Acetabular labral tears

Prevalence of Asymptomatic Acetabular Labrum Abnormalities in the Active Pediatric Population

BACKGROUND

The prevalence of labral tears in asymptomatic active adults has been reported, but the prevalence of labral tears and other incidental hip lesions in the asymptomatic active pediatric population remains unclear. The purpose of this study was to determine the prevalence of hip abnormalities detected on 3T MRI in an active pediatric population with no hip symptoms and to compare with hip abnormalities found in children and adolescents who underwent an MRI for a hip-related condition.

METHODS

After IRB approval, pediatric patients self-reporting as athletes and presenting with isolated, acute-onset knee pain requiring knee MRI were prospectively recruited to undergo 3T MRI of their asymptomatic contralateral hip (ASx). A comparison group of pediatric subjects who underwent an MRI for hip pain was enrolled retrospectively (Sx). All MRI scans were anonymized and randomized. Fifty subjects were enrolled for each cohort. Two fellowship-trained musculoskeletal radiologists independently evaluated MRIs for abnormal hip lesions, including labral tears. Inter-reader reliability was evaluated using Cohen Kappa. χ 2 or Fisher exact test was used to compare the prevalence of hip lesions between the 2 cohorts.

RESULTS

The average patient age was 14.9 years for both cohorts (range 9 to 18 y) and 48% were male. In the ASx group, incidental labral tears were found in 18%, labral/paralabral cysts 6%, cartilage lesion 0%, subchondral cyst 0%, ligamentum teres tear 0%, femoral fibrocystic change 0%, cam lesion 30%, acetabular bone edema 0%, acetabular rim fracture 0%. The prevalence of labral tears (30%, P -value 0.16) and cam lesion (36%, P -value 0.52) in the Sx group was not significantly different from the ASx cohort. No significant correlation was found between the presence of femoral neck osseous bump and labral tear, labral cyst, or paralabral cyst in either cohort.

CONCLUSIONS

Labral tears were present on 3T MRIs of active pediatric patients with and without hip pain. Although MRI is essential to confirm the surgeon's suspicion and to detect unexpected pathology, clinical examination and history are crucial in pinpointing clinically relevant abnormal imaging findings.

LEVEL OF EVIDENCE

Level III.

Current understanding of articular cartilage lesions in femoroacetabular impingement syndrome

The concept of femoroacetabular impingement syndrome (FAIS) has received much attention over the past 20 years. Currently, it is believed that FAIS can lead to intra-articular pathologies such as labral tears and articular cartilage lesions, resulting in clinical symptoms and subsequent poor clinical outcomes. FAIS-related articular cartilage lesions are common but unique, and their natural course always leads to early osteoarthritis of the hip. However, despite these cartilage lesions having gradually gained considerable attention, limited consensus has been reached on key aspects, such as diagnosis, mechanisms, classification, and management strategies, which limits clinical and research advances. Hence, an intensive comprehensive overview based on the existing evidence is necessary. The purpose of this review was to introduce the general consensus, controversial issues, and recent advances in FAIS-related articular cartilage lesions.

Neither Bone Marrow Aspirate Concentrate nor Platelet-Rich Plasma Improves Patient-Reported Outcomes After Surgical Management of Acetabular Labral Tears; However, Bone Marrow Aspirate Concentrate May Be Effective for Moderate Cartilage Damage: A Systematic Review

Purpose

To (1) systematically assess which orthobiologic agents are being used in acetabular labral repairs and (2) report all available outcomes for patients undergoing operative management for labral repairs with orthobiologic agents.

Methods

The PubMed, Embase, and Cochrane databases were queried in August 2023. Articles were included if they used an orthobiologic agent during hip arthroscopy for acetabular labral repair and reported functional outcomes. Each study was queried for demographic data, orthobiologic agent used, volume of agent used, imaging modality used to guide administration, follow-up period, and all reported outcomes. The following Boolean phrase was used to systematically search the current literature: ((Orthobiologics) OR (Platelet-rich plasma) OR (PRP) OR (Mesenchymal stem cells) OR (MSCs) OR (Hyaluronic acid) OR (Growth factors) OR (bone marrow aspirate) OR (BMAC)) AND (hip joint OR (acetabular labrum) OR (Chondrolabr∗ damage) OR (Chondrolabr∗ tear)) AND (outcome∗ OR function∗ OR PROM OR PRO OR arthr∗ OR image OR pain OR complication).

Results

Three studies met the inclusion criteria and included 201 patients who received treatment with orthobiologic agents. Of these patients, 119 (59.7%) were women, with age ranging from 35 to 49 years. Ninety-seven patients (48.3%) received bone marrow aspirate concentrate (BMAC), and 104 (51.7%) received platelet-rich plasma (PRP). Both BMAC studies showed no significant improvements compared with controls; however, a subanalysis limited to patients with moderate cartilage damage who received BMAC showed significantly improved 2-year patient-reported outcome measures (International Hip Outcome Tool 33 score, 82.5 vs 69.5; P = .03). The one PRP study did not show significant improvements compared with controls. No complications were noted after either PRP or BMAC harvesting and application in any included study.

Conclusions

Overall, BMAC and PRP do not significantly improve patient-reported outcome measures compared with controls. However, there is limited evidence that BMAC may help patients with moderate cartilage damage.

Level of Evidence

Level III, systematic review of Level II and III studies.

A New Clinical Examination Algorithm to Prescribe Conservative Treatment in People with Hip-Related Pain

Hip-related pain is a common issue in active adults affecting their quality of life, mobility, and overall function, and it can lead to persistent disability. However, diagnosing hip-related pain is challenging due to the many potential sources and causes, including intra-articular and extra-articular pathology, and referred pain from other areas (lumbar or groin related pain). To address this, there is a need for a clinical algorithm based on the best available evidence and expert consensus. This algorithm could guide healthcare professionals in assessing and managing patients with hip-related pain, during the diagnosis, test selection, intervention, monitoring, and promoting collaboration among various healthcare providers. This clinical algorithm for hip-related pain is a comprehensive, flexible, adaptable to different settings, and regularly updated to incorporate new research findings. This literature review aims to establish a clinical algorithm specifically for prescribing exercise treatment to patients with hip-related pain, addressing their individual needs and enhancing their overall care.

The correlation between hip alpha angle and acetabular labral tear location and size: A cross-sectional study

BACKGROUND

Explore the correlation between hip morphology and labral tear location/size.

METHODS

This retrospective study analyzed patients with hip pain who received magnetic resonance (MR) arthrography at our institution, between January 2017 and December 2020. Imaging analysis includes labral tear location and size, and hip morphology measurement with alpha angle, lateral center-edge (CE) angle, anterior CE angle, and femoral neck version. The correlation between hip morphology angles and labral tear location/size was evaluated using multiple regression, followed by stratification analysis with Chi-square test to investigate interactions between the variables.

RESULTS

A total of 103 patients (105 hips) with hip pain who received MR arthrography (mean age, 50 years ± 15 [SD]) were included, with mean alpha angle of 57.7° ± 9.9° [SD], mean lateral CE angle of 32.6° ± 6.8° [SD], mean anterior CE angle of 58.2° ± 8.1° [SD], mean femoral neck version of 17.1° ± 8.2° [SD]. Large alpha angle (>57°) and older age were both correlated with superior and posterosuperior labral tear incidence ( p < 0.05) and larger tear size ( p < 0.05). Furthermore, alpha angle is significantly correlated with superior labral tear incidence in young-age subgroup (age <45 years) ( p < 0.05), also significantly correlated with posterosuperior labral tear incidence and larger tear size in middle-age subgroup (45 ≤ age ≤ 60 years) ( p < 0.05).

CONCLUSION

A large alpha angle (>57°) is significantly correlated with increased incidence of superior and posterosuperior labral tear, and larger tear size in patients with hip pain, and the relationships depend on age.

Evaluation of additional causes of hip pain in patients with femoroacetabular impingement syndrome

Femoroacetabular impingement syndrome (FAIS) is an increasingly prevalent pathology in young and active patients, that has contributing factors from both abnormal hip morphology as well as abnormal hip motion. Disease progression can be detrimental to patient quality of life in the short term, from limitations on sport and activity, as well as the long term through early onset of hip arthritis. However, several concurrent or contributing pathologies may exist that exacerbate hip pain and are not addressed by arthroscopic intervention of cam and pincer morphologies. Lumbopelvic stiffness, for instance, places increased stress on the hip to achieve necessary flexion. Pathology at the pubic symphysis and sacroiliac joint may exist concurrently to FAIS through aberrant muscle forces. Additionally, both femoral and acetabular retro- or anteversion may contribute to impingement not associated with traditional cam/pincer lesions. Finally, microinstability of the hip from either osseous or capsuloligamentous pathology is increasingly being recognized as a source of hip pain. The present review investigates the pathophysiology and evaluation of alternate causes of hip pain in FAIS that must be evaluated to optimize patient outcomes.

Acetabular labral tear is associated with high pelvic incidence with or without femoroacetabular impingement morphology

PURPOSE

The aim of this study was to investigate the association between pelvic sagittal parameters and acetabular labral tears.

METHODS

Three-hundred and sixty-five patients (449 hips) who underwent magnetic resonance imaging (MRI) or magnetic resonance arthrogram (MRA) for hip pain were enrolled in this study. Pelvic sagittal parameters, including the pelvic incidence, pelvic tilt, and sacral slope, were measured with a standing lumbosacral lateral radiograph. All subjects were divided into two groups according to the presence or absence of radiologic acetabular labral tears and compared. Furthermore, the two groups were divided into subgroups according to whether femoroacetabular impingement (FAI) morphology was present or not and compared.

RESULTS

Pelvic incidence was greater in the labral tear group than in the non-labral tear group (52.3° ± 8.2° versus 47.1° ± 6.8°, p < 0.001). After accounting for potentially confounding variables, we found that higher age (odds ratio 1.04, 95% confidence interval [CI] 1.02 to 1.06, p = 0.001), FAI (odds ratio 15.11, 95% CI 7.43 to 30.75, p < 0.001), and high pelvic incidence (odds ratio 1.13, 95% CI 1.09 to 1.17, p < 0.001) were independently associated with acetabular labral tear. When only the patients without FAI (308 hips) were divided into groups with and without acetabular labral tear, we found that higher age (odds ratio 1.03, 95% CI 1.01 to 1.06, p = 0.008) and high pelvic incidence (odds ratio 1.15, 95% CI 1.11 to 1.19, p < 0.001) were independently associated with acetabular labral tear.

CONCLUSION

Acetabular labral tear is associated with high pelvic incidence with or without FAI morphology.

LEVEL OF EVIDENCE

III.

Arthroscopic assessment of concomitant intraarticular pathologies in patients with osteonecrosis of the femoral head

This study's purpose is to arthroscopically assess the occurrence of intraarticular pathologies in patients with osteonecrosis of the femoral head (OFNH) and to compare arthroscopic with radiologic findings. In a retrospective cohort analysis of ONFH patients undergoing combined core decompression (CD) and hip arthroscopy, concomitant intraarticular pathologies were qualitatively and quantitatively assessed by means of arthroscopy. Intraoperative findings were compared with preoperative radiodiagnostics. Descriptive statistics were performed with results displaying type, degree and prevalence of co-pathologies. Based on a cohort of 27 hips with ONFH at ARCO stages II and III, 26 (96.3%) presented with concomitant intraarticular findings. Cam-deformity (n = 22; 81.5%), labral defects (n = 23; 85.2%) and chondral defects (n = 20; 74.1%) were the most frequent. Four hips (14.8%) had foveal ligament anomalies. Intraoperative detection of cam-deformity positively correlated with radiologically assessed pathologic α angles (p = 0.09). Radiologic evaluation of the acetabular labrum distinctly differed from arthroscopic findings. Reliable statements concerning the cartilage status were not possible due to the great difference in quality of the magnetic resonance imaging (MRIs). The results of this study revealed an arthroscopically proven prevalence of co-pathologies in >95% of patients with ONFH. Cam-type deformity, labral anomalies and chondral defects were the most frequent. Comparison of arthroscopic and radiologic findings showed coherent results regarding cam-deformity but revealed distinct difficulties in the assessment of the labral and chondral status emphasizing the need for standardization of preoperative radiodiagnostics. Moreover, it still has to be evaluated whether combined CD and arthroscopy can improve on the overall outcomes achieved by performance of CD only.

The Hip Suction Seal, Part II: The Effect of Rim Trimming, Chondrolabral Junction Separation, and Labral Repair/Refixation on Hip Distractive Stability

BACKGROUND

The acetabular labrum contains free nerve endings, and an unstable labrum can result in increased femoral head movement during hip motion. This can be caused by chondrolabral junction (CLJ) separation, especially in association with pincer-type femoroacetabular impingement, and may contribute to hip pain.

HYPOTHESIS

Rim resection alone has no effect on suction seal biomechanics. Further, separation of the CLJ changes hip suction seal biomechanics when compared with those of the native state, whereas repair and refixation with suture anchors restore these biomechanical parameters.

STUDY DESIGN

Controlled laboratory study.

METHODS

A total of 12 fresh-frozen human cadaveric hips were used in this study. Hips were mounted in a saline bath on a dynamic tensile testing machine and were distracted at a rate of 0.5 mm/s from neutral position. A total of 3 parameters (force, displacement, and intra-articular pressure) were measured throughout testing. Before testing, hips were randomly allocated to 1 of 2 groups: 1 that included the CLJ separation (CLJ Cut group) and 1 that did not (CLJ Intact group). Hips were tested in the following states: (1) native, (2) rim trimming, (3) separated CLJ (CLJ Cut group only), and (4) labral repair/refixation. For each group a linear mixed-effects model was used to compare biomechanical parameters between states.

RESULTS

Rim trimming did not affect any suction seal parameters relative to those of the native state. In the CLJ Cut group, no significant difference in distance to break the suction seal was observed for any states compared with that of the native state. In the CLJ Intact group, the distance to break the suction seal was significantly shorter in the labral refixation state (1.8 mm) than the native state (5.6 mm; P = .002). The maximum distraction force (62.1 ± 54.1 N) and the peak negative pressure (-36.6 ± 24.2 kPa) of the labral repair/refixation state were significantly lower than those of the native state in both groups (93.4 ± 41.7 N, P = .01; -60.7 ± 20.4 kPa, P = .02).

CONCLUSION

Rim trimming did not change the biomechanical properties of the labral suction seal. Labral refixation resulted in a shorter distance to break the labral suction seal. This indicates that labral mobility is reduced by the labral refixation procedure, which could be beneficial in postoperative pain relief and labral healing.

CLINICAL RELEVANCE

The labral refixation reduced labral mobility, which could be beneficial for both pain relief and labral healing to the acetabulum after pincer-type femoroacetabular impingement resection.

Outcomes After Arthroscopic Repair in Patients With Tears of Hypertrophic Versus Morphologically Normal Acetabular Labra

BACKGROUND

Recently, a hypertrophic labrum has been reported in the absence of hip dysplasia, which can possibly contribute to an acetabular labral tear.

PURPOSE

To compare the clinical outcomes and complications, including the incidence of iatrogenic acetabular labrum and cartilage injury, in patients with tears of hypertrophic versus morphologically normal acetabular labra over a minimum follow-up period of 2 years and to assess the morphologic changes at follow-up computed tomography arthrography in the 2 groups.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

Between January 2010 and December 2016, 20 patients (22 hips) with a hypertrophic labrum underwent arthroscopic hip surgery. A total of 22 patients (22 hips) without a hypertrophic labrum were assigned to the control group based on matching criteria, including age, sex, body mass index, labral tear, and labral repair. Clinical outcomes were assessed with the visual analog scale score, UCLA activity scale score (University of California, Los Angeles), and modified Harris Hip Score. Radiologic outcomes were assessed through serial radiography. Patients were followed for at least 2 years.

RESULTS

The mean age at surgery was 42 years. The most common cause of arthroscopic surgery in the study group was an isolated acetabular labral tear without any bony structural abnormalities (68.2%, 15 of 22 hips). All improvements in both groups were statistically significant at the last postoperative follow-up (P < .001). Although the radiologic and clinical outcomes were not significantly different between the groups, the complication rates, including iatrogenic labral perforations and cartilage injury, were significantly higher in patients with hypertrophic acetabular labral tears (9 vs 3, P = .042). The patient-reported satisfaction scores at the last postoperative follow-up were 8.4 and 7.9 in the study and control groups, respectively (P = .351).

CONCLUSION

The high rates of patient-reported satisfaction and the clinical outcomes after arthroscopic repair in both groups are encouraging. Arthroscopic treatment in patients with hypertrophic acetabular labral tears should be carefully performed to prevent iatrogenic injury during the surgery, and isolated hypertrophic labral tears can have good results after repair.

Evaluating and managing acetabular dysplasia in adolescents and young adults

Hip dysplasia is a developmental deformity in which abnormal acetabular or proximal femoral growth causes structural instability of the hip joint due to inadequate bony coverage of the acetabulum over the femoral head. Skeletally mature adolescents or young adults with underlying acetabular dysplasia may present with activity-related groin or lateral hip pain and a limp. This article reviews the current understanding of the disease and better treatment options for correcting acetabular dysplasia in symptomatic adolescents and young adults before secondary osteoarthritis develops.

Minimal Clinically Important Difference and Substantial Clinical Benefit Values for a Pain Visual Analog Scale After Hip Arthroscopy

PURPOSE

To define minimal clinically important difference (MCID) and substantial clinical benefit (SCB) values for a pain visual analog scale (VAS) in patients undergoing hip arthroscopy for femoroacetabular impingement or chondrolabral pathology.

METHODS

This was a retrospective review of prospective collected data on patients having hip arthroscopy for femoroacetabular impingement and/or chondrolabral pathology. On initial assessment and follow-up between 335 and 395 days postsurgery, subjects completed a pain VAS and categorical self-rating of function. MCID was calculated using one-half the standard deviation (SD) of the change in 1-year pain VAS values. Receiver operator characteristic analysis was performed to determine SCB values. A change in SCB value was determined based on change in categorical self-rating of function to create "improved" and "not improved" groups. Absolute postoperative SCB scores were calculated to determine scores that would be associated with "normal" or "abnormal" function ratings.

RESULTS

Of 1,034 eligible patients, 733 (71%) met the inclusion criteria, with 537 (73%) women and 196 (27%) men having a mean age of 35.3 years (SD 13). At a mean of 352 (SD 21) days postsurgery, 536 (73%) were in the improved group and 197 (27%) in the not improved group. MCID was -15.0 mm. A change of -22.7 mm on the pain VAS was able to identify those that improved with high sensitivity (0.74) and specificity (0.63). Values of ≤10.4 mm and ≥29.0 mm were cutoffs identifying subjects that rated their function as normal or abnormal, respectively, with high sensitivity (0.79 and 0.76) and specificity (0.88 and 0.76).

CONCLUSIONS

This study provides surgeons with information to help interpret pain VAS values at a follow-up period ranging from 335 to 395 days with MCID and SCB values of -15.0 mm and -22.7 mm, respectively. Additionally, a patient who assesses a pain level at ≤10.4 mm is likely to have a normal rating of function, whereas a patient who assesses a pain level at ≥29.0 mm is likely to have an abnormal rating of function.

LEVEL OF EVIDENCE

III, retrospective comparative study.

Acetabular retroversion: Diagnosis and treatment

Acetabular retroversion (AR) consists of a malorientation of the acetabulum in the sagittal plane. AR is associated with changes in load transmission across the hip, being a risk factor for early osteoarthrosis. The pathophysiological basis of AR is an anterior acetabular hyper-coverage and an overall pelvic rotation.

The delay or the non-diagnosis of AR could have an impact in the overall management of femoroacetabular impingement (FAI). AR is a subtype of (focal) pincer deformity.

The objective of this review was to clarify the pathophysiological, diagnosis and treatment fundaments inherent to AR, using a current literature review.

Radiographic evaluation is paramount in AR: the cross-over, the posterior wall and ischial spine signs are classic radiographic signs of AR. However, computed tomography (CT) evaluation permits a three-dimensional characterization of the deformity, being more reliable in its recognition.

Acetabular rim trimming (ART) and periacetabular osteotomy (PAO) are the best described surgical options for the treatment of AR.

The clinical outcomes of both techniques are dependent on the correct characterization of existing lesions and adequate selection of patients.

Cite this article: EFORT Open Rev 2018;3:595-603. DOI: 10.1302/2058-5241.3.180015

Atraumatic Hip Instability

Atraumatic hip instability is an increasingly recognized source of pain and hip dysfunction. It can result from numerous causes, including femoroacetabular impingement, prior trauma, injury to the capsuloligamentous structures, and idiopathic etiologies. Occult hip instability can be a challenging diagnosis that requires careful attention to, and interpretation of, history, physical examination, and radiographic imaging findings. Iatrogenic hip instability is a potential complication of both open and arthroscopic hip-preserving surgical procedures that can have catastrophic results. Atraumatic hip instability is a pathologic entity that can be successfully addressed with open and arthroscopic procedures.

Dynamic shear analysis: a novel method to determine mechanical integrity of normal and torn human acetabular labra: Implications for prediction of outcome of repair

Objectives

The aim of this study was to investigate the structural integrity of torn and non-torn human acetabular labral tissue.

Methods

A total of 47 human labral specimens were obtained from a biobank. These included 22 torn specimens and 25 control specimens from patients undergoing total hip arthroplasty with macroscopically normal labra. The specimens underwent dynamic shear analysis using a rheometer to measure storage modulus, as an indicator of structural integrity.

Results

There was a significant difference in the storage modulus between torn (mean modulus = 2144.08 Pa) and non-torn (3178.1 Pa) labra (p = 0.0001).

Conclusion

The acetabular labrum of young patients with a tear has significantly reduced structural integrity compared with a non-torn labrum in older patients with end-stage osteoarthritis. This study contributes to the understanding of the biomechanics of labral tears, and the observation of reduced structural integrity in torn labra may explain why some repairs fail. Our data demonstrate that labral tears probably have a relatively narrow phenotype, presenting a basis for further investigations that will provide quantifiable data to support their classification and a means to develop a standardized surgical technique for their repair. This study also demonstrates the value of novel biomechanical testing methods in investigating pathological tissues of orthopaedic interest.Cite this article: A. K. Woods, J. Broomfield, P. Monk, F. Vollrath, S. Glyn-Jones. Dynamic shear analysis: a novel method to determine mechanical integrity of normal and torn human acetabular labra: Implications for prediction of outcome of repair. Bone Joint Res 2018;7:440-446. DOI: 10.1302/2046-3758.77.BJR-2017-0282.R2.

Clinical outcomes of arthroscopic repair of acetabular labral tears

Purpose

To evaluate the primary clinical outcomes of arthroscopic labral repair.

Methods

All patients who underwent arthroscopic repair of the acetabular labrum performed by a senior surgeon between October 2010 and December 2013 were invited to participate in this prospective study. Patients included were those who had a preoperative diagnosis of labral tears, a lateral centre edge greater than 25° and a labral tear believed to be suturable during the intraoperative evaluation. Patients with Tönnis grade 2 or grade 3 hip osteoarthritis and those who had undergone a previous hip surgery were excluded. All patients were evaluated using the modified Harris Hip Score (mHHS) during the final appointment before surgery, 4 months after surgery and at the final evaluation. Interviews were conducted by the senior surgeon.

Results

Eighty-four patients (90 hips) underwent arthroscopic repair. The mean age was 44.2 years and the mean follow-up period was 43.0 months (minimum of 25 months and maximum of 59 months). The mean mHHS was 80.4 preoperatively, 95.0 at 4 months postoperatively and 96.6 at final evaluation. A statistically significant difference existed among these scores (p<0.001).

Conclusion

Arthroscopic labral repair was associated with a clinically significant improvement in mHHS after short-term (4 months) and medium-term (43 months) follow-up.

Level of evidence

Level IV, therapeutic case series.

Magnetic Resonance Imaging (MRI) and Hip Arthroscopy Correlations

The hip is a complex joint which commonly generates referrals to orthoaedic surgeons. Hip arthroscopy continues to expand its indications for addressing hip pathology. Before operative intervention, the appropriate information must be obtained with magnetic resonance imaging playing a significant role in the workup given its outstanding characterization of soft tissue anatomy. We attempt to highlight multiple hip findings to correlate intraoperative arthroscopic findings with specific magnetic resonance imaging images and sequences.

Hip arthroscopy in patients less than 25 years of age in the treatment of labral tears: aetiology and clinical outcomes

BACKGROUND

Hip arthroscopy has evolved into a well-established and rapidly growing field of orthopedic surgery for the management of labral tears. The purpose of this study was to review clinical outcomes of patients less than 25 years of age undergoing hip arthroscopy for treatment of a labral tear.

METHODS

From 2005 to 2013, 82 hips in 76 patients with mean age of 20.4 (16-25 range) underwent hip arthroscopy for treatment of labral-chondral damage. The Western Ontario McMaster Universities Osteoarthritis Index (WOMAC) and hip disability and osteoarthritis outcome score (HOOS) were recorded at latest follow-up.

RESULTS

36 of 86 hips (42%) had isolated labral pathology with no associated bony pathology (normal alpha and centre-edge angle; no retroversion). Beck score (intraoperative cartilage damage) of 3 or more was significantly associated with an alpha angle of more than 55 degrees (odds ratio [OR], 3.6; confidence interval [CI], 1.2-11.0) and presence of femeroacetabular impingement (OR, 4.5; CI, 1.3-15.2). HOOS pain, sports/recreation, and quality of life significantly improved from preoperative to one year after surgery (p<0.05). 8 patients had re-operations for persistent pain; 5 underwent arthroscopic labral repair; 2 underwent arthroscopy with subsequent periacetabular osteotomy (PAO); 1 had only a periacetabular osteotomy (PAO). Complications included 2 lateral femoral cutaneous nerve deficits and 1 deep vein thrombosis.

CONCLUSIONS

Labral tears in patients less than 25 years of age occurs commonly without bony deformities, with those with normal head/neck contour demonstrating significantly less early cartilage damage than those with bony pathology. Hip arthroscopy in young patients can improve function and quality of life with minimal morbidity.

Arthroscopic treatment of chondral defects in the hip: AMIC, MACI, microfragmented adipose tissue transplantation (MATT) and other options

Chondral lesions are currently considered in the hip as a consequence of trauma, osteonecrosis, dysplasia, labral tears, loose bodies, dislocation, previous slipped capital femoral epiphysis and Femoro-Acetabular-Impingement (FAI). The management of chondral lesions is debated and several techniques are described. The physical examination must be carefully performed, followed by radiographs and magnetic resonance imaging (MRI). Differential diagnosis with other pathologies must be considered. Debridement is indicated in patients younger than 50 years with a chondropathy of 1st or 2nd degree. Microfractures are indicated in patients younger than 50 years with a chondropathy of 3rd or 4th degree less than 2 cm2. Matrix-Induced Autologous Chondrocyte Implantation (MACI) and Autologous Matrix-Induced Chondrogenesis (AMIC) procedures are indicated in patients with full-thickness symptomatic 3rd-4th degree chondral defects, extended 2 cm2 or more. The AMIC procedure has the advantage of a one-step procedure and much less expense. Microfragmented adipose tissue transplantation (MATT) is indicated for the treatment of delamination and 1st and 2nd degree chondral lesions, regardless of the age of the patient. Chondral defects are effective when the joint space is not compromised. When the Tonnis classification is two or greater, treatment of chondral lesions should be considered ineffective.

Prevalence and clinical significance of hypertrophic labrum in non-dysplastic hips

BACKGROUND

Hypertrophic labrum in dysplastic hip has been frequently reported and is known as limbus in developmental dysplasia of the hip. However, hypertrophic labrum without hip dysplasia has not been reported to date. The purpose of this study was to define hypertrophic labrum and to investigate the prevalence and clinical significance of an abnormally hypertrophic labrum in non-dysplastic hips.

METHODS

Between 2007 and 2014, direct CT arthrography was performed in 464 patients (470 hips) who had chronic groin pain and positive impingement or Faber test. There were 189 male (192 hips) and 275 female (278 hips) patients. The mean age was 46.8 years (range, 16-74 years). The hypertrophic labrum was defined as a labrum wider than two standard deviations away from the mean. Surgical correlation of hypertrophic labrum was obtained in cases with hip arthroscopy by a single surgeon.

RESULTS

Seventeen hips (3.6%) were found to have a hypertrophic labrum which had a mean width of 11.2 mm (±1.1) (range, 9.8-14.1 mm). The average width (±SD) of the labrum without hypertrophy was 5.5 mm (±2.4) (range, 2-9.8 mm). Arthroscopic findings of the hypertrophic labrum included fissure and longitudinal tear at the chondrolabral junction and they were associated with chondral abnormality adjacent to the lesion.

CONCLUSIONS

Hypertrophic labrum without hip dysplasia is not rare with a high incidence of tears. Care should be taken during arthroscopic access to the hip joint in patients with this morphologic variation as iatrogenic damage can occur more easily.

LEVEL OF EVIDENCE

Case Series; Level IV.

The cytokine expression in synovial membrane and the relationship with pain and pathological findings at hip arthroscopy

Background

Synovial membrane inflammation is the most common finding presenting during hip arthroscopy, and may play a role in hip pain. We sought to determine the relationships between synovial cytokine levels, hip pain, and arthroscopic findings of the hip joint.

Methods

We prospectively included 33 patients who underwent arthroscopic hip surgery (34 hips). For all patients, radiographs and severity of pain were evaluated preoperatively. During arthroscopy, we classified the chondral injury and synovitis, noted the incidence of labral tear and its instability, and a sample of the synovial membrane was harvested for quantitative PCR to determine levels of TNFα, IL1β, IL6, ADAMTS4, MMP1, and MMP3. The relationships between the levels of these cytokines, severity of hip pain, and the pathological findings during arthroscopy were examined.

Results

Pain intensity and cytokine levels were not significantly different between patients with labral tear or instability and those without. By contrast, the expression of TNFα, IL1β, IL6, and MMP1 mRNA was significantly higher in patients with diffuse synovitis than in patients with focal synovitis. VAS score during rest showed significant positive correlation with IL6 (r = 0.45, p < 0.01), while VAS score on walking showed a positive correlation with TNFα (r = 0.47, p < 0.01), and ADAMTS4 (r = 0.51, p < 0.01). The modified Harris Hip pain score showed a negative correlation with TNFα (r = −0.38, p = 0.04) and IL6 (r = −0.58, p < 0.01).

Conclusions

The severity of synovitis and chondral injury are considered to be more important in the pathology of hip pain than labral tear or instability. Inflammatory cytokines, especially TNFα and IL6 might play an important role in the pathogenesis of pain in patients indicated for hip arthroscopy, possibly depending on the severity of synovitis.

Defining modes of failure after joint-preserving surgery of the hip

Aims

Joint-preserving surgery of the hip (JPSH) has evolved considerably and now includes a number of procedures, including arthroscopy, surgical dislocation, and redirectional osteotomies of the femur and acetabulum. There are a number of different factors which lead to failure of JPSH. Consequently, it is of interest to assess the various modes of failure in order to continue to identify best practice and the indications for these procedures.

Patients and Methods

Using a retrospective observational study design, we reviewed 1013 patients who had undergone JPSH by a single surgeon between 2005 and 2015. There were 509 men and 504 women with a mean age of 39 years (16 to 78). Of the 1013 operations, 783 were arthroscopies, 122 surgical dislocations, and 108 peri-acetabular osteotomies (PAO). We analysed the overall failure rates and modes of failure. Re-operations were categorised into four groups: Mode 1 was arthritis progression or organ failure leading to total hip arthroplasty (THA); Mode 2 was an Incorrect diagnosis/procedure; Mode 3 resulted from malcorrection of femur (type A), acetabulum (type B), or labrum (type C) and Mode 4 resulted from an unintended consequence of the initial surgical intervention.

Results

At a mean follow-up of 2.5 years, there had been 104 re-operations (10.2%) with a mean patient age of 35.5 years (17 to 64). There were 64 Mode 1 failures (6.3%) at a mean of 3.2 years following JPSH with a mean patient age of 46.8 years (18 to 64). There were 17 Mode 2 failures (1.7%) at a mean of 2.2 years post-JPSH with a mean patient age of 28.9 years (17 to 42) (2% scopes; 1% surgical dislocations). There were 19 Mode 3 failures (1.9%) at a mean of 2.0 years post-JPSH, with a mean patient age of 29.9 years (18 to 51) (2% scopes; 2% surgical dislocations; 5% PAO). There were 4 Mode 4 failures (0.4%) at a mean of 1.8 years post-JPSH with a mean patient age of 31.5 years (15 to 43). Using the modified Dindo-Clavien classification system, the overall complication rate among JPSHs was 4.2%.

Conclusion

While defining the overall re-operation and complication rates, it is important to define the safety and effectiveness of JPSH. Standardisation of the modes of failure may help identify the best practice. Application of these modes to large clinical series, such as registries, will assist in further establishing how to improve the efficacy of JPSH. Cite this article: Bone Joint J 2017;99-B:303–9.

Clinical Outcomes of an Initial 3-month Trial of Conservative Treatment for Femoroacetabular Impingement

BACKGROUND

Femoroacetabular impingement (FAI) can be managed either conservatively or by a surgical correction of the deformity causing impingement. However, there is insufficient evidence to justify an immediate surgical treatment in all symptomatic patients, and the role of a nonoperative treatment is unclear. This study evaluates the role of conservative treatment for FAI.

MATERIALS AND METHODS

87 patients (102 hips) diagnosed as FAI between January 2011 and May 2012 were included in this retrospective study. All patients underwent an initial 3-month conservative treatment followed by arthroscopic hip surgery if symptoms did not improve. Clinical outcome scores (modified Harris Hip Score, nonarthritic hip score, and Western Ontario and McMaster Universities Arthritis Index) were evaluated at baseline and at the end of followup, and scores were compared between the nonsurgical and surgical groups.

RESULTS

The final analysis included 83 patients (55 men, 28 women; 97 hips) because four patients were lost to followup. The average age was 45.1 years and 14 patients had bilateral symptomatic FAI. After an initial conservative treatment averaging 27.5 months (range 24-36 months), 53 hips (54.6%) could perform normal daily activities. The nonsurgical group had significant improvements in all clinical scores at the end of followup (P < 0.001). Forty four hips (45.4%) were unresponsive to conservative treatment and underwent arthroscopic hip surgery with subsequent significant improvements in clinical scores (P < 0.001). At the end of followup, there were no significant differences in clinical scores between the two groups.

CONCLUSION

An initial trial of conservative treatment of sufficient length should be considered for FAI patients before surgical intervention.

A retrospective analysis on the correlation between hip pain, physical examination findings, and alpha angle on MR images

BACKGROUND

We aimed to search whether alpha angle, a radiological clue used in the diagnosis of femoroacetabular impingement, is correlated with the presence of hip pain, internal rotation angle, and impingement test results on hip impingement patients (CAM type).

METHODS

Medical records of 334 patients (156 women, 178 men) with an average age of 33.8 ± 8.4 (range 20-50) years were retrospectively studied for the alpha angle of the hip measured on magnetic resonance images (MRI). Hip pain and internal rotation angles as well as results of impingement tests were reviewed.

RESULTS

Hip pain was reported more frequently on the right side (n = 35, 10.5%) compared to the left side (n = 22, 6.6%) (p = 0.047). No difference was observed between the right and left sides regarding alpha angles (p = 0.145), internal rotation angles (p = 0.637), or positivity of impingement test (p = 0.210). Internal rotation angles were significantly higher in cases without hip pain (p < 0.001) and in patients with negative impingement test result (p < 0.001). Internal rotation angle correlated positively with age and negatively with the alpha angle. Alpha angle was increased in cases that report pain, those with an internal rotation angle <20°, or cases with positive impingement test. The pain was more common, internal rotation angle was higher, and positivity for impingement was more frequent if the alpha angle was <55°. Patients with hip pain or positive impingement test or internal rotation angle <20° had increased alpha angles (p < 0.001).

CONCLUSIONS

The pain, impingement test results, and internal rotation angle seem to be associated with alpha angle of the hip measured on MRI in hip impingement patients.

Hip Pain After a Femoral Fracture: It Is Not Always Related to the Implant

The source of continued hip pain following fixation of traumatic femoral shaft fracture is not always clear. Intra-articular hip pathology is often overlooked when evaluating the etiology of residual pain. The purpose of this study was to describe cases of intra-articular hip pathology following traumatic femoral shaft fracture. This was a retrospective case series of patients presenting to a private practice orthopedic clinic from 2012 to 2015. Three patients presented with symptomatic intra-articular hip pathology following traumatic ipsilateral femoral shaft fracture. Patients who underwent hip arthroscopy with allograft labral reconstruction were identified retrospectively. Validated, subjective outcome scores administered included the Modified Harris Hip Score (MHHS), Lower Extremity Functional Scale (LEFS), visual analog scale (VAS) for pain, and VAS scale for patient satisfaction. Three patients were identified with residual, disabling groin pain after femoral shaft fracture fixation following a traumatic motor vehicle accident. All 3 patients were found to have a symptomatic ipsilateral labral tear. In 2 of the patients, an indentation on the lateral femoral head was appreciated, which was hypothesized to be caused by a subluxation event. All 3 patients were treated with arthroscopic hip surgery. At final follow-up, all 3 patients showed significant improvement in MHHS, VAS pain scores, level of satisfaction, and LEFS. Residual pain following ipsilateral femoral shaft fracture is not always related to implant. Intra-articular hip pathology should be considered in patients with lingering hip pain. [Orthopedics. 2016; 39(6):e1080-e1084.].

Quantification and correlation of hip capsular volume to demographic and radiographic predictors

PURPOSE

The purpose of this study was to develop a novel method to quantify hip capsular volume in patients undergoing hip arthroscopic surgery, utilizing magnetic resonance arthrogram (MRA) and to determine whether there are demographic or radiological factors that are associated with capsular volume.

METHODS

A retrospective review was performed from 2006 to 2014 of consecutive patients who presented with hip pain and received a hip MRA and plain radiographs. All patients were suspected of soft tissue injury due to underlying femoroacetabular impingement (FAI). A novel technique using Osirix MD for the quantification of capsular and femoral head volumes was described.

RESULTS

Ninety-seven patients met the study criteria and were included for analysis. The average total capsular volume (including the femoral head) measured 79.89 ± 20.35 cm(3), average femoral head volume 46.68 ± 12.32 cm(3), and average true capsular volume measured 33.20 ± 12.58 cm(3). Average total capsular:femoral head volume ratio was 1.74 ± 0.27. Significant differences were seen between genders for total capsular volume (P < 0.01), femoral head volume (P < 0.01), and true capsular volume (P < 0.01). Total capsular volume:femoral head ratio was greater for females, but was not statistically significant (n.s.). Femoral head volume significantly correlated with alpha angle (P < 0.01), height (P < 0.01), BMI (P < 0.01), BMI (P = 0.02), and age (P < 0.01). Total capsular volume significantly correlated with height (P < 0.01), BMI (P = 0.01), and age (P < 0.01). Age was also correlated with true capsular volume (P = 0.011). No significant differences in capsular volumes were found between normal and abnormal radiographic measurements.

CONCLUSION

The current study describes a reproducible radiographic measurement for hip capsule volumes from MRAs. Only gender was predictive of total capsular volume, femoral head volume, and true capsular volume. There were no macroscopic anatomical differences evident on MRA. This method showed good intra- and inter-observer reliability and can aid in future research regarding hip capsule volumes. This novel technique may potentially allow clinicians a readily available and reliable method to detect large and redundant capsules, a possible predisposition for hip micro-instability.

LEVEL OF EVIDENCE

Retrospective case series, Level IV.

Prevalence of acetabular labral tears in asymptomatic children

PURPOSE

Magnetic resonance imaging (MRI) is a sensitive, non-invasive modality to diagnose acetabular labral pathology, and the normal variants of the acetabular labrum have been characterized in adults. However, the prevalence of labral pathology in the asymptomatic pediatric population is unknown.

METHODS

All pelvic MRIs performed at a large tertiary-care children's hospital were reviewed during one calendar year (2014). Only patients aged between 2 and 18 years were included, and scans were excluded for hip pain/pathology or technical inadequacy. A blinded pediatric musculoskeletal radiologist read all eligible scans for the presence or absence of a labral tear.

RESULTS

Three hundred and ninety-four pelvic MRIs were screened, and patients were excluded for hip pain/pathology (85 subjects), or technical inadequacy (190 subjects). One hundred and eight subjects (216 hips) met the inclusion criteria and were technically adequate for analysis. Labral tears were visualized in three of 216 (1.4 %) hips (two of the 110 subjects; 1.9 %).

CONCLUSIONS

There is a low rate of asymptomatic labral pathology by MRI in pediatric patients. The clinical history remains the means of differentiating real labral pathology from spurious imaging findings.

LEVEL OF EVIDENCE IV

Case series (prevalence).

Open-MRI measures of cam intrusion for hips in an anterior impingement position relate to acetabular contact force

Open MRI in functional positions has potential to directly and non-invasively assess cam femoroacetabular impingement (FAI). Our objective was to investigate whether open MRI can depict intrusion of the cam deformity into the intra-articular joint space, and whether intrusion is associated with elevated acetabular contact force. Cadaver hips (9 cam; 3 controls) were positioned in an anterior impingement posture and imaged using open MRI with multi-planar reformatting. The β-angle (describing clearance between the femoral neck and acetabulum) was measured around the entire circumference of the femoral neck. We defined a binary "MRI cam-intrusion sign" (positive if β < 0°). We then instrumented each hip with a piezoresistive sensor and conducted six repeated positioning trials, measuring acetabular contact force (F). We defined a binary "contact-force sign" (positive if F > 20N). Cam hips were more likely than controls to have both a positive MRI cam-intrusion sign (p = 0.0182, Fisher's exact test) and positive contact-force sign (p = 0.0083), which represents direct experimental evidence for cam intrusion. There was also a relationship between the MRI cam-intrusion sign and contact-force sign (p = 0.033), representing a link between imaging and mechanics. Our findings indicate that open MRI has significant potential for in vivo investigation of the cam FAI mechanism.

Clinical and radiographical results of labral reconstruction

Treatment of femoroacetabular impingement (FAI) includes correction of underlying bony deformities. Labrum preservation is recommended whenever possible. In hips, where the labrum is missing or damaged beyond preservation, labral reconstruction is an option to restore labral seal. Between 2008 and 2011, 84 hips underwent treatment for FAI by means of a surgical hip dislocation. In 13 of these hips (11 patients), the severely damaged or missing labrum was reconstructed with ligamentum capitis femoris. Pre- and postoperative radiographic and clinical data were analysed with a mean follow-up of 38 months (range: 19–65 months). Clinical outcome was determined with Oxford hip score (OHS) and overall satisfaction, rest and load pain with a visual analogue scale (VAS; 0–100). Clinical outcome was compared with a control group where labral refixation was performed. Mean OHS improved significantly (P ≤ 0.001) from 29 (SD 8) to 44 (SD 4). Overall satisfaction with the hip increased significantly (P = 0.002) from 44 (SD 35) to 87 (SD 15). Mean VAS for rest pain decreased significantly (P = 0.0004) from 45 (SD 35) to 5 (SD 7) as well as for load pain (P = 0.0007) from 59 (SD 26) to 16 (SD 19). There were no significant differences between the two groups. Reconstruction of the acetabular labrum with ligamentum capitis femoris yields good clinical results. Technical superiority of open labral reconstruction may explain the unexpected, excellent outcome.

Effect of centre-edge angle on clinical and quality of life outcomes after arthroscopic acetabular labral debridement

PURPOSE

The aim of this study was to compare clinical and quality of life outcomes following arthroscopic acetabular labral debridement between patients with different centre-edge (CE) angle.

METHODS

A total of 79 patients who underwent hip labral debridement were enrolled in this study. Radiographic measurements of CE angle were collected, and patients were assigned into a normal group (25° < CE angle <40°, n = 68) and dysplasia group (CE angle <20°, n = 11). Clinical outcomes were evaluated by modified Harris Hip Score (mHHS), Hip Outcome Score (HOS) for activities of daily living (ADL) and sports and Short Form 12 (SF-12).

RESULTS

At the final follow-up, the normal group showed significant improvements in mHHS, HOS (ADL and sports) and SF-12 (P < 0.05). However, the dysplasia group revealed significant improvements in mHHS, HOS (ADL) and SF-12 physical component summary (PCS) (P < 0.05) and no significant changes in HOS sports and SF-12 mental component summary (MCS) (P > 0.05). Additionally, there was a greater improvement in clinical scores post-operatively in the normal group compared with the dysplasia group (P < 0.05).

CONCLUSIONS

Arthroscopic acetabular labral debridement resulted in significantly greater clinical and quality of life outcomes in patients with CE angle >25° compared with patients with CE angle < 20°.

The prevalence of acetabular labral tears and associated pathology in a young asymptomatic population

Acetabular labral tears and associated intra-articular pathology of the hip have been recognised as a source of symptoms. However, it is now appreciated that there is a relatively high prevalence of asymptomatic labral tears. In this study, 70 young asymptomatic adult volunteers with a mean age of 26 years (19 to 41) were recruited and underwent three tesla non-arthrographic MR scans. There were 47 women (67.1%) and 23 men (32.9%). Labral tears were found in 27 volunteers (38.6%); these were an isolated finding in 16 (22.9%) and were associated with other intra-articular pathology in the remaining 11 (15.7%) volunteers. Furthermore, five (7.1%) had intra-articular pathology without an associated labral tear. Given the high prevalence of labral pathology in the asymptomatic population, it is important to confirm that a patient's symptoms are due to the demonstrated abnormalities when considering surgery.

Differences in Lower Extremity and Trunk Kinematics between Single Leg Squat and Step Down Tasks

The single leg squat and single leg step down are two commonly used functional tasks to assess movement patterns. It is unknown how kinematics compare between these tasks. The purpose of this study was to identify kinematic differences in the lower extremity, pelvis and trunk between the single leg squat and the step down. Fourteen healthy individuals participated in this research and performed the functional tasks while kinematic data were collected for the trunk, pelvis, and lower extremities using a motion capture system. For the single leg squat task, the participant was instructed to squat as low as possible. For the step down task, the participant was instructed to stand on top of a box, slowly lower him/herself until the non-stance heel touched the ground, and return to standing. This was done from two different heights (16cm and 24cm). The kinematics were evaluated at peak knee flexion as well as at 60° of knee flexion. Pearson correlation coefficients (r) between the angles at those two time points were also calculated to better understand the relationship between each task. The tasks resulted in kinematics differences at the knee, hip, pelvis, and trunk at both time points. The single leg squat was performed with less hip adduction (p ≤ 0.003), but more hip external rotation and knee abduction (p ≤ 0.030), than the step down tasks at 60° of knee flexion. These differences were maintained at peak knee flexion except hip external rotation was only significant in the 24cm step down task (p ≤ 0.029). While there were multiple differences between the two step heights at peak knee flexion, the only difference at 60° of knee flexion was in trunk flexion (p < 0.001). Angles at the knee and hip had a moderate to excellent correlation (r = 0.51–0.98), but less consistently so at the pelvis and trunk (r = 0.21–0.96). The differences in movement patterns between the single leg squat and the step down should be considered when selecting a single leg task for evaluation or treatment. The high correlation of knee and hip angles between the three tasks indicates that similar information about knee and hip kinematics was gained from each of these tasks, while pelvis and trunk angles were less well predicted.

Acetabular paralabral cyst: an unusual cause of femoral vein compression

Acetabular labral tears are a known cause of hip pain in the young, active patient. Labral tears can be due to trauma, femoroacetabular impingement, capsular laxity, dysplasia, and degenerative pathology. Paralabral cysts are relatively common in association with labral tears of the hip, with cysts seen on magnetic resonance imaging studies in as many as 50% to 70% of patients with labral tears. In some cases the cysts can become sizeable and cause neurovascular compression. Nonoperative interventions for the management of paralabral cysts in the shoulder and knee have shown high recurrence rates. In the shoulder and knee, arthroscopic debridement of paralabral cysts has shown good results with lower recurrence rates and resolution of neurovascular function. In the hip there is limited literature regarding surgical management of paralabral cysts. We present a surgical technique for arthroscopic decompression of acetabular paralabral cysts combined with labral repair.

Labral and cartilage abnormalities in young patients with hip pain: accuracy of 3-Tesla indirect MR arthrography

OBJECTIVE

Assess the diagnostic accuracy of 3-T indirect magnetic resonance arthrography (iMRA) for hip cartilage and labral pathology detection using arthroscopy as the reference standard and compare it to the published performance of direct magnetic resonance arthrography (dMRA).

MATERIALS AND METHODS

Between 2009 and 2011, 290 patients suspected of having femoroacetabular impingement underwent iMRA. Our study group consisted of 41 of these patients (17 males, mean age 35 years; 24 females, mean age 33 years) who did not have a prior history of hip surgery and who subsequently underwent arthroscopy. Two experienced musculoskeletal radiologists separately evaluated the randomized and anonymized studies for the presence and quadrant location of labral and cartilage pathology. These recorded data were compared to arthroscopic reports.

RESULTS

Forty-one patients had labral pathology, 34 patients had acetabular and 5 patients had femoral cartilage pathology at arthroscopy. Sensitivity, specificity, accuracy, negative- and positive-predictive values for labral lesion detection were respectively 98, 99, 99, 99 and 98 %; for acetabular cartilage lesion detection they were 69, 98, 89, 87 and 95 %; for femoral cartilage lesion detection they were 69, 95, 93 and 39 %. Sensitivities of iMRA by quadrant (anteroinferior, anterosuperior, posteroinferior, posterosuperior) for the labrum were 100.0, 95.0, NA and 85.7 %, for acetabular cartilage were NA, 58.8, NA and 39.5 % and for femoral cartilage were 50.0, 33.3, 75.0 and 75.0 %). NA indicates results not available because of the absence of findings in those quadrants. Specificities of iMRA by quadrant (anteroinferior, anterosuperior, posteroinferior, posterosuperior) for the labrum (95.0, 100.0, 95.1, 67.5 %), acetabular (100.0, 85.7, 92.6, 79.5 %) and femoral cartilage (100.0, 94.7, 96.2, 85.9 %).

CONCLUSION

iMRA at 3 T is accurate in detecting labral pathology suggesting that it is a viable alternative to dMRA.

Subject-specific patterns of femur-labrum contact are complex and vary in asymptomatic hips and hips with femoroacetabular impingement

BACKGROUND

Femoroacetabular impingement (FAI) may constrain hip articulation and cause chondrolabral damage, but to our knowledge, in vivo articulation and femur-labrum contact patterns have not been quantified.

PURPOSE

In this exploratory study, we describe the use of high-speed dual-fluoroscopy and model-based tracking to dynamically measure in vivo hip articulation and estimate the location of femur-labrum contact in six asymptomatic hips and three hips with FAI during the impingement examination. We asked: (1) Does femur-labrum contact occur at the terminal position of impingement? (2) Could range of motion (ROM) during the impingement examination appear decreased in hips with FAI? (3) Does the location of femur-labrum contact coincide with that of minimum bone-to-bone distance? (4) In the patients with FAI, does the location of femur-labrum contact qualitatively correspond to the location of damage observed intraoperatively?

METHODS

High-speed dual-fluoroscopy images were acquired continuously as the impingement examination was performed. CT arthrogram images of all subjects were segmented to generate three-dimensional (3-D) surfaces for the pelvis, femur, and labrum. Model-based tracking of the fluoroscopy images enabled dynamic kinematic observation of the 3-D surfaces. At the terminal position of the examination, the region of minimal bone-to-bone distance was compared with the estimated location of femur-labrum contact. Each patient with FAI underwent hip arthroscopy; the location of femur-labrum contact was compared qualitatively with damage found during surgery. As an exploratory study, statistics were not performed.

RESULTS

Femur-labrum contact was observed in both groups, but patterns of contact were subject-specific. At the terminal position of the impingement examination, internal rotation and adduction angles for each of the patients with FAI were less than the 95% confidence intervals (CIs) for the asymptomatic control subjects. The location of minimum bone-to-bone distance agreed with the region of femur-labrum contact in two of nine hips. The locations of chondrolabral damage identified during surgery qualitatively coincided with the region of femur-labrum contact.

CONCLUSIONS

Dual-fluoroscopy and model-based tracking provided the ability to assess hip kinematics in vivo during the entire impingement examination. The high variability in observed labrum-femur contact patterns at the terminal position of the examination provides evidence that subtle anatomic features could dictate underlying hip biomechanics. Although femur-labrum contact occurs in asymptomatic and symptomatic hips at the terminal position of the impingement examination, contact may occur at reduced adduction and internal rotation in patients with FAI. Use of minimum bone-to-bone distance may not appropriately identify the region of femur-labrum contact. Additional research, using a larger cohort and appropriate statistical tests, is required to confirm the findings of this exploratory study.

Asymptomatic hip/groin pathology identified on magnetic resonance imaging of professional hockey players: outcomes and playing status at 4 years' follow-up

PURPOSE

The purpose of this study was to evaluate the clinical outcomes and playing status of professional hockey players 4 years after they underwent bilateral magnetic resonance imaging (MRI) of asymptomatic hips.

METHODS

Twenty-one professional hockey players with no previous hip/groin pain underwent hip/pelvis MRI. Each MRI study was evaluated by 3 subspecialty-trained musculoskeletal radiologists for alpha-angle measurement and the presence of adductor-abdominal rectus abnormalities, acetabular labral tears, osteochondral lesions of the femoral head or acetabulum, hip effusion, adjacent muscle contusions or strain injury, and stress fractures. The MRI findings of the players were previously published. In the present study, each athlete was followed up by (1) completion of a questionnaire assessing hip/groin dysfunction at 1 and 2 years' follow-up and (2) number of games played over the course of the next 4 years. A significant difference in the number of games played was considered when a player missed more than 5 games compared with the index year.

RESULTS

We enrolled 21 players in the study. Of these players, 4 had no abnormality bilaterally, 10 had muscle strain and/or tendinosis in 1 or both hips, and 15 had labral tears identified in 1 or both hips. Eight players had a combination of labral tears and muscle strain/tendinosis. Of 21 professional hockey players, 16 (76%) and 14 (67%) were available at 1 and 2 years' follow-up, respectively. Nineteen of 21 players (90%) continued to play professional hockey at 4 years' follow-up. The development of any hip and/or pelvis symptoms occurred in only 3 players (14%) within 4 years. Only 1 of the 3 players missed any games because of hip and/or pelvis symptoms. The affected player missed several games because of proximal iliotibial band symptoms that occurred in the third year after MRI.

CONCLUSIONS

Hip/pelvis pathology is commonly uncovered on MRI of asymptomatic hockey players; however, this pathology does not produce symptoms or result in missed games within 4 years in most players.

LEVEL OF EVIDENCE

Level IV, therapeutic case series.

MRI of the hip for the evaluation of femoroacetabular impingement; past, present, and future

The concept of femoroacetabular impingement (FAI) has, in a relatively short time, come to the forefront of orthopedic imaging. In just a few short years MRI findings that were in the past ascribed to degenerative change, normal variation, or other pathologies must now be described and included in radiology reports, as they have been shown, or are suspected to be related to, FAI. Crucial questions have come up in this time, including: what is the relationship of bony morphology to subsequent cartilage and labral damage, and most importantly, how is this morphology related to the development of osteoarthritis? In this review, we attempt to place a historical perspective on the controversy, provide guidelines for interpretation of MRI examinations of patients with suspected FAI, and offer a glimpse into the future of MRI of this complex condition.

Diagnosing Femoroacetabular Impingement From Plain Radiographs: Do Radiologists and Orthopaedic Surgeons Differ?

Background:

A diagnosis of femoroacetabular impingement (FAI) requires careful history and physical examination, as well as an accurate and reliable radiologic evaluation using plain radiographs as a screening modality. Radiographic markers in the diagnosis of FAI are numerous and not fully validated. In particular, reliability in their assessment across health care providers is unclear.

Purpose:

To determine inter- and intraobserver reliability between orthopaedic surgeons and musculoskeletal radiologists.

Study Design:

Cohort study (diagnosis); Level of evidence, 3.

Methods:

Six physicians (3 orthopaedic surgeons, 3 musculoskeletal radiologists) independently evaluated a broad spectrum of FAI pathologies across 51 hip radiographs on 2 occasions separated by at least 4 weeks. Reviewers used 8 common criteria to diagnose FAI, including (1) pistol-grip deformity, (2) size of alpha angle, (3) femoral head-neck offset, (4) posterior wall sign abnormality, (5) ischial spine sign abnormality, (6) coxa profunda abnormality, (7) crossover sign abnormality, and (8) acetabular protrusion. Agreement was calculated using the intraclass correlation coefficient (ICC).

Results:

When establishing an FAI diagnosis, there was poor interobserver reliability between the surgeons and radiologists (ICC batch 1 = 0.33; ICC batch 2 = 0.15). In contrast, there was higher interobserver reliability within each specialty, ranging from fair to good (surgeons: ICC batch 1 = 0.72; ICC batch 2 = 0.70 vs radiologists: ICC batch 1 = 0.59; ICC batch 2 = 0.74). Orthopaedic surgeons had the highest interobserver reliability when identifying pistol-grip deformities (ICC = 0.81) or abnormal alpha angles (ICC = 0.81). Similarly, radiologists had the highest agreement for detecting pistol-grip deformities (ICC = 0.75).

Conclusion:

These results suggest that surgeons and radiologists agree among themselves, but there is a need to improve the reliability of radiographic interpretations for FAI between the 2 specialties. The observed degree of low reliability may ultimately lead to missed, delayed, or inappropriate treatments for patients with symptomatic FAI.

Patient satisfaction after arthroscopic repair of acetabular labral tears

Background

Acetabular labral tear is a main cause of hip pain and disability, often requiring surgical treatment. Improvements of hip arthroscopic technique have produced positive outcomes after labral repair with arthroscopy. The purpose of this study was to determine clinical outcomes and patient satisfaction after arthroscopic repair of acetabular labral tear.

Methods

We interviewed 21 patients (10 men and 11 women; mean age, 36 years [range, 22 to 57 years]) with acetabular labral tears that had been repaired arthroscopically in terms of satisfaction of the procedure. In addition, clinical outcome was assessed using visual analog scale (VAS) score, University of California, Los Angeles (UCLA) activity, Western Ontario and McMaster Universities (WOMAC) osteoarthritis index, and Harris hip score, and radiologic outcome was assessed using serial radiography. The patients were followed for 24-50 months.

Results

The mean Harris hip score was 73 points (range, 64 to 84 points) preoperatively and 83 points (range, 66 to 95 points) postoperatively. Fifteen hips (71%) were rated excellent and good. The mean WOMAC osteoarthritis index and VAS scores were improved at final follow-up. UCLA activity at the latest follow-up improved in 16 patients. The Tonnis grade of osteoarthritis at the latest follow-up did not change in all patients. Eighteen of the patients (86%) were satisfied with the procedure.

Conclusions

High rate of satisfaction after arthroscopic repair of acetabular labral tears is an encouraging outcome. Arthroscopic treatment of labral tears might be a useful technique in patients with hip pathologies, such as femoroacetabular impingement with labral tears.

Incidence of hip pain in a prospective cohort of asymptomatic volunteers: is the cam deformity a risk factor for hip pain?

BACKGROUND

Although cam-type femoroacetabular impingement is commonly associated with labral chondral damage and hip pain, a large proportion of asymptomatic individuals will have this deformity.

PURPOSE

To determine the incidence of hip pain in a prospective cohort of volunteers who had undergone magnetic resonance imaging (MRI) of their hips.

STUDY DESIGN

Case control study; Level of evidence, 3.

METHODS

A total of 200 asymptomatic volunteers who underwent an MRI of both hips were followed for a mean time of 4.4 years (range, 4.01-4.95 years). Thirty were lost to follow-up, leaving 170 individuals (77 males, 93 females) with a mean age of 29.5 years (range, 25.7-54.5 years). All patients were blinded to the results of their MRI. All completed a follow-up questionnaire inquiring about the presence of hip pain or a history of hip pain lasting longer than 6 weeks since the original MRI. Each patient was asked to draw where the pain was on a body diagram.

RESULTS

Eleven patients (5 males, 6 females; 6.5% of sample; mean age, 29.9 years; range, 25.7-45.6 years) reported hip pain, of which 3 (1 male, 2 females) had bilateral pain for a total of 14 hips. Seven of the 14 painful hips had a cam-type deformity at the time of the initial MRI versus 37 of the 318 nonpainful hips (P = .0002). This gave a relative risk of 4.3 (95% confidence interval [CI], 2.3-7.8) of developing hip pain if cam deformity was present. Those 14 painful hips had a significantly greater alpha angle at the radial 1:30 clock position than did those who did not develop pain with a cam deformity: 61.5° (range, 57.3°-65.7°) versus 57.9° (range, 56.9°-59.1°), respectively (P = .05). A significantly greater proportion of patients (12%) with limited internal rotation ≤20° (versus 2.7% with internal rotation >20°) went on to develop hip pain (P = .009; relative risk = 3.1 [95% CI, 1.6-6.0]).

CONCLUSION

The presence of a cam deformity represents a significant risk factor for the development of hip pain. An elevated alpha angle at the 1:30 clock position and decreased internal rotation are associated with an increased risk of developing hip pain. However, not all patients with a cam deformity develop hip pain, and further research is needed to better define those at greater risk of developing degenerative symptoms.

Debridement versus re-attachment of acetabular labral tears

We have reviewed the current literature to compare the results of surgery aimed to repair or debride a damaged acetabular labrum. We identified 28 studies to be included in the review containing a total of 1631 hips in 1609 patients. Of these studies 12 reported a mean rate of good results of 82% (from 67% to 100%) for labral debridement. Of the 16 studies that reported a combination of debridement and re-attachment, five reported a comparative outcome for the two methods, four reported better results with re-attachment and one study did not find any significant difference in outcomes. Due to the heterogeneity of the studies it was not possible to perform a meta-analysis or draw accurate conclusions. Confounding factors in the studies include selection bias, use of historical controls and high rates of loss of follow-up.

It seems logical to repair an unstable tear in a good quality labrum with good potential to heal in order potentially to preserve its physiological function. A degenerative labrum on the other hand may be the source of discomfort and its preservation may result in persistent pain and the added risk of failure of re-attachment. The results of the present study do not support routine refixation for all labral tears.

Cite this article: Bone Joint J 2014;96-B:24–30.

Femoroacetabular impingement: fact, fiction, or fantasy?

OBJECTIVE

Proponents of femoroacetabular impingement (FAI) now claim that FAI is an important risk factor for hip osteoarthritis and argue that early, aggressive treatment is indicated to stave off long-term complications. The result is more young patients undergoing corrective surgery; does the literature support these claims or has hype trumped reality? This article critically reviews these assertions together with the current scientific evidence that defends (or refutes) them.

CONCLUSION

Each reader will need to weigh the evidence carefully when interpreting images or planning management for patients with possible FAI.

Correlation of magnetic resonance arthrography with revision hip arthroscopy

BACKGROUND

Arthroscopic approaches for the diagnosis and treatment of hip disorders are well established; however, there are limited data regarding revision hip arthroscopy. There have been several studies evaluating the findings of MR arthrography with primary hip arthroscopy, but to our knowledge, no study has evaluated the diagnostic value of MR arthrography before revision hip arthroscopy.

QUESTIONS/PURPOSES

We obtained sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of MR arthrography to detect labral lesions, chondral lesions and loose bodies before revision hip arthroscopy.

METHODS

We performed a single-surgeon, retrospective review of 70 revision hip arthroscopies (62 patients) and assessed the association between MR arthrography findings and intraoperative findings. There were 43 females and 19 males with a mean age of 36 years (range, 17-59 years). Radiographic interpretation was performed by one of four fellowship-trained musculoskeletal radiologists at three institutions, who had at least 5 years of experience. Radiographic findings were compared with surgical findings by one of the authors for calculation of sensitivity, specificity, PPV, and NPV.

RESULTS

The sensitivity, specificity, PPV, and NPV of MR arthrography for detecting labral tears were 82%, 70%, 94%, and 39%, respectively. The sensitivity, specificity, PPV, and NPV of MR arthrography for detecting chondral damage were 65%, 90%, 94%, and 50%, respectively. The sensitivity, specificity, PPV, and NPV of MR arthrography for detecting loose bodies were 33%, 100%, 100%, and 88%, respectively.

CONCLUSIONS

Our study showed the utility of MR arthrography to assist in the diagnosis and treatment of patients with ongoing or recurrent symptoms who have had prior hip arthroscopy. Our data show that MR arthrography is superior at ruling in, rather than ruling out, labral lesions, chondral lesions, and loose bodies, as there were studies interpreted as normal which in fact showed disorders.

Magnetic resonance arthrography for labral tears and chondral wear in femoroacetabular impingement

Magnetic resonance arthrography (MRA) is a useful pre-operative investigation for patients with clinical signs and symptoms of femoroacetabular impingement. Our aim was to assess the diagnostic accuracy of MRA in detecting labral tears and chondral wear in this context. Sixty nine hips were included in the study after exclusions. All patients underwent pre-operative MRA and then subsequent hip arthroscopy. The findings at MRA were compared to those found intraoperatively. For labral tears, sensitivity, specificity and accuracy were 81%, 51% and 58% respectively. For chondral wear these figures were 17%, 100%, and 55% respectively. In our institution, MRA was therefore not as accurate as previously published work suggests.

The hip antero-superior labral tear with avulsion of rectus femoris (HALTAR) lesion: does the SLAP equivalent in the hip exist?

BACKGROUND

The purpose of this report is to describe a new lesion, the "Hip Antero-superior Labral Tear with Avulsion of Rectus femoris (HALTAR)". This injury may be seen in both adolescent and skeletally mature athletes and shares several characteristics with the "Superior Labral tear from Anterior to Posterior (SLAP)" lesion in the shoulder.

METHODS

We present a case example, as well as a detailed anatomic description of the pathological condition.

RESULTS

As the rectus femoris crosses two joints it is exposed to substantial forces during muscle contraction. Considering the peri-articular origin of the reflected head at the superior aspect of the acetabular rim, a powerful eccentric contraction of the rectus femoris muscle or traction related to sudden knee flexion may cause an avulsion injury of the rectus femoris as well as a concomitant labral tear.

CONCLUSIONS

A strain injury of the rectus femoris muscle, which is common in young athletic patients, may cause a concomitant tear of the acetabular labrum. Therefore, we recommend further diagnostic work-up in cases with prolonged hip pain and impaired hip function following an AIIS injury in order to identify any associated peri- and intra-articular damage. In our experience these patients seldom need aggressive surgical management.