Patella morphological alteration after patella instability in growing rabbits

Abstract

BackgroundThe shape of the patella has been considered to be a predisposing factor resulting in patellar instability, but the effects of abnormal patella position during its development are unclear. The present study evaluated patellar morphological changes after patella instability and evaluated the influence of patellar instability on the patella shape.MethodsTwenty rabbits that were 2 months old were included in the study. The left knee of each rabbit, defined as the experimental group (N = 20 knees/group), underwent a medial soft tissue restraint release. The right knee of each rabbit, defined as the control group (N = 20 knees/group), did not undergo any surgical procedures. A CT scan was performed on each knee before surgery and 6 months post-surgery to measure the transverse diameter, thickness, Wiberg index, and Wiberg angle for analysis of the patellar morphological changes. Cross-specimen examination was conducted to evaluate the differences between the experimental group and the control group.ResultsThe four indices remained the same between the two groups before surgery. However, 6 months after surgery, the mean transverse diameter of the patellae in the experimental group was significantly longer than that in the control group (P < 0.001), while the mean thickness in the experimental group was not significantly greater than that in the control group (P = 0.314), resulting in a flattened shape. The Wiberg indices were not significantly different between the two groups. However, the mean Wiberg angle was higher in the experimental group than in the control group (P < 0.001), which resulted in a flattened articular surface of the patella.ConclusionThe sectional shape and articular surface of the patella became more flattened after patella instability in this study, which indicates that patella dysplasia could be caused by patella instability. Clinically, early intervention for adolescent patients with patella instability is important.

The torsional alignment changed significantly in growing rabbits after patella dislocation by a three-dimensional measurement

“…Just like the previous animal experiments [7,8,9,10,11], the outcomes of the studies indicates that the aberrant version of the femur may not only be the risk factor for patella dislocation, but also be the consequence of patella dislocation. After patella dislocation in growing rabbits, the morphology of patella, femoral trochlea and the version of the femur were found changed signi cantly.…”

“…Previous animal studies have investigated the in uence of patella instability on the morphological development of the patellofemoral joint. Wang, Li and Niu observed femoral trochlear dysplasia and patellar dysplasia could occur after patella dislocation in growing rabbits [7,8,9]. Kaymaz reported after surgery for patella alta in growing rabbits, trochlea attening was found [10].…”

The Morphology of Patella changed significantly after Soft Tissue Correction for children with Recurrent Patella Dislocation

“…In the present study, the Wiberg-index and Wiberg-angle in the control group are almost same before surgery and at the last follow-up, which is consistent with the previous studies. On the other hand, the patella and femoral trochlea dysplasia can occur after patella dislocation [14,15,16]. This study and the study by Fu [18] showed signi cant morphological alteration of patella and femoral trochlea after surgical correction in the children with recurrent patella dislocation.…”

“…Combined with the previous study [14,15,16,18], the normal patella position with femoral trochlea is important for the patellofemoral development. Patellar and femoral trochlear dysplasia can occur after patella dislocation [14,15].…”

“…Li and Wang found femoral trochlear dysplasia after patella dislocation in growing rabbits [14,15]. Niu found the axial shape and articular surface of the patella became more attened after patella instability in growing rabbits [16]. These studies indicate that patellofemoral joint dysplasia could be caused by patella dislocation.…”