Morphological Analysis Of The Patellofemoral Joint With Trochlear Dysplasia And Clinical Study Of Patellofemoral Arthritis Treated By Patellofemoral Arthroplasty

Part 1 CT-based morphological analysis of the posterior femoral condyle in patients with trochlear dysplasiaObjective: Patellofemoral instability is one of the most frequent problems requiring orthopaedic consultation.It occurs most commonly in adolescent.Trochlear dysplasia is one of the major predisposing factors associated with patellofemoral instability.Previous studies have focused on the morphological geometry of trochlea and patella,such as the sulcus angle,the depth of the groove,the position and tilt of patella.The inferior and posterior part of distal femur plays an important role in alignment and kinetics of the knee,especially for patients with patellofemoral instability or valgus knee.The anterior part of the distal femur in trochlear dysplasia has been well investigated;however,to date,posterior morphological characteristics have not been well studied.This study aimed to evaluate whether the posterior femoral condyle in patients with trochlear dysplasia differs from those without trochlear dysplasia.Methods: Computed tomography(CT)scans of 75 knees with trochlear dysplasia and 55 knees with normal anatomy of the patellofemoral joint were analyzed retrospectively.The width,length,and height of the condyle and its posterior part between the two groups were assessed by CT scans.The intra-class correlation coefficient(ICC)was used to evaluate interobserver and introobserver reliability.The independent Student's t-test was used to assess the statistical significance of the qualitative variables.Results: There were significant differences between trochlear dysplastic and normal knees.The trochlear dysplasia group had a larger medial posterior condyle and smaller lateral posterior condyle than the control group in three dimensions(P<0.05).Furthermore,proportion of the posterior condyle in the distal femur markedly differed between the two groups: in the trochlear dysplasia group,the medial posterior condyle accounted for a bigger proportion,while the lateral posterior condyle accounted for a smaller proportion(P<0.05).Summary: Patients with trochlear dysplasia have different posterior femoral condyles compared with those without trochlear dysplasia.Patients with this condition have bigger medial posterior condyles and smaller lateral posterior condyles.A greater amount of attention needs to be paid to this abnormality.Part 2 Morphological measurements of trochlea and posterior condyle in the rabbit with patellar dislocationObjective: Trochlea dysplasia and patellar malposition will lead to the patellofemoral instability.Many studies have measured the femoral trochlear and patella related to patellofemoral joint.These measurements are mostly focused on anterior part of the distal femur.Whether the posterior condyle of knee with trochlea dysplasia differs from those with normal knee is unknown.Previous animal experiments had confirmed that patellar dislocation could affect the development of trochlea,and the dysplasia of the trochlea could further resulted in patellofemoral instability.In this study,an animal model of patellar dislocation was established,and the trochlea and posterior condyle were measured to confirm that whether the morphology of trochlea and posterior condyle in patellar dislocation is different from the normal knee.Methods: 40 young New Zealand rabbits were selected and coded for this study,and then randomly divided into experimental group and sham operation group.The left knees of these rabbits were received the operation of patellar dislocation.The right knees of the two groups were intact as the control group.Three months after the operation,the animals were killed and the lower extremities were resected from the proximal femurs and marked.Computed tomography(CT)scans were conducted to measure the angle and depth of the trochlear groove.Then the soft tissue of all the specimens were removed and the cartilage of distal femur were retained.The width,length,height of the condyle and its posterior part were measured respectively.Histological observation was also conducted to analysis the specimens.Results: The angle of trochlear grooves in the experimental group were higher than that in the other two groups;the depth of trochlear groove in the experimental group were lower than that in sham operation group and control group,these differences were statistically significant measured on CT scans(P< 0.05).The lateral femoral condyle and posterior part of the experimental group is significantly smaller in width,length and height compared with the sham operation group and control group(P<0.05).Gross specimen observation indicated that the depth of femoral trochlea in the experimental group was shallow,the synovial was hyperplasia,the surface of the articular cartilage was rough,and the osteophyte was seen around the joints.Summary: The animal model found that the dislocation of the patella could lead to dysplasia of the trochlear and femoral condyle,which could result in the degeneration of the knee joint.Part 3 Comparison of different operations in the treatment of isolated patellofemoral arthritisObjective: Isolated patellofemoral arthritis is a common disease in clinical practice.Operative treatment is often indicated for patients who have experienced failed non-operative treatment and disabling pain.Surgical options for patellofemoral osteoarthritis(OA)include patellofemoral joint debridement,anterior tibia tubercle elevation,joint replacement and so on.Although total knee arthroplasty(TKA)has been reported to provide pain relief and functional improvement in this population,many surgeons prefer a less invasive procedure.With the development of surgical techniques and instruments,patellofemoral arthroplasty(PFA)is becoming more and more successful.This study retrospectively analyzed the clinical outcomes of patients with isolated patellofemoral arthritis treated by total knee arthroplasty,patellofemoral arthroplasty and arthroscopic debridement.Methods: Patients with isolated patellofemoral arthritis underwent surgical procedures at the Third Hospital of Hebei Medical University were retrospective analysis.There were 15 cases underwent total knee arthroplasty,9 cases underwent the PFA,and 11 cases underwent arthroscopic debridement.The operative time,length of stay,preoperative and postoperative Visual Analogue Scale(VAS),American knee society knee score(KSS),Range of motion(ROM)of the knee were compared to assess the clinical outcomes of three operative methods on isolated patellofemoral arthritis.Results: All the operations were successfully completed without surgical or internal complications.There was a significant difference in the operative time and length of stay between the groups,the arthroscopic group required the shortest operative time and stay in hospital,while the total knee arthroplasty group took the longest time.(P<0.05);The VAS score,the ROM and KSS score before operation in three groups showed no significant difference(P>0.05);The VAS scores of three groups decreased post operation,patellofemoral arthroplasty group and total knee replacement group had the lower VAS score postoperative than the arthroscopic debridement group,there were significant differences in postoperative VAS score between the three groups(P<0.05);The postoperative clinical and functional KSS scores in three groups were significantly improved,patellofemoral arthroplasty group and total knee replacement group had a higher postoperative KSS score compared with the arthroscopic debridement group,there was significant difference between the three groups;Preoperative and postoperative ROM of three groups showed no significant difference(P>0.05).Summary: Patellofemoral arthroplasty is an effective surgical procedure for the treatment of patellofemoral arthritis.The outcome of patellofemoral arthroplasty is close to total knee replacement,and better than arthroscopic debridement,the operation time is shorter and patient recover faster.It is an ideal surgical method to treat isolated patellofemoral arthritis.Part 4 Meta analysis of the prosthesis survival and outcomes of patellofemoral arthroplasty with two different prostheses in the treatment of isolated patellar arthritisObjective: Patellofemoral arthroplasty(PFA)has been an option for patients with symptomatic patellofemoral osteoarthritis for many years.Trochlear components currently available can be divided into two groups: inlay and onlay designs.Many authors pointed out that onlay design is better than inlay design because early inlay designs are associated with higher failure rates.In fact,the inlay design prostheses have required good results because of its improvement.This study is to compare clinical results and prosthesis survival rates after patellofemoral arthroplasty(PFA)using either inlay or onlay trochlear design.Methods: A search was performed using PubMed,Embase and Cochrane systems were searched.49 cohort studies were selected according to inclusion and exclusion criteria.Parameters collected including study authors,year of publication,character of people,survivorship of prosthesis,total number of failures,functional outcomes and so on.Statistical analysis was performed using Stata 10.0 statistics soft.Results: The survival rate of prosthesis in inlay group which included 24 studies is 72~100% at different follow-up intervals.The survival rate of prosthesis in onlay group included 25 studies is 85.4~100% at different follow-up intervals.The survival rate combined of all prosthesis in Inlay group and onlay group were 0.87(0.83~0.91)and 0.94(0.93~0.96)respectively.The KSS score,Oxford knee score(OKS)and VAS score of onlay group were higher than those of Inlay group at different follow-up intervals.Summary: The survival rate of onlay prosthesis is higher than Inlay prosthesis,and onlay prosthesis has a better postoperative functional outcome.Conclusion: Patients with trochlear dysplasia have different posterior femoral condyles compared with those without trochlear dysplasia.Patients with this condition have bigger medial posterior condyles and smaller lateral posterior condyles.The animal model found that the dislocation of the patella could lead to dysplasia of the trochlear and femoral condyle,which could result in the degeneration of the knee joint.Patellofemoral arthroplasty is an effective surgical procedure for the treatment of patellofemoral arthritis.The outcome of patellofemoral arthroplasty is close to total knee replacement,and better than arthroscopic debridement.The survival rate of onlay prosthesis is higher than Inlay prosthesis,and onlay prosthesis has a better postoperative functional outcome.