The sacroiliac joint – Victim or culprit

Biomechanical, biochemical, and histological characterization of sacroiliac joint cartilage in the Yucatan minipig

Although the sacroiliac (SI) joint can be a source of lower back and buttock pain, no comprehensive characterization studies on SI cartilage have been conducted. Using the minipig as a large animal model, this study conducted the first biomechanical, biochemical, and histological characterization of SI joint cartilage. Because previous literature has reported that sacral cartilage and iliac cartilage within the SI joint are histologically distinct, concomitantly it was expected that functional properties of the sacral cartilage would differ from those of the iliac cartilage. Creep indentation, uniaxial tension, biochemical, and histological analyses were conducted on the sacral and iliac cartilage of skeletally mature female Yucatan minipigs (n = 6-8 for all quantitative tests). Concurring with prior literature, the iliac cartilage appeared to be more fibrous than the sacral cartilage. Glycosaminoglycan content was 2.2 times higher in the sacral cartilage. The aggregate modulus of the sacral cartilage was 133 ± 62 kPa, significantly higher than iliac cartilage, which only had an aggregate modulus of 51 ± 61 kPa. Tensile testing was conducted in both cranial-caudal and ventral-dorsal axes, and Young's modulus values ranged from 2.5 ± 1.5 MPa to 13.6 ± 1.5 MPa, depending on anatomical structure (i.e., sacral vs. iliac) and orientation of the tensile test. The Young's modulus of sacral cartilage was 5.5 times higher in the cranial-caudal axis and 2.0 times higher in the ventral-dorsal axis than the iliac cartilage. The results indicate that the sacral and iliac cartilages are functionally distinct from each other. Understanding the distinct differences between sacral and iliac cartilage provides insight into the structure and function of the SI joint, which may inform future research aimed at repairing SI joint cartilage.

Influence of size and shape of the auricular surfaces on subchondral bone density distribution in the sacroiliac joint

The sacroiliac auricular surface has a variable morphology and size. The impact of such variations on subchondral mineralization distribution has not been investigated. Sixty-nine datasets were subjected to CT-osteoabsorptiometry for the qualitative visualization of chronic loading conditions of the subchondral bone plate using color-mapped densitograms based on Hounsfield Units in CT. Auricular surface morphologies were classified into three types based on posterior angle size: Type 1: >160°, Type 2: 130-160° and Type 3: <130°. Auricular surface size was categorized based on the mean value (15.4 cm2 ) separating the group into 'small' and 'large' joint surfaces. Subchondral bone density patterns were qualitatively classified into four color patterns: two marginal patterns (M1 and M2) and two non-marginal patterns (N1 and N2) and each iliac and sacral surface was subsequently categorized. 'Marginal' meant that 60-70% of the surface was less mineralized compared with the highly dense regions and vice versa for the 'non-marginal' patterns. M1 had anterior border mineralization and M2 had mineralization scattered around the borders. N1 had mineralization spread over the whole superior region, N2 had mineralization spread over the superior and anterior regions. Auricular surface area averaged 15.4 ± 3.6 cm2 , with a tendency for males to have larger joint surfaces. Type 2 was the most common (75%) and type 3 the least common morphology (9%). M1 was the most common pattern (62% of surfaces) by sex (males 60%, females 64%) with the anterior border as the densest region in all three morphologies. Sacra have a majority of surfaces with patterns from the marginal group (98%). Ilia have mineralization concentrated at the anterior border (patterns M1 and N2 combined: 83%). Load distribution differences related to auricular surface morphology seems to have little effect on long-term stress-related bone adaptation visualized with CT-osteoabsorptiometry. Higher iliac side mineralization was observed in larger joint surfaces and age-related morphomechanical size alterations were seen in males.

Auricular surface morphology and surface area does not influence subchondral bone density distribution in the dysfunctional sacroiliac joint

The subchondral lamella of the sacroiliac auricular surface is morphologically inconsistent. Its morpho-mechanical relationship with dysfunction (SIJD) remains unstudied. Here, the iliac and sacral subchondral bone mineralization is compared between morphological subtypes and in large and small surfaces, in SIJD joints and controls. CT datasets from 29 patients with bilateral or unilateral SIJD were subjected to CT-osteoabsorptiometry. Surface areas and posterior angles were calculated and surfaces were classified by size: small (<15 cm³ ) and large (≥15 cm³ ), and morphological types: 1 (>160°), 2 (130°-160°), and 3 (<130°). Mineralization patterns were identified: two marginal (M1 and M2) and two non-marginal (N1 and N2). Each sacral and iliac surface was subsequently classified. Dysfunctional cohort area averaged 15.0 ± 2.4 cm² (males 16.2 ± 2.5 cm² , females 13.7 ± 1.6 cm² ). No age correlations with surface area were found nor mean Hounsfield Unit differences when comparing sizes, sexes or morphology-type. Controls and dysfunctional cohort comparison revealed differences in female sacra (p = 0.02) and small sacra (p = 0.03). There was low-conformity in marginal and non-marginal patterns, 26% for contralateral non-dysfunctional joints, and 46% for dysfunctional joints. The majority of painful joints was of type 2 morphology (59%), equally distributed between small (49%) and large joints (51%). Larger joints had the highest frequency of dysfunctional joints (72%). Auricular surface morphology seems to have little impact on pain-related subchondral lamella adaptation in SIJD. Larger joints may be predisposed to the onset of pain due to the weakening of the extracapsular structures. Dysfunctional joints reflect common conformity patterns of sacral-apex mineralization with corresponding superior corner iliac mineralization.

Coexistence of Biopsychosocial Factors With Lumbopelvic Pain in Indian Women: A Systematic Review

In general, women appear to report lumbopelvic pain (LPP) more frequently. In addition to the biomechanical risks, this systematic review aimed to identify the add-on biopsychosocial implications of LPP among women in the Indian community. PubMed, ScienceDirect, Web of Science, PEDro, and Google Scholar were searched twice from inception to a final systematic literature search in December 2022. All studies addressing Indian women with LPP were selected. Studies on non-musculoskeletal LPP were excluded. Qualities of non-experimental and experimental research articles were assessed through the Critical Appraisal Skills Programme (CASP) checklist and Cochrane risk of bias criteria for Effective Practice and Organization of Care reviewsrespectively. Data synthesis was narrative as the selected studies differed substantially. Habitual squatting, kneeling, and continuous sitting were identified as ergonomic risks to LPP. Menopause, cesarean, and multiple deliveries influence the onset of LPP among women. There is a severe deficit in data about the musculoskeletal implications of LPP. There are insufficient data present to summarize the biopsychosocial risks of LPP. Even the exact anatomical sites of LPP were not described in most articles. Due to the severe scarcity of data, there is an alarming need to explore the musculoskeletal as well as psychosocial consequences of LPP in Indian women. Among rural women, LPP was common in those working as laborers; which are physically robust jobs with respect to strength and anthropometrics of women. Domestic chores in India involve a lot of manual work; placing unequal loads on the lumbar spine, eventually resulting in LPP. Therefore ergonomic strategies for women should be designed to meet the needs and demands of their respective occupations as well as domestic chores.

Pain and functional outcomes of the sacroiliac joint after platelet-rich plasma injection: a descriptive review

The purpose of this manuscript is to highlight and review the status of literature regarding efficacy of platelet-rich plasma (PRP) in the treatment of sacroiliac joint (SIJ) dysfunction. A review of the literature on PRP interventions on the SIJ or ligaments was performed. Seven studies had improvements in their respective primary end point and demonstrated a strong safety profile without any serious adverse events. Only five articles demonstrated clinical efficacy of >50% in their primary outcome measures. There appears to be inconsistent and insufficient evidence for a conclusive recommendation for or against SIJ PRP. There is a need for adequately powered well-designed, standardized, double-blinded randomized clinical trials to determine the effectiveness of PRP in SIJ-mediated pain.