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James S. Keene - One of the best experts on this subject based on the ideXlab platform.
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MR Appearance and Clinical Significance of Changes in the Hip Muscles and Iliopsoas Tendon After Arthroscopic Iliopsoas Tenotomy in Symptomatic Patients
HSS Journal ®, 2013Co-Authors: Kendra S. Hain, Donna G. Blankenbaker, Arthur A. Smet, James S. Keene, Alejandro Munoz RioAbstract:Background Iliopsoas tenotomy is a treatment for snapping hip. Does this surgical procedure change the surrounding muscle and tendon anatomy? Questions/Purposes This study seeks to evaluate the changes in the MR appearance of the hip muscles and Iliopsoas tendon in patients following arthroscopic Iliopsoas tenotomy. Methods One hundred sixty-nine consecutive adults were evaluated after Iliopsoas tenotomy at the lesser trochanter. Each MR exam was evaluated independently by three radiologists for muscle edema, atrophy (grade 0–4), compensatory hypertrophy, signal within the Iliopsoas tendon (increased on T1 or T2 sequences), and Iliopsoas tendon morphology (distorted or disrupted) above, at, and below the iliopectineal eminence. A finding was considered positive if reported by two or three of the radiologists. Results Twenty subjects met the inclusion criteria. Muscle edema was present in 15% (3/20) of subjects within the iliacus, psoas, and quadratus femoris. Atrophy was observed in the following muscles: iliacus 85% (17/20), psoas 75% (15/20), quadratus femoris 10% (2/20), rectus femoris 5% (1/20), vastus lateralis 5% (1/20), and gluteus maximus 25% (5/20). There was no compensatory hypertrophy. Ninety percent (18/20) had increased T1 and 10% (2/20) had increased T2 signal within the Iliopsoas tendon. Thirty-five percent (7/20) of the Iliopsoas tendons was disrupted and 85% (17/20) was distorted, most commonly below the iliopectineal eminence. Conclusion The majority of postoperative symptomatic patients has atrophy of the iliacus and psoas muscles and distortion and disruption of the Iliopsoas tendon and should be recognized as a normal imaging appearance following Iliopsoas tendon release.
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MR Appearance and Clinical Significance of Changes in the Hip Muscles and Iliopsoas Tendon After Arthroscopic Iliopsoas Tenotomy in Symptomatic Patients
HSS journal : the musculoskeletal journal of Hospital for Special Surgery, 2013Co-Authors: Kendra S. Hain, Donna G. Blankenbaker, Arthur A. Smet, James S. Keene, Alejandro Munoz Del RioAbstract:Iliopsoas tenotomy is a treatment for snapping hip. Does this surgical procedure change the surrounding muscle and tendon anatomy? This study seeks to evaluate the changes in the MR appearance of the hip muscles and Iliopsoas tendon in patients following arthroscopic Iliopsoas tenotomy. One hundred sixty-nine consecutive adults were evaluated after Iliopsoas tenotomy at the lesser trochanter. Each MR exam was evaluated independently by three radiologists for muscle edema, atrophy (grade 0-4), compensatory hypertrophy, signal within the Iliopsoas tendon (increased on T1 or T2 sequences), and Iliopsoas tendon morphology (distorted or disrupted) above, at, and below the iliopectineal eminence. A finding was considered positive if reported by two or three of the radiologists. Twenty subjects met the inclusion criteria. Muscle edema was present in 15% (3/20) of subjects within the iliacus, psoas, and quadratus femoris. Atrophy was observed in the following muscles: iliacus 85% (17/20), psoas 75% (15/20), quadratus femoris 10% (2/20), rectus femoris 5% (1/20), vastus lateralis 5% (1/20), and gluteus maximus 25% (5/20). There was no compensatory hypertrophy. Ninety percent (18/20) had increased T1 and 10% (2/20) had increased T2 signal within the Iliopsoas tendon. Thirty-five percent (7/20) of the Iliopsoas tendons was disrupted and 85% (17/20) was distorted, most commonly below the iliopectineal eminence. The majority of postoperative symptomatic patients has atrophy of the iliacus and psoas muscles and distortion and disruption of the Iliopsoas tendon and should be recognized as a normal imaging appearance following Iliopsoas tendon release.
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labral injuries due to Iliopsoas impingement can they be diagnosed on mr arthrography
American Journal of Roentgenology, 2012Co-Authors: Donna G. Blankenbaker, James S. Keene, Michael J. Tuite, Alejandro Munoz Del RioAbstract:OBJECTIVE. Iliopsoas impingement is a new arthroscopic diagnosis that refers to an anterior labral injury caused by the Iliopsoas tendon. Currently, there are no preoperative criteria to establish the diagnosis of Iliopsoas impingement. The goal of this study was to determine whether there are imaging criteria that would identify Iliopsoas impingement on preoperative MR arthrography. MATERIALS AND METHODS. This study compared the preoperative MR arthrograms of 23 patients who had Iliopsoas impingement diagnosed at hip arthroscopy with the arthrograms of 24 patients who did not have Iliopsoas impingement found at hip arthroscopy. All of the arthroscopies were performed by a single orthopedic hip surgeon. In all cases of impingement, there was an isolated injury to the labrum at the 3-o’clock position. All were treated by arthroscopic Iliopsoas tenotomy performed at the labral level. The MR examinations of the 47 patients were evaluated independently by two musculoskeletal radiologists who were blinded to t...
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Labral injuries due to Iliopsoas impingement: can they be diagnosed on MR arthrography?
AJR. American journal of roentgenology, 2012Co-Authors: Donna G. Blankenbaker, James S. Keene, Michael J. Tuite, Alejandro Munoz Del RioAbstract:Iliopsoas impingement is a new arthroscopic diagnosis that refers to an anterior labral injury caused by the Iliopsoas tendon. Currently, there are no preoperative criteria to establish the diagnosis of Iliopsoas impingement. The goal of this study was to determine whether there are imaging criteria that would identify Iliopsoas impingement on preoperative MR arthrography. This study compared the preoperative MR arthrograms of 23 patients who had Iliopsoas impingement diagnosed at hip arthroscopy with the arthrograms of 24 patients who did not have Iliopsoas impingement found at hip arthroscopy. All of the arthroscopies were performed by a single orthopedic hip surgeon. In all cases of impingement, there was an isolated injury to the labrum at the 3-o'clock position. All were treated by arthroscopic Iliopsoas tenotomy performed at the labral level. The MR examinations of the 47 patients were evaluated independently by two musculoskeletal radiologists who were blinded to the diagnosis. The following characteristics of the Iliopsoas tendon at the level of the anterior labrum were evaluated: lateral dip, increased signal intensity (SI) between the Iliopsoas tendon and labrum, irregularity of the deep margin of the Iliopsoas tendon, edema within the Iliopsoas tendon or capsule at the 3-o'clock position, presence of a labral tear at the 3-o'clock position, dimensions of the Iliopsoas tendon, and location of Iliopsoas tendon as it passed the labrum. Statistical analysis was performed using the Kruskal Wallis test, Fisher exact test, and Cohen kappa. Values for p less than 0.05 were considered significant. Nineteen women (mean age, 35 years) and four men (mean age, 36 years) had central Iliopsoas impingement. Sixteen women (mean age, 38 years) and eight men (mean age, 35 years) did not have central Iliopsoas impingement (p=0.318). For the impingement and nonimpingement groups, lateral dip of the Iliopsoas tendon was seen in 15 of 23 (65%) and 17 of 24 (71%) for reader 1 and 18 of 23 (78%) and 11 of 24 (46%) for reader 2, respectively (p=0.76 and 0.036, respectively). There was no difference between the groups for increased SI between the Iliopsoas tendon and labrum (p=0.38 and 0.82, respectively), irregular deep margin of the Iliopsoas tendon (p=0.61 and 0.35, respectively), thickness of the Iliopsoas tendon (p=0.33), or tendon or capsule edema (p=0.37 and 0.77, respectively). Reader 1 found 20 of 23 and reader 2 18 of 23 labral tears at the 3-o'clock position in the Iliopsoas impingement group, with 13 of 24 and 10 of 24 in the non-Iliopsoas impingement group respectively (p=0.024 and 0.017, respectively). The combined Iliopsoas tendon width for both readers was 10.2 mm (range, 8.1-14.3 mm) in women and 11.9 mm (range, 11.1-13.4 mm) in men in the Iliopsoas impingement group (p=0.0285), and 11.0 mm (range, 9.0-12.6 mm) for women and 11.8 mm (range, 8.7-15.1 mm) for men in the non-Iliopsoas impingement group (p=0.159). The Iliopsoas tendon most commonly crossed the labrum at the 3-o'clock position in both groups (p=0.83-0.17). An acetabular labral tear at the 3-o'clock position should suggest the diagnosis of Iliopsoas impingement.
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cross sectional analysis of Iliopsoas muscle tendon units at the sites of arthroscopic tenotomies an anatomic study
American Journal of Sports Medicine, 2011Co-Authors: Josh R Blomberg, Benjamin S Zellner, James S. KeeneAbstract:BackgroundArthroscopic Iliopsoas tenotomies are performed at the level of the labrum, femoral neck, and lesser trochanter. The composition and percentage of the Iliopsoas muscle-tendon unit (MTU) t...
Donna G. Blankenbaker - One of the best experts on this subject based on the ideXlab platform.
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MR Appearance and Clinical Significance of Changes in the Hip Muscles and Iliopsoas Tendon After Arthroscopic Iliopsoas Tenotomy in Symptomatic Patients
HSS Journal ®, 2013Co-Authors: Kendra S. Hain, Donna G. Blankenbaker, Arthur A. Smet, James S. Keene, Alejandro Munoz RioAbstract:Background Iliopsoas tenotomy is a treatment for snapping hip. Does this surgical procedure change the surrounding muscle and tendon anatomy? Questions/Purposes This study seeks to evaluate the changes in the MR appearance of the hip muscles and Iliopsoas tendon in patients following arthroscopic Iliopsoas tenotomy. Methods One hundred sixty-nine consecutive adults were evaluated after Iliopsoas tenotomy at the lesser trochanter. Each MR exam was evaluated independently by three radiologists for muscle edema, atrophy (grade 0–4), compensatory hypertrophy, signal within the Iliopsoas tendon (increased on T1 or T2 sequences), and Iliopsoas tendon morphology (distorted or disrupted) above, at, and below the iliopectineal eminence. A finding was considered positive if reported by two or three of the radiologists. Results Twenty subjects met the inclusion criteria. Muscle edema was present in 15% (3/20) of subjects within the iliacus, psoas, and quadratus femoris. Atrophy was observed in the following muscles: iliacus 85% (17/20), psoas 75% (15/20), quadratus femoris 10% (2/20), rectus femoris 5% (1/20), vastus lateralis 5% (1/20), and gluteus maximus 25% (5/20). There was no compensatory hypertrophy. Ninety percent (18/20) had increased T1 and 10% (2/20) had increased T2 signal within the Iliopsoas tendon. Thirty-five percent (7/20) of the Iliopsoas tendons was disrupted and 85% (17/20) was distorted, most commonly below the iliopectineal eminence. Conclusion The majority of postoperative symptomatic patients has atrophy of the iliacus and psoas muscles and distortion and disruption of the Iliopsoas tendon and should be recognized as a normal imaging appearance following Iliopsoas tendon release.
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MR Appearance and Clinical Significance of Changes in the Hip Muscles and Iliopsoas Tendon After Arthroscopic Iliopsoas Tenotomy in Symptomatic Patients
HSS journal : the musculoskeletal journal of Hospital for Special Surgery, 2013Co-Authors: Kendra S. Hain, Donna G. Blankenbaker, Arthur A. Smet, James S. Keene, Alejandro Munoz Del RioAbstract:Iliopsoas tenotomy is a treatment for snapping hip. Does this surgical procedure change the surrounding muscle and tendon anatomy? This study seeks to evaluate the changes in the MR appearance of the hip muscles and Iliopsoas tendon in patients following arthroscopic Iliopsoas tenotomy. One hundred sixty-nine consecutive adults were evaluated after Iliopsoas tenotomy at the lesser trochanter. Each MR exam was evaluated independently by three radiologists for muscle edema, atrophy (grade 0-4), compensatory hypertrophy, signal within the Iliopsoas tendon (increased on T1 or T2 sequences), and Iliopsoas tendon morphology (distorted or disrupted) above, at, and below the iliopectineal eminence. A finding was considered positive if reported by two or three of the radiologists. Twenty subjects met the inclusion criteria. Muscle edema was present in 15% (3/20) of subjects within the iliacus, psoas, and quadratus femoris. Atrophy was observed in the following muscles: iliacus 85% (17/20), psoas 75% (15/20), quadratus femoris 10% (2/20), rectus femoris 5% (1/20), vastus lateralis 5% (1/20), and gluteus maximus 25% (5/20). There was no compensatory hypertrophy. Ninety percent (18/20) had increased T1 and 10% (2/20) had increased T2 signal within the Iliopsoas tendon. Thirty-five percent (7/20) of the Iliopsoas tendons was disrupted and 85% (17/20) was distorted, most commonly below the iliopectineal eminence. The majority of postoperative symptomatic patients has atrophy of the iliacus and psoas muscles and distortion and disruption of the Iliopsoas tendon and should be recognized as a normal imaging appearance following Iliopsoas tendon release.
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labral injuries due to Iliopsoas impingement can they be diagnosed on mr arthrography
American Journal of Roentgenology, 2012Co-Authors: Donna G. Blankenbaker, James S. Keene, Michael J. Tuite, Alejandro Munoz Del RioAbstract:OBJECTIVE. Iliopsoas impingement is a new arthroscopic diagnosis that refers to an anterior labral injury caused by the Iliopsoas tendon. Currently, there are no preoperative criteria to establish the diagnosis of Iliopsoas impingement. The goal of this study was to determine whether there are imaging criteria that would identify Iliopsoas impingement on preoperative MR arthrography. MATERIALS AND METHODS. This study compared the preoperative MR arthrograms of 23 patients who had Iliopsoas impingement diagnosed at hip arthroscopy with the arthrograms of 24 patients who did not have Iliopsoas impingement found at hip arthroscopy. All of the arthroscopies were performed by a single orthopedic hip surgeon. In all cases of impingement, there was an isolated injury to the labrum at the 3-o’clock position. All were treated by arthroscopic Iliopsoas tenotomy performed at the labral level. The MR examinations of the 47 patients were evaluated independently by two musculoskeletal radiologists who were blinded to t...
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Labral injuries due to Iliopsoas impingement: can they be diagnosed on MR arthrography?
AJR. American journal of roentgenology, 2012Co-Authors: Donna G. Blankenbaker, James S. Keene, Michael J. Tuite, Alejandro Munoz Del RioAbstract:Iliopsoas impingement is a new arthroscopic diagnosis that refers to an anterior labral injury caused by the Iliopsoas tendon. Currently, there are no preoperative criteria to establish the diagnosis of Iliopsoas impingement. The goal of this study was to determine whether there are imaging criteria that would identify Iliopsoas impingement on preoperative MR arthrography. This study compared the preoperative MR arthrograms of 23 patients who had Iliopsoas impingement diagnosed at hip arthroscopy with the arthrograms of 24 patients who did not have Iliopsoas impingement found at hip arthroscopy. All of the arthroscopies were performed by a single orthopedic hip surgeon. In all cases of impingement, there was an isolated injury to the labrum at the 3-o'clock position. All were treated by arthroscopic Iliopsoas tenotomy performed at the labral level. The MR examinations of the 47 patients were evaluated independently by two musculoskeletal radiologists who were blinded to the diagnosis. The following characteristics of the Iliopsoas tendon at the level of the anterior labrum were evaluated: lateral dip, increased signal intensity (SI) between the Iliopsoas tendon and labrum, irregularity of the deep margin of the Iliopsoas tendon, edema within the Iliopsoas tendon or capsule at the 3-o'clock position, presence of a labral tear at the 3-o'clock position, dimensions of the Iliopsoas tendon, and location of Iliopsoas tendon as it passed the labrum. Statistical analysis was performed using the Kruskal Wallis test, Fisher exact test, and Cohen kappa. Values for p less than 0.05 were considered significant. Nineteen women (mean age, 35 years) and four men (mean age, 36 years) had central Iliopsoas impingement. Sixteen women (mean age, 38 years) and eight men (mean age, 35 years) did not have central Iliopsoas impingement (p=0.318). For the impingement and nonimpingement groups, lateral dip of the Iliopsoas tendon was seen in 15 of 23 (65%) and 17 of 24 (71%) for reader 1 and 18 of 23 (78%) and 11 of 24 (46%) for reader 2, respectively (p=0.76 and 0.036, respectively). There was no difference between the groups for increased SI between the Iliopsoas tendon and labrum (p=0.38 and 0.82, respectively), irregular deep margin of the Iliopsoas tendon (p=0.61 and 0.35, respectively), thickness of the Iliopsoas tendon (p=0.33), or tendon or capsule edema (p=0.37 and 0.77, respectively). Reader 1 found 20 of 23 and reader 2 18 of 23 labral tears at the 3-o'clock position in the Iliopsoas impingement group, with 13 of 24 and 10 of 24 in the non-Iliopsoas impingement group respectively (p=0.024 and 0.017, respectively). The combined Iliopsoas tendon width for both readers was 10.2 mm (range, 8.1-14.3 mm) in women and 11.9 mm (range, 11.1-13.4 mm) in men in the Iliopsoas impingement group (p=0.0285), and 11.0 mm (range, 9.0-12.6 mm) for women and 11.8 mm (range, 8.7-15.1 mm) for men in the non-Iliopsoas impingement group (p=0.159). The Iliopsoas tendon most commonly crossed the labrum at the 3-o'clock position in both groups (p=0.83-0.17). An acetabular labral tear at the 3-o'clock position should suggest the diagnosis of Iliopsoas impingement.
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Iliopsoas musculotendinous unit.
Seminars in musculoskeletal radiology, 2008Co-Authors: Donna G. Blankenbaker, Michael J. TuiteAbstract:Hip pain is a common condition with many etiologies, and the workup often includes imaging. The Iliopsoas musculotendinous unit is becoming more frequently recognized as the culprit for hip pain, partially due to the increase in athletic activity in the general population as well as to the increased demand in professional sports. Iliopsoas tendon injuries are also seen in the elderly population and documented as occurring following total hip replacement. Iliopsoas diseases, often overlooked as a cause of hip pain, include tendinosis, snapping tendon, bursitis, tears, and avulsion injuries. This article reviews the normal magnetic resonance imaging and sonographic anatomy of the Iliopsoas musculotendinous unit and the imaging characteristics of diseases that involve the Iliopsoas musculotendinous unit. We review the causes of a snapping hip and the role of sonography in evaluating and guiding treatment of the snapping Iliopsoas tendon.
Benjamin G. Domb - One of the best experts on this subject based on the ideXlab platform.
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Arthroscopic Technique for Iliopsoas Fractional Lengthening for Symptomatic Internal Snapping of the Hip, Iliopsoas Impingement Lesion, or Both.
Arthroscopy techniques, 2018Co-Authors: Sivashankar Chandrasekaran, Mary R. Close, John P. Walsh, Edwin O. Chaharbakhshi, Parth Lodhia, Mitchell R. Mohr, Benjamin G. DombAbstract:Abstract Pathology of the Iliopsoas may cause painful internal snapping of the hip or labral damage from soft impingement. Favorable outcomes have been reported after arthroscopic release or fractional lengthening of the Iliopsoas. In patients with risk factors for instability, restoration of other soft-tissue constraints such as the labrum and capsule should be performed if Iliopsoas fractional lengthening is undertaken. The purpose of this article is to detail the step-by-step surgical technique of arthroscopic Iliopsoas fractional lengthening, in addition to the indications, pearls, and pitfalls of the technique.
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Endoscopic Iliopsoas Tenotomy for Iliopsoas Impingement on a Collared Femoral Prosthesis
Arthroscopy techniques, 2013Co-Authors: Dror Lindner, Christine E. Stake, Youssef F. El Bitar, Timothy J. Jackson, Benjamin G. DombAbstract:Groin pain after total hip replacement is an uncommon event and may be the result of several causes, including Iliopsoas impingement. We describe the case of a 51-year-old woman who was diagnosed with Iliopsoas impingement after total hip replacement with a collared femoral stem. She did not improve despite extensive conservative treatment. She was treated by endoscopic Iliopsoas tenotomy, and the surgical technique is described herein. Her preoperative groin pain and popping disappeared completely at 3 months postoperatively.
Brandon Whitcher - One of the best experts on this subject based on the ideXlab platform.
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Large-Scale Analysis of Iliopsoas Muscle Volumes in the UK Biobank
Scientific reports, 2020Co-Authors: Julie Fitzpatrick, Nicolas Basty, Madeleine Cule, Yi Liu, Jimmy D. Bell, E. Louise Thomas, Brandon WhitcherAbstract:Psoas muscle measurements are frequently used as markers of sarcopenia and predictors of health. Manually measured cross-sectional areas are most commonly used, but there is a lack of consistency regarding the position of the measurementand manual annotations are not practical for large population studies. We have developed a fully automated method to measure Iliopsoas muscle volume (comprised of the psoas and iliacus muscles) using a convolutional neural network. Magnetic resonance images were obtained from the UK Biobank for 5,000 male and female participants, balanced for age, gender and BMI. Ninety manual annotations were available for model training and validation. The model showed excellent performance against out-of-sample data (dice score coefficient of 0.912 +/- 0.018). Iliopsoas muscle volumes were successfully measured in all 5,000 participants. Iliopsoas volume was greater in male compared with female subjects. There was a small but significant asymmetry between left and right Iliopsoas muscle volumes. We also found that Iliopsoas volume was significantly related to height, BMI and age, and that there was an acceleration in muscle volume decrease in men with age. Our method provides a robust technique for measuring Iliopsoas muscle volume that can be applied to large cohorts.
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large scale analysis of Iliopsoas muscle volumes in the uk biobank
Scientific Reports, 2020Co-Authors: Julie Fitzpatrick, Nicolas Basty, Madeleine Cule, Yi Liu, Jimmy D. Bell, Louise E Thomas, Brandon WhitcherAbstract:Psoas muscle measurements are frequently used as markers of sarcopenia and predictors of health. Manually measured cross-sectional areas are most commonly used, but there is a lack of consistency regarding the position of the measurement and manual annotations are not practical for large population studies. We have developed a fully automated method to measure Iliopsoas muscle volume (comprised of the psoas and iliacus muscles) using a convolutional neural network. Magnetic resonance images were obtained from the UK Biobank for 5000 participants, balanced for age, gender and BMI. Ninety manual annotations were available for model training and validation. The model showed excellent performance against out-of-sample data (average dice score coefficient of 0.9046 ± 0.0058 for six-fold cross-validation). Iliopsoas muscle volumes were successfully measured in all 5000 participants. Iliopsoas volume was greater in male compared with female subjects. There was a small but significant asymmetry between left and right Iliopsoas muscle volumes. We also found that Iliopsoas volume was significantly related to height, BMI and age, and that there was an acceleration in muscle volume decrease in men with age. Our method provides a robust technique for measuring Iliopsoas muscle volume that can be applied to large cohorts.
Josh R Blomberg - One of the best experts on this subject based on the ideXlab platform.
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cross sectional analysis of Iliopsoas muscle tendon units at the sites of arthroscopic tenotomies an anatomic study
American Journal of Sports Medicine, 2011Co-Authors: Josh R Blomberg, Benjamin S Zellner, James S. KeeneAbstract:BackgroundArthroscopic Iliopsoas tenotomies are performed at the level of the labrum, femoral neck, and lesser trochanter. The composition and percentage of the Iliopsoas muscle-tendon unit (MTU) t...
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Cross-sectional analysis of Iliopsoas muscle-tendon units at the sites of arthroscopic tenotomies: an anatomic study.
The American journal of sports medicine, 2011Co-Authors: Josh R Blomberg, Benjamin S Zellner, James S. KeeneAbstract:Arthroscopic Iliopsoas tenotomies are performed at the level of the labrum, femoral neck, and lesser trochanter. The composition and percentage of the Iliopsoas muscle-tendon unit (MTU) that is released when the tendon is cut at these sites has not been reported to date. Cutting the Iliopsoas tendon at the 3 common sites of arthroscopic tenotomies does not release the entire Iliopsoas MTU. Descriptive laboratory study. Forty Iliopsoas MTUs from 20 embalmed cadavers were isolated at the level of the hip joint and released from their insertion on the lesser trochanter. Circumferential measurements of the composite MTU and the isolated Iliopsoas tendon were then made at (1) the MTU's insertion on the lesser trochanter, (2) the Wettstein et al site of transcapsular release, and (3) the Alpert et al release site at the level of the labrum. Single proportion testing was performed using the Student t test to determine if significant differences existed between the average circumference of the Iliopsoas MTUs or the isolated tendons at the 3 levels at which they were measured. The average circumference of the Iliopsoas-muscle belly complex at the level of the labrum, the transcapsular release site, and the lesser trochanter was 68, 58, and 46 mm, respectively. The average circumference of the Iliopsoas tendon at these same levels was 27, 31, and 27 mm, respectively. Thus, at the level of the labrum, transcapsular release site, and lesser trochanter, the Iliopsoas MTU is composed of 40% tendon/60% muscle belly, 53% tendon/47% muscle belly, and 60% tendon/40% muscle belly, respectively. Cutting the Iliopsoas tendon at the labrum, head-neck junction, or lesser trochanter does not result in a release of the entire Iliopsoas MTU. The results of this study document that releasing the Iliopsoas tendon at the lesser trochanter preserves 40% of the MTU and does not result in a complete detachment of the Iliopsoas MTU.
