Physical therapeutic options for residual sacrotuberous ligament pain after treatment of sacroiliac joint dysfunction.

[Purpose] To evaluate the incidence of pain originating from the sacrotuberous ligament after sacroiliac joint treatment, and to determine effective physical therapeutic options for sacrotuberous ligament pain. [Participants and Methods] Among 303 patients with sacroiliac joint dysfunction, 57 patients (20 males, 37 females) with persistent lower-buttock pain after sacroiliac joint injections were included in the study. The incidence of sacrotuberous ligament pain and the physical findings from the first evaluation were investigated by physical therapists. [Results] Diagnostic sacrotuberous ligament injections identified lower-buttock pain originating from the sacrotuberous ligament in 57.9% of the patients (33 out of 57 patients) after treatment of sacroiliac joint dysfunction. Of these, 11 patients experienced relief after sacrotuberous ligament injection alone; the others required physical therapy. Sacrotuberous ligament relaxation alone was effective in eight patients; biceps femoris relaxation was required in eight patients; and gluteus maximus contraction exercise was required in six patients. [Conclusion] After sacroiliac joint treatment, the incidence of residual sacrotuberous ligament pain in the persisting lower-buttock pain was 57.9%. In addition to sacrotuberous ligament relaxation, biceps femoris relaxation was effective in patients who showed both higher differences in the straight leg raising test and biceps femoris tenderness, while gluteus maximus contraction exercises were effective in patients with gluteus maximus weakness.

Criteria for Identifying Technically Difficult Cases when Performing Sacroiliac Intraarticular Injections Based on the Grade of Sacroiliac Arthrogram.

OBJECTIVE: An intraarticular sacroiliac joint (SIJ) injection cannot always be performed successfully. Based on the patterns of the sacroiliac arthrogram, we explored possible indicators of technically difficult and technically easy injections into the SIJ including demographic features and anatomical features evident on preprocedural imaging. DESIGN: Observational study. METHODS: We evaluated 76 patients with painful SIJ (total 108 joints) diagnosed by SIJ injections. The sacroiliac arthrogram was graded as follows: Grade (G) 0 = the margin of the joint was partially outlined; G1 = the margin was completely outlined; G2 = intraarticular space was substantially outlined; and G3 = intraarticular space was fully outlined. Two multivariable ordered logistic regression analyses were performed to test the relationships between gender, age, and Grade, as well as between computed tomography (CT) findings and grade. RESULTS: In men, the totals by Grade were G0 = 8 (joints); G1 = 33; G2 = 3; and G3 = 0. In women, these were G0 = 4; G1 = 28; G2 = 22; and G3 = 10. The Grade was significantly higher in women and was also higher with age (P < 0.05). Regarding morphological features in CT, minor osteophytes increased the odds in favor of better Grades of arthrogram (odds ratio = 3.50). Substantial vacuum phenomena strongly increased the odds of better arthrograms (20.52). CONCLUSIONS: Outlining the SIJ cavity fully is significantly more difficult in male patients of any age than in aged female patients. The presence of minor osteophytes and substantial vacuum phenomena on preprocedure CT scans can be reasonably reassuring to the practitioner that they are unlikely to encounter difficulties during injection.

The association between sacroiliac joint-related pain following lumbar spine surgery and spinopelvic parameters: a prospective multicenter study.

PURPOSE: To prospectively calculate the incidence of postoperative sacroiliac joint-related pain (SIJP) and investigate the association between spinopelvic parameters and postoperative SIJP after lumbar spine surgery. METHODS: We prospectively enrolled consecutive patients who underwent lumbar spine surgery. We defined postoperative SIJP as unilateral buttock pain according to fulfillment of the following criteria within 3 months of the surgery: a sacroiliac joint (SIJ) score higher than 4/9 postoperatively; positive response to analgesic periarticular SIJ injection with fluoroscopy; no other complications related to the surgery. The patients were divided into the SIJP group and non-SIJP group. We compared the background information and analyzed the differences in spinopelvic parameters in both groups. Additionally, receiver-operating characteristic curve analyses were performed to evaluate the cutoff values of spinopelvic parameters. RESULTS: Of the 281 patients enrolled, 265 were included and eight developed postoperative SIJP (3.0%). There were no significant differences in the background information between groups. Preoperative and postoperative radiological evaluations revealed that the pelvic incidence (PI) in the SIJP group was significantly higher than that in the non-SIJP group, and there were no significant differences in lumbar lordosis (LL), pelvic tilt, sacral slope, and PI minus LL. For preoperative PI, the area under the curve, cutoff value, sensitivity, and specificity were 0.73739, 59, 62.5%, and 81.9%, respectively. CONCLUSIONS: The incidence of postoperative SIJP after lumbar spine surgery was 3.0%. Higher PI values were associated with a higher risk of postoperative SIJP. These slides can be retrieved under Electronic Supplementary Material.

Fluoroscopy-Guided Sacroiliac Intraarticular Injection via the Middle Portion of the Joint.

OBJECTIVE: Sacroiliac intraarticular injection is necessary to confirm sacroiliac joint (SIJ) pain and is usually performed via the caudal one-third portion of the joint. However, this is occasionally impossible for anatomical reasons, and the success rate is low in clinical settings. We describe a technique via the middle portion of the joint. DESIGN: Observational study. SUBJECTS: Enrolled were 69 consecutive patients (27 men and 42 women, with an average age of 53 years) in whom the middle portion of 100 joints was targeted. METHOD: With the patient lying prone-oblique with the painful side down, a spinal needle was inserted into the middle portion of the joint. Subsequently, the fluoroscopy tube was angled at a caudal tilt of 25-30° to clearly detect the recess between the ilium and sacrum and the needle depth and direction. When the needle reached the posterior joint line, 2% lidocaine was injected after the contrast medium outlined the joint. RESULTS: The success rate of the injection method was 80% (80/100). Among 80 successful cases, four were previously unsuccessful when the conventional method was used. Intraarticular injection using the new technique was unsuccessful in 20 joints; in three of these cases, the conventional method proved successful, and no techniques were successful in the other 17 cases. CONCLUSION: The injection technique via the middle portion of the joint can overcome some of the difficulties of the conventional injection method and can improve the chances of successful intraarticular injection.

A Diagnostic Scoring System for Sacroiliac Joint Pain Originating from the Posterior Ligament.

Objective: Sacroiliac joint (SIJ) pain originating from the posterior ligament manifests in not only the buttocks but also the groin and lower extremities and thus may be difficult to discern from pain secondary to other lumbar disorders. We aimed to develop a simple clinical diagnostic tool to help physicians distinguish between patients with SIJ pain originating from the posterior ligament and those with lumbar disc herniation (LDH) or lumbar spinal canal stenosis (LSS). Design: Prospective case-control study. Patients and Methods: We evaluated 62 patients with SIJ pain originating from the posterior ligament and 59 patients with LDH and LSS. Pain areas, pain increasing positions, provocation test, and tenderness points were investigated. A scoring system based on multivariate logistic regression equations using the investigated items was developed. Results: Two pain areas (the posterosuperior iliac spine (PSIS) detected by the one-finger test and groin), pain while sitting on a chair, provocation test, and two tenderness points (PSIS and the sacrotuberous ligament) had high odds ratios (range, 25.87­1.40) and were used as factors in the scoring system. An integer score derived from the regression coefficient and clinical experience was assigned to each identified risk factor. The sum of the risk score for each patient ranged from 0­9. This scoring system had a sensitivity of 90.3% and a specificity of 86.4% for a positivity cutoff point of 4. Conclusion: The scoring system can help distinguish between patients with SIJ pain originating from the posterior ligament and those with LDH and LSS.

Referred pain location depends on the affected section of the sacroiliac joint.

PURPOSE: Pain referred from the sacroiliac joint (SIJ) may originate in the joint's posterior ligamentous region. The site of referred pain may depend on which SIJ section is affected. This study aimed to determine the exact origin of pain referred from four SIJ sections. METHODS: The study included 50 patients with SIJ dysfunction, confirmed by more than 70 % pain relief after periarticular injection of local anesthetic into the SIJ. The posterior SIJ was divided into four sections-upper, middle, lower, and other (cranial portion of the ilium outside the SIJ)-designated sections 1, 2, 3, and 0, respectively. We then inserted a needle into the periarticular SIJ under fluoroscopy. After the patient identified the area(s) in which the needle insertion produced referred pain, we injected a mixture of 2 % lidocaine and contrast medium into the corresponding SIJ section. RESULTS: Referred pain from SIJ section 0 was mainly located in the upper buttock along the iliac crest; pain from section 1, around the posterosuperior iliac spine; pain from section 2, in the middle buttock area; pain from section 3, in the lower buttock. In all, 22 (44.0 %) patients complained of groin pain, which was slightly relieved by lidocaine injection into SIJ sections 1 and 0. CONCLUSIONS: Dysfunctional upper sections of the SIJ are associated with pain in the upper buttock and lower sections with pain in the lower buttock. Groin pain might be referred from the upper SIJ sections.

Buckling of the Ligamentum Flavum in Patients with Lumbar Spinal Canal Stenosis.

STUDY DESIGN: Experimental study. OBJECTIVE: We sought to elucidate the association between ligamentum flavum thickening and tissue buckling, and the clinical and imaging factors related to buckling by comparing the ligamentum flavum thickness on MRI images and within the actual tissue. SUMMARY OF BACKGROUND DATA: Ligamentum flavum thickening is a main contributor to lumbar spinal canal stenosis. Buckling of the tissue may contribute to ligamentum flavum thickening along with tissue hypertrophy; however, this association has not been established conclusively. MATERIALS AND METHODS: Ligamentum flavum samples (135 ligament samples) from 70 patients with lumbar spinal canal stenosis were evaluated. The ligamentum flavum thicknesses on magnetic resonance imaging (MRI) and in the tissue samples were compared to assess for the presence of buckling. The ligamentum flavum samples were divided into groups with or without buckling based on the difference between their thicknesses on MRI and in the tissues. The Pearson correlation coefficient test was used to assess the relationships between the LF thicknesses on MRI and in the tissues, MRI-tissue difference and LF thickness in the tissues, and MRI-tissue difference and LF thickness on MRI. Further, differences between the buckling+ and buckling- groups were compared using the unpaired t-test (LF thickness on MRI, LF thickness in the tissues, age, disc angle, and disc height) and χ2 (disc level, disc degeneration, and receival/nonreceival of dialysis) test. RESULTS: The ligamentum flavum thickness on MRI and in the tissues had a positive linear relationship, although the thickness was estimated to be significantly larger on MRI than in the tissues themselves. The ligamentum flavum with buckling had a larger thickness on MRI, less tissue hypertrophy, more severe disc degeneration, and was present in patients with a higher rate of dialysis. There were no differences in age and disc height, angle, or level between the two groups. CONCLUSIONS: Buckling of the ligamentum flavum coexists with tissue hypertrophy and contributes to perceived ligamentum thickening on imaging. Buckling of the ligamentum flavum tends to occur in less hypertrophied tissues and is associated with the grade of disc degeneration and the presence of other characteristics associated with spinal degeneration.

Efficacy of Self-Review of Lifestyle Behaviors with Once-Weekly Glycated Albumin Measurement in People with Type 2 Diabetes: A Randomized Pilot Study.

INTRODUCTION: Lifestyle management, including appropriate modifications of nutrition, exercise, and medication behaviors, is essential for optimal glycemic control. The absence of appropriate monitoring methods to validate the lifestyle change may hinder the modification and continuation of behaviors. In this study, we evaluated whether once-weekly glycated albumin (GA) measurement received via a smartphone application could improve glycemia management in patients with type 2 diabetes mellitus by supporting self-review and modification of lifestyle behaviors. METHODS: This open-label, randomized controlled, single-center study in Japan with an 8-week intervention period was conducted in individuals with type 2 diabetes mellitus and HbA1c levels between 7.0 and 9.0% (53‒75 mmol/mol). The intervention was once-weekly home monitoring of GA with a daily self-review of lifestyle behaviors using a smartphone application, in addition to conventional treatment. RESULTS: A total of 98 participants (72.0% males; age 63.2 ± 11.4 years; HbA1c 7.39 ± 0.39% [57.3 ± 4.3 mmol/mol]) were randomly assigned to the intervention or control group. Significant decreases of the GA and HbA1c levels from the baseline to the last observation day were observed in the intervention group (- 1.71 ± 1.37% [- 39.1 ± 31.3 mmol/mol] and - 0.32 ± 0.32% [- 3.5 ± 3.5 mmol/mol], respectively). Significant decreases of the body weight, waist circumference, and caloric expenditure (p < 0.0001 and p = 0.0003, p = 0.0346, respectively), but not of the caloric intake (p = 0.678), were also observed in the intervention group as compared with the control group. CONCLUSIONS: Self-review of lifestyle behaviors in combination with once-weekly GA home testing received via a smartphone application might potentially benefit glycemic management in people with type 2 diabetes mellitus. TRIAL REGISTRATION: jRCTs042220048.

Clinical Features Requiring Sacroiliac Joint Arthrodesis in Patients with Sacroiliac Joint Pain.

PURPOSE: This study aimed to reveal the clinical features requiring sacroiliac joint (SIJ) arthrodesis, which was performed for patients who complain of severe SIJ pain. METHODS: The differences in clinical features between a surgical treatment group (n=20) and a conservative treatment group (n=66) were investigated. All patients were definitively diagnosed with SIJ pain by the use of SIJ injections. RESULTS: Six significant features were identified in the surgical treatment group, namely, sitting tolerance (<15 minutes), walking with a cane, pain in the supine position, pain while lying on the painful side, numbness in the lower limbs, and any accident that induced SIJ pain (P<0.01). Univariate logistic regression analysis revealed that sitting tolerance <15 minutes (odds ratio : 31.73), pain in the supine position (13.07), and pain while lying on the painful side (18.30) showed a high odds ratio. CONCLUSIONS: Sitting tolerance (<15 minutes), walking with a cane, pain in the supine position, pain while lying on the painful side, numbness in the lower limbs, and a history of any accident that induced SIJ pain may be considered as indicators for surgery after >?6 months of continued substantial conservative treatment. J. Med. Invest. 70 : 123-128, February, 2023.

Numerical analysis of the effects of padded pelvic belts as a treatment for sacroiliac joint dysfunction.

BACKGROUND: Pain related to the sacroiliac joint (SIJ) accounts for low back pain in 15%-30% of patients. One of the most common treatment options is the use of pelvic belts. Various types of pelvic belts exist; however, the mechanisms underlying treatment and their effectiveness remain unclear to date. OBJECTIVE: To analyze stress distribution in the pelvis when a pelvic rubber belt or a padded pelvic belt is applied, to assess the effectiveness of treatment from a numerical biomechanical perspective. METHODS: The pressure distribution at the pelvic belts was measured using a device and subsequently modeled with the finite element method of a pelvis with soft tissues. The stress environment when wearing a pelvic belt in a double-leg stance was simulated. RESULTS: With the application of pelvic belts, the innominate bone rotated outward, which was termed an out-flare. This caused the SIJ to compress and cause reduction in sacrotuberous, sacrospinous, interosseous, and posterior sacroiliac ligament loading. Padded pelvic belts decreased the SIJ displacement to a greater extent than in pelvic rubber belts. CONCLUSION: Pelvic belts aid in compressing the SIJ and reduce its mobility.

Sacrotuberous Ligament Pain in Patients who Underwent Sacroiliac Joint Arthrodesis: Incidence and Management of Post-Surgical Lower-Buttock Pain.

Introduction: Most sacroiliac joint (SIJ) disorders are conservatively treated; however, patients with severe pain occasionally require SIJ arthrodesis after failure of continuous conservative management for more than 6 months. We investigated the incidences of preoperative tenderness in the sacrotuberous ligament (STL) and postoperative lower-buttock pain originating from the STL to determine the best way to manage these symptoms to achieve good outcomes. Methods: We retrospectively investigated 33 patients (14 men and 19 women) with a mean age of 47.7 years (range: 25-79 years) who underwent SIJ arthrodesis for severe pain confirmed using diagnostic SIJ injections between April 2009 and December 2019. We investigated the pain improvement at or around the posterior superior iliac spine (PSIS) pre- and postoperatively using the visual analogue scale (VAS) values, incidence of tenderness of the STL before surgery, rate of the persisting STL tenderness, incidence of new-onset STL pain, and treatment options for STL pain postoperatively. Results: The mean VAS value at or around the PSIS was significantly relieved postoperatively from 85.6 to 31.5 mm (P<0.001). Preoperative tenderness of the STL was identified in 21 of 33 patients (63.6%). The STL tenderness resolved after surgery in 12 of these 21 patients (57.1%); however, it persisted in nine patients (42.9%), all of whom were women. Of the 12 patients who did not have preoperative STL tenderness, 4 (33.3%) developed lower-buttock pain and had STL tenderness. In total, 9 (27.3%) of the 33 patients whose progress could be followed up after SIJ arthrodesis had pain originating from the STL; the STL pain in 8 of the 9 patients was relieved after the STL injections and physical therapy. Conclusions: The STL pain can occur pre- and postoperatively, and management of both persisting and new-onset STL pain after SIJ arthrodesis should be considered to achieve better outcomes.

Three-Year Clinical Outcomes after Minimally Invasive Sacroiliac Joint Arthrodesis Using Triangular Implants in Japan: A Pilot Study of Five Cases.

INTRODUCTION: Sacroiliac joint (SIJ) arthrodesis using a minimally invasive technique, particularly the triangular implant system, is performed in patients with SIJ dysfunction in the United States and Europe. We report three-year clinical outcomes of the first minimally invasive SIJ arthrodesis procedures using the implants performed in Japan. METHODS: Five patients (one man and four women; age: 56.4±16.9 years) with SIJ pain who underwent SIJ arthrodesis using a triangular implant system in 2017 were included. In addition to operation time and blood loss, pain intensity (visual analog scale [VAS]) and functional impairment (Oswestry disability index [ODI]) were assessed preoperatively and at a 36-month follow-up. Implant loosening and osseous bridging across the joint were evaluated using computed tomography images, and patients' satisfaction with the surgery was also assessed at 12 and 36 months. RESULTS: The surgical time was 67.7±13.1 minutes, and blood loss was 7.4±6.9 mL. The mean VAS value improved significantly from 88.0±8.4 mm to 33.6±31.9 mm at 3 months and was maintained at 46.4±30.9 mm at 36 months (P<0.05). The mean ODI improved significantly from 76.4%±3.8% to 46.2%±21.9% at 6 months postoperatively (P<0.05) but had no significant improvements thereafter: 46.94±23.7% (12 months) and 66.4±8.6% (36 months). Three of five patients presented with at least one implant loosening on the sacrum side. No patient had osseous bridging across the joint. A total of 80% (4/5) of patients reported satisfaction with the surgery at 12 months and 60% (3/5) at 36 months. CONCLUSIONS: The mean VAS value and ODI significantly improved until 6 months after the surgery. However, the mean ODI was reaggravated at 36 months after the surgery. Osseous bridging across the joint was not observed in all patients. We should carefully keep an eye on further long-term results to evaluate the implant.

A patient-cohort study of numerical analysis on sacroiliac joint stress distribution in pre- and post-operative hip dysplasia.

In acetabular dysplasia, the cartilaginous roof on the acetabular side does not fully cover the femoral head, which may lead to abnormal stress distribution in both the femoral head and pelvis. These stress changes may have implications to the adjacent sacroiliac joint (SIJ). The SIJ has a minimal range of motion and is closely coupled to the adjacent spine and pelvis. In consequence, the SIJ may react sensitively to changes in stress distribution at the acetabulum, with hypermobility-induced pain. The purpose of this study was to investigate the stress distribution of the SIJ in acetabular dysplasia, and to gain insight into the cause and mechanisms of hypermobility-induced pain at the SIJ. Finite element models of pre- and postoperative pelves of four patients with acetabular dysplasia were created and analyzed in double leg standing positions. The preoperative models were relatively inflare, the sacral nutation movement, SIJ cartilage equivalent stress, and the load on the surrounding ligaments decreased with increased posterior acetabular coverage. Acetabular morphology was shown to affect the SIJ, and improvement of the posterior acetabular coverage may help normalize load transmission of the pelvis and thus improve the stress environment of the SIJ in acetabular dysplasia.

The psoas major muscle is essential for bipedal walking - An analysis using a novel upright bipedal-walking android model.

BACKGROUND: Bipedalism is a unique function in humans. Various investigations in bipedal walking have assessed the kinetic chain from the pelvis to the lower limbs. However, few studies have investigated the functions of the upper body including the psoas major muscles. In the present study, a bipedal-walking human full-body skeletal model, "the bipedal android model", was generated by attaching air cylinder devices to simulate the contraction and relaxation of various muscles required for bipedal walking, including the psoas major muscles. The bipedal-walking principle was discussed using the model. METHODS: Every part of a human full-body skeletal model was connected by wires or cables to retain the mobility of each joint. Then the psoas major (PM), gluteus minimus (GM), long head of biceps femoris (BF), quadriceps femoris (QF), and semimembranosus (SM) muscles were simulated in the skeletal model using air cylinders. The gait pattern was observed by synchronizing the contraction of PM, GM, QF and SM, and relaxation of BF of the ipsilateral side together with the reversed patterns in the contralateral side, and then switching the phase by every step. The gait pattern in dysfunction of PM or GM muscles was also observed by disconnecting the corresponding air cylinders. RESULTS: The synchronized contraction of PM, GM, QF and SM generates the force to tilt the upper body to ipsilateral side, followed by elevation of the lower limb together with the forward rotation of the pelvis in the contralateral side to swing the leg forward. The next step was generated by reversing the contraction phase at the landing of the swung leg. The dysfunction of PM muscle disabled effective gait in the model, while GM did not. SIGNIFICANCE: The bipedal android model indicated that the psoas major muscles play a crucial role in bipedal walking in human.

Factors Associated with Thickening of the Ligamentum Flavum on Magnetic Resonance Imaging in Patients with Lumbar Spinal Canal Stenosis.

STUDY DESIGN: Experimental study of the ligamentum flavum (LF) thickness among patients with lumbar spinal canal stenosis (LSCS). OBJECTIVES: To elucidate the factors associated with thickening of the LF on magnetic resonance imaging (MRI). SUMMARY OF BACKGROUND DATA: Thickening of the LF is a major contributor to LSCS. This thickening is attributed to tissue hypertrophy or buckling of the ligament, and there may be several associated factors on MRI; however, these factors remain unclear. METHODS: We studied the LF in 56 patients (a total of 106 ligaments) with LSCS, who underwent decompressive surgery; among them, 23 were receiving haemodialysis. The Pearson correlation coefficient was used to assess relationships between the thickness of the LF on MRI and the thickness of the LF tissue, age, disc height, disc degeneration, and disc level. Patients were also categorised into 2 groups based on whether they were undergoing haemodialysis, and the relationships were assessed similarly. RESULTS: Among patients with LSCS, the thickness of the LF on MRI showed a significant positive linear relationship with the thickness of the LF tissue, and no association with disc height. Except for in those receiving haemodialysis, the thickness of the LF on MRI showed a significant positive relationship with age, disc degeneration, and disc level among patients with LSCS. CONCLUSION: In patients with LSCS, thickening of the LF on MRI appears to represent tissue hypertrophy. The association between the thickness of the LF on MRI and age, disc degeneration, and disc level may indicate simultaneous alterations of spine components along with aging that was cancelled by the effects of haemodialysis.

Surgical Outcomes of Patients with Sacroiliac Joint Pain: An Analysis of Patients with Poor Results Regarding Activities of Daily Living.

INTRODUCTION: Sacroiliac joint (SIJ) arthrodesis is the last resort for patients with severe SIJ pain. However, this technique does not always provide good outcomes regarding activities of daily living (ADL). This study aims to reveal the preoperative clinical features associated with poor outcomes of SIJ arthrodesis. METHODS: Twenty-six consecutive patients who underwent SIJ arthrodesis between 2009 and 2018 were evaluated. Good-outcome was defined as ≥30% improvement in ADL, quantified by the Roland-Morris Disability Questionnaire (RDQ). The good-outcome group (17 patients; 10 men and 7 women, 42.5±8.4 years old) and the poor-outcome group (9 patients; 1 man and 8 women, 47.0±17.9 years old) were compared to identify the preoperative clinical features of poor surgical outcomes. RESULTS: No significant differences were observed between the two groups regarding age, preoperative RDQ score, time between onset and the confirmed diagnosis of SIJ pain, and the time between diagnosis and surgical treatment. The following preoperative clinical features associated with poor surgical outcomes were identified: female sex, pain in multiple regions, walking with a cane, and the use of a wheelchair before surgery (P<0.05). CONCLUSIONS: The present study demonstrated that poor postoperative outcomes in patients with severe SIJ pain were associated with the following preoperative clinical features: female sex, pain in multiple regions, walking with a cane, or use of a wheelchair. Ample attention is warranted in patients with such features who are indicated for surgical treatments.

Subchondral Bone Changes Following Sacroiliac Joint Arthrodesis - A Morpho-mechanical Assessment of Surgical Treatment of the Painful Joint.

BACKGROUND: Sacroiliac joint arthrodesis is an ultima ratio treatment option for sacroiliac joint dysfunction. Fusion drastically reduces sacroiliac joint movement providing long-lasting pain-relief associated with tension-relief to the innervated sacroiliac joint structures involved in force closure. OBJECTIVES: To display the bone mineralization distribution patterns of the subchondral bone plate in 3 distinct regions (superior, anterior, and inferior) of the sacral and iliac counterparts of the sacroiliac joint pre- and post-sacroiliac joint arthrodesis and compare patterns of sacroiliac joint dysfunction post-sacroiliac joint fusion with sacroiliac joint dysfunction pre- arthrodesis patterns and those from healthy controls. STUDY DESIGN: An observational study. SETTING: The research took place at the University of Basel, Switzerland, where the specific image analysis program (Analyze, v7.4, Biomedical Imaging Resources, Mayo Foundation, Rochester, NY, USA) was made available. METHODS: Mineralization densitograms of 18 sacroiliac joint dysfunction patients pre- and post-sacroiliac joint arthrodesis (>= 6, >= 12, and >= 24 months post-surgery) were obtained using computed tomography osteoabsorptiometry. For each patient, pre- vs. post-surgery statistical comparisons were undertaken, using the Hounsfield unit values derived from the subchondral mineralization of superior, anterior, and inferior regions on the iliac and sacral auricular surfaces. Post-operative values were also compared to those from a healthy control cohort (n = 39). RESULTS: In the pre-operative cohort at all 3 follow-up times, the superior iliac region showed significantly higher Hounsfield unit values than the corresponding sacral region (P < 0.01). Mineralization comparisons were similar for the sacrum and ilium in the anterior and inferior regions at all follow-up points (P > 0.5) with no surgery-related changes. Sacral density increased significantly in the post-operative state; not observed on the ilium. Post-operative sacroiliac joints showed a significantly increased mineralization in the superior sacrum after >= 6 months (P < 0.05), not replicated after >= 12 nor >= 24 months. Further comparison of post-operative scans versus healthy controls revealed significantly increased mineralization in the superior sacral region at (>=) 6, 12, and 24 months (P < 0.01), likely related to bone grafting, and in the anterior and inferior regions in post-operative scans at >= 12 and >= 24 months follow-up (P < 0.05). LIMITATIONS: The given study is limited in sample size. Post-operative computed tomography scans had screws which may have left artifacts or partial volume effects on the surfaces. Healthy controls were different patients to the sacroiliac joint dysfunction and post-operative cohorts. Both cohorts were age-matched but this comparison did not take into account potential population differences. Size differences in the regions may have also been an influencing factor of the results as the regions were based on the size and shape of the articular surface. CONCLUSIONS: Sacroiliac joint arthrodesis results in an increased morpho-mechanical conformity in the anterior and inferior sacrum and reflects variable morpho-mechanical density patterns compared to the healthy state due to permanent alterations in the kinematics of the posterior pelvis.

Quantitative evaluation of the sacroiliac joint fixation in stress reduction on both sacroiliac joint cartilage and ligaments: A finite element analysis.

BACKGROUND: The sacroiliac joint fixation is the last resort for patients with prolonged and severe joint pain. Although the clinical results of anterior fixations are conclusive, there exist several inevitable drawbacks with the surgical method such as the difficulty performing the surgery due to the presence of many organs. The posterior fixation technique has thus been developed to overcome those inconveniences. This study aims to assess in silico the mechanical environment following posterior and anterior fixations, focusing on stresses in both the sacroiliac cartilage and dorsal ligamentous part, as well as loads experienced by the pelvic ligaments. METHODS: Sacroiliac joint cartilage, dorsal ligamentous part stresses and pelvic ligaments loads were evaluated with three types of fixation models. A vertical load of 600 N was applied, equally distributed via both acetabula when standing and sitting. FINDINGS: Results show that the anterior sacroiliac joint fixation reduced von Mises stresses in the cartilage and dorsal ligamentous part and decreased ligaments loads more extensively than the posterior fixation when compared to the untreated model as a reference. However, the posterior fixation still remains the desirable and preferential treatment. INTERPRETATION: The anterior sacroiliac joint fixation showed better performances compared to the posterior one; however, the lower invasive aspect of the latter is a fundamental clinical advantage which also has the possibility to be improved by considering various screws and cages configurations. This study provides a beneficial suggestion to improve the current fixation technique.

Finite element analysis of load transition on sacroiliac joint during bipedal walking.

The sacroiliac joint (SIJ) is burdened with variant loads. However, no methods have allowed to measure objectively how the SIJ deforms during bipedal walking. In this study, in-vivo walking conditions were replicated in a kinematic model combining the finite element method with 3D walking analysis data divided into five phases in order to visualize the load transition on the SIJ and clarify the role of the SIJ. Both models with and without inclusion of the SIJ were investigated. In models with bilateral SIJs, the displacement differed greatly between the sacrum and both hip bones on the SIJ as the boundary. The movements of the sacrum involved a nutation movement in the stance phase and a counter-nutation in the swing phase relative to the ilium. In models without SIJs, the displacement of the pelvis and loads of pelvic ligaments decreased, and the equivalent stress of the SIJs increased compared to the model with SIJs. The walking loads cause distortion of the entire pelvis, and stress concentration at the SIJ are seen due to the morphology of the pelvic ring. However, the SIJs help dissipate the resulting stresses, and the surrounding ligaments are likewise involved in load transmission.