The Short-term Efficacy Of Unicompartmental Knee Aarthroplasty In Treatment Of Medial Compartment Arthritis

Objectives:Unicompartmental knee arthroplasty (UKA) in treatment of isolatedcompartment arthritis has been widely used at present. In this paper, we aim to evaluateshort-term efficacyofunicompartmental knee arthroplasty with Oxford phase-3unicompartmental knee prosthesis in treatment of isolated medial compartment arthritis.Methods：The study was carried out on retrospective case-control methods. Thesurgical indications of the Oxford unicompartmental knee arthroplasty for17consecutive patients who underwent UKA for isolated medial knee osteoarthritis thathad been unresponsive to conservative treatment.Including3males (knee) and14females (14knees),7cases of the left knee, right knee in10cases, the average age ofsurgery was64years (52-81years old), the average weight of68Kg (54-82Kg). Alloperations were performed by the same surgeon withminimally invasive surgery and theOxford phase-3mobile-bearing unicompartmental knee prosthesis. The anteroposteriorand lateral X-ray ofknee joint and the full-length standing radiograph of the lowerextremitieswere takenin order to observe osteoarthritis of the knee and limb alignmentpreoperativelyand to observe prosthesis position, matching condition and limbalignmentpostoperatively． We use statistical methods (P <0.05was consideredstatistically significant) and SPSS17.0software for processing the experimentaldata.The results were assessed preoperatively and final follow-up according to HSS(Hospital for Special Surgery knee score),KSS（Knee clinical and functional SocietyScores）, range of motion, hip-knee-ankle angle.We observed the patients all the timeand took some activities to prevent complications postoperatively.Results：All patients were maintained follow-up, none of the patients lost tofollow-up.The operation time was96.7（70-130）min.None of patients need bloodtransfusion in theperioperative period.All the incisions were primary healing afteroperation.The average hospitalization days were10days (7-14days).The mean follow-up period was8months (range5to14months). At the time of the finalfollow-up, all patients with pain symptoms were relieved.Complications such asinfection, pulmonary embolism, deep venous thrombosis, iatrogenic neurovascularinjury, or prosthesis loosening, insert dislocation were not observed, the quality ofliving were improved in all patients. The mean preoperative and final follow-up HSSwere65.1and90.1, the mean knee clinical scores were64.6and95.7, and the meanfunctional scores were57.6and89.4. Preoperative and final follow-up, the differenceswere statistically significant (P <0.05). The HSS of were excellent in15patients(88.2％), good in2patients（11.8％）.All the patients had an excellent kneeclinical score, while functional scores were excellent in14patients (82.4%) and good in3patients (17.6%).There was no limitation in knee extension at final follow-up. Themean preoperative range of motion of knee increased from115.6°to129.4°at finalfollow-up (p<0.05).Postoperative radiographic measurements showed that themechanical axis was within acceptable ranges in all the patients with a mean of1.2°varus. The difference was statistically significant in the final preoperativeand finalfollow-up(p<0.05).Conclusion：The findings show that, with reasonable indications selection ofsurgery, continuously improve surgical technique and the Oxford phase-3mobile-bearing unicompartmental knee prosthesis, unicompartmental knee arthroplastythat using minimally invasive surgery in treatment of isolated medial compartmentarthritis has less trauma,shorter operative time, less bone cutting,less blood loss atintra-operation and a larger range of motion, shorter hospital stay,fewer complications,faster functional recovery, less cost and other advantages, achieved excellent or goodshort-term clinical efficacy. And the long-term efficacy of this therapy still needsobservation.