Does Periacetabular Osteotomy Have Depth-related Effects on the Articular Cartilage of the Hip?

Abstract

Background Osteoarthritis may result from abnormal mechanics leading to biochemically mediated degradation of cartilage. In a dysplastic hip, the periacetabular osteotomy (PAO) is designed to normalize the mechanics and our initial analysis suggests that it may also alter the cartilage biochemical composition. Articular cartilage structure and biology vary with the depth from the articular surface including the concentration of glycosaminoglycans (GAG), which are the charge macromolecules that are rapidly turned over and are lost in early osteoarthritis. Delayed gadolinium-enhanced magnetic resonance imaging of cartilage (dGEMRIC) enables noninvasive measurement of cartilage GAG content. The dGEMRIC index represents an indirect measure of GAG concentration with lower values indicating less GAG content. GAG content can normally vary with mechanical loading; however, progressive loss of GAG is associated with osteoarthritis. By looking at the changes in amounts of GAG in response to a PAO at different depths of cartilage, we may gain further insights into the types of biologic events that are occurring in the joint after a PAO. Questions/purposes We (1) measured the GAG content in the superficial and deep zones for the entire joint before and after PAO; and (2) investigated if the changes in the superficial and deep zone GAG content after PAO varied with different locations within the joint. Methods This prospective study included 37 hips in 37 patients (mean age 26 ± 9 years) who were treated with periacetabular osteotomy for symptomatic acetabular dysplasia and had preoperative and 1-year follow up dGEMRIC scans. Twenty-eight of the 37 also had 2-year scans. Patients were eligible if they had symptomatic acetabular dysplasia with lateral center-edge angle \ 20°a nd no or minimal osteoarthritis. The change in dGEMRIC after surgery was assessed in the superficial and deep cartilage zones at five acetabular radial planes. Results The mean ± SD dGEMRIC index in the superficial zone fell from 480 ± 137 msec preoperatively to 409 ± 119 msec at Year 1 (95% confidence interval [CI], À87 to À54; p \0.001) and recovered to 451 ± 115 msec at Year 2 (95% CI, 34-65; p \ 0.001), suggesting that there is a transient event that causes the biologically sensitive superficial layer to lose GAG. In the deep acetabular cartilage zone, dGEMRIC index fell from 527 ± 148 msec preoperatively to 468 ± 143 msec at Year 1 (95% CI, À66 to À30; p\0.001) and recovered to 494 ± 125 msec at Year 2 (95% CI, 5-32; p = 0.008). When each acetabular radial plane was looked at separately, the change from before surgery to 1 year after was confined to zones around the superior part of the joint.

Automatic MRI-based Three-dimensional Models of Hip Cartilage Provide Improved Morphologic and Biochemical Analysis

“…By contrast, the use of biochemical MRI sequences such as delayed gadolinium-enhanced MRI of cartilage (dGEMRIC) [12], T2 [21], T2* [8], or T1rho [4] are sensitive to early degenerative changes in cartilage composition. Among these techniques, dGEMRIC is perhaps the one used most commonly in the hip [11,12,23,24,26,43,44]. dGEMRIC is based on the depletion of negatively-charged glycosaminoglycan molecules that are replaced by the negatively charged gadolinium.…”

Periacetabular osteotomy with or without arthroscopic management in patients with hip dysplasia: study protocol for a multicenter randomized controlled trial

“…Furthermore, no study to date has assessed the impact of concomitant arthroscopy with labral treatment and PAO on cartilage health. There have been several studies using advanced magnetic resonance imaging (MRI) for cartilage before and after PAO, showing its effect on the cartilage matrix [33], but none yet with the adjunct of hip arthroscopy. Hence, it is imperative to determine how the addition of labral repair/debridement may affect the hip cartilage health/status.…”

“…Furthermore, it is unknown whether cartilage damage can be mitigated with the addition of an arthroscopic procedure [33]. Due to additional operative time, equipment, and human resources, costs are substantially increased by adding an arthroscopy to a PAO [34,35].…”

“…Although hip arthroscopy allows the surgeon to potentially address other intraarticular pathologies (i.e., ligamentum teres, chondral injuries), the effect of arthroscopic management of these injuries concomitantly with PAO is unknown. Furthermore, it is unknown whether cartilage damage can be mitigated with the addition of an arthroscopic procedure [ 33 ]. Due to additional operative time, equipment, and human resources, costs are substantially increased by adding an arthroscopy to a PAO [ 34 , 35 ].…”

Early-term hip development following Pemberton osteotomy: a radiological follow-up

“…Asetabulum remodelizasyonu sonucu sığ olan asetabulumun geliş-mesi ile kalça ekleminde, femur başı ve asetabulum üzerindeki kontakt basıncın azaldığı ve kıkırdak yapı-nın biyokimyasal özelliklerinin de değiştiği gösteril-miştir. [10][11][12] Asetabulum gelişimi üzerine yapılan birçok çalışmada, Aİ, asetabüler Sharp açısı, asetabulum derinlik gibi radyolojik parametreler göz önün-de bulundurularak asetabüler gelişimin takip süresiyle ilişkisi değerlendirilmiştir. Schwartz [13] ve Salter [14] kapalı redüksiyon sonrası Aİ gelişimi-nin ilk 18 ayda en fazla olduğunu belirtmişlerdir.…”