Impact of patellar height on unicompartment knee arthroplasty: Does patella baja lead to an inferior outcome?

Devdatta Suhas Neogi, Ji Hoon Bae, Chang Woo Seok, Hong Chul Lim

Research output: Contribution to journalArticlepeer-review

9 Citations (Scopus)


Background: Though a number of series with long-term results have been published, there is still a paucity of literature on the role of patellar height after unicompartment knee arthroplasty (UKA). The present study was conducted with a hypothesis that patella baja may lead to a poor outcome at follow-up. Materials and methods: A retrospective review of 134 knees was performed and patellar height calculated before and after UKA by Blackburne-Peel index (BPI) and the Insall-Salvati ratio (ISR) on true lateral radiographs of the patients in 30° of flexion taken pre-operatively and at 1 year, 2 years and final follow-up (minimum 5 years). Statistical analysis was performed to evaluate the outcomes. Results: There was a decrease in ISR in 14.18 % and in BPI in 19.4 % at final follow-up. There was a significant decrease in BPI values while the decrease was not significant for ISR. After eliminating the pre-operative patella baja, 7.3 % developed post-operative patella baja, according to ISR, while 11.5 % developed patella baja as per BPI. At final follow-up there was a statistically significant decrease in stair climbing scores in patients with patella baja when compared to patients with normal ISR. Conclusion: Patients with a decrease in patellar height as per ISR have a decrease in stair climbing score at mid-term follow-up while the overall KSS, and pain scores are not affected by a change in patellar height and neither is there a significant progress in patellofemoral osteoarthritis among patients with patella baja compared to normal patella.

Original languageEnglish
Pages (from-to)47-54
Number of pages8
JournalJournal of Orthopaedics and Traumatology
Issue number1
Publication statusPublished - 2014 Mar
Externally publishedYes


  • Blackburne-Peel Index
  • Insall-Salvati ratio
  • Patella baja
  • Patellar height
  • UKA
  • Unicompartmental arthroplasty

ASJC Scopus subject areas

  • Surgery
  • Orthopedics and Sports Medicine


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