Quantitative magnetic resonance imaging (MRI) morphological analysis of knee cartilage in healthy and anterior cruciate ligament-injured knees

Effects of sex differences on osteoarthritic changes after anterior cruciate ligament reconstruction in rats

The prevalence of primary osteoarthritis is higher in females than males. However, it remains unclear if there are sex differences in the incidence of post-traumatic osteoarthritis after anterior cruciate ligament (ACL) reconstruction. In this study, we aimed to investigate the effects of sex on osteoarthritic changes after ACL reconstruction using an animal model. Rats were divided into the following four groups: male control, male ACL reconstruction, female control, and female ACL reconstruction. ACL reconstruction surgery was performed on the right knees of rats in the ACL reconstruction groups, while rats in the control groups did not undergo knee surgery. At 1, 4, and 12 weeks after surgery, cartilage degeneration in the medial tibial plateau and osteophyte formation in the proximal tibia were histologically assessed. After ACL reconstruction, an increase in the Mankin score, cartilage fissures, and osteophyte formation were detected within 12 weeks in both male and female rats, with similar degrees of these changes between males and females. However, changes in cartilage thickness and chondrocyte density after ACL reconstruction differed between males and females. Cartilage thickening was observed in male rats but not in female rats. The increase in chondrocyte density in the anterior region was detected in both males and females but was more pronounced in female rats. In conclusion, osteoarthritic changes were observed after ACL reconstruction in both male and female rats, but differences in changes in cartilage thickness and chondrocyte density were observed between males and females.

Imageless robotic total knee arthroplasty determines similar coronal plane alignment of the knee (CPAK) parameters to long leg radiographs

BACKGROUND

The coronal plane alignment of the knee (CPAK) classification was first developed using long leg radiographs (LLR) and has since been reported using image-based and imageless robotic total knee arthroplasty (TKA) systems. However, the correspondence between imageless robotics and LLR-derived CPAK parameters has yet to be investigated. This study therefore examined the differences in CPAK parameters determined with LLR and imageless robotic navigation using either generic or optimized cartilage wear assumptions.

METHODS

Medial proximal tibial angle (MPTA) and lateral distal femoral angle (LDFA) were determined from the intraoperative registration data of 61 imageless robotic TKAs using either a generic 2 mm literature-based wear assumption (Navlit) or an optimized wear assumption (Navopt) found using an error minimization algorithm. MPTA and LDFA were also measured from preoperative LLR by two observers and intraclass correlation coefficients (ICCs) were calculated. MPTA, LDFA, joint line obliquity (JLO), and arithmetic hip-knee-ankle angle (aHKA) were compared between the robotic and the average LLR measurements over the two observers.

RESULTS

ICCs between observers for LLR were over 0.95 for MPTA, LDFA, JLO, and aHKA, indicating excellent agreement. Mean CPAK differences were not significant between LLR and Navlit (all differences within 0.6°, P > 0.1) or Navopt (all within 0.1°, P > 0.83). Mean absolute errors (MAE) between LLR and Navlit were: LDFA = 1.4°, MPTA = 2.0°, JLO = 2.1°, and aHKA = 2.7°. Compared to LLR, the generic wear classified 88% and the optimized wear classified 94% of knees within one CPAK group. Bland-Altman comparisons reported good agreement for LLR vs. Navlit and Navopt, with > 95% and > 91.8% of measurements within the limits of agreement across all CPAK parameters, respectively.

CONCLUSIONS

Imageless robotic navigation data can be used to calculate CPAK parameters for arthritic knees undergoing TKA with good agreement to LLR. Generic wear assumptions determined MPTA and LDFA with MAE within 2° and optimizing wear assumptions showed negligible improvement.

Ultrasonographic Assessment of Femoral Cartilage in Individuals With Anterior Cruciate Ligament Reconstruction: A Case-Control Study

CONTEXT

Developing osteoarthritis is common after anterior cruciate ligament reconstruction (ACLR). Monitoring changes in femoral cartilage size after ACLR may be a way to detect the earliest structural alterations before the radiographic onset of osteoarthritis. Diagnostic ultrasonography (US) offers a clinically accessible and valid method for evaluating anterior femoral cartilage size.

OBJECTIVE

To compare the US measurements of anterior femoral cross-sectional area and cartilage thickness between limbs in individuals with a unilateral ACLR and between the ACLR limbs of these individuals and the limbs of uninjured control participants.

DESIGN

Case-control study.

SETTING

Research laboratory.

PATIENTS OR OTHER PARTICIPANTS

A total of 20 volunteers with an ACLR (37.0 ± 26.6 months after surgery) and 28 uninjured volunteers.

MAIN OUTCOME MEASURE(S)

We used US to assess anterior femoral cartilage cross-sectional area and thickness (ie, medial, lateral, and intercondylar) in the ACLR and contralateral limbs of participants with ACLR and unilaterally in the reference limbs of uninjured participants.

RESULTS

The ACLR limb presented with greater anterior femoral cartilage cross-sectional area (96.68 ± 22.68 mm²) than both the contralateral (85.69 ± 17.57 mm², t₁₉ = 4.47; P < .001) and uninjured (84.62 ± 15.89 mm², t₄₆ = 2.17; P = .04) limbs. The ACLR limb presented with greater medial condyle thickness (2.61 ± 0.61 mm) than both the contralateral (2.36 ± 0.47 mm, t₁₉ = 2.78; P = .01) and uninjured limbs (2.22 ± 0.40 mm, t₄₆ = 2.69; P = .01) and greater lateral condyle thickness (2.46 ± 0.65 mm) than the uninjured limb (2.12 ± 0.41 mm, t₄₆ = 2.20; P = .03).

CONCLUSIONS

Anterior femoral cartilage cross-sectional area and thickness assessed via US were greater in the ACLR limb than in the contralateral and uninjured limbs. Greater thickness and cross-sectional area may have been due to cartilage swelling or hypertrophy after ACLR, which may affect the long-term health of the joint.

Morphologic and quantitative magnetic resonance imaging of knee articular cartilage for the assessment of post-traumatic osteoarthritis

Orthopedic trauma, such as anterior cruciate ligament (ACL) disruption, is a common source of osteoarthritis in the knee. Magnetic resonance imaging (MRI) is a non-invasive multi-planar imaging modality commonly used to evaluate hard and soft tissues of diarthrodial joints following traumatic injury. The contrast provided by generated images enables the evaluation of bone marrow lesions as well as delamination and degeneration of articular cartilage. We will provide background information about MRI signal generation and decay (T₁ and T₂ values), the utility of morphologic MRI, and the quantitative MRI techniques of T_1ρ , T₂ , and T₂ * mapping, to evaluate subjects with traumatic knee injuries, such as ACL rupture. Additionally, we will provide information regarding the dGEMRIC, sodium, and gagCEST imaging techniques. Finally, the description and utility of newer post hoc analysis techniques, such as texture analysis, will be given. Continued development and refinement of these advanced MRI techniques will facilitate their clinical translation. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:412-423, 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.

Advanced Imaging in Osteoarthritis

Context:

Radiography is widely accepted as the gold standard for diagnosing osteoarthritis (OA), but it has limitations when assessing early stage OA and monitoring progression. While there are improvements in the treatment of OA, the challenge is early recognition.

Evidence Acquisition:

MEDLINE and PubMed as well as professional orthopaedic and imaging websites were reviewed from 2006 to 2016.

Study Design:

Clinical review.

Level of Evidence:

Level 4.

Results:

Magnetic resonance imaging (MRI) can provide the most comprehensive assessment of joint injury and OA with the advantages of being noninvasive and multiplanar with excellent soft tissue contrast. However, MRI is expensive, time consuming, and not widely used for monitoring OA clinically. Computed tomography (CT) and CT arthrography (CTA) can also be used to evaluate OA, but these are also invasive and require radiation exposure. Ultrasound is particularly useful for evaluation of synovitis but not for progression of OA.

Conclusion:

MRI, CT, and CTA are available for the diagnosis and monitoring of OA. Improvement in techniques and decrease in cost can allow some of these modalities to be effective methods of detecting early OA.

Posttraumatic knee osteoarthritis following anterior cruciate ligament injury: Potential biochemical mediators of degenerative alteration and specific biochemical markers

As a common injury, anterior cruciate ligament (ACL) injury is unable to heal itself naturally, which possibly increases knee instability, accelerates the risk of joint degeneration and leads to knee osteoarthritis (OA) in the ACL-injured knee. Thus, ACL reconstruction using an autograft or allograft tendon is proposed to maintain the biomechanical stability of the knee joint. However, previous studies demonstrate that surgical management of ACL reconstruction failed to abrogate the development of OA completely, indicating that biochemical disturbance is responsible for the osteoarthritic changes observed following ACL injury. Inflammatory mediators are elevated subsequent to ACL injury or rupture, inducing matrix metalloproteinase production, proteoglycan degradation, collagen destruction, chondrocyte necrosis and lubricin loss. These potential biochemical mediators may aid in the development of effective biological management to reduce the onset of future posttraumatic OA. Furthermore, during the degenerative process of cartilage, there are a number of cartilage-specific biomarkers, which play a critical step in the loss of structural and functional integrity of cartilage. The present review illustrates several specific biomarkers in the ACL-injured knee joint, which may provide effective diagnostic and prognostic tools for investigating cartilage degenerative progression and future posttraumatic OA of ACL-injured patients.

Femoral bone and cartilage wear is predictable at 0° and 90° in the osteoarthritic knee treated with total knee arthroplasty

PURPOSE

Kinematically aligned total knee arthroplasty (TKA) positions the femoral component at the natural angle and level of the distal (0°) and posterior (90°) joint line. This technique applies referencing guides at 0° and 90° that are adjusted to compensate for wear and kerf and perform resections equal in thickness to the femoral component. Knowing whether femoral bone and cartilage wear is predictable would assist in establishing general guidelines for adjusting the resection level of these two referencing guides. This study tests the hypothesis that femoral bone and cartilage wear is predictable at 0° and 90° in the varus and valgus osteoarthritic knee treated with TKA.

METHODS

The study consists of 205 patients and 208 knees with Kellgren-Lawrence Grade 3 or 4 osteoarthritis and treated with a TKA. Each knee had a narrow slice (2 mm) preoperative 1.5 tesla magnetic resonance image in the sagittal plane. Femoral bone and cartilage wear at 0° and 90° was computed from best-fit circles superimposed on the peripheral boundary of the subchondral bone on the medial and lateral femoral condyles.

RESULTS

Overall, 99.5% of knees had minimal bone wear (<1 mm) at 0° and 90°. In the 74% (154 of 208) of knees with a varus deformity, 92% at 0° and 2 % at 90° had >1 mm cartilage wear on the medial femoral condyle. In the 26% (54 of 208) of knees with a valgus deformity, 78% at 0° and 55% at 90° had ≥1 mm cartilage wear on the lateral femoral condyle.

CONCLUSIONS

As a general guideline, adjustment for femoral bone wear is rarely required when performing kinematically aligned TKA. Most osteoarthritic knees require adjustment of the distal referencing guide to compensate for cartilage wear on the medial femoral condyle in the varus knee and the lateral femoral condyle in the valgus knee. Adjustment of the posterior referencing guide is required in about half of valgus osteoarthritic knees to compensate for lateral cartilage wear at 90°. Knowing that bone wear is rare and cartilage wear is predictable in varus and valgus Kellgren-Lawrence Grade 3 or 4 osteoarthritic knees helps establish general guidelines for adjusting the distal and posterior femoral referencing guides to restore the natural angle and level of the femoral joint lines when performing kinematically aligned TKA with generic instruments.

LEVEL OF EVIDENCE

IV.

Functional imaging in OA: role of imaging in the evaluation of tissue biomechanics

Functional imaging refers broadly to the visualization of organ or tissue physiology using medical image modalities. In load-bearing tissues of the body, including articular cartilage lining the bony ends of joints, changes in strain, stress, and material properties occur in osteoarthritis (OA), providing an opportunity to probe tissue function through the progression of the disease. Here, biomechanical measures in cartilage and related joint tissues are discussed as key imaging biomarkers in the evaluation of OA. Emphasis will be placed on the (1) potential of radiography, ultrasound, and magnetic resonance imaging to assess early tissue pathomechanics in OA, (2) relative utility of kinematic, structural, morphological, and biomechanical measures as functional imaging biomarkers, and (3) improved diagnostic specificity through the combination of multiple imaging biomarkers with unique contrasts, including elastography and quantitative assessments of tissue biochemistry. In comparison to other modalities, magnetic resonance imaging provides an extensive range of functional measures at the tissue level, with conventional and emerging techniques available to potentially to assess the spectrum of preclinical to advance OA.

Quantitative magnetic resonance imaging assessment of cartilage status: a comparison between young men with and without anterior cruciate ligament reconstruction

PURPOSE

To assess the cartilage status of the knee joints using magnetic resonance imaging at least 2 years after anterior cruciate ligament reconstruction (ACLR) in young adult men.

METHODS

Thirty young male patients with unilateral ACLR and 15 age-matched and body mass index--matched healthy men (controls) participated in this study. All participants underwent quantitative magnetic resonance imaging scans. Three-dimensional dual-echo steady-state sagittal images were segmented using solid model software to calculate the mean cartilage thickness, and multi-echo sagittal images were segmented with Siemens software (Siemens, Erlangen, Germany) to determine the T2 relaxation time of each cartilage plate.

RESULTS

There was no statistically significant difference in the mean thickness of each cartilage plate between the ACLR and control groups (P = .9616 for lateral femoral cartilage, P = .5962 for lateral tibial cartilage, P = .9328 for patellar cartilage, P = .9712 for trochlear cartilage, P = .4408 for medial femoral cartilage, and P = .1933 for medial tibial cartilage). The ACLR group had significantly higher T2 values than the control group in the lateral femoral cartilage (P < .001), lateral tibia (P = .0011), trochlea (P = .0028), medial femur (P < .001), and medial tibia (P < .001). In addition, the patella showed no difference in T2 values between the 2 groups (P = .2152). The medial compartment cartilage showed a much higher percentage change in cartilage T2 values in the ACLR group.

CONCLUSIONS

Although no difference in cartilage thickness was detected between the ACLR group and the control group, the mean T2 relaxation time in the ACLR patients was significantly longer than that in control subjects.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

The effects of femoral graft placement on cartilage thickness after anterior cruciate ligament reconstruction

Altered joint motion has been thought to be a contributing factor in the long-term development of osteoarthritis after ACL reconstruction. While many studies have quantified knee kinematics after ACL injury and reconstruction, there is limited in vivo data characterizing the effects of altered knee motion on cartilage thickness distributions. Thus, the objective of this study was to compare cartilage thickness distributions in two groups of patients with ACL reconstruction: one group in which subjects received a non-anatomic reconstruction that resulted in abnormal joint motion and another group in which subjects received an anatomically placed graft that more closely restored normal knee motion. Ten patients with anatomic graft placement (mean follow-up: 20 months) and 12 patients with non-anatomic graft placement (mean follow-up: 18 months) were scanned using high-resolution MR imaging. These images were used to generate 3D mesh models of both knees of each patient. The operative and contralateral knee models were registered to each other and a grid sampling system was used to make site-specific comparisons of cartilage thickness. Patients in the non-anatomic graft placement group demonstrated a significant decrease in cartilage thickness along the medial intercondylar notch in the operative knee relative to the intact knee (8%). In the anatomic graft placement group, no significant changes were observed. These findings suggest that restoring normal knee motion after ACL injury may help to slow the progression of degeneration. Therefore, graft placement may have important implications on the development of osteoarthritis after ACL reconstruction.