Hip Flexion Position Research Articles

Effect of initial position on the muscle activity of the hip extensors and amount of pelvic tilt during prone hip extension.

[Purpose] The aim of this study was to identify the effects of initial position of the hip joint with changes in the hip joint angle on the respective muscle activities of the bilateral erector spinae (ES), unilateral gluteus maximus (GM), and biceps femoris (BF) and the amount of pelvic anterior tilt during prone hip extension (PHE). [Subjects] Fifteen healthy volunteers were enrolled in this study. [Methods] The subjects performed PHE in three positions: neutral, 20°, and 45° flexed hip joint. The activities of the ES, GM, and BF were measured using surface electromyography, and kinematic values for pelvic anterior tilt were calculated using a motion capture system. [Results] There was a significant decrease in muscle activity of the contralateral ES at 45°, and an increase in the GM muscle activity and decrease in the BF muscle activity at 20°. The amount of pelvic anterior tilt was lower at 20°. [Conclusion] These results suggest that a hip flexion position of 20° would have an advantage over the other measured positions.

Normative Adductor Squeeze Test Values in Elite Junior Rugby Union Players

To establish normative adductor squeeze test (AST) values in elite junior rugby union players and investigate if differences existed between field position units and categorizations. Cross-sectional study. National underage screening camp. One hundred four healthy players attending an under-19 and under-18 national musculoskeletal and fitness screening camp. Players had no history of surgery, no self-reported history of groin or pelvic pain in either limb and no other lower limb injury in the past 3 months, and no pain reported during the testing procedure. The AST in 3 positions of hip flexion (0, 45, and 90 degrees), position unit, and categorizations. The highest AST values were observed at 45 degrees of hip flexion in all field position categories. No differences were observed between position units and categorizations. Normative AST values in an elite junior rugby union population were established in this investigation. Clinically, the sports medicine professional may use these results in making decisions on the management of both symptomatic and asymptomatic players.

Hip Rotator Strength in Healthy Young Adults Measured in Hip Flexion and Extension by Using a Hand-held Dynamometer

To investigate the effect of hip joint position on hip rotator muscle strength of healthy young adults by using a hand-held dynamometer. A cross-sectional cohort study. A university medical center. Thirty-four healthy (19 women, 15 men; mean [standard deviation] age, 25± 2.3 years) participated in this study. A hand-held dynamometer was used to measure the strength of hip internal rotators and external rotators in 2 positions: hip flexion in sitting and hip extension in supine. The hip was tested in a neutral position with respect to rotation, abduction, and adduction. Isometric force in pounds was measured as the subject pushed against the device. For each subject, hip rotator muscle strength measurements were taken during a single session. Hypotheses were developed before data collection. Hip internal rotators were significantly stronger in hip flexion compared with hip extension (P< .01). There was no significant difference found in the hip external rotators between the 2 positions. Hip internal rotators and external rotators behave differently when comparing strength measurements between the positions of hip flexion and hip extension. A hand-held dynamometer provided an objective measurement of strength that was clinically feasible to use. Both muscle length and moment arms influence forceproduction of the hip rotators as the hip position changes. Understanding these relationships may help clinicians interpret strength findings and direct intervention toward strengthening the appropriate muscles by using the most advantageous position.

Flexion Gap Measured in 45 Degrees and 90 Degrees of Hip Flexion Positions during Total Knee Arthroplasty: Measurement by Navigation System.

PurposeTo evaluate the influence of thigh weight in different hip flexion positions on the knee flexion gap in total knee arthroplasty (TKA).Materials and MethodsWe evaluated 20 patients (25 knees) with osteoarthritis of the knee that underwent TKA using a navigation system from May 2010 to April 2011. After posterior cruciate ligament sacrificing, complete soft tissue balancing, and fixation of all components with cement, the flexion gaps were measured with the patello-femoral joint reduced. Medial and lateral flexion gaps were measured separately in both the 90°-90° and 45°-90° flexion positions of the hip-knee joints.ResultsThe medial and lateral flexion gaps in the 45°-90° flexion position of the hip-knee joints were 13.02±2.17 mm and 13.12±2.21 mm, respectively. The medial and lateral flexion gaps in the 90°-90° flexion position were 12.92±2.03 mm and 13.08±2.29 mm, respectively. The flexion gaps showed no significant (p>0.05) differences between the two different hip flexion positions.ConclusionsFlexion gaps in TKA were not influenced by hip flexion positions (45° or 90° of flexion). Therefore, soft tissue balancing and polyethylene thickness should not be affected by hip flexion positions during TKA.

Postural control strategies during single limb stance following acute lateral ankle sprain

BackgroundSingle-limb stance is maintained via the integration of visual, vestibular and somatosensory afferents. Musculoskeletal injury challenges the somatosensory system to reweight distorted sensory afferents. This investigation supplements kinetic analysis of eyes-open and eyes-closed single-limb stance tasks with a kinematic profile of lower limb postural orientation in an acute lateral ankle sprain group to assess the adaptive capacity of the sensorimotor system to injury. MethodsSixty-six participants with first-time acute lateral ankle sprain completed a 20second eyes-open single-limb stance task on their injured and non-injured limbs (task 1). Twenty-three of these participants successfully completed the same 20second single-limb stance task with their eyes closed (task 2). A non-injured control group of 19 participants completed task 1, with 16 completing task 2. 3-dimensional kinematics of the hip, knee and ankle joints, as well as associated fractal dimension of the center-of-pressure path were determined for each limb during these tasks. FindingsBetween trial analyses revealed significant differences in stance limb kinematics and fractal dimension of the center-of-pressure path for task 2 only. The control group bilaterally assumed a position of greater hip flexion compared to injured participants on their side-matched “involved”(7.41 [6.1°] vs 1.44 [4.8]°; η2=.34) and “uninvolved” (9.59 [8.5°] vs 2.16 [5.6°]; η2=.31) limbs, with a greater fractal dimension of the center-of-pressure path (involved limb=1.39 [0.16°] vs 1.25 [0.14°]; uninvolved limb=1.37 [0.21°] vs 1.23 [0.14°]). InterpretationBilateral impairment in postural control strategies present following a first time acute lateral ankle sprain.

ACUTE ANKLE SPRAIN INJURY ALTERS KINEMATIC AND CENTRE OF PRESSURE MEASURES OF POSTURAL CONTROL DURING SINGLE LIMB STANCE

BackgroundUpright single-limb stance (SLS) is maintained via integration of visual, vestibular and somatosensory afferents. The presence of redundancies between these afferents allows the sensorimotor system to simplify a specific task...

The mini postero-postero-lateral mini incision in total hip arthroplasty

Mini invasive incisions in THA and femoral hip prostheses tend to minimise healing and recovery time. We have used a very posterior approach with technical modifications and precise skin landmarks to decrease surgical complexity, and we describe this experience here. From 2010 to 2012, 140 patients aged 79 years (range 53-93 years) were operated upon by the same surgeon in a continuous series using the same minimally invasive skin incision and six different types of implants. The incision was very posterior in the hip allowing direct visualisation of the acetabulum in the hip flexion position and visualisation of the femoral shaft extremity in a leg flexion position. The mean operating time was 100 minutes (range 75-110 min). Estimated blood loss was 385 cc (20-585 cc). Twenty-six patients had blood transfusion. The mean hospital stay was 6.8 days (5-20 days) including the time waiting for a rehabilitation centre. No operative complications related to the technique were recorded. On the postoperative radiograph, the femoral stem was aligned with the femoral axis within 3° in all patients. The mean acetabular angle to the ground plane was 40° (35-48°). No patient had a leg length discrepancy of more than four millimetres. The mean skin incision length was seven centimetres (six to eight centimetres). All patients were seen at the clinic after six weeks and the data were unchanged at this time point. The method and skin landmarks we describe appear to be a safe way to perform minimally invasive total hip replacement.

Effect of Hip Position and Gender on Active Hip Internal Rotation and External Rotation on the Dominant Side

Objective: This study was designed to establish the influence of gender and hip flexion position on active range of motion of the hip in external and internal rotation. Method: 100 (50 Males & 50 Females) healthy college-age subjects with no previous hip problems were studied. Mean age was 21.8 years with a range of 18-27 years. Hip rotation of the dominant leg of each subject was measured in the prone (hip near 0 of flexion) and seated (hip near 90 of flexion) positions using a standard goniometer. Result: Data were analyzed using t test. Our results indicate Mean values of active hip ROM for college aged students is 27.85 for internal rotation and 34.61 for external rotation in seated position & Mean values of active hip ROM for college aged students is 35.35 for internal rotation & 42.57 for external rotation in prone position.Females had statistically more active hip internal and external rotation than males. Conclusion: These findings are clinically significant and stress the importance of documenting measurement position.

Effect of body position and type of stretching on hamstring flexibility

Background and objective: Stretching exercise protocols, as part of outpatient treatment or home exercise programs, are used to improve muscle flexibility. So, the aim of the study was to examine the body position effect (standing and supine) and dynamic range of motion (DROM) stretching technique on hamstring flexibility. Material and Methods: Seventy five subjects with decreased flexibility of hamstring (defined as ≥30° loss of active knee extension, from 90°hip flexion position), participants were randomly assigned to one of three equal groups. The first group performed static stretch from standing for 30 sec. The second group performed static stretch from supine for 30 sec. The third group performed DROM stretch. The stretching procedure conducted three times per week for four weeks. Results: There was a significant increase in the knee extension range of motion for standing, supine and DROM stretch (p 0.05). Conclusion: Both standing and supine stretches displayed improvement in the hamstring flexibility, and both of them produced higher improvement than DROM stretch during hamstring flexibility training

Biomechanical Study of Patient Positioning

The objective of this study was to use finite element model (FEM) simulations and experimental testing to study the relationship between lower limb positioning for surgeries of the spine and changes in sagittal curves. Four volunteers underwent lower limb flexibility and range of motion testing before being placed prone on a new surgical frame where lateral radiographs of their spines were taken in positions of hip flexion (average 48 degrees) and extension (average 13 degrees). Personalized FEMs were created representing each volunteer's spine, rib cage, pelvis, and lower limbs. Optimization of model behavior was performed by adjustment of lower limb muscle initial strains. The FEMs were exploited to examine the impact of more extreme and intermediate lower limb positions; 30 degrees of hip extension to 90 degrees of flexion at intervals of 20 degrees. With increased hip flexion, lordosis and kyphosis decreased to an average of 52% (35 degrees) and 16% (6 degrees), respectively. Personalization of the 4 FEMs allowed reproduction of the experimental results within 5 degrees and their subsequent exploitation showed the linear changes in lordosis and kyphosis between extreme positions decreasing an average of 84% (59 degrees) and 34% (13 degrees) with increased hip flexion. A strong correlation was found between experimental change in lordosis and individual hamstring flexibilities (R=-0.93) which allowed for the development of a predictive equation for lordosis in terms of hip flexion which factors straight leg raise test results. Knowledge gained through this study can be used to improve intraoperative control of sagittal curves through lower limb positioning.

Differences of Isometric Internal and External Hip Rotation Torques among Three Different Hip Flexion Positions

Differences of Isometric Internal and External Hip Rotation Torques among Three Different Hip Flexion Positions

Dynamic Displacement of the Femoral Head by Hamstring Stretching in Children With Cerebral Palsy

Hamstring stretching is an integral component in the treatment for knee flexion contracture in cerebral palsy (CP). As hamstrings span across hip and knee joints, passive stretching of hamstrings applies force to the hip that is often dysplasia in CP. The purpose of this study is to measure the dynamic displacement of femoral head produced by passive stretching of hamstrings and to determine the factors associated with the phenomenon. Children with spastic CP were studied using computerized tomography (CT) of the pelvis. Two sets of CT studies were carried out, one with the knee flexed and the hip flexed (resting) and the other with the knee extended and the hip flexed to simulate manual hamstrings stretching. The distance from pelvic baseline to the posterior margin of femoral epiphysis was measured on the CT images and compared between resting and stretching for dynamic displacement. The dynamic displacement of the femoral head was expressed by a ratio to femoral epiphysis diameter. Twenty-seven CP children had CT studies at a mean age of 6.8 years (range: 4.5 to 9.6 y). Ten children were ambulators with or without devices and the other 17 children were nonambulators. On plain radiographs of the pelvis, the mean Reimer's migration percentage was 39% (range: 13% to 92%). On CT scan, dynamic displacement by stretching was 4.7% (range: -3.8% to 16.1%) of femoral epiphysis diameter (P<0.001 by paired t test). The displacement in the 33 hips with migration percentage of greater than 30% was significantly greater than the displacement in the other 21 hips with migration percentage of less than 30% (7.4% vs. 0.5%, P=0.001). Passive stretching of spastic hamstrings in the hip flexion position resulted in dynamic posterior displacement of the femoral head. Medical professionals should be aware of this fact, especially in spastic CP children with a higher migration percentage on radiograph. Diagnostic II.

Changes in Abdominal Vascular Tension Associated With Various Leg Positions in the Anterior Lumbar Approach

A descriptive cadaveric study measuring arterial tension. Anterior lumbar surgery is technically challenging due to perioperative vascular complications. Many studies suggest approaches based on the anatomy of the abdominal vessel for safe vascular mobilization. However, the tension in the vascular structure is also important for adequate exposure of the target lesion. It has been established that the tension in the lumbar nerve at the root level can be changed by a straight leg raise test and that the structure of the vascular connection is similar to that of the neural connection. Consequently, a change in leg position could affect the tension of lumbosacral vessels. The purpose of this study was to evaluate the effect of leg position on the tension of lumbosacral vessels. We dissected 10 unembalmed cadavers using the method described by Gumbs et al, using the Synframe system to expose the abdominal artery and vein. The left iliac artery and the distal abdominal aorta were retracted to the right side at the L4-L5 disc level by a measuring retractor to which a strain gauge was attached. The tension was checked at various angles of the hip joint and the motions of the abdominal arteries were monitored in 4 unembalmed cadavers using a C-arm fluoroscope. The tension in the abdominal aorta at L4-L5 level was decreased by 2.9% to 21.8% in the hip-flexion position, and the motion of the arteries showed proximal displacement of the external iliac artery and the common iliac artery during the hip-flexed position and veins also showed the same pattern of displacement as artery. The results of this study would be useful for not only spinal surgery but also other vascular surgeries, particularly, in cases where patients with conditions such as atherosclerosis or stenosis.

The effects of Posture on seat-to-head Whole-Body Vibration Transmission

Five male subjects were exposed to root-mean-square whole-body vibration (WBV) acceleration levels ranging from 0.011m/s2 to 0.615m/s2 while seated on a vibration simulator. During the WBV exposure, subjects adopted 5 unsupported trunk flexion/extension positions (15, 10, 0, −10 and −15, ±2.5 degrees from vertical), and 4 hip flexion positions (−10, 0, 10, and 20 degrees from the horizontal). WBV measurements were taken with a tri-axial accelerometer at the buttock/seat interface and the head. Hydrostatic weighing was also conducted to determine the subject's adipose content. Adipose content of the individual had no significant relationship with the seat-to-head transmission of vibration. Vibration exposures at 4Hz had significantly more transmission than vibration exposures at 6.3Hz. Vibration exposures in the Z-axis (vertical) had significantly more vibration transmission than vibration exposures in the X- (front-to-back) and Y-axes (left-to-right). A significant interaction was also found between trunk position, frequency and axis of exposure.

P17. The Effect of Intraoperative Position in Short-segment Posterior Lumbar Interbody Fusion on Maintenance of Lumbar Lordosis

BACKGROUND CONTEXT: Preservation of lordosis during instrumented lumbar fusion is critical for maintenance of normal sagittal balance. Many authors have demonstrated that lumbar lordosis is reduced in the hip flexion position, but little information exists whether the decreased lumbar lordosis and segmental lordosis adversely affects the maintenance of lumbar lordosis in short-segment PLIF postoperatively.

Skin movement errors in measurement of sagittal lumbar and hip angles in young and elderly subjects

Errors in measurement of sagittal lumbar and hip angles due to skin movement on the pelvis and/or lateral thigh were measured in young ( n = 21, age = 18.6 ± 2.1 years) and older ( n = 23, age = 70.9 ± 6.4 years) age groups. Skin reference markers were attached over specific landmarks of healthy young and elderly subjects, who were videotaped in three static positions of hip flexion using the 2D PEAK Motus video analysis system. Sagittal lumbar and hip angles were calculated from skin reference markers and manually palpated landmarks. The elderly subjects demonstrated greater errors in lumbar angle due to skin movement on the pelvis only in the maximal hip flexion position. The traditional model (ASIS-PSIS-GT-LFE) underestimated sagittal hip angle and the revised model (ASIS-PSIS-2/3Th-1/4Th) provided more accurate measurement of sagittal hip angle throughout the full available range of hip flexion. Skin movement on the pelvis had a small counterbalancing effect on the larger errors from lateral thigh markers (GT-LFE), thereby decreasing hip angle error.

Anterior hip joint force increases with hip extension, decreased gluteal force, or decreased iliopsoas force

Abnormal or excessive force on the anterior hip joint may cause anterior hip pain, subtle hip instability and a tear of the acetabular labrum. We propose that both the pattern of muscle force and hip joint position can affect the magnitude of anterior joint force and thus possibly lead to excessive force and injury. The purpose of this study was to determine the effect of hip joint position and of weakness of the gluteal and iliopsoas muscles on anterior hip joint force. We used a musculoskeletal model to estimate hip joint forces during simulated prone hip extension and supine hip flexion under four different muscle force conditions and across a range of hip extension and flexion positions. Weakness of specified muscles was simulated by decreasing the modeled maximum force value for the gluteal muscles during hip extension and the iliopsoas muscle during hip flexion. We found that decreased force contribution from the gluteal muscles during hip extension and the iliopsoas muscle during hip flexion resulted in an increase in the anterior hip joint force. The anterior hip joint force was greater when the hip was in extension than when the hip was in flexion. Further studies are warranted to determine if increased utilization of the gluteal muscles during hip extension and of the iliopsoas muscle during hip flexion, and avoidance of hip extension beyond neutral would be beneficial for people with anterior hip pain, subtle hip instability, or an anterior acetabular labral tear.

Stretch reflex modulation during imposed static and dynamic hip movements in standing humans

The purpose of this study was to investigate the effects of hip proprioceptors on soleus stretch reflex excitability in standing humans. A custom-made device to stretch the ankle extensors was mounted on the lower leg portion of a gait orthosis and was used to elicit stretch reflex responses while standing. Six subjects with motor complete spinal cord injury (SCI) and six spinal intact subjects were placed in the orthosis, and stretch reflex responses were elicited when static and/or dynamic hip joint angle changes were imposed. We found that static hip extension significantly enhanced the stretch reflex responses as compared to the neutral position and the hip flexion position only in the SCI group. The EMG magnitude induced by hip extension was 142 +/- 16.6% greater than that induced by the neutral position. When the leg was dynamically swung, the reflex responses also changed with the phase of the hip angle in the SCI group; in particular, the reflex amplitude was enhanced with hip extension and in the transition phase from flexion to extension. Although the magnitude of the changes was less than that in the SCI group, a similar type of modulation was found in the normal group. Given the fact that the persons with SCI had lost the neural connection between higher nervous center and the paralyzed lower limb muscles, the mechanism underlying the present results can be attributed to the peripheral afferent input due to the hip angle changes. We concluded that hip mediated afferent input has a significant influence on the excitability modulation of the soleus stretch reflex pathway. Such neural modulation may play a role in the mechanism responsible for the phase-dependent modulation of the stretch reflex while walking.

HIP DISLOCATION - FOOTBALL

HISTORY - A 9-year-and-6-month-old male football athlete was making a tackle when three opposing players landed on his left leg. He was unsure of his position during the tackle, but experienced immediate and severe left hip pain. He was unable to move his left leg, keeping it in a position of hip and knee flexion. He was taken from the field to the mergency room by EMS. PHYSICAL EXAM - Examination in the emergency room revealed significant left leg pain with the extremity resting in a position of hip flexion, adduction, internal rotation and knee flexion. Pain was localized to the hip. He had no palpable tenderness in the left knee, ankle or foot and no tenderness in his thoracic or lumbar spine. He demonstrated normal sensation through out the extremity and normal motor function distally. DIFFERENTIAL DIAGNOSIS Hip dislocation Hip fracture Pelvic fracture TESTS AND RESULTS EMERGENCY ROOM RADIOGRAPHS Anterior Posterior Pelvis: - skeletally immature individual with dislocation of the left hip. No fractures are seen. Lateral Left Hip: - posterior dislocation of the femoral head with no obvious fracture. CT Scan (Pelvis) - Post Reduction - concentric reduction of left hip. No fracture seen. No fragments in joint. FINAL/WORKING DIAGNOSIS Posterior dislocation of the left hip. TREATMENT IV sedation and closed reduction of the left hip. Post reduction x-rays and CT scan Admitted 23 hrs. for pain control, bedrest, and crutch training. Non weight bearing for 3–6 weeks Gradual return to weight bearing and activities Serial x-rays to evaluate for AVN.

Idiopathic Hip Instability

The painful, snapping hip often presents a diagnostic dilemma having many potential etiologies. An understanding of the precise cause increases the potential for successful treatment. Five patients with no prior history of significant trauma were evaluated, all of whom had longstanding painful snapping in the groin and consistent symptoms of gait disturbance and increased pain in the provocative position of hip flexion, adduction, and internal rotation. Multiple prior tests and procedures had been nondiagnostic. Simple manual longitudinal traction under fluoroscopy showed subluxation with appearance of a vacuum sign in the symptomatic hip, whereas no such finding was observed on the asymptomatic side. This strongly suggests atraumatic hip instability as a previously unrecognized cause of the painful, snapping hip. The easily obtainable diagnostic traction radiograph is described.