between january 2009 and december 2011 , we performed arthroscopic iliopsoas tendon release in 25 patients followed up for a minimum of 2 years postoperatively . the indications for surgery were an audible and painful popping sound of the iliopsoas attachment area and intractable pain after preoperative conservative treatment , manifest as limitation of patient 's activity , physical therapy , and/ or the need for medications and injections for at least 12 weeks . on physical examination , all patients had a painful range of motion and a positive impingement test ( flexion , adduction , and internal rotation ) . preoperative imaging included plain radiographs ( pelvis anteroposterior and frog leg ) and computed tomography arthrogram or magnetic resonance arthrogram to detect bony impingement and labral lesons . patients who had undergone previous hip surgery , and who had avascular necrosis , rheumatologic disorder , and arthritis more severe than tonnis grade 2 were excluded . the 25 patients comprised 20 men and 5 women , with a mean age of 32 years ( range , 17 to 53 years ) . preoperative diagnoses included internal snapping hip with isolated labral tear in 6 hips , cam - type impingement in 14 hips , pincer - type impingement in 3 hips , and mixed type in 2 hips . preoperative radiographs revealed tonnis grade 0 to 1 changes in 23 hips and grade 2 changes in 2 hips ( table 1 ) . during surgery , all patients had ilipsoas tendon release combined with another procedure ; arthroscopic femoroplasty with labral repair was performed in 16 patients , chondroplasty in 3 patients , and labral repair or debridement in 6 patients . arthroscopy was performed with the patient supine on a fracture table , with the post for counter - traction in the central position and a well - padded foam cushion in place to protect against any nerve compression . complete inspection of the central compartment was performed , with care to evaluate for the presence of injury to any part of the labrum , articular cartilage damage , or pincer lesion . in cases with a tear of the labrum , the traction was released and the peripheral compartment entered via anterolateral and anterior portals with the hip in 30 flexion to open the space anteriorly over the hip . for exposure of the tendinous portion of the iliopsoas , further capsulotomy was made anterior to the labral injury using the shaver or radiofrequency ablation device . a 30 arthroscope was introduced into the anterolateral portal aiming caudally and set on the femoral head - neck junction . with the arthroscope pointing toward the anterior capsule , an 8-mm transverse capsulotomy was made just lateral to the medial synovial fold and just proximal to the zona orbicularis anteriorly , directly under the iliopsoas tendon.13 ) through this capsular window , the tendinous portion of the iliopsoas could be visualized ( fig . 1 ) . the shaver was used to peel any adherent portions of the iliopsoas off of the capsule . the tendinous portion of the iliopsoas was then incised through an anterior portal from medial to lateral using arthroscopic electrocautery ( fig . careful attention was paid to avoid damage to any of the nearby neurovascular structures ( supplement 1 
 ) . the surgery was completed with a thorough inspection of the peripheral compartment with care to note the presence of a cam lesion or capsular - sided labral abnormality . clinical and radiographic follow - up evaluations were performed at 6 weeks , 3 , 6 , and 12 months , and every 6 months thereafter . clinical evaluations were performed using the harris hip score ( hhs),14 ) visual analog pain score ( vas ) , hip outcome score ( hos)-activities of daily living subscale and hos - sports subscale . radiographic analysis included anteroposterior view of the pelvis , frog - leg lateral view , and cross - table lateral view of the hip . all radiographs were assessed using the tonnis classification15 ) to grade radiographic degenerative changes and the outerbridge classification system16 ) that grades according to the degree of chondromalacia . the difference between preoperative and postoperative outcome measures were analyzed using wilcoxon signed rank test for continuous outcome measures and fisher exact test for categorical outcome measures . the null hypotheses of no difference was rejected if p - values were < 0.05 . statistical analyses used spss ver . 15.0 ( spss inc . , chicago , il , usa ) . the design and protocol of this retrospective study were approved by the institutional review board of chung - ang university hospital , seoul , korea . snapping sounds and pain had disappeared at the 2-year follow - up in 24 of the 25 patients . during follow - up , significant loss of flexion strength in all patients was present after surgery but improved by 6 to 10 weeks . the overall rating for the 25 patients ( 25 hips ) using the hhs was 65 points ( range , 46 to 86 points ) preoperatively and 84 points ( range , 67 to 98 points ) postoperatively ( p < 0.001 ) . seven hips ( 28% ) had an excellent score , 15 hips ( 60% ) a good score , 2 hips ( 8% ) a fair score , and one hip ( 4% ) a poor score . the hos - activities of daily living subscale and hos - sports subscale preoperatively were 66% and 60% , respectively . the score changed to 87% and 82% , respectively , at the final follow - up evaluation . university of california , los angeles ( ucla ) activity at the latest follow - up was improved in 17 patients and remained the same in 8 patients . the mean vas score decreased from 6 to 2 at the latest follow - up . five patients had an outerbridge grade iii articular cartilage lesion of the acetabulum at the time of the surgical exploration . the tonnis grade of osteoarthritis did not change in any of the patients at the last follow - up . although significant complications such as infection , heterotopic ossification , thromboembolic episode or permanent nerve injury did not occur , one patient had a reoperation because of recurred painful snapping hip 3 days postoperatively . snapping sounds and pain had disappeared at the 2-year follow - up in 24 of the 25 patients . during follow - up , significant loss of flexion strength in all patients was present after surgery but improved by 6 to 10 weeks . the overall rating for the 25 patients ( 25 hips ) using the hhs was 65 points ( range , 46 to 86 points ) preoperatively and 84 points ( range , 67 to 98 points ) postoperatively ( p < 0.001 ) . seven hips ( 28% ) had an excellent score , 15 hips ( 60% ) a good score , 2 hips ( 8% ) a fair score , and one hip ( 4% ) a poor score . the hos - activities of daily living subscale and hos - sports subscale preoperatively were 66% and 60% , respectively . the score changed to 87% and 82% , respectively , at the final follow - up evaluation . university of california , los angeles ( ucla ) activity at the latest follow - up was improved in 17 patients and remained the same in 8 patients . the mean vas score decreased from 6 to 2 at the latest follow - up . five patients had an outerbridge grade iii articular cartilage lesion of the acetabulum at the time of the surgical exploration . the tonnis grade of osteoarthritis did not change in any of the patients at the last follow - up . although significant complications such as infection , heterotopic ossification , thromboembolic episode or permanent nerve injury did not occur , one patient had a reoperation because of recurred painful snapping hip 3 days postoperatively . good - to - excellent clinical outcomes after arthroscopic release of internal snapping hip have been reported since the year 2000 . however , most of the reported studies have focused on the surgical techniques used and the clinical outcomes of isolated internal snapping.9,10,11,17 ) this study was done to evaluate clinical outcomes after combined arthroscopic iliopsoas tendon release and other arthroscopic procedures in patients with internal snapping and other intracapsular pathologies . twenty - four of 25 patients experienced disappearance of the snapping sound and 22 patients ( 88% ) had scores indicating excellent and good responses over the minimal 2-year follow - up period ( table 2 ) . in 2006 , they reported that the snapping symptoms disappeared in all patients over the average 21-month follow - up period and significant loss of flexion strength was present after surgery but had improved by 8 weeks . in 2009 , ilizaliturri et al.11 ) performed a prospective randomized study of two different techniques for endoscopic iliopsoas tendon release in 19 patients . the western ontario and mcmaster universities ( womac ) scores in both groups improved without complications . flanum et al.18 ) reported all 6 patients in the case series reported no recurrence of their snapping or pain at the last follow - up . however , in this study , all patients had combined internal hip pathologies such as labral tear ( 6 patients ) and femoroacetabular impingements ( 19 patients ) . they observed anterior labral tears at the 3 o'clock area and suggested that iliopsoas impingement is one of the causes of labral tear in the hip . fabricant el al.17 ) evaluated the clinical outcomes of 67 patients with internal snapping hip who underwent arthroscopic psoas tendon lengthening . thirty - seven of these patients had combined structural pathologies . also , increased femoral anteversion was reported as a risk factor for inferior clinical outcomes after arthroscopic lengthening for symptomatic internal snapping hip . patients with internal snapping hip might have combined hip pathologies . however , during open surgical treatment of internal snapping hip , it may be difficult to evaluate and treat combined internal hip pathologies such as structural bony abnormalities , labral tear , and femoral anteversion.12,17 ) recently , khan et al.19 ) performed a systemic review using 11 eligible studies . they reported that arthroscopic surgery for internal snapping hip syndrome showed a decreased failure rate , fewer complications , and decreased postoperative pain in comparison with open management.19 ) a possible reason for the better outcomes after arthroscopic iliopsoas tendon release is that combined intraartcular hip pathologies can easily be treated during this procedure . we think that clinical outcomes after iliopsoas tendon release might be related to the treatment of combined hip pathologies . the medial femoral circumflex artery is close to the psoas tendon.20 ) theoretically , there is a risk of osteonecrosis of the femoral head after injury to the medial femoral circumflex artery during arthroscopic psoas tendon release . however , to our knowledge , there has been no report of medial femoral circumflex artery injury during arthroscopic psoas tendon release , and it did not occur in this study . presently , rehabilitation after arthroscopic iliopsoas tendon release was delayed and a crutch was needed for a longer time than after typical arthroscopic hip surgery because of loss of flexion strength . others reported that significant loss of flexion strength was present after surgery but improved by 8 weeks.10 ) in the present study , all patients who had presented with loss of flexion strength postoperatively showed recovery by week 6 to 10 . therefore , patients should be told about the inevitable loss of flexion strength and the longer rehabilitation period plus the longer period of crutch use that occur after this procedure . first , it is a retrospective review of prospectively collected data and no control group was used , it might be hard to know what effect the psoas tendon release had on the overall results . however , we are sure of the reliability of our study because all patients had painful snapping hip and completed the follow - up for the minimum 2-year period . second , all patients had combined hip pathology . it might be difficult to evaluate the effect of arthroscopic iliopsoas release on internal snapping hip only when there is combined hip pathology . in addition , patients with internal snapping hip should be thoroughly evaluated and a plan made for the treatment of combined pathology such as structural bony abnormalities , labral tear , and femoral anteversion . dynamic ultrasound is a well - suited , complementary tool for diagnosing snapping hip because of its real - time visualization of the snapping structures . this diagnostic method might be helpful to evaluate painful internal snapping hip . however , dynamic ultrasound technique was not available in this study period . therefore , the surgeon should keep in mind the possibility that painful internal snapping hips can frequently accompany concomitant intraarticular pathologies . a video clip is available in the electronic version of this paper at the cios web site , www.ecios.org .
backgroundarthroscopic iliopsoas tendon release was introduced in 2000 . 
 the purpose of this study was to evaluate clinical outcomes of arthroscopic iliopsoas tendon release for painful internal snapping hip with concomitant hip pathologies.methodsbetween january 2009 and december 2011 , we performed arthroscopic iliopsoas tendon release and related surgeries in 25 patients ( 20 men and 5 women ; mean age , 32 years ; range , 17 to 53 years ) with combined intraarticular hip pathologies . 
 the patients were followed for a minimum of 2 years postoperatively . 
 clinical and radiological evaluations were performed.resultssnapping sounds had disappeared by the 2-year follow - up in 24 of the 25 patients . 
 all patients who had presented with loss of flexion strength postoperatively showed recovery at postoperative week 6 to 10 . 
 harris hip score improved from 65 points ( range , 46 to 86 points ) preoperatively to 84 points ( range , 67 to 98 points ) postoperatively ( p < 0.001 ) . 
 seven hips ( 28% ) had an excellent score , 15 hips ( 60% ) a good score , 2 hips ( 8% ) a fair score , and one hip ( 4% ) a poor score ( p < 0.001 ) 
 . the tonnis grade of osteoarthritis did not change in any of the patients at the last follow-up.conclusionspatients with painful internal snapping hip have combined hip pathologies . 
 therefore , the surgeon should keep in mind that painful internal snapping hips are frequently combined with concomitant intraarticular pathologies .