Subclinical cartilage degeneration in young athletes with posterior cruciate ligament injuries detected with T1ρ magnetic resonance imaging mapping

Epidemiology and distribution of cruciate ligament injuries in children and adolescents, with an analysis of risk factors for concomitant meniscal tear

Introduction

To investigate the epidemiological features and prevalence of cruciate ligament injuries (CLI) in children and adolescents, and to examine the potential risk factors associated with concomitant meniscal tear (MT) among this population.

Methods

The demographic data and injury details of children and adolescents with CLI from Southeast China were analyzed to describe their distribution characteristics, alongside an analysis of the prevalence of MTs, the most frequent complication. In addition, binary logistic analysis was employed to ascertain the risk factors linked to MT in individuals suffering from CLI.

Results

A total of 203 patients with CLI (n = 206) met the inclusion criteria, with a male-to-female ratio of 2.3:1. Notably, a higher proportion of females were aged ≤16 years old compared to males, who predominated in patients aged >16 years (P = 0.001). Among children and adolescents, anterior cruciate ligament (ACL) injuries were the primary type of CLI, accounting for 88.18% (179/203) of all cases. The majority of cases (132/203, 65.02%) were sustained during sports activities, and sprains were the predominant mechanism of injury (176/203, 86.7%). Additionally, the most common associated injury was an MT (157/203, 77.34%). The posterior horn is the most frequently affected site for both medial MT (62.93% out of 73 cases) and lateral MT (70.19% out of 73 cases). Moreover, vertical tears constituted the majority of medial MTs (59.48% out of 116 cases). Furthermore, patients with a higher BMI faced an increased risk of associated MT in comparison to non-overweight patients (88% vs. 73.86%; P = 0.038). Each increase in BMI unit was linked with a 14% higher probability of associated MT occurrence in children and adolescents with CLI (OR = 1.140; P = 0.036).

Discussion

ACL injuries are a common form of knee ligament injury among children and adolescents, especially those over the age of 16, and are often the result of a sprain. Meniscal posterior horn injury is the most commonly associated injury of youth with CLI. Additionally, overweight or obese people with CLI are at a greater risk of developing MT.

Multiparametric MRI of Knees in Collegiate Basketball Players: Associations With Morphological Abnormalities and Functional Deficits

Background

Rates of cartilage degeneration in asymptomatic elite basketball players are significantly higher compared with the general population due to excessive loads on the knee. Compositional quantitative magnetic resonance imaging (qMRI) techniques can identify local biochemical changes of macromolecules observed in cartilage degeneration.

Purpose/Hypothesis

The purpose of this study was to utilize multiparametric qMRI to (1) quantify how T1ρ and T2 relaxation times differ based on the presence of anatomic abnormalities and (2) correlate T1ρ and T2 with self-reported functional deficits. It was hypothesized that prolonged relaxation times will be associated with knees with MRI-graded abnormalities and knees belonging to basketball players with greater self-reported functional deficits.

Study Design

Cross-sectional study; Level of evidence, 3.

Methods

A total of 75 knees from National Collegiate Athletic Association Division I basketball players (40 female, 35 male) were included in this multicenter study. All players completed the Knee injury and Osteoarthritis Outcome Score (KOOS) and had bilateral knee MRI scans taken. T1ρ and T2 were calculated on a voxel-by-voxel basis. The cartilage surfaces were segmented into 6 compartments: lateral femoral condyle, lateral tibia, medial femoral condyle, medial tibia (MT), patella (PAT), and trochlea (TRO). Lesions from the MRI scans were graded for imaging abnormalities, and statistical parametric mapping was performed to study cross-sectional differences based on MRI scan grading of anatomic knee abnormalities. Pearson partial correlations between relaxation times and KOOS subscore values were computed, obtaining r value statistical parametric mappings and P value clusters.

Results

Knees without patellar tendinosis displayed significantly higher T1ρ in the PAT compared with those with patellar tendinosis (average percentage difference, 10.4%; P = .02). Significant prolongation of T1ρ was observed in the MT, TRO, and PAT of knees without compared with those with quadriceps tendinosis (average percentage difference, 12.7%, 13.3%, and 13.4%, respectively; P ≤ .05). A weak correlation was found between the KOOS-Symptoms subscale values and T1ρ/T2.

Conclusion

Certain tissues that bear the brunt of impact developed tendinosis but spared cartilage degeneration. Whereas participants reported minimal functional deficits, their high-impact activities resulted in structural damage that may lead to osteoarthritis after their collegiate careers.

Walking with a Posterior Cruciate Ligament Injury: A Musculoskeletal Model Study

The understanding of the changes induced in the knee's kinematics by a Posterior Cruciate Ligament (PCL) injury is still rather incomplete. This computational study aimed to analyze how the internal loads are redistributed among the remaining ligaments when the PCL is lesioned at different degrees and to understand if there is a possibility to compensate for a PCL lesion by changing the hamstring's contraction in the second half of the swing phase. A musculoskeletal model of the knee joint was used for simulating a progressive PCL injury by gradually reducing the ligament stiffness. Then, in the model with a PCL residual stiffness at 15%, further dynamic simulations of walking were performed by progressively reducing the hamstring's force. In each condition, the ligaments tension, contact force and knee kinematics were analyzed. In the simulated PCL-injured knee, the Medial Collateral Ligament (MCL) became the main passive stabilizer of the tibial posterior translation, with synergistic recruitment of the Lateral Collateral Ligament. This resulted in an enhancement of the tibial-femoral contact force with respect to the intact knee. The reduction in the hamstring's force limited the tibial posterior sliding and, consequently, the tension of the ligaments compensating for PCL injury decreased, as did the tibiofemoral contact force. This study does not pretend to represent any specific population, since our musculoskeletal model represents a single subject. However, the implemented model could allow the non-invasive estimation of load redistribution in cases of PCL injury. Understanding the changes in the knee joint biomechanics could help clinicians to restore patients' joint stability and prevent joint degeneration.

Standardized Rehabilitation or Individual Approach?—A Retrospective Analysis of Early Rehabilitation Protocols after Isolated Posterior Cruciate Ligament Reconstruction

(1) Background: Isolated posterior cruciate ligament (PCL) tears represent a severe type of injury. In hospitals, PCL reconstruction (PCL-R) is less frequently performed than other types of knee surgery. It is unclear whether there is consensus among surgeons on how to perform rehabilitation after PCL-R or if there are different, more individual approaches in daily routines. (2) Methods: Rehabilitation protocols and their main criteria (the progression of weight bearing and range of motion, the use of knee braces, rehabilitation training, and sports-specific training) were retrospectively analyzed after PCL-R. (3) Results: Only 33 of 120 (27.5%) analyzed institutes use rehabilitation protocols after PCL-R. The applied protocols showed vast differences between the individual rehabilitation criteria, especially with regard to the progression of weight bearing and the range of motion. The only standardized recommendations were the obligatory use of knee braces and the general restriction of weight bearing and range of motion immediately post-surgery. Therefore, because of the lack of a consensus about a standardized rehabilitation protocol after PCL-R, no recommendation can be made on one particular protocol. (4) Conclusion: There is no acknowledged standardized rehabilitation protocol after PCL-R. In clinical practice, recommendations are influenced by, i.a., surgeons’ opinions and experience. The lack of scientific evidence on a particular standardized rehabilitation protocol after PCL-R suggests that rehabilitation protocols need to be tailored to the individual patient.

Postsurgical status of articular cartilage after arthroscopic posterior cruciate ligament reconstruction in patients with or without concomitant meniscal pathology

PURPOSE

Several factors present at the time of posterior cruciate ligament reconstruction (PCLR) may cause the subsequent progression of articular cartilage lesions. This study aimed to evaluate postsurgical articular cartilage lesions which can be seen on MRI in patients who underwent arthroscopic PCLR with or without concomitant meniscal pathology.

MATERIAL AND METHODS

A total of sixty-five patients (mean age 35.8 ± 12.3 years) who underwent arthroscopic PCLR were included in this retrospective study. Patients were divided into two groups: ten patients with concomitant meniscal injuries at the time of PCLR who underwent meniscal surgery and fifty-five patients with intact menisci. The cartilage status of all knees was evaluated by MRI and modified Noyes classification.

RESULTS

Cartilage lesions were observed in 18 patients (27.7%) on the last follow-up MRI. The cartilage lesions were more common in the medial (15.4%) and patellofemoral (12.3%) compartments than in the lateral compartment (7.7%). Progression of cartilage lesions was present in 11 patients (16.9%) during follow-up MRI. The majority of cartilage lesions with progression were located in the medial compartment. The meniscal pathology group showed a higher prevalence of articular cartilage lesions on the last follow-up MRI (21.8% versus 60%, p = 0.022). In multivariate Cox regression, concomitant meniscal pathology was significantly associated with progression of articular cartilage lesions (p = 0.044).

CONCLUSION

PCLR patients with associated meniscal pathology showed worse cartilage condition and more progression of cartilage lesions than isolated PCLR patients. Attention to this risk factor might provide more applicable treatment options for potential osteoarthritis prevention strategies.

Injury to the Medial Superior Genicular Artery After Isolated Posterior Cruciate Ligament Reconstruction: A Case Report

CASE

A 19-year-old male patient with isolated posterior cruciate ligament (PCL) rupture underwent arthroscopic reconstruction using reinforced synthetic ligament (LARS system). Three weeks postoperatively, he presented with active bleeding from the medial side of his knee, near the proximal interference screw. An angiogram revealed extravasation from the medial superior genicular artery which was successfully embolized. One week later, he returned with active bleeding from the same area, located just under the initial coiling; a second embolization during superselective angiography was successful.

CONCLUSION

Although rare, minor vascular injuries are a risk inherent to PCL surgery.

Acceptable outcomes with unicompartmental knee replacement and PCL deficiency are achievable: a case series of nine patients

PURPOSE

Posterior cruciate ligament (PCL) deficiency is considered to be a contraindication for unicompartmental knee replacement (UKR); however, there is no evidence to support or contradict this. There are occasional circumstances where UKR in PCL deficient patients have been performed where the patient otherwise satisfies the indications for UKR. The aim of this paper is to describe the outcome of UKR in PCL deficient patients.

METHODS

A retrospective study of patients with painful medial compartment osteoarthritis and PCL deficiency treated with Oxford UKR between 2006 and 2015 was undertaken. Clinical records from a prospectively recorded database were reviewed and outcomes were assessed based on revision rate, Oxford Knee Score (OKS), American Knee Society score and Tegner Activity Score.

RESULTS

Nine patients were identified. The median age at surgery was 51 years (range 42-80) and median follow-up was 6 years (range 1-10). There was one bearing dislocation requiring open exchange. The outcome of seven patients was excellent (OKS > 41). Two patients, who were both elderly, had good outcomes (OKS 41 and 39). One patient had a poor outcome, but it is not clear if this was related to the knee as she had a learning disability and examination and radiographs of the knee were satisfactory.

CONCLUSION

The results of this small series suggest that excellent results can be achieved with UKR for selected patients with medial osteoarthritis in a PCL deficient knee that was functioning well before the osteoarthritis developed. On the basis of this a larger study should be undertaken. Until more results are available PCL deficiency should be considered a relative contra-indication to UKR.

LEVEL OF EVIDENCE

IV.

Clinical experience with arthroscopic suture pull technique in isolated PCL avulsion injuries

OBJECTIVE

to assess twenty two cases of isolated PCL avulsion fractures from tibial insertion, arthroscopically treated with suture pull technique, and to evaluate achieved clinical outcomes in terms of radiographic laxometry (objective) and Lysholm scale (subjective).

MATERIAL AND METHOD

Study includes 22 cases operated between April 2014 and March 2017. Patients less than 18 years old, presentation after 3 weeks of injury, concomitant injury in the same limb, with open wounds or with comminuted avulsed fragment were excluded from the study. All cases were MRI proven. All arthroscopic suture fixation technique was used in all cases. Follow up was done at 3 weeks, 6 weeks, 3 months, 6 months and 12 months. Mean follow up was one year. Subjective complaints, Knee flexion, Lysholm score and stress radiographs were noted.

RESULTS

Average Lysholm score was 96.3. Seventeen patients had excellent results and Five had good results based on Lysholm scores. In two patients, grade 2 laxity (5-10 mm) was present on stress radiographs but there were no clinical complaints. All patients achieved osseous union and had no functional limitation. Three Patients developed arthrofibrosis initially but gained functional range later.

CONCLUSION

Arthroscopic suture fixation method for PCL avulsion fracture from tibia is a good and safe method of choice for fixation.

MRI T2 and T1ρ relaxation in patients at risk for knee osteoarthritis: a systematic review and meta-analysis

Background

Magnetic resonance imaging (MRI) T2 and T1ρ relaxation are increasingly being proposed as imaging biomarkers potentially capable of detecting biochemical changes in articular cartilage before structural changes are evident. We aimed to: 1) summarize MRI methods of published studies investigating T2 and T1ρ relaxation time in participants at risk for but without radiographic knee OA; and 2) compare T2 and T1ρ relaxation between participants at-risk for knee OA and healthy controls.

Methods

We conducted a systematic review of studies reporting T2 and T1ρ relaxation data that included both participants at risk for knee OA and healthy controls. Participant characteristics, MRI methodology, and T1ρ and T2 relaxation data were extracted. Standardized mean differences (SMDs) were calculated within each study. Pooled effect sizes were then calculated for six commonly segmented knee compartments.

Results

55 articles met eligibility criteria. There was considerable variability between scanners, coils, software, scanning protocols, pulse sequences, and post-processing. Moderate risk of bias due to lack of blinding was common. Pooled effect sizes indicated participants at risk for knee OA had lengthened T2 relaxation time in all compartments (SMDs from 0.33 to 0.74; p < 0.01) and lengthened T1ρ relaxation time in the femoral compartments (SMD from 0.35 to 0.40; p < 0.001).

Conclusions

T2 and T1ρ relaxation distinguish participants at risk for knee OA from healthy controls. Greater standardization of MRI methods is both warranted and required for progress towards biomarker validation.

Electronic supplementary material

The online version of this article (10.1186/s12891-019-2547-7) contains supplementary material, which is available to authorized users.

Long-term results of posterior cruciate ligament tear with or without reconstruction: A nationwide, population-based cohort study

BACKGROUND

There is increasing interest in the long-term outcomes of patients with posterior cruciate ligament (PCL) tears following conservative treatment or reconstruction. However, limited information is available regarding these results because of the relative rarity of cases and lack of long-term follow-up.

PURPOSE

The goals of this study are to (1) compare the occurrence of secondary meniscal tears, osteoarthritis (OA) or subsequent total knee replacement (TKR) in patients with or without PCL injury, and (2) evaluate the potential protective effect of PCL reconstruction against long-term sequela in patients with PCL deficiency.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

This retrospective cohort study evaluated the long-term results of PCL deficiency with or without reconstruction in Taiwan based on data from the National Health Insurance Research Database (NHIRD) from 2000 to 2015. The cumulative incidence rates of meniscus tear, OA and TKR were analyzed using the Kaplan-Meier estimator. Cox proportional hazards models were applied to estimate hazard ratios (HRs) and 95% confidence intervals (CIs).

RESULTS

A total of 4,169 patients diagnosed with PCL tear from 2000 to 2015 in Taiwan were included in the study. There was a higher cumulative incidence of meniscus tear (1.13%), OA (2.71%) and subsequent TKR (0.91%) among patients with a PCL tear than among patients without one (0.22%, 1.90%, 0.62%; all p < 0.05). PCL reconstruction patients had a decreased cumulative incidence of meniscus tear (0.41%), OA (2.30%) and subsequent TKR (0.48%) compared with non-reconstructed patients (2.44%, 3.46%, 1.69%; all p < 0.05). After adjusting for covariates, PCL-injured patients who underwent reconstruction within one year after PCL injury showed a significantly lower risk of subsequent sequelae than those who never underwent reconstruction (within 1 month: adjusted HR = 0.390, 95% CI = 0.284-0.535; 1 month to 1 year: adjusted HR = 0.546, 95% CI = 0.398-0.748).

CONCLUSIONS

Patients with PCL tears have a significantly higher risk of meniscus tear, OA and subsequent TKR than patients without PCL tears. PCL reconstruction could decrease the cumulative incidence of these outcomes. The results suggest that PCL-injured patients should undergo reconstruction as early as possible (within one year) to reduce the risk of further degeneration.

Posterior Cruciate Ligament Injuries of the Knee at the National Football League Combine: An Imaging and Epidemiology Study

PURPOSE

To determine the epidemiology by player position, examination, imaging findings, and associated injuries of posterior cruciate ligament (PCL) injuries in players participating in the National Football League (NFL) Combine.

METHODS

All PCL injuries identified at the NFL Combine (2009-2015) were reviewed. Data were obtained from the database organized by the NFL medical personnel for the compilation of the medical and physical performance examination results of NFL Draftees participating in the NFL Combine from 2009 to 2015. Inclusion criteria were any player with clinical findings or a previous surgery consistent with a PCL injury who participated in the NFL Combine.

RESULTS

Of the 2,285 players who participated in the NFL Combine between 2009 and 2015, 69 (3%) had evidence of a PCL injury, of which 11 players (15.9%) were managed surgically. On physical examination, 35 players (52%) had a grade II or III posterior drawer. Concomitant injuries were present frequently and included medial collateral ligament (MCL; 42%), anterior cruciate ligament (ACL; 11.6%), and chondral injuries (31.8%), especially in the lateral tibiofemoral compartment.

CONCLUSIONS

Three percent of the players at the NFL Combine presented with a PCL injury, with a significant amount being either running backs (14/69, 20.2%) or offensive linemen (14/69, 20.2%). Approximately half of the players with a PCL tear had a residual grade II or III posterior drawer after sustaining a PCL injury. Concomitant injuries were present frequently and included MCL (42%), ACL (11.6%), and chondral injuries (31.8%), especially in the lateral tibiofemoral compartment. For those players with clinical concern for PCL ligamentous laxity, there should be a complete comprehensive workup that includes plain and PCL stress view radiographs, and magnetic resonance imaging.

LEVEL OF EVIDENCE

Level IV, case series.

Incidence and long-term follow-up of isolated posterior cruciate ligament tears

PURPOSE

Isolated posterior cruciate ligament (PCL) tears are an uncommon injury. The goals of this study are to (1) determine the population-based incidence of isolated PCL tears, (2) compare the occurrence of secondary meniscal tears or arthritis in patients with PCL deficiency to patients without PCL tears, and (3) evaluate factors associated with long-term sequelae among patients with PCL deficiency.

METHODS

This retrospective study included a population-based incidence cohort of 48 patients with new-onset, isolated PCL tears between 1990 and 2010, as well as an age and sex-matched cohort of individuals without PCL tears. A chart review was performed to collect information related to the initial injury, treatment, and outcomes. Subjects were retrospectively followed to determine the development of subsequent meniscal tears, arthritis, or total knee arthroplasty (TKA).

RESULTS

The age- and sex-adjusted annual incidence of isolated, complete PCL tears was 1.8 (95 % CI 1.3, 2.3) per 100,000. During a mean 12.2-year follow-up, patients with isolated PCL tears had a significantly higher likelihood (HR 6.2, 95 % CI 1.8, 21.2) of symptomatic arthritis compared to individuals without PCL tears. The likelihood of subsequent meniscal tears (HR 2.1, 95 % CI 0.4, 10.7) and TKA (HR 3.2, 95 % CI 0.5, 19.6) was more frequent among patients with PCL tears compared to subjects without PCL tears. Older age at injury was significantly associated with future arthritis (P = 0.003) and TKA (P = 0.02).

CONCLUSION

Isolated PCL tears remain a rare injury with an estimated annual incidence of 2 per 100,000 persons. Patients with isolated PCL tears have a significantly higher risk of symptomatic arthritis than patients without PCL tears. Older age at injury is associated with a higher risk of arthritis and the need for TKA. The results of this study can be used to educate patients about the natural history of isolated PCL tears and provide a baseline of expectations for the future development of arthritis and subsequent meniscal injury following isolated PCL injury.

LEVEL OF EVIDENCE

Retrospective comparative study, Level III.

T1ρ Hip Cartilage Mapping in Assessing Patients With Cam Morphology: How Can We Optimize the Regions of Interest?

BACKGROUND

T1ρ MRI has been shown feasible to detect the biochemical status of hip cartilage, but various region-of-interest strategies have been used, compromising the reproducibility and comparability between different institutions and studies.

QUESTIONS/PURPOSES

The purposes of this study were (1) to determine representative regions of interest (ROIs) for cartilage T1ρ mapping in hips with a cam deformity; and (2) to assess intra- and interobserver reliability for cartilage T1ρ mapping in hips with a cam deformity.

METHODS

The local ethics committee approved this prospective study with written informed consent obtained. Between 2010 and 2013, in 54 hips (54 patients), T1ρ 1.5-T MRI was performed. Thirty-eight hips (38 patients; 89% male) with an average age of 35 ± 7.5 years (range, 23-51 tears) were diagnosed with a cam deformity; 16 hips (16 patients; 87% male) with an average age of 34 ± 7 years (range, 23-47 years) were included in the control group. Of the 38 patients with a cam deformity, 20 were pain-free and 18 symptomatic patients underwent surgery after 6 months of failed nonsurgical management of antiinflammatories and physical therapy. Exclusion criteria were radiologic sings of osteoarthritis with Tönnis Grade 2 or higher as well as previous hip surgery. Three region-of-interest (ROI) selections were analyzed: Method 1: as a whole; Method 2: as 36 to 54 small ROIs (sections of 30° in the sagittal plane and 3 mm in the transverse plane); Method 3a: as six ROIs (sections of 90° in the sagittal plane and one-third of the acetabular depth in the transverse plane: the anterosuperior and posterosuperior quadrants, divided into lateral, intermediate, and medial thirds); and Method 3b: as the ratio (anterosuperior over posterosuperior quadrant). ROIs in Method 3 represent the region of macroscopic cartilage damage, described in intraoperative findings. To asses interobserver reliability, 10 patients were analyzed by two observers (HA, GM). For intraobserver reliability, 20 hip MRIs were analyzed twice by one observer (HA). To assess interscan reliability, three patients underwent two scans within a time period of 2 weeks and were analyzed twice by one observer (HA). T1ρ values were compared using Student's t test. Interclass correlation coefficient (ICC) and root mean square coefficient of variation (RMS-CV) were used to analyze intraobserver, interobserver, and interscan reliability.

RESULTS

Patients with a cam deformity showed increased T1ρ values in the whole hip cartilage (mean: 34.0 ± 3.8 ms versus 31.4 ± 3.0 ms; mean difference: 2.5; 95% confidence interval [CI], 4.7-0.4; p = 0.019; Method 1), mainly anterolateral (2), in the lateral and medial thirds of the anterosuperior quadrant (mean: 32.3 ± 4.9 ms versus 29.4 ± 4.1 ms; mean difference: 3.0; 95% CI, 5.8-0.2; p = 0.039 and mean 36.5 ± 5.6 ms versus 32.6 ± 3.8 ms; mean difference: 3.8; 95% CI, 6.9-0.8; p = 0.014), and in the medial third of the posterosuperior quadrant (mean: 34.4 ± 5.5 ms versus 31.1 ± 3.9 ms; mean difference: 3.1; 95% CI, 6.2-0.1; p = 0.039) (3a). The ratio was increased in the lateral third (mean: 1.00 ± 0.12 versus 0.90 ± 0.15; mean difference: 0.10; 95% CI, 0.18-0.2; p = 0.018) (3b). ICC and RMS-CV were 0.965 and 4% (intraobserver), 0.953 and 4% (interobserver), and 0.988 (all p < 0.001) and 9% (inter-MR scan), respectively.

CONCLUSIONS

Cartilage T1ρ MRI mapping in hips is feasible at 1.5 T with strong inter-, intraobserver, and inter-MR scan reliability. The six ROIs (Method 3) showed a difference of T1ρ values anterolateral quadrant, consistent with the dominant area of cartilage injury in cam femoroacetabular impingement, and antero- and posteromedial, indicating involvement of the entire hip cartilage health. The six ROIs (Method 3) have been shown feasible to assess cartilage damage in hips with a cam deformity using T1ρ MRI. We suggest applying this ROI selection for further studies using quantitative MRI for assessment of cartilage damage in hips with a cam deformity to achieve better comparability and reproducibility between different studies. The application of this ROI selection on hips with other deformities (eg, pincer deformity, developmental dysplasia of the hip, and acetabular retroversion) has to be analyzed and potentially adapted.

LEVEL OF EVIDENCE

Level III, diagnostic study.

Effect of Posterior Cruciate Ligament Rupture on Biomechanical and Histological Features of Lateral Femoral Condyle

Background

The aim of this study was to investigate bone mineral density (BMD) and the biomechanical and histological effects of posterior cruciate ligament (PCL) rupture on the lateral femoral condyle.

Material/Methods

Strain on different parts of the lateral femoral condyle from specimens of normal adult knee joints, including 12 intact PCLs, 6 ruptures of the anterolateral bundle, 6 ruptures of the postmedial bundle, and 12 complete ruptures, was tested when loaded with different loads on the knee at various flexion angles. Lateral femoral condyles were also collected randomly from both the experimental side in which the PCLs were transected and the control side from 4 sets of 12 matched-mode pairs of rabbits at 4, 8, 16, and 24 weeks after surgery, and their BMD and morphological and histological changes were observed.

Results

Partial and complete rupture of the PCL may cause an abnormal load on all parts of the lateral femoral condyle with any axial loading at all positions. Noticeable time-dependent degenerative histological changes of the lateral femoral condyle were observed in the rabbit model of PCL rupture. All of the PCL rupture groups had a higher expression of matrix metalloproteinase-7 (MMP-7) and collagen type II than the control group at all time points (P<0.05), but no significant difference in BMD (P>0.05).

Conclusions

Rupture of the PCL may trigger a coordinated response of lateral femoral condyle degeneration in a time-dependent manner, to which the high level of expression of MMP-7 and collagen type II could contribute.

The influences of different spatial resolutions on the characteristics of T2 relaxation times in articular cartilage: A coarse-graining study of the microscopic magnetic resonance imaging data

Microscopic magnetic resonance imaging (µMRI) T2 data from canine cartilage at different tibial locations were analyzed to investigate the influences of spatial resolution and pixel position on the T2 sensitivity to osteoarthritis (OA). Five experimental factors were investigated: inaccurate pixel position, different pixel resolutions, different specimen orientations in the magnetic field, topographical variations over the tibial surface, and different OA stages. A number of significant trends were identified in this analysis, which shows the subtle but substantial influences to our abilities of detecting OA due to T2 changes. In particular, any deviation in locating the cartilage pixels may result in erratic values near the cartilage surface. Significant differences were found in T2 values between nearly any two comparison-groups under all resolutions both in the meniscus-covered and -uncovered areas, which were also showed interaction between the OA degradation stages. This multiresolution project should help to improve the detection sensitivities of MRI toward cartilage degeneration. Microsc. Res. Tech. 79:754-765, 2016. © 2016 Wiley Periodicals, Inc.

T1ρ MRI detects cartilage damage in asymptomatic individuals with a cam deformity

Hips with a cam deformity are at risk for early cartilage degeneration, mainly in the anterolateral region of the joint. T1ρ MRI is a described technique for assessment of proteoglycan content in hyaline cartilage and subsequently early cartilage damage. In this study, 1.5 Tesla T1ρ MRI was performed on 20 asymptomatic hips with a cam deformity and compared to 16 healthy control hips. Cam deformity was defined as an alpha angle at 1:30 o'clock position over 60° and/or at 3:00 o'clock position over 50.5°. Hip cartilage was segmented and divided into four regions of interest (ROIs): anterolateral, anteromedial, posterolateral, and posteromedial quadrants. Mean T1ρ value of the entire weight bearing cartilage in hips with a cam deformity (34.0 ± 4.6 ms) was significantly higher compared to control hips (31.3 ± 3.2 ms, p = 0.050). This difference reached significance in the anterolateral (p = 0.042) and posteromedial quadrants (p = 0.041). No significant correlation between the alpha angle and T1ρ values was detected. The results indicate cartilage damage occurs in hips with a cam deformity before symptoms occur. A significant difference in T1ρ values was found in the anterolateral quadrant, the area of direct engagement of the deformity, and in the posteromedial quadrant. To conclude, T1ρ MRI can detect early chondral damage in asymptomatic hips with a cam deformity. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:1004-1009, 2016.

Characterization of Biochemical Cartilage Change After Anterior Cruciate Ligament Injury Using T1ρ Mapping Magnetic Resonance Imaging

BACKGROUND

Patients with anterior cruciate ligament (ACL)-injured knees are at an increased risk of posttraumatic osteoarthritis (OA). OA changes secondary to ACL injuries have many variations, and when and where early cartilage degenerative change begins has not yet been established.

PURPOSE

To characterize the location of cartilage degeneration after ACL injury associated with time since injury using T1rho (T1ρ) mapping.

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

In this study, 49 knees with ACL injuries and 14 normal knees from uninjured volunteers were imaged with a 3.0-T magnetic resonance scanner. Three regions of interest (ROIs) were defined in the cartilage at the weightbearing area of the femoral condyles (anterior, middle, and posterior zones). Two ROIs were defined in the tibial plateau (anterior and posterior zones). The T1ρ values within the ROIs were measured. Patients were allocated into 3 groups based on time since injury: <12 weeks (group A; 28 patients), 12 weeks to 2 years (group B; 14 patients), and >2 years to 5 years (group C; 7 patients).

RESULTS

Mean T1ρ values were significantly greater in the anterior and middle ROIs of the medial femoral condyle in group C compared with those in other groups (P < .05). Patients with medial meniscus injury, for whom the time since injury was ≥12 weeks, exhibited significantly greater T1ρ values in the middle areas of the medial femoral condyle versus normal knees and ACL-injured knees without medial meniscus injury.

CONCLUSION

The risk of cartilage degeneration in the area of the femoral condyle that contacts the tibia during small degrees of flexion increased when the time since injury was longer than 2 years. In addition, medial meniscus injury was associated with cartilage degeneration at the medial femoral condyle in the chronic phase.

CLINICAL RELEVANCE

Cartilage degeneration occurs more than 2 years after ACL injury and increases with medial meniscus injury. Early intervention may be desirable for meniscus injury.