Does the femoral cam lesion regrow after osteoplasty for femoroacetabular impingement? Two-year follow-up

Return to sport after arthroscopic surgery for femoroacetabular impingement

BACKGROUND

Femoroacetabular impingement (FAI) is common among the active and young population. The present study analysed the rate of return to sport, related influencing factors, and the sport activity level according to the Hip Outcome Score - Sport-Specific Subscale (HOS-SSS).

METHODS

The literature search was performed in December 2020. All clinical trials investigating HOS-SSS and/or return to sport after arthroscopic treatment for FAI were considered for inclusion. The outcomes of interest were to analyse the rate of return to sport and the sport activity level according to the HOS-SSS in patients who underwent arthroscopic osteoplasty for FAI.

RESULTS

Data from 41 studies (4063 procedures) were retrieved. A total of 88.75% (581 of 655) of patients returned to sports within a mean of 37.4 ± 16.5 months. The HOS-SSS score improved from 45.0 ± 10.6 to 73.1 ± 9.5 (P < 0.0001) at last follow-up. The following baseline characteristics evidenced positive association with post-operative activity level: lighter weight (P = 0.01), younger age (P = 0.001), Tönnis angle grade I (P = 0.009), greater HHS (P = 0.01), NAHS (P < 0.0001) and HOS-ADL (P = 0.01).

CONCLUSION

Arthroscopic treatment for FAI resulted in excellent results in terms of return to sport. Moreover, lighter weight and younger age, greater HHS, NAHS, HOS-ADL at baseline were positively associated with post-operative sport activity level.

LEVEL OF EVIDENCE

IV, systematic review.

Revision Surgery and Progression to Total Hip Arthroplasty After Surgical Correction of Femoroacetabular Impingement: A Systematic Review

BACKGROUND

Femoroacetabular impingement (FAI) is a major cause of hip pain in young adults and athletes. Surgical treatment of FAI is recommended in cases of failed nonoperative treatment that have the typical clinical and radiographic findings. At present, the role of risk factors for revision surgery and progression to total hip arthroplasty (THA) in patients with FAI is still unclear.

PURPOSE

To investigate the possible association between (1) rate of revision and progression to THA and (2) patient characteristics, type of lesion, family history of hip disease, type of intervention, radiographic parameters, physical examination, and pre- and postoperative scores.

STUDY DESIGN

Systematic review; Level of evidence, 4.

METHODS

The present systematic review was performed according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. In October 2020, the main online databases were accessed. All articles concerning surgical correction for selected patients with FAI were accessed. Patient characteristics, type of intervention, radiographic parameters, physical examination, and pre- and postoperative scores were assessed. The outcomes of interest were the possible association between these variables and the rate of revision and subsequent progression to THA using a multivariate analysis through the Pearson product-moment correlation coefficient.

RESULTS

Data from 99 studies (9357 procedures) were collected. The median follow-up was 30.9 months (interquartile range, 24.0-45.0). The mean ± SD age was 33.4 ± 9.3 years; mean body mass index (BMI), 24.8 ± 4.8; percentage right side, 55.8% ± 8.0%; and percentage female sex, 47.5% ± 20.4%. The overall rate of revision was 5.29% (351 of 6641 patients), while the rate of subsequent progression to THA was 3.78% (263 of 6966 patients). Labral debridement (P < .0001), preoperative acetabular index (P = .01), and BMI (P = .03) all showed evidence of a statistically positive association with increased rates of THA. No other statistically significant associations were found between patient characteristics, type of lesion, family history of hip disease, type of intervention, radiographic parameters, physical examination, or pre- and postoperative scores and the rate of revision and/or progression to THA.

CONCLUSION

Although surgical procedures to treat FAI led to satisfactory outcomes, there was a revision rate of 5.29% in the 9357 procedures in the present systematic review. The rate of progression to THA after a median follow-up of 30 months was 3.78%. Patients who have a higher BMI and/or have a pathologic acetabular index and/or undergo labral debridement during correction of FAI are more at risk for a subsequent THA. We advocate additional education of this patient population in terms of expected outcomes and suggest surgical labral repair instead of debridement if needed.

Arthroscopic Management of Femoroacetabular Impingement in Adolescents: A Systematic Review

BACKGROUND

Femoroacetabular impingement (FAI) is highly prevalent in adolescent athletes. There has been an increasing trend for arthroscopic surgery for FAI, and the results of several clinical studies on outcome after arthroscopic surgery for FAI are available.

PURPOSE

To conduct a systematic review to investigate the role of arthroscopic management for FAI in adolescents.

STUDY DESIGN

Systematic review.

METHODS

This systematic review was conducted according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. In August 2020, PubMed, Scopus, Google Scholar, and EMBASE were accessed. All clinical trials concerning the arthroscopic treatment for adolescents with FAI were identified. Only studies on patients aged less than 18 years at the time of surgery reporting data over a minimum follow-up of 12 months were considered.

RESULTS

Data from 406 adolescents (470 procedures; mean age at surgery, 15.9 years; mean follow-up, 30.4 months) with FAI were retrieved. At a mean of 28.0 months of follow-up, 94% of the adolescents had already returned to sport. All the scores of interest were improved at the final follow-up: visual analog scale (P = .01), modified Harris Hip Score (P < .0001), Non-Arthritic Hip Score (P = .03), Hip Outcome Score-Activities of Daily Living (P = .01), Hip Outcome Score-Sport-Specific Subscale (P < .0001), and Tegner score (P < .0001). Complications occurred in 1.1% (5/470) of procedures, and revision arthroscopy was performed in 4.7% (22/470) of procedures.

CONCLUSION

Arthroscopic surgery in adolescents with FAI achieves excellent outcomes and a high rate of return to sport, with rates of complication and revision surgery of 1% and 5%, respectively.

Outcomes following surgical management of femoroacetabular impingement: a systematic review and meta-analysis of different surgical techniques

Outcomes following different types of surgical intervention for femoroacetabular impingement (FAI) are well reported individually but comparative data are deficient. The purpose of this study was to conduct a systematic review (SR) and meta-analysis to analyze the outcomes following surgical management of FAI by hip arthroscopy (HA), anterior mini open approach (AMO), and surgical hip dislocation (SHD). This SR was registered with PROSPERO. An electronic database search of PubMed, Medline, and EMBASE for English and German language articles over the last 20 years was carried out according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. We specifically analyzed and compared changes in patient-reported outcome measures (PROMs), α-angle, rate of complications, rate of revision, and conversion to total hip arthroplasty (THA). A total of 48 articles were included for final analysis with a total of 4,384 hips in 4,094 patients. All subgroups showed a significant correction in mean α angle postoperatively with a mean change of 28.8° (95% confidence interval (CI) 21 to 36.5; p < 0.01) after AMO, 21.1° (95% CI 15.1 to 27; p < 0.01) after SHD, and 20.5° (95% CI 16.1 to 24.8; p < 0.01) after HA. The AMO group showed a significantly higher increase in PROMs (3.7; 95% CI 3.2 to 4.2; p < 0.01) versus arthroscopy (2.5; 95% CI 2.3 to 2.8; p < 0.01) and SHD (2.4; 95% CI 1.5 to 3.3; p < 0.01). However, the rate of complications following AMO was significantly higher than HA and SHD. All three surgical approaches offered significant improvements in PROMs and radiological correction of cam deformities. All three groups showed similar rates of revision procedures but SHD had the highest rate of conversion to a THA. Revision rates were similar for all three revision procedures.

There is no definite consensus on the adequate radiographic correction in arthroscopic osteochondroplasty for femoroacetabular impingement: a systematic review and meta-analysis

PURPOSE

The purpose of this study is to evaluate and define what is considered an adequate radiographic correction in arthroscopic osteochondroplasty for FAI and to secondarily assess how radiographic outcomes relate to patient reported outcomes and complications.

METHODS

The databases EMBASE, PubMed, and MEDLINE were searched for relevant literature from database inception until January 2021. Studies were screened by two reviewers independently and in duplicate for studies reporting on post-operative radiographic outcomes in arthroscopic osteochondroplasty for FAI. Data on radiographic outcomes as well as data reporting functional outcomes and complications were recorded. A meta-analysis was used to combine the mean pre- and post-operative radiographic outcomes using a random effects model. A risk of bias assessment was performed for all included studies using the MINORS score.

RESULTS

The most commonly reported radiographic outcome was the alpha angle with a pooled mean post-operative angle of 44° (95% CI 41°-46°), and mean pre- to post-surgical difference of - 19° (- 22 to - 16, I² = 96%), followed by the LCEA with a pooled mean post-operative angle of 30° (95% CI 29-31) and mean difference after surgery of - 4° (- 6 to - 1, I² = 97%,). Eleven studies reported on the correlation between radiographic and clinical outcomes with no consistent consensus correlation found amongst the included studies. Similarly, six studies correlated radiographic outcomes with conversion to THA with no consistent consensus correlation found amongst the included studies.

CONCLUSION

Based on this review, the main conclusion is that there is no consensus definition on the optimal radiographic correction for FAI and there was no consistent correlation between radiographic correction and functional outcomes. However, based on the uniform improvement in functional outcomes, this review suggests a post-operative alpha angle target of 44° with a correction target of 19° and LCEA target of 30° with a correction target of 3°.

LEVEL OF EVIDENCE

IV.

Medium-term results of arthroscopic treatment for femoroacetabular impingement

INTRODUCTION

Femoroacetabular impingement (FAI) is a dynamic pathomechanical process of the femoral head-neck junction. Arthroscopic surgery for FAI has increased exponentially in the last decade, and this trend is expected to increase.

SOURCE OF DATA

Recent published literatures.

AREAS OF AGREEMENT

FAI promotes quick rehabilitation and low complication rates in the short-term follow-up.

AREAS OF CONTROVERSY

Despite the growing interest on arthroscopic surgery for FAI, current evidence regarding the medium- and long-term role of arthroscopy are unsatisfactory.

GROWING POINTS

Systematically summarize current evidences, analyse the quantitative available data and investigate the medium- and long-term outcomes of arthroscopic surgery for FAI.

AREAS TIMELY FOR DEVELOPING RESEARCH

Arthroscopic surgery achieves very satisfactory outcomes for patients with FAI at a mean follow-up of 4 years.

Evaluation of outcome reporting trends for femoroacetabular impingement syndrome- a systematic review

PURPOSE

The aim of this systematic review was to evaluate the trends in the literature regarding surgical treatment for femoroacetabular impingement syndrome (FAIS) and to present which patient-reported outcome-measures (PROMs) and surgical approaches are included.

METHODS

This systematic review was conducted with the PRISMA guidelines. The literature search was performed on PubMed and Embase, covering studies from 1999 to 2020. Inclusion criteria were clinical studies with surgical treatment for FAIS, the use of PROMs as evaluation tool and studies in English. Exclusion criteria were studies with patients < 18 years, cohorts with < 8 patients, studies with primarily purpose to evaluate other diagnoses than FAIS and studies with radiographs as only outcomes without using PROMs. Data extracted were author, year, surgical intervention, type of study, level of evidence, demographics of included patients, and PROMs.

RESULTS

The initial search yielded 2,559 studies, of which 196 were included. There was an increase of 2,043% in the number of studies from the first to the last five years (2004-2008)-(2016-2020). There were 135 (69%) retrospective, 55 (28%) prospective and 6 (3%) Randomized Controlled Trials. Level of evidence ranged from I-IV where Level III was most common (44%). More than half of the studies (58%) originated from USA. Arthroscopic surgery was the most common surgical treatment (85%). Mean follow-up was 27.0 months (± 17 SD), (range 1.5-120 months). Between 1-10 PROMs were included, and the modified Harris Hip Score (mHHS) was most commonly used (61%).

CONCLUSION

There has been a continuous increase in the number of published studies regarding FAIS with the majority evaluating arthroscopic surgery. The mHHS remains being the most commonly used PROM.

Increased range of motion but otherwise similar clinical outcome of arthroscopy over open osteoplasty for femoroacetabular impingement at midterm follow-up: A systematic review

BACKGROUND

A systematic review was conducted comparing patient reported outcomes measures (PROMs), functional scores, and the rate of complications between arthroscopic and open treatment for femoroacetabular impingement (FAI) at mid-term follow-up.

MATERIAL AND METHODS

This systematic review was performed according to the PRISMA guidelines. The literature search was performed in October 2020. All clinical trials treating FAI using open osteoplasty or arthroscopic surgery were considered for inclusion. Only articles reporting >12 months follow-up were included.

RESULTS

Data from 97 articles (9981 procedures) were collected. At a mean 19.2 months follow-up there was no difference between the two cohorts. At a mean follow-up of 38 months, the external rotation was increased in the arthroscopic group (P < 0.0001). The modified Harris Hip Score scored greater in favour of the open osteoplasty group (P = 0.04), as did the Hip Outcome Score - Activities of Daily Living subscale (P = 0.01). At a mean 45.1 months the arthroscopic group presented greater external rotation (P < 0.0001) and SF-12 Mental (P = 0.04). The modified Harris Hip Score was greater in favour of the open osteoplasty group (P = 0.03), as was the HOS-ADL (P = 0.01). Regarding complications, the arthroscopic group experienced lower rates of subsequent revisions (P < 0.0001).

CONCLUSION

Based on the significant reduction of revisions-rate and significant increase in range of motion, arthroscopy treatment for the management of FAI may be recommended.

Higher risk of cam regrowth in adolescents undergoing arthroscopic femoroacetabular impingement correction: a retrospective comparison of 33 adolescent and 74 adults

Background and purpose - The current literature does not clarify the predictors of cam regrowth and poor clinical outcome following hip arthroscopic femoroacetabular impingement (FAI) correction surgery. Therefore, we investigated the prevalence and risk factors of cam regrowth following arthroscopic FAI correction surgery in skeletally immature patients compared with skeletally mature patients.Patients and methods - 33 teenagers (36 hips as 4 underwent bilateral hip arthroscopies, average age 16.7 [SD 1.6] years, 21 boys [22 hips], 12 girls [14 hips]) undergoing arthroscopic FAI correction and 74 adult controls (74 hips, average age 41 [SD 12] years, 42 men [42 hips], 32 women [32 hips]) were retrospectively reviewed. Postoperative radiographs were obtained, and cam regrowth was evaluated. Clinical characteristics, radiographic findings, arthroscopic findings, and procedures between skeletally immature (SI) and mature (SM) patients were compared. Average follow-up period was 28 months in the SI group and 24 months in the SM group.Results - Preoperatively, 27 of 36 hips were SI, having either a Risser sign grade ≤ 4 of iliac apophysis or open physes of the proximal femur. Cam regrowth was present in 4 of 27 SI hips. The number of cam regrowth cases was significantly higher in SI patients than in SM patients (0/74 hips). 6 patients required revision hip arthroscopic surgeries (4 men: FAI recurrence due to cam regrowth; 2 women: capsulolabral adhesions). At the last follow-up, the mean modified Harris hip score and nonarthritic hip score were significantly improved postoperatively.Interpretation - 4 of 27 SI hips (95% CI 0.04-0.3) had bone regrowth after cam resection arthroscopically. Our case series showed a non-negligible risk of cam regrowth in SI patients, especially in male patients and patients aged approximately 15 years.

[Surgical hip dislocation : Current status in the treatment of femoral acetabular impingement]

INTRODUCTION

Surgical hip dislocation (SHD) in the therapy of femoral acetabular impingement (FAI) has been mostly replaced by minimally invasive techniques. Nevertheless, in the circumstances of complex FAI types and combined impingement located in inaccessible areas of the hip, SHD is an option to reach those deformities. The advantage of the complete overview of the hip joint enables the circumferential therapy of bony deformity, but at the expense of higher invasivity. In the literature there is still a lack of mid to long-term studies of SHD to determine the overall treatment outcome. Therefore, the aim of this study is to evaluate the treatment outcome, risks and complications of SHD in FAI therapy within a mid-term follow-up.

METHODS

A total of 43 patients (mean follow-up 54 months.) with combined ventral and dorsal impingement who undertook SHD were retrospectively reviewed. Outcome parameters were range of motion (ROM), the Harris hip score (HHS), the hip outcome score (HOS), the activity level, pain, complications, conversion to total hip arthroplasty (THA) and patient specific surveys. Additionally, radiographs and the influence of preoperative osteoarthrosis were evaluated.

RESULTS

We were able to demonstrate a significant increase of ROM, HHS (69 → 80 Pkt.; p < 0.05), hip function and a decrease in pain level. The return to sport rate was 81%, but in most cases the patients had to reduce the intensity or change to a low impact sport activity. Overall, 75% were satisfied with the treatment outcome. The alpha angle improved from 70 to 45° (p < 0.05). Patients with preoperatively advanced hip osteoarthrosis showed no decent improvement of hip function. Conversion to THA was necessary in 36% of cases. The complication rate was about 13%.

CONCLUSION

SHD is successful in the treatment of combined ventral and dorsal impingement within a mid-term follow-up. The improvement of hip function and the reduction of pain symptoms is possible. In case of a manifest arthrosis an indication for SHD is no longer reasonable.

Prevalence and Consistency in Surgical Outcome Reporting for Femoroacetabular Impingement Syndrome: A Scoping Review

PURPOSE

The purposes of this review were (1) to collate and synthesize research studies reporting any outcome measure on both open and arthroscopic surgical treatment of femoroacetabular impingement (FAI) syndrome and (2) to report the prevalence and consistency of outcomes across the included studies.

METHODS

A computer-assisted literature search of the MEDLINE, CINAHL (Cumulative Index to Nursing and Allied Health Literature), and Embase databases was conducted using keywords related to FAI syndrome and both open and arthroscopic surgical outcomes, resulting in 2,614 studies, with 163 studies involving 14,824 subjects meeting the inclusion criteria. Two authors independently reviewed study inclusion and data extraction with independent verification. The prevalence of reported outcomes was calculated and verified by separate authors.

RESULTS

Between 2004 and 2016, there has been a 2,600% increase in the publication of surgical outcome studies. Patients had a mean duration of symptoms of 27.7 ± 21.5 months before surgery. Arthroscopy was the surgical treatment used in 71% of studies. The mean final follow-up period after surgery was 32.2 ± 17.3 months. Follow-up time frames were reported in 78% of studies. Ten different patient-reported outcome measures were reported. The alpha angle was reported to be measured 42% less frequently as a surgical outcome than as a surgical indication. Surgical complications were addressed in only 53% of studies and failures in 69%. Labral pathology (91% of studies reporting) and chondral pathology (61%) were the primary coexisting pathologies reported. Clinical signs, as defined by the Warwick Agreement on FAI syndrome, were reported in fewer than 25% of studies.

CONCLUSIONS

Most FAI syndrome patients have longstanding pain and potential coexisting pathology. Patient-reported outcome measures and diagnostic imaging are the most frequently reported outcomes. Measures of hip strength and range of motion are under-reported. It is unclear whether the inconsistency in reporting is because of lack of measurement or lack of reporting of specific outcomes in these studies. Current surgical outcomes are limited to mid-term surgical follow-up time frames and inconsistent outcome reporting.

LEVEL OF EVIDENCE

Level IV, systematic review of Level I through IV studies.

Detection of femoroplasty on pre- and post-arthroscopic comparison radiographs following treatment of femoroacetabular impingement syndrome: multi-reader accuracy and agreement study

OBJECTIVE

To assess diagnostic accuracy and agreement among radiologists in detecting femoroplasty on pre- and post-arthroscopic comparison frog lateral and anteroposterior (AP) pelvic radiographs after treatment of femoroacetabular impingement (FAI) syndrome.

MATERIALS AND METHODS

In this retrospective, cross-sectional study, 86 patients underwent hip arthroscopy (52 with and 34 without femoroplasty) for treatment of FAI syndrome. Three radiologists blinded to clinical data and chronological order of the pre- and post-arthroscopic comparison radiographs independently examined AP pelvis and frog lateral radiographs to detect femoroplasty changes. Statistical analysis outputs included diagnostic accuracy parameters and inter- and intra-observer agreement.

RESULTS

Identification of femoroplasty in the frog lateral projection has mean sensitivity 70%, specificity 82%, inter-observer agreement κ 0.74-0.76 and intra-observer agreement κ 0.72-0.85. Using the AP pelvis projection to detect femoroplasty has mean sensitivity 32%, specificity 71%, inter-observer agreement κ 0.47-0.65, and intra-observer agreement κ, 0.56-0.84.

CONCLUSIONS

Radiologists are only moderately sensitive, though more specific, in femoroplasty detection in the frog lateral projection. The AP pelvis projection yields lower sensitivity and specificity. Both projections have moderate inter- and intra-observer agreement.

Functional Outcomes and Cam Recurrence After Arthroscopic Treatment of Femoroacetabular Impingement in Adolescents

PURPOSE

To compare the functional outcomes after arthroscopic treatment of femoroacetabular impingement (FAI) in adolescent patients and non-adolescent patients, and to report on the rate of cam recurrence within 2 years after femoral osteoplasty in a limited sample of the adolescent group.

METHODS

From 2010 to 2014, patients younger than 18 years with symptomatic FAI (alpha angle >50°) who underwent hip arthroscopy with minimum 2-year follow-up or reoperation were identified. A group of non-adolescent patients with identical inclusion criteria, except age of 18 years or older, was also identified for comparison. In addition, a separate group of adolescent patients with 2-year postoperative radiographs was reviewed for cam recurrence. Demographic data, operative data, and radiographic and clinical outcomes (modified Harris Hip Score [mHHS], Hip Outcome Score-Activities of Daily Living [HOS-ADL], Hip Outcome Score-Sport-Specific Subscale [HOS-SSS], and International Hip Outcome Tool 33 [iHOT-33] score) were collected.

RESULTS

We identified 34 adolescent patients (38 hips) with an average age of 16 years (range, 13-17 years). The mean clinical follow-up period was 36.1 ± 11.6 months (range, 24.1-71.7 months) and 29.6 ± 2.4 months (range, 27.9-31.3 months) without and with reoperation, respectively. A control group of 296 non-adolescent patients (306 hips), with a mean age of 31 years (range, 18-59 years), was identified as our non-adolescent group. The mean clinical follow-up period was 34.1 ± 11 months (range, 24.0-77.4 months) and 15.1 ± 9.1 months (range, 3.6-34.6 months) without and with reoperation, respectively. Significant improvement was noted in adolescents in the changes in outcome scores (mHHS, 22.2 [95% confidence interval (CI), 15.4-29.0]; HOS-ADL, 18.6 [95% CI, 11.9-25.2]; HOS-SSS, 33.5 [95% CI, 24.5-42.5]; and iHOT-33 score, 30.5 [95% CI, 21.8-39.2]; P < .001). Similar improvements were observed in non-adolescents (mHHS, 21.0 [95% CI, 19.0-23.0]; HOS-ADL, 16.6 [95% CI, 14.6-18.6]; HOS-SSS, 30.1 [95% CI, 26.6-33.6]; and iHOT-33 score, 34.9 [95% CI, 31.5-38.3]; P < .001). There was no evidence of a difference in follow-up survey scores between groups (P > .203). Revision surgery was required in 2 adolescent hips (5.3% [95% CI, 1.5%-17.3%]) and 19 non-adolescent hips (6.2% [95% CI, 4.0%-9.5%]). Minimum 2-year radiographs were available for review in 24 adolescent patients (30 hips). The alpha angle (mean ± standard deviation) was reduced from 55.4° ± 12.1° preoperatively to 38.7° ± 4.9° at 6 weeks postoperatively (mean difference, -16.4° [95% CI, -19.8° to -12.9°]; P < .001). At 2 years, the alpha angle remained at 39.2° ± 11.2°, which did not differ from 6-week measurements (mean difference, 0.5° [95% CI, -2.9° to 3.9°]; P = .784). There were no cases of cam recurrence (0% [95% CI, 0%-11.4%]).

CONCLUSIONS

Significant improvement in clinical outcomes can be anticipated after arthroscopic treatment of FAI in adolescents. From a limited sample of our adolescent population, the risk of cam recurrence appears low; however, further follow-up is needed to ensure this does not represent a biased sample of the initial population.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

Radiographic outcomes reporting after arthroscopic management of femoroaceabular impingement: a systematic review

Femoroacetabular impingement (FAI) is a condition increasingly being recognized as a cause of hip pain and disability. Hip arthroscopy is a common method used to treat this condition. The purpose of this review was to identify reported radiographic outcomes after arthroscopic surgery for FAI. Online databases (PubMed, EMBASE, and Medline) were screened for studies involving arthroscopic management of FAI. Full-text reviews of eligible studies were conducted. We identified 23 eligible studies involving 1348 patients from an initial screen of 1304 studies involved. There were 15 different radiographic parameters among the 23 studies. The most commonly reported radiographic outcomes included the alpha angle (69.6 %), center edge angle (34.7 %), and femoral offset ratio (17.4 %). This study highlights the significant variation in reported radiographic outcomes after arthroscopic FAI surgery.

Femoral cam deformity due to anterior capsular force: A theoretical model with MRI and cadaveric correlation

BACKGROUND

Cam deformity is associated with epiphyseal extension onto the anterosuperior femoral head-neck before physeal closure. A century ago, anatomists speculated that this femoral prominence acts as a pulley bar to withstand capsular compression in hip extension with pressure concentrated where the zona orbicularis (ZO) joins the iliofemoral ligament (IFL). An animal model has shown that growth plates deflect laterally and distally when exposed to forces perpendicular to growth. These observations raise the question of whether capsular pressure against the epiphysis can stimulate cam formation.

PURPOSE

The purposes are to measure: (1) the distance from the ZO/IFL confluence to the maximal epiphyseal extension (MEE) and cam apex; and (2) acetabular depth at this location, since less coverage increases capsular contact on the physis.

METHODS

MRI scans of 39 subjects (47 hips) were measured. Acetabular depth was compared between those with and without a cam deformity. Secondarily, anatomic findings were correlated on a cadaveric specimen.

RESULTS

The cam apex and MEE were adjacent to the ZO/IFL confluence in all subjects (mean, 6.3 mm). Controlling for sex, acetabular depth was less (12.5%, p = 0.012) in the group with cam deformity. Contact points were confirmed in the specimen.

CONCLUSIONS

The cam apex and MEE occur at the ZO/IFL confluence in the thickest region of the anterosuperior capsule and vary with acetabular depth. This supports a theoretical model postulating that capsular forces against an immature epiphysis may induce cam formation, particularly in individuals who repetitively tension the anterior capsule.

Arthroscopy Up to Date: Hip Femoroacetabular Impingement

PURPOSE

To provide a comprehensive review and summary of the research published in Arthroscopy: The Journal of Arthroscopic and Related Surgery and The American Journal of Sports Medicine (AJSM) related to hip arthroscopy for femoroacetabular impingement (FAI).

METHODS

A comprehensive review was conducted in duplicate of Arthroscopy and AJSM from February 2012 to February 2015 for all articles related to FAI, and a quality assessment was completed for all included studies. Clinical outcomes were dichotomized into short-term (<6 months) and midterm (<24 months) outcomes, and values were pooled when possible.

RESULTS

We identified 60 studies in Arthroscopy and 44 studies in AJSM, primarily from North America (78.8%), that predominantly assessed clinical outcomes after arthroscopic hip surgery (46.1%). Seventy-one percent of Arthroscopy studies and 20.5% of AJSM studies were Level IV evidence. The modified Harris Hip Score (mHHS) was used by 81.5% of included studies. Pooled weighted mean mHHS values after arthroscopic surgery for FAI showed improvements at the midterm from 60.5 points (range, 56.6 to 83.6 points) to 80.5 points (range, 72.1 to 98.0 points) out of a possible 100 points. Pooled weighted outcomes for labral repair showed mean mHHS improvements from 63.8 points (range, 62.5 to 69.0 points) preoperatively to 86.9 points (range, 85.5 to 89.9 points) up to 24 months postoperatively.

CONCLUSIONS

This comprehensive review of research published in Arthroscopy and AJSM over the past 3 years identified a number of key findings. Arthroscopic intervention results in improvements in functional outcomes at both the short-term and midterm for patients with symptomatic FAI in the absence of significant existing degenerative changes. Labral repair may result in improvements over labral debridement. The most commonly used outcome score was the mHHS for objective assessment of surgical success. There is a need for continued focus on improvement of methodologic quality and reporting of research pertaining to FAI.

LEVEL OF EVIDENCE

Level IV, systematic review of Level IV studies.

Revision Hip Arthroscopy Indications and Outcomes: A Systematic Review

PURPOSE

To identify the indications and outcomes in patients undergoing revision hip arthroscopy.

METHODS

The electronic databases Embase, Medline, HealthStar, and PubMed were searched from 1946 to July 19, 2014. Two blinded reviewers searched, screened, and evaluated the data quality of the studies using the Methodological Index for Non-Randomized Studies scale. Data were abstracted in duplicate. Agreement and descriptive statistics are presented.

RESULTS

Six studies were included (3 prospective case series and 3 retrospective chart reviews), with a total of 448 hips examined. The most common indications for revision hip arthroscopy included residual femoroacetabular impingement (FAI), labral tears, and chondral lesions. The mean interval between revision arthroscopy and the index procedure was 25.6 months. Overall, the modified Harris Hip Score improved by a mean of 33.6% (19.3 points) from the baseline score at 1-year follow-up. In 14.6% of patients, further surgical procedures were required, including re-revision hip arthroscopy (8.0%), total hip replacement (5.6%), and hip resurfacing (1.0%). Female patients more commonly underwent revision hip arthroscopy (59.7%).

CONCLUSIONS

The current evidence examined in this review supports revision hip arthroscopy as a successful intervention to improve functional outcomes (modified Harris Hip Score) and relieve pain in patients with residual symptoms after primary FAI surgery, although the outcomes are inferior when compared with a matched cohort of patients undergoing primary hip arthroscopy for FAI. The main indication for revision is a candidate who has symptoms due to residual cam- or pincer-type deformity that was either unaddressed or under-resected during the index operation. However, it is important to consider that the studies included in this review are of low-quality evidence. Surgeons should consider incorporating a minimum 2-year follow-up for individuals after index hip-preservation surgery because revisions tended to occur within this time frame.

LEVEL OF EVIDENCE

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

Prevalence of radiological femoroacetabular impingement in Japanese hip joints: detailed investigation with computed tomography

BACKGROUND

Femoroacetabular impingement (FAI) has been highlighted as a new etiology for osteoarthritis of the hip, and its prevalence has been reported in the past decade. In the present study, we performed a detailed investigation of the anatomical parameters related to FAI and calculated the prevalence of FAI-related findings in asymptomatic Japanese hip joints using computed tomography.

METHODS

We evaluated high-resolution reconstructed multislice computed tomography images in patients who had undergone computed tomography imaging in our institution for conditions unrelated to hip disorders. The examined parameters were as follows: center-edge (CE) angle; acetabular index; acetabular anteversion (five slices in the axial plane); and asphericity angle of the femoral head (AAFH) (six slices in multiple radial planes). The AAFH in the oblique axial slice through the center of the femoral neck is the so-called α-angle. We then examined the accurate prevalence of FAI-related findings in Japan.

RESULTS

We investigated a total of 103 hips. The mean age of the subjects was 59.4 years. The mean CE angle was 31.1° and the mean acetabular index was 7.0°. The mean acetabular anteversion was 20.3° at the level of the hip center, and decreased as the slice level neared the superior margin of the femoral head. The mean AAFH ranged from 40.6° to 49.2° in the radial planes. The AAFH was largest at 60° rotated slice from the oblique axial slice through the center of the femoral neck. The prevalence of FAI-related findings in these Japanese hip joints was assessed as follows. An AAFH of >50° in any slice was detected in 51.5 % of the hips, and acetabular anteversion was negative for all images in 16.5 % of the hips, meaning that a total of 56.3 % of the images met the criteria for radiological FAI.

CONCLUSIONS

With consideration of our results, we emphasize that "anatomical or radiological FAI" is not uncommon in Japanese hips. Therefore, the diagnosis of FAI should be performed with the clinical findings taken into account.

Revision Hip Arthroscopy: A Systematic Review of Diagnoses, Operative Findings, and Outcomes

PURPOSE

To determine indications for, operative findings of, and outcomes of revision hip arthroscopy.

METHODS

A systematic review was registered with PROSPERO and performed based on PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Therapeutic clinical outcome studies reporting the indications for, operative findings of, and outcomes of revision hip arthroscopy were eligible for inclusion. All study-, patient-, and hip-specific data were extracted and analyzed. The Modified Coleman Methodology Score was used to assess study quality.

RESULTS

Five studies were included (348 revision hip arthroscopies; 333 patients; mean age, 31.4 ± 4.2 years; 60% female patients). All 5 studies were either Level III or IV evidence. The surgeon performing revision hip arthroscopy was the same as the primary hip surgeon in only 25% of cases. The mean time between primary and revision hip arthroscopy was 27.8 ± 7.0 months (range, 2 to 193 months). Residual femoroacetabular impingement was the most common indication for and operative finding of revision hip arthroscopy (81% of cases). The most commonly reported revision procedures were femoral osteochondroplasty (24%) and acetabuloplasty (18%). The modified Harris Hip Score was used in all 5 analyzed studies, with significant (P < .05) improvements observed in all 5 studies (weighted mean, 56.8 ± 3.6 preoperatively v 72.0 ± 8.3 at final follow-up [22.4 ± 9.8 months]; P = .01). Other patient-reported outcomes (Non-Arthritic Hip Score, Hip Outcome Score, 33-item International Hip Outcome Tool, Short Form 12) showed significant improvements but were not used in all 5 analyzed studies. After revision hip arthroscopy, subsequent reported operations were hip arthroplasty in 11 patients and re-revision hip arthroscopy in 8 patients (5% total reoperation rate).

CONCLUSIONS

Revision hip arthroscopy is most commonly performed for residual femoroacetabular impingement, with statistically significant and clinically relevant improvements shown in multiple patient-reported clinical outcome scores at short-term follow-up. The reoperation rate after revision hip arthroscopy is 5% within 2 years, including further arthroscopy or conversion to hip arthroplasty.

LEVEL OF EVIDENCE

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

High affinity recognition of a Phytophthora protein by Arabidopsis via an RGD motif

The RGD tripeptide sequence, a cell adhesion motif present in several extracellular matrix proteins of mammalians, is involved in numerous plant processes. In plant-pathogen interactions, the RGD motif is believed to reduce plant defence responses by disrupting adhesions between the cell wall and plasma membrane. Photoaffinity cross-linking of [125I]-azido-RGD heptapeptide in the presence of purified plasma membrane vesicles of Arabidopsis thaliana led to label incorporation into a single protein with an apparent molecular mass of 80 kDa. Incorporation could be prevented by excess RGD peptides, but also by the IPI-O protein, an RGD-containing protein secreted by the oomycete plant pathogen Phytophthora infestans. Hydrophobic cluster analysis revealed that the RGD motif of IPI-O (positions 53-56) is readily accessible for interactions. Single amino acid mutations in the RGD motif in IPI-O (of Asp56 into Glu or Ala) resulted in the loss of protection of the 80-kDa protein from labelling. Thus, the interaction between the two proteins is mediated through RGD recognition and the 80-kDa RGD-binding protein has the characteristics of a receptor for IPI-O. The IPI-O protein also disrupted cell wall-plasma membrane adhesions in plasmolysed A. thaliana cells, whereas IPI-O proteins mutated in the RGD motif (D56A and D56E) did not.