| Part One Anatomical Characteristics of Femoral Trochlear Groove Angle and the Effect of Patellofemoral Arthroplasty on Femoral Trochlear Groove AngleObjective: To understand the anatomical characteristics of the trochlear groove Angle.The effect of patellofemoral arthroplasty on the trochlear groove angle was studied by computer simulation.Methods: 50 volunteers(25 males and 25 females)underwent lower extremity knee CT.Mimics 3D reconstruction was used to measure the trochlear groove angle,the angle between the trochlear groove line and the anatomical axis of the femur,the mechanical axis of the femur,and the femoral trochlear inclination angle.Results: The femoral trochlea groove angle was 2.8±2.3°.The angle between the line of the trochlea and the mechanical axis of the femur was2.7±1.8°.The angle between the line of the trochlea and the anatomical axis of the femur was 8.1±2.1°.The femoral trochlear inclination angle was13.4±3.2°.The femur trochlear groove angle was medial in the coronal plane.After the simulated patellofemoral arthroplasty,the femoral trochlear groove Angle was-5.9° when the prosthesis was rotated by 0°.Conclusions: In healthy people,the femoral trochlear groove angle was2.8±2.3° and toward to medial in the coronal plane.The trochlear groove Angle was-5.9° and toward to lateral after patellofemoral arthroplasty.The rotation of the patellofemoral prosthesis affects the changes of trochlear groove angle and osteotomy volume.Part Two Effect of Prosthesis Rotation on Patellofemoral Biomechanics after Patellofemoral ArthroplastyObjective: To analyze the effect of prosthesis rotation on the contact pressure of the patellofemoral joint after patellofemoral arthroplasty by the three-dimensional finite element method.Methods: The three-dimensional finite element model of the normal knee joint was established.The appropriate prosthesis model was selected.The femoral trochlear osteotomy was performed parallel to the femoral surgical transcondylar axis.The patellofemoral arthroplasty was simulated by Boolean operation.A 0 ° rotation model was established,and then seven different three-dimensional models of the knee joint after patellofemoral joint replacement were obtained by internal rotation of 2 °,internal rotation of 4 °,internal rotation of 6 °,external rotation of 2 °,external rotation of 4 °,and external rotation of 6 °.The same conditions were set to analyze the changes of the contact pressure of the patellofemoral joint.Results: The stress of the patellofemoral joint increased after patellofemoral arthroplasty.With the change of external rotation of the prosthesis,the stress of the medial patellofemoral joint increased and the lateral patellofemoral joint decreased.With the change of internal rotation of the prosthesis,the stress of the lateral patellofemoral joint increased,while the stress value of the medial patellofemoral joint decreased.When the prosthesis was internally rotated by 6°,the maximum stress of the patellofemoral joint increased by 64.6%.The stress value of the patellofemoral joint increased by49.7% at 6° of prosthesis external rotation.Conclusions: During patellofemoral arthroplasty,different rotations of the prosthesis affect the pressure of the patellofemoral joint,and abnormal internal or external rotation of the prosthesis increases the pressure of the patellofemoral joint.Part Three Effect of Prosthesis Rotation on Clinical Outcome after Patellofemoral ArthroplastyObjective: Patellofemoral osteoarthritis is increasingly recognized as a cause of knee pain.Clinical and imaging data of patients undergoing patellofemoral arthroplasty with the Zimmer gender-solution prosthesis system was retrospectively analyzed to evaluate the clinical outcomes of patients and analyze the influence of prosthesis rotation on the clinical outcomes.Methods: Clinical and imaging data of patients who underwent patellofemoral arthroplasty for patellofemoral osteoarthritis using the Zimmer gender-solution patellofemoral prosthesis system in our hospital from January2015 to June 2020 were retrospectively analyzed.Patient-reported outcome methods included the Knee Society Score、Oxford Knee Score、Kujala Score、Range of Motion and Forgotten Joint Score to evaluate clinical function.Imaging evaluation was performed using an X-ray and CT of the knee.Results: A total of 61 patients were included in this study,with an average age of 56.6±4.3 years,including 15 males and 46 females.The mean BMI was 25.7 ± 4.6 kg/m2,and the mean follow-up time was 3.8 years.The clinical score of KSS significantly increased from 39.7±8.3 preoperative to87.8±9.5 at the last follow-up(p<0.05),and the functional score of KSS significantly increased from 40.5±9.4 preoperative to 90.8±8.6 points at last follow-up(p<0.05).OKS score significantly increased from 19.7±4.9preoperative to 41.3±4.2 points at the last follow-up(p<0.05).ROM increased from 96.3±8.5° preoperative to 115.7±9.2° at the last follow-up(p< 0.05).Kujala score increased significantly from 48.1±5.4 points preoperative to86.5±3.8 points at the last follow-up(p<0.05).The mean FJS at the last follow-up was 76±6.4 points.According to postoperative CT of the knee joint,the rotation Angle of the prosthesis was measured: There were 6 cases in the internal rotation group,47 cases in the 0-3° external rotation group,and 8cases in the greater than 3° external rotation group.Compared with the external rotation group,the clinical and functional scores of KSS,OKS,FJS,and Kujala scores in the internal rotation group were lower,with statistically significant differences,but there was no statistically significant difference in ROM.Conclusion: Patellofemoral arthroplasty using the Gender-Solutions prosthesis system for Patellofemoral osteoarthritis could achieve satisfactory clinical results.Internal rotation of patellofemoral prostheses could affect the clinical outcome and should be accurately placed intraoperatively.Part Four Clinical Effect of Patellofemoral Arthroplasty Combined with High Tibial Osteotomy for Patellofemoral OsteoarthritisObjective: To retrospectively analyze the clinical effect of patellofemoral arthroplasty combined with high tibial osteotomy in the treatment of patellofemoral osteoarthritis.We hypothesized that patellofemoral arthroplasty combined with high tibial osteotomy would produce good clinical outcomes for patients with patellofemoral osteoarthritis due to the minimally invasive nature of the surgery and the preserved kinematics of the knee.Methods: The clinical and imaging data of patients who received patellofemoral arthroplasty combined with high tibial osteotomy for patellofemoral osteoarthritis in our hospital from January 2018 to April 2020 were retrospectively analyzed.Patient-reported outcome methods included the Knee Society Score、Oxford Knee Score、Range of Motion and Forgotten Joint Score to evaluate clinical function.Imaging evaluation was performed using an X-ray of the knee.Results: A total of 9 patients underwent patellofemoral arthroplasty combined with high tibial osteotomy including two men and seven women.The mean follow-up time was 2.6 years.At the last follow-up,KSS clinical score and functional score were 90.3±8.5,90.8±7.8 respectively,Oxford knee score was 43.6±3.6,FJS was 71.2±10.2,and knee range of motion was130.4°±8.1°.All outcomes were significantly improved compared with those preoperative,and the difference was statistically significant.Hip-knee-ankle Angle changed from-9.3±2.1° to 2.2±1.2°.No complications such as prosthesis loosening,infection,or osteotomy nonunion occurred.Conclusions: This study shows that patellofemoral arthroplasty combined with high tibial osteotomy can achieve good clinical in patients with patellofemoral osteoarthritis.Combined surgery is a feasible treatment after a strict selection of indications. |
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