Multi-centre randomised controlled trial comparing arthroscopic hip surgery to physiotherapist-led care for femoroacetabular impingement (FAI) syndrome on hip cartilage metabolism: the Australian FASHIoN trial

Background Arthroscopic surgery for femoroacetabular impingement syndrome (FAI) is known to lead to self-reported symptom improvement. In the context of surgical interventions with known contextual effects and no true sham comparator trials, it is important to ascertain outcomes that are less susceptible to placebo effects. The primary aim of this trial was to determine if study participants with FAI who have hip arthroscopy demonstrate greater improvements in delayed gadolinium-enhanced magnetic resonance imaging (MRI) of cartilage (dGEMRIC) index between baseline and 12 months, compared to participants who undergo physiotherapist-led management. Methods Multi-centre, pragmatic, two-arm superiority randomised controlled trial comparing physiotherapist-led management to hip arthroscopy for FAI. FAI participants were recruited from participating orthopaedic surgeons clinics, and randomly allocated to receive either physiotherapist-led conservative care or surgery. The surgical intervention was arthroscopic FAI surgery. The physiotherapist-led conservative management was an individualised physiotherapy program, named Personalised Hip Therapy (PHT). The primary outcome measure was change in dGEMRIC score between baseline and 12 months. Secondary outcomes included a range of patient-reported outcomes and structural measures relevant to FAI pathoanatomy and hip osteoarthritis development. Interventions were compared by intention-to-treat analysis. Results Ninety-nine participants were recruited, of mean age 33 years and 58% male. Primary outcome data were available for 53 participants (27 in surgical group, 26 in PHT). The adjusted group difference in change at 12 months in dGEMRIC was -59 ms (95%CI − 137.9 to - 19.6) (p = 0.14) favouring PHT. Hip-related quality of life (iHOT-33) showed improvements in both groups with the adjusted between-group difference at 12 months showing a statistically and clinically important improvement in arthroscopy of 14 units (95% CI 5.6 to 23.9) (p = 0.003). Conclusion The primary outcome of dGEMRIC showed no statistically significant difference between PHT and arthroscopic hip surgery at 12 months of follow-up. Patients treated with surgery reported greater benefits in symptoms at 12 months compared to PHT, but these benefits are not explained by better hip cartilage metabolism. Trial registration details Australia New Zealand Clinical Trials Registry reference: ACTRN12615001177549. Trial registered 2/11/2015.

The Mechanoadaptation Concept of Cells

Almost all cells in the human body are subjected to mechanical stresses. These forces can vary from a few Pascals (shear stress) to some mega Pascals (on hip cartilage). It is now well known that mechanical forces have a decisive effect on cellular physiology. In 1880, W. Roux introduced the concept of functional adaptation; which can be defined as a quantitative autoregulation controlled by stimuli like mechanical forces. These stresses influence functionality and cellular metabolism and can lead to appropriate tissue remodelling by triggering a cascade of reactions (mechanotransduction), being the signal for the adaptation of cells and tissues. However, although the main biological effects of mechanical forces are well documented, the relation between mechanical forces and physiological phenomena is largely unknown. In this paper, some effects of mechanical stresses on different cells (mesenchymal stem cells, bone cells, chondrocyte, endothelial cells, vascular or muscular cells, etc.) are summarized.

Feasibility of ultrashort echo time (UTE) T2* cartilage mapping in the hip: a pilot study

Background Ultrashort echo time (UTE) T2* is sensitive to molecular changes within the deep calcified layer of cartilage. Feasibility of its use in the hip needs to be established to determine suitability for clinical use. Purpose To establish feasibility of UTE T2* cartilage mapping in the hip and determine if differences in regional values exist. Material and Methods MRI scans with UTE T2* cartilage maps were prospectively acquired on eight hips. Hip cartilage was segmented into whole and deep layers in anterosuperior, superior, and posterosuperior regions. Quantitative UTE T2* maps were analyzed (independent one-way ANOVA) and reliability was calculated (ICC). Results UTE T2* mean values (anterosuperior, superior, posterosuperior): full femoral layer (19.55, 18.43, 16.84 ms) ( P=0.004), full acetabular layer (19.37, 17.50, 16.73 ms) ( P=0.013), deep femoral layer (18.68, 17.90, 15.74 ms) ( P=0.010), and deep acetabular layer (17.81, 16.18, 15.31 ms) ( P=0.007). Values were higher in anterosuperior compared to posterosuperior regions (mean difference; 95% confidence interval [CI]): full femur layer (2.71 ms; 95% CI 0.91–4.51: P=0.003), deep femur layer (2.94 ms; 95% CI 0.69–5.19; P=0.009), full acetabular layer (2.63 ms 95% CI 0.55–4.72; P=0.012), and deep acetabular layer (2.50 ms; 95% CI 0.69–4.30; P=0.006). Intra-reader (ICC 0.89–0.99) and inter-reader reliability (ICC 0.63–0.96) were good to excellent for the majority of cartilage layers. Conclusion UTE T2* cartilage mapping was feasible in the hip with mean values in the range of 16.84–19.55 ms in the femur and 16.73–19.37 ms in the acetabulum. Significantly higher values were present in the anterosuperior region compared to the posterosuperior region.