The Animal Experimental And Clinical Correlated Studies Of The Influence Of Joint Hypermobility On The Femoral Trochlea

Part one An Experimental Study on the effect of Patellar Maltracking on the Development of Femoral Trochlea in Growing RatsObjective: This animal study aimed to explore the effects of patellar hypermobility and patellar dislocation on the developing femoral trochlea.Methods: Seventy-two 3-week-old Wistar rats were randomly divided into three groups.The sham group(SG)underwent simple incision and suture of the skin and subcutaneous tissue;the patellar hypermobility group(PHG)underwent medial and lateral retinacular release;the patellar dislocation group(PDG)underwent plication of the medial patellofemoral retinaculum.Twelve rats in each group were euthanized at 3 and 6 weeks postoperatively,respectively,and specimens were collected.The bony sulcus angle(BSA),cartilaginous sulcus angle(CSA),trochlear sulcus depth(TSD),and thickness of the cartilage on the lateral facet(CTL),medial facet(CTM),and center(CTC)of the trochlea were measured on hematoxylin and eosin-stained sections.Results: In the PHG and PDG,the femoral condyles became blunt,the trochlear groove became shallower,and cartilage became thicker compared with the SG.Compared with the SG,the PHG and PDG had significantly larger BSA and CSA values at 3(P<0.05)and 6 weeks(P<0.005),and a significantly shallower TSD(P<0.05).At 3 weeks,all cartilage thicknesses in the PHG and the CTC and CTM in the PDG were significantly thinner than in the SG(PHG vs SG: P=0.009 for CTL,P<0.001 for CTM,P=0.003 for CTC;PDG vs SG: P=0.028 for CTC,P=0.048 for CTM).At 6 weeks,the CTC was thicker in the PHG and PDG than the SG(PHG vs SG: P=0.044;PDG vs SG:P=0.027),and the CTL was thinner in the PDG than the SG(P=0.044).Conclusions: Patellar hypermobility and patellar dislocation may result in trochlear dysplasia that worsens with age.Excessive or insufficient stress leads to trochlear dysplasia.Part Two Correlation Analysis of Global Joint Hypermobility and Femoral Trochlea DysplasiaObjective: Anterior knee pain is the most common knee disorder in young adults.Global Joint Hypermobility(GJH)is a risk factor for patellar instability.Patients presenting with anterior knee pain were examined to evaluate whether GJH is a risk factor for trochlear dysplasia.Methods: Patients(18-40 years old)with anterior knee pain were examined by magnetic resonance imaging(MRI)of the affected knee in in Baoding No.1 central hospital from November 2022 to January 2023.The Beighton score was hired to evaluate the joint hypermobility.Sulcus angle(SA),Trochlear sulcus depth(TSD),Trochlear facet asymmetry(TFA)and Insall-Salvati index were measured and Dejour classification was performed on the MRI to assess femoral dysplasia.Results: Among the 100 patients observed,23 patients had femoral trochlear dysplasia,77 patients had normal trochlea,13 patients were diagnosed with GJH,and 7 patients were found to have dysplasia combined with GJH.Female gender(X2=8.036,P=0.005)and GJH(X2=8.028,P=0.005)were associated with femoral trochlea dysplasia.Female gender(OR=0.121-0.950,P<0.05)and GJH(OR=0.066-0.816,P<0.05)were risk factors for femoral trochlear dysplasia.The risk of femoral trochlear dysplasia in GJH patients was 2.29 times higher than that in non-GJH.GJH patients had larger SA and shallower TSD.Pearson correlation analysis showed that the level of Beighton score had a significant positive correlation with SA(r=0.273,P<0.01),and had a significant negative correlation with TFA(r=-0.239,P<0.05)and TSD(r=-0.275,P<0.01).Conclusions: For young adults with anterior knee pain,GJH is a risk factor for femoral trochlear dysplasia,a youth with GJH has a 2.29-fold increased risk of having trochlear dysplasia.Part Three T2 Values of Articular Cartilage in Patellofemoral and Tibiofemoral in Young Adults with Global Joint HypermobilityObjective: This study was performed to evaluate cartilage within the knee joint in global joint hypermobility(GJH)patients,using elevated magnetic resonance imaging-based T2 relaxation times(T2RT)as an indicator of low collagen.Methods: Thirty-six GJH patients and 30 healthy control patients,recruited with Beighton score,were evaluated with T2 mapping sequence.The collagen differences in the cartilage of 18 subregions of the medial and lateral tibiofemoral compartment and tibiofemoral compartment between the two groups of patents were quantitatively evaluated with T2 relaxation time(T2RT).Results:1.In the medial tibiofemoral compartment,the T2 RT of the medial femoral condyle in the GJH group and the control group showed the longest cartilage in the central region,followed by the anterior cartilage,and the shortest T2 RT of the posterior cartilage;The T2 RT of the medial condylar cartilage of the tibial plateau in all patients showed that the central region was higher than the anterior cartilage,and the posterior cartilage had the shortest T2 RT.There was no statistically significant difference in T2 RT between the two groups of patients in the medial posterior condylar region of the femur and the medial posterior tibial plateau region(P>0.05).The T2 RT of the cartilage in the GJH group was significantly higher than that in the control group in the anterior and central medial condyles of the femur,medial anterior and central tibial plateau regions(P<0.05).Especially in the medial central region of the femoral condyle and tibial plateau,the T2 RT of the cartilage was statistically significant at 0.001 level.2.In the lateral tibiofemoral compartment,the T2 RT values of the lateral femoral condylar cartilage in both groups decreased sequentially from the anterior to posterior directions.Compared with the control group,the T2 RT of the cartilage in the anterior,posterior,and central regions of the lateral femoral condyle in the GJH group was significantly higher than that in the control group(P<0.05).However,the cartilage T2 RT value in the anterior lateral tibial plateau region was significantly higher in the GJH group than in the control group(P=0.015),on the tibial side,and there was no statistical difference between the central and posterior lateral tibial plateau regions.3.The T2 RT of the six cartilage subregions in the patellofemoral compartment in GJH group was significantly higher than that in the control group(P<0.000).Especially in the center of the patella and the lateral area of the femoral trochlea,the T2 RT of the cartilage was statistically significant at 0.001 level.Conclusions: GJH is associated with early cartilage degeneration in multiple regions of the patellofemoral and tibiofemoral joints,Compared with the healthy control group.The range of early cartilage degeneration caused by GJH is diffusional.For patients with GJH,active measures should be taken to prevent early cartilage damage from progressing to osteoarthritis.