2023 ISAKOS Biennial Congress ePoster
Lowered Patella and Higher Age the Relevant Predictors of Patellofemoral Osteoarthritis after Anterior Cruciate Ligament Reconstruction of the Knee
Takayuki Okumo, MD, PhD, Tokyo, Tokyo JAPAN
Atsushi Sato, MD, PhD, Koto-Ku, Tokyo JAPAN
Masataka Ota, MD, Tokyo JAPAN
Kanako Izukashi, MD, Yokohama, Kanagawa JAPAN
Jun Oike, MD,PhD, Koto, Tokyo JAPAN
Saki Yagura, MD, Kawasakishi Miyamaeku, Kanagawa JAPAN
Naoki Okuma, MD, Yokohama, Kanagawa JAPAN
Takayuki Koya, MD, PhD, Chicago, IL UNITED STATES
Fumiyoshi Kawashima, MD, Tokyo JAPAN
Hiroshi Takagi, MD, PhD, Tokyo JAPAN
Koji Kanzaki, Prof., Yokohama JAPAN
Showa University, School of Medicine, Tokyo, Tokyo, JAPAN
FDA Status Not Applicable
Summary
Predictors or contributors to the patellofemoral osteoarthritis (PFOA) after double bundle anterior cruciate ligament reconstruction (ACLR) were retrospectively investigated. Fifty-four patients were assigned in this study. Single and multiple logistic regression analysis showed that age and decreased I-S ratio were considered as main predictors associated with PFOA.
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Abstract
Background
Anterior cruciate ligament reconstruction (ACLR) is performed on young athletes as well as on older patients to prevent the risk of osteoarthritis of the knee in the future. However, it has been reported that patellofemoral osteoarthritis (PFOA) occurs approximately 40 % of patients 5 years after ACLR, even relevant contributors were still unknown. In this study, we retrospectively investigated the main predictors for PFOA after ACLR.
Methods
Anatomical double bundle ACLR was performed for 54 patients with hamstrings tendon in outside–in technique. All patients didn't have PFOA at primary ACLR, then, 7 patients (13%) had PFOA, grade 2 or more in ICRS score, detected by second-look arthroscopy. These patients were categorized in the PFOA (+) group and the others in the non–PFOA group. Patient characteristics, clinical outcome, and CT images were used to assess the relevance to PFOA. In the CT images, posterior tibial slope angle and Insall–Salvati ratio (I–S ratio) were measured. Patient characteristics, clinical outcomes, and CT image measurements were compared between the PFOA (+) group and non–PFOA groups, and univariable and multivariate logistic regression analysis were performed.
Results
Patients in the PFOA (+) group were significantly older than those in the non–PFOA group. At 1–year after ACLR, the PFOA (+) group had weaker knee extensor strength and lower Lysholm score. The PFOA (+) group had a significantly decreased I–S ratio at second–look surgery than the non–PFOA group. (p = 0.011) The decrease in I–S ratio was greater in the PFOA (+) group. Multivariate logistic regression analysis showed that age and difference in I–S ratio were significant contributors to PFOA after ACLR. The I–S ratio difference, with a cutoff value of -3.5%, was relevant to the development of PFOA. Age was also relevant with a cutoff value of 34 years.
Discussion
Some previous reports show that alternation of the patella alignment and hypomobility of the patella were more detected in the patients with PFOA after ACLR. Recently, it has been noted that diffuse fibrosis of the infrapatellar fat pad may hamper the smooth grinding motion of the patella, causing stiffening and shortening of the patellar tendon, as well as PFOA. Patellar tendons may be shortened when operated with BTB grafts, although some reports indicate that the situation is nearly identical with hamstring tendons. In the present study, patellar height, I–S ratio, was significantly decreased, and this alteration was associated with the development of PFOA. In conclusion, the decrease in the I–S ratio at 1 year follow-up after ACLR was significantly associated with the development of PFOA, in addition to patients’ age.