Knee cartilage defects in a sample of older adults: natural history, clinical significance and factors influencing change over 2.9 years

In vitro and in vivo evaluation of the osseointegration capacity of a polycarbonate-urethane zirconium-oxide composite material for application in a focal knee resurfacing implant

Currently available focal knee resurfacing implants (FKRIs) are fully or partially composed of metals, which show a large disparity in elastic modulus relative to bone and cartilage tissue. Although titanium is known for its excellent osseointegration, the application in FKRIs can lead to potential stress-shielding and metal implants can cause degeneration of the opposing articulating cartilage due to the high resulting contact stresses. Furthermore, metal implants do not allow for follow-up using magnetic resonance imaging (MRI).To overcome the drawbacks of using metal based FKRIs, a biomimetic and MRI compatible bi-layered non-resorbable thermoplastic polycarbonate-urethane (PCU)-based FKRI was developed. The objective of this preclinical study was to evaluate the mechanical properties, biocompatibility and osteoconduction of a novel Bionate® 75D - zirconium oxide (B75D-ZrO2 ) composite material in vitro and the osseointegration of a B75D-ZrO2 composite stem PCU implant in a caprine animal model. The tensile strength and elastic modulus of the B75D-ZrO2 composite were characterized through in vitro mechanical tests under ambient and physiological conditions. In vitro biocompatibility and osteoconductivity were evaluated by exposing human mesenchymal stem cells to the B75D-ZrO2 composite and culturing the cells under osteogenic conditions. Cell activity and mineralization were assessed and compared to Bionate® 75D (B75D) and titanium disks. The in vivo osseointegration of implants containing a B75D-ZrO2 stem was compared to implants with a B75D stem and titanium stem in a caprine large animal model. After a follow-up of 6 months, bone histomorphometry was performed to assess the bone-to-implant contact area (BIC). Mechanical testing showed that the B75D-ZrO2 composite material possesses an elastic modulus in the range of the elastic modulus reported for trabecular bone. The B75D-ZrO2 composite material facilitated cell mediated mineralization to a comparable extent as titanium. A significantly higher bone-to-implant contact (BIC) score was observed in the B75D-ZrO2 implants compared to the B75D implants. The BIC of B75D-ZrO2 implants was not significantly different compared to titanium implants. A biocompatible B75D-ZrO2 composite approximating the elastic modulus of trabecular bone was developed by compounding B75D with zirconium oxide. In vivo evaluation showed an significant increase of osseointegration for B75D-ZrO2 composite stem implants compared to B75D polymer stem PCU implants. The osseointegration of B75D-ZrO2 composite stem PCU implants was not significantly different in comparison to analogous titanium stem metal implants.

Application of 3D Modeling Software to Preoperative MRI for Prediction of Surface Area of Tissue Applied During Osteochondral Allograft Reconstruction of the Knee

Background

Preoperative magnetic resonance imaging (MRI) is used to estimate the quantity of tissue provided for fresh osteochondral allograft (FOCA) in the knee. Use of 3-dimensional (3D) MRI modeling software for this purpose may improve defect assessment, providing a more accurate estimate of osteochondral allograft tissue required and eliminating the possibility of acquiring an inadequate quantity of tissue for transplant surgery.

Purpose

To evaluate the capacity of damage assessment (DA) 3D MRI modeling software to preoperatively estimate the osteochondral allograft surface area used in surgery.

Study Design

Cohort study (diagnosis); Level of evidence, 2.

Methods

Included were 36 patients who had undergone FOCA surgery to the distal femur. Based on the preoperative MRI scans, the DA software estimated the total surface area of the lesion as well as the surface areas of each subarea of injury: full-thickness cartilage injury (International Cartilage Repair Society [ICRS] grade 4), partial-thickness cartilage injury (ICRS grade 2-3), bone marrow edema, bone loss, and bone cyst. The probability of overestimation of graft tissue areas by the DA software was calculated using a Bayes-moderated proportion, and the relationship between the prediction discrepancy (ie, over- or underestimation) and the magnitude of the DA estimate was assessed using nonparametric local-linear regression.

Results

The DA total surface area measurement overestimated the actual area of FOCA tissue transplanted 81.6% (95% CI, 67.2%-91.4%) of the time, corresponding to a median overestimation of 3.14 cm², or 1.78 times the area of FOCA transplanted. The DA software overestimated the area of FOCA transplanted 100% of the time for defect areas measuring >4.52 cm². For defects <4.21 cm², the maximum-magnitude underestimation of tissue area was 1.45 cm² (on a fold scale, 0.63 times the transplanted area); a plausible heuristic is that multiplying small DA-measured areas of injury by a factor of ∼1.5 would yield an overestimation of the tissue area transplanted most of the time.

Conclusion

The DA 3D modeling software overestimated osteochondral defect size >80% of the time in 36 distal femoral FOCA cases. A policy of consistent but limited overestimation of osteochondral defect size may provide a more reliable basis for predicting the minimum safe amount of allograft tissue to acquire for transplantation.

Patellofemoral articular cartilage damage is associated with poorer patient-reported outcomes following isolated medial patellofemoral ligament reconstruction

PURPOSE

The purpose of this study was to investigate the impact of articular cartilage damage on outcomes following medial patellofemoral ligament (MPFL) reconstruction.

METHODS

Record review identified 160 patients who underwent isolated MPFL reconstruction at a single institution between 2008 and 2016. Patient demographics, patellofemoral articular cartilage status at surgery, and patient anatomical measures from imaging were obtained via chart review. Patients were contacted and outcomes assessed through collection of Norwich Patellar Instability (NPI) score, Knee injury and Osteoarthritis Outcome Score (KOOS), and Marx activity score as well as an assessment for recurrent patellar dislocation. Outcomes of patients with grade 0-II patellofemoral cartilage damage were compared to those of patients with grade III-IV cartilage damage.

RESULTS

One hundred twenty-two patients (76%) with a minimum of one year follow-up were contacted at a mean of 4.8 years post-operatively. A total of 63 patients (52%) had grade III or IV patellofemoral chondral damage at the time of surgery. The majority of the defects was on the medial patella (46 patients-72%) and the mean patellar defect size was 2.8 cm². Among 93 patients who completed patient-reported outcome scores, the 52 with grade III or IV chondral damage reported a significantly poorer KOOS Quality of Life than the 44 patients with grade 0 to II chondral damage (p = 0.041), controlling for patient age, sex, BMI, and anatomical factors.

CONCLUSION

Patients with grade III or IV articular cartilage damage of the patellofemoral joint at the time of MPFL reconstruction demonstrated poorer KOOS knee-related quality of life than patients without grade III or IV articular cartilage damage at a mean of 4.8 years following isolated MPFL reconstruction.

LEVEL OF EVIDENCE

Level II.

Osteochondral Allograft Transplant for Combined Medial and Lateral Patellar Cartilage Lesions: The Osteochondral Wide Lesion (OWL) Technique

Symptomatic articular cartilage injuries are often seen in young active patients and athletes. Magnetic resonance imaging screening examinations have frequently identified such lesions in athletic patients. Patellofemoral chondral defects were previously identified as the most common knee cartilage lesion in high-level athletes. Chondral defects measuring 2 cm² or greater and complex cartilage defects involving bone loss are ideally replaced with fresh osteochondral allograft. We describe a technique indicated for patients with symptomatic and recurrent anterior knee pain associated with osteochondral patellar defects including the lateral and medial patellar facets. Patients who have undergone previous interventions, including membrane techniques, microfracture, or autologous chondral transplantation, without clinical benefit are also eligible to undergo osteochondral allograft transplantation for combined medial and lateral patellar cartilage lesions, that is, the osteochondral wide lesion (OWL) technique.

Knorpelersatzverfahren und Regeneration am Knie- und Hüftgelenk

Die operative Therapie von Knorpelschäden am Kniegelenk hat sich in den letzten Jahren von vorsichtigen Anfängen mit innovativen Therapieansätzen zu einem festen und etablierten Baustein der gelenkerhaltenden Therapie entwickelt. Hingegen hat sich am Hüftgelenk erst in den letzten 10 Jahren, basierend auf einem erweiterten Verständnis grundlegender mechanischer Pathomechanismen, die gelenkerhaltende Hüftchirurgie und insbesondere die Knorpeltherapie etabliert. Der Beitrag stellt die zur Verfügung stehenden Techniken vor.

Does Gender Influence Outcome in Cartilage Repair Surgery? An Analysis of 4,968 Consecutive Patients from the German Cartilage Registry (Knorpel Register DGOU)

The goal was to examine gender differences of patient characteristics and outcome after cartilage repair based on a collective of nearly 5,000 patients. Patient characteristics, accompanying therapies, and outcome (Knee Injury and Osteoarthritis Outcome Score [KOOS], reoperations, patient satisfaction) of 4,986 patients of the German cartilage register DGOU were assessed by t test for possible gender differences. P values <0.05 were considered statistically significant. Women were older than men (38.07 ± 12.54 vs. 26.94 ± 12.394 years, P = 0.002), more often preoperated (0.30 ± 0.63 vs. 0.24 ± 0.55, P = 0.001), and had a longer symptom duration (25.22 ± 41.20 vs. 20.67 ± 35.32 months, P < 0.001). Men had greater mean leg axis malalignment than women (3.24° ± 3.26° vs. 2.67° ± 3.06°, P < 0.001), less favorable meniscal status (P = 0.001), worse defect stage (P = 0.006), and a more severely damaged corresponding articular surface (P = 0.042). At baseline (59.84 ± 17.49 vs. 52.10 ± 17.77, P < 0.001), after 6 months (72.83 ± 15.56 vs. 66.56 ± 17.66, P < 0.001), after 12 months (77.88 ± 15.95 vs. 73.07 ± 18.12, P < 0.001), and after 24 months (79.311 ± 15.94 vs. 74.39 ± 18.81, P < 0.001), men had better absolute KOOS values, but women had better relative KOOS increases 6 months (14.59 ± 17.31 vs. 12.49 ± 16.3, P = 0.005) as well as 12 months postoperatively (20.27 ± 18.6 vs. 17.34 ± 17.79, P = 0.001) compared with preoperatively, although 12 and 24 months postoperatively they were subjectively less satisfied with the outcome (P < 0.001) and had a higher reintervention rate at 24 months (0.17 ± 0.38 vs. 0.12 ± 0.33, P = 0.008). In summary, the present work shows specific gender differences in terms of patient characteristics, defect etiology, defect localization, concomitant therapy, and the choice of cartilage repair procedure. Unexpectedly, contrary to the established scientific opinion, it could be demonstrated that women show relatively better postoperative KOOS increases, despite a higher revision rate and higher subjective dissatisfaction.

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.

Symptom Chronicity and Tobacco Use: Differences in Athletic and Nonathletic Candidates for Cartilage Surgery

OBJECTIVE

To determine whether there are differences in symptomatic knee cartilage defects and rates of tobacco use among age-matched athletes versus nonathletes undergoing initial arthroscopic knee surgery who meet demographic and radiographic criteria for cartilage restoration surgery.

DESIGN

Age-matched athletes (n = 186) and nonathletes (n = 159) age 40 or less with a body mass index (BMI) of 35 kg/m² or less (mean 26.8 SD 4.1) and <50% joint space narrowing on weight-bearing radiographs were included. All patients had a symptomatic Outerbridge grade 2 or higher cartilage defect visualized during knee arthroscopy. Relationship between athletic status and chronicity of knee symptoms prior to surgery and tobacco use status, cartilage defect Outerbridge grade, size, and location at time of surgery were characterized.

RESULTS

Nonathletes were more likely to smoke (P < 0.001) and had higher BMI (P = 0.005). Duration of symptoms prior to surgery was shorter among athletes (P < 0.001). Grade 4 defects were equally prevalent (P = 0.96) as were multicompartment grade 3-4 lesions (P = 0.12). Mean grade 3-4 defect size was similar in lateral (P = 0.96) and medial compartments (P = 0.82). There was a trend toward larger anterior compartment defects in nonathletes (P = 0.07).

CONCLUSIONS

Among age-matched athletes and nonathletes with symptomatic cartilage defects who meet demographic criteria for cartilage restoration, nonathletes were more likely to smoke and have a longer duration of symptoms prior to treatment. Athletes tended to present earlier but with similar size defects compared to nonathletes, supporting accelerated treatment of defects in athletes and caution toward allowing continued athletic participation in patients with known cartilage defects.

Knee Cartilage Defect Characteristics Vary among Symptomatic Recreational and Competitive Scholastic Athletes Eligible for Cartilage Restoration Surgery

OBJECTIVE

To determine whether there are differences by sport or competitive level in symptomatic knee cartilage defects among recreational, high school, or collegiate competitive athletes undergoing initial arthroscopic knee surgery who meet criteria for cartilage restoration surgery.

DESIGN

Three hundred recreational (n = 172) and high school or collegiate competitive athletes (n = 128) younger than 40 years and body mass index (BMI) <35 kg/m² (63% male, mean age 24.3 years, SD 7.1; mean BMI 25.7 kg/m², SD 3.7) with Outerbridge grade 2 or higher symptomatic cartilage defects who underwent arthroscopic knee surgery were identified. The independent relationship between sporting activity or competitive level and cartilage defect location, size, severity, and symptom chronicity were assessed by multivariate regression analysis.

RESULTS

Full-thickness defects were present in 24% of competitive athletes and 31% of recreational athletes (P = 0.21). There was a trend toward an independent association with competitive level and high-grade (3 or 4) multicompartment disease (adjusted odds ratio [aOR] 3.99, 95% confidence interval 0.84-18.8; P = 0.08) or isolated anterior compartment defects (aOR 2.00, 95% CI 0.86-4.62, P = 0.10) but not isolated medial or lateral defects. High-grade defect size was similar among recreational and competitive athletes (P = 0.71). High-grade lateral defect prevalence differed by sport (running 24%, basketball 23%, soccer 18%, football 5%; P = 0.02) but not medial or anterior defect prevalence.

CONCLUSIONS

Among recreational and high school or collegiate competitive athletes with symptomatic cartilage defects who meet criteria for cartilage restoration, competitive athletes may have higher risk of high-grade anterior and multicompartment defects but no difference in defect size.

Prevalence of patellar chondropathy on 3.0 T magnetic resonance imaging

Objective

To establish the prevalence of patellar chondropathy using 3T magnetic resonance imaging (MRI) and to correlate the findings with individual features such as gender, age, and body mass index.

Materials and Methods

Data consisted of collecting 3T MRIs of patients’ knees obtained between October 2016 and September 2017, comprising a period of 12 months. These MRIs were assessed by an experienced musculoskeletal radiologist who confirmed the presence of patellar chondropathy and, when present, rated the finding into the four grades ascribed by the International Cartilage Repair Society.

Results

A total number of 291 patients were assessed during the period with 389 MRI scans. Of those patients, 308 (79.2%) were diagnosed with patellar chondropathy, while 81 (20.8%) were not. Chondropathy was more prevalent in the female gender, in subjects above 40 years of age, and in obese patients. When the results were weighed in International Cartilage Repair Society classification, the milder grades (1 and 2) were seen in younger men (< 30 years of age), while the more severe grades (3 and 4) were mostly present in females, those above 40 years of age, and in obese patients.

Conclusion

There was a high prevalence of patellar chondropathy in patients who had undergone high-field knee MRIs (79.2%), being highest in the female gender and in subjects above 40 years of age. The most prevalent group was graded as 4 by the International Cartilage Repair Society classification.

Quantification of hip effusion-synovitis and its cross-sectional and longitudinal associations with hip pain, MRI findings and early radiographic hip OA

BACKGROUND

Hip effusion-synovitis may be relevant to osteoarthritis (OA) but is of uncertain etiology. The aim of this study was to describe the cross-sectional and longitudinal associations of hip effusion-synovitis with clinical and structural risk factors of OA in older adults.

METHODS

One hundred ninety-six subjects from the Tasmanian Older Adult Cohort (TASOAC) study with a right hip STIR (Short T1 Inversion Recovery) Magnetic Resonance Imaging (MRI) on two occasions were included. Hip effusion-synovitis CSA (cm2) was assessed quantitatively. Hip pain was determined by WOMAC (Western Ontario and McMaster Universities Osteoarthritis) while hip bone marrow lesions (BMLs), cartilage defects (femoral and/or acetabular) and high cartilage signal were assessed on MRI. Joint space narrowing (0-3) and osteophytes (0-3) were measured on x-ray using Altman's atlas.

RESULTS

Of 196 subjects, 32% (n = 63) had no or a small hip effusion-synovitis while 68% (n = 133) subjects had a moderate or large hip effusion-synovitis. Both groups were similar but those with moderate or large hip effusion-synovitis were older, had higher BMI and more hip pain. Cross-sectionally, hip effusion-synovitis at multiple sites was associated with presence of hip pain [Prevalence ratio (PR):1.42 95%CI:1.05,1.93], but not with severity of hip pain. Furthermore, hip effusion-synovitis size associated with femoral defect (βeta:0.32 95%CI:0.08,0.56). Longitudinally, and incident hip cartilage defect (PR: 2.23 95%CI:1.00, 4.97) were associated with an increase in hip effusion-synovitis CSA. Furthermore, independent of presence of effusion-synovitis, hip BMLs predicted incident (PR: 1.62 95%CI: 1.13, 2.34) and worsening of hip cartilage defects (PR: 1.50 95%CI: 1.20, 1.86). While hip cartilage defect predicted incident (PR: 1.11 95%CI: 1.03, 1.20) and worsening hip BMLs (PR: 1.16 95%CI: 1.04, 1.30).

CONCLUSIONS

Hip effusion-synovitis at multiple sites (presumably reflecting extent) may be associated with hip pain. Hip BMLs and hip cartilage defects are co-dependent and predict worsening hip effusion-synovitis, indicating causal pathways between defects, BMLs and effusion-synovitis.

Association of baseline and change in tibial and femoral cartilage thickness and development of widespread full-thickness cartilage loss in knee osteoarthritis - data from the Osteoarthritis Initiative

OBJECTIVE

To investigate whether baseline cartilage thickness and its longitudinal change are associated with incident widespread full-thickness cartilage loss (wsFTCL) in knee osteoarthritis, and whether there are optimal cut-off values for predicting wsFTCL.

METHODS

Central medial tibial (cMT) and femoral (cMF) cartilage were assessed using quantitative magnetic resonance imaging data from the Osteoarthritis Initiative cohort (N = 600 knees). Cartilage thickness was measured at baseline and 12 months. wsFTCL was defined semi-quantitatively (scores 2 and 3 from the MRI Osteoarthritis Knee Score) and its incidence at 24 months recorded. Logistic regression was used to determine the odds of developing wsFTCL for baseline and for each 0.1 mm decrease in cartilage thickness. Cut-off values were investigated using the minimal-p method and area under the Receiver Operating Characteristic curves (AUC).

RESULTS

Incident wsFTCL was observed in 66 (12%) and 73 (14%) knees in cMT and cMF, respectively. Lower baseline cMT and cMF cartilage thickness values were associated with wsFTCL (OR = 1.20; 95% CI: 1.11, 1.28 and OR = 1.15; 95% CI: 1.06 to 1.24, respectively). Optimal cut-off AUCs for the tibia and femur were 0.64 (0.57-0.70) and 0.63 (0.57-0.69), respectively. Longitudinal decrease in femoral, but not tibial, cartilage thickness was associated with incident wsFTCL (OR = 1.77; 95% CI: 1.30 to 2.40); optimal cut-off AUC 0.65 (95% CI: 0.58-0.72).

CONCLUSION

Lower baseline cMT and baseline/change (decrease) over 12 months in cMF cartilage thickness were associated with incident, location-specific, wsFTCL at 24 months. Optimal cut-off values were relatively low and of uncertain utility for predicting incident wsFTCL.

The effects of weight loss on imaging outcomes in osteoarthritis of the hip or knee in people who are overweight or obese: a systematic review

OBJECTIVE

To evaluate the structural effects of weight loss on hip or knee osteoarthritis (OA) and to summarize which structural joint pathologies have been examined and the evidence for the outcome measurement instruments applied.

DESIGN

Based on a pre-specified protocol (available: PROSPERO CRD42017065263), we conducted a systematic search of the bibliographic databases, Medline, Embase and Web of Science identifying longitudinal articles reporting the effects of weight loss on structural imaging outcomes in OA of the hip or knee in people who are overweight or obese.

RESULTS

From 1625 potentially eligible records, 14 articles (from 6 cohorts) were included. 2 cohorts were derived from RCTs. Evaluated pathologies were: articular cartilage (n = 7), joint space width (n = 3), bone marrow lesions (n = 5), synovitis (n = 2), effusion (n = 1), meniscus (n = 3), bone marrow density (n = 1) and infrapatellar fat pad (IPFP; n = 2). Cartilage showed conflicting results when evaluating cartilage thickness by direct thickness measurements. Compositional dGEMRIC and T2 mapping measures in early knee OA showed trends towards reduced cartilage degeneration. Joint space width on conventional radiographs showed no change. Weight loss reduced the size of the IPFP. Synovitis and effusion were not affected. Following weight loss DXA showed bone loss at the hip.

CONCLUSION

We did not find consistent evidence of the effects of weight loss on OA structural pathology in people who are overweight or obese. There is a need to achieve consensus on which structural pathologies and measurements to apply in weight loss and OA research.

Medial compartment defects progress at a more rapid rate than lateral cartilage defects in older adults with minimal to moderate knee osteoarthritis (OA): data from the OA initiative

PURPOSE

To determine: (1) rates and risk factors for progression of lateral and medial full-thickness cartilage defect size in older adults without severe knee osteoarthritis (OA), and (2) whether risk factors for defect progression differ for knees with Kellgren-Lawrence OA grade 3 (moderate) OA versus grades 0-2 (none to mild) OA.

METHODS

Three-hundred and eighty adults enrolled in the Osteoarthritis Initiative were included (43% male, mean age 63.0 SD 9.2 years). Ethical approval was obtained at all study sites prior to enrollment. All participants had full-thickness tibial or weight-bearing femoral condylar cartilage defects on baseline knee MRIs. Baseline OA grade was KL grade 3 in 71.3% and grades 0-2 in 21.7% of participants. Repeat MRIs were obtained at a minimum 2-year follow-up. Independent risk of progression in defect size due to demographic factors, knee alignment, OA grade, knee injury and surgery history, and baseline knee symptoms was determined by multivariate Cox proportional hazards and linear regression modeling.

RESULTS

The average increase in defect size over 2 years for lateral defects was 0.18 cm² (SD 0.60) and for medial defects was 0.49 cm² (SD 1.09). Independent predictors of medical defect size progression were bipolar defects (beta 0.47 SE 0.08; p < 0.001), knee varus (per degree, beta 0.08 SE 0.03; p = 0.02) and increased weight (per kg, beta = 0.01 SE 0.004; p = 0.01). Independent predictors for lateral defect progression were larger baseline defect size (per 1.0 cm², beta 0.14 SE 0.03; p < 0.001) and tibial sided defects (beta 0.12 SE 0.04) and degrees valgus (per degree, beta 0.04 SE 0.01; p = 0.001).

CONCLUSIONS

Medial compartment full-thickness defects progress at a more rapid rate than lateral defects in older adults with minimal to moderate OA. Medial defect progression was greatest for bipolar defects in heavier adults with varus knees. Lateral defect progression was greatest for large tibial-sided defects in adults with valgus knees.

LEVEL OF EVIDENCE

II.

Biomechanical Evidence on Anterior Cruciate Ligament Reconstruction

Objective  Anterior cruciate ligament (ACL) reconstruction is recommended in athletes with high physical demands. Several techniques are used in reconstruction; however, the most relevant question still is the best biomechanical positioning for the graft. The present study aimed to analyze the biomechanical effect of the position of bone tunnels on load distribution and joint kinetics, as well as the medium-term functional outcomes after ACL reconstruction.

Methods  A biomechanical study using a finite element model of the original knee (without anterior cruciate ligament rupture) and reconstruction of the ACL (neoACL) was performed in four combinations of bone tunnel positions (central femoral-central tibial, anterior femoral-central tibial, posterosuperior femoral-anterior tibial, and central femoral-anterior tibial) using the same type of graft. Each neo-ACL model was compared with the original knee model regarding cartilaginous contact pressure, femoral and meniscal rotation and translation, and ligamentous deformation.

Results  No neo-ACL model was able to fully replicate the original knee model. When the femoral tunnel was posteriorly positioned, cartilage pressures were 25% lower, and the mobility of the meniscus was 12 to 30% higher compared with the original knee model. When the femoral tunnel was in the anterior position, internal rotation was 50% lower than in the original knee model.

Conclusion  Results show that the femoral tunnel farther from the central position appears to be more suitable for a distinct behavior regarding the intact joint. The most anterior position increases rotational instability.

Fiber Reinforced Cartilage ECM Functionalized Bioinks for Functional Cartilage Tissue Engineering

Focal articular cartilage (AC) defects, if left untreated, can lead to debilitating diseases such as osteoarthritis. While several tissue engineering strategies have been developed to promote cartilage regeneration, it is still challenging to generate functional AC capable of sustaining high load-bearing environments. Here, a new class of cartilage extracellular matrix (cECM)-functionalized alginate bioink is developed for the bioprinting of cartilaginous tissues. The bioinks are 3D-printable, support mesenchymal stem cell (MSC) viability postprinting and robust chondrogenesis in vitro, with the highest levels of COLLII and ACAN expression observed in bioinks containing the highest concentration of cECM. Enhanced chondrogenesis in cECM-functionalized bioinks is also associated with progression along an endochondral-like pathway, as evident by increases in RUNX2 expression and calcium deposition in vitro. The bioinks loaded with MSCs and TGF-β3 are also found capable of supporting robust chondrogenesis, opening the possibility of using such bioinks for direct "print-and-implant" cartilage repair strategies. Finally, it is demonstrated that networks of 3D-printed polycaprolactone fibers with compressive modulus comparable to native AC can be used to mechanically reinforce these bioinks, with no loss in cell viability. It is envisioned that combinations of such biomaterials can be used in multiple-tool biofabrication strategies for the bioprinting of biomimetic cartilaginous implants.

Lateral cartilage defects and medial subchondral surface ratio are associated with knee-related disability

We sought to determine the relationship between (i) full-thickness cartilage defects and tibiofemoral subchondral surface ratio (SSR) and (ii) disability and quality of life in patients with mild radiographic osteoarthritis (OA) (Kellgren-Lawrence grade 2) or without radiographic OA (Kellgren-Lawrence grades 0 or 1)? A total of 642 participants from the Osteoarthritis Initiative (OAI) with baseline knee MRIs and a Kellgren-Lawrence grade 2 or less on both bilateral screening radiographs were included. The independent relationship was assessed between (i) full-thickness cartilage defect presence and tibiofemoral SSR and (ii) Knee Injury and Osteoarthritis Outcome Score (KOOS) quality of life (QOL), KOOS function in sports and recreation (KOOS-sport/rec), and Western Ontario and McMaster Universities Arthritis Index (WOMAC) disability score after adjustment for relevant confounders with multivariate regression modeling. The prevalence of medial full-thickness defects was 10.4% (67/642) and lateral was 18.1% (116/642). Lateral defect presence was associated with worse KOOS-QOL (beta -3.61 SE 1.04; p = 0.001), KOOS-sport/rec (beta -4.70 SE 1.38; p = 0.001) and WOMAC-disability scores (beta 0.02 SE 0.01; p = 0.001); these associations were not influenced by defect size. A larger medial compartment SSR was associated with worse KOOS-QOL (beta -27.20 SE 6.80; p < 0.001), KOOS-sports/rec (beta -22.30 SE 9.01; p = 0.01) and WOMAC-disability scores (beta 0.16 SE 0.04; p < 0.001). In older adults with little to no radiographic osteoarthritis, lateral full-thickness cartilage defects, irrespective of size, and a larger medial compartment tibiofemoral SSR are potential sources of knee-related symptoms that are not appreciated on standard radiographs. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:378-385, 2019.

Role of full-thickness cartilage defects in knee osteoarthritis (OA) incidence and progression: Data from the OA Initiative

The purpose of this study is to determine whether full-thickness tibiofemoral cartilage defects are predictive of incident radiographic OA, progression of radiographic OA, and progression to severe radiographic OA. Participants in the OA Initiative (n = 1317, 38.1% male, mean age 60.9 years SD 9.2) with baseline MRIs and Kellgren-Lawrence (KL) OA grade 0-3 (none to moderate OA) were included. All participants had follow-up radiographs at mean 4.9 years (max 8.0). The effect of full-thickness defect presence, size, and location on risk of incident OA (KL grade 2+), overall progression of OA (increase in KL grade 1+ points), or compartment-specific OA progression was assessed with Cox proportional hazards modeling with adjustment for demographic factors, weight, and knee alignment. The yearly incidence of tibiofemoral OA was 0.3% (CI 0.2-0.4%); defect presence, size, and location were not associated with incident OA risk. The yearly rate of OA progression was 3.8% in participants without tibiofemoral full-thickness defects, 6.7% with medial defects, and 6.3% with lateral defects. Medial bipolar (kissing) lesions were an independent risk factor for OA progression as well as medial compartment progression. Lateral tibial-sided full-thickness defects increased risk of lateral progression (increase in lateral OARSI grade). In older adults, isolated full-thickness cartilage defects do not increase short-term risk of incident OA. However, in the setting of preexisting mild or moderate OA, medial bipolar (kissing) defects increase risk of overall OA progression (KL grade) as well as progression of medial compartment OA. Lateral tibial defects increase risk of lateral compartment OA progression. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res.

Association of childhood adiposity measures with adulthood knee cartilage defects and bone marrow lesions: a 25-year cohort study

OBJECTIVE

To describe the associations between childhood adiposity measures and adulthood knee cartilage defects and bone marrow lesions (BMLs) measured 25 years later.

METHODS

327 participants from the Australian Schools Health and Fitness Survey (ASHFS) of 1985 (aged 7-15 years) were followed up 25 years later (aged 31-41 years). Childhood measures (weight, height and skinfolds) were collected in 1985. Body mass index (BMI), overweight status and fat mass were calculated. Participants underwent 1.5 T knee magnetic resonance imaging (MRI) during 2008-2010, and cartilage defects and BMLs were scored from knee MRI scans. Log binomial regressions were used to examine the associations.

RESULTS

Among 327 participants (47.1% females), 21 (6.4%) were overweight in childhood. Childhood adiposity measures were associated with the increased risk of adulthood patellar cartilage defects (Weight relative risk (RR) 1.05/kg, 95% confidence interval (CI) 1.01-1.09; BMI 1.10/kg/m², 1.01-1.19; Overweight 2.22/yes, 1.21-4.08; fat mass 1.11/kg, 1.01-1.22), but not tibiofemoral cartilage defects. Childhood adiposity measures were not significantly associated with adulthood knee BMLs except for the association between childhood overweight status and adulthood patellar BMLs (RR 2.87/yes, 95% CI 1.10-7.53). These significant associations persisted after adjustment for corresponding adulthood adiposity measure.

CONCLUSION

Childhood adiposity measures were associated with the increased risk of adulthood patellar cartilage defects and, to a lesser extent, BMLs, independent of adulthood adiposity measures. These results suggest that adiposity in childhood has long-term effects on patellar structural abnormalities in young adults.

Osteochondral Allograft Transplantation and Opening Wedge Tibial Osteotomy: Clinical Results of a Combined Single Procedure

Objective To evaluate the outcome of patients who have undergone simultaneous osteotomy and osteochondral allograft (OCA) transplantation. Our hypothesis is that use of high tibial osteotomy and fresh OCA in a combined procedure is safe and effective without increasing morbidity in comparison to OCA alone. Design A case series of 17 patients underwent tibial osteotomy and simultaneous OCA during a single surgery. Osteotomy was indicated when axial alignment was within the affected compartment. Patients had a minimum of 2 years of follow-up after surgery. The mean graft size was 8.7 cm², with 82% located on the medial femoral condyle alone and 18% involving the medial femoral condyle and one or more other sites. Data collection included demographics, osteotomy correction, graft site(s) and area, and clinical evaluation. Failure was defined as conversion to arthroplasty. Results Two of 17 patients (12%) failed at a mean of 9.3 years. The remaining 15 patients (88%) had intact allografts with mean survival of 8.1 years (SD 3.3). Five patients (29%) had an additional procedure, all undergoing osteotomy hardware removal. Of those with surviving allografts, mean pain and function scores improved significantly from the preoperative to postoperative assessment and International Knee Documentation Committee total scores improved significantly from 40.9 ± 15.4 preoperative to 75.5 ± 24.0 at latest follow-up ( P = 0.003); 92% of patients were satisfied with the results of the surgery. No postoperative complications occurred. Conclusion Combining high tibial osteotomy and OCA in properly selected patients is safe and effective.

Sagittal plane walking patterns are related to MRI changes over 18-months in people with and without mild-moderate hip osteoarthritis

The purpose was to evaluate the association of sagittal plane gait mechanics with MRI changes in the hip joint over 18-months. Subjects with and without radiographic hip OA (n = 57) underwent MRI at baseline and 18 months for grading of cartilage lesions, bone marrow lesions (BML), cysts, and labral tears. 3D gait analyses at baseline were used for sagittal plane hip kinematics and kinetics during the stance phase. Subjects were classified as progressors or non-progressors based on increase in any MRI OA parameter. Multivariate ANOVA were used for differences in sagittal gait parameters between progressors and non-progressors at baseline while adjusting for age. Logistic regression was used to estimate the probability of being classified as a progressor or non-progressor with increasing hip flexion while adjusting for age, BMI, sex, and presence of radiographic hip OA. Of the 57, 35 were classified as non-progressors and 22 were classified as progressors. At baseline, the progressors walked with 4.5° greater hip flexion during early stance (p = 0.021) and 3.5° lesser hip extension in late stance that was nearly significant (p = 0.059). Walking with greater hip flexion at baseline was associated with a greater risk of increase in MRI defined structural changes in the hip joint (Odds Ratio = 1.1, p = 0.038). Greater hip flexion during walking was associated with a risk of structural progression of hip OA. The results may guide future interventions to alter the walking patterns and slow structural hip OA progression.© 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:1472-1477, 2018.

Associations Between Knee Effusion-synovitis and Joint Structural Changes in Patients with Knee Osteoarthritis

Objective.

To describe the associations between effusion-synovitis and joint structural abnormalities in patients with knee osteoarthritis (OA) over 24 months.

Methods.

A posthoc analysis using data from a randomized controlled trial in 413 patients with symptomatic OA (aged 63 ± 7 yrs, 208 women). Knee effusion-synovitis volume and score, cartilage defects, cartilage volume, and bone marrow lesions (BML) were assessed using magnetic resonance imaging. Joint space narrowing (JSN) and osteophytes were assessed using radiograph. Least significant change criterion was used to define change in effusion-synovitis volume. Knee symptoms were assessed by Western Ontario and McMaster University OA Index. Multivariable linear/logistic regression and multilevel generalized mixed-effects models were used in longitudinal analyses.

Results.

Total effusion-synovitis volume increased modestly from baseline (8.0 ± 8.5 ml) to followup (9.0 ± 10.5 ml). Baseline BML, cartilage defect, JSN, and osteophyte scores were positively associated with change in effusion-synovitis volume (p < 0.05). Baseline cartilage defects and JSN were also associated with change in effusion-synovitis score (p < 0.05). However, neither baseline effusion-synovitis score nor volume consistently predicted change in the above structures except cartilage volume. In the mixed-effects models, knee effusion-synovitis was positively associated with BML (volume: β = 1.19 ml/grade; score: OR = 1.75/grade) and cartilage defects (volume: β = 1.87 ml/grade; score: OR = 2.22/grade), while negatively associated with cartilage volume loss. Change in effusion-synovitis volume was positively correlated with changes in knee pain and stiffness scores (p < 0.05).

Conclusion.

Knee cartilage and subchondral bone abnormalities predicted change in effusion-synovitis, but effusion-synovitis did not predict knee structural changes. These findings suggest that synovial inflammation is likely the result of joint structural abnormalities in established OA. ClinicalTrials.gov identifier: NCT01176344. Australian New Zealand Clinical Trials Registry: ACTRN12610000495022.

Brief Report: Partial- and Full-Thickness Focal Cartilage Defects Contribute Equally to Development of New Cartilage Damage in Knee Osteoarthritis: The Multicenter Osteoarthritis Study

OBJECTIVE

To determine the risk of incident cartilage damage at follow-up in subregions that are undamaged at baseline, by comparing tibiofemoral joint compartments with a baseline focal partial-thickness or full-thickness cartilage defect against compartments without any baseline cartilage damage, in knees with and those without radiographic osteoarthritis (OA).

METHODS

We included participants in the Multicenter Osteoarthritis Study for whom there were semiquantitative magnetic resonance imaging readings at baseline and at 30 months. We estimated the risk of incident cartilage defects developing in tibiofemoral compartments with prevalent partial-thickness and full-thickness cartilage defects in only one subregion within the compartment, using tibiofemoral compartments with no baseline cartilage defects as a referent. Logistic regression with generalized estimating equations was used for all analyses, with adjustments for confounders.

RESULTS

A total of 374 compartments (359 knees) were included, and 140 knees (39%) had radiographic OA. Compared to compartments with no baseline cartilage defects, those with partial-thickness (adjusted odds ratio 1.62 [95% confidence interval 1.06-2.47]) and full-thickness (adjusted odds ratio 1.92 [95% confidence interval 1.00-3.66]) cartilage defects in a subregion had a higher risk of incident cartilage defects in other subregions in the same compartment.

CONCLUSION

Prevalent focal cartilage defects, regardless of defect depth, in a single subregion within a tibiofemoral joint compartment increase the risk of developing new cartilage damage in other subregions of the same compartment for middle-aged to elderly persons with or at high risk of knee OA.

Altered gait mechanics and elevated serum pro-inflammatory cytokines in asymptomatic patients with MRI evidence of knee cartilage loss

OBJECTIVE

To test if sagittal plane gait mechanics parameters and serum inflammation levels differ between healthy asymptomatic subjects and asymptomatic subjects with magnetic resonance imaging (MRI) evidence of cartilage loss.

DESIGN

Gait mechanics and resting serum tumor necrosis factor-α (TNFα) concentrations were measured for two groups of asymptomatic subjects recruited for a previous study: Pre-Osteoarthritis (OA) subjects had MRI evidence of partial- or full-thickness knee cartilage loss in at least one compartment (n = 52 (30 female), 1.7 ± 0.1 m, 85.3 ± 18.9 kg, 44 ± 11 years); Control subjects had no MRI features of cartilage loss, osteophytes, bone marrow lesions, nor meniscal pathology in either knee (n = 26 (13 female), 1.7 ± 0.1 m, 74.6 ± 14.9 kg, 34 ± 10 years). Discrete measures of sagittal plane gait kinematics and kinetics were compared between subject groups and adjusted for age and body mass index (BMI) using analysis of covariance (ANCOVA). Serum TNFα concentrations were compared between groups using bootstrap t-test.

RESULTS

The Pre-OA group had less extended knees (P = 0.021) and decreased maximum external knee extension moment (P = 0.0062) in terminal stance during gait, as well as increased resting serum TNFα concentration (P = 0.040) as compared to Control subjects. There were no group differences in heel strike flexion angle (P = 0.14), in maximum knee flexion moment (P = 0.91), nor in first peak knee adduction moment (KAM) (post-hoc analysis, P = 0.39).

CONCLUSIONS

The finding that asymptomatic subjects with cartilage loss had gait and inflammatory characteristics similar to those previously reported in symptomatic OA patients supports the idea that there are specific mechanical and biological factors that precede the onset of knee pain in the pathogenesis of OA.

How Are Obesity and Body Composition Related to Patellar Cartilage? A Systematic Review

Objective.

The aim of this review was to systematically examine the evidence for an association between measures of obesity [weight and body mass index (BMI)] and body composition (fat mass and fat-free mass) and patellar cartilage, assessed using magnetic resonance imaging.

Methods.

Three electronic databases (MEDLINE, EMBASE, and CINAHL) were searched up to April 2016 using full text and MeSH terms to identify studies examining the associations between obesity and body composition, and patellar cartilage. Two independent reviewers extracted the data and assessed the methodological quality of included studies.

Results.

Seventeen studies were included: 5 cross-sectional, 10 cohort studies measuring outcomes at 2 timepoints, and 2 longitudinal studies assessing outcome only at the timepoint. Eleven studies were of high or moderate quality. In asymptomatic middle-aged adults, elevated body weight and BMI were systematically associated with worse patellofemoral cartilage scores. There was more consistent evidence for patellar cartilage defects than patellar cartilage volume, particularly in women. Increased BMI was also consistently associated with increased cartilage loss in longitudinal studies, although not all attained statistical significance.

Conclusion.

There is a need for more high-quality research to confirm these findings and to better explain the relative contributions of metabolic and biomechanical factors to the initiation of patellofemoral osteoarthritis, to devise effective strategies to manage this common and disabling condition.

MRI-based hip cartilage measures in osteoarthritic and non-osteoarthritic individuals: a systematic review

Osteoarthritis is a common hip joint disease, involving loss of articular cartilage. The prevalence and prognosis of hip osteoarthritis have been difficult to determine, with various clinical and radiological methods used to derive epidemiological estimates exhibiting significant heterogeneity. MRI-based methods directly visualise hip joint cartilage, and offer potential to more reliably define presence and severity of osteoarthritis, but have been underused. We performed a systematic review of MRI-based estimates of hip articular cartilage in the general population and in patients with established osteoarthritis, using MEDLINE, EMBASE and SCOPUS current to June 2016, with search terms such as ‘hip’, ‘femoral head’, ‘cartilage’, ‘volume’, ‘thickness’, ‘MRI’, etc. Ultimately, 11 studies were found appropriate for inclusion, but they were heterogeneous in osteoarthritis assessment methodology and composition. Overall, the studies consistently demonstrate the reliability and potential clinical utility of MRI-based estimates. However, no longitudinal data or reference values for hip cartilage thickness or volume have been published, limiting the ability of MRI to define or risk-stratify hip osteoarthritis. MRI-based techniques are available to quantify articular cartilage signal, volume, thickness and defects, which could establish the sequence and rate of articular cartilage changes at the hip that yield symptomatic osteoarthritis. However, prevalence and rates of progression of hip osteoarthritis have not been established in any MRI studies in the general population. Future investigations could fill this important knowledge gap using robust MRI methods in population-based cross-sectional and longitudinal studies.

A new MRI grading system for chondromalacia patellae

Background Chondromalacia patellae is a very common disorder. Although magnetic resonance imaging (MRI) is widely used to investigate patellar cartilage lesions, there is no descriptive MRI-based grading system for chondromalacia patellae. Purpose To propose a new MRI grading system for chondromalacia patellae with corresponding high resolution images which might be useful in precisely reporting and comparing knee examinations in routine daily practice and used in predicting natural course and clinical outcome of the patellar cartilage lesions. Material and Methods High resolution fat-saturated proton density (FS PD) images in the axial plane with corresponding T2 mapping images were reviewed. A detailed MRI grading system covering the deficiencies of the existing gradings has been set and presented on these images. Two experienced observers blinded to clinical data examined 44 knee MR images and evaluated patellar cartilage changes according to the proposed grading system. Inter- and intra-rater validity testing using kappa statistics were calculated. Results A descriptive and detailed grading system with corresponding FS PD and T2 mapping images has been presented. Inter-rater agreement was 0.80 (95% confidence interval [CI], 0.71-0.89). Intra-rater agreements were 0.83 (95% CI, 0.74-0.91) for observer A and 0.79 (95% CI, 0.70-0.88) for observer B (k-values). Conclusion We present a new MRI grading system for chondromalacia patellae with corresponding images and good inter- and intra-rater agreement which might be useful in reporting and comparing knee MRI examinations in daily practice and may also have the potential for using more precisely predicting prognosis and clinical outcome of the patients.

Cartilage repair in the degenerative ageing knee

Background and purpose - Cartilage damage can develop due to trauma, resulting in focal chondral or osteochondral defects, or as more diffuse loss of cartilage in a generalized organ disease such as osteoarthritis. A loss of cartilage function and quality is also seen with increasing age. There is a spectrum of diseases ranging from focal cartilage defects with healthy surrounding cartilage to focal lesions in degenerative cartilage, to multiple and diffuse lesions in osteoarthritic cartilage. At the recent Aarhus Regenerative Orthopaedics Symposium (AROS) 2015, regenerative challenges in an ageing population were discussed by clinicians and basic scientists. A group of clinicians was given the task of discussing the role of tissue engineering in the treatment of degenerative cartilage lesions in ageing patients. We present the outcomes of our discussions on current treatment options for such lesions, with particular emphasis on different biological repair techniques and their supporting level of evidence. Results and interpretation - Based on the studies on treatment of degenerative lesions and early OA, there is low-level evidence to suggest that cartilage repair is a possible treatment for such lesions, but there are conflicting results regarding the effect of advanced age on the outcome. We concluded that further improvements are needed for direct repair of focal, purely traumatic defects before we can routinely use such repair techniques for the more challenging degenerative lesions. Furthermore, we need to identify trigger mechanisms that start generalized loss of cartilage matrix, and induce subchondral bone changes and concomitant synovial pathology, to maximize our treatment methods for biological repair in degenerative ageing joints.

Deciding How Best to Treat Cartilage Defects

The decision-making regarding and treatment of cartilage abnormalities requires a systematic approach. This article reviews the concepts and principles that guide the management of this complex problem. The precise incidence, demographics, and progression of cartilage lesions have not been clearly delineated. Pursuing a patient-centered approach that considers the available nonsurgical and surgical options remains the cornerstone of patient care. The importance of determining concomitant knee pathologies, the proper interpretation and implications of imaging findings, and an accurate determination of the intra-articular and subchondral findings represent the primary elements of the decision analysis. Treatment options vary depending on patient goals, the disposition of the lesion, and a variety of other factors. The authors recommend proper patient education and consideration of how nonsurgical treatment or less invasive options such as arthroscopic debridement might be effective. If these strategies should fail, appropriate matching of a surgical procedure to the patient's pathology, goals, and expectations is warranted. Surgical options include debridement, marrow stimulation techniques, surface allograft treatments, autologous chondrocyte implantation, and osteochondral grafting (autograft and allograft) in addition to some emerging technologies. This article focuses on the decision-making process. [Orthopedics. 2016; 39(6):343-350.].

Early evolving joint degeneration by cartilage trauma is primarily mechanically controlled

BACKGROUND

Mechanical and inflammatory processes add to osteoarthritis (OA). To what extent both processes contribute during the onset of OA after a cartilage trauma is unknown. This study evaluates whether local cartilage damage leads to focally confined or more generalized cartilage damage with synovial inflammation in the early development of joint tissue degeneration.

METHODS

In nine goats, cartilage damage was surgically induced on the weight bearing area of exclusively the medial femoral condyle of the right knee joint. The other tibio-femoral compartments, lateral femoral condyle and lateral medial tibial plateau, were left untouched. The contralateral left knee joint of each animal served as an intra-animal control. Twenty weeks post-surgery changes in cartilage matrix integrity in each of the four compartments, medial and lateral synovial tissue inflammation, and synovial fluid IL-1β and TNFα were evaluated.

RESULTS

In the experimental medial femoral plateau, significant macroscopic, histologic, and biochemical cartilage damage was observed versus the contralateral control compartments. Also the articulating cartilage of the experimental medial tibial plateau was significantly more damaged. Whereas, no differences were seen between the lateral compartments of experimental and contralateral control joints. Synovial tissue inflammation was mild and only macroscopically (not histologically) significantly increased in the experimental medial compartments. Synovial fluid IL-1β level was not different between experimental and contralateral control joints, and TNFα was overall beneath the detection limit.

CONCLUSIONS

Local cartilage damage is a trigger for development of OA, which in early onset seems primarily mechanically driven. Early treatment of traumatic cartilage damage should take this mechanical component into consideration.

Correlates of Hip Cartilage Defects: A Cross-sectional Study in Older Adults

OBJECTIVE

Knee cartilage defects are a key feature of osteoarthritis (OA) but correlates of hip defects remain unexplored. The aims of this cross-sectional study were to describe the correlates of hip cartilage defects.

METHODS

The study included 194 subjects from the Tasmanian Older Adult Cohort who had right hip short-tau inversion recovery magnetic resonance imaging (MRI). Hip cartilage defects were assessed and categorized as grade 0 = no defects, grade 1 = focal blistering or irregularities on cartilage or partial thickness defect, and grade 2 = full thickness defect. Hip pain was determined by Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). Hip structural changes were measured on MRI, and hip radiographic OA (ROA) was assessed. Leg strength and physical activity were assessed using dynamometer and pedometers, respectively. Data were analyzed using log binomial and linear regression.

RESULTS

Of 194 subjects, 24% (n = 48) had no defects, 34% (n = 66) had grade 1, and 41% (n = 80) had grade 2. In multivariable analyses, any hip defects were associated with greater hip pain [prevalence ratio (PR) 1.20, 95% CI 1.02-1.35] and lower mean leg strength (men; mean ratio 0.83, 95% CI 0.67-0.98). Grade 1 defects were associated with hip bone marrow lesions (BML; PR 1.42, 95% CI 1.03-1.96) and high cartilage signal (men; PR 1.84, 95% CI 1.27-2.70), but not with hip pain or other structural findings. Grade 2 defects were associated with greater hip pain (PR 1.40, 95% CI 1.09-1.80), hip BML (PR 1.45, 95% CI 1.15-1.85), hip effusion cross-sectional area (PR 1.14, 95% CI 1.01-1.30), hip ROA (men; PR 1.60, 95% CI 1.13-2.25), and steps/day (PR 0.97, 95% CI 0.96-0.99).

CONCLUSION

Grade 2 defects in both sexes and grade 1 defects (mostly in men) are associated with clinical, demographic, and structural factors relevant for OA. Damage to the hip cartilage could be one of the major causes of rapid disease progression and pathophysiology of hip defects. The topic needs further study.

The relationship between three-dimensional knee MRI bone shape and total knee replacement-a case control study: data from the Osteoarthritis Initiative

Objective. There is growing understanding of the importance of bone in OA. Our aim was to determine the relationship between 3D MRI bone shape and total knee replacement (TKR).

Methods. A nested case-control study within the Osteoarthritis Initiative cohort identified case knees with confirmed TKR for OA and controls that were matched using propensity scores. Active appearance modelling quantification of the bone shape of all knee bones identified vectors between knees having or not having OA. Vectors were scaled such that −1 and +1 represented the mean non-OA and mean OA shapes.

Results. Compared to controls (n = 310), TKR cases (n = 310) had a more positive mean baseline 3D bone shape vector, indicating more advanced structural OA, for the femur [mean 0.98 vs −0.11; difference (95% CI) 1.10 (0.88, 1.31)], tibia [mean 0.86 vs −0.07; difference (95% CI) 0.94 (0.72, 1.16)] and patella [mean 0.95 vs 0.03; difference (95% CI) 0.92 (0.65, 1.20)]. Odds ratios (95% CI) for TKR per normalized unit of 3D bone shape vector for the femur, tibia and patella were: 1.85 (1.59, 2.16), 1.64 (1.42, 1.89) and 1.36 (1.22, 1.50), respectively, all P < 0.001. After including Kellgren–Lawrence grade in a multivariable analysis, only the femur 3D shape vector remained significantly associated with TKR [odds ratio 1.24 (1.02, 1.51)].

Conclusion. 3D bone shape was associated with the endpoint of this study, TKR, with femoral shape being most associated. This study contributes to the validation of quantitative MRI bone biomarkers for OA structure-modification trials.

Can Signal Abnormalities Detected with MR Imaging in Knee Articular Cartilage Be Used to Predict Development of Morphologic Cartilage Defects? 48-Month Data from the Osteoarthritis Initiative

Purpose To determine the incidence with which morphologic articular cartilage defects develop over 48 months in cartilage with signal abnormalities at baseline magnetic resonance (MR) imaging in comparison with the incidence in articular cartilage without signal abnormalities at baseline. Materials and Methods The institutional review boards of all participating centers approved this HIPAA-compliant study. Right knees of 90 subjects from the Osteoarthritis Initiative (mean age, 55 years ± 8 [standard deviation]; 51% women) with cartilage signal abnormalities but without morphologic cartilage defects at 3.0-T MR imaging and without radiographic osteoarthritis (Kellgren-Lawrence score, 0-1) were frequency matched for age, sex, Kellgren-Lawrence score, and body mass index with right knees in 90 subjects without any signal abnormalities or morphologic defects in the articular cartilage (mean age, 54 years ± 5; 51% women). Individual signal abnormalities (n = 126) on intermediate-weighted fast spin-echo MR images were categorized into four subgrades: subgrade A, hypointense; subgrade B, inhomogeneous; subgrade C, hyperintense; and subgrade D, hyperintense with swelling. The development of morphologic articular cartilage defects (Whole-Organ MR Imaging Score ≥2) at 48 months was analyzed on a compartment level and was compared between groups by using generalized estimating equation logistic regression models. Results Cartilage signal abnormalities were more frequent in the patellofemoral joint than in the tibiofemoral joint (59.5% vs 39.5%). Subgrade A was seen more frequently than were subgrades C and D (36% vs 22%). Incidence of morphologic cartilage defects at 48 months was 57% in cartilage with baseline signal abnormalities, while only 4% of compartments without baseline signal abnormalities developed morphologic defects at 48 months (all compartments combined and each compartment separately, P < .01). The development of morphologic defects was not significantly more likely in any of the subgrades (P = .98) and was significantly associated with progression of bone marrow abnormalities (P = .002). Conclusion Knee cartilage signal abnormalities detected with MR imaging are precursors of morphologic defects with osteoarthritis and may serve as imaging biomarkers with which to assess risk for cartilage degeneration. (©) RSNA, 2016.

Do Moments and Strength Predict Cartilage Changes after Partial Meniscectomy?

PURPOSE

Higher knee load and quadriceps weakness are potential factors involved in the pathogenesis of knee osteoarthritis after arthroscopic partial meniscectomy (APM). In people following APM, this study evaluated the association between external knee joint moments and quadriceps strength and 2-yr change in indices of cartilage integrity in the medial tibiofemoral compartment and patella.

METHODS

Seventy people with medial APM were assessed 3 months after APM (baseline) and reassessed 2 yr later (follow-up). At baseline, isokinetic quadriceps strength and the external knee adduction moment (peak and impulse) and knee flexion moment (peak) during walking were assessed. Magnetic resonance imaging was used to assess cartilage (cartilage volume and cartilage defects) in the medial tibial compartment and patella at baseline and follow-up.

RESULTS

Increased peak knee adduction moment during fast-pace walking at baseline was associated with onset or deterioration of medial tibiofemoral cartilage defects (OR, 2.06; 95% CI, 1.03-4.12; P = 0.042) over 2 yr. Increased peak knee flexion moment during normal-pace walking at baseline was associated with loss of patellar cartilage volume over 2 yr (β = -0.24; 95% CI, -0.47 to -0.01; P = 0.04). No significant association was observed for quadriceps strength.

CONCLUSION

In middle-age adults, a higher peak knee adduction moment and peak knee flexion moment at 3 months after medial APM may be associated with adverse structural changes at the medial tibia and patella over the subsequent 2 yr. These preliminary findings warrant further investigation as interventions aimed at reducing these moments may be designed if appropriate.

Baseline radiographic osteoarthritis and semi-quantitatively assessed meniscal damage and extrusion and cartilage damage on MRI is related to quantitatively defined cartilage thickness loss in knee osteoarthritis: the Multicenter Osteoarthritis Study

OBJECTIVES

To provide a comprehensive simultaneous relation of various semiquantitative knee OA MRI features as well as the presence of baseline radiographic osteoarthritis (OA) to quantitative longitudinal cartilage loss.

METHODS

We studied Multicenter OA Study (MOST) participants from a longitudinal observational study that included quantitative MRI measurement of cartilage thickness. These subjects also had Whole Organ MRI Score (WORMS) scoring of cartilage damage, bone marrow lesions (BMLs), meniscal pathology, and synovitis, as well as baseline radiographic evaluation for Kellgren and Lawrence (KL) grading. Knee compartments were classified as progressors when exceeding thresholds of measurement variability in normal knees. All potential risk factors of cartilage loss were dichotomized into "present" (score ≥2 for cartilage, ≥1 for others) or "absent". Differences in baseline scores of ipsi-compartmental risk factors were compared between progressor and non-progressor knees by multivariable logistic regression, adjusting for age, sex, body mass index, alignment axis (degrees) and baseline KL grade. Odds ratios (OR) and 95% CIs were calculated for medial femorotibial compartment (MFTC) and lateral femorotibial compartment (LFTC) cartilage loss. Cartilage loss across both compartments was studied using Generalized Estimating Equations.

RESULTS

196 knees of 196 participants were included (age 59.8 ± 6.3 years [mean ± SD], BMI 29.5 ± 4.6, 62% women). For combined analyses of MFTC and LFTC, baseline factors related to cartilage loss were radiographic OA (KL grade ≥2: aOR 4.8 [2.4-9.5], cartilage damage (aOR 2.3 [1.2-4.4])), meniscal damage (aOR 3.9 [2.1-7.4]) and extrusion (aOR 2.9 [1.6-5.3]), all in the ipsilateral compartment, but not BMLs or synovitis.

CONCLUSION

Baseline radiographic OA and semiquantitatively (SQ) assessed MRI-detected cartilage damage, meniscal damage and extrusion, but not BMLs or synovitis is related to quantitatively measured ipsi-compartmental cartilage thinning over 30 months.

Higher Knee Flexion Moment During the Second Half of the Stance Phase of Gait Is Associated With the Progression of Osteoarthritis of the Patellofemoral Joint on Magnetic Resonance Imaging

STUDY DESIGN

Controlled laboratory study, longitudinal design.

OBJECTIVE

To examine whether baseline knee flexion moment or impulse during walking is associated with the progression of osteoarthritis (OA) with magnetic resonance imaging of the patellofemoral joint (PFJ) at 1 year.

BACKGROUND

Patellofemoral joint OA is highly prevalent and a major source of pain and dysfunction. The biomechanical factors associated with the progression of PFJ OA remain unclear.

METHODS

Three-dimensional gait analyses were performed at baseline. Magnetic resonance imaging of the knee (high-resolution, 3-D, fast spin-echo sequence) was used to identify PFJ cartilage and bone marrow edema-like lesions at baseline and a 1-year follow-up. The severity of PFJ OA progression was defined using the modified Whole-Organ Magnetic Resonance Imaging Score when new or increased cartilage or bone marrow edema-like lesions were observed at 1 year. Peak external knee flexion moment and flexion moment impulse during the first and second halves of the stance phase of gait were compared between progressors and nonprogressors, and used to predict progression after adjusting for age, sex, body mass index, and presence of baseline PFJ OA.

RESULTS

Sixty-one participants with no knee OA or isolated PFJ OA were included. Patellofemoral joint OA progressors (n = 10) demonstrated significantly higher peak knee flexion moment (P = .01) and flexion moment impulse (P = .04) during the second half of stance at baseline compared to nonprogressors. Logistic regression showed that higher peak knee flexion moment during the second half of the stance phase was significantly associated with progression at 1 year (adjusted odds ratio = 3.3, P = .01).

CONCLUSION

Peak knee flexion moment and flexion moment impulse during the second half of stance are related to the progression of PFJ OA and may need to be considered when treating individuals who are at risk of or who have PFJ OA.

Wolff's law in action: a mechanism for early knee osteoarthritis

There is growing interest in the role of bone in knee osteoarthritis. Bone is a dynamic organ, tightly regulated by a multitude of homeostatic controls, including genetic and environmental factors. One such key environmental regulator of periarticular bone is mechanical stimulation, which, according to Wolff’s law, is a key determinant of bone properties. Wolff’s law theorizes that repetitive loading of bone will cause adaptive responses enabling the bone to better cope with these loads. Despite being an adaptive response of bone, the remodeling process may inadvertently trigger maladaptive responses in other articular structures. Accumulating evidence at the knee suggests that expanding articular bone surface area is driven by mechanical stimulation and is a strong predictor of articular cartilage loss. Similarly, fractal analysis of bone architecture provides further clues that bone adaptation may have untoward consequences for joint health. This review hypothesizes that adaptations of periarticular bone in response to mechanical stimulation cause maladaptive responses in other articular structures that mediate the development of knee osteoarthritis. A potential disease paradigm to account for such a hypothesis is also proposed, and novel therapeutic targets that may have a bone-modifying effect, and therefore potentially a disease-modifying effect, are also explored.

A systematic review of the relationship between subchondral bone features, pain and structural pathology in peripheral joint osteoarthritis

INTRODUCTION

Bone is an integral part of the osteoarthritis (OA) process. We conducted a systematic literature review in order to understand the relationship between non-conventional radiographic imaging of subchondral bone, pain, structural pathology and joint replacement in peripheral joint OA.

METHODS

A search of the Medline, EMBASE and Cochrane library databases was performed for original articles reporting association between non-conventional radiographic imaging-assessed subchondral bone pathologies and joint replacement, pain or structural progression in knee, hip, hand, ankle and foot OA. Each association was qualitatively characterised by a synthesis of the data from each analysis based upon study design, adequacy of covariate adjustment and quality scoring.

RESULTS

In total 2456 abstracts were screened and 139 papers were included (70 cross-sectional, 71 longitudinal analyses; 116 knee, 15 hip, six hand, two ankle and involved 113 MRI, eight DXA, four CT, eight scintigraphic and eight 2D shape analyses). BMLs, osteophytes and bone shape were independently associated with structural progression or joint replacement. BMLs and bone shape were independently associated with longitudinal change in pain and incident frequent knee pain respectively.

CONCLUSION

Subchondral bone features have independent associations with structural progression, pain and joint replacement in peripheral OA in the hip and hand but especially in the knee. For peripheral OA sites other than the knee, there are fewer associations and independent associations of bone pathologies with these important OA outcomes which may reflect fewer studies; for example the foot and ankle were poorly studied. Subchondral OA bone appears to be a relevant therapeutic target.

SYSTEMATIC REVIEW

PROSPERO registration number: CRD 42013005009.

Early cartilage abnormalities at the hip are associated with obesity and body composition measures - a 3.0T MRI community-based study

Introduction

Although obesity is a risk factor for hip osteoarthritis (OA), the role of body composition, if any, is unclear. This study examines whether the body mass index (BMI) and body composition are associated with hip cartilage changes using magnetic resonance imaging (MRI) in community-based adults.

Methods

141 community-based participants with no clinical hip disease, including OA, had BMI and body composition (fat mass and fat free mass) measured at baseline (1990 to 1994), and BMI measured and 3.0 T MRI performed at follow-up (2009–2010). Femoral head cartilage volume was measured and femoral head cartilage defects were scored in the different hip regions.

Results

For females, baseline BMI (β = −26 mm³, 95% Confidence interval (CI) -47 to −6 mm³, p = 0.01) and fat mass (β = −11 mm³, 95% CI −21 to −1 mm³, p = 0.03) were negatively associated with femoral head cartilage volume. Also, while increased baseline fat mass was associated with an increased risk of cartilage defects in the central superolateral region of the femoral head (Odds Ratio (OR) = 1.08, 95% CI 1.00–1.15, p = 0.04), increased baseline fat free mass was associated with a reduced risk of cartilage defects in this region (OR = 0.82, 95% CI 0.67–0.99; p = 0.04). For males, baseline fat free mass was associated with increased femoral head cartilage volume (β = 40 mm³, 95% CI 6 to 74 mm³, p = 0.02).

Conclusions

Increased fat mass was associated with adverse hip cartilage changes for females, while increased fat free mass was associated with beneficial cartilage changes for both genders. Further work is required to determine whether modifying body composition alters the development of hip OA.

Structural changes of hip osteoarthritis using magnetic resonance imaging

INTRODUCTION

Few data are available concerning structural changes at the hip observed by magnetic resonance imaging (MRI) in people with or without hip osteoarthritis (OA). The aim of this study was to compare cartilage volume and the presence of cartilage defects and bone marrow lesions (BMLs) in participants with and without diagnosed hip OA.

METHODS

Femoral head cartilage volume was measured by MRI for 141 community-based persons with no diagnosed hip OA, and 19 with diagnosed hip OA. Cartilage defects and BMLs were regionally scored at the femoral head and acetabulum.

RESULTS

Compared with those without diagnosed hip OA, people with diagnosed hip OA had less femoral head cartilage volume (1763 mm3 versus 3343 mm3; p < 0.001) and more prevalent cartilage defects and BMLs (all p ≤ 0.05) at all sites other than the central inferomedial region of the femoral head. In those with no diagnosed hip OA, cartilage defects in the anterior and central superolateral region of the femoral head were associated with reduced femoral head cartilage volume (all p ≤ 0.02). Central superolateral BMLs at all sites were associated with reduced femoral head cartilage volume (all p ≤ 0.003), with a similar trend occurring when BMLs were located in the anterior region of the hip (all p ≤ 0.08).

CONCLUSIONS

Compared with community-based adults with no diagnosed hip OA, people with diagnosed hip OA have less femoral head cartilage volume and a higher prevalence of cartilage defects and BMLs. For people with no diagnosed hip OA, femoral head cartilage volume was reduced where cartilage defects and/or BMLs were present in the anterior and central superolateral regions of the hip joint. Cartilage defects and BMLs present in the anterior and central superolateral regions may represent early structural damage in the pathogenesis of hip OA.

Significance of preradiographic magnetic resonance imaging lesions in persons at increased risk of knee osteoarthritis

OBJECTIVE

Little is known about early knee osteoarthritis (OA). The significance of lesions on magnetic resonance imaging (MRI) in older persons without radiographic OA is unclear. Our objectives were to determine the extent of tissue pathology by MRI and evaluate its significance by testing the following hypotheses: cartilage damage, bone marrow lesions, and meniscal damage are associated with prevalent frequent knee symptoms and incident persistent symptoms; bone marrow lesions and meniscal damage are associated with incident tibiofemoral (TF) cartilage damage; and bone marrow lesions are associated with incident patellofemoral (PF) cartilage damage.

METHODS

In a cohort study of 849 Osteoarthritis Initiative (OAI) participants who had a bilateral Kellgren/Lawrence (K/L) score of 0, we assessed cartilage damage, bone marrow lesions, and meniscal damage using the MRI OA Knee Score, as well as prevalent frequent knee symptoms, incident persistent symptoms, and incident cartilage damage. Multiple logistic regression (one knee per person) was used to evaluate associations between MRI lesions and each of these outcomes.

RESULTS

Of the participants evaluated, 76% had cartilage damage, 61% had bone marrow lesions, 21% had meniscal tears, and 14% had meniscal extrusion. Cartilage damage (any; TF and PF), bone marrow lesions (any; TF and PF), meniscal extrusion, and body mass index (BMI) were associated with prevalent frequent symptoms. Cartilage damage (isolated PF; TF and PF), bone marrow lesions (any; isolated PF; TF and PF), meniscal tears, and BMI were associated with incident persistent symptoms. Hand OA, but no individual lesion type, was associated with incident TF cartilage damage, and bone marrow lesions (any; any PF) with incident PF damage. Having more lesion types was associated with a greater risk of outcomes.

CONCLUSION

MRI-detected lesions are not incidental and may represent early disease in persons at increased risk of knee OA.

History of knee injury and MRI-assessed knee structures in middle- and older-aged adults: a cross-sectional study

The aim of this cross-sectional study was to describe the associations between history of knee injury and knee structure using magnetic resonance imaging (MRI). This study included two population-based samples: the Tasmanian Older Adult Cohort (TASOAC) study (n = 430; mean age, 63.0 years; range, 51-79 years; 51 % female) and the Offspring study (n = 372; mean age, 45.0 years; range, 26-61 years; 57.5 % female). In both studies, 1.5 T MRI scans of the right knee were performed to measure bone marrow lesions (BMLs), cartilage volume, tibial bone area, cartilage defects and meniscal pathology. History of knee injury was assessed using a self-administered questionnaire. The association between knee injury and knee structure was determined using multiple linear and log binomial regression models. Nineteen percent of the middle-aged and 12 % of the older adults reported a history of knee injury. In middle-aged adults, BML presence (prevalence ratio (PR) = 1.6 (95 % CI, 1.2; 2.1)), tibial bone area (difference of means (DM) = +86 (+23, +149)) and meniscal extrusion presence (PR = 2.7 (1.1, 6.8)) were significantly higher in those with knee injury. In older adults, cartilage defect presence (PR = 1.3 (1.0, 1.7)), lateral (DM = -265 (-439, -92)) and total tibial (DM = -325 (-600, -51)) cartilage volume, BML presence (PR = 1.4 (1.0, 1.9)) and tibial bone area (DM = +140 (+19, +260)) were significantly associated with knee injury. Meniscal tears showed no significant associations in either cohorts. The association between knee injury and MRI-assessed structural pathology in the knee joint is moderate and appears to be stronger in older adults compared to middle-aged adults.

Clinical and translational potential of MRI evaluation in knee osteoarthritis

Magnetic resonance imaging (MRI) has become an increasingly important imaging technique in osteoarthritis (OA) research, and is widely used in the ongoing endeavor to understand the pathogenesis of OA and to develop structure and disease-modifying OA drugs. MRI offers semiquantitative, quantitative and compositional evaluation of knee OA, and enables visualization of tissues that are not seen by radiography, including but not limited to cartilage, meniscus, bone marrow lesions, synovitis, and muscles. It is now recognized that contrast-enhanced MRI enables more accurate evaluation of synovitis than MRI without contrast. Because of its ability to visualize multiple pain-related tissue pathology in three dimensions, MRI is the best modality for imaging of OA.

Concise review: unraveling stem cell cocultures in regenerative medicine: which cell interactions steer cartilage regeneration and how?

Cartilage damage and osteoarthritis (OA) impose an important burden on society, leaving both young, active patients and older patients disabled and affecting quality of life. In particular, cartilage injury not only imparts acute loss of function but also predisposes to OA. The increase in knowledge of the consequences of these diseases and the exponential growth in research of regenerative medicine have given rise to different treatment types. Of these, cell-based treatments are increasingly applied because they have the potential to regenerate cartilage, treat symptoms, and ultimately prevent or delay OA. Although these approaches give promising results, they require a costly in vitro cell culture procedure. The answer may lie in single-stage procedures that, by using cell combinations, render in vitro expansion redundant. In the last two decades, cocultures of cartilage cells and a variety of (mesenchymal) stem cells have shown promising results as different studies report cartilage regeneration in vitro and in vivo. However, there is considerable debate regarding the mechanisms and cellular interactions that lead to chondrogenesis in these models. This review, which included 52 papers, provides a systematic overview of the data presented in the literature and tries to elucidate the mechanisms that lead to chondrogenesis in stem cell cocultures with cartilage cells. It could serve as a basis for research groups and clinicians aiming at designing and implementing combined cellular technologies for single-stage cartilage repair and treatment or prevention of OA.

Concise review: unraveling stem cell cocultures in regenerative medicine: which cell interactions steer cartilage regeneration and how?

Cartilage damage and osteoarthritis (OA) impose an important burden on society, leaving both young, active patients and older patients disabled and affecting quality of life. In particular, cartilage injury not only imparts acute loss of function but also predisposes to OA. The increase in knowledge of the consequences of these diseases and the exponential growth in research of regenerative medicine have given rise to different treatment types. Of these, cell-based treatments are increasingly applied because they have the potential to regenerate cartilage, treat symptoms, and ultimately prevent or delay OA. Although these approaches give promising results, they require a costly in vitro cell culture procedure. The answer may lie in single-stage procedures that, by using cell combinations, render in vitro expansion redundant. In the last two decades, cocultures of cartilage cells and a variety of (mesenchymal) stem cells have shown promising results as different studies report cartilage regeneration in vitro and in vivo. However, there is considerable debate regarding the mechanisms and cellular interactions that lead to chondrogenesis in these models. This review, which included 52 papers, provides a systematic overview of the data presented in the literature and tries to elucidate the mechanisms that lead to chondrogenesis in stem cell cocultures with cartilage cells. It could serve as a basis for research groups and clinicians aiming at designing and implementing combined cellular technologies for single-stage cartilage repair and treatment or prevention of OA.

Popliteal cysts and subgastrocnemius bursitis are associated with knee symptoms and structural abnormalities in older adults: a cross-sectional study

Introduction

The role of popliteal cysts and subgastrocnemius bursitis in knee joint homeostasis is uncertain. The aim of this study is to describe cross-sectional associations between popliteal cysts, subgastrocnemius bursitis, knee symptoms and structural abnormalities in older adults.

Methods

A cross-sectional sample of 900 randomly-selected subjects (mean age 63 years, 48% female) were studied. Knee pain, stiffness and dysfunction were assessed by self-administered Western Ontario McMaster Osteoarthritis Index (WOMAC) questionnaire. Radiographic knee osteophyte and joint space narrowing (JSN) were recorded. Magnetic resonance imaging (MRI) was utilized to assess popliteal cysts, subgastrocnemius bursitis, cartilage defects and bone marrow lesions (BMLs).

Results

Popliteal cysts were present in 11.7% and subgastrocnemius bursitis in 12.7% of subjects. Subgastrocnemius bursitis was more common in those with popliteal cyst (36.2% versus 9.7%, P <0.01). In multivariable analyses, popliteal cysts were significantly associated with increased osteophytes in both medial and lateral tibiofemoral compartments while subgastrocnemius bursitis was associated with increased osteophytes and JSN in the medial tibiofemoral compartment. Both were significantly associated with cartilage defects in all compartments, and with BMLs in the medial tibiofemoral compartment. Furthermore, both popliteal cysts and subgastrocnemius bursitis were significantly associated with increased weight-bearing knee pain but these associations became non-significant after adjustment for cartilage defects and BMLs.

Conclusions

Popliteal cysts and subgastrocnemius bursitis are associated with increased symptoms as well as radiographic and MRI-detected joint structural abnormalities. Longitudinal data will help resolve if they are a consequence or a cause of knee joint abnormalities.

Osteoarthritis year 2013 in review: imaging

PURPOSE

To review recent original research publications related to imaging of osteoarthritis (OA) and identify emerging trends and significant advances.

METHODS

Relevant articles were identified through a search of the PubMed database using the query terms "OA" in combination with "imaging", "radiography", "MRI", "ultrasound", "computed tomography", and "nuclear medicine"; either published or in press between March 2012 and March 2013. Abstracts were reviewed to exclude review articles, case reports, and studies not focused on imaging using routine clinical imaging measures.

RESULTS

Initial query yielded 932 references, which were reduced to 328 citations following the initial review. MRI (118 references) and radiography (129 refs) remain the primary imaging modalities in OA studies, with fewer reports using computed tomography (CT) (35 refs) and ultrasound (23 refs). MRI parametric mapping techniques remain an active research area (33 refs) with growth in T2*- and T1-rho mapping publications compared to prior years. Although the knee is the major joint studied (210 refs) there is interest in the hip (106 refs) and hand (29 refs). Imaging continues to focus on evaluation of cartilage (173 refs) and bone (119 refs).

CONCLUSION

Imaging plays a major role in OA research with publications continuing along traditional lines of investigation. Translational and clinical research application of compositional MRI techniques is becoming more common driven in part by the availability of T2 mapping data from the Osteoarthritis Initiative (OAI). New imaging techniques continue to be developed with a goal of identifying methods with greater specificity and responsiveness to changes in the joint, and novel functional neuroimaging techniques to study central pain. Publications related to imaging of OA continue to be heavily focused on quantitative and semiquantitative MRI evaluation of the knee with increasing application of compositional MRI techniques in the hip.