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Original Article

Improved Early Clinical Outcomes of RP/PS Mobile-Bearing Total Knee Arthroplasties

Tae Kyun Kim^{1, 2}, Hyung Joon Cho¹, Yeon Gwi Kang¹, Sung Ju Kim³ and Chong Bum Chang^{1, 2}

(1)	Joint Reconstruction Center, Seoul National University Bundang Hospital, 300 Gumidong, Bundangu, Seongnam-si, Gyunggido, 463-707, Korea

(2)	The Department of Orthopaedic Surgery, Seoul National University College of Medicine, Seoul, Korea

(3)	Department of Statistics, Korea University, Seoul, Korea

Received: 16 September 2008 Accepted: 3 March 2009 Published online: 19 March 2009

Abstract The rotating-platform posterior-stabilized (RP/PS) prosthesis was developed to take advantage of the benefits of the traditional RP mobile-bearing system and the posterior-stabilized design. This nonconsecutive cohort study compared the clinical outcomes of TKAs performed using a RP/PS mobile system or a floating-platform (FP) system. The clinical outcomes of 93 TKAs with a RP/PS prosthesis were compared with the same number of TKAs with a FP mobile-bearing prosthesis at 6, 12, and 24 months after surgery. Clinical outcomes differed between the FP and RP/PS groups as a function of length of followup. In the FP group, most outcomes peaked at 12 months and then deteriorated, whereas in the RP/PS group, outcomes stabilized or continued to improve between 12 and 24 months. The RP/PS group had greater maximum flexion throughout followup and better clinical outcomes 24 months after surgery. Patient satisfaction was superior in the RP/RS group. This study suggests the RP/PS prosthesis provides better functional outcomes, including greater maximum flexion and better patient satisfaction. We propose the RP/PS mobile-bearing system is a more attractive option than the FP mobile-bearing system for patient populations of elderly women similar to patients enrolled in our study.

Level of Evidence: Level III, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

One or more of the authors (TKK) have received funding from the clinical research fund (B-0605/033-032) of Seoul National University Bundang Hospital.

Each author certifies that his or her institution has approved the human protocol for this investigation, that all investigations were conducted in conformity with ethical principles of research, and that informed consent was obtained.

This work was performed at Seoul National University Bundang Hospital.

Tae Kyun Kim
Email: osktk@snubh.org

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