Patellofemoral Arthroplasty Improves Patellofemoral Alignment In Pfoa Patients With Trochlear Dysplasia

Objective: The impact of trochlear dysplasia on patellofemoral arthroplasty(PFA)was rarely reported in the current literature.The purpose of the study was to explore the effectiveness of PFA on correcting the patellofemoral alignment in the patellofemoral osteoarthritis(PFOA)patients with dysplastic trochlea.Methods: From January 2014 to March 2018,thirty-five PFOA patients(female: 29,male: 6)with trochlear dysplasia underwent PFA were included in the study.Representative measurements on the patellar congruence included patellar tilt,congruence angle,Blackburne-peel index was measured preoperatively and postoperatively.The tibia tuberosity-trochlear groove(TTTG)distance,lateral trochlear inclination was measured preoperatively and postoperatively to explore the changes in patellofemoral alignment.Results: The mean follow-up time was 24 months(range from 18 to 42months).The interrater and inter-observer reliability was excellent in all measurements preoperatively and postoperatively.The patellar tilt decreased from 23.3°±6.3° preoperatively to 6.4°±2.3° postoperatively(P <0.001).The congruence angle decreased from 32.3°±8.6° preoperatively to 10.2°±3.6° postoperatively(P <0.001).The lateral trochlear inclination increased from 8.3°±4.1° preoperatively to 16.0°±1.2° postoperatively(P <0.001).The TT-TG distance decreased from 18.2±3.8mm preoperatively to 11.5±3.3mm postoperatively(P <0.001).No significant difference was found in the Blackburne-Peel ratio(P =0.390).The average score of OKS in the follow-up was significantly improved compared with the preoperative,improving from 19.5 to 29.2 in the sixth month(P <0.001),37.9 in first one year(P <0.001),39.1 at final follow up(P <0.001).Conclusions: During the short-term follow-up,no patellofemoral malalignment or prosthesis loosening occurred in these patients.Postoperative outcomes of the patellofemoral alignments and knee function got significantly improved.In the PFOA patients with trochlear dysplasia,the patellofemoral arthroplasty could well correct the trochlear dysplasia and related patellofemoral malalignments.