I.

Purpose: (1) To identify bone-shape changes from baseline to 3-years after anterior cruciate ligament reconstruction (ACLR). (2) to assess association between changes in bone-shape from baseline to 6-months and changes in cartilage matrix and patient functions and symptoms from baseline to 3-years after ACLR. Methods: Bilateral knees of 30 patients with unilateral ACL injuries were scanned at baseline, 6-months, 1-, 2-, and 3-years after ACLR. Bilateral knees of 13 controls were scanned at baseline, 1-and 3-years. Mean T1r and T2 values of each cartilage compartment were computed. Bone shape was quantified using statistical shape modeling (SSM) and 3D-MRI. Patient functions and symptoms were evaluated using Knee Injury and Osteoarthritis Outcome Score (KOOS). Results: Statistically significant changes were observed in Femur 2 (medial femoral condyle [MF] shape), Femur 6 (intercondylar notch width), Tibia 1 (tibia plateau area), and Tibia 7 (medial tibia slope) over 3-years after ACLR. Statistically significant differences were observed between injured and control knees in several modes. Statistically significant correlations were found between changes in bone shape (DFemur 6, DFemur 8 [trochlea inclination and MF height], DTibia 1) from baseline to 6-months and that of cartilage T1r and T2 and KOOS from baseline to 3-years after ACLR. Conclusion: Bone shape remodeling occurs after ACLR, and early bone shape changes (within 6 months) correlated with cartilage matrix and patient outcomes at 3-years after ACLR. Bone shape can be a promising imaging biomarker that stratifies patients at high risk for post-traumatic osteoarthritis (PTOA).

Background The present study aims to describe the imaging features in incident radiographic patellofemoral osteoarthritis (RPFOA) population in a Chinese suburban area. Methods The Beijing Shunyi osteoarthritis (BJS) study was a population-based, longitudinal and prospective study. Residents were recruited by randomized cluster sampling in 2014 and were followed 3 years later. Home interviews and clinical examinations were performed; weight-bearing posterior-anterior semi-flexed (45-degree) views of the tibiofemoral (TF) joints and skyline (45-degree) views of the patellofemoral (PF) joints were included. For each batch of study films ( n = 100), 20 films from the year 2014 and 20 previously read PF radiographs were fed back to test inter−/intra-reader repeatability. The imaging features of incident RPFOA were analyzed. Narrative statistics, independent-sample t-tests, and nonparametric tests were performed. Results A total of 1295 participants (2590 knees) were recruited at baseline in 2014, and 967 (74.7%) residents were followed in 2017. Of all the knees ( n = 1537) without RPFOA at baseline, 139 knees (13.3%) across 119 people developed incident RPFOA. Compared with the whole population, age ( p = 0.031), body mass index (BMI, p = 0.042), and incidence of knee pain symptoms ( p < 0.01) were significantly different in the incident RPFOA population, while range of motion (ROM, p = 0.052) and gender (0/1, p = 0.203) showed no significance. In the incident population, the changes of each imaging indicator grade were evaluated—lateral patellofemoral osteophyte (LPOST, increased by 1.02), medial patellofemoral osteophyte (MPOST, increased by 0.49), lateral joint space narrowing (LJSN, increased by 0.30), medial joint space narrowing (MJSN, increased by 0.06); indicator grade progress decreases, respectively. The progress of LPOST was the fastest among the four indicators ( p < 0.01). Conclusions In this population-based longitudinal study, among the incident RPFOA population, the imaging indicators show that marginal patellofemoral osteophyte is more pronounced than patellofemoral joint space narrowing. LPOST is the fastest-progressing indicator among all the radiographic features, which is also the most common imaging manifestation of RPFOA. In the incident RPFOA population, the proportion of elders, women, higher-BMI individuals, and people suffering knee pain is more than the normal population.

No abstract

Purpose: Bone geometry plays an important role in joint biomechanics and pathogenesis of osteoarthritis. To date, no studies have evaluated directly the association between cartilage thickness and bone shape. The goals of this present study are tow-fold: 1) To investigate the distribution of cartilage thickness and bone shape among different Kellgren-Lawrence (KeL) gradings; and 2) to explore the correlation between bone shape and cartilage thickness. Methods: 50 patients (54.92 ± 11.62 years, BMI 24.37 ± 2.96 Kg/m 2 , 25 females) were scanned by 3.0 T MRI at our hospital (10 knees for each KeL grading from 0e4, matched by age, gender and BMI between KL grades). MRI imaging protocols included sagittal T1 fast spin echo (FSE) and sagittal fat-suppressed 3D fast spoiled gradient echo (FSPGR). Cartilage was segmented semi-automatically on FSPGR images into lateral/medial femoral condyle (LF/MF), lateral/medial tibia (LT/MT), patella (P) and trochlea (TRO) using in-house developed software. The average thickness was calculated for each compartment. The tibia and femur were segmented semi-automatically on FSE images, and the bone shape was quantified using statistical shape modeling (SSM) as developed in-house previously. Principal component analysis (PCA) of automatically defined and matched 3D landmarks was used to extract a compact signature of the shape. The first 20 femur and tibia modes were analyzed (T1eT20, F1eF20). The difference of cartilage thickness and bone shape modes among the 5 groups were analyzed by using ANOVA, respectively. Partial Pearson Correlation was calculated to explore the correlation between cartilage thickness and bone shape, adjusted for age, gender, BMI and K-L grading. The level of significance was P < 0.01. Results: Significance was observed in the cartilage thickness of patella and MT among the 5 KL groups (Figure 1A), and in one femur (F5) and two tibia (T6, T7) bone shape modes (Figure 1B). The area of tibia plateau increased from KeL 2 to K-L 4 (T7); posterior slope to tibia plateau increased from KeL 1 to K-L 2 (T6); The contour of medial femoral condyle differed contrarily between from KeL 0 to KeL 2 and from KeL 2 to KeL 4 (F5). There are correlations between cartilage thickness and bone shape in three femur (F10, F11, F16) and two tibia (T5, T18) modes (Table 1). Increasing medially of MF (F10) and increasing posteriorly of LF (F11) as well as increasing superiorly of intercondylar eminence (T18) are associated with more cartilage degeneration at LT (thinner cartilage). Increasing inferiorly of trochlea groove (F11) is associated with more cartilage degeneration at femoral trochlea. Increasing of tibia plateau is associated with more cartilage denegation at MT. Figure 2 illustrates the physical meaning of the bone shape modes with significance. Conclusions: Statistical shape model and 3 D MRI are powerful tools for quantifying bone shapes. Significant correlation was found between bone shapes, especially increasing medially of MF, increasing posteriorly of LF, increasing super...

No abstract

Background:An altered tibial position is still present despite anterior cruciate ligament (ACL) reconstruction. It has been demonstrated that an abnormal tibial position after an ACL injury may play a role in subsequent injuries to the meniscus, which can lead to early cartilage degeneration.Purpose:To determine changes in both the tibial position and the meniscal matrix present before and after ACL reconstruction as well as to evaluate the association between these 2 variables in ACL-injured knees 3 years after reconstruction.Study Design:Cohort study; Level of evidence, 2.Methods:Bilateral knee magnetic resonance imaging (MRI) of 32 patients with unilateral ACL injuries was performed before reconstruction; 13 control participants also underwent MRI. Follow-up MRI was performed up to 3 years after surgery. Tibial position, internal tibial rotation, and T1ρ and T2 values of the menisci were calculated using an in-house MATLAB program. Student t tests and multiple linear regression were used to compare differences between injured, uninjured, and control knees as well as to assess correlations between the tibial position at 3 years and 3-year changes in quantitative MRI meniscal relaxation values.Results:The tibial position of injured knees was more anterior than that of uninjured knees at baseline, 6 months, and 1, 2, and 3 years (P < .05 for all). The T1ρ and T2 values of the menisci of injured knees were greater than those of uninjured and control knees in the posterior lateral and posterior medial horns up to 1 and 2 years after surgery, respectively (P < .05 for all). The tibial position at 3 years was associated with increased T2 values from baseline to 3 years in the posterior medial horn (β = 0.397; P = .031) and anterior medial horn (β = 0.360; P = .040).Conclusion:Results of the current study indicate that there is a persistently altered tibial position after ACL reconstruction. Initial preoperative meniscal abnormalities show prolonged but gradual improvement. Additionally, correlations between the tibial position and changes in the medial meniscal matrix suggest that the tibial position may play a role in the increased susceptibility to medial meniscal tears seen after reconstruction. The development of newer surgical techniques must address a persistently altered tibial position. Quantitative MRI is an effective instrument to evaluate meniscal matrix changes and can serve as an early radiological tool for meniscal injuries.

No abstract