Correlation Between The Lower Limb Alignment And Osteochondral Degeneration Of The Knee

Objective: It is well known that the occurrence and progression of osteoarthritis(OA)is the result of local mechanical factors acting under systemic susceptibility.The abnormal load distribution of the knee joint caused by the deformity of the lower limb alignment can promote the progress of osteoarthritis,but the role of changes in the subchondral trabecular bone(STB)in this process has not been clearly understood.Based on the analysis of the tibial plateau specimens after total knee arthroplasty by using micro CT scanning and histomorphometry,we discussed the changes of STB with the limb alignment and its effect on osteoarthritis..Methods: Full-leg standing digital anteroposterior radiographs before total knee arthroplasty were collected to measure the hip-knee-ankle(HKA)angle of the affected limb.Micro-CT scans of tibial plateau specimens were performed to analyze the microstructure of the STB.Osteochondral specimens were prepared histologically to evaluate cartilage degeneration.Histomorphometry and immunohistochemical techniques were used to analyze the bone remodeling activity of the STB.The relationships between the HKA angle and the changes of STB and cartilage degeneration were analyzed.Results: The microstructure and bone remodeling activity of the tibial plateau STB and the OARSI score of cartilage degeneration were significantly related to HKA angles.With the increased HKA angles,the STB microstructure sclerosis was more pronounced,the remodeling of the STB was more active,and the cartilage degeneration score on the affected tibial plateau was higher.In addition,above trends were similar in the varus alignment and in the valgus alignment.Conclusion: Abnormal load distribution of the knee joint caused by the change of the lower limb alignment may promote the occurrence and progression of covered cartilage degeneration by changing the bone remodeling activity and microstructure of the tibial plateau STB.The methods of changing alignment and bone metabolism agents may become entry points for osteoarthritis occurrence and progression intervention.