FAI – Konzept und Ätiopathogenese

Hip Pain and Movement Dysfunction Associated With Nonarthritic Hip Joint Pain: A Revision

The Academy of Orthopaedic Physical Therapy (AOPT), formerly the Orthopaedic Section of the American Physical Therapy Association (APTA), has an ongoing effort to create evidence-based practice guidelines for orthopaedic physical therapy management of patients with musculoskeletal impairments described in the World Health Organization's International Classification of Functioning, Disability, and Health (ICF). This is an update to the 2014 Clinical Practice Guideline (CPG) for Hip Pain and Movement Dysfunction Associated with Nonarthritic Hip Joint Pain. The goals of the revision were to provide a concise summary of the contemporary evidence since publication of the original guideline and to develop new recommendations or revise previously published recommendations to support evidence-based practice. This current CPG covers pathoanatomical features, clinical course, prognosis, diagnosis, examination, and physical therapy interventions in the management of nonarthritic hip joint pain. J Orthop Sports Phys Ther 2023;53(7):CPG1-CPG70. doi:10.2519/jospt.2023.0302.

Proximal femoral epiphyseal spurs and their association with acetabular labral tears on MRI in symptomatic patients

OBJECTIVE

Femoral epiphyseal spurs are developmental projections that form at the edge of the physis. Although considered incidental, their association with acetabular labral tears has never been examined. Our aim was to assess the prevalence of femoral epiphyseal spurs in symptomatic patients with mechanical hip pain and explore if they are associated with labral tears on MRI.

MATERIALS AND METHODS

Hip MRI scans performed on a Siemens 3 T MRI using femoroacetabular impingement protocol were retrospectively reviewed. All patients were referred by orthopaedic surgeons for mechanical hip pain. Two musculoskeletal radiologists blinded to initial reports evaluated MRI images for the presence of an epiphyseal spur and acetabular labral changes. A consensus was achieved on all cases by the two readers. The association between epiphyseal spurs and labral changes was assessed using Fisher's exact test.

RESULTS

A total of 115 patients (178 hip MRI scans) were reviewed; the mean age was 28.8 years (SD 7.1). There were 52 females (45.2%) and 63 males (54.8%). There were 115 hips with labral tears (64.6%). Fourteen hips (7.8%) in ten patients (8.7%) demonstrated epiphyseal spurs and all of them showed labral tears (100%). There was statistically significant association between epiphyseal spurs and labral tears on MRI (p value = 0.0024).

CONCLUSION

Femoral epiphyseal spurs were observed in 8.7% of our defined patient population, and all patients with epiphyseal spurs demonstrated labral tears. Epiphyseal spurs should be documented on imaging reports due to their potential association with labral tears. Future research is needed to further delineate and guide management of these entities.

Autologous Chondrocyte Transplantation in Femoroacetabular Impingement Syndrome: Growth and Redifferentiation Potential of Chondrocytes Harvested from the Femur in Cam-Type Deformities

OBJECTIVE

Cam-type femoroacetabular impingement (FAI) syndrome is one of the most frequent reasons for cartilage damage in the hip. Autologous chondrocyte transplantation has proven high success rates in the treatment of focal chondral defects; however, harvesting of chondrocytes in the hip has been reported but not specifically from the region of femoral cam lesions. Therefore, the goal of this study was to analyze the growth and redifferentiation potential of cartilage samples harvested from the cam deformities in patients with FAI.

DESIGN

Cartilage samples were gained from 15 patients with cam-type FAI undergoing arthroscopic femoral cam resection. Healthy (hyaline cartilage of the hip and knee joint, n = 12) and arthritic control groups (degenerative changes in cartilage of the hip joint, n = 8) were also analyzed. Chondrocytes were initially cultured under monolayer, and subsequently under pellet conditions. A comparative representation of the groups was performed by Mankin score classification, immunohistochemistry (IHC) (Col1, Col2, aggrecan), and quantitative reverse transcription-polymerase chain reaction (qRT-PCR) (Col1, Col2, Col10, Sox9, RunX2).

RESULTS

Mankin score of FAI-samples (4.1±3.1, Range 0-10) showed a wide variation but was significant lower (P = 0.0244) when compared with the arthritic control (7.5 ± 2.7, range 4-12). IHC showed an increased deposition of Col2 (P = 0.0002) and aggrecan (P = 0.0261) after pellet culture compared with deposition after monolayer culture in all groups. In qRT-PCR, FAI samples showed after pellet culture increased Col2 (P = 0.0050) and Col10 expression (P = 0.0006) and also Mankin score correlated increasing gene-expression of Col10 (r = 0.8108, P = 0.0341) and RunX2 (r = 0.8829, P = 0.123).

CONCLUSIONS

Cartilage samples of patients with cam-type FAI showed sufficient but heterogeneous composition relating to histological quality and chondrogenic potential. However, harvesting of chondrocytes from the cam lesion might be a valid option especially if a cartilage lesion is noted in a diagnostic arthroscopy and individual preexisting stage of cartilage degeneration and appropriate pellet-culturing conditions are considered.

A Comparison of Clinical Outcome Between Athletes and Nonathletes Undergoing Hip Arthroscopy for Femoroacetabular Impingement

OBJECTIVE

To compare the clinical outcome of arthroscopic surgery for femoroacetabular impingement (FAI) between athlete and nonathlete patients.

DESIGN

Retrospective case-control study. Level of Evidence III.

PATIENTS AND METHODS

Seventy-four patients who underwent arthroscopic FAI correction from March 2009 to April 2012 were enrolled in this study. The patients were divided into 2 groups, according to their sports participation (47 in the athlete group and 27 in the nonathlete group).

MAIN OUTCOME MEASURES

We reviewed clinical and radiographic data for all patients, up to a minimum of 2 years after surgery. We used analysis of covariance to compare the mean patient reported outcome scores including modified Harris hip score (MHHS) and the nonarthritis hip score (NAHS) preoperatively, at 6, 12, and 24 months after surgery.

RESULTS

The mean age at the time of surgery in the athlete group was significantly lower than that in the nonathlete group. Although there was no significant difference in preoperative MHHS and NAHS, the mean NAHS at 6, 12, and 24 months postoperatively and the mean MHHS at 24 months postoperatively in athletes were significantly higher than that in nonathletes (P < 0.05).

CONCLUSIONS

Although arthroscopic FAI correction and labral preservation surgery is generally beneficial, it appears to provide a better clinical outcome in athletes than in nonathletes.

Three-dimensional Imaging and Computer Navigation in Planning for Hip Preservation Surgery

Hip preservation surgery is performed to address femoroacetabular impingement, alleviate any associated pain, and reduce the risk of early onset of osteoarthritis. In the last decade, arthroscopy has become more popular in addressing femoroacetabular impingement, due to its minimally invasive approach. However, poor visualization and limited spatial awareness of the joint make arthroscopy of the hip difficult, resulting in a steep learning curve. This paper reviews the utility and benefits of 3-dimensional imaging and computer navigation and what these tools may add to the preoperative planning stages of hip preservation surgery.

Treatment of pincer-type femoroacetabular impingement

Pincer femoroacetabular impingement (FAI) consists of pathological contact between the acetabular labrum and rim and the femoral head-neck junction. Manifold conditions underlie pincer FAI: anatomical abnormalities, malorientation of the acetabulum, torsional abnormalities of the neck and femoral shaft (these defects can be constitutional, post-traumatic or post-surgical), and involvement in sports characterized by repeated and sudden maximum joint excursions. In a high percentage of cases, pincer FAI is associated with cam FAI. The aims of surgical treatment of pincer FAI are to eliminate the cause of the contact and repair the joint damage; the surgery may be open or arthroscopic, performed with an articular or extra-articular approach. Recently, arthroscopic treatment of FAI had a rapid and widespread diffusion due to the advantages it offers compared with the open technique. Arthroscopic treatment can repair the joint damage and in some cases, characterized by minor deformity, compensate for extra-articular defects. The acetabular labrum must always be preserved and sutured; only in extreme cases can it be sacrificed. Post-operative mobilization must respect the healing time of the labral repair.

A Computed Tomography Study of Gender Differences in Acetabular Version and Morphology: Implications for Femoroacetabular Impingement

PURPOSE

To assess the prevalence of acetabular retroversion in a large population of patients with asymptomatic hips. Furthermore, we sought to identify gender differences in acetabular morphology to address the current thinking that retroversion and pincer-type femoroacetabular impingement (FAI) are more common in women.

METHODS

We retrospectively reviewed morphologic features of acetabula from a consecutive series of trauma-protocol computed tomography scans of patients without pelvis injury. An automated algorithm determined the acetabular rim profile and center of the femoral head, normalized the frontal plane of the pelvis, and calculated version and coverage. We then compared male and female rim profiles, specifically focusing on version and acetabular wall coverage in the 1-o'clock (anterosuperior), 2-o'clock (central), and 3-o'clock (inferior) positions.

RESULTS

Of 1,088 patients in the database, 878 had complete data (i.e., age, ethnicity, and body mass index) and were therefore included in the final analysis. Of these, 34.3% were women and 65.7% were men. Mean global acetabular version was 19.1° for men and 22.2° for women (P < .001). Mean acetabular version for men and women was 15.5° and 18.3°, respectively, in the 1-o'clock position; 21.5° and 24.0°, respectively, in the 2-o'clock position; and 20.2° and 24.3°, respectively, in the 3-o'clock position (P < .001 for all 3). True retroversion (<0°) was observed only in the 1-o'clock position. The prevalence of true acetabular retroversion in the 1-o'clock position for men and women was 4.3% and 3%, respectively (P = .36).

CONCLUSIONS

Mean global and focal acetabular anteversion was greater in women, and the prevalence of focal cephalad retroversion in the 1-o'clock position was not significantly different compared with men. Acetabular retroversion and anterior overcoverage are not more prevalent in women in the anterosuperior acetabulum, where femoroacetabular impingement most commonly occurs.

LEVEL OF EVIDENCE

Level III, diagnostic study.

Validation of the Core Outcome Measures Index in Patients With Femoroacetabular Impingement

PURPOSE

To evaluate a short, hip-oriented outcome instrument, based on the Core Outcome Measures Index (COMI), in patients undergoing surgery for femoroacetabular impingement (FAI).

METHODS

The following full-length questionnaires were completed preoperatively and at 6 and 12 months postoperatively by 159 consecutive FAI patients: Hip Outcome Score (HOS); Oxford Hip Score; Western Ontario and McMaster Universities Arthritis Index; Short Form 12 Health Survey; World Health Organization Quality of Life questionnaire, short version; and EuroQol-Five Dimensional index. The scores for the 6 hip-oriented Core Outcome Measures Index (COMI-Hip) items-addressing pain, function, symptom-specific well-being, quality of life, and disability-were extracted from established full-length questionnaires, and their performance as an index was compared with that of the full-length instruments.

RESULTS

Scores for the single items of the COMI-Hip questionnaire correlated well with the scores for the corresponding full-length instruments from which they were extracted (r = -0.89 to -0.62, P < .001). The COMI-Hip sum score also correlated well with the Oxford Hip Score and the Western Ontario and McMaster Universities Arthritis Index pain and function scores (r = -0.85 to -0.70, P < .001), as well as with the HOS (r = -0.72 to -0.60, P < .001), an instrument specifically developed for assessing FAI patients. Internal responsiveness (Cohen d for effect size) of the COMI-Hip sum score from preoperatively to 12 months postoperatively was similar to that of the HOS activities-of-daily living subscale (d = -0.76 and d = -0.68, respectively; P < .001). Significant correlations were found between the change scores of the COMI-Hip sum score and those of the HOS activities-of-daily living and sport subscales at 6 months (r = -0.62 and r = -0.60, respectively; P < .001) and 12 months (r = -0.69 and r = -0.61, respectively; P < .001), showing the external responsiveness of the COMI-Hip.

CONCLUSIONS

The COMI-Hip is a simple yet valid and responsive outcome instrument for the efficient assessment of patients undergoing surgery for FAI. It performs at least as well as the current reference instrument for FAI, the HOS, and can therefore be considered a potentially valuable instrument for routine use in both research and clinical practice.

LEVEL OF EVIDENCE

Level II, development of diagnostic criteria based on consecutive patients (with universally applied reference gold standard).

Clinical and morphologic factors associated with suture anchor refixation of labral tears in the hip

BACKGROUND

The acetabular labrum is critical to hip function. Surgical options for treatment of a damaged labrum include removal, debridement, and refixation using suture anchors.

QUESTIONS/PURPOSES

The purpose of this study is to determine if certain patient demographic and osseous morphological factors result in increased labral damage requiring refixation.

METHODS

Data was collected prospectively from a consecutive series of 334 procedures performed from August 2010 to June 2011 for femoroacetabular impingement. Demographic data, including age, sex, and race, was collected from patient charts. Three-dimensional (3D) CT scans were reviewed to retrieve alpha angles, acetabular version, femoral version, and lateral center edge angle on the symptomatic hip.

RESULTS

In 238 (71.3%) of the procedures, the labrum required refixation using suture anchors with a mean of 2.74 anchors being used. Of males, 78.8% required suture anchors and 62.3% of females required suture anchors. Among procedures requiring suture anchors, significantly more suture anchors were used in males (2.92) than females (2.47). Regression analysis showed a positive association between alpha angle, acetabular retroversion at 1 and 2 o'clock, and the number of suture anchors used. The mean alpha angle in the cohort that required suture anchors (63.1°) was significantly greater than the cohort that did not (59.4°).

CONCLUSION

This study found femoral deformities to contribute more to labral damage than acetabular deformities and highlighted the importance of preoperative 3D CT scans. This study provides demographic and morphologic factors to review preoperatively to evaluate if extensive labral damage is present and if suture anchor refixation will be required.

Efficacy of Intra-articular Steroid Injection in Patients with Femoroacetabular Impingement

Femoroacetabular Impingement (FAI) arises from morphological abnormalities between the proximal femur and acetabulum. Impingement caused by these morphologic abnormalities induces early degenerative changes in the hip joint. Furthermore, FAI patients complain of severe pain and limited range of motion in the hip, but a guideline for treatment of FAI has not yet been established. Medication, supportive physical treatment and surgical procedures have been used in the treatment of the FAI patients; however, the efficacies of these treatments have been limited. Here, we report the diagnosis and treatment for 3 cases of FAI patients. Intra-articular (IA) steroid injection of the hip joint was performed in all three patients. After IA injection, pain was reduced and function had improved for up to three months.

Fulfilment of patient-rated expectations predicts the outcome of surgery for femoroacetabular impingement

OBJECTIVE

The aim of this study was to explore the role of expectations in relation to patient-rated global treatment outcome in patients undergoing hip preservation surgery for femoroacetabular impingement (FAI).

METHOD

Pre-operatively, 86 patients completed the Oxford Hip Score (OHS), a question about the motivation for undergoing surgery, and Likert-scales rating the improvement expected in various domains (pain, general function, sport, walking capacity, independence, social function, mental well-being). 12-months post-operatively, they rated the actual perceived improvement in each domain and the global outcome of surgery (GTO, 5-point Likert-scale: operation "helped a lot" through to "made things worse"), and completed the OHS again.

RESULTS

The most frequent "top reason" for surgery was "alleviation of pain", being indicated by 33% patients; 20% patients chose "fear of worsening", 16% "improvement in everyday activities", 11% "other therapies failed", 10% "improvement in sporting activities" and 10% other. The 12-month data revealed prior expectations had been overly optimistic in more than 50% patients for hip pain, sport, and general physical capacity, and in 33-45% patients for independence, mental well-being, and walking capacity. Multiple regression revealed significant (P<0.05) unique associations between GTO and "fulfilled expectations" for pain and sport (explaining 47% and 12% variance, respectively).

CONCLUSION

Expectations of surgery were overly optimistic. Having one's expectations fulfilled, especially in relation to pain, was important for a good outcome. The results emphasise the benefit of assessing patient-orientated outcome in routine practice and the factors that might influence it, such that realistic expectations can be established for patients prior to surgery.

Changes in the stress in the femoral head neck junction after osteochondroplasty for hip impingement: a finite element study

The surgical treatment of femoroacetabular impingement (FAI) often involves femoral osteochondroplasty. One risk of this procedure is fracture of the femoral neck. We developed a finite element (FE) model to investigate the relationship between depth of resection and femoral neck stress. CT data were used to obtain the geometry of a typical cam-type hip, and a 3D FE model was constructed to predict stress in the head-neck after resection surgery. The model accounted for the forces acting on the head and abductor muscular forces. Bone resection was performed virtually to incremental resection depths. The stresses were calculated for five resection depths and for five different activities (i) standing on one leg (static case); (ii) two-to-one-to-two leg standing; (iii) normal walking; (iv) walking down stairs; and (v) a knee bend. In general, both the average Von Mises stresses and the area of bone that yielded significantly increased at a resection depth of ≥10 mm. The knee bend and walking down stairs demonstrated the highest stresses. The FE model predicts that fracture is likely to occur in the resection area first following removal of a third (10 mm) or more of the diameter of the femoral neck. We suggest that when surgeons perform osteochondroplasty for hip impingement, the depth of resection should be limited to 10 mm.

The early outcome of surgical treatment for femoroacetabular impingement: success depends on how you measure it

OBJECTIVE

To evaluate the proportion of "successes" after surgery for femoroacetabular impingement (FAI) using different external criteria, "feeling better" and "feeling good", and to determine the corresponding cut-off scores indicating "success" for the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) (0-10-point response scale), Oxford Hip Score (OHS) and EuroQoL-5D (EQ-5D and EQ-VAS).

DESIGN

Prospective, observational study based in an orthopaedic hospital. Ninety-nine consecutive patients with FAI completed the questionnaires before and 6 months after surgery (arthroscopy or mini-open surgical dislocation). Patient-ratings of change in state ("feeling better") were assessed using a global treatment outcome (GTO) item. Acceptability of the current health state was assessed using the symptom-specific well-being (SSWB) item. Cut-off (threshold) scores for the different instruments indicating the minimal clinically important change (MCIC) and acceptable symptom state were calculated using Receiver Operating Characteristics (ROC) analyses.

RESULTS

Significant improvements in all scores (P < 0.001) were recorded 6 months after surgery. The proportion of good outcomes measured with GTO was 60%; 55% of patients reported having achieved an acceptable symptom state. The MCIC scores for improvement were ≥6 for the OHS (0-48 total score range), ≥15 for EQ-VAS, ≥0.16 for EQ-5D index, and ≥22 for the WOMAC-total score (0-100 total score range); absolute scores of ≥40, ≥80, ≥0.682 and ≤8, respectively, were associated with an acceptable symptom state.

CONCLUSIONS

The results show that feeling better does not always equate to feeling good, and that improvements in outcome scores, even large, do not necessarily indicate acceptability of the current state. The cut-off values may help in the interpretation of trial results and individual change-scores recorded in clinical practice.

The Development and validation of a self-administered quality-of-life outcome measure for young, active patients with symptomatic hip disease: the International Hip Outcome Tool (iHOT-33)

PURPOSE

The purpose of this study was to develop a self-administered evaluative tool to measure health-related quality of life in young, active patients with hip disorders.

METHODS

This outcome measure was developed for active patients (aged 18 to 60 years, Tegner activity level ≥ 4) presenting with a variety of symptomatic hip conditions. This multicenter study recruited patients from international hip arthroscopy and arthroplasty surgeon practices. The outcome was created using a process of item generation (51 patients), item reduction (150 patients), and pretesting (31 patients). The questionnaire was tested for test-retest reliability (123 patients); face, content, and construct validity (51 patients); and responsiveness over a 6-month period in post-arthroscopy patients (27 patients).

RESULTS

Initially, 146 items were identified. This number was reduced to 60 through item reduction, and the items were categorized into 4 domains: (1) symptoms and functional limitations; (2) sports and recreational physical activities; (3) job-related concerns; and (4) social, emotional, and lifestyle concerns. The items were then formatted using a visual analog scale. Test-retest reliability showed Pearson correlations greater than 0.80 for 33 of the 60 questions. The intraclass correlation statistic was 0.78, and the Cronbach α was .99. Face validity and content validity were ensured during development, and construct validity was shown with a correlation of 0.81 to the Non-Arthritic Hip Score. Responsiveness was shown with a paired t test (P ≤ .01), effect size of 2.0, standardized response mean of 1.7, responsiveness ratio of 6.7, and minimal clinically important difference of 6 points.

CONCLUSIONS

We have developed a new quality-of-life patient-reported outcome measure, the 33-item International Hip Outcome Tool (iHOT-33). This questionnaire uses a visual analog scale response format designed for computer self-administration by young, active patients with hip pathology. Its development has followed the most rigorous methodology involving a very large number of patients. The iHOT-33 has been shown to be reliable; shows face, content, and construct validity; and is highly responsive to clinical change. In our opinion the iHOT-33 can be used as a primary outcome measure for prospective patient evaluation and randomized clinical trials.

Hip arthroscopy improves symptoms associated with FAI in selected adolescent athletes

BACKGROUND

Femoroacetabular impingement (FAI) is increasingly diagnosed in young and middle-aged patients. Although arthroscopic procedures are becoming frequently used in the treatment of FAI, there are little data regarding rates of complications or the ability of hip arthroscopy to improve hip function specifically in the adolescent athlete population. Because arthroscopic treatment is being used in the treatment of FAI, it is vital to know what, if any, improvements in hip function can be expected and the potential complications.

QUESTIONS/PURPOSES

We asked (1) whether validated measures of hip function improve after arthroscopic treatment of FAI in adolescent athletes, and (2) what complications might be expected during and after arthroscopic treatment of FAI in these patients.

METHODS

We retrospectively reviewed the records of 27 hips in 21 patients 19 years of age or younger who underwent arthroscopic treatment for FAI between 2007 and 2008. From the records we extracted demographic data, operative details, complications, and preoperative and postoperative modified Harris hip scores (HHS) and the Hip Outcome Score (HOS). The minimum followup was 1 year (average, 1.5 years; range, 1-2.5 years).

RESULTS

Modified HHS improved by an average of 21 points, the activities of daily living subset of the HOS improved by an average of 16 points, and the sports outcome subset of the HOS improved by an average of 32 points. All patients' self-reported ability to engage in their preoperative level of athletic competition improved. In 24 hips that underwent cam decompression, the mean alpha-angle improved from 64° ± 16° to 40° ± 5.3° postoperatively.

CONCLUSIONS

We found short-term improvements in HOS and HHS with no complications for arthroscopic treatment of FAI in our cohort of adolescent athletes. We believe arthroscopic treatment of FAI by an experienced hip arthroscopist should be considered in selected patients when treating athletically active adolescents for whom nonoperative management fails.

Trends in femoroacetabular impingement research over 11 years

Femoroacetabular impingement is the abutment between the proximal femur and the rim of the acetabulum. It is a common cause of labral injury that has been identified as an early cause of hip osteoarthritis. The diagnosis of femoroacetabular impingement of the hip is currently well defined in orthopedic surgery but should attract the attention of physicians in other disciplines. Conversely, much less is known about the etiology and natural history of femoroacetabular impingement.The goal of this study was to assess the number of articles published on femoroacetabular impingement over 11 years in orthopedic vs nonorthopedic medical journals, and to evaluate the quality of available evidence. PubMed and OvidSP databases were searched for articles on femoroacetabular impingement published from 1999 to 2009. Articles were characterized by publication type and journal type per year. Regression analysis was used to determine the effect of publication year on number of publications of each type. The search yielded 206 publications on femoroacetabular impingement during the evaluation period. Seventy-two percent were published in orthopedic journals. Overall, the number of publications increased exponentially with time. There was an increase in clinical trials over the course of the study period. However, studies with high-quality evidence were scarce. The increase in data from orthopedic and nonorthopedic disciplines is welcome. Nevertheless, high-quality evidence on femoroacetabular impingement is lacking. We believe the current trend toward evidence-based orthopedic surgery will impact future research on this relatively new disorder.