI scans, many of which turn out to be superfluous. The aim of this study was to construct a screening score based solely on history-taking, in order to help diagnose ACL injuries, and to define thresholds that could help inform recommendations for MRI usage. The hypothesis was that this score could distinguish a population of patients with a ruptured ACL from a population of patients with other knee injuries.

MATERIAL AND METHODS

This prospective multicenter study included 166 patients. Patients were included if they were between 18 and 55 years of age, with knee trauma that had occurred in the last 10 days, and without a bone fracture on standard radiographs. They were excluded if the trauma required immediate surgical management and if they had a history of knee trauma. The screening score was completed by the physician. The score included the following items: assessment of pain, immediate post-traumatic functional impairment, notion of a "pop", feeling of instability and presence of a swelling. An MRI was systematically performed and the patient consulted a referring physician to compare the initial score with the diagnosis.

RESULTS

Eighty-six patients had an injured ACL and 80 had a healthy ACL. Two thresholds could be identified. For a score lower than 4, the risk of an ACL injury was low with a sensitivity of 96% and a negative predictive value of 87%. For a score above 8, the ACL injury was highly probable with a specificity of 88% and a positive predictive value of 83%.

DISCUSSION/CONCLUSION

The score was able to distinguish a population of patients with a ruptured ACL from a population of patients with other knee injuries. These preliminary results confirm that the selected items are relevant and that the score can help improve the diagnostic orientation of patients with recent knee trauma. Increasing the sample size in combination with an analysis of influencing factors will determine whether the performance of this score can be refined.

LEVEL OF EVIDENCE

II prospective multicenter study.

Thigh muscle co-contraction patterns in individuals with anterior cruciate ligament reconstruction, athletes and controls during a novel double-hop test

Efficient neuromuscular coordination of the thigh muscles is crucial in maintaining dynamic knee stability and thus reducing anterior cruciate ligament (ACL) injury/re-injury risk. This cross-sectional study measured electromyographic (EMG) thigh muscle co-contraction patterns during a novel one-leg double-hop test among individuals with ACL reconstruction (ACLR; n = 34), elite athletes (n = 22) and controls (n = 24). Participants performed a forward hop followed by a 45° unanticipated diagonal hop either in a medial (UMDH) or lateral direction (ULDH). Medial and lateral quadriceps and hamstrings EMG were recorded for one leg (injured/non-dominant). Quadriceps-to-Hamstring (Q:H) ratio, lateral and medial Q:H co-contraction indices (CCIs), and medial-to-lateral Q:H co-contraction ratio (CCR; a ratio of CCIs) were calculated for three phases (100 ms prior to landing, initial contact [IC] and deceleration phases) of landing. We found greater activity of the quadriceps than the hamstrings during the IC and deceleration phases of UMDH/ULDH across groups. However, higher co-contraction of medial rather than lateral thigh muscles during the deceleration phase of landing was found; if such co-contraction patterns cause knee adduction, a putative mechanism to decrease ACL injury risk, during the deceleration phase of landing across groups warrants further investigation.

Prospective and Randomized Clinical Evaluation of Hamstring Versus Patellar Tendon Autograft for Anterior Cruciate Ligament Reconstruction in Soccer Players

Background:

Anterior cruciate ligament (ACL) reconstruction is usually performed with autologous bone–patellar tendon–bone (PT) or hamstring tendon (HT) graft. There has been only 1 randomized clinical trial examining ACL reconstruction with these grafts specifically in soccer players, and more studies comparing these graft types within a homogenous cohort such as soccer athletes may better highlight differences in outcomes.

Purpose:

To compare the results of ACL reconstruction with PT versus HT autograft in soccer players and to evaluate objective and subjective outcomes.

Study Design:

Randomized controlled trial; Level of evidence, 1.

Methods:

A total of 62 professional or semiprofessional soccer players (mean age, 25.1 years) with ACL injury were randomized to undergo reconstruction with PT or HT autograft by a single orthopaedic surgeon (n = 31 in each group). Outcome measures were recorded preoperatively and at 2 years postoperatively. The primary outcome was the modified Cincinnati Knee Rating System, and secondary outcomes were the objective and subjective International Knee Documentation Committee scores, Lachman test, pivot-shift test, anterior drawer test, and Lysholm score. The following variables were also evaluated postoperatively: return to soccer, level at return, graft rerupture, postoperative complications, anterior knee pain, patellar tendinitis, difficulty sprinting, and loss of kicking power.

Results:

The PT and HT groups were homogenous in terms of age, sex distribution, injured side, and time from injury to surgery, and there was no difference between them on any preoperative outcome score. At 2 years postoperatively, there were no differences between the groups on any outcome score; however, there were significantly fewer patients with anterior knee pain in the HT group compared with the PT group (7 [22.6%] vs 15 [48.4%], respectively; P = .03). Two patients from each group (2/31; 6.5%) sustained rerupture.

Conclusion:

There were no differences between soccer players who underwent different types of ACL reconstruction with the exception of anterior knee pain, which was more frequent in players who underwent reconstruction with PT graft.

Registration: NCT02642692 (ClinicalTrials.gov).

LEVER SIGN TEST FOR CHRONIC ACL INJURY: A COMPARISON WITH LACHMAN AND ANTERIOR DRAWER TESTS

Objective

This study aims to evaluate the sensitivity and specificity of the lever sign test in patients with and without chronic Anterior Cruciate Ligament (ACL) injuries in an outpatient setting and the inter-examiner agreement of surgeons with different levels of experience.

Methods

72 consecutive patients with a history of previous knee sprains were included. The Lachman, anterior drawer, and Lever Sign tests were performed for all subjects in a randomized order by three blinded raters with different levels of experience. Sensitivity, specificity, positive predictive value, negative predictive value, and inter-rater agreement were estimated for all tests.

Results

Among the 72 patients, the prevalence of ACL injuries was 54%. The lever test showed sensitivity of 64.1% (95% CI 0.47-0.78) and specificity of 100% (95% CI 0.87-1.00) for the senior examiner. For the less experienced examiner the sensitivity was 51.8% and the specificity was 93.7%. Positive predictive values (PPV) and negative predictive values (NPV) were 100% and 70.2%, respectively.

Conclusion

Lever Sign test shows to be a maneuver of easy execution, with 100% specificity and 100% PPV. Moderate agreement between experienced examiners and low agreement among experienced and inexperienced examiners was found. This test may play a role as an auxiliary maneuver. Level of Evidence I, Diagnostic Studies - Investigating a Diagnostic Test.

Differences in Knee Shape between ACL Injured and Non-Injured: A Matched Case-Control Study of 168 Patients

OBJECTIVE

Anterior cruciate ligament (ACL) injury prevention programs could be more effective if we could select patients at risk for sustaining an ACL rupture. The purpose of this study is to identify radiographic shape variants of the knee between patients with and patients without an ACL rupture.

METHODS

We compared the lateral and Rosenberg view X-rays of 168 prospectively followed patients with a ruptured ACL to a control group with intact ACLs, matched for gender, after knee trauma. We used statistical shape modeling software to examine knee shape and find differences in shape variants between both groups.

RESULTS

In the Rosenberg view X-rays, we found five shape variants to be significantly different between patients with an ACL rupture and patients with an intact ACL but with knee trauma. Overall, patients who had ruptured their ACL had smaller, flatter intercondylar notches, a lower lateral tibia plateau, a lower medial spike of the eminence, and a smaller tibial eminence compared to control patients.

CONCLUSION

Patients with an ACL rupture have smaller intercondylar notches and smaller tibial eminences in comparison to patients with an intact ACL after knee trauma.

Anterior Cruciate Ligament Reconstruction Using Bone-Patellar Tendon-Bone Autograft With Suture Tape Augmentation

The anterior cruciate ligament (ACL) is the most commonly injured ligament in the knee, with injury usually occurring as a result of multidirectional sports. The incidence of ACL injury has continued to increase, with most patients opting for surgery to improve stability as well as permit a return to sport. Traditional methods of ACL reconstruction can achieve this but are not without their problems, including graft rupture, residual laxity, and donor-site morbidity. There is therefore a requirement for further research into newer, innovative surgical techniques to help improve complication rates. This article describes, with video illustration, ACL reconstruction using a reduced-size bone-patellar tendon-bone autograft with suture tape augmentation. The augmentation acts as a stabilizer during the early stages of graft incorporation while resisting against reinjury during an accelerated recovery. The ability to use a reduced-size graft decreases the donor-site burden, and retention of residual native ACL tissue, when possible, may help with proprioception.

Thermal and non-thermal effects of capacitive-resistive electric transfer application on different structures of the knee: a cadaveric study

Capacitive-resistive electric transfer therapy is used in physical rehabilitation and sports medicine to treat muscle, bone, ligament and tendon injuries. The purpose is to analyze the temperature change and transmission of electric current in superficial and deep knee tissues when applying different protocols of capacitive-resistive electric transfer therapy. Five fresh frozen cadavers (10 legs) were included in this study. Four interventions (high/low power) were performed for 5 min by a physiotherapist with experience. Dynamic movements were performed to the posterior region of the knee. Capsular, intra-articular and superficial temperature were recorded at 1-min intervals and 5 min after the treatment, using thermocouples placed with ultrasound guidance. The low-power protocols had only slight capsular and intra-capsular thermal effects, but electric current flow was observed. The high-power protocols achieved a greater increase in capsular and intra-articular temperature and a greater current flow than the low-power protocols. The information obtained in this in vitro study could serve as basic science data to hypothesize capsular and intra-articular knee recovery in living subjects. The current flow without increasing the temperature in inflammatory processes and increasing the temperature of the tissues in chronic processes with capacitive-resistive electric transfer therapy could be useful for real patients.

Physical prognostic factors predicting outcome following anterior cruciate ligament reconstruction: protocol for a systematic review

INTRODUCTION

Injuries of the anterior cruciate ligament (ACL) are a common musculoskeletal complication and can cause significant reduction in patient function and quality of life. Many undergo ACL reconstruction, with high-quality rehabilitation key to successful outcome. Knowledge of physical prognostic factors, such as quadriceps strength, is crucial to inform rehabilitation and has important implications for outcome following ACL reconstruction. However, these factors predicting outcome are poorly defined. Therefore, the aim of this systematic review is to establish physical prognostic factors predictive of outcome in adults following ACL reconstruction. Outcome will be subdivided into two groups of outcome measures, patient-reported and performance-based. Physical prognostic factors of interest will reflect a range of domains and may be modifiable/non-modifiable. Results will help decide most appropriate management and assist in planning and tailoring preoperative and postoperative rehabilitation.

METHODS AND ANALYSIS

This systematic review protocol is reported according to the Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols. MEDLINE, CINAHL and EMBASE databases, key journals and grey literature will be searched from inception to July 2019. Prospective cohort studies including participants aged ≥16 years who have undergone ACL reconstruction will be included, with articles focusing on multi-ligament reconstructions and ACL repair surgery, or not published in English excluded. Two independent reviewers will conduct searches, assess study eligibility, extract data, assess risk of bias (Quality in Prognostic Studies tool) and quantify overall quality of evidence (modified Grading of Recommendations, Assessment, Development and Evaluation guidelines). If possible, a meta-analysis will be conducted, otherwise a narrative synthesis will ensue focusing on prognostic factors, risk of bias of included studies and strength of association with outcomes.

ETHICS AND DISSEMINATION

Findings will be published in a peer-reviewed journal, presented at conferences and locally to physiotherapy departments. Ethical approval is not required for this systematic review.

PROSPERO REGISTRATION NUMBER

CRD42019127732.

Contralateral and siblings' knees are at higher risk of ACL tear for patients with a positive history of ACL tear

PURPOSE

Recent studies have shown that several genetic factors can cause susceptibility to anterior cruciate ligament (ACL) rupture. The aim of the present study was to evaluate certain underlying factors that increase the risk of ACL rupture.

METHODS

Eight hundred thirty-six patients with ACL rupture who underwent ACL reconstructive surgery from 2010 to 2013 at an academic center completed a minimum of 5 years post-operation follow-up. The collected variables included sex, age, height, weight, exercise level, time interval between ACL rupture in the first knee and contralateral ACL rupture, dominant leg, side of the involved knee and sibling history of ACL rupture.

RESULTS

The median follow-up duration was 6.5 (range: 5-8) years. Eighty-three patients (9.9%) had a contralateral ACL rupture, and 155 patients (18.5%) had siblings with a history of ACL rupture. The rate of contralateral ACL rupture was three times higher in women than in men and in patients with siblings with a history of ACL rupture than in those without such history. In addition, the risk of contralateral ACL rupture was higher in those younger than 30 years of age, those with a BMI of 20-25 kg/m² and those who participated in regular sports activity. However, whether the involved knee was on the dominant or nondominant side had no effect on the incidence of contralateral ACL rupture. The results of the study showed that 69 (83.1%) of the contralateral ACL ruptures occurred within the first 2 years after the primary operation.

CONCLUSION

In a 5- to 8-year follow-up, one out of every ten patients had a contralateral ACL rupture, and two out of every ten patients had siblings with a history of ACL rupture. The findings suggest that having a sibling with a history of ACL rupture and being female are important risk factors for ACL rupture of the contralateral knee.

LEVEL OF EVIDENCE

III.

A multi-chamber tissue culture device for load-dependent parallel evaluation of tendon explants

Background

Injuries in the musculoskeletal system, such as tendon and ligament ruptures, are challenging to manage and often require surgical reconstructions with limited long-term success. Thus, characterizations of these tissues are urgently needed to better understand cellular mechanisms that regulate tissue homeostasis and healing. Explant culturing systems allow for ex vivo analysis of tissues in an environment that mimics the native microenvironment in vivo.

Methods

Collaborative efforts within our institution facilitated the establishment of a novel explant culturing system. Tissue specimens cultured in single wells, with individual applied loading and/or biological environment, allowed characterization of tissue cultured under a variety of biological loading conditions. Quantitative PCR analysis for selected gene markers was our primary outcome.

Results

Data were stratified for analysis by either culture environment or loading condition. Our gene expression results show that specimens clustered by culture condition may differ in molecular markers related to ECM production (e.g., Col1a1, Adamts4) and/or organization (e.g., Tnc, Dnc). In contrast, loading condition did significantly alter the median gene expression levels of tissues in comparison to unloaded control samples, although gene expression values related to ECM degradation (e.g., Mmp1, Mmp10) were altered in tendons cultured under tension in the device.

Conclusion

Our study demonstrates promising utility of a novel explant culturing system for further characterization of musculoskeletal tissues such as native tendons and ligaments, as well as pathologic fibrotic tissues resulting from arthrofibrosis or Dupuytren’s disease.

Evidence-based recommendations for the management of anterior cruciate ligament (ACL) rupture

Anterior cruciate ligament (ACL) rupture occurs most commonly in young and active individuals and can have negative long-term physical and psychological impacts. The diagnosis is made with a combination of patient's history, clinical examination, and, if appropriate, magnetic resonance imaging. The objectives of management are to restore knee function, address psychological barriers to activity participation, prevent further injury and osteoarthritis, and optimize long-term quality of life. The three main treatment options for ACL rupture are (1) rehabilitation as first-line treatment (followed by ACL reconstruction (ACLR) in patients, who develop functional instability), (2) ACLR and post-operative rehabilitation as the first-line treatment, and (3) pre-operative rehabilitation followed by ACLR and post-operative rehabilitation. We provide practical recommendations for informing and discussing management options with patients, and describe patient-related factors associated with a worse ACL-rupture outcome. Finally, we define evidence-based rehabilitation and present phase-specific rehabilitation recommendations and criteria to inform return to sport decisions.

Towards prevention of post-traumatic osteoarthritis: report from an international expert working group on considerations for the design and conduct of interventional studies following acute knee injury

OBJECTIVE

There are few guidelines for clinical trials of interventions for prevention of post-traumatic osteoarthritis (PTOA), reflecting challenges in this area. An international multi-disciplinary expert group including patients was convened to generate points to consider for the design and conduct of interventional studies following acute knee injury.

DESIGN

An evidence review on acute knee injury interventional studies to prevent PTOA was presented to the group, alongside overviews of challenges in this area, including potential targets, biomarkers and imaging. Working groups considered pre-identified key areas: eligibility criteria and outcomes, biomarkers, injury definition and intervention timing including multi-modality interventions. Consensus agreement within the group on points to consider was generated and is reported here after iterative review by all contributors.

RESULTS

The evidence review identified 37 studies. Study duration and outcomes varied widely and 70% examined surgical interventions. Considerations were grouped into three areas: justification of inclusion criteria including the classification of injury and participant age (as people over 35 may have pre-existing OA); careful consideration in the selection and timing of outcomes or biomarkers; definition of the intervention(s)/comparator(s) and the appropriate time-window for intervention (considerations may be particular to intervention type). Areas for further research included demonstrating the utility of patient-reported outcomes, biomarkers and imaging outcomes from ancillary/cohort studies in this area, and development of surrogate clinical trial endpoints that shorten the duration of clinical trials and are acceptable to regulatory agencies.

CONCLUSIONS

These considerations represent the first international consensus on the conduct of interventional studies following acute knee joint trauma.

Natural corollaries and recovery after acute ACL injury: the NACOX cohort study protocol

INTRODUCTION

Anterior cruciate ligament (ACL) injury can result in joint instability, decreased functional performance, reduced physical activity and quality of life and an increased risk for post-traumatic osteoarthritis. Despite the development of new treatment techniques and extensive research, the complex and multifaceted nature of ACL injury and its consequences are yet to be fully understood. The overall aim of the NACOX study is to evaluate the natural corollaries and recovery after an ACL injury.

METHODS AND ANALYSIS

The NACOX study is a multicentre prospective prognostic cohort study of patients with acute ACL injury. At seven sites in Sweden, we will include patients aged 15-40 years, within 6 weeks after primary ACL injury. Patients will complete questionnaires at multiple occasions over the 3 years following injury or the 3 years following ACL reconstruction (for participants who have surgical treatment). In addition, a subgroup of 130 patients will be followed with clinical examinations, several imaging modalities and biological samples. Data analyses will be specific to each aim.

ETHICS AND DISSEMINATION

This study has been approved by the regional Ethical committee in Linköping, Sweden (Dnr 2016/44-31 and 2017/221-32). We plan to present the results at national and international conferences and in peer-reviewed scientific journals. Participants will receive a short summary of the results following completion of the study.

TRIAL REGISTRATION NUMBER

NCT02931084.

Effects of controlled abnormal joint movement on the molecular biological response in intra-articular tissues during the acute phase of anterior cruciate ligament injury in a rat model

Background

The anterior cruciate ligament (ACL) is responsible for braking forward movement of the tibia relative to the femur and for tibial rotation. After ACL injury, this braking performance deteriorates, inducing abnormal joint movement. The purpose of this study was to clarify the effects of controlled abnormal joint movement on the molecular biological response in intra-articular tissues during the acute phase of ACL injury.

Methods

Eighty-four mature Wistar male rats were randomly assigned to a controlled abnormal movement (CAM) group, an ACL-transection (ACL-T) group, a sham-operated group, or an intact group. The ACL was completely transected at its midportion in the ACL-T and CAM groups, and a nylon suture was used to control abnormal tibial translation in the CAM group. The sham-operated group underwent skin and joint capsule incisions and tibial drilling without ACL transection. Animals were not restricted activity until sacrifice 1, 3, or 5 days after surgery for histological and gene expression assessments. Acute-phase inflammation requires an important balance between degenerative and biosynthetic processes and is controlled by the activities of matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs). Both types of gene were analyzed in this study.

Results

The ACL-T and CAM groups exhibited cleavage of the ACL at all time points. However, for the CAM group, the gap in the ligament stump was extremely small, and fibroblast proliferation was observed around the stump. Relative to the ACL-T group, the CAM group demonstrated significantly lower expression of MMP-13 mRNA and a lower MMP-13/TIMP-1 ratio on days 1 and 5 in the ACL, the medial meniscus and the lateral meniscus. The expression of TIMP-1 mRNA was not significantly different between the ACL-T and CAM groups.

Conclusions

The study results suggested that controlling abnormal movement inhibited the inflammatory reaction in intra-articular tissues after ACL injury. This reaction was down-regulated in intra-articular tissues in the CAM group. Abnormal joint control caused prolonged inflammation and inhibited remodeling during the acute phase of ACL rupture.

Feasibility of Na18F PET/CT and MRI for Noninvasive In Vivo Quantification of Knee Pathophysiological Bone Metabolism in a Canine Model of Post-traumatic Osteoarthritis

Purpose:

To assess and quantify by molecular imaging knee osseous metabolic changes serially in an in vivo canine model of posttraumatic osteoarthritis (PTOA) of the knee utilizing sodium fluoride (Na¹⁸F) positron emission tomography (PET)/computed tomography (CT) coregistered with magnetic resonance imaging (MRI).

Materials and Methods:

Sodium fluoride PET imaging of 5 canines was performed prior to anterior cruciate ligament transection (ACLT) and 2 times post-ACLT (3 and 12 weeks). The PET/CT was coregistered with MRI, enabling serial anatomically guided visual and quantitative three-dimensional (3D) region of interest (ROI) assessment by maximum standardized uptake value.

Results:

Prior to ACLT, every 3D ROI assessed in both knees showed no Na¹⁸F uptake above background. The uptake of Na¹⁸F in the bone of the ACLT knees increased exponentially, presenting significantly higher uptake at 12 weeks in every region compared to the ACLT knees at baseline. Furthermore, the uninjured contralateral limb and the ipsilateral distal bones and joints presented Na¹⁸F uptake at 3 and 12 weeks post-ACLT.

Conclusion:

This study demonstrated that Na¹⁸F PET/CT coregistered with MRI is a feasible molecular imaging biomarker to assess knee osseous metabolic changes serially in an in vivo canine model of knee PTOA. Moreover, it brings a novel musculoskeletal preclinical imaging methodology that can provide unique insights into PTOA pathophysiology.

Traumatic knee injury: correlation of radiographic effusion size with the presence of internal derangement on magnetic resonance imaging

PURPOSE

Traumatic knee injury is a common clinical presentation. However, knee internal derangement often goes undiagnosed on physical exam. The authors hypothesize that patients with suprapatellar joint effusion greater than 10 mm anteroposterior diameter on lateral radiograph have a high likelihood of knee internal derangement on magnetic resonance imaging.

MATERIALS AND METHODS

A retrospective review of knee radiographs and magnetic resonance imaging in 198 patients age 18-40 years with acute knee injury was performed. Suprapatellar effusion diameter on lateral radiography was correlated to the presence of internal derangement on magnetic resonance imaging. Magnetic resonance imaging anteroposterior effusion size at four locations was correlated to radiographic suprapatellar effusion measurements.

RESULTS

Logistic regression showed a positive correlation between radiographic effusion size and the presence of internal derangement on magnetic resonance exams (p value < 0.001). Radiographic effusion > 10 mm was established as a positive test, yielding test sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of 55, 96, 93, 71, and 77%, respectively. Statistical analysis showed the radiographic anteroposterior effusion diameter most closely approximated the magnetic resonance effusion diameter at the lateral patellofemoral recess.

CONCLUSIONS

This study shows that knee radiography is a highly specific screening test for internal derangement in patients less than 40 years old with acute knee injury. In this patient population, knee effusion > 10 mm on lateral radiograph should prompt consideration for knee magnetic resonance examination. Adopting this approach as a clinical guideline has the potential to decrease delayed diagnosis, improve patient outcomes, and decrease cost-associated disability.

Self-reported functional recovery after reconstruction versus repair in acute anterior cruciate ligament rupture (ROTOR): a randomized controlled clinical trial

BACKGROUND

Anterior cruciate ligament (ACL) reconstruction is today's surgical gold standard for ACL rupture. Although it provides satisfactory results, not all patients return to their previous activity level and moreover, early posttraumatic osteoarthritis is not prevented. As such, a renewed interest has emerged in ACL suture repair combined with dynamic augmentation. Compared to ACL reconstruction, the hypothesized advantages of ACL suture repair are earlier return to sports, reduction of early posttraumatic osteoarthritis and preservation of the patient's native ACL tissue and proprioceptive envelope of the knee. In recent literature, ACL suture repair combined with dynamic augmentation tends to be at least equally effective compared to ACL reconstruction, but no randomized comparative study has yet been conducted.

METHODS/DESIGN

This study is a prospective, stratified, block randomized controlled trial. Forty-eight patients with an ACL rupture will be assigned to either a suture repair group with dynamic augmentation and microfracture of the femoral notch, or an ACL reconstruction group with autologous semitendinosis graft and all-inside technique. The primary objective is to investigate the hypothesis that suture repair of a ruptured ACL results in at least equal effectiveness compared with an ACL reconstruction in terms of patient self-reported outcomes (IKDC 2000 subjective scale) 1 year postoperatively. Secondary objectives are to evaluate patient self-reported outcomes (IKDC 2000, KOOS, Tegner, VAS), re-rupture rate, rehabilitation time required for return to daily and sports activities, achieved levels of sports activity, clinimetrics (Rolimeter, LSI, Isoforce) and development of osteoarthritis, at short term (6 weeks, 3, 6 and 9 months and 1 year), midterm (2 and 5 years) and long term (10 years) postoperatively.

DISCUSSION

A renewed interest has emerged in ACL suture repair combined with dynamic augmentation in the treatment of ACL rupture. Recent cohort studies show good short- and midterm results for this technique. This randomized controlled trial has been designed to compare the outcome of suture repair of a ruptured ACL, combined with DIS as well as microfracture of the femoral notch, with ACL reconstruction using autologous semitendinosus.

TRIAL REGISTRATION

Clinical Trials Register NCT02310854 (retrospectively registered on December 1st, 2014).

Nationwide study highlights a second peak in ACL tears for women in their early forties

PURPOSE

Anterior cruciate ligament (ACL) rupture continues to be a focus of research on knee injuries. Despite this, data on the total number of ruptures on a national basis including both reconstructed (ACLR) and non-reconstructed injuries are limited. The purpose of this study was to describe the national incidence of MRI diagnosed ACL ruptures in Iceland and its subsequent rate of operation with regard to sex and age.

METHODS

All MRI knee reports taken in Iceland between 2006 and 2011 were gathered to identify ACL ruptures. Software was written to search for phrases relating to ACL rupture. Duplicate records were removed and yearly incidence for sex and age groups was determined. Data from the Icelandic Social Insurance Administration were used identify all those who were operated and to determine the yearly incidence of ACLR. General additive models were used assuming either a Poisson or binomial distribution to model ACL rupture incidence and ACLR rate, respectively.

RESULTS

The average age was 33.9 (95% CI 33.1-34.6; Table 1). The average incidence of ACL tears per year was 75.1 (95% CI 71.3-79.1) per 100,000 person-years. For males the peak incidence was in their early twenties. Females showed two peaks, one in their teens and another in their forties resulting in an older average age at rupture compared to males (35 ± 16 vs 33 ± 13, p = 0.06). The main effects of age and sex and their interaction were significant (p < 0.001). The average incidence of ACLR was 39.4 (95% CI 36.7-42.4) per 100,000 person-years. Those operated were significantly younger than those who were not (27 ± 10 vs 42 ± 15 years, p < 0.001). The main effects of age and the interaction between sex and age were significant (p < 0.001).

CONCLUSION

This nationwide study indicates that ACL rupture incidence may be higher than previously thought, implying an underestimated impact of the burden of this serious knee injury. The incidence of injury peaked twice in the female population, a result not previously reported. Older persons are less likely to undergo ACLR and, therefore, sex-dependent differences in overall mean age at injury are contrary to previous reports. These data suggest that prevention programs focused solely on young girls should be extended to older women who are returning to sports.

LEVEL OF EVIDENCE

II.

Test-retest reliability of repeated knee laxity measurements in the acute phase following a knee trauma using a Rolimeter

The purpose was to examine the test-retest reliability of the Rolimeter measurement procedure in the acute time phase, following a substantial knee trauma. In total, 15 participants with acute knee trauma were examined by one single observer at three different time-points with the Rolimeter using a maximum force. The selected time-points were: baseline (0–7 days after the trauma), midpoint (3–4 weeks after the trauma), and endpoint (3–4 weeks after the trauma). The anterior-posterior displacement was recorded where the endpoint evaluation was used as the reference value. The mean anterior laxity scores remained constant over the measurement time-points for both knees, with an anterior laxity that was 2.7 mm higher (on average) in the injured than the noninjured knee (9.5 mm vs. 6.8 mm). The mean difference (i.e., bias) between laxity scores, for the injured knee, measured at endpoint versus baseline was 0.2±1.0 mm and −0.2±1.1 mm when measured at endpoint versus midpoint, with average typical errors of 0.7 and 0.8 mm and intra-class correlations that were very strong (both r=~0.93). For the same comparisons on the noninjured knee, systematic bias was close to zero (0.1±0.3 and −0.1±0.3 mm, respectively), and both the intra-class correlations were almost perfect (r=~0.99). The current study implicates that repeated Rolimeter measurements are relatively reliable for quantifying anterior knee laxity during the acute time-phases following knee trauma. Hence, the Rolimeter, in combination with manual tests, seems to be a valuable tool for identifying anterior cruciate ligament injuries.

Use of Robotic Manipulators to Study Diarthrodial Joint Function

Diarthrodial joint function is mediated by a complex interaction between bones, ligaments, capsules, articular cartilage, and muscles. To gain a better understanding of injury mechanisms and to improve surgical procedures, an improved understanding of the structure and function of diarthrodial joints needs to be obtained. Thus, robotic testing systems have been developed to measure the resulting kinematics of diarthrodial joints as well as the in situ forces in ligaments and their replacement grafts in response to external loading conditions. These six degrees-of-freedom (DOF) testing systems can be controlled in either position or force modes to simulate physiological loading conditions or clinical exams. Recent advances allow kinematic, in situ force, and strain data to be measured continuously throughout the range of joint motion using velocity-impedance control, and in vivo kinematic data to be reproduced on cadaveric specimens to determine in situ forces during physiologic motions. The principle of superposition can also be used to determine the in situ forces carried by capsular tissue in the longitudinal direction after separation from the rest of the capsule as well as the interaction forces with the surrounding tissue. Finally, robotic testing systems can be used to simulate soft tissue injury mechanisms, and computational models can be validated using the kinematic and force data to help predict in vivo stresses and strains present in these tissues. The goal of these analyses is to help improve surgical repair procedures and postoperative rehabilitation protocols. In the future, more information is needed regarding the complex in vivo loads applied to diarthrodial joints during clinical exams and activities of daily living to serve as input to the robotic testing systems. Improving the capability to accurately reproduce in vivo kinematics with robotic testing systems should also be examined.

Projecting Lifetime Risk of Symptomatic Knee Osteoarthritis and Total Knee Replacement in Individuals Sustaining a Complete Anterior Cruciate Ligament Tear in Early Adulthood

OBJECTIVE

To estimate the lifetime risk of knee osteoarthritis (OA) and total knee replacement (TKR) in persons sustaining anterior cruciate ligament (ACL) tear by age 25 years.

METHODS

We used the Osteoarthritis Policy Model to project the cumulative incidence of symptomatic knee OA requiring TKR in varying situations: no prevalent or incident injury; isolated ACL tear, surgically treated; isolated ACL tear, nonoperatively treated; or a prevalent history or surgically treated ACL and meniscal tear (MT). We estimated MT prevalence and incidence and increased risk of knee OA associated with ACL injury and MT from published literature. We conducted a range of sensitivity analyses to examine the impact of uncertainty in input parameters.

RESULTS

Estimated lifetime risk of symptomatic knee OA was 34% for the cohort with ACL injury and MT, compared to 14% for the no-injury cohort. ACL injury without MT was associated with a lifetime risk of knee OA between 16% and 17%, depending on ACL treatment modality. Estimated lifetime risk of TKR ranged from 6% in the no-injury cohort to 22% for the ACL injury and MT cohort. Subjects in the ACL injury and MT cohort developed OA approximately 1.5 years earlier (55.7 versus 57.1) and underwent TKR approximately 2 years earlier (66 versus 68) than the cohort without knee injuries.

CONCLUSION

Sustaining ACL injury early in adulthood leads to greater lifetime risk and earlier onset of knee OA and TKR; concomitant MTs compound this risk. These data provide insight into the impact of sustainable injury prevention interventions in young adults.

Risk factors for knee instability after anterior cruciate ligament reconstruction

PURPOSE

The objective of this study was to estimate risk factors that influence postoperative instability after anterior cruciate ligament (ACL) reconstruction using multivariate logistic regression analysis.

METHODS

A total of 152 consecutive patients with symptomatic ACL insufficiency underwent arthroscopic ACL reconstruction between 2005 and 2011. Loss to follow-up and previous ligament reconstruction were exclusion criteria, resulting in 131 patients remaining for this retrospective study. The median follow-up was 55 months (range 25-100 months). Patients were sorted into two groups by anterior translation on stress radiograph and pivot shift test grade and were analysed for the statistical significance of various risk factors including age at surgery, gender, body mass index, preoperative instability, time from injury to surgery, single-bundle reconstruction with preserved abundant remnant versus double-bundle reconstruction with scanty remnant, and concomitant ligament, meniscus, and articular cartilage injury with use of multivariate logistic regression analysis.

RESULTS

Time from injury to surgery over 12 weeks was found to be a significant risk factor for postoperative instability [p < 0.001, adjusted odds ratio (OR) 6.22; 95 % confidence interval (CI) 2.14-18.06)]. Grade 2 injury of medial collateral ligament (MCL) was also a risk factor (p = 0.02, adjusted OR 13.60; 95 % CI 1.24-148.25). The other variables were not found to be a significant risk factor.

CONCLUSIONS

Among the risk factor variables, concomitant grade 2 MCL injury and surgical delay of more than 12 weeks from injury were significant risk factors for postoperative knee instability after ACL reconstruction. The overall results suggest that surgery <12 weeks from injury and meticulous attention to concomitant MCL injury should be considered.

LEVEL OF EVIDENCE

Retrospective case-control study, Level III.

Effects of ACL Reconstructive Surgery on Temporal Variations of Cytokine Levels in Synovial Fluid

Anterior cruciate ligament (ACL) reconstruction restores knee stability but does not reduce the incidence of posttraumatic osteoarthritis induced by inflammatory cytokines. The aim of this research was to longitudinally measure IL-1β, IL-6, IL-8, IL-10, and TNF-α levels in patients subjected to ACL reconstruction using bone-patellar tendon-bone graft. Synovial fluid was collected within 24–72 hours of ACL rupture (acute), 1 month after injury immediately prior to surgery (presurgery), and 1 month thereafter (postsurgery). For comparison, a “control” group consisted of individuals presenting chronic ACL tears. Our results indicate that levels of IL-6, IL-8, and IL-10 vary significantly over time in reconstruction patients. In the acute phase, the levels of these cytokines in reconstruction patients were significantly greater than those in controls. In the presurgery phase, cytokine levels in reconstruction patients were reduced and comparable with those in controls. Finally, cytokine levels increased again with respect to control group in the postsurgery phase. The levels of IL-1β and TNF-α showed no temporal variation. Our data show that the history of an ACL injury, including trauma and reconstruction, has a significant impact on levels of IL-6, IL-8, and IL-10 in synovial fluid but does not affect levels of TNF-α and IL-1β.

Predictors for additional anterior cruciate ligament reconstruction: data from the Swedish national ACL register

PURPOSE

To identify predictors for additional anterior cruciate ligament (ACL) reconstruction.

METHODS

Patients from the Swedish national ACL register who underwent ACL reconstruction between January 2005 and February 2013 (follow-up duration 6-104 months) were included. Cox regression analyses included the following independent variables regarding primary injury: age, sex, time between injury and primary ACL reconstruction, activity at primary injury, concomitant injuries, injury side, graft type, and pre-surgery KOOS and EQ-5D scores.

RESULTS

Among ACL reconstruction procedures, 93% involved hamstring tendon (HT) autografts. Graft type did not predict additional ACL reconstruction. Final regression models only included patients with HT autograft (n = 20,824). Of these, 702 had revision and 591 contralateral ACL reconstructions. The 5-year post-operative rates of revision and contralateral ACL reconstruction were 4.3 and 3.8%, respectively. Significant predictors for additional ACL reconstruction were age (fourfold increased rate for <16-year-old patients vs. >35-year-old patients), time between injury and primary surgery (two to threefold increased rate for ACL reconstruction within 0-90 days vs. >365 days), and playing football at primary injury.

CONCLUSION

This study identified younger age, having ACL reconstruction early after the primary injury, and incurring the primary injury while playing football as the main predictors for revision and contralateral ACL reconstruction. This suggests that the rate of additional ACL reconstruction is increased in a selected group of young patients aiming to return to strenuous sports after primary surgery and should be taken into consideration when discussing primary ACL reconstruction, return to sports, and during post-surgery rehabilitation.

LEVEL OF EVIDENCE

II.

A conceptual framework for a sports knee injury performance profile (SKIPP) and return to activity criteria (RTAC)

Injuries to the knee, including intra-articular fractures, ligamentous ruptures, and meniscal and articular cartilage lesions, are commonplace within sports. Despite advancements in surgical techniques and enhanced rehabilitation, athletes returning to cutting, pivoting, and jumping sports after a knee injury are at greater risk of sustaining a second injury. The clinical utility of objective criteria presents a decision-making challenge to ensure athletes are fully rehabilitated and safe to return to sport. A system centered on specific indicators that can be used to develop a comprehensive profile to monitor rehabilitation progression and to establish return to activity criteria is recommended to clear athletes to begin a progressive and systematic approach to activities and sports. Integration of a sports knee injury performance profile with return to activity criteria can guide clinicians in facilitating an athlete's safe return to sport, prevention of subsequent injury, and life-long knee joint health.

New and emerging strategies in platelet-rich plasma application in musculoskeletal regenerative procedures: general overview on still open questions and outlook

Despite its pervasive use, the clinical efficacy of platelet-rich plasma (PRP) therapy and the different mechanisms of action have yet to be established. This overview of the literature is focused on the role of PRP in bone, tendon, cartilage, and ligament tissue regeneration considering basic science literature deriving from in vitro and in vivo studies. Although this work provides evidence that numerous preclinical studies published within the last 10 years showed promising results concerning the application of PRP, many key questions remain unanswered and controversial results have arisen. Additional preclinical studies are needed to define the dosing, timing, and frequency of PRP injections, different techniques for delivery and location of delivery, optimal physiologic conditions for injections, and the concomitant use of recombinant proteins, cytokines, additional growth factors, biological scaffolds, and stems cells to develop optimal treatment protocols that can effectively treat various musculoskeletal conditions.

What can the first 2 months tell us about outcomes after anterior cruciate ligament reconstruction?

CONTEXT

Substantial research has been conducted on anterior cruciate ligament reconstruction (ACLR) to evaluate patient outcomes. However, little attention has been given to outcomes during the early phase of recovery and how early deficits affect both short- and long-term outcomes.

OBJECTIVE

To identify relationships between demographic (age, sex, and body mass index [BMI]) and intraoperative (isolated ACLR versus primary ACLR + secondary procedures), and postoperative (range-of-motion [ROM] and peak isometric knee-extension force [PIF]) variables during the first 2 months after ACLR using self-reported outcomes.

DESIGN

Cohort study.

SETTING

Outpatient orthopaedic hospital.

PATIENTS OR OTHER PARTICIPANTS

A total of 63 patients (38 men, 25 women; age = 33.0 ± 12.1 years; BMI = 26.3 ± 6.5 kg/m(2)) who underwent ACLR.

MAIN OUTCOME MEASURE(S)

Demographic, intraoperative, and postoperative variables were collected at 1 and 2 months after ACLR and were compared with International Knee Documentation Committee (IKDC) Subjective Knee Evaluation Form scores at 1, 2, and ≥12 months.

RESULTS

Significant relationships were identified between ≥12-month IKDC scores and the 1-month (Pearson correlation, r = 0.283, r(2) = 0.08; P = .025) and 2-month (r = 0.301, r(2) = 0.09; P = .017) IKDC scores. After controlling for other variables, we found that the PIF ratio measures at 1 and 2 months were positively associated with 1- and 2-month IKDC scores (P < .001) and BMI was negatively associated with both 1- and 2-month IKDC scores (P < .05). One-month IKDC scores were related to the 1-month difference in knee-flexion ROM (P = .04).

CONCLUSIONS

The IKDC scores during the first 2 months were positively correlated with patients' perceptions of function on long-term IKDC scores. It also appears that improvements in lower extremity strength and flexion ROM deficits were positively associated with short-term IKDC scores. Higher BMI was negatively associated with patients' perceptions of function on short-term IKDC scores.

Does concomitant meniscectomy affect medium-term outcome of anterior cruciate ligament reconstruction? A preliminary report

INTRODUCTION

Anterior cruciate ligament (ACL) injury is often accompanied by injuries of the menisci. In order to restore knee stability, anterior cruciate ligament reconstruction (ACLR) is performed, with meniscus surgery when needed. The purpose of this study was to assess the medium-term outcome of ACLR in subjects with and without concomitant meniscus tear and partial meniscectomy.

MATERIAL AND METHODS

We prospectively studied 73 patients after arthroscopically assisted bone-patellar tendon-bone ACLR. Subjects were divided into two subgroups: those who had only ACLR (group A, 54 subjects with mean age 28, (SD 9)) and those who underwent both ACLR and concomitant partial meniscectomy (group B, 19 subjects, mean age 32 [11]). Subjects completed a disease-specific questionnaire, the Knee injury and Osteoarthritis Outcome Score (KOOS), preoperatively and at a minimum follow-up of 1 year.

RESULTS

No differences in mean scores between group A and B were observed either preoperatively or at follow-up. We found a significant change in mean score in the KOOS subscale QoL in group A following ACLR (Δ = 9 points, p = 0.039). Most subjects improved in the KOOS subscales Sports and Recreation and QoL in both group A (59 and 52% respectively) and B (63 and 47% respectively). Eight subjects (15%) from group A and 1 (5%) from group B fulfilled criteria of functional recovery. Criteria of treatment failure were fulfilled in 17 subjects (32%) from A and 4 (21%) from group B.

CONCLUSIONS

Patients undergoing ACLR with partial meniscectomy had a similar medium-term outcome compared to individuals with ACL tear alone.

Population-wide incidence estimates for soft tissue knee injuries presenting to healthcare in southern Sweden: data from the Skåne Healthcare Register

Introduction

Soft tissue knee injury is a well-established and potent risk factor for development of knee osteoarthritis. However, there is a paucity of epidemiological data from the general population. Our aim was to estimate the annual person-level incidence for a wide spectrum of clinically diagnosed soft tissue knee injuries, and their distribution by age, sex, and season.

Methods

In Sweden, in- and outpatient health care is registered using each individuals’ unique personal identifier including International Classification of Diseases (ICD) 10 diagnostic code(s) as determined by physicians’ clinical examination. For the calendar years 2004–2012, we studied the population in southern Sweden, Skåne region (approx. 1.3 million). We identified residents who had at least one visit to a physician with clinically diagnosed knee ligament, meniscal, or other soft-tissue injury (S80.0, S83 and all subdiagnoses). We then calculated the mean annual incidence over the 9-year period. As a secondary objective, we investigated potential seasonal variation.

Results

The annual incidence for males and females was 766 (95% CI: 742, 789) and 676 (649, 702) per 100,000 persons/year respectively. For males and females, the peak rate occurred in 15 to 19 year-olds (1698 per 100,000 men and 1464 per 100,000 women, respectively). In women, rates were lowest in the 25 to 34 year-old age range before rising again between the ages of 35 and 49 years. We found substantial seasonal variation, greatest in men, with peaks in March-May and August-October.

Conclusions

The incidence of clinically diagnosed soft-tissue knee injury peaks in adolescence and emerging adulthood. However, a range of knee injuries continue to occur across the adult lifespan including at ages when osteoarthritis is typically diagnosed and managed. The potential cumulative effect on osteoarthritis progression of these injuries may warrant further investigation.

Electronic supplementary material

The online version of this article (doi:10.1186/ar4678) contains supplementary material, which is available to authorized users.

Biology of anterior cruciate ligament injury and repair: Kappa delta ann doner vaughn award paper 2013

Anterior cruciate ligament (ACL) injuries are currently treated by removing the injured ligament and replacing it with a tendon graft. Recent studies have examined alternative treatment methods, including repair and regeneration of the injured ligament. In order to make such an approach feasible, a basic understanding of ACL biology and its response to injury is needed. Identification of obstacles to native ACL healing can then be identified and potentially resolved using tissue engineering strategies-first, with in vitro screening assays, and then with in vivo models of efficacy and safety. This Perspectives paper outlines this path of discovery for optimizing ACL healing using a bio-enhanced repair technique. This journey required constructing indices of the functional tissue response, pioneering physiologically based methods of biomechanical testing, developing, and validating clinically relevant animal models, and creating and optimizing translationally feasible scaffolds, surgical techniques, and biologic additives. Using this systematic translational approach, "bio-enhanced" ACL repair has been advanced to the point where it may become an option for future treatment of acute ACL injuries and the prevention of subsequent post-traumatic osteoarthritis associated with this injury.

Post-traumatic osteoarthritis: from mouse models to clinical trials

Osteoarthritis (OA), the most common of all arthropathies, is a leading cause of disability and has a large (and growing) worldwide socioeconomic cost. Despite its burgeoning importance, translation of disease-modifying OA therapies from the laboratory into clinical practice has slowed. Differences between the OA models studied preclinically and the disease evaluated in human clinical trials contribute to this failure. Most animal models of OA induce disease through surgical or mechanical disruption of joint biomechanics in young individuals rather than the spontaneous development of age-associated disease. This instability-induced joint disease in animals best models the arthritis that develops in humans after an injurious event, known as post-traumatic OA (PTOA). Studies in genetically modified mice suggest that PTOA has a distinct molecular pathophysiology compared with that of spontaneous OA, which might explain the poor translation from preclinical to clinical OA therapeutic trials. This Review summarizes the latest data on potential molecular targets for PTOA prevention and modification derived from studies in genetically modified mice, and describes their validation in preclinical therapeutic trials. This article focuses on how these findings might best be translated to humans, and identifies the potential challenges to successful implementation of clinical trials of disease-modifying drugs for PTOA.

Evaluating rotational kinematics of the knee in ACL reconstructed patients using 3.0 Tesla magnetic resonance imaging

INTRODUCTION

Injury to the anterior cruciate ligament (ACL) is common. While prior studies have shown that surgical reconstruction of the ACL can restore anterior-posterior kinematics, ACL-injured and reconstructed knees have been shown to have significant differences in tibial rotation when compared to uninjured knees. Our laboratory has developed an MR compatible rotational loading device to objectively quantify rotational stability of the knee following ACL injuries and reconstructions. Previous work from our group demonstrated a significant increase in total tibial rotation following ACL injuries. The current study is a prospective study on the same cohort of patients who have now undergone ACL reconstruction. We hypothesize that ACL reconstructed knees will have less tibial rotation relative to the pre-operative ACL deficient condition. We also hypothesize that ACL reconstructed knees will have greater rotational laxity when compared to healthy contralateral knees.

METHODS

Patients. Six of the ACL injured patients from our initial study who had subsequently undergone ACL reconstruction were evaluated 8.1 ± 2.9 months after surgery. All patients underwent single-bundle ACL reconstruction using anteromedial portal drilling of the femoral tunnel with identical post-operative regimens. Magnetic Resonance (MR) Imaging. Patients were placed in a supine position in the MR scanner on a custom-built loading device. Once secured in the scanner bore, an internal/external torque was applied to the foot. The tibiae were semi-automatically segmented with in-house software. Tibial rotation comparisons were made within subjects (i.e. side-to-side comparison between reconstructed and contralateral knees) and differences were explored using paired sample t-tests with significance set at p=0.05.

RESULTS

Regarding tibial rotation, in the ACL deficient state, these patients experienced an average of 5.9 ± 4.1° difference in tibial rotation between their ACL deficient and contralateral knees. However, there was a -0.2 ± 6.1° difference in tibial rotation of the ACL reconstructed knee when compared to the contralateral uninjured knee. Regarding tibial translation, ACL deficient patients showed a difference of 0.75 ± 1.4mm of anterior tibial translation between injured and healthy knees. After ACL reconstruction, there was a 0.2 ± 1.1mm difference in coupled anterior tibial translation of the ACL reconstructed knee compared to the contralateral knee. No significant differences in contact area between the two time points could be discerned.

DISCUSSION

The objective of our study was to assess the rotational laxity present in ACL reconstructed knees using a previously validated MRI-compatible rotational loading device. Our study demonstrated that ACL reconstruction can restore rotational laxity under load. This may speak to the benefit of an anteromedial drilling technique, which allows for a more horizontal and anatomically appropriate graft position.

Abnormal tibiofemoral kinematics following ACL reconstruction are associated with early cartilage matrix degeneration measured by MRI T1rho

PURPOSE

Altered kinematics following ACL-reconstruction may be a cause of post-traumatic osteoarthritis. T(1ρ) MRI is a technique that detects early cartilage matrix degeneration. Our study aimed to evaluate kinematics following ACL-reconstruction, cartilage health (using T(1ρ) MRI), and assess whether altered kinematics following ACL-reconstruction are associated with early cartilage degeneration.

METHODS

Eleven patients (average age: 33 ± 9 years) underwent 3T MRI 18 ± 5 months following ACL-reconstruction. Images were obtained at extension and 30° flexion under simulated loading (125 N). Tibial rotation (TR) and anterior tibial translation (ATT) between flexion and extension, and T(1ρ) relaxation times of the knee cartilage were analyzed. Cartilage was divided into five compartments: medial and lateral femoral condyles (MFC/LFC), medial and lateral tibias (MT/LT), and patella. A sub-analysis of the femoral weight-bearing (wb) regions was also performed. Patients were categorized as having "abnormal" or "restored" ATT and TR, and T(1ρ) percentage increase was compared between these two groups of patients.

RESULTS

As a group, there were no significant differences between ACL-reconstructed and contralateral knee kinematics, however, there were individual variations. T(1ρ) relaxation times of the MFC and MFC-wb region were elevated (p ≤ 0.05) in the ACL-reconstructed knees compared to the uninjured contralateral knees. There were increases (p ≤ 0.05) in the MFC-wb, MT, patella and overall average cartilage T(1ρ) values of the "abnormal" ATT group compared to "restored" ATT group. The percentage increase in the T(1ρ) relaxation time in the MFC-wb cartilage approached significance (p=0.08) in the "abnormal" versus "restored" TR patients.

CONCLUSIONS

Abnormal kinematics following ACL-reconstruction appear to lead to cartilage degeneration, particularly in the medial compartment.

Evaluating rotational kinematics of the knee in ACL-ruptured and healthy patients using 3.0 Tesla magnetic resonance imaging

PURPOSE

Rotational knee laxity is an important measure in restoring knee stability following anterior cruciate ligament (ACL) injury, but is difficult to quantify with current clinical tools. The hypothesis of the study is that there is greater tibial rotation (TR) in women than men, and also in ACL-deficient than healthy knees.

METHODS

Sixteen healthy (8 men, 26.8 ± 6.4 years; 8 women, 26.9 ± 3.8 years) and ten ACL-deficient (5 men, 33.6 ± 10.5 years; 5 women, 36.3 ± 10.7 years) subjects received bilateral knee MRI in 15° of flexion using a custom device to apply a constant axial compressive load (44 N). A rotational torque (3.35 Nm) was sequentially applied to obtain images at internal and external rotation positions. T (2)-weighted images were acquired in internal and external rotation. Images were segmented and TR was calculated. To assess reproducibility, six knees were scanned twice on separate days. Group comparisons were made with unpaired t tests, while intrasubject comparisons were made using paired t tests.

RESULTS

Healthy women demonstrated greater TR than men (13.6° ± 4.7° vs. 8.3° ± 3.6°; P = 0.001). Male ACL-deficient knees showed greater TR than the contralateral knee (15.7° ± 6.9° vs. 7.7° ± 5.6°; P = 0.003), and compared to male controls (P = 0.002). ACL-deficient women showed greater TR compared to their contralateral leg (15.1° ± 2.3° vs. 10.0° ± 4.3°; P = 0.01). The intraclass correlation coefficient of the TR measurement was 0.913, and the SEM = 1.1°.

CONCLUSIONS

Kinematic MRI is a reproducible method to quantify total knee rotation. Women have more rotational laxity than men, particularly in the external rotation position. ACL rupture leads to increased rotational laxity of the knee.

LEVEL OF EVIDENCE

Retrospective case-control series, Level III.

Biomechanical considerations in the pathogenesis of osteoarthritis of the knee

Osteoarthritis is the most common joint disease and a major cause of disability. The knee is the large joint most affected. While chronological age is the single most important risk factor of osteoarthritis, the pathogenesis of knee osteoarthritis in the young patient is predominantly related to an unfavorable biomechanical environment at the joint. This results in mechanical demand that exceeds the ability of a joint to repair and maintain itself, predisposing the articular cartilage to premature degeneration. This review examines the available basic science, preclinical and clinical evidence regarding several such unfavorable biomechanical conditions about the knee: malalignment, loss of meniscal tissue, cartilage defects and joint instability or laxity. Level of evidence IV.

Pattern of joint damage in persons with knee osteoarthritis and concomitant ACL tears

Anterior cruciate ligament (ACL) tears are known to be a risk factor for incident knee osteoarthritis (OA). At the present time, it is unknown whether an incidental ACL tear in those with established knee OA alters the pattern of synovial joint damage. Therefore, our aim was to assess whether ACL tears in persons with knee OA are associated with specific patterns of cartilage loss, meniscal degeneration, and bone marrow lesion (BML) location. We included 160 participants from the progression subcohort of the Osteoarthritis Initiative (OAI) Study, an ongoing 4-year, multicenter study, focusing on knee OA. Regional cartilage morphometry measures including cartilage volume (mm(3)), denuded area, normalized cartilage volume, bone surface area, as well as location of meniscal pathology and BMLs in index knees on the same side were compared between those with and without ACL tears. Of the 160 subjects (51% women, age 62.1 (±9.9), BMI 30.3 (±4.7) kg/m(2)), 14.4% had an ACL tear. After adjusting for age, BMI and gender participants with ACL tears had significantly greater cartilage volume in the posterior lateral femur (P = 0.04) and the central medial tibia (0.001) compared to those without ACL tears. Normalized cartilage volume was not different between those with and without ACL tears. In addition, individuals with ACL tears had significantly larger bone surface areas in the medial tibia (P = 0,006), the central medial tibia (P = 0.008), the posterior lateral femur (P = 0.004), and the posterior medial femur (P = 0.04). Furthermore, participants with ACL tears showed significantly more meniscal derangement in the lateral posterior horn (P = 0.019) and significantly more BMLs in the lateral femur (P = 0.0025). We found clear evidence of predominant lateral tibiofemoral involvement, with OA-associated findings on MRI, including increased denuded area and bone surface area, BMLs, and meniscal derangement in knees of individuals with ACL tears compared to those without.

Anterior cruciate ligament injury in elite football: a prospective three-cohort study

Anterior cruciate ligament (ACL) injury causes long lay-off time and is often complicated with subsequent new knee injury and osteoarthritis. Female gender is associated with an increased ACL injury risk, but few studies have adjusted for gender-related differences in age although female players are often younger when sustaining their ACL injury. The objective of this three-cohort study was to describe ACL injury characteristics in teams from the Swedish men's and women's first leagues and from several European men's professional first leagues. Over a varying number of seasons from 2001 to 2009, 57 clubs (2,329 players) were followed prospectively and during this period 78 ACL injuries occurred (five partial). Mean age at ACL injury was lower in women compared to men (20.6 ± 2.2 vs. 25.2 ± 4.5 years, P = 0.0002). Using a Cox regression, the female-to-male hazard ratio (HR) was 2.6 (95% CI 1.4-4.6) in all three cohorts studied and 2.6 (95% CI 1.3-5.3) in the Swedish cohorts; adjusted for age, the HR was reduced to 2.4 (95% CI 1.3-4.2) and 2.1 (95% CI 1.0-4.2), respectively. Match play was associated with a higher ACL injury risk with a match-to-training ratio of 20.8 (95% CI 12.4-34.8) and 45 ACL injuries (58%) occurred due to non-contact mechanisms. Hamstrings grafts were used more often in Sweden than in Europe (67 vs. 34%, P = 0.028), and there were no differences in time to return to play after ACL reconstruction between the cohorts or different grafts. In conclusion, this study showed that the ACL injury incidence in female elite footballers was more than doubled compared to their male counterparts, but also that they were significantly younger at ACL injury than males. These findings suggest that future preventive research primarily should address the young female football player.

New developments in osteoarthritis. Prevention of injury-related knee osteoarthritis: opportunities for the primary and secondary prevention of knee osteoarthritis

Where risk factors have been identified in knee and hip osteoarthritis (OA), with few exceptions, no prevention strategies have proven beneficial. The major risk factors for knee OA are advanced age, injury and obesity. However, there is limited or no evidence that they are modifiable or to what degree modifying them is effective in preventing development of knee OA or in preventing symptoms and progressive disease in persons with early OA. The notable exception is the growing epidemic of (sports) injury related knee OA. This review details the biological and clinical data indicating the efficacy of interventions targeting neuromuscular and biomechanical factors that make this subset of OA an attractive public health target, and highlights research opportunities for the future.

[Diagnostic approaches to acute knee injury in childhood and adolescence. Yesterday and today]

INTRODUCTION

Clinical examination of acute knee injury in childhood is often difficult and therefore magnetic resonance imaging (MRI) serves as an additional diagnostic tool. The aim of the present study was to evaluate on the one hand the indications for diagnostic arthroscopy and on the other hand the indications for MRI.

METHODS

Of the children treated between 1990 and 1999, 87 (group 1) underwent arthroscopy after clinical examination. Between 2000 and 2006 (group 2) 83 patients were examined using MRI after clinical examination and 53 were subsequently submitted to arthroscopy.

RESULTS

In group 1 the clinical diagnosis was verified by arthroscopy in 79%. In group 2 the clinical and arthroscopic diagnoses were consistent in 60% of the patients. The MRI diagnosis was correctly recognized for patella dislocation in all cases, for ligament injuries in 83% and for meniscus injuries in 56%. Due to the application of MRI before arthroscopy the fraction of diagnostic arthroscopies could be reduced from 22% to 13%.

CONCLUSION

The number of diagnostic arthroscopies in childhood can be reduced by application of MRI.

Knee stability assessment on anterior cruciate ligament injury: Clinical and biomechanical approaches

Anterior cruciate ligament (ACL) injury is common in knee joint accounting for 40% of sports injury. ACL injury leads to knee instability, therefore, understanding knee stability assessments would be useful for diagnosis of ACL injury, comparison between operation treatments and establishing return-to-sport standard. This article firstly introduces a management model for ACL injury and the contribution of knee stability assessment to the corresponding stages of the model. Secondly, standard clinical examination, intra-operative stability measurement and motion analysis for functional assessment are reviewed. Orthopaedic surgeons and scientists with related background are encouraged to understand knee biomechanics and stability assessment for ACL injury patients.

Outcome and knee-related quality of life after anterior cruciate ligament reconstruction: a long-term follow-up

The aim of the present investigation was to study patient-reported long-term outcome after anterior cruciate ligament (ACL) reconstruction. On an average 11.5 years after ACL reconstruction with bone-patellar tendon-bone (BPTB) autograft 56 patients were asked to answer four different questionnaires about their knee function and knee-related quality of life. Another aim was to study whether there were any correlations between clinical tests, commonly used for evaluating patients with ACL injuries, which were performed 2 years after ACL reconstruction, and patient-reported outcome in terms of knee function and knee-related quality of life on an average 9.5 years later. All patients who had unilateral BPTB ACL reconstructions were examined at 2 years and on an average 11.5 years after surgery. At 2 years one-leg hop test for distance, isokinetic muscle torque measurement, sagittal knee laxity, Lysholm knee scoring scale and Tegner activity scale were used for clinical evaluation. At the follow-up on an average 9.5 years later the patients were evaluated with knee injury osteoarthritis outcome score (KOOS), short form health survey (SF 36), Lysholm knee scoring scale and Tegner activity scale. The SF-36 showed that the patients had a similar health condition as an age- and gender-matched normal population in Sweden on an average 11.5 years after ACL reconstruction. There was no correlation between the results of one-leg hop test for distance, isokinetic muscle torque measurement, sagittal knee laxity evaluated 2 years after surgery and the result of KOOS (function in sport and recreation, knee-related quality of life) and SF-36 evaluated on an average 11.5 years after surgery. We also compared patients that 2 years after surgery demonstrated a side-to-side difference in anterior-posterior knee laxity of more than 3 mm with those with 3 mm or less and found no significant group differences in terms of knee function as determined with KOOS. We found no correlation between the results of KOOS and SF-36 at the long-term follow-up and the time between injury and surgery, age at surgery or gender, respectively. We conclude that there is no correlation between patient-reported knee function in sport and recreation and knee-related quality of life on an average 11.5 years after BPTP ACL reconstruction and the evaluation methods used 2 years after surgery.

Prediction of patient-reported outcome after single-bundle anterior cruciate ligament reconstruction

PURPOSE

The purpose of this study was to identify preoperative and intraoperative factors that predict patient-oriented outcome as measured by the International Knee Documentation Committee (IKDC) Subjective Knee Form after anterior cruciate ligament (ACL) reconstruction.

METHODS

We identified 402 subjects who had undergone primary single-bundle arthroscopic ACL reconstruction at a mean follow-up of 6.3 years (range, 2 to 15 years). The IKDC Subjective Knee Form was used to measure patient-reported outcome and was dichotomized as above or below the patient-specific age- and gender-matched population mean. Potential predictor variables included subject demographics, activity level before surgery, previous meniscectomy, and surgical variables. Multivariate logistic regression analysis was performed to identify the best subset of predictors for determining the likelihood that the IKDC score was better than the age- and gender-matched population mean.

RESULTS

The dichotomized IKDC score was associated with body mass index (BMI), smoking status, education, previous medial meniscectomy, and medial chondrosis at the time of ACL reconstruction. The multivariate model containing only factors known before surgery included BMI and smoking status. Subjects with a BMI greater than 30 kg/m(2) had 0.35 times the odds of success as subjects with a normal BMI. Subjects who smoked had 0.36 times the odds of success as subjects who did not smoke. A model including medial chondrosis at the time of surgery had a slightly higher discriminatory power (area under the receiver operating characteristic curve, 0.65 v 0.61) and negative predictive value (71.4% v 60.0%) but similar positive predictive power (86.3% v 85.9%).

CONCLUSIONS

Lower patient-reported outcome after ACL reconstruction was strongly associated with obesity, smoking, and severe chondrosis at the time of surgery.

LEVEL OF EVIDENCE

Level III, prognostic case-control study.

Non-contact ACL injuries in female athletes: an International Olympic Committee current concepts statement

The incidence of anterior cruciate ligament (ACL) injury remains high in young athletes. Because female athletes have a much higher incidence of ACL injuries in sports such as basketball and team handball than male athletes, the IOC Medical Commission invited a multidisciplinary group of ACL expert clinicians and scientists to (1) review current evidence including data from the new Scandinavian ACL registries; (2) critically evaluate high-quality studies of injury mechanics; (3) consider the key elements of successful prevention programmes; (4) summarise clinical management including surgery and conservative management; and (5) identify areas for further research. Risk factors for female athletes suffering ACL injury include: (1) being in the preovulatory phase of the menstrual cycle compared with the postovulatory phase; (2) having decreased intercondylar notch width on plain radiography; and (3) developing increased knee abduction moment (a valgus intersegmental torque) during impact on landing. Well-designed injury prevention programmes reduce the risk of ACL for athletes, particularly women. These programmes attempt to alter dynamic loading of the tibiofemoral joint through neuromuscular and proprioceptive training. They emphasise proper landing and cutting techniques. This includes landing softly on the forefoot and rolling back to the rearfoot, engaging knee and hip flexion and, where possible, landing on two feet. Players are trained to avoid excessive dynamic valgus of the knee and to focus on the "knee over toe position" when cutting.

The challenge of recruiting patients with anterior cruciate ligament injury of the knee into a randomized clinical trial comparing surgical and non-surgical treatment

AIMS

To determine the number of patients needed to be screened (NNS) and allocated (NNA) in order to include one participant in a randomized clinical trial (RCT), and to compare the characteristics of patients accepting or declining participation in the RCT.

METHODS

The recruitment process of an ongoing multicenter RCT, comparing surgical and non-surgical interventions after acute anterior cruciate ligament (ACL) injury of the knee is described. We use the known concept Number Needed to Screen (NNS) and introduce the new concept Number Needed to Allocate (NNA) as variables to support a priori sample size calculations of future investigations.

RESULTS

560 patients were screened to identify 162 patients (29%) eligible for inclusion in the RCT. 41 of those declined participation for various reasons, the most common being unwillingness to undergo surgery (n=23) or unwillingness to risk conservative treatment (n=8). 19 patients were excluded after MRI assessment or arthroscopy. Thus, 102 (18%) patients were allocated to one of the two treatments in the RCT. The NNS was 5.5 individuals with an acute knee injury, and the NNA was 1.6 individuals eligible for inclusion, to include 1 patient in the RCT. Patients declining to participate in the RCT were more frequently self-employed and less frequently injured in sports activities than those accepting RCT participation.

CONCLUSIONS

We suggest that the a priori sample size calculation needs to be multiplied by at least 5.5 to provide an estimate of the number needed to screen, or 1.6 to provide an estimate of the number needed to allocate in order to include the desired number of patients in a trial comparing surgical and non-surgical treatment of the ACL injured patient.