Arthroscopy - 2026-09-09 - Journal Article
Coronal Alignment Changes in the Patellofemoral Joint Are Smaller Than Correction Angle and Have Little Impact on Clinical Scores and Cartilage Damage After Medial Open-Wedge High Tibial Osteotomy.
Maeda T, Kuriyama S, Sakai S, Morita Y, Morita Y, Nishitani K, Nakamura S, Matsuda S
Topics
Key Takeaway
After medial open-wedge HTO with a mean coronal correction of 9.3°, patellofemoral coronal alignment changes were substantially smaller (patellar ridge 3.0°, quadriceps femoris 6.8°) and did not meaningfully correlate with KOOS subscales or ICRS cartilage grade changes.
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Summary
This retrospective case series examined whether coronal correction angle during medial open-wedge HTO drives patellofemoral joint (PFJ) alignment changes and affects KOOS outcomes or ICRS cartilage grades. CT-based coronal PFJ angles were measured pre- and postoperatively in 45 knees undergoing HTO between 2019 and 2022. PFJ alignment changes were significantly smaller than the 9.3° mean correction angle, patellar cartilage ICRS grade worsened slightly (P=.004), and only patellar tendon angle correlated weakly with KOOS ADL decline (r=-0.333), with no other clinically meaningful correlations identified.
Key Limitation
The retrospective design with only 45 knees and no standardized follow-up interval between HTO and second-look arthroscopy prevents determination of whether observed patellar cartilage ICRS grade worsening is procedure-related or disease progression.
Original Abstract
PURPOSE
To investigate the impact of the correction angle on changes in patellofemoral joint (PFJ) alignment in the coronal plane before and after medial open-wedge high tibial osteotomy and its effect on postoperative patient-reported outcome measures and PFJ cartilage damage.
METHODS
Patients who underwent medial open-wedge high tibial osteotomy between 2019 and 2022 and had pre- and postoperative whole-leg computed tomography were included. Coronal PFJ alignment was investigated using angles of the patellar ridge, femoral trochlear groove, quadriceps femoris, and patellar tendon. All coronal angular measurements were formed along the x-axis. Knee Injury and Osteoarthritis Outcome Score obtained preoperatively and before implant removal and International Cartilage Repair Society grades of the PFJ based on primary and second-look arthroscopic findings were evaluated. The minimal clinically important difference was defined as half the standard deviation of the score changes.
RESULTS
Forty-five knees of 39 patients were analyzed. Mean coronal correction angle on postoperative computed tomography was 9.3°. Changes in PFJ alignment indicators were significantly smaller than the correction angle, with the patellar ridge being less affected than the quadriceps femoris (3.0° vs 6.8°, P < .001). Only the Knee Injury and Osteoarthritis Outcome Score for activities of daily living decreased as the patellar tendon angle increased (r = -0.333). More than 70% of patients achieved an improvement greater than the minimal clinically important difference for the Knee Injury and Osteoarthritis Outcome Score subscales. The difference in the pre- and postoperative International Cartilage Repair Society grades of the patellar cartilage worsened slightly (P = .004). No significant correlations were found between changes in the International Cartilage Repair Society grade and any clinical scores before and after medial open-wedge high tibial osteotomy.
CONCLUSIONS
Changes in PFJ alignment indicators were significantly smaller than those in the coronal correction angle, particularly for bony indicators. The correlations between clinical scores or PFJ cartilage damage and changes in PFJ alignment indicators were negligible in the coronal plane.
LEVEL OF EVIDENCE
Level IV, retrospective case series.