Ten- to 14-Year Results of a High-Flex Rotating Platform Knee Implant: A Follow-Up Report of a Prospective Cohort

• Published in: Indian journal of orthopaedics Vol. 56; no. 2; pp. 256 - 262
• Main Authors: Maniar, Adit R., Gajjar, Arpit, Bhatnagar, Nishit, Mishra, Abhinav, Maniar, Rajesh N.
• Format: Journal Article
• Language: English
• Published: New Delhi Springer India 01.02.2022
• Subjects: Conservative Orthopedics; Medicine; Medicine & Public Health; Original; Original Article; Orthopedics; Surgical Orthopedics; High flex; Ten-year results; Posterior stabilised; Knee arthroplasty; Rotating platform; Outcomes
• ISSN: 0019-5413; 1998-3727
• DOI: 10.1007/s43465-021-00441-2

Background High-flex posterior stabilised rotating platform (PSRP) implant was introduced to provide for deep knee flexion. Few short-term results have been reported, but there are no long-term outcomes reported. Methods We prospectively followed 48 patients (53 knees) implanted with one such design. Inclusion criteria for implantation were patients with good pre-operative flexion and wishing to perform activities requiring deep knee flexion post-operatively, with femorotibial varus angle < 15° and having good flexion stability at trialling stage. Previously, we reported their outcomes at 2–6 years (FU-1). We now report their functional and radiological results at a minimum follow-up of 10 years (FU-2) in 39 patients (43 knees); 5 patients having died and 4 lost to follow-up. Results The mean pre-operative flexion of 124° improved to 130° at FU-1 and to 134° at FU-2. Flexion of 130° or more was seen in 59.6% knees at FU-1 and 74.42% knees at FU-2. At FU-2 mean Knee score was 90.5 and Function score was 67.8. Incidence of patellofemoral symptoms increased from 7.7% at FU-1 to 11.36% at FU-2. There were no cases of bearing spin out, osteolysis or revision surgeries. Conclusion At a minimum 10-year follow-up, high-flexion PSRP design in selected patients yielded 100% survival. We recorded good knee flexion and knee society scores, with no case of spin out, implant loosening, osteolysis or revision surgery. Although deep knee flexion improved at longer follow-up, its use in ADL had reduced due to other age-related factors. There was increased incidence of patellofemoral symptoms.