High tibial osteotomy to neutral alignment improves medial knee articular cartilage composition

Abstract

PurposeThe purpose of this study was to: (1) test the hypothesis that HTO improves articular cartilage composition in the medial compartment without adversely affecting the lateral compartment and patella, and; (2) explore associations between knee alignment and cartilage composition after surgery. Methods3T MRI and standing radiographs were obtained from 34 patients before and 1‐year after HTO. Articular cartilage was segmented from T2 maps. Mechanical axis angle (MAA), posterior tibial slope, and patellar height were measured from radiographs. Changes in T2 and radiographic measures were assessed using paired t tests, and associations were assessed using Pearson correlation coefficients. ResultsThe mean (SD) MAA before and after HTO was − 6.5° (2.4) and 0.6° (3.0), respectively. There was statistically significant shortening [mean (95%CI)] of T2 in the medial femur [− 2.8 ms (− 4.2; − 1.3), p < 0.001] and medial tibia [− 2.2 ms (− 3.3; − 1.0), p < 0.001], without changes in the lateral femur [− 0.5 ms (− 1.6; 0.6), p = 0.3], lateral tibia [0.2 ms (− 0.8; 1.1), p = NS], or patella [0.5 ms (− 1.0; 2.1), p = NS). Associations between radiographic measures and T2 were low. 23% of the increase in lateral femur T2 was explained by postoperative posterior tibial slope (r = 0.48). ConclusionPerforming medial opening wedge HTO without overcorrection improves articular cartilage composition in the medial compartment of the knee without compromising the lateral compartment or the patella. Although further research is required, these results suggest HTO is a disease structure‐modifying treatment for knee OA.

How to achieve an optimal alignment in medial opening wedge high tibial osteotomy?

“…Similarly, Atkinson et al. [ 22 ] reported that valgus alignment is not necessary, based on the finding that correction to near neutral alignment rather than excessive valgus alignment is sufficient to provide regenerative stimulation to the articular cartilage of the medial compartment without damaging the lateral compartment. Although there are inherent limitations in biomechanical studies, the findings of which may differ from the clinical outcomes of actual patients, these results need to be considered.…”

Axial alignment is a critical regulator of knee osteoarthritis

“…In addition, many of the normal osteochondral correlations reflecting the fundamental association of all osteochondral constituents ( 1 ) were restored by unloading, in contrast to neutral and varus OA. Although clinical studies examined the structural consequences of axial realignment separately for the articular cartilage ( 43 ) or subchondral bone ( 44 ), no translational studies were available so far investigating these mechanisms at high detail within the whole osteochondral unit as in the present context. At 1.5 years after clinical HTO, structural indices of the trabeculae of the medial tibial plateau changed ( 44 ), indicating organizational adaptation to the altered load.…”

Knee osteoarthritis and management of the retired athlete: the role of osteotomy

“…In a subsequent study, Atkinson et al studied the effect of MOWHTO on cartilage composition in the medial compartment of the knee, as measured by quantitative magnetic resonance imaging (MRI). 12 Of note, they observed significant improvements in T2 relaxation times in the medial compartment cartilage with no increase in relaxation times in the patellofemoral joint or lateral compartment, indicating that MOWHTO may be a disease modifying and structure improving procedure in the treatment of knee OA. This is not the first study to observe such changes in the medial compartment with MOWHTO, with several other studies also highlighting the potential disease modifying, and hence biological benefits of the procedure along with the improvements in mechanical load distribution.…”