Modern Hip Arthroscopy for FAIS May Delay the Natural History of Osteoarthritis in 25% of Patients: A 12-Year Follow-up Analysis

BACKGROUND

Little is known about the effect of modern hip arthroscopy on the natural history of femoroacetabular impingement syndrome (FAIS) with respect to joint preservation.

PURPOSE

To (1) characterize the natural history of FAIS and (2) understand the effect of modern hip arthroscopy by radiographically comparing the hips of patients who underwent only unilateral primary hip arthroscopy with a minimum follow-up of 10 years.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

Between 2010 and 2012, 619 consecutive patients were reviewed from the practice of a single fellowship-trained hip arthroscopic surgeon. Inclusion criteria were FAIS, bilateral radiographic findings of femoroacetabular impingement, primary unilateral hip arthroscopy (labral repair, femoroplasty, or capsular closure), and minimum 10-year follow-up. The preoperative and minimum 10-year postoperative radiographs of patients were evaluated at each time point. Both operative and nonoperative hips were graded using the Tönnis classification or the presence of hip arthroplasty by 2 independent reviewers. Subgroup analyses were performed.

RESULTS

A total of 200 hips from 100 patients were evaluated at a mean follow-up of 12.0 years. Preoperatively, 98% and 99% of operative and nonoperative hips were evaluated as Tönnis grades 0 and 1, respectively; 5% of nonoperative hips had worse Tönnis grades than operative hips. The nonoperative hip advanced to a worse Tönnis grade in 48% (48/100) of cases compared with 28% (28/100) among operative hips. At follow-up, Tönnis grades between hips were equal in 70% (70/100) of the cases, the operative hip had a better grade 25% (25/100) of the time, and the nonoperative hip had a better grade 5% (5/100) of the time. Modern hip arthroscopy was associated with a relative risk reduction of 42% in osteoarthritis progression. Impingement with borderline dysplasia, age, preoperative Tönnis grade, and alpha angle >65° were key risk factors in the radiographic progression of osteoarthritis.

CONCLUSION

Although the majority of patients (70%) undergoing hip arthroscopy for FAIS did not experience differences between operative and nonoperative hips in terms of the radiographic progression of osteoarthritis, the natural history may be favorably altered for 25% of patients whose Tönnis grade was better after undergoing arthroscopic correction. Modern hip arthroscopy indications and techniques represent a valid joint-preservation procedure conferring a relative risk reduction of 42% in the progression of osteoarthritis. Arthroscopy for mixed patterns of impingement and instability were the fastest to degenerate.

Association Between Chondrolabral Junction Breakdown and Conversion to Total Hip Arthroplasty After Hip Arthroscopy for Symptomatic Labral Tears: Minimum 8-Year Follow-up

BACKGROUND

Arthroscopic treatment of femoroacetabular impingement (FAI) and symptomatic labral tears confers short- to midterm benefits, yet further long-term evidence is needed. Moreover, despite the physiological and biomechanical significance of the chondrolabral junction (CLJ), the clinical implications of damage to this transition zone remain understudied.

PURPOSE

To (1) report minimum 8-year survivorship and patient-reported outcome measures after hip arthroscopy for FAI and (2) characterize associations between outcomes and patient characteristics (age, body mass index, sex), pathological parameters (Tönnis angle, alpha angle, type of FAI, CLJ breakdown), and procedures performed (labral management, FAI treatment, microfracture).

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

This retrospective cohort study included patients who underwent primary hip arthroscopy for symptomatic labral tears secondary to FAI by a single surgeon between 2002 and 2013. All patients were ≥18 years of age with minimum 8-year follow-up and available preoperative radiographs. The primary outcome was conversion to total hip arthroplasty (THA), and secondary outcomes included revision arthroscopy, patient-reported outcome measures, and patient satisfaction. CLJ breakdown was assessed using the Beck classification. Kaplan-Meier estimates and weighted Cox regression were used to estimate 10-year survivorship (no conversion to THA) and identify risk factors associated with THA conversion.

RESULTS

In this study of 174 hips (50.6% female; mean age, 37.8 ± 11.2 years) with mean follow-up of 11.1 ± 2.5 years, the 10-year survivorship rate was 81.6% (95% CI, 75.9%-87.7%). Conversion to THA occurred at a mean 4.7 ± 3.8 years postoperatively. Unadjusted analyses revealed several variables significantly associated with THA conversion, including older age; higher body mass index; higher Tönnis grade; labral debridement; and advanced breakdown of the CLJ, labrum, or articular cartilage. Survivorship at 10 years was inferior in patients exhibiting severe (43.6%; 95% CI, 31.9%-59.7%) versus mild (97.9%; 95% CI, 95.1%-100%) breakdown of the CLJ (P < .001). Multivariable analysis identified worsening CLJ breakdown (weighted hazard ratio per 1-unit increase, 6.41; 95% CI, 3.11-13.24), older age (1.09; 95% CI, 1.04-1.14), and higher Tönnis grade (4.59; 95% CI, 2.13-9.90) as independent negative prognosticators (P < .001 for all).

CONCLUSION

Although most patients achieved favorable minimum 8-year outcomes, several pre- and intraoperative factors were associated with THA conversion; of these, worse CLJ breakdown, higher Tönnis grade, and older age were the strongest predictors.

Increased Alpha Angles and Younger Age Increase the Risk of Contralateral Femoral Acetabular Impingement Syndrome Symptom Development and Surgical Intervention: A Systematic Review

PURPOSE

To identify the preoperative risk factors associated with contralateral symptom development and surgical intervention for patients presenting with unilateral femoral acetabular impingement (FAI) syndrome.

METHODS

A literature search was performed using PubMed and Scopus computerized databases according to the 2020 Preferred Reporting Items for Systematic Meta-Analyses guidelines. Studies evaluating preoperative risk factors associated with the contralateral progression of FAI were included. Quality assessment was completed using the Methodological Index for Non-Randomized Studies criteria.

RESULTS

A total of 5 studies (n = 1,011 patients; mean age, 29.9 years) published from 2013 to 2022 met the inclusion/exclusion criteria. Mean follow-up ranged from 12 to 132 months. The overall rate of contralateral progression of symptomatic FAI ranged from 32.4% to 81%. Increased alpha angle was frequently reported factor associated with contralateral symptom progression, followed by decreased total arc of rotation, decreased internal rotation, reduced neck-shaft angle, and head-neck offset. The incidence rate of progression to contralateral surgery ranged from 15.7% to 24% of patients. Younger age was frequently reported factor associated with contralateral surgical intervention, followed by male sex, increased level of activity, and increased alpha angle.

CONCLUSIONS

Increased alpha angle and younger age were commonly reported risk factors associated with an increased risk of symptom development and surgical progression of contralateral FAI, respectively. The overall rate of contralateral progression of symptomatic FAI and the rate of progression to surgical intervention ranged up to 81% and 24%, respectively. This information may help both patients and surgeons to establish expectations regarding development of contralateral hip symptoms and possible need for surgery.

LEVEL OF EVIDENCE

Level III; systematic review of Level II-III studies.

Editorial Commentary: Younger Patients With Hip Femoroacetabular Impingement Syndrome and a Superolateral Cam Lesion Location May Require Aggressive Treatment to Prevent Post-Arthroscopy Total Hip Replacement

Hip femoroacetabular impingement syndrome is observed in 47% to 74% of patients with hip pain. Femoroacetabular impingement syndrome may result in osteoarthritis. It is well known that cam lesion volume and hip alpha angle are critical parameters determining patient outcomes. Recent research shows that a superolateral cam lesion location increases risk of hip arthroplasty at 5 years, and that this is more common in younger patients. The clinical relevance is that we may need to more aggressively treat superolateral cam lesions in younger patients, pending additional research to determine whether location is destiny.

[Risk factors for hip osteoarthritis after arthroscopy in patients with femoroacetabular impingement]

OBJECTIVE

To investigate the risk factors of hip osteoarthritis（HOA） after hip arthroscopy in patients with femoro-acetabular impingement（FAI） syndrome, and to reduce and prevent HOA.

METHODS

From September 2018 to September 2020, 106 patients with FAI underwent hip arthroscopy, including 40 males and 66 females, aged from 20 to 55 years old with an average age of （33.05±10.19） years old. The mechanism of injury included 51 cases for sports injury, 36 for traffic accidents, and 19 for blunt object injury. The duration of the disease ranged from 5 to 19 days with an average of （12.02±3.69） days. All patients were followed up for 18 months. Patients were divided into HOA group （23 cases） and non-HOA group （83 cases） according to the occurrence of HOA. Multivariate Logistic regression was used to analyze the risk factors of HOA after hip arthroscopy in FAI patients.

RESULTS

By univariate analysis, aged from 50 to 70 years old, female, body mass index（BMI）> 30 kg·m-2, physical labor, cam type, postoperative infection, last follow-up hip degree of motion （range of motion, ROM） （flexion, abduction, adduction, internal rotation） and Tönnis grade 1 and above of the HOA group were higher than those of the non-HOA group （P<0.05）, and the relative appendicular skeletal muscle index （RASM） was lower than that of non-HOA group（P<0.05）. By multiple Logistic regression analysis, cam type, BMI>30 kg·m-2, last follow-up hip internal rotation ROM and Tönnis grade 1 were risk factors for HOA after hip arthroscopy in FAI patients （P<0.05）.

CONCLUSION

FAI classification, body mass index, hip ROM and Tönnis grade are all related to HOA after hip arthroscopy in FAI patients. Follow-up and intervention should be strengthened in high-risk FAI patients to reduce the occurrence of HOA.

Hip Pain in Adolescent Patients

Hip pain is a common complaint in adolescents. There are several causes for hip pain in this population, with dysplasia and impingement being the most common; however, other conditions such as extra-articular impingement, torsional disorders, labral tears, and osteochondral lesions also require consideration. Many of these conditions are related to underlying anatomic abnormalities and increased activity in this age group. An understanding of the common pathologies of the adolescent hip is integral to the evaluation, diagnosis, and treatment of these patients.

[What surgical treatment for femoro-acetabular impingement?]

Femoroacetabular impingement (FAI) is a frequent cause of hip pain in young people and athletes. It requires a complete work-up, including X-rays, hip arthro-MRI and CT coxometry with measurement of femoral torsion. The surgical management of CFA must be adapted to the morphological anomalies of the femur (cam), acetabulum (pincer) and femoral torsional disorders. Most CFA can be treated by hip arthroscopy, with correction of the cam and suture of the labrum. Some CFA with a bulky or posterior cam require surgical hip dislocation. A femoral rotation or derotation osteotomy can correct an associated torsional disorder. In cases of marked retroversion of the acetabulum, anteverting periacetabular osteotomy can reorient the acetabulum.

Over 50% of Studies Report Low-Back Pain Is Associated With Worse Outcomes After Hip Arthroscopy When Compared With a Control Group: A Systematic Review

PURPOSE

To review outcomes of patients with low-back pathology undergoing primary hip arthroscopy for the treatment of femoroacetabular impingement (FAI) syndrome.

METHODS

The PubMed, Cochrane Trials, and Scopus databases were queried in June 2022 to conduct this systematic review using the following terms: ("hip" OR "femoroacetabular impingement") AND ("arthroscopy" OR "arthroscopic") AND ("spine" OR "lumbar" OR "sacral" OR "hip-spine" OR "back") AND ("outcomes"). Articles were included if they reported on patient-reported outcomes (PROs) and/or clinical benefit of patients undergoing hip arthroscopy with concomitant low-back pathology. The review adhered to the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) criteria. Case reports, opinion articles, review articles, and technique articles were excluded from this study. Forest plots were created to analyze preoperative and postoperative outcomes among patients with low-back pathology.

RESULTS

Fourteen studies were included in the review. There were 750 hips with low-back pathology and FAI (hip-spine syndrome) and 1,800 hips with only FAI (no hip-spine syndrome). All 14 studies reported PROs. In 4 studies in the group with hip-spine syndrome and 8 studies in the group with FAI without low-back pathology, the respective cohorts were reported to achieve the minimal clinically important difference in at least 1 PRO at a rate of 80%. Eight studies reported that patients with low-back pathology were associated with inferior outcomes or clinical benefit compared with patients without low-back pathology.

CONCLUSIONS

Patients undergoing primary hip arthroscopy with concomitant low-back pathology can expect favorable outcomes, but outcomes are superior in patients undergoing hip arthroscopy for FAI alone compared with FAI with concomitant low-back pathology.

LEVEL OF EVIDENCE

Level IV, systematic review of Level II to Level IV studies.

Groin pain of neurological origin as a differential diagnosis of femoroacetabular impingement

BACKGROUND

To describe the experience in the diagnostic process and treatment of patients with groin pain (GP) of neurological origin due to entrapment of the iliohypogastric (IH), ilioinguinal (IL) and genitofemoral (GF) nerves in a hip preservation clinic.

METHODS

Retrospective study of patients with GP of neurological origin confirmed with ultrasound-guided nerve block. Clinical outcomes were reported in 21 cases (age, 53.3 ± 15.9 years) treated with conservative treatment from January to December 2019, and in 9 patients (age 43.7 ± 14.6 years) who underwent neurectomy from January 2015 to December 2019. Pain intensity was assessed with a numerical rating scale (NRS) before starting the diagnostic process (Day 0) and at the end of follow-up.

RESULTS

All cases reported pain on groin palpation. Half of these cases also reported a positive FADIR test (flexion, adduction, internal rotation) (15/30). On day 0, the intensity of pain in cases treated with conservative treatment was severe in 19 patients (NRS 7-10) and moderate in 2 (NRS 4-6), with a median improvement of 7 points (interquartile range [IQR] 5.5-8.0) at the end of follow-up (p < 0.001). In neurectomy group, a similar improvement in pain severity was (Day 0: 9 points [IQR 8.0-9.0]; end of follow-up: 0 points [IQR: 0-2.0]; p = 0.002). At the end of the study, 17/21 patients with conservative treatment and 7/9 with neurectomy were pain free or with mild pain (NRS < 3).

CONCLUSIONS

In cases with PG of neurological origin, there is a high frequency of false positives in the FADIR test. Our findings suggest that neurectomy is a treatment option for patients in whom conservative treatment fails, providing significant pain relief.

The Impact of Age on Clinical Outcomes of Acetabular Microfracture During FAI Surgery

BACKGROUND

Full-thickness acetabular cartilage lesions are common findings during primary surgical treatment of femoroacetabular impingement (FAI).

PURPOSE

To evaluate clinical outcomes after acetabular microfracture performed during FAI surgery in a prospective, multicenter cohort.

STUDY DESIGN

Cohort Study; Level of evidence, 3.

METHODS

Patients with FAI who had failed nonoperative management were prospectively enrolled in a multicenter cohort. Preoperative and postoperative (mean follow-up, 4.3 years) patient-reported outcome measures were obtained with a follow-up rate of 81.6% (621/761 hips), including 54 patients who underwent acetabular microfracture. Patient characteristics, radiographic parameters, intraoperative disease severity, and operative procedures were analyzed. Propensity matching using linear regression was used to match 54 hips with microfracture to 162 control hips (1:3) to control for confounding variables. Subanalyses of hips ≤35 and >35 years of age with propensity matching were also performed.

RESULTS

Patients who underwent acetabular microfracture were more likely to be male (81.8% vs 40.9%; P < .001), be older in age (35.0 vs 29.9 years; P = .001), have a higher body mass index (27.2 vs 25.0; P = .001), and have a greater alpha angle (69.6° vs 62.3°; P < .001) compared with the nonmicrofracture cohort (n = 533). After propensity matching to control for covariates, patients treated with microfracture displayed no differences in the modified Harris Hip Score or Hip Disability and Osteoarthritis Outcome Score (P = .22-.95) but were more likely to undergo total hip arthroplasty (THA) (13% [7/54] compared with 4% [6/162] in the control group; P = .002), and age >35 years was associated with conversion to THA after microfracture. Microfracture performed at or before 35 years of age portended good outcomes with no significant risk of conversion to THA at the most recent follow-up.

CONCLUSION

Microfracture of acetabular cartilage defects appears to be safe and associated with reliably improved short- to mid-term results in younger patients; modified expectations should be realized when full-thickness chondral lesions are identified in patients >35 years of age.

CT-guided quadratus femoris injection for ischiofemoral impingement

OBJECTIVES

To describe the technique, efficacy, and safety of CT-guided quadratus femoris injection with corticosteroid and local anesthetic for the treatment of ischiofemoral impingement in a series of cases at our institution.

METHODS

Cases of CT-guided quadratus femoris injections from 2000 to 2021 were identified in the enterprise-wide electronic medical record of our institution. Patient charts and our institutional picture archiving and communication system (PACS) were searched for demographics, pain level on a 0-10 scale before and immediately following the procedure, procedure technique, and follow-up outcomes if available.

RESULTS

There were 13 cases among 12 patients with clinical and imaging findings of ischiofemoral impingement included in this study. Of the 12 patients, 10 were female and two were male. There were eight posterior approaches and five posterolateral approaches. Of the 13 cases, 11 resulted in immediate pain reduction. The median reduction in pain score was four (average 3.46, range 0-8.5). There was no statistically significant difference in pain reduction between the posterior approach cases and the posterolateral approach cases. No cases reported immediate complications or increases in pain score. Of the 12 cases, seven resulted in at least 1 month of pain relief, three had subsequent surgeries, and three had no follow-up.

CONCLUSION

CT-guided quadratus femoris injection is safe and effective for treating ischiofemoral impingement. Further and larger scale study is needed to fully delineate differences in technique effectiveness.

KEY POINTS

• CT-guided quadratus femoris injection is safe and effective for treating ischiofemoral impingement. • We found no statistically significant difference in pain reduction between the posterior approach and the posterolateral approach.

Does Femoroacetabular Impingement Syndrome Affect Self-Reported Burden in Football Players With Hip and Groin Pain?

BACKGROUND

It is unknown if football players with femoroacetabular impingement (FAI) syndrome report worse burden than those with other causes of hip/groin pain, and to what extent this is mediated by cartilage defects and labral tears.

HYPOTHESIS

Football players with FAI syndrome would report worse burden than other symptomatic players, with the effect partially mediated by cartilage defects and/or labral tears.

STUDY DESIGN

Cross-sectional study.

LEVEL OF EVIDENCE

Level 4.

METHODS

Football (soccer and Australian football) players (n = 165; 35 women) with hip/groin pain (≥6 months and positive flexion-adduction-internal rotation test) were recruited. Participants completed 2 patient-reported outcome measures (PROMs; the International Hip Outcome Tool-33 [iHOT-33] and Copenhagen Hip and Groin Outcome Score [HAGOS]) and underwent hip radiographs and magnetic resonance imaging (MRI). FAI syndrome was determined to be present when cam and/or pincer morphology were present. Cartilage defects and labral tears were graded as present or absent using MRI. Linear regression models investigated relationships between FAI syndrome (dichotomous independent variable) and PROM scores (dependent variables). Mediation analyses investigated the effect of cartilage defects and labral tears on these relationships.

RESULTS

FAI syndrome was not related to PROM scores (unadjusted b values ranged from -4.693 (P = 0.23) to 0.337 (P = 0.93)) and cartilage defects and/or labral tears did not mediate its effect (P = 0.22-0.97).

CONCLUSION

Football players with FAI syndrome did not report worse burden than those with other causes of hip/groin pain. Cartilage defects and/or labral tears did not explain the effect of FAI syndrome on reported burden.

CLINICAL RELEVANCE

FAI syndrome, cartilage defects, and labral tears were prevalent but unrelated to reported burden in symptomatic football players.

Hip-Spine Syndrome in the Nonarthritic Patient

Hip-spine syndrome refers to concurrent hip and spine pathology with overlapping symptoms. Most of the literature has studied it in relation to total hip arthroplasty literature and has been shown to increase dislocation risk. Lumbar spine and pelvic mobility have been studied less frequently in relation to nonarthritic pathologic hip states. Understanding the biomechanical relationship between the lumbar spine, pelvis, and hip can help elucidate how hip-spine syndrome affects the nonarthritic hip and how it impacts outcomes of hip arthroscopy. Changes in lumbar spine motion may be the reason certain predisposed patients develop symptomatic femoroacetabular impingement (FAI) or ischiofemoral impingement. Some athletes may be "hip users" with a low pelvic incidence, making them more reliant on hip motion due to less-intrinsic lumbopelvic motion. When these patients have FAI morphology, their increased reliance on hip motion makes them prone to experiencing femoroacetabular contact and concurrent symptoms. Other athletes may be "spine users," with larger pelvic incidence and more baseline lumbopelvic motion, making them less reliant on hip motion and therefore less prone to experiencing hip impingement even with hip FAI morphology. Hip-spine syndrome also appears to have an impact on patient selection, role of nonoperative treatment, and hip arthroscopy surgical outcomes. Identifying patients with concurrent pathology may allow surgeons to recommend targeted physical therapy or counsel patients better on their expectations after surgery.

Post-Related Complications in Hip Arthroscopy Are Reported Significantly Greater in Prospective Versus Retrospective Literature: A Systematic Review

PURPOSE

To determine whether there are differences in (1) the incidence of post-related complications following hip arthroscopy between prospective and retrospective publications; and (2) between post-assisted and postless techniques.

METHODS

A systematic review was performed using PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines to characterize post-related complications following hip arthroscopy for central or peripheral compartment hip pathology, including femoroacetabular impingement syndrome and chondrolabral injury. Inclusion criteria were prospective and retrospective Level I-IV evidence investigations that reported results of hip arthroscopy performed in the supine position. Exclusion criteria included open or extra-articular endoscopic hip surgery. Post-related complications included pudendal nerve injury (sexual dysfunction, dyspareunia, perineal pain or numbness) or perineum/external genitalia soft-tissue injury.

RESULTS

Ninety-four studies (12,212 hips; 49% male, 51% female; 52% Level IV evidence) were analyzed. Prospective studies (3,032 hips) report a greater incidence of post-related complications compared with retrospective (8,116 hips) studies (7.1% vs 1.4%, P < .001). Three studies (1,064 hips) used a postless technique and all reported a 0% incidence of pudendal neurapraxia or perineal soft tissue injury. Most pudendal nerve complications were transient, resolving by 3 months, but permanent nerve injury was reported in 4 cases. Only 19%, 22%, 7%, and 4% of studies reported a total surgery time, traction time, traction force, and bed Trendelenburg angle for their study samples, respectively.

CONCLUSIONS

The incidence of post-related complications is 5 times greater in prospective (versus retrospective) hip arthroscopy literature. Postless distraction resulted in a 0% incidence of post-related injuries.

LEVEL OF EVIDENCE

IV, systematic review of Level I-IV evidence.

How Does Chondrolabral Damage and Labral Repair Influence the Mechanics of the Hip in the Setting of Cam Morphology? A Finite-Element Modeling Study

BACKGROUND

Individuals with cam morphology are prone to chondrolabral injuries that may progress to osteoarthritis. The mechanical factors responsible for the initiation and progression of chondrolabral injuries in these individuals are not well understood. Additionally, although labral repair is commonly performed during surgical correction of cam morphology, the isolated mechanical effect of labral repair on the labrum and surrounding cartilage is unknown.

QUESTION/PURPOSES

Using a volunteer-specific finite-element analysis, we asked: (1) How does cam morphology create a deleterious mechanical environment for articular cartilage (as evaluated by shear stress, tensile strain, contact pressure, and fluid pressure) that could increase the risk of cartilage damage compared with a radiographically normal hip? (2) How does chondrolabral damage, specifically delamination, delamination with rupture of the chondrolabral junction, and the presence of a chondral defect, alter the mechanical environment around the damage? (3) How does labral repair affect the mechanical environment in the context of the aforementioned chondrolabral damage scenarios?

METHODS

The mechanical conditions of a representative hip with normal bony morphology (characterized by an alpha angle of 37°) and one with cam morphology (characterized by an alpha angle of 78°) were evaluated using finite-element models that included volunteer-specific anatomy and kinematics. The bone, cartilage, and labrum geometry for the hip models were collected from two volunteers matched by age (25 years with cam morphology and 23 years with normal morphology), BMI (both 24 kg/m2), and sex (both male). Volunteer-specific kinematics for gait were used to drive the finite-element models in combination with joint reaction forces. Constitutive material models were assigned to the cartilage and labrum, which simulate a physiologically realistic material response, including the time-dependent response from fluid flow through the cartilage, and spatially varied response from collagen fibril reinforcement. For the cam hip, three models were created to represent chondrolabral damage conditions: (1) "delamination," with the acetabular cartilage separated from the bone in one region; (2) "delamination with chondrolabral junction (CLJ) rupture," which includes separation of the cartilage from the labrum tissue; and (3) a full-thickness chondral defect, referred to throughout as "defect," where the acetabular cartilage has degraded so there is a void. Each of the three conditions was modeled with a labral tear and with the labrum repaired. The size and location of the damage conditions simulated in the cartilage and labrum were attained from reported clinical prevalence of the location of these injuries. For each damage condition, the contact area, contact pressure, tensile strain, shear stress, and fluid pressure were predicted during gait and compared.

RESULTS

The cartilage in the hip with cam morphology experienced higher stresses and strains than the normal hip. The peak level of tensile strain (25%) and shear stress (11 MPa) experienced by the cam hip may exceed stable conditions and initiate damage or degradation. The cam hip with simulated damage experienced more evenly distributed contact pressure than the intact cam hip, as well as decreased tensile strain, shear stress, and fluid pressure. The peak levels of tensile strain (15% to 16%) and shear stress (2.5 to 2.7 MPa) for cam hips with simulated damage may be at stable magnitudes. Labral repair only marginally affected the overall stress and strain within the cartilage, but it increased local tensile strain in the cartilage near the chondrolabral junction in the hip with delamination and increased the peak tensile strain and shear stress on the labrum.

CONCLUSION

This finite-element modeling pilot study suggests that cam morphology may predispose hip articular cartilage to injury because of high shear stress; however, the presence of simulated damage distributed the loading more evenly and the magnitude of stress and strain decreased throughout the cartilage. The locations of the peak values also shifted posteriorly. Additionally, in hips with cam morphology, isolated labral repair in the hip with a delamination injury increased localized strain in the cartilage near the chondrolabral junction.

CLINICAL RELEVANCE

In a hip with cam morphology, labral repair alone may not protect the cartilage from damage because of mechanical overload during the low-flexion, weightbearing positions experienced during gait. The predicted findings of redistribution of stress and strain from damage in the cam hip may, in some cases, relieve disposition to damage progression. Additional studies should include volunteers with varied acetabular morphology, such as borderline dysplasia with cam morphology or pincer deformity, to analyze the effect on the conclusions presented in the current study. Further, future studies should evaluate the combined effects of osteochondroplasty and chondrolabral treatment.

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.

Why Does Hip Arthroscopy Fail? Indications and PEARLS for Revision Success

The surgical treatment of femoroacetabular impingement has been shown to have successful early and mid-term clinical outcomes. Despite these favorable clinical outcomes that have been published in the literature, there is a subgroup of patients that present with continued or recurrent symptoms after surgical treatment. Not only has there been an increase in the number of hip arthroscopy procedures, but also there has been a corresponding increase in the number of revision hip arthroscopy and hip preservation surgeries. Previous studies have reported residual deformity to be the most common reason for revision hip arthroscopy. However, chondral, labral, and capsular considerations also are important when addressing patients not only in the primary but also, the revision setting. In this review, we outline the evaluation and treatment of the patient that presents with continued hip and groin pain after undergoing a hip.

The prevalence of athletic pubalgia imaging findings on MRI in patients with femoroacetabular impingement

OBJECTIVE

To determine the prevalence of athletic pubalgia imaging findings on MRI in patients with femoroacetabular impingement and assess for correlative risk factors.

MATERIALS AND METHODS

A retrospective search identified 156 hips with femoroacetabular impingement and a control group of 113 without femoroacetabular impingement that had an MRI performed between January 1, 2015, and January 1, 2018. Two fellowship-trained musculoskeletal radiologists reviewed studies for the presence of acute osteitis pubis, chronic osteitis pubis, adductor tendinosis, and tendon tear; rectus abdominis tendinosis and tendon tear; and aponeurotic plate tear. Findings were correlated with various clinical and imaging risk factors. Univariate and multivariate statistical analyses were performed.

RESULTS

Imaging findings of adductor tendinosis (p = 0.02) and chronic osteitis pubis (p = 0.01) were more prevalent in FAI patients than controls. Univariate analyses in FAI patients showed that an alpha angle ≥ 60° had a higher prevalence of aponeurotic plate tears (p = 0.02) and adductor tendinosis (p = 0.049). Multivariate analyses showed that an alpha angle ≥ 60° had a higher prevalence of chronic osteitis pubis (OR = 2.27, p = 0.031), sports participation had a higher prevalence of adductor tendon tears (OR = 4.69, p = 0.013) and chronic osteitis pubis (OR = 2.61, p = 0.0058), and males had a higher prevalence of acute osteitis pubis (OR = 5.17, p = 0.032).

CONCLUSION

Sports participation, alpha angle ≥ 60°, and male sex predict a higher prevalence of athletic pubalgia imaging findings in patients with femoroacetabular impingement.

[From Pathomorphology to Hip Osteoarthritis - Femoroacetabular Impingement as an Example]

From Pathomorphology to Hip Osteoarthritis - Femoroacetabular Impingement as an Example Abstract. Femoroacetabular impingement (FAI) occurs due to abnormal morphology and subsequent contact between the proximal femur and the acetabulum and can be a source of labral and chondral damage in the hip joint. While there is evidence that Cam-type FAI is correlated with hip osteoarthritis, there is yet no clear link between osteoarthritis and Pincer-FAI in which primarily the labrum gets injured. Hips with evident deformity and beginning chondral and/or labral damage should undergo surgery. Most cases (80-90 %) can be successfully treated by hip arthroscopy. At the time of surgery, the typical FAI-patient is 30 years old. With correct indication and proper surgical technique, favorable outcomes are achieved in more than 80 % of the cases at a short- to mid-term follow-up.

The association between anterior femoroacetabular impingement and femoral neck fractures: An observational study

The impact between acetabulum and femoral neck is another possible mechanism of femoral neck fracture.Direct trauma of the greater trochanter may not be able to fully explain the mechanism underlying femoral neck fracture. In this study, we sought to investigate whether anterior femoroacetabular impingement are associated with femoral neck fractures.A total of 36 patients with femoral neck fracture who had undergone total hip arthroplasty or hemiarthroplasty were included in this study. These patients were divided into 2 groups: labrum tear group and normal labrum group. Patients' age, gender, body mass index, muscle injury, injury pattern, trauma severity, femoral head-neck offset, femoral head-neck ratio, Cam deformity alpha angle, acetabular anteversion, femoral head diameter, acetabular index, cortical index, hip axis length, and neck stem angle were recorded and analyzed. SPSS 18.0 software was used for statistical analyses.According to intraoperative findings, 22 patients exhibited a labrum tear. Magnetic resonance imaging examination revealed bone contusion on the anterolateral margin of the acetabulum with muscle damage surrounding the hip. Among 14 cases without a labrum tear, no bone contusion and obvious muscle injury were found on the anterolateral margin of the acetabulum. Notably, muscle injury, injury pattern, trauma severity and femoral head-neck offset differed significantly (P < .05) between labrum tear and normal labrum groups.Previous studies have focused more on direct lateral trauma. In this study, the impact between acetabulum and femoral neck is another possible mechanism besides lateral impact. Specifically, the abnormal anatomy of the hip, such as femoral head-neck offset, may promote the fracturing process.

The Painful Hip in Young Adults Between Impingement and Mild Dysplasia: Clinical and Instrumental Diagnostical Criteria

Femoroacetabular impingement and developmental dysplasia of the hip are among the main causes of hip arthritis. In absence of degenerative alterations of the hip, there is the chance of a surgical conservative treatment. This study aims to show the clinical and imaging criteria to a correct and prompt diagnosis.

Rapidly Progressive Arthritis in Femoroacetabular Impingement: Patient Characteristics and Risk Factors for Total Hip Arthroplasty by the Age of Forty

BACKGROUND

Femoroacetabular impingement (FAI), particularly cam-type, is now well accepted as a risk factor for the development of hip osteoarthritis (OA). However, many hips with FAI morphology will never develop hip pain or OA, identifying that our current understanding of FAI disease progression remains limited. The purposes of this retrospective case-control study were to (1) report the patient and disease characteristics of patients with rapidly progressive FAI requiring hip arthroplasty by the age of 40 and (2) to identify patient and imaging factors associated with rapidly progressive FAI.

METHODS

Cases were retrospectively identified from an arthroplasty registry as patients 40 years old or younger with underlying FAI deformity and end stage OA requiring primary total hip arthroplasty. Patients were excluded for known DDH, AVN, SCFE, inflammatory arthritis, and previous ipsilateral surgery. Controls were identified from a hip preservation database as patients with symptomatic FAI undergoing surgical intervention over the same time period, and were matched 2:1 by gender and age. Alpha angles were calculated on frog-leg lateral and anteroposterior (AP) radiographs with both inclusion and exclusion of any osteophytic prominences (representing minimum and maximal possible underlying FAI morphology). Patient characteristics, radiographic parameters, and baseline patient reported outcomes were compared between the two groups using student's t-tests.

RESULTS

The rapidly progressive FAI cohort of 31 patients had a mean age of 35.8 years at surgery and was 39% female and 61% male. Alpha angles were significantly larger compared to controls when osteophytes were included (Frog: 74.7±10.8 vs. 57.2±12.7°, p<0.001; AP: 91.7±10.7 vs. 61.2±19.4°, p<0.001), but not when osteophytes were excluded (Frog: 61.2±11.1 vs. 57.2±12.7°, p=0.15; AP: 64.9±17.1 vs. 61.3±19.4°, p=0.38). Except for UCLA activity score, all baseline outcome measures were significantly lower for rapidly progressive FAI cases (p<0.001 for all).

CONCLUSIONS

When compared to controls with symptomatic FAI, rapidly progressive cases did not demonstrate major differences in cam deformity magnitude. Thus severity of bony deformity may only be one aspect of a multifactorial etiology of hip OA progression in FAI.Level of Evidence: III.

Biomarkers for Femoroacetabular Impingement and Hip Osteoarthritis: A Systematic Review and Meta-analysis

BACKGROUND

The early recognition and management of patients with hip lesions, such as femoroacetabular impingement (FAI) and early hip osteoarthritis (OA), may preempt significant hip morbidity. The identification of reliable biomarkers may help guide decision making in an efficient and cost-effective manner.

PURPOSE

To determine the biomarkers that have been associated with FAI as well as identify serum, synovial, and urinary analytes that have shown clinical utility in the prediction or identification of hip OA.

STUDY DESIGN

Systematic review and meta-analysis.

METHODS

The terms "hip arthroscopy," "femoroacetabular impingement," "labral tear," "osteoarthritis," and "biomarker" were searched in PubMed, Web of Science, Scopus, Cochrane Library, and Google Scholar, yielding 276 articles. After screening, 7 articles were included. Pooled estimates were calculated utilizing a fixed-effects inverse-variance model weighted for individual study size.

RESULTS

A total of 1747 patients with a mean age of 37.5 ± 4.5 years (76.4% female) were identified. Forty-three unique biomarkers were assessed. Although general proinflammatory cytokines IL-1 and TNF-α exhibited inconsistent trends in arthritic hips, IL-6 demonstrated a consistent increase (+84.8% [95% CI, 81.9%-87.6%]; P < .05). A significant difference was found in levels of the fibronectin-aggrecan complex (FAC) in patients with OA compared with controls (0.08 ± 0.40 vs 1.15 ± 0.35 μg/mL, respectively; P < .001). It was the only specific analyte to show a significant difference between those with and without OA. In the setting of FAI, cartilage oligomeric matrix protein (COMP) was significantly increased in athletes after adjusting for concurrent knee and hip OA. A statistically significant difference was present in FAI-positive hips (9.0 ± 0.1 [95% CI, 8.8-9.3]) compared with controls (8.4 ± 0.1 [95% CI, 8.2-8.4]) (P < .05). Other biomarkers, such as CXCL3, which exhibited statistically significant differences compared with controls, did not control for underlying factors such as age and concomitant lesions.

CONCLUSION

COMP and FAC are specific biomarkers with potential utility in the diagnosis and management of FAI and hip OA, given their ability to differentiate between controls and patients with hip lesions. Further research is necessary to identify their ability in determining disease severity, predicting the response to treatment, and establishing an association with the risk of long-term OA.

Acetabular Retroversion Is a Risk Factor for Less Optimal Outcome After Femoroacetabular Impingement Surgery

BACKGROUND

Patients with acetabular retroversion are at risk of labral tear and hip pain. It is unknown whether femoroacetabular osteoplasty (FAO) without reverse periacetabular osteotomy can be used in these patients. This study evaluated the outcome of mini-open FAO in patients with acetabular retroversion and compared that to patients without acetabular retroversion.

METHODS

Fifty-one patients (29 male, 22 female) with acetabular retroversion who had undergone FAO between 2007 and 2015 were identified. The minimum 2-year clinical and radiological outcome was compared with 550 patients without dysplasia or retroversion who underwent FAO by the same surgeon. The preoperative and postoperative alpha angle, center-edge angle, Tonnis grade, joint space, and presence of labral tear and chondral lesion were determined.

RESULTS

The mean age in the retroversion cohort was 27.4 ± 9.5 years compared to 34.5 ± 11.2 years in the control. The mean follow-up was 4.8 ± 1.5 years for retroversion and 4.1 ± 1.2 years for the control. The mean preoperative Short-Form 36 Health Survey and modified Harris hip score were not different between the cohorts. At the latest follow-up, the mean modified Harris hip score and Short-Form 36 Health Survey were significantly lower in the retroversion group (75.4 and 76.5) compared to the control (83.4 and 85.6). There was a higher percentage of failure among retroversion patients (13.7%) compared to the control (2.5%).

CONCLUSION

Acetabular retroversion resulting in femoroacetabular impingent may be treated by FAO, but the outcome appears to be less optimal compared to patients with femoroacetabular impingent and no evidence of dysplasia and acetabular retroversion. Hip preservation surgeons should be aware of this anatomic variation and possible inferior treatment results after FAO in these patients.

Bilateral Hip Arthroscopy: Can Results From Initial Arthroscopy for Femoroacetabular Impingement Predict Future Contralateral Results?

PURPOSE

To determine the degree of correlation of radiographic measurements, degree of correlation of intraoperative pathology, and difference in outcomes between sides of patients requiring staged bilateral hip arthroscopy.

METHODS

Two high-volume hip preservation centers retrospectively reviewed hip preservation databases for staged bilateral hip arthroscopies conducted between 2008 and 2015. Patients were separated into those who presented with bilateral hip pain and those that presented with unilateral pain and developed contralateral pain >2 years later. Patients were analyzed for radiographic correlation (alpha angle, lateral center edge angle, anterior center edge angle, magnetic resonance imaging alpha angle, Tönnis grade) and correlation of intraoperative pathology (acetabular labrum articular disruption grade, Outerbridge grade/location, Villar class ligamentum teres tears, labral tear location, symmetry of Seldes tear types, and the differences between operative procedures). Patient-reported outcomes were analyzed (modified Harris Hip Score, Non-Arthritic Hip Score, International Hip Outcome Tool-12, hip outcome score-sport specific subscale, visual analog scale, patient satisfaction). Correlative tests included Pearson and Spearman; univariate and multivariate analysis for differences included χ-square test and Student t tests for ordinal and continuous variables respectively.

RESULTS

A total of 133 of 2,705 patients (4.6%) underwent bilateral hip arthroscopy. Radiographic alpha angle, magnetic resonance imaging alpha angle, lateral center edge angle, and anterior center edge angle demonstrated strong correlation (Pearson's coefficients 0.651, 0.648, 0.644, 0.667, respectively, P < .0001). Tönnis grade was weakly correlated (Pearson's coefficient 0.286, P = .001). Intraoperative pathology was moderately correlated (Pearson's coefficients for acetabular Outerbridge location, 0.300, P = .0170; acetabular labrum articular disruption, 0.490, P < .0001; acetabular Outerbridge; 0.530; P < .0001; femoral head Outerbridge, 0.459, P < .0001; Villar class, 0.393, P < .0001; and labral tear location, 0.468, P < .0001). Labral tear Seldes type was compared with Bowker's symmetry test and there was no significant difference between sides. There were no significant differences in surgical interventions performed between sides. Patients with bilateral hip arthroscopies significantly improved in all measured patient-reported outcomes and had a high patient satisfaction after both procedures. Final patient-reported outcomes and change in patient-reported outcomes were not different between procedures; follow up ranged from 3 months to 8 years.

CONCLUSIONS

This study demonstrated an incidence of 4.6% of patients who require bilateral hip arthroscopy. These patients can expect significant improvement after surgical intervention. Patients that had 1 side done gained similar improvement when the contralateral side was performed. Preoperative radiographic, intraoperative pathology, and procedures performed were similar between hips.

LEVEL OF EVIDENCE

Level III, retrospective cohort study.

Hip Dysplasia Compromises the Outcome of Femoroacetabular Impingement Surgery

BACKGROUND

The optimal treatment for patients with symptomatic hip dysplasia presenting with labral tear is unknown. Although femoroacetabular osteoplasty (FAO) has excellent outcome for most femoroacetabular impingement patients, the presence of concomitant hip dysplasia has been implicated as an adverse prognostic factor. This study evaluated the outcome of FAO in a group of dysplastic hips and compared the outcome to a cohort of patients without dysplasia.

METHODS

Seventy-three patients (38 males, 35 females) with hip dysplasia who underwent FAO between 2007 and 2015 were identified. The minimum 2-year clinical, functional (modified Harris Hip Score and Short-Form 36 Health Survey), and radiological outcome was compared with 550 patients without dysplasia who underwent FAO by the same surgeon. The preoperative and postoperative alpha angle, Tonnis grade, joint space, and presence of chondral lesion were determined and compared. Conversion to total hip arthroplasty or revision FAO was considered as treatment failure.

RESULTS

The mean age in the dysplasia cohort was 30.7 ± 11.8 years compared to 34.5 ± 11.2 in the nondysplastic group. The mean follow-up was 4.3 years for dysplasia cohort and 4.1 for the nondysplastic group. The mean modified Harris Hip Score and Short-Form 36 Health Survey6 was significantly lower in the dysplastic group at 75.1 and 74.3 compared to 83.4 and 85.6 for the comparison group. There was a higher percentage of failure at 28.8% among dysplasia patients compared to 2.5% in the nondysplastic group.

CONCLUSION

Although labral repair and FAO may be an option for patients with hip dysplasia, the outcome in this population appears to be less optimal compared to femoroacetabular impingement patients with no evidence of dysplasia. Labral repair and osteoplasty should be limited to those with mild and borderline dysplasia.

Is There an Association Between Noncontact Anterior Cruciate Ligament Injuries and Decreased Hip Internal Rotation or Radiographic Femoroacetabular Impingement? A Systematic Review

PURPOSE

To perform a systematic review to determine if there is (1) an association between decreased hip internal rotation and anterior cruciate ligament (ACL) tear rates; (2) an association between radiographic femoroacetabular impingement (FAI) and ACL tear rates; and (3) biomechanical evidence demonstrating increased strain in the ACL of patients with decreased hip internal rotation.

METHODS

A systematic review was performed using Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Studies investigating relationships between hip motion, hip radiographs, and ACL tear were sought. Studies with Levels of evidence I-IV were eligible for inclusion. Study methodology/evidence were evaluated using Methodological Index for Non-Randomized Studies (MINORS), Strengthening the Reporting of Observational Studies in Epidemiology (STROBE), and Grading of Recommendations Assessment, Development, and Evaluation (GRADE) criteria.

RESULTS

Eleven studies were analyzed (2 cadaveric in vitro models, 8 clinical studies measuring hip internal rotation (2 concurrently assessing radiographic FAI), and 1 clinical study assessing radiographic FAI alone). Mean MINORS, STROBE, and GRADE for the studies was 82.4%, 20.9 out of 22, and "low," respectively. A total of 959 subjects (84.8% male; mean age 23.6 ± 3.8 years) were analyzed. Overall, 378 subjects sustained 427 ACL tears (399 primary ACL ruptures, 28 reruptures). Six of 8 clinical studies identified a significant association between limited rotation (internal rotation [IR; loss greater than 10°-20°], external rotation [ER], or combined IR + ER [loss greater than 20°]) and ACL tears. Two studies found an association between ACL ruptures and radiographic cam/pincer impingement. Two cadaveric models found a significant association between ACL strain and limited hip internal rotation.

CONCLUSIONS

This systematic review identified a significant association between ACL tear and both limited hip rotation and radiographic FAI.

LEVEL OF EVIDENCE

Level IV, systematic review of Levels II-IV studies.

Gait deviations in transverse plane after SCFE in dependence on the femoral offset

Residual deformity of the femoral head after slipped capital femoral epiphysis (SCFE) may be accompanied by a loss of femoral offset and lead to femoro-acetabular impingement (FAI), especially during hip flexion. It is hypothesized that during phases of the gait cycle, when the hip is flexed, the offset-loss is compensated by an increased external rotation. The gait pattern of 36 patients suffering from SCFE, who were treated by pinning-in-situ, were compared to a control group of 40 healthy adults by an instrumented 3D-gait analysis. Total patient group was subdivided into 3 subgroups in dependence on the offset (offset groups (OG)) quantified by the angle α according to Nötzli: OG1: α-angle <55°, OG2: α-angle between 55 and 75°, OG3: α-angle >75°. Comparisons were made at 3 instants: initial foot contact (0% gait cycle (GC)), 40-60% GC and 90-100% GC. Patients showed an increased external hip rotation during all 3 periods of the GC with a tendency of increasing external rotation in association with offset-loss. Only during hip extension (40-60% GC) there was a weak correlation between angle α and hip rotation (r=-0.375, p=0.024). In conclusion, the offset-loss does not lead to a functional relevant impingement during walking which needs compensation strategies like increasing external rotation during periods of hip flexion.

What Are the Risk Factors for Revision Surgery After Hip Arthroscopy for Femoroacetabular Impingement at 7-year Followup?

BACKGROUND

In recent years, surgical treatment of symptomatic femoroacetabular impingement (FAI) has been increasingly performed using arthroscopy. Bony pathomorphologies and damage to the labrum as well as cartilage defects can be addressed with comparable results to open surgery with overall less surgery-related complications. Despite the increasing importance of hip arthroscopy, however, reports on midterm clinical and radiographic outcomes and comparison to open surgical hip dislocation are scarce.

QUESTIONS/PURPOSES

(1) What are the clinical and radiographic outcomes at a mean 7-year followup; (2) what is the cumulative 7-year survivorship, using the endpoints of THA, progression of osteoarthritis according to Tönnis, or poor clinical outcome with a Merle d'Aubigné score of less than 15 points, of hips with symptomatic FAI treated arthroscopically; and (3) what factors were associated with revision surgery?

METHODS

Between 2003 and 2008 we performed a total of 62 arthroscopic procedures (60 patients) for FAI. For the same indication, we also performed 571 surgical hip dislocations during that time. Standardized treatment was femoral offset correction, acetabular rim trimming, or both and treatment of labral or chondral defects. An arthroscopic approach was generally used if the pathomorphology was located in the anterosuperior quadrant of the hip and was gradually used for more complex cases. We excluded 10 hips (10 patients) in which the standardized treatment was not achieved and no offset correction or acetabular rim trimming was performed. Of the remaining 52 hips (50 patients), 39 hips underwent isolated femoral offset correction, four hips isolated acetabular rim trimming, and nine hips both procedures. At a mean followup of 7 years (range, 5-11 years), the Merle d'Aubigné clinical score was obtained and plain radiographs were examined (Tönnis grade, heterotopic ossification, lateral center-edge [LCE] angle, acetabular index [AI], extrusion index, alpha angle, and pistol grip deformity). Cumulative survivorship was calculated according to Kaplan-Meier using conversion to THA, progression of osteoarthritis (one or more Tönnis grades), or poor clinical outcome (Merle d'Aubigné score < 15 points) as endpoints. Cox regression analysis was used to identify univariate factors associated with revision surgery.

RESULTS

At last followup we detected a significant but possibly not clinically relevant increase in Merle d'Aubigné scores from preoperative levels to latest followup (14 ± 1 versus 16 ± 2, mean difference 2 points with a 95% confidence interval [95% CI] -3 to 7, p < 0.001). Six hips showed progression of osteoarthritis. Cumulative survivorship (hips free from conversion to THA, progression of osteoarthritis, or poor clinical outcome) of hips treated with hip arthroscopy for FAI at a mean followup of 7 years was 81% (95% CI, 68%-95%). Two patients (two hips, 4%) underwent THA at 7 and 9 years, respectively. An increased preoperative acetabular coverage (LCE angle, AI), increased offset in the superior portion of the femoral neck (pistol grip deformity), and a remaining pistol grip deformity postoperatively were associated with revision surgery. Any treatment of the labrum did not influence the outcome. Factors associated with failure could not be identified.

CONCLUSIONS

In this series of patients with arthroscopic treatment of symptomatic FAI, hip arthroscopy resulted in an intact hip without progression of osteoarthritis and with a Merle d'Aubigné score of ≥ 15 points in 81% of patients at 7-year followup. Increased acetabular coverage and femoral pistol grip deformity were risk factors for revision surgery.

LEVEL OF EVIDENCE

Level IV, therapeutic study.

Poorer Arthroscopic Outcomes of Mild Dysplasia With Cam Femoroacetabular Impingement Versus Mixed Femoroacetabular Impingement in Absence of Capsular Repair

PURPOSE

To compare outcomes of mild dysplasia with cam femoroacetabular impingement (FAI) vs mixed FAI with hip arthroscopy without capsular repair.

METHODS

A retrospective review of a 2009 to 2010 multicenter prospective outcome study was performed comparing a cohort with mild dysplasia and cam femoroacetabular impingement (cohort D) to a cohort with mixed FAI (cohort M). Outcome measures included Nonarthritic Hip Score (NAHS) and satisfaction with minimum 2-year follow-up.

RESULTS

Of 150 patients/159 hips enrolled in the initial prospective outcome study, 10 patients/10 hips had acetabular dysplasia and 8 patients met the inclusion criteria. Cohort D had 8 patients (5 female) of mean age 49.6 years with mean lateral center-edge angle (LCEA) of 19° (range, 16°-24°) demonstrating a mean change in NAHS of +20.00 at 3 months (P = .25), +14.33 at 12 months (P = .03), and -0.75 at 24 months (P = .74). Mean satisfaction was 2.88 out of 5. Cohort M had 69 patients (32 female) of mean age 38.6 years with a mean LCEA of 33° (range, 25°-38°) demonstrating a mean change in NAHS of +12.09 at 3 months (P < .0001), +20.39 at 12 months (P < .0001), and +21.99 at 24 months (P < .0001). Mean satisfaction was 3.58 out of 5. Cohort D demonstrated significantly less improvement in NAHS (P = .002) and a difference of -31.06 points compared to cohort M at minimum 2-year follow-up. Dysplasia was the only statistically significant predictor of poorer outcomes.

CONCLUSION

The common combination of mild dysplasia and cam FAI has poorer outcomes than mixed FAI following arthroscopic surgery without capsular repair.

A comparison of multidisciplinary team residential rehabilitation with conventional outpatient care for the treatment of non-arthritic intra-articular hip pain in UK Military personnel - a protocol for a randomised controlled trial

BACKGROUND

Non-arthritic hip disorders are defined as abnormalities of the articulating surfaces of the acetabulum and femur before the onset of osteoarthritis, including intra-articular structures such as the acetabular labrum and chondral surfaces. Abnormal femoroacetabular morphology is commonly seen in young men who constitute much of the UK military population. Residential multidisciplinary team (MDT) rehabilitation for patients with musculoskeletal injuries has a long tradition in the UK military, however, there are no studies presenting empirical data on the efficacy of a residential MDT approach compared with individualised conventional outpatient treatment. With no available data, the sustainability of this care pathway has been questioned. The purpose of this randomised controlled trial is to compare the effects of a residential multidisciplinary intervention, to usual outpatient care, on the clinical outcomes of young active adults undergoing treatment for non-arthritic intra-articular hip pain.

METHODS/DESIGN

The trial will be conducted at the Defence Medical Rehabilitation Centre, Headley Court, UK. One hundred military male participants with clinical indicators of non-arthritic intra-articular hip pain will be randomly allocated to either: (1) 7-day residential multidisciplinary team intervention, n = 50; (2) 6-week physiotherapist-led outpatient intervention (conventional care), n = 50. Measurements will be taken at baseline, post-treatment (1-week MDT group; 6-weeks physiotherapy group), and 12-weeks. The primary outcome measures are the function in daily living sub-scale of the Copenhagen Hip and Groin Outcome Score (HAGOS), the physical function subscale of the Non-arthritic Hip Score (NAHS), and VAS pain scale. Secondary outcomes include objective measures of physical capacity and general health. An intention-to-treat analysis will be performed using linear and mixed models.

DISCUSSION

This study will be the first to assess the efficacy of intensive MDT rehabilitation, versus conventional outpatient care, for the management of non-arthritic hip pain. The results from this study will add to the evidence-base and inform clinical practice for the management of intra-articular non-arthritic hip pain and femoroacetabular impingement in young active adults.

TRIAL REGISTRATION

ISRCTN Reference: ISRCTN 59255714 dated 11-Nov-2015.

Hip Osteoarthritis: Etiopathogenesis and Implications for Management

Highly prevalent among the elderly, hip osteoarthritis (OA) carries a heavy burden of disease. Guidelines for the management of hip OA are often extrapolated from knee OA research, despite clear differences in the etiopathogenesis and response to treatments of OA at these sites. We propose that hip OA requires specific attention separate from other OA phenotypes. Our understanding of the etiopathogenesis of hip OA has seen significant advance over the last 15 years, since Ganz and colleagues proposed femoroacetabular impingement (FAI) as an important etiological factor. This narrative review summarizes the current understanding of the etiopathogenesis of hip OA and identifies areas requiring further research. Therapeutic approaches for hip OA are considered in light of the condition’s etiopathogenesis. The evidence for currently adopted management strategies is considered, especially those approaches that may have disease-modifying potential. We propose that shifting the focus of hip OA research and public health intervention to primary prevention and early detection may greatly improve the current management paradigm.

Hip Pain in the Pre-Arthritic Patient: A Guide for the Primary Care Physician

Adolescents and young adults (less than 30 years of age) with pre-arthritic hip pain constitute a diagnostic dilemma for the primary care physician. The most common underlying diagnoses range from benign muscle strains/joint sprains to stress reactions, insufficiency fractures, and tears involving the articular cartilage/labrum in the setting of femoroacetabular impingement, a hip shape abnormality that is present in up to 90% of this age group. Undetected or left untreated these seemingly innocuous disorders can result in significant loss of function and, in some cases, irreversible joint damage. Despite sharing common predisposing factors, many of the above diagnoses can be identified with a focused history and physical examination. Conservative management may be safely initiated without advanced imaging, reserving orthopaedic consultation for refractory cases or more serious diagnoses. The presented focused hip clinical examination has 98% sensitivity in localizing intra-articular hip pathology and will be helpful to direct appropriate referrals. This article will serve as a guide for primary care physicians undertaking the difficult task of evaluating and treating a young patient with hip pain.

Correlation Between Cam-Type Femoroacetabular Impingement and Radiographic Osteitis Pubis

A mechanistic link has been suggested between cam-type femoroacetabular impingement and increased stress on the symphysis pubis. This retrospective study was conducted to determine whether there is an increased prevalence of osteitis pubis, as evidenced by imaging, in patients with femoroacetabular impingement compared with age-matched control subjects. Search of a radiologic database of a large academic health institution for all patients with cam-type femoroacetabular impingement diagnosed by magnetic resonance imaging or magnetic resonance arthrogram between January 2000 and October 2013 identified 46 cases. Two radiologists reviewed these cases independently and confirmed the presence of femoroacetabular impingement based on alpha angle and other characteristics of cam morphology. The imaging studies were further evaluated for characteristics of osteitis pubis, with severity graded from minimal to severe on a 4-point Likert scale. A control group composed of age-matched subjects without diagnosed femoroacetabular impingement was also evaluated for osteitis pubis. A statistically significant increase in the prevalence of osteitis pubis was found in patients with femoroacetabular impingement compared with age-matched control subjects, with a prevalence of 43.48% in the femoroacetabular impingement group compared with 12.77% in the control group (P=.0012). On the 4-point Likert scale, the average severity of osteitis pubis in the group with femoroacetabular impingement was 1.5 (minimal to mild) compared with 0.53 (no osteitis pubis to minimal findings) in the control population. This significant increase in osteitis pubis in patients with femoroacetabular impingement supports the clinical link between these 2 processes. [Orthopedics. 2016; 39(3):e417-e422.].

Femoral Head Avascular Necrosis Is Not Caused by Arthroscopic Posterolateral Femoroplasty

This study was conducted to identify the risk of avascular necrosis of the femoral head after arthroscopic femoroplasty extending to the posterolateral femoral neck, the source of the primary blood supply to the femoral head. Cam lesions of femoroacetabular impingement are typically anterior along the junction of the femoral head and neck. However, anatomic variations can involve the posterolateral vascular region of the femoral head and neck. Femoroplasty involving this vascular region can lead to injury to the blood supply to the femoral head, with subsequent avascular necrosis. If the posterolateral portion of the cam lesion is preserved, persistent femoroacetabular impingement may occur. A retrospective review identified 112 patients who underwent arthroscopic femoroplasty for femoroacetabular impingement over a 2-year period. Of these patients, 14 had femoroplasty that extended to the posterolateral femoral head. Of this group, 5 had undergone magnetic resonance imaging (MRI) after femoroplasty and the other 9 were contacted to undergo MRI of the hip to evaluate for avascular necrosis. A radiologist and the senior author evaluated all MRI scans specifically for avascular necrosis of the femoral head. All procedures were performed by the senior author. Mean age of the 14 patients (8 women and 6 men) with femoroplasty that extended into the posterolateral vascular region of the femoral head was 44 years (range, 23-69 years). All 14 patients underwent MRI evaluation of the affected hip a mean of 25 months (range, 7-44 months) after femoroplasty. No MRI scans showed evidence of avascular necrosis of the femoral head. Femoroplasty of the posterolateral vascular region of the femoral head is not associated with avascular necrosis. Patients with femoroacetabular impingement and a cam lesion extending to the posterolateral femoral head can undergo femoroplasty of this region without the development of avascular necrosis. [Orthopedics. 2016; 39(3):177-180.].

Hip arthroscopy in osteoarthritis consequent to FAI

BACKGROUND

Femoral Acetabular Impingement (FAI) means a set of alterations involving the acetabulum, proximal femur, or both of these components that can results in osteoarthritis. Arthroscopy is a choice for the treatment of initial stages of osteoarthritis (OA) in order to reduce evolution of the degenerative processes; advanced degrees of osteoarthritis are absolute contraindications.

MATERIALS AND METHODS

40 patients affected by osteoarthritis in FAI  underwent hip arthroscopy between May 2010 and March 2015. In all 40 cases OA secondary to FAI was diagnosed. All patients were clinically and instrumentally analyzed pre-operatively and then post-operatively after 3, 6, and 12 months. We evaluated the degree of OA using the Tonnis classification; our study included only patients affected by Tonnis grade 0-2 osteoarthritis.

RESULTS

The mean modified Harris Hip Score showed an evolution from 54.7 points to an average value of 89,1 points after 12 months. The Lower Extremities Functional Scale evolved by 43 points to an average value of 65,28 points.

CONCLUSIONS

Based on the data of this study, supported by the concordance with recent literature reviews, in degrees Tonnis 0 and 1 an arthroscopic treatment is recommended. Instead the therapeutic algorithm in Tonnis grade 2 is still being discussed. We detect a significant response to arthroscopic intervention which leads us to suggest that validation of this method needs further confirmatory studies.

Atypical hip pain: coexistence of femoroacetabular impingement (FAI) and osteoid osteoma

The objective of this article was to emphasize the importance of including less common causes of hip pain in a differential diagnosis, particularly when clinical and radiographic variables are atypical. This article presents the case of a 52-year-old patient with a history of progressive hip pain resulting from the coexistence of both a femoroacetabular impingement (FAI) and an intraarticular osteoid osteoma. The intraarticular osteoid osteoma was initially overlooked due to its unremarkable features on radiographic and resonance imaging. Consequently, the patient was surgically treated for FAI with only partial relief. An osteolytic nidus characteristic of osteoid osteoma was discovered only 1.5 years following surgery. The patient was subsequently treated for osteoid osteoma with anti-inflammatories, after which his pain began to resolve. The patient was completely pain free after 7 months. Level of evidence V.

Biochemical MRI predicts hip osteoarthritis in an experimental ovine femoroacetabular impingement model

BACKGROUND

Cam-type femoroacetabular impingement (FAI) resulting from an abnormal nonspherical femoral head shape leads to chondrolabral damage and is considered a cause of early osteoarthritis. A previously developed experimental ovine FAI model induces a cam-type impingement that results in localized chondrolabral damage, replicating the patterns found in the human hip. Biochemical MRI modalities such as T2 and T2* may allow for evaluation of the cartilage biochemistry long before cartilage loss occurs and, for that reason, may be a worthwhile avenue of inquiry.

QUESTIONS/PURPOSES

We asked: (1) Does the histological grading of degenerated cartilage correlate with T2 or T2* values in this ovine FAI model? (2) How accurately can zones of degenerated cartilage be predicted with T2 or T2* MRI in this model?

METHODS

A cam-type FAI was induced in eight Swiss alpine sheep by performing a closing wedge intertrochanteric varus osteotomy. After ambulation of 10 to 14 weeks, the sheep were euthanized and a 3-T MRI of the hip was performed. T2 and T2* values were measured at six locations on the acetabulum and compared with the histological damage pattern using the Mankin score. This is an established histological scoring system to quantify cartilage degeneration. Both T2 and T2* values are determined by cartilage water content and its collagen fiber network. Of those, the T2* mapping is a more modern sequence with technical advantages (eg, shorter acquisition time). Correlation of the Mankin score and the T2 and T2* values, respectively, was evaluated using the Spearman's rank correlation coefficient. We used a hierarchical cluster analysis to calculate the positive and negative predictive values of T2 and T2* to predict advanced cartilage degeneration (Mankin ≥ 3).

RESULTS

We found a negative correlation between the Mankin score and both the T2 (p < 0.001, r = -0.79) and T2* values (p < 0.001, r = -0.90). For the T2 MRI technique, we found a positive predictive value of 100% (95% confidence interval [CI], 79%-100%) and a negative predictive value of 84% (95% CI, 67%-95%). For the T2* technique, we found a positive predictive value of 100% (95% CI, 79%-100%) and a negative predictive value of 94% (95% CI, 79%-99%).

CONCLUSIONS

T2 and T2* MRI modalities can reliably detect early cartilage degeneration in the experimental ovine FAI model.

CLINICAL RELEVANCE

T2 and T2* MRI modalities have the potential to allow for monitoring the natural course of osteoarthrosis noninvasively and to evaluate the results of surgical treatments targeted to joint preservation.

[Hip dysplasia]

Hip dysplasia and femoroacetabular impingement are frequent causes of hip pain and can often be treated with joint preserving surgery to prevent secondary osteoarthritis (OA). Patient education, progressive resistance training and weight loss at a BMI > 27 kg/m(2) has documented effect on pain and function in primary hip OA. If wound infection occurs after total hip arthroplasty the patient should not be treated with peroral antibiotics but instead be referred to an orthopaedic surgeon. There is no documentation that post-operative movement restrictions prevent dislocation of hip after total hip arthroplasty.

A review of outcomes of the surgical management of femoroacetabular impingement

INTRODUCTION

Femoroacetabular impingement (FAI) resulting from abnormal contact between the acetabulum and femur has been studied extensively in recent years owing to its association with acetabular labrum tears and possible contribution to the development of osteoarthritis.

METHODS

A comprehensive PubMed, MEDLINE(®) and Embase™ literature search was conducted. Search terms included 'femoroacetabular impingement', 'pathophysiology', 'diagnosis', 'dGEMRIC', 'arthroscopic', 'open', 'mini-open' and 'outcome measure'.

RESULTS

A range of radiographic features have been described, and computed tomography and magnetic resonance imaging are both commonly used in the diagnosis of the bony abnormalities in FAI. Treatment of FAI is surgical with methods of treatment ranging from open surgical hip dislocation to arthroscopic osteochondroplasty.

CONCLUSIONS

In recent years, a trend towards the use of arthroscopic treatment for FAI has been seen, with promising results from a range of studies. However, only short-term outcome data are available and a range of different outcome measures have been used in studies to date. We present an overview of the outcomes for a range of surgical treatment methods for FAI and discuss the outcome measures used.

Hip pain in the young, active patient: surgical strategies

Hip disorders in young patients likely exist as a spectrum of prearthritic and arthritic conditions. With the increasing recognition of these disorders, surgical options are being popularized and more patients are being treated at a younger age. Hip surgeons must develop a careful set of evidenced-based indications and follow surgical outcomes in a rigorous, scientific manner. Hip arthroscopy can be used to successfully treat some hip disorders, including labral tears, with or without femoroacetabular impingement, resulting in mechanical symptoms. Long-term outcomes after arthroscopy are determined by the condition of the cartilage at the time of surgery. Patients with preoperative radiographic evidence of moderate to severe arthritis have poor outcomes when treated with arthroscopy. Open joint preservation procedures (including periacetabular osteotomy and surgical hip dislocation with osteochondroplasty) can be done in the absence of substantial arthritis to treat hip dysplasia, femoroacetabular impingement, and related conditions. The results of these procedures are good in appropriately selected patients at short-term to midterm follow-ups. In the presence of severe arthritis, joint replacement is the treatment of choice. Total hip arthroplasty using uncemented acetabular and femoral fixation provides reliable osseointegration; however, long-term results in young patients have historically been compromised by bearing surface wear, osteolysis, and component loosening. Contemporary, highly cross-linked polyethylene and ceramic-on-ceramic bearings have durable results, low complication rates, and offer the potential of long-term survivorship in this high-demand population. In general, metal-on-metal implants have higher complication rates versus other bearing surface options and should be avoided. The best results of hip resurfacing are seen in men younger than 55 years with large femoral head sizes. Although implant survivorship is comparable to that of total hip arthroplasty, the sequelae of metal wear debris continue to cause concern.

Valgus hip with high antetorsion causes pain through posterior extraarticular FAI

BACKGROUND

Valgus hips with increased antetorsion present with lack of external rotation and posterior hip pain that is aggravated with hip extension and external rotation. This may be the result of posterior femoroacetabular impingement (FAI).

QUESTIONS/PURPOSES

We asked whether (1) the range of motion (ROM); (2) the location of anterior and posterior bony collision zones; and (3) the prevalence of extraarticular impingement differ between valgus hips with increased antetorsion compared with normal hips and hips with idiopathic FAI.

METHODS

Surface models based on CT scan reconstructions of 13 valgus hips with increased antetorsion, 22 hips with FAI, and 27 normal hips were included. Validated three-dimensional collision detection software was used to quantify the simulated hip ROM and the location of impingement on the acetabular and the femoral sides.

RESULTS

Hips with coxa valga and antetorsion showed decreased extension, external rotation, and adduction, whereas internal rotation in 90° of flexion was increased. Impingement zones were more anteroinferior on the femur and posteroinferior on the acetabular (pelvic) side; and the zones were more frequently extraarticular, posterior, or to a lesser degree anterior against the inferior iliac spine. We found a higher prevalence of extraarticular impingement for valgus hips with increased antetorsion.

CONCLUSIONS

Valgus hips with increased antetorsion predispose to posterior extraarticular FAI and to a lesser degree anteroinferior spine impingement.

Shared morphology of slipped capital femoral epiphysis and femoroacetabular impingement in early-onset arthritis

A subclinical form of slipped capital femoral epiphysis (SCFE) can lead to subtle morphologic abnormalities, such as cam-type femoroacetabular impingement (FAI). Femoroacetabular impingement is a mechanical hip abnormality that typically affects young populations and leads to hip pain and premature osteoarthritis. Imaging is critical to diagnosis, whether by radiograph, magnetic resonance imaging, or computed tomography. The authors investigated the use of imaging to detect characteristics of subclinical SCFE and cam-type FAI in patients undergoing hip resurfacing. They retrospectively assessed computed tomography scans of 81 hips from 75 patients. Measurements were taken of the proximal femur and included the alpha angle, head-neck tilt, and anterior offset taken in both the conventional oblique axial plane and the radial plane. The cohort consisted of 68 men and 13 women with an average age of 52 years. Ninety percent of hips on the oblique axial view and 95% of hips on the radial view were found to have pathologically increased alpha angles. Negative correlations were found between the alpha angle and head-neck tilt and positive correlations between head-neck tilt and anterior offset ratio. Sixty percent and 68% of hips in the oblique axial and radial planes, respectively, were abnormal for the alpha angle, head-neck tilt, and anterior offset ratio, strongly suggesting SCFE morphology. This study's results show similarity in morphology between cam-type FAI and SCFE, known precursors to osteoarthritis, in an early arthritic patient population.

Effects of posterior pelvic tilt on anterior instability in total hip arthroplasty: a parametric experimental modeling evaluation

BACKGROUND

Anterior dislocation is one of the concerns of patients with posterior pelvic tilt undergoing total hip arthroplasty. This study aimed to evaluate the magnitude of posterior pelvic tilt constituting a risk for anterior dislocation by measuring the range of motion until impingement and dislocation under various pelvic tilt.

METHODS

Using a jig mounted prosthetic hip model, the ranges of external rotation at extension and internal rotation at flexion until reaching dislocation were tested. The site of impingement prior to dislocation was also recorded. Posterior pelvic tilt and the cup version were changed with 10° increments from 0° to 40° and from 10° retroversion to 30° anteversion, respectively. Effects of increasing femoral offset were also tested. We defined a required range of motion as having 30° external rotation at extension and 40° internal rotation at 90° flexion.

FINDINGS

External rotation decreased in a posterior pelvic tilt-dependent manner. In the case with more than 20° posterior pelvic tilt, available external rotation extended beyond required range with the cup anteversion of 20°. Decreasing cup anteversion improved external rotation, however, internal rotation decreased simultaneously. In the case with posterior pelvic tilt more than 20°, only cup anteversion with 0° or 10° satisfied the required range of motion. A +4 mm horizontal offset improved external rotation by 10° with delaying bony impingement.

INTERPRETATION

More than 20° of posterior pelvic tilt may cause anterior instability and diminish the optimal range of cup version. Increasing the femoral offset improved external rotation without reducing internal rotation.

Advances in hip preservation after slipped capital femoral epiphysis

The metaphyseal deformity, in even a mild slipped capital femoral epiphysis (SCFE), results in acetabular labral and cartilage injury. SCFE is the most extreme form of femoroacetabular impingement, and the mechanism of cartilage and labral injuries is similar. Recent surgical advances for treating femoroacetabular impingement have made it possible to consider applying these techniques to the surgical treatment of SCFE deformities to lessen the risk of secondary osteoarthritis. The goals of treatment are to arrest slip progression and restore normal proximal femoral anatomy, thereby decreasing damage to the hip joint secondary to impingement. In situ pinning is the most effective treatment to halt short-term slip progression; outcomes are favorable in many hips. In medical centers with substantial experience with hip preservation techniques, open or arthroscopic osteochondroplasty can be used to treat mild SCFE, and a modified Dunn epiphyseal reorientation can be used for more severe deformities to decrease the potential for secondary osteoarthritis.

The aspherical human hip: implication for early osteoarthritis

One marker for early-onset hip arthritis is femoral acetabular impingement. The current standard way of quantifying impingement is manual calculation of anatomical measures on plain radiographs, including the α-angle. Such measurements are user-dependent and prone to error. We provided a robust computational alternative and proposed using numerical fitting of geometrical shapes. We applied least-squares fitting of an ellipse to the femoral head contour and used the difference between the ellipse axes as a quantification method. The results showed a good correlation between the new measure and previous definitions of the α-angle.

Patterns of joint damage seen on MRI in early hip osteoarthritis due to structural hip deformities

OBJECTIVE

The aim of this study was to evaluate differences in damage patterns assessed using magnetic resonance imaging (MRI) between hips with femoroacetabular impingement (FAI) and developmental dysplasia of the hip (DDH) as well as to correlate MRI findings with delayed Gadolinium enhanced MRI of cartilage (dGEMRIC) and with patient pain.

DESIGN

This retrospective study included 40 patients (mean age 28.6 ± 11.2 years) who underwent dGEMRIC and morphological MRI of the hip. Twenty-one hips with FAI and 19 with DDH were investigated. A self-developed morphological grading (MRI score) and dGEMRIC evaluation were done on seven radial reformats obtained from an isotropic 3D True-fast imaging with steady state precession (FISP) sequence and an isotropic T1-mapping sequence. The observed damage patterns were summed up into sub-scores and a total MRI score.

RESULTS

Labrum damage, paralabral cysts, and acetabular rim bone cysts were more common in DDH patients than in FAI patients. No significant differences were seen in the occurrence of cartilage damage, bone cysts, or osteophytes. In DDH (but not in FAI), the dGEMRIC index demonstrated a tendency for lower values in areas next to cartilage defects. There was no association between labrum damage and dGEMRIC index. A moderate correlation was seen between Western Ontario and McMaster Universities (WOMAC) pain score and cartilage damage, paralabral cysts, and the total MRI score.

CONCLUSIONS

This study confirms a higher prevalence of labrum damage but not cartilage damage in patients with DDH in comparison to patients with FAI. In addition, our data suggests an association of cartilage damage and paralabral cysts with patient reported pain.

[The relationship between chronic hip pain and femoroacetabular impingement: an evaluation with clinical signs and radiography]

OBJECTIVES

In this study, we investigated the rate of the clinical and radiographic findings of femoroacetabular impingement (FAI) in patients with chronic hip pain and compared the findings with those of a control group.

PATIENTS AND METHODS

The clinical and radiographic findings of FAI in 38 patients (group 1) having hip pain for more than three months were analyzed and compared with 42 controls (group 2). Internal rotation degrees were measured while the hips were at 90° flexion and impingement test was performed by rotating the hips internally at 90° flexion and adduction. The FAI findings were investigated on anteroposterior pelvis radiographs and cross-table lateral radiographs of the hip joint in both groups. The collum-diaphyseal angle, alpha angle and anterior offset ratio on the femoral side and the center-edge angle, acetabular index, extrusion index and crossover sign on the acetabular side were evaluated.

RESULTS

The internal rotation degree of the painful hips were less than 20 degree in 18 (47.4%) patients in group 1 and in one (2.4%) patient in group 2 (p<0.001). The impingement sign was positive in 15 (39.5%) patients in group 1 and in one (2.4%) patient in group 2 (p<0.001). While the rate of radiographic findings that can cause pincer type FAI were same in both groups, the rate of patients with radiographic findings that can cause cam type FAI was 76.3% (n=29) in group 1 and 42.9% (n=18) in group 2 (p=0.002).

CONCLUSION

Femoroacetabular impingement is one of the causes of chronic hip pain and if evaluated with suitable clinical and radiographic parameters, the rates of diagnosis may increase.