Cartilage adaptation after anterior cruciate ligament injury and reconstruction: implications for clinical management and research? A systematic review of longitudinal MRI studies

Lifetime risk and genetic predisposition to post-traumatic OA of the knee in the UK Biobank

OBJECTIVE

Acute knee injury is associated with post-traumatic OA (PTOA). Very little is known about the genome-wide associations of PTOA when compared with idiopathic OA (iOA). Our objective was to describe the development of knee OA after a knee injury and its genetic associations in UK Biobank (UKB).

DESIGN

Clinically significant structural knee injuries in those ≤50 years were identified from electronic health records and self-reported data in 502,409 UKB participants. Time-to-first knee osteoarthritis (OA) code was compared in injured cases and age-/sex-matched non-injured controls using Cox Proportional Hazards models. A time-to-OA genome-wide association study (GWAS) sought evidence for PTOA risk variants 6 months to 20 years following injury. Evidence for associations of two iOA polygenic risk scores (PRS) was sought.

RESULTS

Of 4233 knee injury cases, 1896 (44.8%) were female (mean age at injury 34.1 years [SD 10.4]). Over a median of 30.2 (IQR 19.5-45.4) years, 1096 (25.9%) of injured cases developed knee OA. The overall hazards ratio (HR) for knee OA after injury was 1.81 (1.70,1.93), P = 8.9 × 10-74. Female sex and increasing age at injury were associated with knee OA following injury (HR 1.15 [1.02,1.30];1.07 [1,07,1.07] respectively). OA risk was highest in the first 5 years after injury (HR 3.26 [2.67,3.98]), persisting for 40 years. In 3074 knee injury cases included in the time-to-OA GWAS, no variants reached genome-wide significance. iOA PRS was not associated with time-to-OA (HR 0.43 [0.02,8.41]).

CONCLUSIONS

Increasing age at injury and female sex appear to be associated with future development of PTOA in UKB, the risk of which was greatest in the 5 years after injury. Further international efforts towards a better-powered meta-analysis will definitively elucidate genetic similarities and differences of PTOA and iOA.

Knee MRI biomarkers associated with structural, functional and symptomatic changes at least a year from ACL injury - A systematic review

Introduction

Osteoarthritis (OA) results from various aetiologies, including joint morphology, biomechanics, inflammation, and injury. The latter is implicated in post-traumatic OA, which offers a paradigm to identify potential biomarkers enabling early identification and intervention. This review aims to describe imaging features associated with structural changes or symptoms at least one year following injury.

Methodology

A systematic review was conducted using PRISMA guidance, prospectively registered on PROSPERO (CRD42022371838). Three independent reviewers screened titles and abstracts, followed by full-texts, performed data extraction, and risk of bias assessments (Newcastle-Ottawa Scale). Inclusion criteria included imaging studies involving human participants aged 18-45 who had sustained a significant knee injury at least a year previously. A narrative synthesis was performed using synthesis without meta-analysis methodology.

Results

Six electronic databases and conference proceedings were searched, identifying 11 studies involving 776 participants. All studies included participants suffering an anterior cruciate ligament (ACL) injury and utilised MRI. Different, and not directly comparable, techniques were used. MRI features could be broadly divided into structural, including joint position and morphology, and compositional. Promising biomarkers for diagnosing and predicting osteoarthritis include T1rho and T2 relaxation time techniques, bone morphology changes and radiomic modelling.

Discussion

As early as 12 months after injury, differences in tibia position, bone morphology, presence of effusion and synovitis, and cartilage/subchondral bone composition can be detected, some of which are linked with worse patient-reported or radiological progression. Standardisation, including MR strength, position, sequence, scoring and comparators, is required to utilise clinical and research OA imaging biomarkers fully.

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

Background

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

Methods

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

Results

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

Conclusions

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

Supplementary Information

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

Kinetic changes associated with extended knee landings following anterior cruciate ligament reconstruction in females

OBJECTIVES

To determine the relationship between knee flexion excursion symmetry and lower extremity kinematics, kinetics, and muscle, joint, and ligament forces in females 1-3 years after ACL reconstruction.

DESIGN

Cross-sectional.

SETTING

Laboratory.

PARTICIPANTS

Twenty-one, college-aged females.

MAIN OUTCOME MEASURES

Lower extremity kinetics and kinematics, including estimated muscle, tibiofemoral, and ligament forces were assessed using 3D motion analysis and a musculoskeletal modeling approach. Participants demonstrating greater than 10% asymmetry in knee flexion excursion were classified as landing with an "extended knee". Group and between-limb differences were compared.

RESULTS

Ten participants were classified as landing with an "extended knee" on the involved limb, while eleven exhibited a symmetric landing pattern. Participants landing with an "extended knee" demonstrated reduced knee extension moment and quadriceps force in the involved limb (p < 0.05).

CONCLUSIONS

These findings indicate that an "extended knee" landing pattern was associated with reduced knee extension moment and quadriceps muscle force in females 1-3 years after ACL reconstruction. This may represent an altered strategy that clinicians may choose to identify and address during rehabilitation.

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

INTRODUCTION

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

MATERIAL AND METHODS

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

RESULTS

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

CONCLUSION

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

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

BACKGROUND

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

PURPOSE

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

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

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

RESULTS

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

CONCLUSION

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

Development of MRI-defined Structural Tissue Damage after Anterior Cruciate Ligament Injury over 5 Years: The KANON Study

Background MRI is used to evaluate structural joint changes after anterior cruciate ligament (ACL) injury, but no long-term data are available for comparing different treatment approaches. Purpose To describe structural joint damage with MRI over a 5-year period in the Knee Anterior Cruciate Ligament, Nonsurgical versus Surgical Treatment (KANON) study and to compare frequencies of such tissue damage for a nonsurgical versus a surgical treatment strategy. Materials and Methods In this secondary analysis of a prospective trial (ISRCTN 84752559), 119 participants with an acute ACL injury were evaluated. Participants were enrolled from 2002 through 2006, the 2-year follow-up started in 2008, and the 5-year follow-up started in 2011. A 1.5-T MRI examination was performed at baseline and at 2- and 5-year follow-up. MRI scans were read according to a validated scoring instrument. Kruskal-Wallis tests were used to assess whether the frequencies of structural damage differed between the three as-treated groups. Results Of 119 participants (mean age, 26 years ± 5 [standard deviation]), 91 men were evaluated. At 2- and 5-year follow-up, respectively, 13% (15 of 117) and 13% (15 of 115) of knees showed incident cartilage damage in the medial tibiofemoral joint, 11% (13 of 117) and 17% (20 of 115) of knees showed incident cartilage damage in the lateral tibiofemoral joint, and 4% (five of 117) and 8% (nine of 115) of knees showed incident cartilage damage in the patellofemoral joint. Osteophyte development was seen in 23% (27 of 117) and 29% (33 of 115) of knees in the medial tibiofemoral joint, in 36% (42 of 117) and 43% (49 of 115) of knees in the lateral tibiofemoral joint, and in 35% (41 of 117) and 37% (42 of 115) of knees in the patellofemoral joint. No major differences between the groups were found for incident or worsening cartilage damage, bone marrow lesions, and osteophytes at 2 or 5 years. The rehabilitation-alone group showed less Hoffa-synovitis at 2 (P = .02) and 5 (P = .008) years. Conclusion Young adults with anterior cruciate ligament injury showed no major difference in frequency of structural tissue damage on MRI scans at 2 and 5 years regardless of treatment. However, the rehabilitation-alone group had less inflammation at 2 and 5 years. © RSNA, 2021 Online supplemental material is available for this article. See also the editorial by Andreisek in this issue.

Patient-Reported Activity Levels Correlate With Early Cartilage Degeneration After Anterior Cruciate Ligament Reconstruction

BACKGROUND

The association between activity level after anterior cruciate ligament (ACL) reconstruction (ACLR) and development of posttraumatic osteoarthritis (PTOA) remains unclear. This study investigated the relationship of patient-reported outcomes and progressive cartilage degenerative changes at 3 years after ACLR.

HYPOTHESIS

Higher activity levels, as measured by Marx scores, are significantly correlated with early cartilage degeneration after ACLR.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

A total of 35 patients (16 women; mean age, 31.0 ± 7.6 years) with isolated ACLR and without pre-existing arthritis were prospectively enrolled. Patients reported Marx activity scores and Knee injury and Osteoarthritis Outcome Score (KOOS) scores and underwent T₁ρ magnetic resonance imaging (MRI) preoperatively, 6 months, 1 year, 2 years, and 3 years after ACLR with soft tissue graft (22 autograft). The change in cartilage relaxation times between preoperative and 3-year imaging was used to identify cartilage degeneration, defined as an increase in T₁ρ values by 14.3%. Correlation between Marx activity levels, KOOS scores, and T₁ρ degeneration was performed with the Spearman rank test. The Fisher exact test was used to test for association between Marx activity score cutoffs and degeneration. The Student t test was used to compare Whole-Organ Magnetic Resonance Imaging Score (WORMS) and T₁ρ relaxation times. Significance was defined as P < .05.

RESULTS

Sixteen patients (45.7%) showed evidence of cartilage degeneration at 3 years, most frequently in the medial compartment (n = 12; 34%). Higher Marx activity scores at 3 years correlated with cartilage degeneration in the medial femur (rho = 0.34; P = .045), and medial tibia (rho = 0.43; P = .01). A Marx score of 11 or greater at 3 years was significantly associated with medial compartment degeneration (P = .03), with a positive predictive value of 52.6%. No Marx score cutoff at years 1 or 2 predicted future cartilage degeneration. The KOOS Quality of Life score was inversely correlated with cartilage degeneration (rho = 0.38; P = .02). WORMS did not correlate with degeneration of the medial compartment.

CONCLUSION

Increased activity at 3 years after ACLR was significantly associated with increased risk of medial compartment PTOA. While further research is needed to fully define these relationships, patients may be counseled that return to Marx activity levels of greater than 11 may be associated with a higher risk of medial compartment cartilage degeneration.

Posttraumatic osteoarthritis: what have we learned to advance osteoarthritis?

PURPOSE OF REVIEW

Current thinking in the study of posttraumatic osteoarthritis (PTOA) is overviewed: the osteoarthritis which follows acute joint injury. The review particularly highlights important publications in the last 18 months, also reflecting on key older literature, in terms of what have we have we learned and have yet to learn from PTOA, which can advance the osteoarthritis field as a whole.

RECENT FINDINGS

PTOA is a mechanically driven disease, giving insight into mechanical drivers for osteoarthritis. A mechanosensitive molecular tissue injury response (which includes activation of pain, degradative and also repair pathways) is triggered by acute joint injury and seen in osteoarthritis. Imaging features of PTOA are highly similar to osteoarthritis, arguing against it being a different phenotype. The inflammatory pathways activated by injury contribute to early joint symptoms. However, later structural changes appear to be dissociated from traditional measures of synovial inflammation.

SUMMARY

PTOA remains an important niche in which to understand processes underlying osteoarthritis and seek interventional targets. Whether PTOA has true molecular or clinical differences to osteoarthritis as a whole remains to be understood. This knowledge is important for a field where animal modelling of the disease relies heavily on the link between injury and osteoarthritis.

Meniscus or Cartilage Injury at the Time of Anterior Cruciate Ligament Tear Is Associated With Worse Prognosis for Patient-Reported Outcome 2 to 10 Years After Anterior Cruciate Ligament Injury: A Systematic Review

OBJECTIVES

(1) To assess prognostic factors for patient-reported outcome measures (PROMs) and physical activity 2 to 10 years after anterior cruciate ligament reconstruction (ACLR) or anterior cruciate ligament (ACL) injury, and (2) to assess differences in prognostic factors between patients treated with ACLR and with rehabilitation alone.

DESIGN

Prognosis systematic review.

LITERATURE SEARCH

Systematic searches were performed in PubMed, Web of Science, and SPORTDiscus.

STUDY SELECTION CRITERIA

We selected prospective cohort studies and randomized clinical trials that included adults or adolescents undergoing either ACLR or rehabilitation alone after ACL rupture. Studies had to assess the statistical association between potential prognostic factors (factors related to patient characteristics, injury, or knee symptoms/function measured at baseline or within 1 year) and outcomes (PROMs and physical activity).

DATA SYNTHESIS

Our search yielded 997 references. Twenty studies met the inclusion criteria. Seven studies with low or moderate risk of bias remained for data synthesis.

RESULTS

Moderate-certainty evidence indicated that concomitant meniscus and cartilage injuries were prognostic factors for worse PROMs 2 to 10 years after ACLR. Very low-certainty evidence suggested that body mass index, smoking, and baseline PROMs were prognostic factors for worse outcome. Very low-certainty evidence suggested that female sex and a worse baseline Marx Activity Rating Scale score were prognostic factors for a worse Marx Activity Rating Scale score 2 to 10 years after ACLR. There was a lack of studies on prognostic factors after rehabilitation alone.

CONCLUSION

Concomitant meniscus and cartilage injuries were prognostic factors for worse long-term PROMs after ACLR. The certainty was very low for other prognostic factors. J Orthop Sports Phys Ther 2020;50(9):490-502. Epub 1 Aug 2020. doi:10.2519/jospt.2020.9451.

Clinical Outcomes After Anterior Cruciate Ligament Injury: Panther Symposium ACL Injury Clinical Outcomes Consensus Group

A stringent outcome assessment is a key aspect of establishing evidence-based clinical guidelines for anterior cruciate ligament (ACL) injury treatment. To establish a standardized assessment of clinical outcome after ACL treatment, a consensus meeting including a multidisciplinary group of ACL experts was held at the ACL Consensus Meeting Panther Symposium, Pittsburgh, Pennsylvania, USA, in June 2019. The aim was to establish a consensus on what data should be reported when conducting an ACL outcome study, what specific outcome measurements should be used, and at what follow-up time those outcomes should be assessed. The group reached consensus on 9 statements by using a modified Delphi method. In general, outcomes after ACL treatment can be divided into 4 robust categories: early adverse events, patient-reported outcomes (PROs), ACL graft failure/recurrent ligament disruption, and clinical measures of knee function and structure. A comprehensive assessment after ACL treatment should aim to provide a complete overview of the treatment result, optimally including the various aspects of outcome categories. For most research questions, a minimum follow-up of 2 years with an optimal follow-up rate of 80% is necessary to achieve a comprehensive assessment. This should include clinical examination, any sustained reinjuries, validated knee-specific PROs, and health-related quality of life questionnaires. In the midterm to long-term follow-up, the presence of osteoarthritis should be evaluated. This consensus paper provides practical guidelines for how the aforementioned entities of outcomes should be reported and suggests the preferred tools for a reliable and valid assessment of outcome after ACL treatment.

Size of Initial Bone Bruise Predicts Future Lateral Chondral Degeneration in ACL Injuries: A Radiographic Analysis

Background:

Bone marrow contusions are common after an acute anterior cruciate ligament (ACL) injury. It is unknown whether the severity of this initial bruise can predict the potential of developing chondral changes even after ACL reconstructive surgery (ACLR).

Purpose:

To investigate whether the initial bone bruise area could be predictive of progressive chondral defects.

Study Design:

Cohort study; Level of evidence, 3.

Methods:

A retrospective chart review was performed to capture patients with an acute ACL injury with pre- and post-ACLR magnetic resonance imaging (MRI) between January 2000 and December 2017. Lesion areas were measured on initial MRI, and chondral wear was graded on final imaging by use of the modified Outerbridge classification. An ordinal model was created to determine whether the initial area was a significant predictor for future chondral degeneration.

Results:

A total of 40 patients with a mean age of 34.5 ± 12.6 years were included for analysis. All patients underwent ACLR at a mean 139 ± 64 days from initial injury. A lateral tibial and femoral bone bruise was most commonly present in patients (77.5% and 62.5%, respectively). A medial femoral bone bruise was found in only 12.5% (5/40) of patients. The initial contusion area significantly correlated with increasing chondral wear over time in the tibia and lateral femoral condyle (P < .001). Patients with a bone bruise encompassing 100% of the lateral femoral compartment on MRI had a 74% chance of having grade 3 or 4 chondral changes at 5 years (P = .001). Absence of a bone bruise on initial MRI was the greatest predictor of no cartilage wear at 5 years in all compartments (P < .001). The presence of a concomitant lateral meniscal injury increased the risk of developing type 3 or 4 chondral wear in the lateral tibial plateau (P = .012) but did not pose increased risk of femoral wear (P = .23).

Conclusion:

A significant relationship between area of initial bone bruise at the time of injury and progressive posttraumatic chondral disease was found in the tibial and lateral femoral compartments.

Clinical outcomes after anterior cruciate ligament injury: panther symposium ACL injury clinical outcomes consensus group

PURPOSE

A stringent outcome assessment is a key aspect for establishing evidence-based clinical guidelines for anterior cruciate ligament (ACL) injury treatment. The aim of this consensus statement was to establish what data should be reported when conducting an ACL outcome study, what specific outcome measurements should be used and at what follow-up time those outcomes should be assessed.

METHODS

To establish a standardized approach to assessment of clinical outcome after ACL treatment, a consensus meeting including a multidisciplinary group of ACL experts was held at the ACL Consensus Meeting Panther Symposium, Pittsburgh, PA; USA, in June 2019. The group reached consensus on nine statements by using a modified Delphi method.

RESULTS

In general, outcomes after ACL treatment can be divided into four robust categories-early adverse events, patient-reported outcomes, ACL graft failure/recurrent ligament disruption and clinical measures of knee function and structure. A comprehensive assessment following ACL treatment should aim to provide a complete overview of the treatment result, optimally including the various aspects of outcome categories. For most research questions, a minimum follow-up of 2 years with an optimal follow-up rate of 80% is necessary to achieve a comprehensive assessment. This should include clinical examination, any sustained re-injuries, validated knee-specific PROs and Health-Related Quality of Life questionnaires. In the mid- to long-term follow-up, the presence of osteoarthritis should be evaluated.

CONCLUSION

This consensus paper provides practical guidelines for how the aforementioned entities of outcomes should be reported and suggests the preferred tools for a reliable and valid assessment of outcome after ACL treatment.

LEVEL OF EVIDENCE

V.

Establishing outcome measures in early knee osteoarthritis

The classification and monitoring of individuals with early knee osteoarthritis (OA) are important considerations for the design and evaluation of therapeutic interventions and require the identification of appropriate outcome measures. Potential outcome domains to assess for early OA include patient-reported outcomes (such as pain, function and quality of life), features of clinical examination (such as joint line tenderness and crepitus), objective measures of physical function, levels of physical activity, features of imaging modalities (such as of magnetic resonance imaging) and biochemical markers in body fluid. Patient characteristics such as adiposity and biomechanics of the knee could also have relevance to the assessment of early OA. Importantly, research is needed to enable the selection of outcome measures that are feasible, reliable and validated in individuals at risk of knee OA or with early knee OA. In this Perspectives article, potential outcome measures for early symptomatic knee OA are discussed, including those measures that could be of use in clinical practice and/or the research setting.

Patterns of cartilage degeneration in knees with medial tibiofemoral offset

OBJECTIVE

To determine if radiographic medial tibiofemoral offset (MTFO) is associated with: (1) magnetic resonance imaging (MRI) pathology of cartilage, meniscus, and ligament; and (2) a distinct pattern of lateral cartilage degeneration on MRI.

MATERIALS AND METHODS

Three hundred consecutive adult knee MRIs with anteroposterior (AP) radiographs were retrospectively reviewed, and 145 studies were included. MTFO was defined as a medial extension of the medial femoral condyle beyond the articular surface of the medial tibial plateau on weight-bearing AP radiographs. The patients were then divided into the MTFO (n = 61) or no-offset (n = 84) groups. On MRI data obtained on a 1.5-Tesla system, articular cartilage of the femoral condyle and tibial plateau were graded using a modified Outerbridge classification (36 sub-regions similar to whole-organ MRI Score (WORMS) system). In addition, MR pathology of the ACL, MCL, LCL, medial and lateral menisci, were determined.

RESULTS

Significantly increased (ANOVA p < 0.007) MR grade of the ligaments, menisci, and cartilage in the MTFO group (ranging from 0.3 to 2.5) compared to the control group (0.2 to 1.1). Color maps of the cartilage grades suggested a marked difference in both severity of degeneration and regional variations between the groups. MTFO group exhibited focally increased cartilage grades in the central, non-weight regions of lateral compartment (region p = 0.07 to 0.12, interaction p = 0.05 to 0.1).

CONCLUSIONS

MTFO is associated with overall degeneration of the knee and features a distinct lateral cartilage degeneration pattern, which may reflect non-physiologic contact of the cartilage between the lateral tibial eminence and lateral central femoral condyle.

Spatial distribution and temporal progression of T2 relaxation time values in knee cartilage prior to the onset of cartilage lesions - data from the Osteoarthritis Initiative (OAI)

PURPOSE

To investigate compositional changes of knee cartilage at the site of newly appearing cartilage lesions and the surrounding cartilage 1-4 years prior to lesion onset using quantitative T2-measurements.

METHODS

Fifty-seven cartilage plates with newly appearing cartilage lesions from 45 knees (cases) and 52 plates from 26 control knees from the Osteoarthritis Initiative (OAI) cohort (controls) were evaluated. Using MRI T2-mapping, composition of local (the site of future lesions) and surrounding cartilage (remainder of the cartilage plate) was assessed 1-4 years prior to lesion onset. Analogous cartilage ROIs in control plates without cartilage lesions were assessed over 1-4 years. Mixed models were used to compare T2-means and change rates between local and surrounding cartilage within cases and controls, and to compare change rates in local and surrounding cartilage between cases and controls, adjusting for covariates.

RESULTS

Four years prior to lesion onset, we found that local cartilage ROIs had higher T2-values compared to the surrounding cartilage. No such differences were found in control plates. In cases mean local T2-values were persistantly elevated compared to the surrounding cartilage prior to lesion onset reaching significance 1 year prior (+2.94 ms, p = 0.012). T2-values of the surrounding cartilage were also persistantly higher in cases compared to controls, reaching significance 2 years prior to lesion onset (+3.61 ms, p = 0.003).

CONCLUSION

The findings of our study support the concept of compositional cartilage changes as a mechanism for cartilage degradation and that both diffuse and focal changes of cartilage composition within a cartilage plate precede the development of cartilage lesions.

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.

Longitudinal analysis of tibiofemoral cartilage contact area and position in ACL reconstructed patients

Patients who have suffered ACL injury are more likely to develop early onset post-traumatic osteoarthritis despite reconstruction. The purpose of our study was to evaluate the longitudinal changes in the tibiofemoral cartilage contact area size and location after ACL injury and reconstruction. Thirty-one patients with isolated unilateral ACL injury were followed with T₂ weighted Fast Spin Echo, T_1ρ and T₂ MRI at baseline prior to reconstruction, and 6 months, 1 year, and 2 years after surgery. Areas were delineated in FSE images with an in-house Matlab program using a spline-based semi-automated segmentation algorithm. Tibiofemoral contact area and centroid position along the anterior-posterior axis were calculated along with T_1ρ and T₂ relaxation times on both the injured and non-injured knees. At baseline, the injured knees had significantly smaller and more posteriorly positioned contact areas on the medial tibial surface compared to corresponding healthy knees. These differences persisted 6 months after reconstruction. Moreover, subjects with more anterior medial centroid positions at 6 months had elevated T_1ρ and T₂ measures in the posterior medial tibial plateau at 1 year. Changes in contact area and centroid position after ACL injury and reconstruction may characterize some of the mechanical factors contributing to post-traumatic osteoarthritis. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:2718-2727, 2018.

Worsening Knee Osteoarthritis Features on Magnetic Resonance Imaging 1 to 5 Years After Anterior Cruciate Ligament Reconstruction

BACKGROUND

An anterior cruciate ligament (ACL) injury is a well-established risk factor for the long-term development of radiographic osteoarthritis (OA). However, little is known about the early degenerative changes (ie, <5 years after injury) of individual joint features (ie, cartilage, bone marrow), which may be reversible and responsive to interventions.

PURPOSE

To describe early degenerative changes between 1 and 5 years after ACL reconstruction (ACLR) on magnetic resonance imaging (MRI) and explore participant characteristics associated with these changes.

STUDY DESIGN

Case-control study; Level of evidence, 3.

METHODS

Seventy-eight participants (48 men; median age, 32 years; median body mass index [BMI], 26 kg/m²) underwent 3.0-T MRI at 1 and 5 years after primary hamstring autograft ACLR. Early tibiofemoral and patellofemoral OA features were assessed with the MRI Osteoarthritis Knee Score. The primary outcome was worsening (ie, incident or progressive) cartilage defects, bone marrow lesions (BMLs), osteophytes, and meniscal lesions. Logistic regression with generalized estimating equations evaluated participant characteristics associated with worsening features.

RESULTS

Worsening of cartilage defects in any compartment occurred in 40 (51%) participants. Specifically, worsening in the patellofemoral and medial and lateral tibiofemoral compartments was present in 34 (44%), 8 (10%), and 10 (13%) participants, respectively. Worsening patellofemoral and medial and lateral tibiofemoral BMLs (14 [18%], 5 [6%], and 10 [13%], respectively) and osteophytes (7 [9%], 8 [10%], and 6 [8%], respectively) were less prevalent, while 17 (22%) displayed deteriorating meniscal lesions. Worsening of at least 1 MRI-detected OA feature, in either the patellofemoral or tibiofemoral compartment, occurred in 53 (68%) participants. Radiographic OA in any compartment was evident in 5 (6%) and 16 (21%) participants at 1 and 5 years, respectively. A high BMI (>25 kg/m²) was consistently associated with elevated odds (between 2- and 5-fold) of worsening patellofemoral and tibiofemoral OA features.

CONCLUSION

High rates of degenerative changes occur in the first 5 years after ACLR, particularly the development and progression of patellofemoral cartilage defects. Older patients with a higher BMI may be at particular risk and should be educated about this risk.

Frontal Plane Knee Mechanics and Early Cartilage Degeneration in People With Anterior Cruciate Ligament Reconstruction: A Longitudinal Study

BACKGROUND

Abnormal frontal plane gait mechanics are known risk factors for knee osteoarthritis, but their role in early cartilage degeneration after anterior cruciate ligament reconstruction (ACLR) is not well understood. Hypothesis/Purpose: The objective was to evaluate the association of frontal plane gait mechanics with medial knee cartilage magnetic resonance (MR) relaxation times over 1 year in patients with ACLR and controls. It was hypothesized that (1) there will be an increase in frontal plane medial knee loading and medial knee MR relaxation times over time in the patients with ACLR, and (2) increases in frontal plane medial knee loading will be associated with an increase in medial knee MR relaxation times.

STUDY DESIGN

Case-control study; Level of evidence, 3.

METHODS

Patients with ACLR (n = 37) underwent walking gait analyses and bilateral quantitative MR imaging (MRI) before surgery and at 6 and 12 months after ACLR. Healthy control participants (n = 13) were evaluated at baseline and 12 months. Gait variables included peak knee adduction moment (KAM), KAM impulse, and peak knee adduction angle. MRI variables included medial femur and medial tibia whole compartment and subregional T_1ρ and T₂ relaxation times. Statistical analyses included a comparison of changes over time for gait and MRI variables, correlations between changes in gait and MRI variables over time, and differences in change in MRI variables in patients who showed an increase versus decrease in KAM impulse.

RESULTS

There were significant increases in medial T_1ρ (Δ 4%-11%) and T₂ (Δ 2%-10%) relaxation times from baseline to 6 months for both knees in the ACLR group and in KAM (Δ 13%) for the injured knee. From baseline to 6 months, patients who had an increase in KAM impulse in the injured knee had a greater increase in medial T_1ρ and T₂ relaxation times as compared with those who did not have an increase in KAM impulse. Longitudinal changes for the control group were not significant.

CONCLUSION

There is an increase in medial knee relaxation times over the first 6 months after ACLR. People with an increase in medial knee loading show an increase in medial knee relaxation times when compared with those who do not have an increase in medial knee loading over the first 6 months.

A comparison of patellofemoral cartilage morphology and deformation in anterior cruciate ligament deficient versus uninjured knees

Anterior cruciate ligament (ACL) deficient patients have an increased rate of patellofemoral joint (PFJ) osteoarthritis (OA) as compared to the general population. Although the cause of post-injury OA is multi-factorial, alterations in joint biomechanics may predispose patients to cartilage degeneration. This study aimed to compare in vivo PFJ morphology and mechanics between ACL deficient and intact knees in subjects with unilateral ACL ruptures. Eight male subjects underwent baseline MRI scans of both knees. They then performed a series of 60 single-legged hops, followed by a post-exercise MRI scan. This process was repeated for the contralateral knee. The MR images were converted into three-dimensional surface models of cartilage and bone in order to assess cartilage thickness distributions and strain following exercise. Prior to exercise, patellar cartilage was significantly thicker in intact knees as compared to ACL deficient knees by 1.8%. In response to exercise, we observed average patellar cartilage strains of 5.4 ± 1.1% and 2.5 ± 1.4% in the ACL deficient and intact knees, respectively. Importantly, the magnitude of patellar cartilage strain in the ACL deficient knees was significantly higher than in the intact knees. However, while trochlear cartilage experienced a mean strain of 2.4 ± 1.6%, there was no difference in trochlear cartilage strain between the ACL deficient and uninjured knees. In summary, we found that ACL deficiency was associated with decreased patellar cartilage thickness and increased exercise-induced patellar cartilage strain when compared to the uninjured contralateral knees.

MRI observations of patellar tendon length change after ACL reconstruction with hamstring autografts

The post-operative patellar tendon length was studied to evaluate the possible tendon length change after anterior cruciate ligament (ACL) reconstruction with hamstring autografts. The Insall-Salvati index, modified Insall-Salvati index, curved modified Insall-Salvati index and Caton-Deschamps index were observed by MRI during a follow-up period of 12 weeks on 20 ACL reconstructed knees. The results showed no patellar baja or alta pre-existed on those ACL injured patients. After a follow-up period of 12 weeks, no patellar tendon length change was observed. It is suggested that the change of patella was not the primary reason that may contribute to the premature patellofemoral joint osteoarthritis after ACL reconstruction.

Patient Knowledge and Beliefs About Knee Osteoarthritis After Anterior Cruciate Ligament Injury and Reconstruction

OBJECTIVE

To explore patients' knowledge and beliefs about osteoarthritis (OA) and OA risk following anterior cruciate ligament (ACL) injury, to explore the extent to which information about these risks is provided by health professionals, and to examine associations among participant characteristics, knowledge, and risk beliefs and health professional advice.

METHODS

A custom-designed survey was conducted in Australian and American adults who sustained an ACL injury, with or without reconstruction, 1-5 years prior. The survey comprised 3 sections: participant characteristics, knowledge about OA and OA risk, and health professional advice.

RESULTS

Complete data sets from 233 eligible respondents were analyzed. Most (70%, n = 164) rated themselves as being at greater risk of OA than their healthy peers, although only 56% (n = 130) were able to identify the correct OA definition. While most agreed that ACL (73%, n = 168) and/or meniscal injuries (n = 181, 78%) increase the risk of OA, 65% (n = 152) believed that ACL reconstruction reduced the risk of OA, or they did not know. A total of 27% (n = 62) recalled discussing their OA risk with a health professional. Participants who were female, younger, or had a lower body mass index or higher physical activity level were more likely to recognize meniscal tears and meniscectomy as risk factors of OA. A history of professional advice was associated with beliefs about increased OA risks.

CONCLUSION

Patients sustaining an ACL injury require better education from health professionals about OA as a disease entity and their elevated risk of OA, irrespective of whether or not they undergo surgical reconstruction.

Gait mechanics in those with/without medial compartment knee osteoarthritis 5 years after anterior cruciate ligament reconstruction

The objective of the study was to evaluate differences in gait mechanics 5 years after unilateral anterior cruciate ligament reconstruction surgery, for non-osteoarthritic (n = 24) versus osteoarthritic (n = 9) subjects. For the involved knee, the osteoarthritic group demonstrated significantly lower peak knee flexion angles (non-osteoarthritic = 24.3 ± 4.6°, osteoarthritic = 19.1 ± 2.9°, p = 0.01) and peak knee flexion moments (non-osteoarthritic = 5.3 ± 1.2% Body Weight × Height, osteoarthritic = 4.4 ± 1.2% Body Weight × Height, p = 0.05). Differences in peak knee adduction moment approached significance, with a higher magnitude for the osteoarthritic group (non-osteoarthritic = 2.4 ± 0.8% Body Weight × Height, osteoarthritic = 2.9 ± 0.5% Body Weight × Height, p = 0.09). Peak medial compartment joint load was evaluated using electromyography-informed neuromusculoskeletal modeling. Peak medial compartment joint load in the involved knee for the two groups was not different (non-osteoarthritic = 2.4 ± 0.4 Body Weight, osteoarthritic = 2.3 ± 0.6 Body Weight). The results suggest that subjects with dissimilar peak knee moments can have similar peak medial compartment joint load magnitudes. There was no evidence of inter-limb asymmetry for either group. Given the presence of inter-group differences (non-osteoarthritic vs. osteoarthritic) for the involved knee, but an absence of inter-limb asymmetry in either group, it may be necessary to evaluate how symmetry is achieved, over time, and to differentiate between good versus bad inter-limb symmetry, when evaluating knee gait parameters. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:625-633, 2017.

Cartilage morphology at 2-3 years following anterior cruciate ligament reconstruction with or without concomitant meniscal pathology

PURPOSE

To examine differences in cartilage morphology between young adults 2-3 years post-anterior cruciate ligament reconstruction (ACLR), with or without meniscal pathology, and control participants.

METHODS

Knee MRI was performed on 130 participants aged 18-40 years (62 with isolated ACLR, 38 with combined ACLR and meniscal pathology, and 30 healthy controls). Cartilage defects, cartilage volume and bone marrow lesions (BMLs) were assessed from MRI using validated methods.

RESULTS

Cartilage defects were more prevalent in the isolated ACLR (69 %) and combined group (84 %) than in controls (10 %, P < 0.001). Furthermore, the combined group showed higher prevalence of cartilage defects on medial femoral condyle (OR 4.7, 95 % CI 1.3-16.6) and patella (OR 7.8, 95 % CI 1.5-40.7) than the isolated ACLR group. Cartilage volume was lower in both ACLR groups compared with controls (medial tibia, lateral tibia and patella, P < 0.05), whilst prevalence of BMLs was higher on lateral tibia (P < 0.001), with no significant differences between the two ACLR groups for either measure.

CONCLUSIONS

Cartilage morphology was worse in ACLR patients compared with healthy controls. ACLR patients with associated meniscal pathology have a higher prevalence of cartilage defects than ACLR patients without meniscal pathology. The findings suggest that concomitant meniscal pathology may lead to a greater risk of future OA than isolated ACLR.

LEVEL OF EVIDENCE

III.

Hip and Knee Osteoarthritis Affects Younger People, Too

Synopsis Although osteoarthritis (OA) has traditionally been considered a disease of older age, hip and knee OA can and does affect younger adults, with a profound impact on psychosocial well-being and work capacity. Obesity and a history of traumatic knee injury (eg, anterior cruciate ligament rupture and/or meniscal tear) are key risk factors for the accelerated development of knee OA, while structural hip deformities (including those contributing to femoroacetabular impingement syndrome) are strong predictors of early-onset hip OA. In view of these associations, rising rates of obesity and sports injuries are concerning, and may signal a future surge in OA incidence among younger people. Assessment of hip and knee OA in younger people should focus on a patient-centered history, comprehensive physical examination, performance-based measures, and patient-reported outcome measures to enable monitoring of symptoms and function over time. Referral for imaging should be reserved for people presenting with atypical signs or symptoms that may indicate diagnoses other than OA. Nonpharmacological approaches are core strategies for the management of hip and knee OA in younger people, and these include appropriate disease-related education, activity modification (including for work-related tasks), physical therapist- prescribed exercise programs to address identified physical impairments, and weight control or weight loss. High-quality evidence has shown no benefit of arthroscopy for knee OA, and there are no published clinical trials to support the use of hip arthroscopy for OA. Referral for joint-conserving or joint replacement surgery should be considered when nonpharmacological and pharmacological management strategies are no longer effective. J Orthop Sports Phys Ther 2017;47(2):67-79. doi:10.2519/jospt.2017.7286.

Degenerative Changes in the Knee 2 Years After Anterior Cruciate Ligament Rupture and Related Risk Factors: A Prospective Observational Follow-up Study

BACKGROUND

Anterior cruciate ligament (ACL) rupture is a well-known risk factor for development of knee osteoarthritis. Early identification of those patients at risk and early identification of the process of ACL rupture leading to osteoarthritis may aid in preventing the onset or progression of osteoarthritis.

PURPOSE

To identify early degenerative changes as assessed on magnetic resonance imaging (MRI) after 2-year follow-up in patients with a recent ACL rupture and to evaluate which determinants are related to these changes.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

Included in this study were 154 adults aged between 18 and 45 years with acute ACL rupture diagnosed by physical examination and MRI, without previous knee trauma or surgery, and without osteoarthritic changes on radiographs. A total of 143 patients completed the 2-year follow-up, and the results in this study apply to these 143 patients. All patients were treated according to the Dutch guideline on ACL injury. Of the 143 patients, 50 patients were treated nonoperatively during the 2-year follow-up period. Main outcome was early degenerative changes assessed on MRI defined as progression of cartilage defects and osteophytes in tibiofemoral and patellofemoral compartments. Patient characteristics, activity level, functional instability, treatment type, and trauma-related variables were evaluated as determinants.

RESULTS

The median time between MRI at baseline and MRI at 2-year follow-up was 25.9 months (interquartile range, 24.7-26.9 months). Progression of cartilage defects in the medial and lateral tibiofemoral compartments was present in 12% and 27% of patients, and progression of osteophytes in tibiofemoral and patellofemoral compartments was present in 10% and 8% of patients, respectively. The following determinants were positively significantly associated with early degenerative changes: male sex (odds ratio [OR], 4.43; 95% CI, 1.43-13.66; P = .010), cartilage defect in the medial tibiofemoral compartment at baseline (OR, 3.66; 95% CI, 1.04-12.95; P = .044), presence of bone marrow lesions in the medial tibiofemoral compartment 1 year after trauma (OR, 5.19; 95% CI, 1.56-17.25; P = .007), joint effusion 1 year after trauma (OR, 4.19; 95% CI, 1.05-16.72; P = .042), and presence of meniscal tears (OR, 6.37; 95% CI, 1.94-20.88; P = .002). When the patients were categorized into 3 treatment groups (nonoperative, reconstruction <6 months after ACL rupture, and reconstruction ≥6 months after ACL rupture), there was no significant relationship between the treatment options and the development of early degenerative changes.

CONCLUSION

Two years after ACL rupture, early degenerative changes were assessed on MRI. Concomitant medial cartilage defect and meniscal injury, male sex, persistent bone marrow lesions in the medial tibiofemoral compartment, and joint effusion are risk factors for degenerative changes.

A Systematic Summary of Systematic Reviews on the Topic of the Anterior Cruciate Ligament

BACKGROUND

There has been a substantial increase in the amount of systematic reviews and meta-analyses published on the anterior cruciate ligament (ACL).

PURPOSE

To quantify the number of systematic reviews and meta-analyses published on the ACL in the past decade and to provide an overall summary of this literature.

STUDY DESIGN

Systematic review; Level of evidence, 4.

METHODS

A systematic review of all ACL-related systematic reviews and meta-analyses published between January 2004 and September 2014 was performed using PubMed, MEDLINE, and the Cochrane Database. Narrative reviews and non-English articles were excluded.

RESULTS

A total of 1031 articles were found, of which 240 met the inclusion criteria. Included articles were summarized and divided into 17 topics: anatomy, epidemiology, prevention, associated injuries, diagnosis, operative versus nonoperative management, graft choice, surgical technique, fixation methods, computer-assisted surgery, platelet-rich plasma, rehabilitation, return to play, outcomes assessment, arthritis, complications, and miscellaneous.

CONCLUSION

A summary of systematic reviews on the ACL can supply the surgeon with a single source for the most up-to-date synthesis of the literature.

Changes in the T2 relaxation value of the tibiofemoral articular cartilage about 6 months after anterior cruciate ligament reconstruction using the double-bundle technique

OBJECTIVE

To evaluate T2 relaxation values (T2RVs) of knee joint cartilage after double-bundle anterior cruciate ligament reconstruction (DB-ACLR) in a 6-month follow-up and to correlate changes between T2RVs with meniscal status and clinical findings.

METHODS

27 patients who underwent DB-ACLR and MRI before and 6 months after surgery, and 27 control subjects were enrolled. We compared T2RVs of the control vs pre-operative MR and pre-operative vs post-operative MR using 28 subcompartments, including superficial and deep layers. Correlations between T2RV changes with meniscal status and clinical data were examined.

RESULTS

The pre-operative T2RV was significantly higher than that of the control group in the medial tibia (posterior-superficial), posterior medial femur (superficial) and posterior lateral femur (superficial and deep). The post-operative T2RV was significantly higher than that of pre-operative T2RV in the posterior medial femur (superficial), medial tibia (anterior-deep and central-deep), lateral femur (anterior-deep, anterior-superficial and central-superficial) and posterior medial femur (deep). Moderate positive correlations between pre-operative and post-operative T2RV changes were found at the posterior medial femur (interval between injury and MR examination, and instability) and posterior lateral femur (Lysholm score).

CONCLUSION

Patients with anterior cruciate ligament injury followed by DB-ACLR presented short-term subcompartment T2RV changes at the medial femur, lateral femur and medial tibia. Meniscal status did not affect T2RV; however, clinical findings influenced T2RV at the posterior grooves of the medial and lateral femoral condyles.

ADVANCES IN KNOWLEDGE

Patients submitted to DB-ACLR presented T2RV changes in both femoral and medial tibial condyles 6 months after the surgery, affecting not just the weight-bearing areas, but also the less-weight-bearing areas.

Decreased Knee Joint Loading Associated With Early Knee Osteoarthritis After Anterior Cruciate Ligament Injury

BACKGROUND

Anterior cruciate ligament (ACL) injury predisposes individuals to early-onset knee joint osteoarthritis (OA). Abnormal joint loading is apparent after ACL injury and reconstruction. The relationship between altered joint biomechanics and the development of knee OA is unknown.

HYPOTHESIS

Altered knee joint kinetics and medial compartment contact forces initially after injury and reconstruction are associated with radiographic knee OA 5 years after reconstruction.

STUDY DESIGN

Case-control study; Level of evidence, 3.

METHODS

Individuals with acute, unilateral ACL injury completed gait analysis before (baseline) and after (posttraining) preoperative rehabilitation and at 6 months, 1 year, and 2 years after reconstruction. Surface electromyographic and knee biomechanical data served as inputs to an electromyographically driven musculoskeletal model to estimate knee joint contact forces. Patients completed radiographic testing 5 years after reconstruction. Differences in knee joint kinetics and contact forces were compared between patients with and those without radiographic knee OA.

RESULTS

Patients with OA walked with greater frontal plane interlimb differences than those without OA (nonOA) at baseline (peak knee adduction moment difference: 0.00 ± 0.08 N·m/kg·m [nonOA] vs -0.15 ± 0.09 N·m/kg·m [OA], P = .014; peak knee adduction moment impulse difference: -0.001 ± 0.032 N·m·s/kg·m [nonOA] vs -0.048 ± 0.031 N·m·s/kg·m [OA], P = .042). The involved limb knee adduction moment impulse of the group with osteoarthritis was also lower than that of the group without osteoarthritis at baseline (0.087 ± 0.023 N·m·s/kg·m [nonOA] vs 0.049 ± 0.018 N·m·s/kg·m [OA], P = .023). Significant group differences were absent at posttraining but reemerged 6 months after reconstruction (peak knee adduction moment difference: 0.02 ± 0.04 N·m/kg·m [nonOA] vs -0.06 ± 0.11 N·m/kg·m [OA], P = .043). In addition, the OA group walked with lower peak medial compartment contact forces of the involved limb than did the group without OA at 6 months (2.89 ± 0.52 body weight [nonOA] vs 2.10 ± 0.69 body weight [OA], P = .036).

CONCLUSION

Patients who had radiographic knee OA 5 years after ACL reconstruction walked with lower knee adduction moments and medial compartment joint contact forces than did those patients without OA early after injury and reconstruction.

Changes to the articular cartilage thickness profile of the tibia following anterior cruciate ligament injury

OBJECTIVES

We sought to determine if anterior cruciate ligament (ACL)-injured subjects demonstrated side-to-side differences in tibial cartilage thickness soon after injury, and if uninjured-control subjects displayed side-to-side symmetry in cartilage thickness. Second, we aimed to investigate associations between body mass index (BMI), cross-sectional area (CSA) of the proximal tibia, and articular cartilage thickness differences.

METHODS

Bilateral Magnetic Resonance Images (MRIs) were obtained on 88 ACL-injured subjects (27 male; 61 female) a mean 27 days post-injury, and 88 matched uninjured control subjects. Within ACL-injured and uninjured control subjects, side-to-side differences in medial and lateral tibial articular cartilage thickness were analyzed with adjustment for tibial position relative to the femur during MRI acquisition. Associations between tibial CSA and cartilage thickness differences were tested within high and low BMI groups.

RESULTS

Within the medial tibial compartment, ACL-injured females displayed significant increases: mean (confidence interval (CI)) = +0.18 mm (0.17, 0.19) and decreases: mean (CI) = -0.14 mm (-0.13, -0.15) in tibial cartilage thickness within the central and posterior cartilage regions respectively. Adjustment for tibial position revealed a decreased area of significant cartilage thickness differences, though 46% of points maintained significance. In the lateral compartment anterior region, there was a significantly different relationship between cartilage thickness differences and CSA, within high and low BMI groups (BMI group*CSA interaction, P = 0.007). Within the low BMI group, a significant negative correlation between cartilage thickness and CSA was identified (P = 0.03).

CONCLUSIONS

ACL-injured females displayed cartilage thickness differences in the central, and posterior medial tibial cartilage regions. Tibial position effected thickness differences, but did not account for all significant differences.

The role of imaging in osteoarthritis

Osteoarthritis (OA) is the most prevalent joint disorder with no approved disease-modifying treatment available. The importance of imaging in assessing all joint structures involved in the disease process, including articular cartilage, meniscus, subarticular bone marrow, and synovium for diagnosis, prognostication, and follow-up, has been well recognized. In daily clinical practice, conventional radiography is still the most commonly used imaging technique for the evaluation of a patient with known or suspected OA and radiographic outcome measures are still the only approved end point by regulatory authorities in clinical trials. The ability of magnetic resonance imaging (MRI) to visualize all joint structures in three-dimensional fashion including tissue ultrastructure has markedly deepened our understanding of the natural history of the disease. This article describes the roles and limitations of different imaging modalities for clinical practice and research in OA, with a focus on radiography and MRI and an emphasis on the knee joint.

Anterior Cruciate Ligament OsteoArthritis Score (ACLOAS): Longitudinal MRI-based whole joint assessment of anterior cruciate ligament injury

OBJECTIVE

To develop a whole joint scoring system, the Anterior Cruciate Ligament OsteoArthritis Score (ACLOAS), for magnetic resonance imaging (MRI)-based assessment of acute anterior cruciate ligament (ACL) injury and follow-up of structural sequelae, and to assess its reliability.

DESIGN

Baseline and follow-up 1.5 T MRI examinations from 20 patients of the KANON study, a randomized controlled study comparing a surgical and non-surgical treatment strategy, were assessed for up to six longitudinal visits using a novel MRI scoring system incorporating acute structural tissue damage and longitudinal changes including osteoarthritis (OA) features. Joint features assessed were acute osteochondral injury, traumatic and degenerative bone marrow lesions (BMLs), meniscus morphology and extrusion, osteophytes, collateral and cruciate ligaments including ACL graft, Hoffa-synovitis and effusion-synovitis. Cross-sectional (baseline) and longitudinal (all time points and change) intra- and inter-observer reliability was calculated using weighted (w) kappa statistics and overall percent agreement on a compartmental basis (medial tibio-femoral, lateral tibio-femoral, patello-femoral).

RESULTS

Altogether 87 time points were evaluated. Intra-observer reliability ranged between 0.52 (baseline, Hoffa-synovitis) and 1.00 (several features), percent agreement between 52% (all time points, Hoffa-synovitis) and 100% (several features). Inter-observer reliability ranged between 0.00 and 1.00, which is explained by low frequency of some of the features. Altogether, 73% of all assessed 142 parameters showed w-kappa values between 0.80 and 1.00 and 92% showed agreement above 80%.

CONCLUSIONS

ACLOAS allows reliable scoring of acute ACL injury and longitudinal changes. This novel scoring system incorporates features that may be relevant for structural outcome not covered by established OA scoring instruments.