Christopher M Larson

Minnesota Orthopedic Sports Medicine Institute at Twin Cities Orthopedics, Edina, Minnesota, United States

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Publications (73)198.83 Total impact

  • James R Ross · Rebecca M Stone · Christopher M Larson ·
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    ABSTRACT: Core muscle injury/sports hernia/athletic pubalgia is an increasingly recognized source of pain, disability, and time lost from athletics. Groin pain among athletes, however, may be secondary to various etiologies. A thorough history and comprehensive physical examination, coupled with appropriate diagnostic imaging, may improve the diagnostic accuracy for patients who present with core muscular injuries. Outcomes of nonoperative management have not been well delineated, and multiple operative procedures have been discussed with varying return-to-athletic activity rates. In this review, we outline the clinical entity and treatment of core muscle injury and athletic pubalgia. In addition, we describe the relationship between athletic pubalgia and femoroacetabular impingement along with recent studies that have investigated the treatment of these related disorders.
    Sports medicine and arthroscopy review 11/2015; 23(4):213-220. DOI:10.1097/JSA.0000000000000083 · 1.68 Impact Factor
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    ABSTRACT: Purpose: The purpose of this study was to describe the occurrence of ischiofemoral impingement (IFI) and hamstring dysfunction following malunion or non-union of ischial tuberosity apophyseal avulsion fractures and report the short-term outcomes of surgical treatment with regard to alleviating symptomatic extra-articular impingement. Methods: All patients who underwent surgery for recalcitrant hip and buttock pain in the setting of prior ischial tuberosity avulsion fracture at three tertiary-level hip preservation centres were included for this review. A total of ten patients met our inclusion criteria and underwent sciatic neurolysis, resection of the ischial tuberosity fragment and hamstring reattachment. Clinical outcomes scores were collected post-operatively including the Modified Harris Hip Score (mHHS) and the Hip Outcomes Score (HOS). Results: Ten patients with a mean age of 18 years (range 14-28) underwent surgery for symptomatic ischiofemoral impingement after ischial tuberosity avulsion fracture. At a mean of 2.2-year follow-up (range 1.7-3.5), the median post-operative mHHS was 89.7 (65.7-96.8) and HOS ADL and Sport subscales were 90 % or greater in all cases. Five patients (50 %) rated their hip as normal, and five patients (50 %) rated their hip as near normal. Conclusion: Malunion or non-union following ischial tuberosity apophyseal fracture can lead to IFI and hamstring dysfunction. Clinically, the resultant pain and dysfunction is often chronic, and can be debilitating. In select cases, a reliable surgical technique is presented to improve hamstring function and correct ischiofemoral impingement in this setting with good-to-excellent outcomes in the majority of cases at short-term follow-up. Level of evidence: IV.
    Knee Surgery Sports Traumatology Arthroscopy 10/2015; DOI:10.1007/s00167-015-3812-4 · 3.05 Impact Factor
  • James R. Ross · Asheesh Bedi · John C. Clohisy · Joel J. Gagnier · Christopher M. Larson ·

    Arthroscopy The Journal of Arthroscopic and Related Surgery 09/2015; DOI:10.1016/j.arthro.2015.07.003 · 3.21 Impact Factor
  • E. A. Crawford · K. L. Welton · C. Kweon · B. T. Kelly · C. M. Larson · A. Bedi ·

    08/2015; 3(8):e4-e4. DOI:10.2106/JBJS.RVW.N.00096
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    ABSTRACT: To present outcomes in a series of patients with Ehlers-Danlos syndrome (EDS)-hypermobility type who underwent hip arthroscopy for associated hip pain and extreme capsular laxity. A retrospective chart review identified 16 hips with confirmed EDS-hypermobility type that underwent hip arthroscopy for continued pain and capsular laxity. All patients had complaints of "giving way" and pain, an easily distractible hip with manual traction under fluoroscopy, and a patulous capsule at the time of surgery. No patient had osseous evidence of acetabular hip dysplasia or prior confirmed hip dislocation. Outcomes were evaluated preoperatively and postoperatively with the modified Harris Hip Score (mHHS), the 12-Item Short Form Health Survey (SF-12), and a visual analog scale (VAS) for pain. Evidence of symptomatic femoroacetabular impingement (FAI) was found in 15 hips (93.8%). The 16th hip had subjective giving way with a positive anterior impingement test and was easily distractible, had a labral tear, and had a patulous capsule at the time of surgery. The mean follow-up period was 44.61 months (range, 12 to 99 months). The mean preoperative lateral center-edge angle was 31.8° (range, 25° to 44°), and the mean Tönnis angle was 3.6° (range, -2° to 8°). Mean femoral version measured on computed tomography (CT) scans was 19.2° (range, -4.0° to 31.0°). Of the hips, 13 underwent primary arthroscopy and 3 underwent revision. All hips underwent hip arthroscopy with an interportal capsular cut only and arthroscopic capsular plication. There were 13 labral repairs, 2 labral debridements, 8 rim resections, 15 femoral resections, 2 psoas tenotomies, and 1 microfracture. Improved stability with an inability to distract the hip with manual traction under fluoroscopy was noted in all hips after plication. The mean alpha angle preoperatively was 58.7° on anteroposterior radiographs and 63.6° on lateral radiographs compared with 47.4° and 46.1°, respectively, postoperatively. There were significant improvements for all outcomes (mHHS, P = .002; SF-12 score, P = .027; and VAS score, P = .0004). The mean mHHS, SF-12 score, and VAS score were 45.6 points, 62.4 points, and 6.5 points, respectively, preoperatively compared with 88.5 points, 79.3 points, and 1.6 points, respectively, at a mean follow-up of 45 months. No EDS patients were lost to follow-up or excluded from analysis. The mean improvement in mHHS from preoperatively to postoperatively was 42.9 points, and there were no iatrogenic dislocations. One patient underwent further revision arthroscopy for recurrent pain, subjective giving way, and capsular laxity. FAI and extreme capsular laxity can be seen in the setting of EDS. Although increased femoral version was common, acetabular dysplasia was not common in our study. Meticulous capsular plication, arthroscopic correction of FAI when present, and labral preservation led to dramatic improvements in outcomes and subjective stability without any iatrogenic dislocations in this potentially challenging patient population. Level IV, therapeutic case series. Copyright © 2015 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.
    Arthroscopy The Journal of Arthroscopic and Related Surgery 07/2015; DOI:10.1016/j.arthro.2015.06.005 · 3.21 Impact Factor
  • James R. Ross · Rebecca M. Stone · Christopher M. Larson ·
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    ABSTRACT: Femoroacetabular impingement is typically described as occurring between the femoral head-neck junction and the acetabular rim and secondary to pathomorphologic osseous changes in these areas. Extra-articular sources of femoroacetabular impingement have been increasingly recognized and treated. One of the more commonly described sources has been subspine impingement, the mechanical conflict between the anterior inferior iliac spine (AIIS) and the distal femoral neck. The etiologies of AIIS pathomorphology include apophyseal avulsions of the AIIS, rectus femoris avulusions with ossification, overcorrection after periacetabular osteotomy, and developmental. Patients often present with groin pain with deep hip flexion. Cadaveric studies have noted a reproducible bare area on the inferior aspect of the AIIS, and a corresponding footprint of the direct head of the rectus femoris measuring 2.2 × 1.6 cm on average. Arthroscopic decompression of the AIIS has been performed with good short-term outcomes and significant improvement in end terminal range of motion.
    Operative Techniques in Sports Medicine 07/2015; 23(3). DOI:10.1053/j.otsm.2015.06.004 · 0.20 Impact Factor
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    Christopher Larson · James Ross · M. Russell Giveans · Rebecca Stone · Emma Grossi · Asheesh Bedi ·

    Arthroscopy The Journal of Arthroscopic and Related Surgery 06/2015; 31(6):e16-e17. DOI:10.1016/j.arthro.2015.04.045 · 3.21 Impact Factor
  • Ryan A. Mlynarek · James B. Cowan · Christopher M. Larson · Bryan T. Kelly · Asheesh Bedi ·
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    ABSTRACT: Femoroacetabular impingement (FAI) is a common, debilitating cause of hip pain for many individuals. Recent literature suggests that for a significant proportion of these patients, FAI is a precursor for early degenerative disease of the hip. Advances in our understanding of the disease, imaging technology and surgical techniques has enabled surgeons to address this structural disease. Hip preservation surgery has continued to grow in popularity over the past decade. In fact, there has been an 18-fold increase in the number of hip arthroscopy procedures performed by American Board of Orthopaedic Surgery candidates from 2003 to 2009. More importantly, many studies have reported good to excellent short- and mid-term outcomes. Furthermore, hip arthroscopy has been shown to be a cost-effective mode of treatment among patients with FAI without arthritis. Arthroscopy is a preferred approach to amenable pathological deformities and can be associated with fewer complications than other operative techniques.
    The Journal of arthroplasty 04/2015; 30(7). DOI:10.1016/j.arth.2015.04.016 · 2.67 Impact Factor
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    ABSTRACT: Objectives: Previous reports regarding arthroscopic management of dysplastic hip morphologies have conflicting results. Arthroscopy alone in the setting of dysplastic morphologies is controversial.
    03/2015; 3(1 Suppl). DOI:10.1177/2325967115S00022
  • Asheesh Bedi · James R Ross · Bryan T Kelly · Christopher M Larson ·
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    ABSTRACT: Complications and failures after hip arthroscopy are reported to be relatively uncommon. Because there are no recent comprehensive, prospective studies observing complications and failures after hip arthroscopy, the current rates are unclear. As the number of surgeons performing hip arthroscopy and the number of procedures performed continue to increase, there is the need for an increased awareness of potential adverse events.
    Instructional course lectures 03/2015; 64:297-306.
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    ABSTRACT: This systematic review assessed the role of hip arthroscopic irrigation and debridement for eradication of infection in native joints to ascertain outcomes and complications associated with this surgical approach. The Medline, Embase, and PubMed databases were searched on July 20, 2014, for English-language studies that addressed arthroscopic treatment of native septic hip arthritis. The studies were systematically screened and data abstracted in duplicate, with qualitative findings presented. There were 11 eligible studies (1 case-control study, 8 case series, and 2 case reports) reporting on 65 patients (65 hips) treated by arthroscopic irrigation and debridement for septic hip arthritis. The mean length of patient follow-up was 19.1 months (range, 6 to 84 months). The indications for surgery were as follows: pyrexia, anterior groin or hip pain with limited hip range of motion and an inability to bear weight, associated leukocytosis, an elevated erythrocyte sedimentation rate or C-reactive protein level, and/or hip imaging or aspiration results consistent with infection. Specific contraindications for surgery reported across studies included tuberculous of fungal infection, coexistence of osteomyelitis, immunocompromised individuals, and pre-existing surgery on the affected hip. The initial rate of infection eradication was 100%. All studies reported significant improvements in patient pain and function. Improvements were also observed in range of motion, as well as across both the Bennett radiographic and clinical assessments and Harris Hip Score. No complications, major or minor, were reported, and only 1 of 65 hips (1.5%) required revision arthroscopy for recurrence because of a methicillin-resistant Staphylococcus aureus infection. Arthroscopic native hip irrigation and debridement for septic arthritis appear to comprise a safe and effective treatment option for selected patients (e.g., no deformity, no bacterial infections, and not immunocompromised). Timely diagnosis and intervention, however, remain the most critical prognostic factors for successful outcomes. Level IV, systematic review of Level IV and V studies. Copyright © 2015 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.
    Arthroscopy The Journal of Arthroscopic and Related Surgery 02/2015; 31(7). DOI:10.1016/j.arthro.2014.12.028 · 3.21 Impact Factor

  • Arthroscopy The Journal of Arthroscopic and Related Surgery 02/2015; · 3.21 Impact Factor
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    ABSTRACT: Background Often, anteroposterior (AP) pelvic radiographs are performed with the patient positioned supine. However, this may not represent the functional position of the pelvis and the acetabulum, and so when assessing patients for conditions like femoroacetabular impingement (FAI), it is possible that standing radiographs better incorporate the dynamic influences of periarticular musculature and sagittal balance. However, this thesis remains largely untested. Questions/purposes The purpose of this study was to determine the effect of supine and standing pelvic orientation on (1) measurements of acetabular version and common radiographic signs of FAI as assessed on two- and three-dimensional (3-D) imaging; and (2) on terminal hip range of motion (ROM). Methods Preoperative pelvic CT scans of 50 patients (50 hips) who underwent arthroscopic surgery for the treatment of FAI between July 2013 and October 2014 were analyzed. The mean age of the study population was 29 ± 10 years (range, 15–50 years) and 70% were male. All patients had a standing AP pelvis radiograph, a reconstructed supine radiograph from the CT data, and a 3-D model created to allow manipulation of pelvic tilt and simulate ROM to osseous contact. Acetabular version was measured and the presence of the crossover sign, prominent ischial spine sign, and posterior wall sign were recorded on simulated plain radiographs. Measurements of ROM to bony impingement were made during (1) simulated hip flexion; (2) simulated internal rotation in 90° of flexion (IRF); and (3) simulated internal rotation in 90° of flexion and 15° adduction (FADIR), and the location of bony contact between the proximal femur and acetabular rim was defined. These measurements were calculated for supine and standing pelvic orientations. A paired Student’s t-test was used for comparison of continuous variables, whereas chi square testing was used for categorical variables. A p value of
    Clinical Orthopaedics and Related Research 01/2015; 473(4). DOI:10.1007/s11999-014-4104-x · 2.77 Impact Factor
  • S.J. Nho · M. Leunig · C.M. Larson · A. Bedi · B.T. Kelly ·
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    ABSTRACT: Hip pathology and nonarthritic hip conditions have only recently been recognized as a cause of hip pain. In 2003, Ganz, Leunig and colleagues described the concept of femoroacetabular impingement (FAI) as a cause of hip pain and a mechanism for end-stage hip osteoarthritis. Ganz et al. also postulated that 70-90% of hip osteoarthritis is likely due to abnormal hip mechanics related to FAI, dysplasia, or other hip deformities. Over the past ten years, the treatment of these non-arthritic hip pathologies has grown dramatically, and has been estimated to grow by 15% each year. It is the largest segment of grown in sports medicine and orthopedics as a whole. However, no definitive reference yet exists on hip arthroscopy and hip joint preservation surgery. While books have been published on hip arthroscopy, these texts are limited to the technical aspects of the procedure and do not explore content related to hip joint preservation surgery. The scope of this book covers the basic science of hip pathology, anatomy, biomechanics, pathology, and treatment. It has put together up-to-date research and has invited opinion leaders in the field to contribute to the text. The book is focused on disease pathology and provides comprehensive information on each disease topic, which is followed by technique-driven chapters to provide surgeons a reference for any procedure related to non-arthritic conditions of the hip.
  • Christopher M. Larson · Geoffrey D. Cornelsen · Rebecca M. Stone ·
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    ABSTRACT: Proximal hamstring avulsion injuries are more commonly being recognized and can cause significant disability for the active patient. Patients frequently experience a loss of leg control and difficulties decelerating the leg, making athletic activities difficult. Unfortunately, patients may present late due to either misdiagnosis or failed attempts at conservative treatment. Retraction and scarring of the hamstring tendons can limit the surgeon’s ability to repair the tendon to the ischial tuberosity without excessive tension. Use of an Achilles tendon allograft, can obviate the need for distal fractional lengthening or tenodesis and provides improved outcomes for activities of daily living and sports-related activities. This chapter provides key history and exam findings to aid in diagnosis and describes the surgical procedure for allograft reconstruction for irreparable ruptures. Tendon fixation is described through use of either suture anchors or bone plug and interference screw depending on patient characteristics and intraoperative visualization. Postoperative protocols including hinged knee bracing are outlined. Most patients return to sport by 6 months although will improve for a year following the surgery. Posterior thigh numbness and superficial skin infection are the most common adverse events. Return to sports is inferior to acute repair, but return to activities of daily living is comparable to acute repairs with universally high satisfaction rates after allograft reconstruction.
  • Asheesh Bedi · Acker, W.B., II · James R. Ross · Christopher M. Larson ·
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    ABSTRACT: The use of hip arthroscopy has rapidly increased over the past 30 years and investigations into its use have seen an exponential increase over the past decade. Advancements in techniques and instrumentation have allowed an increasing number of orthopedists to perform this operation to address a rapidly expanding number of disorders of the hip and adjacent anatomy. Hip arthroscopy is most commonly performed for intra-articular conditions such as FAI, labral and chondral lesions, disorders of the synovium and capsule, loose bodies, ligamentum teres injuries, and septic arthritis and as a diagnostic aid in conjunction with other procedures. Periarticular conditions such as greater trochanteric pain syndrome, snapping hip, extra-articular FAI, and pathology in the posterior gluteal space are also increasingly addressed with the aid of hip arthroscopy. Contraindications to the procedure, as its strengths and limitations are better defined through increased study and use, have also evolved. These include the presence of advance stages of osteoarthritis, inflammatory arthritis, various forms of hip dysplasia, chronic muscle pathology, preexisting neurologic injury, and greater trochanter impingement, among others. This chapter will expand upon these indications and contraindications, reviewing evidence to help guide both beginner and advanced hip arthroscopists. As the use of hip arthroscopy continues to expand, the utility and limitations of its use will continue to evolve.
  • Joshua D. Harris · Christopher M. Larson · Shane J. Nho ·
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    ABSTRACT: Recognition of femoroacetabular impingement as a potential precursor to hip osteoarthritis has led to the development of both open and arthroscopic hip preservation surgery. Successful short- and midterm clinical outcomes have been reported following hip preservation surgery. Improvements in technique and instrumentation have led to a dramatic increase in the number of surgeons performing hip arthroscopy and the number of cases performed internationally.However, there is a significant learning curve associated with hip arthroscopy. Although the rate of minor complications is low (7.5 %), it is largely related to the learning curve. The two most common minor complications are iatrogenic chondrolabral injury and temporary neuropraxia. Open surgical hip dislocation permits a 360 A view of the femoral head and acetabulum but requires a larger incision, greater soft tissue dissection, and a trochanteric osteotomy. Although the rate of minor complications is reportedly higher following open surgical hip dislocation due to the occasional development of painful hardware requiring removal, the rate of major complications is less than 1 % in both open and arthroscopic hip preservation surgery. Thus, both open and arthroscopic hip preservation surgeries appear to be safe. Lack of clarity in reporting complications within orthopedic surgery has spurred academic hip surgeons to adapt and test a general surgery-validated complication reporting system for use in hip preservation.
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    ABSTRACT: This study aimed to characterize the radiographic deformity observed in a consecutive series of butterfly goalies with symptomatic mechanical hip pain and to use computer-based software analysis to identify the location of impingement and terminal range of motion. We also compared these analyses to a matched group of positional hockey players with symptomatic femoroacetabular impingement (FAI). A consecutive series of 68 hips in 44 butterfly-style hockey goalies and a matched group of 34 hips in 26 positional hockey players who underwent arthroscopic correction for symptomatic FAI were retrospectively analyzed. Each patient underwent preoperative anteroposterior (AP) and modified Dunn lateral radiographs and computed tomography (CT) of the affected hips. Common FAI measurements were assessed on plain radiographs. Patient-specific, CT-based 3-dimensional (3D) models of the hip joint were developed, and the femoral version, alpha angles at each radial clock face position, and femoral head coverage were calculated. Maximum hip flexion, abduction, internal rotation in 90° flexion (IRF), flexion/adduction/internal rotation (FADIR), and butterfly position were determined, and the areas of bony collision were defined. Butterfly goalies had an elevated mean alpha angle on both AP (61.3°) and lateral radiographs (63.4°) and a diminished beta angle (26.0°). The mean lateral center-edge angle (LCEA) measured 27.3° and acetabular inclination was 6.1°. A crossover sign was present in 59% of the hips. The maximum alpha angle on the radial reformatted computed tomographic scan was significantly higher among the butterfly goalies (80.9° v 68.6°; P < .0001) and was located in a more lateral position (1:00 o'clock v. 1:45 o'clock; P < .0001) compared with positional players. Symptomatic butterfly hockey goalies have a high prevalence of FAI, characterized by a unique femoral cam-type deformity and noted by an elevated alpha angle and loss of offset, which is greater in magnitude and more lateral when compared with that in positional hockey players. Associated acetabular dysplasia is also common among hockey goalies. Level IV, prognostic case series. Copyright © 2015 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.
    Arthroscopy The Journal of Arthroscopic and Related Surgery 12/2014; 31(4). DOI:10.1016/j.arthro.2014.10.010 · 3.21 Impact Factor
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    James R Ross · Christopher M Larson · Olusanjo Adeoyo · Bryan T Kelly · Asheesh Bedi ·
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    ABSTRACT: Previous studies have reported residual deformity to be the most common reason for revision hip arthroscopy. An awareness of the most frequent locations of the residual deformities may be critical to minimize these failures. The purposes of this study were to (1) define the three-dimensional (3-D) morphology of hips with residual symptoms before revision femoroacetabular impingement (FAI) surgery; (2) determine the limitation in range of motion (ROM) in these patients using dynamic, computer-assisted, 3-D analysis; and (3) compare these measures with a cohort of patients who underwent successful arthroscopic surgery for FAI by a high-volume hip arthroscopist. Between 2008 and 2013, one senior surgeon (BTK) performed revision arthroscopic FAI procedures on patients with residual FAI deformity and symptoms after prior unsuccessful arthroscopic surgery; all of these 47 patients (50 hips) had preoperative CT scans. Mean patient age was 29 ± 9 years (range, 16-52 years). Three-dimensional models of the hips were created to allow measurements of femoral and acetabular morphology and ROM to bony impingement using a validated, computer-based dynamic imaging software. During the same time period, 65 patients with successful primary arthroscopic treatment of FAI by the same surgeon underwent preoperative CT scans for the symptomatic contralateral hip; this group of 65 patients thus fortuitously provided postoperative evaluation of the originally operated hip and served as a control group. A comparison of the virtual correction with the actual correction in the primary successful FAI treatment cohort was performed. Correspondingly, a comparison of the recommended virtual correction with the correction evident at the time of presentation after failed primary surgery in the revision cohort was performed. Analysis was performed by two independent observers (JRR, OA) and a paired t-test was used for comparison of continuous variables, whereas chi-square testing was used for categorical variables with p < 0.05 defined as significant. Ninety percent (45 of 50) of patients undergoing revision surgery for symptomatic FAI had residual deformities; the mean maximal alpha angle in revision hips was 68° ± 16° and was most often located at 1:15, considering the acetabulum as a clockface and 1 to 5 o'clock as anterior independent of side. Twenty-six percent (13 of 50) of hips had signs of overcoverage with a lateral center-edge angle greater than or equal to 40°. Dynamic analysis revealed mean direct hip flexion of 114° ± 11° to osseous impingement. Internal rotation in 90° of hip flexion and flexion, adduction, internal rotation to osseous contact were 28° ± 12° and 20° ± 10°, respectively, which were less than those in hips that had underwent hip arthroscopy by a high-volume hip arthroscopist (all p < 0.001). We found marked radiographic evidence of incomplete correction of deformity in patients with residual symptoms compared with patients with successful results with residual deformity present in the large majority of patients (45 of 50 [90%]) undergoing residual FAI surgery. We recommend careful attention to full 3-D resection of impinging structures. Level III, retrospective study, case series.
    Clinical Orthopaedics and Related Research 12/2014; 473(3). DOI:10.1007/s11999-014-4069-9 · 2.77 Impact Factor
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    ABSTRACT: Plain radiographic measures of the acetabulum may fail to accurately define coverage or pathomorphology such as impingement or dysplasia. CT scans might provide more precise measurements for overcoverage and undercoverage. However, a well-defined method for such CT-based measurements and normative data regarding CT-based acetabular coverage is lacking. The purposes of the study were (1) to develop a method for evaluation of percent coverage of the femoral head by the acetabulum; and (2) to define normative data using a cohort of asymptomatic patient hip and pelvic CT scans and evaluate the variability in acetabular version for asymptomatic patients with normal lateral coverage (lateral center-edge angle [LCEA] 20°-40°) that has previously been defined as abnormal based on radiographic parameters. Two-hundred thirty-seven patients (474 hips) with hip CT scans obtained for reasons other than hip-related pain were evaluated. The scans were obtained from a hospital database of patients who underwent CT evaluation of abdominal trauma or pain. In addition, hips with obvious dysplasia (LCEA < 20°) or profunda (LCE > 40°) were excluded resulting in a final cohort of 222 patients (409 hips [115 men, 107 women]) with CT scans and a mean age of 25 ± 3 years. CT scan alignment was corrected along the horizontal and vertical axis and percent acetabular coverage around the clockface (3 o'clock = anterior), and regional (anterior, superior, posterior) and global surface area coverage was determined. Percent coverage laterally was correlated with the LCEA and the presence and prevalence of cranial retroversion (crossover sign) and a positive posterior wall sign were determined. The mean regional percent femoral head surface area coverage for the asymptomatic cohort was 40% ± 2% anteriorly, 61% ± 3% superiorly, and 48% ± 3% posteriorly. Mean global coverage of the femoral head was 40% ± 2%. The local coverage anteriorly (3 o'clock) was 38% ± 3%, laterally (12 o'clock) was 67% ± 2%, and posteriorly (9 o'clock) was 52% ± 3%. The mean lateral coverage represented a mean LCEA of 31° (± 1 SD). Fifteen percent of hips demonstrated cranial retroversion that would correlate with a crossover sign, and 30% had < 50% posterior coverage that would correlate with a positive posterior wall sign on an anteroposterior pelvis radiograph. In addition, male hips had a higher prevalence of a crossover sign (19%; 95% confidence interval [CI], 14%-25% versus 11%; 95% CI, 7%-16%; p = 0.03) and posterior wall sign (46%; 95% CI. 39%-53% versus 13%; 95% CI, 9%-19%; p < 0.001) compared with women. A positive crossover sign or posterior wall sign was present for 113 male hips (53%; 95% CI, 46%-60%) compared with 39 female hips (20%; 95% CI, 15%-26%; p < 0.001). This study provides normative coverage data and a reproducible method for evaluating acetabular coverage. Cranial acetabular retroversion (crossover sign) and a positive posterior wall sign were frequent findings in a young asymptomatic cohort and might be a normal variant rather than pathologic in a significant number of cases. Level III, diagnostic study.
    Clinical Orthopaedics and Related Research 11/2014; 473(4). DOI:10.1007/s11999-014-4055-2 · 2.77 Impact Factor

Publication Stats

1k Citations
198.83 Total Impact Points


  • 2009-2015
    • Minnesota Orthopedic Sports Medicine Institute at Twin Cities Orthopedics
      Edina, Minnesota, United States
  • 2014
    • University of Grenoble
      Grenoble, Rhône-Alpes, France
    • University of Michigan
      Ann Arbor, Michigan, United States
    • University of Missouri - St. Louis
      Сент-Луис, Michigan, United States
  • 2012-2013
    • Washington University in St. Louis
      • Department of Orthopaedic Surgery
      San Luis, Missouri, United States
    • Hospital for Special Surgery
      • Department of Orthopaedic Surgery
      New York City, New York, United States