Variables affecting patellar height in patients undergoing primary total knee replacement

International Orthopaedics, vol. 45, pp. 1477–1482

Abstract

BACKGROUND: Alteration of patellar height is commonly encountered in total knee arthroplasty (TKA), and failure to address patella baja can result in suboptimal functional outcomes. It may therefore be prudent to evaluate pre-operative patellar height (PPH) and to seek risk factors for patella baja. METHODS: Two hundred eighty-five patients who underwent TKA were included. Patient's age, gender, body mass index (BMI), and history of prior arthroscopy were recorded. PPH was measured using plateau-patella angle (PPA) as well as the Blackburn-Peel (BP), Caton-Deschamps (CD), and Insall-Salvati (IS) ratios. RESULTS: The average patients' age was 71 years with a mean BMI of 30.45. There were 191 female and 94 male patients. One-fourth of the cases had at least one prior knee arthroscopy. Multivariate linear regression analysis identified gender and BMI as variables significantly affecting the IS ratio (p: < 0.05). Gender also had a significant correlation with PPA. Male patients were likely to have lower PPA (p: < 0.03). Though increasing age had a positive correlation with patellar height, this was not statistically significant. History of prior arthroscopy had no significant effect on any of the four PPH measurements. CONCLUSION: Lower patellar height is significantly correlated to male gender and high BMI. We suggest that obese male patients be screened for pre-operative patella baja. This can help in surgical planning and optimizing results in TKA.

Authors 2

1. Khaled Hamed Salem corresponding Aachen Department of Orthopaedic Surgery

   RWTH Aachen University · Cairo University

   Affiliation as printed

   Department of Orthopaedic Surgery, Faculty of Medicine, Cairo University, Cairo, Egypt. khaled_hamedsalem@hotmail.com

   Department of Orthopaedic Surgery, RWTH University Aachen, Aachen, Germany. khaled_hamedsalem@hotmail.com

   Department of Orthopaedic Surgery, Faculty of Medicine, Cairo University, Cairo, Egypt

2. Miten Rajendra Sheth

   Homi Bhabha Centre for Science Education

   Affiliation as printed

   The Knee Clinic, Mumbai, Maharashtra, India