The "ball-in-socket" design of the Medial-Pivot knee system (MicroPort Orthopedics, Arling-ton, Tennessee, USA) aims to reproduce normal knee kinematics by medializing its rotational axis. Thegoal of this study was to measure knee range of motion (ROM) with this implant after a mean follow-up of 10 years and to report the survivorship and long-term clinical and radiological outcomes. Wehypothesized the prosthetic knee would have at least 120◦flexion at 10 years. This was retrospective, single-centre study of 74 Medial-Pivot knees implanted in71 patients (average age of 69 years) between May 2005 and November 2007. All patients who receiveda Medial-Pivot knee were included consecutively. The mean follow-up was 10 years. Clinical and radio-logical assessments were performed using the Knee Society Score (KSS) and Ewald's score. Kaplan-Meirsurvival analysis was used to calculate survivorship.

methodsThis was retrospective, single-centre study of 74 Medial-Pivotknees implanted in 71 patients between May 2005 and Novem-ber 2007. During this period, several types of semi-constrainedprimary TKA implants were used.The "ball-in-socket" design of the Medial-Pivot knee system (MicroPort Orthopedics, Arling-ton, Tennessee, USA) aims to reproduce normal knee kinematics by medializing its rotational axis. Thegoal of this study was to measure knee range of motion (ROM) with this implant after a mean follow-up of 10 years and to report the survivorship and long-term clinical and radiological outcomes. Wehypothesized the prosthetic knee would have at least 120◦flexion at 10 years. This was retrospective, single-centre study of 74 Medial-Pivot knees implanted in71 patients (average age of 69 years) between May 2005 and November 2007. All patients who receiveda Medial-Pivot knee were included consecutively. The mean follow-up was 10 years. Clinical and radio-logical assessments were performed using the Knee Society Score (KSS) and Ewald's score. Kaplan-Meirsurvival analysis was used to calculate survivorship.

Inclusion Criteria:

• patients > 18 years
• patienst must be operated
• patient with mid-line skin incision

Exclusion Criteria:

• patients < 18 years

The patients were operated by four experienced surgeons usingthe same protocol. A mid-line skin incision was made in all patientsexcept one who had previously undergone a lateral osteotomy. The parapatellar arthrotomy was medial in all cases. Independent tibialand femoral cuts were made with an intramedullary femoral aim-ing device targeting 7◦valgus in 48 cases and 5◦in 2 cases. Femoral component external rotation of 3◦relative to the posterior condy-lar plane was applied in all patients. All implants were fixed usingPalacos®bone cement with gentamicin (Haeraus, Warsaw, USA).The patella was resurfaced in 40 knees.