BACKGROUND: Snapping hip syndrome (SHS) is characterized by snapping sensation and pain and affects up to 10% of the general population. External snapping hip syndrome (ESHS), the most common form, is often due to repetitive movements in sports or anatomical predispositions. Conservative treatment includes physiotherapy and corticosteroid injections, while surgery is considered if conservative measures fail. Open surgical techniques carry several risks, while modern arthroscopic techniques offer less invasive options, such as endoscopic iliotibial band release (ITB) and gluteus maximus tenotomy.
METHODS: A systematic review was conducted adhering to the PRISMA guidelines. Relevant studies were searched in four databases: Pubmed, Scopus, Embase, and Medline. The selected articles were evaluated according to the criteria of levels of evidence. The Risk of Bias In Non-randomized Studies of Interventions (ROBINS-I) was used to analyze the retrospective studies. This paper was registered in the International Prospective Registry of Systematic Reviews (PROSPERO).
RESULTS: Out of 9 included studies, 403 patients with 689 hips underwent endoscopic treatment. ITB release and his variations were the main surgical techniques. Gluteus maximus tenotomy was also used in some studies. Postoperative rehabilitation protocols varied. Patients generally experienced significant improvements in symptoms and functional outcomes, with low rates of recurrence (1.02%) and revision (0.15%). Complications were minimal.
CONCLUSIONS: Endoscopic treatment of ESH shows favorable results, improving functional outcomes and returning patients to pre-injury activity levels. Long-term efficacy and costeffectiveness need to be evaluated, emphasizing the importance of large-scale prospective randomized trials to clarify surgery\'s benefits in refractory ESH cases.

OBJECTIVE: Arthroscopic treatment is indicated for external snapping hip (ESH) syndrome in patients refractory to conservative treatment, but snapping does not disappear completely in some case. No previous studies have described the clinical course of ESH syndrome in patients who presented with persistent snapping after an arthroscopic procedure. We demonstrated the clinical outcomes following an incomplete arthroscopic iliotibial band (ITB) release for ESH syndrome.
METHODS: This retrospective observational study was performed at two teaching hospitals between October 2015 and December 2021. We reviewed the data of 33 patients (34 hips) aged ≥18 years, diagnosed with ESH syndrome, who were treated with arthroscopic ITB release. Patients who presented with persistent snapping despite sufficient arthroscopic ITB release following systematic order were defined as having an incomplete release. We collected the data for recurrent symptomatic snapping hip as the primary outcome after a minimum 2-year follow-up. The visual analogue scale (VAS) and modified Harris hip (mHHS) scores were measured as secondary outcome.
RESULTS: \"Incomplete release\" was identified in three of the 34 hips (8.9%). Cases of recurrent symptomatic snapping or conversion to open surgery were not observed. The symptoms of residual snapping spontaneously disappeared in all cases following routine postoperative rehabilitation within a 3-month follow-up period. The VAS (4 ± 1) and mHHS (17 ± 6) scores of all the patients improved.
CONCLUSIONS: When refractory ESH syndrome is identified during arthroscopic surgery, appropriate ITB release and removal of the major lesion causing snapping are expected to lead to resolution of residual symptoms without conversion to open surgery.

OBJECTIVE: External snapping hip syndrome (ESHS) was historically attributed to isolated iliotibial band (ITB) contracture. However, the gluteus maximus complex (GMC) may also be involved. This study aimed to intraoperatively identify the ESHS origin and assess the outcomes of endoscopic treatment based on the identified aetiological type.
METHODS: From 2008-2014, 30 consecutive patients (34 hips) with symptomatic ESHS cases refractory to conservative treatment underwent endoscopic stepwise \"fan-like\" release, gradually addressing all known reasons of ESHS: from the isolated ITB, through the fascial part of the GMC until a partial release of gluteus maximus femoral attachment occurred. Snapping was assessed intra-operatively after each surgical step and prospectively recorded. Functional outcomes were assessed via the MAHORN Hip Outcome Tool (MHOT-14).
RESULTS: Twenty seven patients (31 hips) were available to follow-up at 24-56 months. In all cases, complete snapping resolution was achieved intra-operatively: in seven cases (22.6%) after isolated ITB release, in 22 cases (70.9%), after release of ITB + fascial part of the GMC, and in two cases (6.5%) after ITB + fascial GMC release + partial release of GM femoral insertion. At follow-up, there were no snapping recurrences and MHOT-14 score significantly increased from a pre-operative average of 46 to 93(p<0.001).
CONCLUSIONS: Intraoperative identification and gradual addressing of all known causes of ESHS allows for maximum preservation of surrounding tissue during surgery while precisely targeting the directly involved structures. Endoscopic stepwise \"fan-like\" release of the ITB and GMC is an effective, tailor-made treatment option for ESHS regardless of the snapping origin in the patients with possibility to manually reproduce the snapping.

BACKGROUND: External snapping hip syndrome (ESH) is postulated to be one of the causes of greater trochanteric pain syndrome, which also includes greater trochanteric bursitis and tendinopathy or tears of the hip abductor mechanism. However, it was not yet described what kind of bony morphology can cause the snapping and whether symptomatic and asymptomatic individuals have different imaging features.
OBJECTIVE: It was the purpose of this study to look for predisposing morphological factors for ESH and to differentiate between painful and asymptomatic snapping.
METHODS: A consecutive cohort with ESH and available magnetic resonance imaging (MRI) between 2014 and 2019 was identified. The control group consisted of patients that underwent corrective osteotomies around the knee for mechanical axis correction and never complained of hip symptoms nor had undergone previous hip procedures. The following parameters were blindly assessed for determination of risk factors for ESH: CCD (corpus collum diaphysis) angle; femoral and global offset; femoral antetorsion; functional femoral antetorsion; translation of the greater trochanter (GT); posterior tilt of the GT; pelvic width/anterior pelvic length; intertrochanteric width. Hip and pelvic offset indexes were calculated as ratios of femoral/global offset and intertrochanteric/pelvic width, respectively. For the comparison of symptomatic and asymptomatic snapping, the following soft-tissue signs were investigated: presence of trochanteric bursitis or gluteal tendinopathy; presence of surface bony irregularities on trochanter major and ITB (Iliotibial band) thickness.
RESULTS: A total of 31 hips with ESH were identified. The control group (n = 29) consisted of patients matched on both age (± 1) and gender. Multiple regression analysis determined an increased hip offset index to be independent predictor of ESH (r =  + 0.283, p = 0.025), most likely due to the higher femoral offset in the ESH group (p = 0.031). Pearson correlation analysis could not identify any significant secondary factors. No differences were found between painful and asymptomatic snapping on MRI.
CONCLUSIONS: A high hip offset index was found as an independent predictor for external snapping hip in our cohort, mainly due to increased femoral offset. No imaging soft-tissue related differences could be outlined between symptomatic and asymptomatic external snapping.
UNASSIGNED: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors   www.springer.com/00590 .

OBJECTIVE: To determine the effectiveness of hip arthroscopy combined with endoscopic iliotibial band (ITB) release in patients with both femoroacetabular impingement (FAI) syndrome and external snapping hip (ESH).
METHODS: Retrospectively review the preoperative and minimum of 2-year follow-up data of patients with both FAI syndrome and ESH who underwent endoscopic ITB release during hip arthroscopy (FAI + ESH group) from January 2014 to December 2018. The same number of age- and gender-matched FAI syndrome patients without ESH undergoing hip arthroscopy were enrolled in the control group (FAI group). Patient-reported outcomes (PROs) including international Hip Outcome Tool (iHOT-33), modified Harris Hip Score (mHHS), visual analog scale for pain (VAS-pain), and abductive force of affected hip at 3 month and 2 years postoperatively were comparatively analyzed. The VAS-satisfaction score of two groups at 2 years postoperatively were also analyzed.
RESULTS: The prevalence of ESH in FAI syndrome patients undergoing hip arthroscopy in our institution was 5.5% (39 of 715 hips), including nine males (10 hips) and 29 females (29 hips). The mean age at the time of surgery was 32.1 ± 6.9 years (range, 22-48 years). According to inclusion and exclusion criteria, 23 patients were enrolled in FAI + ITB group. Twenty-three age- and sex-matched FAI syndrome patients were enrolled in FAI group. At 24 months postoperatively, no patient still suffered ESH symptoms and painful palpation at lateral region in FAI + ITB group. The iHOT-33, mHHS, and VAS-pain score of patients in FAI + ESH group were significantly severer than patients in FAI group preoperatively (41.6 ± 7.5 vs 48.8 ± 7.2, 54.8 ± 7.2 vs 59.2 ± 6.9, 5.5 ± 0.9 vs 4.7 ± 1.0; P < 0.05), while there was no significant difference in these scores between the patients in FAI + ESH group and FAI group at 3-month and 24-month follow-up (73.6 ± 8.5 vs 76.1 ± 6.9, 85.3 ± 7.8 vs 84.2 ± 6.6, 0.8 ± 0.9 vs 0.6 ± 0.9; P > 0.05). At 3 months after surgery, the abductive force of operated hip was significantly smaller than that in FAI group (82.4 ± 12.4 N vs 91.9 ± 16.1 N, P < 0.05), whereas there was no significant difference at 24 months after surgery (101.6 ± 14.9 N vs 106.5 ± 13.7 N, P > 0.05). The VAS-satisfaction scores of patients in the two groups were at a similarly high level (90.5 ± 6.8 vs 88.8 ± 7.3, P > 0.05). There was no complication and no arthroscopic revision in either group until 2-year follow-up.
CONCLUSIONS: Although abductive force recovery of the hip was delayed, hip arthroscopy combined with endoscopic ITB release addressed hip snapping in patients with both FAI syndrome and ESH, and could get similar functional improvement, pain relief, recovery speed, as well as patient satisfaction compared with the pure hip arthroscopy in FAI syndrome patients without ESH.

OBJECTIVE: Snapping hip is a common clinical condition, characterized by an audible or palpable snap of the hip joint. When the snap is perceived at the lateral side of the hip, this condition is known as external snapping hip or lateral coxa saltans, which is usually asymptomatic. Snapping hip syndrome (SHS) refers to a painful snap, which is more common in athletes who require increased hip range of motion. The aim of this article is to review the most common endoscopic techniques for the treatment of ESHS, as well as their results and limitations.
METHODS: This is a review of the current literature of endoscopic surgical procedures and of the results of the treatment of external snapping hip syndrome.
RESULTS: The pathogenesis of SHS is mechanical. The initial treatment attempt is conservative, and usually provides good results. Patients who do not respond to conservative management are candidate for surgery. The endoscopic release of the ilio-tibial band or the endoscopic release of the femoral insertion of the gluteus maximum tendon is the most popular technique.
CONCLUSIONS: Endoscopic techniques provide fewer complications compared to open surgery, a lower recurrence rate and good clinical outcomes. More comparative studies with a longer follow-up are required to adequate evaluate the full role of endoscopic techniques in periarticular hip surgery.
METHODS: Level V.

UNASSIGNED: Little is known about the feasibility of applying progressive resistance training (PRT) to patients with symptomatic external snapping hip (SESH).
UNASSIGNED: To investigate whether PRT is feasible in patients with SESH and to report changes to hip function, awareness of the hip joint and muscle strength following PRT.
UNASSIGNED: Feasibility was measured by drop-out rate, adverse events, pain exacerbation (VAS) and adherence to PRT. At baseline and the end of treatment, patients completed the Copenhagen Hip and Groin Outcome Score (HAGOS), the Forgotten Joint Score (FJS), maximal voluntary isometric (MVC) and dynamic hip muscle strength and a loaded stair test (LST).
UNASSIGNED: Three out of nine included female patients (33%) dropped out. Pain scores were acceptable (VAS ≤ 50 mm) in 76% of all training sessions, and an overall decrease in pain during PRT was found (-10 mm, 95% CI [-3; -18]). For those who completed the intervention, training adherence was 97 ± 4%. Paired analyzes showed improvements in all HAGOS subscales, FJS, muscle strength and the LST.
UNASSIGNED: Progressive resistance training seems feasible in a subset of patients with SESH despite a high drop-out rate. The present study suggests large effect sizes for hip pain, function, awareness and muscle strength.

OBJECTIVE: To evaluate the outcomes of surgical management for external snapping hip in terms of: (1) recurrence; (2) complications; and (3) return to pre-injury activities.
METHODS: A thorough review of 4 electronic databases- EMBASE, CINAHL Plus, PubMed, and Scopus was performed to find all relevant studies for this review that were published between January 2000 and January 2017 that addressed surgical treatment for external snapping hip. The following reports were excluded: (1) non-English manuscripts; (2) n ⩽ 5; (3) clinical reviews; (4) surgical technique notes; (5) studies only analysing diagnosis; and (6) nonoperative management studies. After cross-referencing, a total of 7 reports were included. Each of these studies was analysed for the incidence of recurrence, revision surgery, complications, and return to pre-injury activity level.
RESULTS: There was a recurrence rate of 7% ( n = 8 of 113 hips) with only 1 requiring revision surgery (1%). The cumulative complication rate was 9% ( n = 10 of 113) with all complications being residual weakness. Additionally, we found 98% ( n = 58 of 59) of the patients returned to their pre-injury level of activity.
CONCLUSIONS: We found operative treatment for external snapping hip to be both safe and efficacious for returning patients to their pre-injury activities. When recurrence does occur, it often is painless and does not require revision surgery. Future studies should be larger and evaluate different surgical techniques to further elucidate the safety and efficacy of surgical treatment for external snapping hip.

OBJECTIVE: To compare the outcomes of contracture release by arthroscopic versus open surgical approach in patients with external snapping hip (ESH) caused by gluteal muscle contracture (GMC).
METHODS: Medical records of patients with ESH due to GMC who underwent open surgery (n = 44) or arthroscopic surgery (n = 48) between October 2008 and October 2014 were reviewed. Patients were followed up at 1, 3, 12, and 24 months postoperatively. Operation time, incision length, postoperative pain, postoperative complication rate, and recurrence rate were compared between the 2 groups. Hip adduction, and Harris Hip Scores (HHS) at 1 and 2 years postoperatively were compared between the groups and with preoperative data.
RESULTS: Mean operation time did not differ between the 2 groups (p>0.05). The arthroscopic surgery group had smaller incisions (p<0.05), less postoperative pain (p<0.05), lower complication rates (p<0.05) than did the open surgery group. The recurrence rates were similar for the 2 groups (p>0.05). Hip adduction, and HHS 1 year and 2 years postoperatively were significantly better postoperatively than they had been preoperatively for both groups (all p<0.01), and were similar for the 2 groups (all p>0.05).
CONCLUSIONS: Arthroscopic release of contracture tissue is a safe and effective approach for the treatment of ESH caused by GMC, with the advantages of small scars, less postoperative pain, fewer complications compared with open surgery.

OBJECTIVE: The purpose of this study is to present the effective design of N-plasty of the iliotibial band and surgical results of its use as a treatment for refractory external snapping hip.
METHODS: We evaluated 17 patients (24 cases) with external snapping hip who underwent N-plasty between October 2013 and May 2016 and who were followed up for at least 12 months. All patients were male and the mean age was 20.8 years. The mean duration of symptoms prior to surgical intervention was 28.5 months with an average follow up of 24.5 months. Surgery was defined as being successful when patients could carry out their daily activities and exercise without a clicking sensation or pain 6 months after surgery until their last follow-up. Failure was defined when either a clicking sensation or pain was present. The visual analog scale (VAS) and modified Harris hip score (mHHS) were measured and compared preoperatively and at last follow-up.
RESULTS: All patients had complete resolution of pain and snapping. The VAS decreased from 6.77 preoperatively to 0.09 postoperatively and mHHS improved from 69.5 to 97.8 after surgery.
CONCLUSIONS: Modified designed N-plasty is considered to be an excellent treatment method facilitating operation reproducibility with maximum elongation effect of the iliotibial band.