Minimally invasive treatment for idiopathic chondrolysis of the hip: analysis of forty-one cases.

PURPOSE: Idiopathic chondrolysis of the hip is characterized by the loss of the articular cartilage of the hip joint with spectrum ranging from full recovery to fibrous ankylosis. Study assessed outcomes following intra-articular steroid injections, joint manipulation and traction immobilization. METHODS: Retrospective (2012-2021) review of 41 cases treated for idiopathic chondrolysis of hip, assessed pre-operatively and post-operatively (minimum 2-year follow-up) using Children's Hospital Oakland Hip Evaluation Score (CHOHES), visual analogue scale (VAS) and range of motion measurements. RESULTS: Twenty-five patients (62%) achieved painless mobility, 6 (14%) had hip stiffness without pain and 10 (24%) had painful and stiff hips at final follow-up. They had a mean age of 12.49 ± 2.4 years and a mean follow-up duration of 33.15 ± 13.1 months. Range of motion improved significantly (p < 0.05). VAS improved to 3.93 ± 1.3 from 7.8 ± 0.7. CHOHES improved from 29.12 ± 9.9 to 56.37 ± 17.6. CONCLUSION: Intra-articular steroid injection, manipulation and traction immobilization may effectively treat idiopathic chondrolysis of the hip by enhancing patient function and reducing the need for further surgical intervention.

Comparison between effects of instrument-assisted soft tissue mobilization and manual myofascial release on pain, range of motion and function in myofascial pain syndrome of upper trapezius - A randomized controlled trial.

Background: Myofascial pain syndrome (MPS) is a muscle pain disorder characterized by the presence of Myofascial Trigger Point (MTrP) within a taut band, local tenderness, referral of pain to a distant site, restricted range of motion, and autonomic phenomena. The upper trapezius is the muscle most often affected by MTrPs. Manual myofascial release (MFR) and Instrument-Assisted Soft Tissue Mobilization (IASTM) are techniques of soft tissue release that are used to resolve MPS. Fifty six percent of physiotherapists complain of pain in multiple areas due to the massage and manual therapy that they have to perform. Objective: The objective of this study is to find whether IASTM is better than manual MFR in treating patients with MPS in upper trapezius. Methods: This study was a single-blinded randomized controlled trial that included 31 participants, both males and females between the age groups of 18-50 years. Participants were randomly divided into two groups. Three sessions were given over a period of one week for both groups. Group A received IASTM along with conventional treatment and Group B received Manual MFR along with the conventional treatment. The outcome measures evaluated were pain, cervical range of motion, pain pressure threshold (PPT) of trigger points, and the neck disability index. Pre- and post-measurements were taken and the analysis was done. Results: Both the treatment methods significantly reduced pain, improved PPT, range of motion, and function. The effects between the groups showed that IASTM was significantly better than manual MFR to reduce pain. The improvement in PPT, range of motion and function were equal in both the groups. Conclusion: IASTM and manual MFR both are effective individually as treatment procedures for pain, PPT, range of motion, and function. Neither of the treatment options can be considered better that the other. The clinician can decide based on the availability of the instrument, training, patient's preference, and his/her comfort whether which of the two treatment methods should be used.

Analysis of the Characteristics and Intricacies of Arrangement of Neural Elements in the Costoclavicular Block Using Ultrasound: A Retrospective Qualitative Study.

Background: Ultrasound (US)-guided costoclavicular block (CCB) is a promising new approach to brachial plexus (BP) block which is increasingly being utilized. Conventionally, the costoclavicular space (CCS) has been described to contain three cords. However, there may be variations in the neural pattern of the BP which is important to know to prevent inadvertent injury. We intend to describe the variations in neural patterns from retrospective scans of patients receiving costoclavicular BP block. Methods: The stored US images of patients who had received BP block using the CCB for surgery at the level of the elbow or below in the last year (from March 2021 to March 2022) were analyzed by two investigators independently. The clinical data were retrieved from the records of the same patients for the study outcomes. We collated the variations of the neural pattern, the number of neural structures seen, and the echogenicity of the structures in the costoclavicular BP space. Results: In the CCS, the median number of neural structures was 4.5 (minimum of 3 to maximum of 8). With the BP lateral to the axillary artery and sandwiched between the subclavius-pectoralis minor superiorly and the serratus anteriorly inferiorly, numerous variations in the neural structures were noted. The most common arrangement was caterpillar-like (28.6%) and pecker-like (20.3%). The neural structures were found to be hypoechoic in the majority (66%). Conclusion: The CCS hosts several mostly hypoechoic neural structures which may be the variations of the cords or the extension of BP divisions. These new findings have been unreported in the recent past.

Ultrasound-guided Parasagittal Infraclavicular Block for Patients without Neurostimulation Endpoints: A Case Report in Crush Injuries of the Upper Limb.

Evoked motor responses (distal muscle responses) to a specific nerve stimulation are considered an endpoint. Often in crush injuries of the upper limb below the level of the elbow, the distal muscle responses are irrelevant. We report 14 cases of crush injuries of the upper limb that underwent an amputation below the level of the elbow. A parasagittal ultrasound-guided infraclavicular block without neurostimulation was administered in all patients. A reliable local anesthetic (LA) spread either in the perineural or perivascular area is considered adequate. Adequate intraoperative anesthesia and postoperative analgesia were achieved with the deposition of LA beneath the axillary artery.

Efficacy of less Invasive modified O-arm navigated delta fixation in osteoporotic high-grade spondylolisthesis: "a LIMO delta technique".

PURPOSE: In 1994, the technique of transdiscal screws fixation in spondylolisthesis was introduced but did not gained popularity as it failed to address problems with spinal sagittal imbalance, retroverted pelvis, pseudoarthrosis, implant failure and neural injury. Majority of problems were due to lack of clear indications; hence, in this study, with modification of traditional technique and use of O-arm navigation for selected group of patients, we have addressed the above problems and given good to excellent functional outcomes. METHODS: We did prospective study on 15 patients with osteoporotic high-grade spondylolisthesis Meyerding grade 3 & 4 admitted in period 2020-2021. Intraoperative assessment was done in form of blood loss, incision length, operative time and complications. The preoperative & postoperative assessment was done in the form of clinical and radiological parameters. RESULTS: The average follow-up was of 21.2 months (18-24 months). There was no significant difference between pre- & postoperative spinopelvic parameters. Intraoperative average blood loss was 100 ml (90-120 ml) with mean surgical time of 138 min (120-150 min). Incision length was about 5-6-cms-posterior midline with two paraspinal 1-cm incisions for transdiscal screws. Patients were mobilized on postoperative day-2. There was statistically significant improvement in mean ODI, COMI and VAS for LBP and radicular pain with no intra- or postoperative complication observed till latest follow-up with all patients showing solid monoblock fusion on 1-year follow-up CT scan. CONCLUSIONS: LIMO delta technique is a newly modified version of conventional transdiscal screw technique. Minimal incision, decreased blood loss & operative time with in situ 3-column rigid fixation and solid fusion minimizing risk of complications makes this novel technique safer, simpler & effective in osteoporotic HGS.

Learning curve across 2000 thoracolumbar pedicle screw placements using O-arm navigation: technical difficulties and their solutions.

INTRODUCTION: Instrumentation using the intraoperative O-arm navigation technique appears safer than its predecessor techniques. However, only a handful of surgeons often used navigation during spinal surgeries. Too many operative glitches and unreliable navigation accuracy were the important reasons cited even by experienced surgeons for not using spinal navigation. We have studied the accuracy of pedicle screw placement during the learning curve and beyond it. We have also discussed in detail the intricacies of the technique and solutions to the difficulties encountered using spinal navigation. MATERIALS AND METHODS: A total of 2000 thoracolumbar pedicle screws have been placed in the 324 spine surgeries meeting the inclusion and exclusion criteria included in this retrospective study. We have divided 2000 pedicle screw placements into consecutive groups of 200 each. We have compared these groups for the accuracy of screw placement with the surgeon's experience. RESULTS: The accuracy of pedicle screw placement using the "in-versus-out" grading system in group 1 was 85.5% which significantly increased in group 2 to 93.5% (p-value: 0.0099), and thereafter, there was a nonsignificant increase in subsequent groups with the graph achieving the shape of a plateau. CONCLUSION: Surgeons should learn the correct principles of the technique of O-arm navigation to prevent the loss of accuracy and place pedicle screws with high accuracy. There is a learning curve of around 30-35 surgeries or 200 pedicle screw placements to acclimatize with the technique of O-arm navigation and learn its principles.

The Paraneural Sciatic Sheaths in Longitudinal Axis at the Level of Greater Trochanter: An Ultrasound Cadaveric and Clinical Correlation Study.

Background: Paraneural sheath engulfing the sciatic nerve (SN) between the ischial tuberosity and the greater trochanter is well known. Methods: In order to explore the anatomical planes separating the paraneurium from the epineurium in SN, we conducted a cadaveric study (two patients and four specimens), followed by a clinical study in 10 patients. Results: We demonstrated an elevation of 5-7 layers of paraneural tissues after an in-plane injection in the longitudinal axis of the proximal SN, which was possibly the last of the paraneural sheath. In the clinical study, the block provided low pain scores with no rescue analgesia postoperatively and no neurological deficit at the time of discharge. Conclusion: This is probably the first series which has described the elevation of several layers of paraneural tissues after an in-plane injection in the longitudinal axis of the proximal SN.

Prophylaxis for preventing venous thromboembolism in knee arthroscopy and soft tissue reconstruction: consensus statements from an international panel of experts.

PURPOSE: There is a lack of consensus regarding need for Venous Thrombo Embolism (VTE) prophylaxis following arthroscopic knee surgery and open soft tissue knee reconstruction. Clear cut guidelines like ones for trauma surgery and arthroplasty do not exist and the published literature is limited to case reports with a few society guidelines. Given this lack of consensus, we conducted a modified Delphi questionnaire of international experts to provide recommendations on this topic. METHODS: The consensus statements were generated using an anonymised 3 round modified Delphi questionnaire, sent to an international panel of 38 knee surgeons, with an 80% agreement being set as the limit for consensus. The responses were analysed using descriptive statistics with measures like mode, median and box plots. Feedback was provided to all panelists based on responses from the previous rounds to help generate the consensus. RESULTS: Six consensus statements were generated after the three rounds of Delphi. Patient factors, prolonged surgery duration and family history of thrombogenic events emerged as the main points to be taken into consideration for prophylaxis. CONCLUSION: It was established through this study, that there exists a select group of patients undergoing arthroscopic surgery that justify the usage of VTE prophylaxis. The expert responses to most of the questions in different scenarios favoured usage of VTE prophylaxis based on patient factors like advanced age, past history of VTE, smoking, oral contraceptive use etc. LEVEL OF EVIDENCE: Level V.

Standalone cage versus anchored cage for anterior cervical discectomy and fusion: a comparative analysis of clinical and radiological outcomes.

PURPOSE: The use of standalone cages (SAC) and anchored cages (AC) in anterior cervical discectomy and fusion surgery (ACDF) has shown advantage of reduced operative time and lower incidence of dysphagia. However, there is limited literature available comparing the clinical and radiological outcomes of SAC and AC. METHODS: We conducted a prospective study for patients undergoing ACDF for cervical radiculopathy or myelopathy. Patient were classified based on the cage used into SAC group and the AC group. Clinical outcomes were assessed using the modified Japanese Orthopedic Association (mJOA) for myelopathy and Neck Disability Index (NDI) and Visual Analogue Scale (VAS) for radiculopathy. Dysphagia was graded as per Bazaz score. Radiologically, global cervical lordosis, segmental lordosis, cage subsidence, and migration were assessed. RESULTS: We analyzed 31 patients in each group with a minimum two year follow-up. The mean VAS improved from 7.9 to 4.56, mean NDI score improved from 27.6 to 19.8, and mean mJOA improved from 10.8 to 11.7 which were statistically significant (p < 0.05); however, no significant difference was noted between the SAC and AC groups. Mean global lordosis improved from 14.4 to 20.3° and mean segmental lordosis improved from 6 to 10.1° at six months and plateaued to 6.9° at final follow up without any significant difference between the groups. The subsidence was statistically more in 12.9% (4/31) in SAC than 6.4% (2/31) in AC. CONCLUSION: AC showed of lower rates of subsidence while both SAC and AC had comparable clinical outcomes and radiological alignment outcomes.

Intricacies of Ultrasound-guided Lumbar Plexus Block in Octogenarians: A Retrospective Case Series.

Background: Ultrasound (US)-guided lumbar plexus block (LPB) could be technically challenging in elderly patients. The lumbar paravertebral sonoanatomy is undescribed in the elderly. In an attempt to understand the relevant sonoanatomy, identify the lumbar plexus elements, and understand the difficulties that encountered while performing LPB in elderly patients, we retrospectively analyzed US of 23 elderly patients who were administered US-guided LPBs. Methods: After institutional ethics committee approval, we retrospectively reviewed stored US images of lumbar paravertebral sonoanatomy in 23 elderly patients and analyzed psoas major muscle, lumbar vertebral body, lumbar nerve, and lumbar artery. Results: On US examination, features of psoas major muscle, lumbar vertebral body, lumbar nerve, and lumbar artery were noted and analyzed. Conclusion: US-guided visualization of the components of the lumbar paravertebral area is difficult and inconsistent in the elderly. Therefore, we suggest performing a scout scan, identify the structures, and use neurostimulation all the time for performing LPB in these patients.

Sciatic Nerve Hemangioma, a Challenge in Klippel-Trenaunay Syndrome for Perioperative Analgesia.

Children with Klippel-Trenaunay syndrome have vascular malformations, varicosities at unusual distribution, and unilateral soft and skeletal tissue hypertrophy of the lower extremity. Corrective surgery of the deformity is necessary to improve gait and wear acceptable footwear. Perioperative pain relief for debulking of the right great toe in a known case of KTS with sciatic hemangioma was achieved with ultrasound-guided sciatic nerve block in an avascular area.

Low-volume ultrasound-guided supraclavicular block in a multicomorbid patient for emergency vascular surgery - In COVID-19 era.

Supraclavicular block is the most commonly used block in upper limb surgeries, right from the day it was introduced into clinical practice in Germany by Kulenkampff in 1911. The block underwent many changes in its application due to the advent of peripheral nerve stimulator and ultrasonographic application in regional anesthesia. This case report focuses on supraclavicular block's application in a multicomorbid patient, the drug dose required, and how the scope of regional anesthesia can be extended in times of pandemic, like coronavirus disease 2019 (COVID-19), in coming future.

Undescribed Vascular Signatures: A Contraindication to Ultrasound-guided Parasagittal Infraclavicular Block! A Retrospective Observational Study.

BACKGROUND: The ultrasound-infraclavicular block (US-ICB) is a popular and efficient block for below-elbow surgeries. However, the vascular anatomy of infraclavicular area close to the brachial plexus has remained unresearched. We aimed to explore the presence of aberrant vasculature in the infraclavicular area that could pose a contraindication to US-ICB. METHODS: In this retrospective observational study, we reviewed the US images of patients undergoing below-elbow surgery under US-ICB. Before performing the block, a scout scan of parasagittal infraclavicular areas was performed and the scan images were saved. The primary objective was to find the prevalence of aberrant vasculature due to which the US-ICB was abandoned. The secondary objective was to understand the pattern and position of the aberrant vessels. RESULTS: Out of 912 patients, 793 patients underwent surgery under US-ICB and in 119 patients (13.05%), the USG-ICB was abandoned due to aberrant vasculature close to the brachial cords and intended position of the needle tip. The anomalous vessels were identified in the lower inner, lower outer, and upper outer quadrants around the axillary artery (AA). Some of these vascular structures also had classical patterns which we described as "satellites," "clamping," or "hugging" of the AA. CONCLUSION: Anomalous vascular structures in the infraclavicular area were seen in 13.05% of patients planned for US-ICB. We, therefore, recommend, that a thorough scout US scan should be mandatorily performed ICB and in the presence of aberrant vascular structures, an alternative approach to brachial plexus block may be adopted.

Flow dynamics of ultrasound-guided lumbar plexus block in adults.

Background and Aims: The outcomes of plexus and peripheral nerve blocks depend on needle-nerve contact and the spread of local anesthetic (LA) around the plexus or nerve. Needle-nerve distance and spread of LA could be visualized during US-guided lumbar plexus block (LPB). Material and Methods: After Institutional Ethics Committee approval and after obtaining informed consent, 24 American Society of Anesthesiologists'-physical status I-III patients who underwent surgical fixation of fractures of proximal femur were enrolled. Spinal anesthesia was a primary anesthetic in all patients. At the end of the surgery, all patients received US and neurostimulation-aided LPB at the third lumbar nerve root (LNr). The primary aim was to determine the spread of LA in the lumbar plexus area with the relation of the needle tip and LNr contact. The secondary aim was to understand block efficacy in terms of pain scores monitored at regular intervals and 100 mg intravenous tramadol was administered as a rescue analgesic if VAS >4. Results: In all 24 patients, we observed an oval and antegrade LA spread after lumbar plexus was identified with neurostimulation at L3. With the needle closer to intervertebral foramina (IVF), a retrograde spread was visualized. Only 2/24 patients received rescue analgesia in the first 24 h. Conclusion: The type of spread after the US-guided LPB could predict block success of block and a possible epidural spread.

Surgical correction of Sprengel's deformity by modified Woodward procedure: outcomes in twenty eight patients.

PURPOSE: Sprengel's deformity is a congenital failure of the descent of the scapula with main concerns regarding cosmetic deformity and restricted function of the affected shoulder. The purpose of this study was to present the results of Modified Woodward procedure in 28 patients with Sprengel's shoulder. METHODS: Twenty-eight patients (9 males, 19 females) of Sprengel's shoulder treated with modified Woodward procedure from 2010 to 2016 were retrospectively studied. Clinical assessment was done using Cavendish grading and Rigault's classification for radiographic evaluation. RESULTS: Mean age at the time of surgery was six years and three months. Mean follow-up was 20 months. We found a mean increase in abduction of 34.2° (15-50) and flexion of 20.6° (10-25), mean scapular lowering of 2.3 cm (0.5-4.5 cm), and a Cavendish grade I in 18 (65%), grade II in 10 (35%). Thus, we had 65% satisfactory results in terms of cosmesis and 85% with the function of the affected limb. Rigault grading improved by one grade in 16 children and by two grades in 12 children. Subjectively, all parents were satisfied with the cosmetic appearance of the achieved scapular lowering. We had one case of delayed superficial wound healing which resolved spontaneously. CONCLUSION: Modified Woodward procedure for Sprengel's shoulder deformity gives good cosmetic correction and improvement in shoulder function with minimal complications. This procedure is good for selective cases of Cavendish grade II with cosmetic concerns and all cases of Cavendish grade III and IV.

Effects of muscle energy technique on pain, range of motion and function in patients with post-surgical elbow stiffness: A randomized controlled trial.

BACKGROUND: Elbow is a very functional joint. Elbow stiffness is a significant cause of disability hampering the function of the upper extremity as a whole. Muscle Energy Techniques (METs) are relatively pain-free techniques used in clinical practice for restricted range of motion (ROM). OBJECTIVE: To study the effects of MET on pain, ROM and function given early in the rehabilitation in post-surgical elbow stiffness. METHODS: An RCT was conducted on 30 patients post elbow fracture fixation. Group 1 was given MET immediately post removal of immobilization while Group 2 received MET 1 week later along with the rehabilitation protocol. Pain (Visual Analogue Scale), ROM (goniometry) and function (Disability of Arm, Shoulder and Hand questionnaire) were assessed pre and post 3 weeks. RESULTS: Group 1 showed greater improvement than Group 2, mean flexion and extension change between groups being 11 . 7 ± 2 . 8 , 95%CI(5.9,17.4) and 8 . 5 ± 2 . 0 , 95%CI(4.4,12.7), respectively. VAS and DASH scores improved better in Group 1, mean change being 1 . 2 ± 0 . 2 , 95%CI(0.6,1.8) and 18 . 2 ± 2 . 2 , 95%CI(13.5,22.8) for VAS and DASH scores, respectively. CONCLUSION: MET can be used as an adjunct to the rehabilitation protocol to treat elbow stiffness and can be given safely in the early stages of post elbow fracture rehabilitation managed surgically with open reduction and rigid internal fixation.

A Trial of Wound Irrigation in the Initial Management of Open Fracture Wounds.

BACKGROUND: The management of open fractures requires wound irrigation and débridement to remove contaminants, but the effectiveness of various pressures and solutions for irrigation remains controversial. We investigated the effects of castile soap versus normal saline irrigation delivered by means of high, low, or very low irrigation pressure. METHODS: In this study with a 2-by-3 factorial design, conducted at 41 clinical centers, we randomly assigned patients who had an open fracture of an extremity to undergo irrigation with one of three irrigation pressures (high pressure [>20 psi], low pressure [5 to 10 psi], or very low pressure [1 to 2 psi]) and one of two irrigation solutions (castile soap or normal saline). The primary end point was reoperation within 12 months after the index surgery for promotion of wound or bone healing or treatment of a wound infection. RESULTS: A total of 2551 patients underwent randomization, of whom 2447 were deemed eligible and included in the final analyses. Reoperation occurred in 109 of 826 patients (13.2%) in the high-pressure group, 103 of 809 (12.7%) in the low-pressure group, and 111 of 812 (13.7%) in the very-low-pressure group. Hazard ratios for the three pairwise comparisons were as follows: for low versus high pressure, 0.92 (95% confidence interval [CI], 0.70 to 1.20; P=0.53), for high versus very low pressure, 1.02 (95% CI, 0.78 to 1.33; P=0.89), and for low versus very low pressure, 0.93 (95% CI, 0.71 to 1.23; P=0.62). Reoperation occurred in 182 of 1229 patients (14.8%) in the soap group and in 141 of 1218 (11.6%) in the saline group (hazard ratio, 1.32, 95% CI, 1.06 to 1.66; P=0.01). CONCLUSIONS: The rates of reoperation were similar regardless of irrigation pressure, a finding that indicates that very low pressure is an acceptable, low-cost alternative for the irrigation of open fractures. The reoperation rate was higher in the soap group than in the saline group. (Funded by the Canadian Institutes of Health Research and others; FLOW ClinicalTrials.gov number, NCT00788398.).

Reliability and validity of a new clinical test for assessment of the sacroiliac joint dysfunction.

BACKGROUND: Dysfunctional sacroiliac joint (SIJ) has been cited as a source of low backache (LBA). Numerous non-invasive clinical tests are available for its assessment having poor validity and reliability which challenges their clinical utility. Thus, introduction of a new clinical test may be necessary. OBJECTIVE: To assess reliability and validity of a new clinical test for the assessment of patients with SIJ movement dysfunction. METHODS: Forty-five subjects (23 having LBA of SIJ origin and 22 healthy asymptomatic volunteers) with mean age 28.62 + ∕- 5.26 years were assessed by 2 blinded examiners for 3 different clinical tests of SIJ, including the new test. The obtained values were assessed for reliability by intraclass correlation, kappa coefficient and percentage agreement. Validity was assessed by averaging sensitivity and specificity. Positive and negative predictive values and accuracy were assessed. RESULTS: The new test demonstrates good intra- ( r = 0.81 ) and inter-rater ( r = 0.82 ) reliability with substantial agreement between raters ( k > 0.60 ) . It has 79.9% validity, 82% sensitivity, 77% specificity, 79% positive-predictive, 80% negative-predictive value and accuracy. CONCLUSION: The new "Shimpi Prone SIJ test" has a good intra- and inter-rater reliability with a substantial rater agreement and a good validity and accuracy for the assessment of patients with SIJ movement dysfunction.

The efficacy of multiple versus single hyaluronic acid injections: a systematic review and meta-analysis.

BACKGROUND: Intra-articular hyaluronic acid (IA-HA) is a common therapy used to treat knee pain and suppress knee inflammation in knee osteoarthritis (OA), typically prescribed in regimens ranging from a single injection to 5 weekly injections given once weekly. We conducted a systematic review to determine the efficacy of IA-HA, with subgroup analyses to explore the differences in knee pain and adverse events (AEs) across different dosing regimens. METHODS: We conducted a systematic search of the literature to identify studies evaluating IA-HA for the management of knee OA compared to IA-saline. Primary outcome measure was the mean knee pain score at 13 Weeks (3 months) or 26 weeks (6 months). Secondary outcome was the number of treatment-related AEs and treatment-related serious adverse events (SAEs). We evaluated differences in levels of pain and AEs/SAEs between dosing regimens compared to IA-Saline. RESULTS: Thirty articles were included. Overall, IA-HA injections were associated with less knee pain compared to IA-Saline injections for all dosing regimens. 2-4 injections of IA-HA vs. IA-Saline produced the largest effect size at both 3-months and 6-months (Standard mean difference [SMD] = -0.76; -0.98 to -0.53, 95% CI, P < 0.00001, and SMD = -0.36; -0.63 to -0.09 95% CI, P = 0.008, respectively). Additionally, single injection studies yielded a non-significant treatment effect at 3 and 6 months, while ≥5 5 injections demonstrated a significant improvement in pain only at 6 months. Five or more injections of IA-HA were associated with a higher risk of treatment-related AEs compared to IA-Saline (Risk ratio [RR] = 1.67; 1.09 to 2.56 95% CI, p = 0.02), which was a result not seen within the 1 and 2-4 injection subgroups. CONCLUSION: Overall, 2-4 and ≥5 injection regimens provided pain relief over IA-Saline, while single injection did not. Intra-articular injections of HA used in a 2-4 injection treatment regimen provided the greatest benefit when compared to IA-Saline with respect to pain improvement in patients with knee OA, and was generally deemed safe with few to no treatment-related AEs reported across studies. Future research is needed to directly compare these treatment regimens.