femoroacetabular impingement (FAI) and labral tears. No patient in this group had ... measurements for hip flexion were taken pre-operatively for bilateral hips in ...
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2013 ISAKOS ABSTRACTS
years; range 12-61) who underwent an arthroscopic fractional lengthening of the iliopsoas tendon at the musculotendinous junction in combination with treatment of femoroacetabular impingement (FAI) and labral tears. No patient in this group had undergone any known hip arthroscopy on the contralateral hip. A control group of 50 patients (average age 37.8 years; range 15-58) undergoing similar arthroscopic procedures without an iliopsoas lengthening was also identified. Strength and torque measurements for hip flexion were taken pre-operatively for bilateral hips in three separate measurements using a dynamometer. A ratio for hip extension to flexion was also calculated. These measurements were repeated post operatively in a similar fashion at an average of 4.3 months (range 1.9-25.2) postoperatively. Results: Preoperatively, patients who require psoas release have significant lower strength(difference between normal vs inj)(13 vs 3.9)(p¼0.001), significantly lower torque(24 vs 8.9)(difference between normal vs inj)(p¼0.004), and significantly lower flexion/extension ratio((difference between normal vs. inj)(p¼0.036). These differences are not seen postoperatively. Individually, psoas patients show significant improvement between preop and postop(strength 3.9 to 12.7; torque8.9 to 24.1) while control patients did not. Postoperatively, strengths were similar between psoas release and control groups. Conclusion: This study showed that arthroscopic fractional lengthening of the iliopsoas tendon at the musculotendinous junction did not lead to a loss of hip flexion strength or torque. Patients undergoing psoas release start with significantly increased deficits in strength and torque, but show similar strength to patients undergoing arthroscopy for FAI and labral tears postoperatively. Paper #221: Hip and Pelvic Kinematics in FAI Patients Differs Between Constrained and Unconstrained Squatting KATHARINE J. WILSON, MASC, USA PRESENTING AUTHOR JOHAN ERIK GIPHART, PHD, USA KERRY COSTELLO, MS, USA MICHAEL J. DECKER, PHD, USA BRUNO GONÇALVES SCHRODER E SOUZA, MD, MS, BRAZIL MARC J. PHILIPPON, MD, USA $ Steadman Philippon Research Institute, Vail, CO, USA
SUMMARY Hip and pelvic kinematics in FAI patients differs between constrained and unconstrained squatting. Squatting methods need to be standardized for accurate comparisons of results in the literature. ABSTRACT DATA Introduction: Maximal depth squatting is an exercise that approaches the extremes of hip joint motion and has been used to evaluate hip and pelvic kinematics. In patients with femoroacetabular impingement (FAI), maximal depth squatting has been used to evaluate whether patients have altered kinematics to compensate for their injury. Many patients with FAI have difficulty with combined high flexion and internal rotation angles, and have been theorized to
abduct their hip during squatting to avoid the bony conflict. Therefore, constraining the squat to strictly the sagittal plane may emphasize the altered kinematics in these patients. The goal of this study was to investigate hip and pelvic kinematics during constrained and unconstrained squatting, and identify functional adaptations in FAI patients. It was hypothesized that unconstrained squatting would allow FAI patients to squat deeper and with greater hip abduction than during constrained squatting. Methods: This study was approved by the governing Institutional Review Board and all participants gave their written informed consent prior to participating. Fourteen patients diagnosed with FAI were recruited to participate in this study (age: 28.0 5.8 years, height: 179.0 9.2 cm, weight: 80.4 12.2 kg, 12 M, 2 F). Participants performed two squatting motions, starting from standing with their feet shoulder width apart and both arms extended, squatting down to a maximal depth, and returning to a standing position at a self-selected pace while maintaining heel contact throughout the movement. For the first type of squat, no additional directions were given (unconstrained squat). For the constrained squat, the participants were given the additional constraint that their feet had to remain parallel to each other and their knees had to track directly over their toes which limited this motion to the sagittal plane only. Kinematics was determined using a 10-camera motion capture system (Eagle, Motion Analysis Corp, Santa Clara, CA) and The MotionMonitor software (Innsport, Chicago, IL, USA). The maximum squat depth was expressed as a percentage of the height of the marker placed on the sacrum during neutral stance. Hip flexion, abduction, and internal rotation angles were calculated relative to the pelvis, and the orientation of the pelvis relative to the laboratory floor was also calculated. All angular measurements were made at a standardized depth of 75% of the neutral stance height to account for differences in maximum squat depth. Matched pairs t-tests were used to compare squat depth and angular measurements between constrained and unconstrained squatting. Results: Kinematic differences were found between constrained and unconstrained squatting, specifically in squat depth, hip abduction, hip internal rotation and pelvic rotation in the frontal plane. The maximum squat depth was significantly different between unconstrained and constrained squatting (46.0 15.1% and 60.2 12.8% of stance height, respectively; p < 0.001). Additionally, unconstrained squatting allowed greater hip abduction than constrained squatting (12.9 23.9 and 8.0 24.0 , respectively; p < 0.010), and less internal rotation (9.2 9.6 ; and 12.0 8.5 , respectively; p < 0.050) at 75% of stance height. While not significant, increased pelvic rotation in the frontal plane was found during constrained squatting compared to unconstrained squatting (12.3 10.3 and 10.9 8.9 , respectively; p ¼ 0.071). Discussion: Our hypothesis that FAI patients would squat deeper during unconstrained squatting than constrained squatting was confirmed. Constrained squatting required greater internal rotation and less hip abduction, which is expected when the squatting motion is limited to the sagittal plane. Increased pelvic rotation was found in the frontal plane during constrained squatting, which could be due to
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relying on a dominant leg to maintain form and balance. These findings suggest that the squatting method can greatly influence kinematic results, and should be taken into account in future studies of squatting kinematics. Significance: Squatting methods need to be standardized across the literature. Hip and pelvic kinematics differ between constrained and unconstrained squatting in FAI patients, and the details of the squatting method should be described in the literature to allow accurate comparisons of the results.
Conclusion: This is the first known study describing the overall microstructure of the ligamentum teres (and its neural elements) with the use of fresh human specimens. Based on our findings, the ligamentum teres should no longer be considered a developmental vestige, as there is evidence to show that it has both mechanical and biological functions within the hip joint. Surgical procedures involving the hip joint should aim to minimize trauma or damage to the ligamentum teres, so as to limit any potential loss of function within the joint.
Paper #222: Histology of the Ligamentum Teres of the Hip: A Basic Science Study BRYAN WANG, MBBS, MRCS (EDIN), SINGAPORE PRESENTING AUTHOR KONG BING TAN, MBBS, MRCPATH, FRCPA, SINGAPORE JAMES LOH, MBBS, FRCS (EDIN), FRCS (ORTHO), SINGAPORE $ Changi General Hospital, Singapore, Singapore
Paper #223: Treatment of Isolated Ligamentum Teres (LT) Partial Tears By Debridement with the Addition of Capsular Tightening Prevents Tear Recurrence TOMAS AMENABAR, MD, CHILE PRESENTING AUTHOR JOHN M. O’DONNELL, MBBS, FRACS (TR&ORTHOP), AUSTRALIA $ St Vincent’s Private Hospital, Melbourne, VIC, Australia
SUMMARY A basic science study describing the histopathological features of the ligamentum teres of the hip in fresh human specimens. ABSTRACT DATA Background and Aim: There have been several studies done on the ligamentum teres of the hip, yet little has been elucidated as to its true function, with many considering it to be a predominantly vestigial structure in adult hips. However, recent studies have shown possible mechanical and biological roles in the function of the hip joint, and the increasing use of hip arthroscopy has shown that injury to the ligamentum teres does have a contributory role in patients with chronic hip pain. This study is in essence a basic science study looking at the microstructure of the ligamentum teres, with special emphasis on the presence and distribution of nerve bundles. Our study aims to correlate the microstructure of the ligamentum teres with its postulated functions, allowing greater understanding of its role and guiding treatment principles in pathologies involving the ligamentum teres. Methods: Fresh specimens were excised intraoperatively in 12 patients undergoing hip procedures. They were then preserved in formalin solution and subsequently sent to the laboratory for histological analysis by our collaborating pathologist. The specimens were sectioned and stained, and subsequently examined under the microscope to look at their microstructure. In addition, special staining techniques were employed to look for nerve tissue within the ligamentum teres specimens. Results: The ligamentum teres of the hip is composed predominantly of a connective tissue matrix of collagen fibres, fibrous and adipose tissue, with an overlying layer of investing synovium. In addition, there are blood vessels of varying sizes surrounded by a layer of encircling fat. All specimens examined showed the presence of nerve bundles of varying shapes and sizes, confirming our hypothesis that the ligamentum teres of the hip does contain neural elements which may serve different functions and Purposes within the hip joint. There were also some specimens which showed presence of metaplastic change, possibly as a result of ongoing adaptive processes.
SUMMARY Previously treatment of partial thickness Ligamentum Teres tears gave excellent outcomes, but was associated with a 17% tear recurrence rate. However the addition of anterior capsule tightening has maintained the excellent outcomes whilst completely eliminating tear recurrence at mid term follow up. ABSTRACT DATA Introduction: Ligamentum Teres (LT) is now recognized as an important structure of hip joint. The prevalence of LT tears in hip arthroscopies has been reported between 8% and 51%, and LT tears are clearly recognized as a cause of hip pain. The most commonly recommended method of treatment of LT tears is debridement; this has been shown to be reliable, improving symptoms and relieving pain, although we have previously reported the recurrence rate of isolated tears with debridement alone is 17%. Our hypothesis is that the recurrence of LT tears is due to the persistance of ligamentous laxity and hip microinstability. We believe that to obtain a more stable joint by tightening the anterior capsule will diminish the recurrence rate of LT tears. Methods: Retrospective review of the surgical database from the senior author from June 2009 to August 2011. The indication for hip arthroscopy was patients with a history of hip pain, with or without mechanical symptoms, which did not respond to conservative treatment. The inclusion criteria were all the patients who underwent hip arthroscopy and had an isolated (no other intra-articular pathology) partial LT tear. Arthroscopically the tear was debrided with a thin flexible radiofrequency probe and the joint capsule was tighten either by radiofrequency shrinkage or suture plication. All the patients undergoing hip arthroscopy were prospectively assessed with the Modified Harris Hip Score (MHHS) and the Non Arthritic Hip Score (NAHS). Following surgery these Outcome Measures were repeated at 6 weeks, 6 months, and then annually. Results: 1574 hip arthroscopies were performed by the senior author from June 2009 to November 2011, and in 684 (43%) LT tears were identified. Partial LT tears were present in 619 (90%) and complete LT tears were found in
