Trends of hip arthroscopy in the setting of acetabular dysplasia

Hip arthroscopy failure rates: a healthcare database analysis in the United States

With hip arthroscopy cases, there has been a concomitant increase in complications and the need for revision surgery. This study aims to further contribute to the literature regarding hip arthroscopy failure rates and associated patient factors following an index hip arthroscopy procedure. The PearlDiver database was queried for patients who had undergone hip arthroscopy. International Classification of Diseases, 10th Revision, Clinical Modification codes were used to ensure that follow-up was performed on the ipsilateral limb. Hip arthroscopy failure was defined specifically as subsequent ipsilateral total hip arthroplasty (THA) and reoperation, which were examined in all patients that met inclusion criteria. Independent patient variables, including psychiatric comorbidities, preoperative SSRI use, smoking, and obesity, were examined to identify an association with failure rates. A Student t-test, with a significance set at P < 0.05, was used for statistical comparisons of postoperative outcomes. Odds ratios were used to calculate the probability of short-term hip reoperation in patients with the above independent variables. A total of 19 067 hip arthroscopy patients were included in this study. Within 2 years from the index hip arthroscopy, there was an 11.42% failure rate as defined by subsequent reoperation and 7.16% failure rate as defined by revision to THA, with a total revision surgery rate of 18.58%. The most common reoperation procedure was revision femoroplasty (72%). Patients with an active diagnosis of a psychiatric comorbidity in the year leading up to a hip arthroscopy procedure were 1.74 times more likely to require a hip reoperation within 1 year (95% CI, 1.55-1.95).

The Definition of Failure in Hip Arthroscopy May Include Factors Outside of Reoperation: A Systematic Review

Purpose

To perform a systematic review about the varying definitions of "failure" of hip arthroscopy (HA) in the current literature and to provide a recommendation for the standardization of defining failure of HA.

Methods

A systematic search of electronic databases was conducted to identity Level I-IV clinical studies on HA failure published between January 2016 and July 2021 according to Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines. Inclusion criteria consisted of studies of patients who underwent an arthroscopic hip procedure and included a definition of failure. Studies with patients who underwent open hip procedures and non-full-text articles were excluded.

Results

Of 1,290 titles, 85 (6.6%) met inclusion criteria and were analyzed in this review. The most common definition of HA failure used was the need for any subsequent ipsilateral hip surgery (80/85, 94.1%). Among studies that noted reoperation as a cause for failure, conversion to total hip arthroplasty was most frequently cited (66/85, 77.6%) followed by any other reoperation on the ipsilateral hip, including repeat HA, hip resurfacing, and hip periacetabular osteotomy (65/85, 76.5%). Multiple studies used subjective patient-reported outcomes, with use of the modified Harris Hip Score being the most common (17/85, 20%).

Conclusions

There are numerous definitions of the term "failure" of HA used by authors in the peer-reviewed literature. A standardized definition of HA failure should be multifactorial. It may include any unplanned subsequent procedures; patient-reported outcomes with emphasis on minimal clinically important difference, substantial clinical benefit, and/or patient acceptable symptom state values; and the inability to return to normal function or sports.

Level of Evidence

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

The Use of Combined Hip Arthroscopy and Periacetabular Osteotomy for Hip Dysplasia Is Increasing and Has Low Complication Rates

Purpose

To analyze the annual use of hip arthroscopy (HA) and Bernese periacetabular osteotomy (PAO) for the treatment of hip dysplasia (HD), as well as postoperative outcomes, including ipsilateral reoperations.

Methods

International Classification of Diseases, Ninth and Tenth Revision, codes were used to query the PearlDiver Mariner database from January 2010 through January 2022 to identify patients aged 10 to 59 years who had a presenting diagnosis of HD and subsequently underwent (1) HA; (2) PAO; or (3) combined HA and PAO (HA-PAO, defined as PAO on the same day or within 28 days after HA). We analyzed annual rates for each treatment, as well as rates of postoperative emergency visits, readmissions, and 5-year ipsilateral secondary operations (determined via Kaplan-Meier analysis).

Results

There were 32,068 patients who underwent surgical treatment of HD. For HA, PAO, and HA-PAO, there were 29,700, 2,083, and 285 patients, respectively. All operations had the greatest percent-increase from 2015 to 2016. HA and HA-PAO peaked in 2021, whereas PAO peaked in 2019. For HA, PAO, and HA-PAO, most cases were performed in female patients and patients aged 30 to 49 years, 10 to 19 years, and 10 to 29 years, respectively. The 5-year incidence of ipsilateral secondary operations, which include revision HA, PAO, or conversion to total hip arthroplasty, was 9.2% (95% confidence interval 8.6%-9.8%) in the HA group and 6.5% (95% confidence interval 4.1%-8.8%) in the PAO group. Combining HA with PAO resulted in so few secondary operations that Kaplan-Meier analysis was infeasible. The PAO cohort had the greatest 30-day emergency visit and 90-day readmission rates, with infection as the most common cause for readmission.

Conclusions

HA is more frequently performed than PAO for hip dysplasia. HA-PAO is increasing at the greatest rate, demonstrating fewer complications and reoperations.

Level of Evidence

Level III, retrospective comparative trial.

Analysis of Hip Preservation Questions on the Orthopaedic In-Training Examination Over the Past 20 Years

Background

The orthopaedic in-training examination (OITE) is a 275-question test for orthopaedic residents administered annually. As the field of orthopaedics changes, the OITE evolves its content. The incidence of hip preservation-related procedures has increased substantially over the past decade; nonetheless, an analysis of the trends of hip preservation questions on the OITE has not yet been performed.

Purpose/Hypothesis

The purpose of the study was to evaluate the number and type of questions on the OITE related to hip preservation to determine whether trends over time paralleled the increases in hip-related care in clinical practice. It was hypothesized that the frequency of hip preservation questions on the OITE would increase with time.

Study Design

Cross-sectional study.

Methods

Each OITE between 2002 and 2021 was reviewed for questions related to hip preservation. The types of questions included under "hip preservation" were those related to femoroacetabular impingement (FAI), athletic soft tissue injuries of the hip, acetabular labral tears, hip arthroscopy, and surgical management of adult hip dysplasia-excluding arthroplasty. Questions were quantified and categorized by topic, taxonomy level, associated imaging, and cited sources.

Results

There were 30 hip preservation-related questions between 2002 and 2021. Of these, 77% occurred within the past 10 years. Also, 14 questions (47%) had associated images in the question stem-the most common being radiographs (n = 8 questions). The most commonly tested subcategories were FAI (n = 11 questions [37%]), athletic injuries (n = 7 questions [23%]), and anatomy (n = 7 questions [23%]). Over the last 10 years, 97.9% of citations were from journal articles-the most common being the Journal of the American Academy of Orthopaedic Surgeons, Clinical Orthopedics and Related Research, and the American Journal of Sports Medicine.

Conclusion

The frequency of hip preservation-related questions on the OITE has increased with time, reflecting trends in clinical practice.

Team Approach: Hip Preservation Surgery

The evaluation and treatment of adolescents and young adults with hip pain has seen tremendous growth over the past 20 years. Labral tears are well established as a common cause of hip pain but often occur because of underlying bony abnormalities. Femoroacetabular impingement (FAI) and acetabular dysplasia are now well-established causes of hip osteoarthritis and are increasingly treated in the prearthritic stage in hopes of improving symptoms and prolonging the longevity of the native hip. Beyond FAI and acetabular dysplasia, this patient population can present with a complex and variable group of underlying conditions that need to be taken into account. Expertise in the conservative management of this population, including physical therapy, is valuable to maximize the success. Preoperative, surgical, and postoperative decision-making and care in this population is complex and evolving. A comprehensive, multidisciplinary approach to the care of this patient population has been used for over 20 years by our institution with great success. The purpose of this article is to review the "team-based approach" necessary for successful management of the spectrum of adolescent and young adult hip disorders.

Sex-Based Differences in Prevalence, Outcomes, and Complications of Hip Arthroscopy for Femoroacetabular Impingement: A Systematic Review and Meta-analysis

Background

Trends between the sexes have been reported regarding prevalence, patient-reported outcomes (PROs), and complications of hip arthroscopy (HA) for femoroacetabular impingement syndrome (FAIS), yet current results lack consensus.

Purpose

To evaluate sex-based differences after HA for FAIS in (1) prevalence of cam and pincer morphology in FAIS and (2) PROs, pain scores, and postoperative complication rates.

Study Design

Systematic review; Level of evidence, 4.

Methods

The EMBASE, PubMed, and Ovid (MEDLINE) databases were searched from establishment to February 28, 2022, according to PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Included studies had sex-based data on prevalence, outcomes, and complications of HA for FAIS. Reviews and commentaries were excluded. Data were combined, and between-sex differences were analyzed. Meta-analyses using random-effects models were performed when possible. Pooled risk ratios (RRs) and standardized mean differences were calculated.

Results

A total of 74 studies were included (213,059 patients; 132,973 female hips [62.4%] and 80,086 male hips [37.6%]). The mean age was 30.7 ± 7.7 years among male patients and 31.1 ± 7.8 years among female patients. Male patients experienced mixed-type impingement significantly more often (39.4% vs 27.2% for female patients; RR = 0.69 [95% confidence interval [CI], 0.58-0.81]; P < .001), whereas female patients experienced pincer-type impingement more often (50.6% vs 30.8% for male patients; RR = 2.35 [95% CI, 1.14-4.86]; P = .02). Male patients had higher likelihoods of undergoing femoroplasty (89.8% vs 77.4% for female patients; RR = 0.90 [95% CI, 0.83-0.97]; P = .006), acetabuloplasty (67.1% vs 59.3% for female patients; RR = 0.87 [95% CI, 0.79-0.97]; P = .01), or combined femoroplasty/acetabuloplasty (29.2% vs 14.5% for female patients; RR = 0.63 [95% CI, 0.44-0.90]; P = .01). Although female patients showed greater improvements in Hip Outcome Score-Sport-Specific subscale (P = .005), modified Harris Hip Score (P = .006), and visual analog scale pain (P < .001), both sexes surpassed the minimal clinically important difference at 1, 2, and 5 years postoperatively. Female patients had higher complication rates (P = .003), although no sex-based differences were found in total hip arthroplasty conversion rates (P = .21).

Conclusion

Male patients undergoing HA for FAIS had a higher prevalence of mixed-type FAIS while female patients had more pincer-type FAIS. Female patients gained greater improvements in PROs, although both sexes exceeded the minimal clinically important difference, suggesting that both male and female patients can benefit from HA.

Evaluation of mechanistic serum and urine biomarkers for secondary osteoarthritis associated with developmental dysplasia of the hip

Objective

Determine measurable differences for mechanistic urine and serum biomarkers in patients with developmental dysplasia of the hip (DDH) prior to, and following, secondary hip osteoarthritis (OA) when compared to controls.

Design

Urine and serum were collected from individuals with developmental dysplasia of the hip (n = 39), prior to (Pre-OA DDH, n = 32) and following diagnosis of secondary hip OA (Post-OA DDH, n = 7), age-matched Pre-OA controls (n = 35), and age-matched Post-OA controls (n = 12). Samples were analyzed for protein biomarkers with potential for differentiation of hip status through a Mann-Whitney U test with a Benjamini-Hochberg correction.

Results

Several interleukin and degradation related proteins were found to be differentially expressed when comparing DDH-related hip status prior to and following diagnosis of hip OA. In addition, MCP-1 and TIMP-1 were significantly different between younger and older patients in the control cohorts.

Conclusion

These results provide initial evidence for serum and urine protein biomarkers that define clinically relevant stages of symptomatic DDH and its progression to secondary hip osteoarthritis categorized by known mechanisms of disease.

Level of evidence

III.

Outcomes After Concomitant Hip Arthroscopy and Periacetabular Osteotomy: A Systematic Review

Background

Despite several studies' reports on outcomes of concomitant hip arthroscopy and periacetabular osteotomy (PAO), there is a paucity of aggregate data in the literature.

Purpose

To evaluate outcomes and survivorship after concomitant hip arthroscopy and PAO.

Study Design

Systematic review; Level of evidence, 4.

Methods

The PubMed, Cochrane, and Scopus databases were searched in April 2022 using the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. The following keywords were used: (hip OR femoroacetabular impingement) AND (arthroscopy OR arthroscopic) AND (periacetabular osteotomy or rotational osteotomy) AND (outcomes OR follow-up). Of 270 articles initially identified, 10 studies were ultimately included. The following information was recorded for each study if available: publication information; study design; study period; patient characteristics; follow-up time; indications for hip arthroscopy; patient-reported outcomes (PROs); rates of secondary hip preservation surgeries; and rates of conversion to total hip arthroplasty (THA). Survivorship was defined as nonconversion to THA.

Results

The study periods for the 10 included articles ranged from 2001 to 2018. Three studies were level 3 evidence, and 7 studies were level 4 evidence. This review included 553 hips with a mean follow-up of 1 to 12.8 years. All 10 studies listed dysplasia as an indication for surgery. Of 9 studies that reported PRO scores, 7 reported significant improvement after surgery. Studies with a <5-year follow-up reported conversion to THA rates of 0% to 3.4% and overall secondary surgery rates of 0% to 10.3%. Similarly, studies with >5-year follow-up reported conversion to THA rates of 0% to 3% and overall secondary surgery rates of 0% to 10%.

Conclusion

Patients who underwent concomitant hip arthroscopy and PAO reported favorable outcomes, with 7 of the 9 studies that provided PRO scores indicating significant preoperative to postoperative improvement.

Treatment of Coxa Profunda With Open Surgical Hip Dislocation, Rim Resection, Cam Resection, and Labral Reconstruction

Coxa profunda presents a unique challenge in surgical treatment approach given global acetabular overcoverage. Arthroscopic treatment can be fraught with difficulty obtaining hip distraction for safe arthroscopic instrumentation, and limited arthroscopic access may prevent sufficient osseous resection of the excess acetabular rim. Although hip arthroscopy use has increased markedly over the past decades for all types of hip pathology, coxa profunda may represent one unique indication for surgical hip dislocation. This technique describes open surgical hip dislocation, rim resection, femoral osteoplasty, and labral reconstruction using anterior tibialis allograft for coxa profunda with combined-type femoroacetabular impingement syndrome and labral ossification.

Arthroscopic labral repair combined with less invasive open-shelf acetabuloplasty for patients with developmental dysplasia of the hip

Hip arthroscopy has become widely used for intra-articular lesions, such as labral tears and femoral acetabular impingement. However, its use in patients with developmental dysplasia of the hip (DDH) has been controversial and has historically demonstrated mixed results, as acetabular dysplasia may cause instability due to insufficient bony coverage of the femoral head, thus causing excessive stress on the repaired labrum and cartilage. We devised a combined hip arthroscopic labral repair and a less invasive open-shelf procedure using a small skin incision as an anterolateral portal in hip arthroscopy. This novel procedure may improve the stability of the repaired labrum with a bony covering in a minimally invasive manner. Moreover, the shelf procedure can be performed under direct vision in a comparatively safe and precise manner. In total, 13 hips with DDH underwent the procedure for labral tears. All patients were females, with a mean age of 30 years. The mean follow-up period was 33 months. The mean Harris hip score improved from 74.2 to 93.6, and Oxford Hip score improved from 32.4 to 19.3. According to the Tönnis classification, the grade of arthritis preoperatively was grade 0 for nine hips and grade I for four hips. No radiographic progression of osteoarthritis was observed. It is possible that this novel procedure could be an effective treatment for labral tears with DDH and may prevent the early onset of secondary osteoarthritis. In this technical tip, we describe hip arthroscopic labral repair combined with a less invasive open-shelf acetabuloplasty in further detail.

Arthroscopic Treatment of Mild/Borderline Hip Dysplasia with Concomitant Femoroacetabular Impingement-Literature Review

Purpose of Review

This literature review aims to survey the current knowledge about the management FAI in the setting of borderline hip dysplasia.

Recent Findings

With better understanding, hip arthroscopy has recently been advocated for treating mild or borderline hip dysplasia (BDH) with concomitant femoroacetabular impingement (FAI) despite early studies that condemned its use. Recent outcome data have demonstrated that hip arthroscopy is a viable option in BDH, with and without FAI, and has been gaining wider acceptance. Hip arthroscopy can address the concomitant soft tissue and bony intra-articular pathologies and obviate the necessity for other surgeries. Moreover, hip arthroscopy may be used as an adjuvant treatment to other procedures such as a periacetabular osteotomy (PAO).

Summary

Hip arthroscopy for BDH is an evolving procedure with promising short- and mid-term outcomes. The combination of BDH and FAI is becoming recognized as a problem in its own right, requiring dedicated treatment.

Patients With a High Femoroepiphyseal Roof With Concomitant Borderline Hip Dysplasia and Femoroacetabular Impingement Syndrome Do Not Demonstrate Inferior Outcomes Following Arthroscopic Hip Surgery

PURPOSE

The purpose of this study was to compare outcomes after hip arthroscopy for femoroacetabular impingement syndrome (FAIS) in patients with borderline hip dysplasia and hip instability defined radiographically using the femoroepiphyseal acetabular roof (FEAR) index and in patients without radiographic evidence of hip instability.

METHODS

Data from consecutive patients with borderline hip dysplasia (lateral center edge angle between 18˚-25˚) who underwent primary hip arthroscopy between April 2012 and June 2017 for the treatment of FAIS were analyzed. Baseline demographic data, radiographic parameters, preoperative, and 2-year postoperative patient-reported outcome measures were collected. The FEAR index was measured by 3 different observers. Patients with an average FEAR index ≥2˚ were categorized as having radiographic evidence of instability as previously published. The analysis was powered to detect a minimal clinically important difference (MCID) for each outcome score. Statistical analysis was performed as appropriate to compare patients with FEAR index ≥2 and <2°.

RESULTS

A total of 140 patients met the inclusion criteria. The average age and body mass index of included patients was 31.7 ± 13.2 (P < .325) years and 25.1 ± 5.6 kg/m² (P < .862). There were no statistically significant demographic differences between the groups. Nineteen (13.0%) patients were found to have a FEAR index of over 2˚. The FEAR index <2° and FEAR index ≥2° groups had a mean preoperative FEAR index (standard deviation, range) of -7.0 (5.2, -26.8 to 1.9) and 4.8 (2.5, 2.0-11.8), respectively. The interrater intraclass correlation coefficient was 0.96. Postoperative patient-reported outcomes and rates of MCID and patient-acceptable symptomatic state achievement were not statistically different between the radiographically stable and unstable groups. (p>0.05 for all).

CONCLUSION

Patients with borderline hip dysplasia and radiographic evidence of hip instability, as measured by the FEAR index (≥2°), achieve similar improvement in 2-year outcomes compared to those with radiographically stable hips after arthroscopic treatment of FAIS.

CLINICAL RELEVANCE

Retrospective Level III cohort study.

The Global Research Trends and Hotspots on Developmental Dysplasia of the Hip: A Bibliometric and Visualized Study

Background: Developmental dysplasia of the hip (DDH) is a common musculoskeletal disorder in newborns and also one of the most common causes of hip arthritis in women. Many topics concerning DDH still remain controversial, and the global research trend in this field has not been well-studied yet. The aim of the present study was to illustrate the overall knowledge structure, development trends, and research hotspots of DDH.

Methods: The publications related to DDH from 1998 to 2020 were identified from the Web of Science Core Collection (WOSCC). Three bibliometric tools were used to conduct visualization and knowledge maps. Annual trends of publications, contributions of countries, institutions, authors, funding agencies and journals, and clustering of keywords were analyzed.

Results: A total of 2,691 publications were included. The annual number of DDH publications showed an increasing trend worldwide. The United States has made the greatest contribution, with the largest number of publications and the highest H-index. The most prolific institutions were Shanghai Jiao Tong University, Children's Hospital of Philadelphia, and Shriners Hospital for Children. Professors Tönnis D, Harris WH, Crowe JF, Graf R, and Salter RB have made great achievements in this field. However, the collaboration between international institutions or researchers was relatively low and mainly conducted in European and American countries. All the keywords could be divided into five clusters: hip osteoarthritis study, hip replacement study, hip ultrasound study, osteotomy surgery study, and etiology study. A trend of balanced and diversified development existed in these clusters. Keywords with the ongoing bursts, including clinical outcome, risk factor, femoroacetabular impingement, predictor, arthroscopy, morphology, and anteversion may continue to be the research hotspots in the near future.

Conclusions: There will be an increasing number of publications on DDH research, and the United States stay ahead in this field. International collaboration needs to be further strengthened. The information can provide helpful references for researchers to explore hot issues or target a specific field of DDH.

Is a periacetabular osteotomy as efficacious in retroversion as it is in dysplasia? : The role of femoral anteversion on outcome

Aims

Periacetabular osteotomy (PAO) is an established treatment for acetabular dysplasia. It has also been proposed as a treatment for patients with acetabular retroversion. By reviewing a large cohort, we aimed to test whether outcome is equivalent for both types of morphology and identify factors that influenced outcome.

Methods

A single-centre, retrospective cohort study was performed on patients with acetabular retroversion treated with PAO (n = 62 hips). Acetabular retroversion was diagnosed clinically and radiologically (presence of a crossover sign, posterior wall sign, lateral centre-edge angle (LCEA) between 20° and 35°). Outcomes were compared with a control group of patients undergoing PAO for dysplasia (LCEA < 20°; n = 86 hips). Femoral version was recorded. Patient-reported outcome measures (PROMs), complications, and reoperation rates were measured.

Results

The mean Non-Arthritic Hip Score (NAHS) preoperatively was 58.6 (SD 16.1) for the dysplastic hips and 52.5 (SD 12.7) for the retroverted hips (p = 0.145). Postoperatively, mean NAHS was 83.0 (SD 16.9) and 76.7 (SD 17.9) for dysplastic and retroverted hips respectively (p = 0.041). Difference between pre- and postoperative NAHS was slightly lower in the retroverted hips (18.3 (SD 22.1)) compared to the dysplastic hips (25.2 (SD 15.2); p = 0.230). At mean 3.5 years’ follow-up (SD 1.9), one hip needed a revision PAO and no hips were converted to total hip arthroplasty (THA) in the retroversion group. In the control group, six hips (7.0%) were revised to THA. No differences in complications (p = 0.106) or in reoperation rate (p = 0.087) were seen. Negative predictors of outcome for patients undergoing surgery for retroversion were female sex, obesity, hypermobility, and severely decreased femoral anteversion.

Conclusion

A PAO is an effective surgical intervention for acetabular retroversion and produces similar improvements when used to treat dysplasia. Femoral version should be routinely assessed in these patients and when extremely low (< 0°), as an additional procedure to address this abnormality may be necessary. Females with signs of hypermobility should also be consulted of the likely guarded improvement.

Cite this article: Bone Jt Open 2021;2(9):757–764.

Can the Femoro-Epiphyseal Acetabular Roof (FEAR) Index Be Used to Distinguish Dysplasia from Impingement?

BACKGROUND

Classifying hips with structural deformity on the spectrum from impingement to dysplasia is often subjective and frequently inexact. Currently used radiographic measures may inaccurately predict a hip's morphological stability in borderline hips. A recently described radiographic measure, the Femoro-Epiphyseal Acetabular Roof (FEAR) index, has demonstrated an ability to predict stability in the borderline hip. This measure is attractive to clinicians because procedures can be used on the basis of a hip's pathomechanics. This study was designed to further validate and characterize the FEAR index in a skeletally immature population, in hips with dysplasia/femoroacetabular impingement (FAI), and in asymptomatic hips.

QUESTIONS/PURPOSES

(1) What are the characteristics of the FEAR index in children and how does the index change with skeletal maturation? (2) How does the FEAR index correlate with clinical diagnosis and surgical treatment in a large cohort of symptomatic hips and asymptomatic controls? (3) How does the FEAR index correlate with clinical diagnosis in the borderline hip (lateral center-edge angle [LCEA] 20°-25°) group?

METHODS

A total of 220 participants with symptomatic investigational hips with a clinical diagnosis of dysplasia or FAI between January 2008 and January 2018 were retrospectively collected from the senior author's practice. Investigational hips were excluded if they had any femoral head abnormalities preventing LCEA measurement (for example, Perthes disease), Tönnis osteoarthritis grade greater than 1, prior hip surgery, or prior femoral osteotomy. In the 220 participants, 395 hips met inclusion criteria. Once exclusion criteria were applied, 15 hips were excluded due to prior hip surgery or prior femoral osteotomy, and 12 hips were excluded due to femoral head deformity. A single hip was then randomly selected from each participant, resulting in 206 investigational hips with a mean age of 13 ± 3 years. Between January 2017 and December 2017, 70 asymptomatic control participants were retrospectively collected from the senior author's institutional trauma database. Control hips were included if the AP pelvis film had the coccyx centered over the pubic symphysis and within 1 to 3 cm of the superior aspect of the symphysis. Control hips were excluded if there was any fracture to the pelvis or ipsilateral femur or the participant had prior hip/pelvis surgery. After exclusion criteria were applied, 16 hips were excluded due to fracture. One hip was then randomly selected from each participant, resulting in 65 control hips with a mean age of 16 ± 8 years. Standardized standing AP pelvis radiographs were used to measure the FEAR index, LCEA, and Tönnis angle in the investigational cohort. Standardized false-profile radiographs were used to measure the anterior center-edge angle (ACEA) in the investigational cohort. Two blinded investigators measured the FEAR index with an intraclass correlation coefficient of 0.92 [95% CI 0.84 to 0.96]. Question 1 was answered by comparing the above radiographic measures in age subgroups (childhood: younger than 10 years; adolescence: 10 to 14 years old; maturity: older than 14 years) of dysplastic, FAI, and control hips. Question 2 was answered by comparing the radiographic measures in all dysplastic, FAI, control hips, and a subgroup of operatively or nonoperatively managed dysplasia and FAI hips. Question 3 was answered by comparing the radiographic measures in borderline (LCEA 20°-25°) dysplastic, FAI, and control hips.

RESULTS

The FEAR index was lower in older dysplastic of hips (younger than 10 years, 6° ± 9°; 10 to 14 years, 4° ± 10°; older than 14 years, 5° ± 9°; p < 0.001) and control hips (younger than 10 years, -6° ± 5°; 10 to 14 years, -15° ± 4°; older than 14 years, -16° ± 7°; p < 0.001). The diagnosis and age groups were independently correlated with the FEAR index (p < 0.001). The relationship between the FEAR index and diagnosis remained consistent in each age group (p = 0.11). The FEAR index was higher in all dysplastic hips (mean 5° ± 10°) than in asymptomatic controls (mean -13° ± 7°; p < 0.001) and FAI hips (mean -10° ± 11°; p < 0.001). Using -1.3° as a cutoff for FAI/control hips and dysplastic hips, 81% (112 of 139) of hips with values below this threshold were FAI/control, and 89% (117 of 132) of hips with values above -1.3° were dysplastic. The receiver operator characteristics area under the curve (ROC-AUC) was 0.91. Similarly, the FEAR index was higher in borderline dysplastic hips than in both asymptomatic borderline controls (p < 0.001) and borderline FAI hips (p < 0.001). Eighty-nine percent (33 of 37) of hips with values below this threshold were FAI/control, and 90% (37 of 41) of hips with values above -1.3° were dysplastic. The ROC-AUC for borderline hips was 0.86.

CONCLUSION

The FEAR index was associated with the diagnosis of hip dysplasia and FAI in a patient cohort with a wide age range and with varying degrees of acetabular deformity. Specifically, a FEAR index greater than -1.3° is associated with a dysplastic hip and a FEAR index less than -1.3° is associated with a hip displaying FAI. Using this reliable, developmentally based radiographic measure may help hip preservation surgeons establish a correct diagnosis and more appropriately guide treatment.

LEVEL OF EVIDENCE LEVEL

III, diagnostic study.

Making Sense of Hip Preservation Procedural Coding-Getting Paid for Your Work!

Hip preservation and peri-trochanteric procedures are becoming more commonplace for the arthroplasty surgeon. Understanding the reimbursement for these procedures remains a challenge for those looking to expand this portion of their practice. In order to financially maximize the surgeon’s efforts, we present recommendations for hip preservation procedural coding.

Bernese periacetabular osteotomy: functional outcomes in patients with untreated intra-articular lesions

Developmental dysplasia of the hip (DDH) has been recognized to be a condition leading to osteoarthritis. Periacetabular osteotomy (PAO) has showed good results on hip preservation treatment for these cases. Nevertheless, intra-articular damage may be responsible for persistent post-operative symptoms, so treat the articular damage before or during the PAO has emerged as an alternative to address it. The objective is to identify the prevalence of intra-articular damage, functional outcomes of patients undergoing PAO with untreated intra-articular lesions and the survivorship free total hip arthroplasty (THA) at long-term follow-up. A retrospective review of 103 hips in 92 patients, mean age 26 years old (19–31), 96% females. Mean follow-up 7 years (range: 3–16). Intra-articular damage was evaluated with high-resolution magnetic resonance imaging (MRI) previous to perform the PAO, the chondral damage was evaluated using International Cartilage Repair Society classification. Harris Hip Score (HHS) was obtained in all patients. One hundred per cent of the cases had labral tears on MRI, hypertrophic labrum in 80.8% and paralabral cysts in 20.8%. Acetabular chondral damage was Grade 2 in 88.5% of the hips. HHS was good and excellent in 94%. Survivorship free of THA at 15 years was 87%. Chondrolabral damage is a common finding in patients with DDH. Despite that, excellent results are obtained with PAO without labral repair. We think the focus should be in the biomechanical and anatomical correction of the hip in patients with DDH.

Periacetabular Osteotomy as a Salvage Procedure: Early Outcomes in Patients Treated for Iatrogenic Hip Instability

BACKGROUND

A periacetabular osteotomy (PAO) can reduce pain and improve quality of life in patients with hip dysplasia. While its utility for patients without traditional radiographic parameters for hip dysplasia has not been previously established, the PAO may help treat patients with hip instability that does not improve following single or multiple hip arthroscopic procedures, or when such procedures lead to hip instability.

METHODS

A single-surgeon registry of patients at a single institution was queried to identify patients with a lateral center-edge angle (LCEA) of ≥24° and a Tönnis angle of <10° who underwent PAO because of hip pain and/or instability that failed treatment with hip arthroscopy. Descriptive summary statistics were reported on patient demographics, mean change in LCEA, and patient-reported outcome measures, including the modified Harris hip score (mHHS) and the International Hip Outcome Tool-33 (iHOT-33), at a minimum of 6 months of follow-up.

RESULTS

Among 25 patients (mean age, 27.3 ± 6.9 years; 100% women), the mean LCEA increased from 27.2° (range, 24° to 37°) preoperatively to 39.0° ± 5.1° postoperatively (net increase, 11.8° ± 4.5°). Overall, the mean improvement in the mHHS was 11.5 ± 16.9 (preoperative, 59.4 ± 11.6; postoperative, 70.9 ± 20.6) and the mean improvement in the iHOT-33 was 23.8 ± 23.6 (preoperative, 32.2 ± 17.2; postoperative, 56.0 ± 30.0). Eighteen patients (72%) achieved a minimal clinically important improvement in mHHS (mean improvement, 17.4 ± 12.9) and iHOT-33 (mean improvement, 32.4 ± 19.1) scores. In comparison with 7 patients who did not show improvement, the 18 patients who showed improvement had significantly greater mean baseline patient-reported outcome scores.

CONCLUSIONS

To our knowledge, these findings provide the first report on outcomes of PAO in patients with hip pain following arthroscopy who do not meet the traditional criteria for acetabular dysplasia. Early benefits in clinical outcomes suggest a novel surgical indication for PAO as a potential salvage option for selected patients; however, longer-term studies are needed.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Periacetabular osteotomy with or without arthroscopic management in patients with hip dysplasia: study protocol for a multicenter randomized controlled trial

Background

Hip dysplasia is one of the most common causes of hip arthritis. Its incidence is estimated to be between 3.6 and 12.8% (Canadian Institute for Health Information, Hip and knee replacements in Canada, 2017–2018: Canadian joint replacement registry annual report, 2019; Jacobsen and Sonne-Holm, Rheumatology 44:211–8, 2004). The Periacetabular Osteotomy (PAO) has been used successfully for over 30 years (Gosvig et al., J Bone Joint Surg Am 92:1162–9, 2010), but some patients continue to exhibit symptoms post-surgery (Wyles et al., Clin Orthop Relat Res 475:336–50, 2017). A hip arthroscopy, performed using a small camera, allows surgeons to address torn cartilage inside the hip joint. Although both procedures are considered standard of care treatment options, it is unknown whether the addition of hip arthroscopy improves patient outcomes compared to a PAO alone. To delay or prevent future joint replacement surgeries, joint preservation surgery is recommended for eligible patients. While previous studies found an added cost to perform hip arthroscopies, the cost-effectiveness to Canadian Health care system is not known.

Methods

Patients randomized to the experimental group will undergo central compartment hip arthroscopy prior to completion of the PAO. Patients randomized to the control group will undergo isolated PAO. Patient-reported quality of life will be the primary outcome used for comparison between the two treatment groups as measured by The International Hip Outcome Tool (iHOT-33) (Saberi Hosnijeh et al., Arthritis Rheum 69:86–93, 2017). Secondary outcomes will include the four-square step test and sit-to-stand (validated in patients with pre-arthritic hip pain) and hip-specific symptoms and impairment using the HOOS; global health assessment will be compared using the PROMIS Global 10 Score; health status will be assessed using the EQ-5D-5L and EQ VAS questionnaires (Ganz et al., Clin Orthop Relat Res 466:264–72, 2008) pre- and post-operatively. In addition, operative time, hospital length of stay, adverse events, and health services utilization will be collected. A sub-group of patients (26 in each group) will receive a T1rho MRI before and after surgery to study changes in cartilage quality over time. A cost-utility analysis will be performed to compare costs and quality-adjusted life years (QALYs) associated with the intervention.

Discussion

We hypothesize that (1) concomitant hip arthroscopy at the time of PAO to address central compartment pathology will result in clinically important improvements in patient-reported outcome measures (PROMs) versus PAO alone, that (2) additional costs associated with hip arthroscopy will be offset by greater clinical improvements in this group, and that (3) combined hip arthroscopy and PAO will prove to be a cost-effective procedure.

Trial registration

ClinicalTrials.gov NCT03481010. Registered on 6 March 2020. Protocol version: version 3.

Radiographic and clinical characteristics associated with a positive PART (Prone Apprehension Relocation Test): a new provocative exam to elicit hip instability

Hip instability due to mild dysplasia can be a diagnostic challenge. The physical exam is an important adjunct to radiographic evaluation for the clinical diagnosis of hip instability. Herein, we describe a new maneuver to replicate hip instability pain, called the PART (Prone Apprehension Relocation Test). We retrospectively identified patients in our institution’s hip preservation registry who presented for evaluation of hip pain. We divided patients into ‘positive’ or ‘negative’ PART and analyzed associated clinical and radiographic findings. Ninety patients (159 hips) were included, 83 female and 7 male, average age 27.3 ± 9.1 years. Thirty-four hips (21.4%) had a positive PART. There were no significant differences in hip range of motion, lateral center edge angle, or in acetabular depth. There was, however, a significant difference in acetabular version at 3 o’clock between the two test groups (18.5 ± 6.9° in negative, 21.2 ± 4.9° in positive, P = 0.045). There was no association between PART and previously described anterior apprehension testing. Historical methods of diagnosing hip dysplasia may not adequately identify patients with clinical hip instability. We describe a new provocative exam, the PART, which may be helpful in replicating hip instability symptoms in patients with anterior acetabular undercoverage. PART positive patients had significantly more acetabular anteversion at the 3 o’clock position, which is measured on computed tomography and is not visible on standard anteroposterior (AP) pelvis or false profile radiographs. We believe that the PART is a valuable supplement to clinical examination and radiographic measurements to identify patients with symptomatic hip instability.

Acetabular Morphologic Characteristics Predict Early Conversion to Arthroplasty After Isolated Hip Arthroscopy for Femoroacetabular Impingement

BACKGROUND

Hip arthroscopy in the setting of dysplasia and borderline dysplasia is controversial. Dysplasia severity is most often defined by the lateral center edge angle (LCEA) but can also be evaluated radiographically by the acetabular inclination (AI).

PURPOSE/HYPOTHESIS

The purpose was to determine the effect of AI on outcomes after isolated hip arthroscopy for femoroacetabular impingement (FAI). We hypothesized that patients with dysplasia would have higher rates of arthroplasty as well as inferior clinical and functional outcomes compared with patients who did not have dysplasia.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

A hip arthroscopy registry was reviewed for participants undergoing arthroscopic correction of FAI from February 28, 2008, to June 10, 2013. Participants required a clinical diagnosis and isolated arthroscopic correction of FAI with preoperative imaging and intraoperative cartilage status recorded. AI dysplasia was defined as an AI greater than 10°, LCEA dysplasia as LCEA less than 18°, and borderline LCEA dysplasia as LCEA 18° to 25°. Patients without an acetabular deformity (LCEA 25°-40°; AI <10°) served as a control population. Postoperative variables included patient-reported outcome surveys with conversion to arthroplasty as the primary endpoint. Minimum 5-year outcome scores were obtained for 337 of 419 patients (80.4%) with an average follow-up of 75.2 ± 12.7 months.

RESULTS

This study included 419 patients: 9 (2%) with LCEA dysplasia, 42 (10%) with AI dysplasia, and 51 (12%) with borderline dysplasia. The AI but not LCEA was significantly correlated with lower outcome scores on the modified Harris Hip Score (r = 0.13; P = .01), Non-Arthritic Hip Score (r = 0.10; P = .04), and Hip Outcome Score-Sports Subscale (r = 0.11; P = .04). A total of 58 patients (14%) underwent arthroplasty at 31 ± 20 months postoperatively. Patients with LCEA dysplasia had an arthroplasty rate of 56% (odds ratio, 8.4), whereas patients with AI dysplasia had an arthroplasty rate of 31% (odds ratio, 3.3), which was significantly greater than the rate for the nondysplastic cohort (13.5%; P < .0001). Patients with borderline LCEA dysplasia did not have increased rates of arthroplasty. A multivariate analysis found increasing age, increasing AI, Tönnis grade higher than 1, and femoral Outerbridge grade higher than 2 to be most predictive of conversion to arthroplasty.

CONCLUSION

We found that an elevated AI, along with increasing age, Tönnis grade, and femoral Outerbridge grade significantly predict early conversion to arthroplasty after isolated hip arthroscopy. We recommend using the AI, in addition to the LCEA, in evaluating hip dysplasia before hip arthroscopy.

Is the Femoro-Epiphyseal Acetabular Roof (FEAR) index on MRI a relevant predictive factor of instability in a borderline dysplastic hip?

AIMS

A borderline dysplastic hip can behave as either stable or unstable and this makes surgical decision making challenging. While an unstable hip may be best treated by acetabular reorientation, stable hips can be treated arthroscopically. Several imaging parameters can help to identify the appropriate treatment, including the Femoro-Epiphyseal Acetabular Roof (FEAR) index, measured on plain radiographs. The aim of this study was to assess the reliability and the sensitivity of FEAR index on MRI compared with its radiological measurement.

PATIENTS AND METHODS

The technique of measuring the FEAR index on MRI was defined and its reliability validated. A retrospective study assessed three groups of 20 patients: an unstable group of 'borderline dysplastic hips' with lateral centre edge angle (LCEA) less than 25° treated successfully by periacetabular osteotomy; a stable group of 'borderline dysplastic hips' with LCEA less than 25° treated successfully by impingement surgery; and an asymptomatic control group with LCEA between 25° and 35°. The following measurements were performed on both standardized radiographs and on MRI: LCEA, acetabular index, femoral anteversion, and FEAR index.

RESULTS

The FEAR index showed excellent intraobserver and interobserver reliability on both MRI and radiographs. The FEAR index was more reliable on radiographs than on MRI. The FEAR index on MRI was lower in the stable borderline group (mean -4.2° (sd 9.1°)) compared with the unstable borderline group (mean 7.9° (sd 6.8°)). With a FEAR index cut-off value of 2°, 90% of patients were correctly identified as stable or unstable using the radiological FEAR index, compared with 82.5% using the FEAR index on MRI. The FEAR index was a better predictor of instability on plain radiographs than on MRI.

CONCLUSION

The FEAR index measured on MRI is less reliable and less sensitive than the FEAR index measured on radiographs. The cut-off value of 2° for radiological FEAR index predicted hip stability with 90% probability. Cite this article: Bone Joint J 2019;101-B:1578-1584.

Editorial Commentary: Revision Arthroscopy for Borderline Dysplastic Hips: A Borderline Surgical Indication

Patients with mild or borderline acetabular dysplasia who present with refractory hip pain are challenging patients. Recommending open versus arthroscopic surgery for these patients is a difficult decision, in part because there are conflicting data regarding the outcomes of these procedures. Equally challenging is deciding on a treatment course in a borderline dysplastic patient who has not responded to a previous arthroscopic surgery. Surgeons must give great consideration before recommending revision arthroscopy in this setting.

Functional and Clinical Outcomes of Patients Undergoing Revision Hip Arthroscopy With Borderline Hip Dysplasia at 2-Year Follow-up

PURPOSE

To compare outcomes of borderline hip dysplasia (BHD) patients undergoing revision hip arthroscopy with 1) patients with BHD undergoing primary hip arthroscopy for femoroacetabular impingement syndrome (FAIS) and 2) patients without BHD undergoing revision hip arthroscopy for FAIS.

METHODS

A retrospective cohort study was performed to identify patients who underwent arthroscopy from January 2012 to January 2016 by a single fellowship-trained surgeon, including a 2-year follow-up. Patient demographics, comorbid medical conditions, and preoperative outcome scores were compared between patients with BHD (lateral center-edge angle 18° to 25°) who had revision hip arthroscopy to patients with BHD undergoing primary arthroscopy and patients without BHD (lateral center-edge angle >25°) undergoing revision arthroscopy. Cohorts were matched 2:1 by age and body mass index. Multivariate regressions were used to compare Hip Outcome Score, Activities of Daily Living subscale (HOS-ADL) and Sports subscale (HOS-SS) scores and modified Harris Hip Score (mHHS) between the cohorts at 2-year follow-up. Binomial regression analysis was used to determine predictors of achieving minimal clinically important difference (MCID) and patient-acceptable symptom state (PASS).

RESULTS

There was no statistical difference in age and BMI between the BHD revision (29.1 ± 8.8 years; 25.5 ± 3.58 kg/m²), BHD nonrevision (28.9 ± 8.5 years; 24.6 ± 3.1 kg/m²), and non-BHD revision (29.15 ± 8.6 years; 25.01 ± 3.2 kg/m²) cohorts. There were no statistically significant differences in 2-year clinical outcomes between BHD revision patients and either BHD primary or non-BHD revision patient groups, but BHD revision patients were significantly less likely to achieve PASS for HOS-SS compared with BHD primary and non-BHD revision groups (P = .047 and P = .031, respectively).

CONCLUSION

Surgeons should exercise caution when indicating patients for revision hip arthroscopy with BHD. Although the current study lacks statistical power, the available data suggest that patients undergoing revision surgery with BHD may still experience clinical improvement but be less likely to achieve PASS metrics for several patient-reported outcomes at 2-year follow up.

LEVEL OF EVIDENCE

III, case-control study.