Ultrashort echo time magnetization transfer imaging of knee cartilage and meniscus after long-distance running

OBJECTIVE

To assess the detection of changes in knee cartilage and meniscus of amateur marathon runners before and after long-distance running using a 3D ultrashort echo time MRI sequence with magnetization transfer preparation (UTE-MT).

METHODS

We recruited 23 amateur marathon runners (46 knees) in this prospective cohort study. MRI scans using UTE-MT and UTE-T2* sequences were performed pre-race, 2 days post-race, and 4 weeks post-race. UTE-MT ratio (UTE-MTR) and UTE-T2* were measured for knee cartilage (eight subregions) and meniscus (four subregions). The sequence reproducibility and inter-rater reliability were also investigated.

RESULTS

Both the UTE-MTR and UTE-T2* measurements showed good reproducibility and inter-rater reliability. For most subregions of cartilage and meniscus, the UTE-MTR values decreased 2 days post-race and increased after 4 weeks of rest. Conversely, the UTE-T2* values increased 2 days post-race and decreased after 4 weeks. The UTE-MTR values in lateral tibial plateau, central medial femoral condyle, and medial tibial plateau showed a significant decrease at 2 days post-race compared to the other two time points (p < 0.05). By comparison, no significant UTE-T2* changes were found for any cartilage subregions. For meniscus, the UTE-MTR values in medial posterior horn and lateral posterior horn regions at 2 days post-race were significantly lower than those at pre-race and 4 weeks post-race (p < 0.05). By comparison, only the UTE-T2* values in medial posterior horn showed a significant difference.

CONCLUSIONS

UTE-MTR is a promising method for the detection of dynamic changes in knee cartilage and meniscus after long-distance running.

KEY POINTS

• Long-distance running causes changes in the knee cartilage and meniscus. • UTE-MT monitors dynamic changes of knee cartilage and meniscal non-invasively. • UTE-MT is superior to UTE-T2* in monitoring dynamic changes in knee cartilage and meniscus.

Medial meniscal ossicles: Associated knee MRI findings in a multicenter case-control study

PURPOSE

The purpose of this study was to assess and compare the prevalence of meniscal, ligament and cartilage lesions on knee MRI in a series of age- and sex-matched patients with and without medial meniscal ossicle.

MATERIALS AND METHODS

Forty-two knee MRI examinations obtained in 42 patients (36 men, 6 women; mean age, 42.5±22.2 [SD] years; range: 19-65years) on which a medial meniscal ossicle was present were compared to 42 knee MRI examinations obtained in 42 age- and sex-matched patients (36 men, 6 women; mean age, 41.8±20.6 [SD] years; range: 19-65years) on which no medial meniscal ossicles were present. Two radiologists (R1, R2) blinded to the presence of meniscal ossicle by reading only the fat-saturated intermediate-weighted MR images separately assessed the presence of meniscal, ligament and cartilage lesions on these 84 knee MRI examinations. Prevalence of meniscal and ligament lesions and degree of cartilage degradation at MRI were compared between knees with and those without medial meniscal ossicle.

RESULTS

In knees with medial meniscal ossicle, R1 and R2 detected 33 (79%) and 38 (90%) medial meniscal lesions, respectively that involved the posterior root (n=25/32 for R1/R2), the posterior horn (n=19/14 for R1/R2) or the body (n=8/10 for R1/R2). The prevalence of posterior root tear (60% [25/42]/76% [32/42] for R1/R2) and that of anterior cruciate ligament (ACL) lesions (48% [20/42]/57% [24/42] for R1/R2) as well as the medial cartilage degradation score (3.35±0.87 [SD] for R1 and 3.92±0.78 [SD] for R2) were significantly greater in knees with than in knees without medial meniscal ossicle (root lesions: P<0.01 for both readers; ACL lesions and medial cartilage score: P<0.01 for both readers).

CONCLUSION

On MRI examination, knees with a medial meniscal ossicle demonstrate a greater frequency of medial posterior root tear and of ACL lesions and a greater degree of medial femoro-tibial cartilage degradation by comparison with knees without medial ossicle.

Predictors of Exercise Adherence in Patients With Meniscal Tear and Osteoarthritis

OBJECTIVE

To identify predictors of poor exercise adherence in patients with osteoarthritis (OA) and meniscal tear.

DESIGN

Secondary analysis of data gathered over the first 12 weeks in the Meniscal Tear in Osteoarthritis Research (MeTeOR) trial, a multicenter, randomized controlled trial.

SETTING

Seven referral centers.

PARTICIPANTS

Most of the patients in the MeTeOR trial (N=325 of 351) were included in the analysis, each of whom was aged ≥45 years and had a meniscal tear and osteoarthritic changes on imaging studies; 26 were excluded because of missing data from which to derive the primary outcome variable.

INTERVENTIONS

All patients received a structured, supervised exercise program focused on strengthening, along with prescribed home exercises; half were randomly assigned to also receive arthroscopic partial meniscectomy.

MAIN OUTCOME MEASURE

Poor exercise adherence through 12 weeks, defined as performing <50% of prescribed exercise.

RESULTS

Thirty-eight percent of the MeTeOR cohort showed poor exercise adherence. In the multivariate model, adjusting for treatment group, those who earned ≤$29,000 per year had 1.64 times the risk of nonadherence (95% confidence interval [CI], 1.10-2.43) than those who earned >$100,000 per year; and those without baseline pain with pivoting and twisting had 1.60 times greater risk of nonadherence than those with these symptoms (95% CI, 1.14-2.25).

CONCLUSIONS

Low income was associated with poor exercise adherence among patients aged ≥45 years with OA and a meniscal tear, as was absence of pain with pivoting and twisting. Our findings highlight the need for further research into exercise adherence and for interventions to enhance adherence among those with low incomes.

The natural history of the anterior knee instability by stress radiography

OBJECTIVE:

To analyze the anteroposterior displacement of the knee by means of stress radiography in individuals with unilateral anterior knee instability and relate to time of instability.

METHODS:

Sixty individuals with intact knees (control group) and 125 patients with unilateral anterior instability (AI group) agreed to participate in the study. Gender, age, weight, height, age at injury, time between injury and testing, and surgical findings are studied. Both groups are submitted to anterior and posterior stress radiographies of both knees. Anterior (ADD) and posterior displacement difference (PDD) were calculated between sides.

RESULTS:

In the control group ADD and PDD are in average, zero, whereas in the AI group ADD averaged 9.8mm and PDD, 1.92mm. Gender, age, weight, height, age at trauma and presence of menisci's lesions do not intervene in the values of ADD and PDD. Meniscal injuries increase with time. ADD and PDD do not relate with the presence or absence of associated menisci's lesions. The ADD and the PDD are related to each other and increase with time.

CONCLUSION:

There is a permanent anterior subluxation of the injured knee that is related to the amount of anterior displacement that increases with time. Level of Evidence III, Study Types Case-control study.

Correlation of histological examination of meniscus with MR images: focused on high signal intensity of the meniscus not caused by definite meniscal tear and impact on mr diagnosis of tears

Objective

To document the causes of high signal intensity of the meniscus which is not caused by definite meniscal tears on MR imaging, through correlation with histological examination.

Materials and Methods

For the correlation between the MR image and histology, we obtained prospectively 31 meniscal specimens from 21 patients. Proton density-weighted turbo spin-echo MR images were used. Minimal tear, thinning of the lamellar layer, degeneration of the central layer, and radial tie fibers were detected upon histological examination, and were correlated with the corresponding MR images.

Results

Minimal tear of the lamellar layer was seen in 60 zones out of 100 slides. On MR images, 29 (48.3%) of these 60 zones had high signal intensity. Thinning of the lamellar layer was seen in 24 zones, with 7 (29.2%) having high signal intensity. 57 central zones showed degenerative change in the central layer and high signal intensity on all corresponding MR images. Radial tie fibers in the central layer appeared as high signal intensity areas.

Conclusion

Minimal tear and thinning of the lamellar layer, degeneration and radial tie fibers of the central layer of the meniscus cause high signal intensity on MR images.

Early results of all-inside meniscal repairs using a pre-loaded suture anchor

OBJECTIVES

To report the clinical and radiological results of all-inside meniscal repairs using a pre-loaded suture anchor.

DESIGN

Case series.

SETTING

Regional hospital, Hong Kong.

PATIENTS

From January 2008 to June 2010, 51 patients with a mean age of 26 (range, 15-48) years with 57 meniscal tears underwent meniscal repair utilising the all-inside meniscal repair technique entailing a pre-loaded suture anchor. All tears were located at red-red or red-white zones. Concurrent anterior cruciate ligament reconstruction was performed in 37 (73%) of the patients. Patients were evaluated postoperatively based on the International Knee Documentation Committee score, clinical examination, and magnetic resonance imaging. Presence of locking, joint-line tenderness, effusion, and positive McMurray test were considered to indicate clinical failure.

RESULTS

The mean follow-up was 19 (range, 12-39) months. An average of 2 (range, 1 to 4) suture devices was used per patient. The mean tear size was 20 (range, 10-40) mm. In all, 10 (18%) of the tears had failed clinically and 11 (19%) appeared unhealed on postoperative imaging. The mean International Knee Documentation Committee score improved significantly from 62 preoperatively to 81 postoperatively (P<0.001). Patients with concurrent anterior cruciate ligament reconstruction had better corresponding scores postoperatively than preoperatively (mean, 83 vs 65, P<0.001). The clinical and radiological outcome was not related to the chronicity, location or length of the tear, or patient age. No postoperative extra- or intra-articular complications were encountered.

CONCLUSION

All-inside meniscal repair using a pre-loaded suture anchor is safe and effective, and yielded an 83% clinical and 81% radiological success rate.