Accuracy of 3 Clinical Tests to Diagnose Proximal Hamstrings Tears With and Without Sciatic Nerve Involvement in Patients With Posterior Hip Pain.

PURPOSE: To determine the diagnostic accuracy of the active hamstring test at 30° (A-30) and 90° (A-90) of knee flexion, the long stride heel strike (LSHS) test, and combination of the 3 tests for individuals with hamstring tendon tears, with and without sciatic nerve involvement. METHODS: A retrospective review of 564 consecutive clinical records identified 42 subjects with a mean age of 50.31 ± 15 years who underwent a standard physical examination prior to magnetic resonance imaging (MRI) evaluation and diagnostic injection for posterior hip. The physical examination included the A-30, A-90, and LSHS tests. Sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, and diagnostic odds ratio were calculated to determine the diagnostic accuracy of these 3 tests. RESULTS: Forty-two subjects (female = 32 and male = 10) with a mean age of 50.31 years (range 15-77, ± SD 14.52) met the inclusion criteria and were included in the review. Based on MRI and/or injection, 64.28% (27/42) of subjects were diagnosed with hamstring tear. Fourteen (51.85%) presented with sciatic nerve involvement. The sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, and diagnostic odds ratio for each test were as follows: A-30 knee flexion: 0.73, 0.97, 23.43, 0.28, and 84.73; A-90 knee flexion: 0.62, 0.97, 20.00, 0.39, and 51.67; LSHS: 0.55, 0.73, 2.08, 0.61, and 3.44. The most accurate findings were obtained when the results of the A-30 and A-90 were combined, with sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, and diagnostic odds ratio of 0.84, 0.97, 26.86, 0.17, and 161.89, respectively. CONCLUSION: The combination of the active hamstring A-30 and A-90 tests proved to be a highly accurate and valuable tool to diagnose proximal hamstring tendons tears with or without sciatic nerve involvement in subjects presenting with posterior hip pain. LEVEL OF EVIDENCE: Level III, diagnostic study.

The Hip-Spine Effect: A Biomechanical Study of Ischiofemoral Impingement Effect on Lumbar Facet Joints.

PURPOSE: To assess the relation between ischiofemoral impingement (IFI) and lumbar facet joint load during hip extension in cadavers. METHODS: Twelve hips in 6 fresh T1-to-toes cadaveric specimens were tested. A complete pretesting imaging evaluation was performed using computed tomography scan. Cadavers were positioned in lateral decubitus and fixed to a dissection table. Both legs were placed on a frame in a simulated walking position. Through a posterior lumbar spine approach L3-4 and L4-5 facet joints were dissected bilaterally. In addition, through a posterolateral approach to the hip, the space between the ischium and the lesser trochanter was dissected and measured. Ultrasensitive, and previously validated, piezoresistive force sensors were placed in lumbar facet joints of L3-4 and L4-5. Lumbar facet loads during hip extension were measured in native hip conditions and after simulating IFI by performing lesser trochanter osteotomy and lengthening. Four paired t-tests were performed comparing normal and simulated IFI on the L3-L4 and L4-L5 facet joint loads. RESULTS: After simulating IFI, mean absolute differences of facet joint load were 10.8 N (standard error of the mean [SEM] ±4.53, P = .036) for L3-4 at 10° of hip extension, 13.71 N (SEM ±4.53, P = .012) for L3-4 at 20° of hip extension, 11.49 N (SEM ±4.33, P = .024) for L4-5 at 10° of hip extension, and 6.67 N (SEM ±5.43, P = .245) for L4-5 at 20° of hip extension. A statistically significant increase in L3-4 and L4-5 lumbar facet joint loads of 30.81% was found in the IFI state as compared with the native state during terminal hip extension. CONCLUSIONS: Limited terminal hip extension due to simulated IFI significantly increases L3-4 and L4-5 lumbar facet joint load when compared with non-IFI native hips. CLINICAL RELEVANCE: This biomechanical study directly links IFI to increased lumbar facet loads and supports the clinical findings of IFI causing lumbar pathology. Assessing and treating (open or endoscopic) hip disorders that limit extension could have benefit in patients with concomitant lower back symptoms.

Contribution of the Pubofemoral Ligament to Hip Stability: A Biomechanical Study.

PURPOSE: To determine the isolated function of the pubofemoral ligament of the hip capsule and its contribution to hip stability in external/internal rotational motion during flexion greater than 30° and abduction. METHODS: Thirteen hips from 7 fresh-frozen pelvis-to-toe cadavers were skeletonized from the lumbar spine to the distal femur with the capsular ligaments intact. Computed tomographic imaging was performed to ensure no occult pathological state existed, and assess bony anatomy. Specimens were placed on a surgical table in supine position with lower extremities resting on a custom-designed polyvinylchloride frame. Hip internal and external rotation was measured with the hip placed into a combination of the following motions: 30°, 60°, 110° hip flexion and 0°, 20°, 40° abduction. Testing positions were randomized. The pubofemoral ligament was released and measurements were repeated, followed by releasing the ligamentum teres. RESULTS: Analysis of the 2,106 measurements recorded demonstrates the pubofemoral ligament as a main controller of hip internal rotation during hip flexion beyond 30° and abduction. Hip internal rotation was increased up to 438.9% (P < .001) when the pubofemoral ligament was released and 412.9% (P < .001) when both the pubofemoral and teres ligament were released, compared with the native state. CONCLUSIONS: The hypothesis of the pubofemoral ligament as one of the contributing factors of anterior inferior hip stability by controlling external rotation of the hip in flexion beyond 30° and abduction was disproved. The pubofemoral ligament maintains a key function in limiting internal rotation in the position of increasing hip flexion beyond 30° and abduction. This cadaveric study concludes previous attempts at understanding the anatomical and biomechanical function of the capsular ligaments and their role in hip stability. CLINICAL RELEVANCE: The present study contributes to the understanding of hip stability and biomechanical function of the pubofemoral ligament.

Femoral Neck Anteversion and Lesser Trochanteric Retroversion in Patients With Ischiofemoral Impingement: A Case-Control Magnetic Resonance Imaging Study.

PURPOSE: To assess the relationship between the femoral neck version (FNV) and lesser trochanteric version (LTV) in symptomatic patients with ischiofemoral impingement (IFI) as compared with asymptomatic hips. METHODS: The FNV and LTV of patients with symptomatic IFI who underwent magnetic resonance imaging assessment including a standardized femoral version study protocol were compared with those of patients with asymptomatic hips in this retrospective, observational study. Patients with isolated intra-articular pathology, prior hip fracture, and lesser trochanter deformity were excluded. The FNV, LTV, ischiofemoral space, and quadratus femoris space were evaluated on axial magnetic resonance imaging, as well as the angle between the LTV and the FNV. Independent t-tests were used to determine differences between groups. RESULTS: Data from 11 out 15 symptomatic patients and 250 out of 320 asymptomatic patients were analyzed. The mean ischiofemoral space (11.9 v 22.9 mm; P < .001; 95% confidence interval [CI], 6.9 to 15.2) and mean quadratus femoris space (7.2 mm v 14.9 mm; P < .001; 95% CI, 5.4 to 8.6) were significantly smaller in symptomatic patients versus asymptomatic patients. There was no difference in mean LTV between groups (-23.6° v -24.2°; P = .8; 95% CI, -7.5 to 6.4), however, the mean FNV (21.7° v 14.1°; P = .02; 95% CI, -14.2 to -1.1) and the angle between the FNV and LTV on average (45.4° v 38.3°; P = .01; 95% CI, -12.9 to -1.3) were higher in symptomatic than in asymptomatic patients, with statistical significance. CONCLUSIONS: The femoral mean neck anteversion and the mean angle between the FNV and LTV are significantly higher in patients with symptomatic IFI. The mean LTV is not increased in patients with symptomatic ischiofemoral impingement as compared with those patients with asymptomatic hips. LEVEL OF EVIDENCE: Level III, diagnostic study.

Accuracy of 2 Clinical Tests for Ischiofemoral Impingement in Patients With Posterior Hip Pain and Endoscopically Confirmed Diagnosis.

PURPOSE: To establish the accuracy of the long-stride walking (LSW) and ischiofemoral impingement (IFI) tests for diagnosing IFI in patients whose primary symptom is posterior hip pain. METHODS: Confirmed IFI cases and cases in which IFI had been ruled out were identified considering imaging, injections, and endoscopic assessment, combined with pain relief and negative IFI-specific tests after treatment. Demographic data, duration of symptoms, pain location, ischiofemoral space, quadratus femoris space, quadratus femoris edema, surgical findings, and visual analog scale score for pain before and after treatment were computed for all patients included in this study. Sensitivity, specificity, predictive values, likelihood ratios, and diagnostic odds ratios were computed individually for the LSW test and IFI test. RESULTS: Cases from 1,166 consecutive hip operations and charts from 564 consecutive outpatients were retrospectively reviewed to identify patients who underwent injection and/or endoscopic surgery because of posterior hip pain. Thirty individuals (21 women and 9 men) with a mean age of 49.8 years (range, 20 to 76 years; standard deviation, 13.0 years) were included for analysis. Of the 30 patients, 17 (56.6%) were confirmed as positive for IFI and 13 (43.4%) were confirmed as negative for IFI. The IFI test had a sensitivity of 0.82, specificity of 0.85, positive predictive value of 0.88, negative predictive value of 0.79, positive likelihood ratio of 5.35, negative likelihood ratio of 0.21, and diagnostic odds ratio of 25.6. The LSW test had a sensitivity of 0.94, specificity of 0.85, positive predictive value of 0.89, negative predictive value of 0.92, positive likelihood ratio of 6.12, negative likelihood ratio of 0.07, and diagnostic odds ratio of 88.8. CONCLUSIONS: In patients with complaints of posterior hip pain and negative evaluation findings for lumbosacral spine involvement or static/dynamic mechanical axis malalignment, the IFI and LSW tests are highly accurate to help identify those with or without IFI. LEVEL OF EVIDENCE: Level III, diagnostic study.

The effects of hip abduction on sciatic nerve biomechanics during terminal hip flexion.

Terminal hip flexion contributes to increased strain in peripheral nerves at the level of the hip joint. The effects of hip abduction and femoral version on sciatic nerve biomechanics are not well understood. A decrease in sciatic nerve strain will be observed during terminal hip flexion and hip abduction, independent of femoral version. Six un-embalmed human cadavers were utilized. Three Differential Variable Reluctance Transducers (DVRTs) sensors were placed on the sciatic nerve while the leg was flexed to 70° with a combination of - 10°, 0°, 20° and 40° adduction/abduction. DVRT placement included: (i) under piriformis, (ii) immediately distal to the gemelli/obturator, (iii) four centimeters distal to sensor two. A de-rotational osteotomy to decrease femoral version 10° was performed, and sciatic nerve strain was measured by the same procedure. Data were analyzed with three-way analysis of variance and Bonferroni post-hoc analysis to identify differences in the mean values of sciatic nerve strain between native and decreased version state, hip abduction angle and DVRT sensor location. Significant main effects were observed for femoral version (P = 0.04) and DVRT sensor location (P = 0.01). Sciatic nerve strain decreased during terminal hip flexion and abduction in the decreased version state. An 84.23% decrease in sciatic nerve strain was observed during hip abduction from neutral to 40° in the presence of decreased version at terminal hip flexion. The results obtained from this study confirm the role of decreased femoral version and hip abduction at terminal hip flexion to decrease the strain in the sciatic nerve.

Ischiofemoral Impingement and Hamstring Syndrome as Causes of Posterior Hip Pain: Where Do We Go Next?

Recent advances in understanding hip joint anatomy and biomechanics have contributed to improvement of diagnosis and treatment decisions for distal causes of deep gluteal syndrome (DGS). Ischiofemoral impingement and hamstrings syndrome are sources of posterior hip pain that can simulate symptoms of DGS. The combination of a comprehensive history and physical examination with imaging and ancillary testing are critical for diagnosis. Six key physical examination tests are described to differentiate distal versus proximal sources of extrapelvic posterior hip pain. Outcomes depend on patient compliance and the understanding of the entire anatomy, biomechanics, clinical presentation, and open versus endoscopic treatment options.

Is there a relationship between psoas impingement and increased trochanteric retroversion?

The concept of psoas impingement secondary to a tight or inflamed iliopsoas tendon causing impingement of the anterior labrum during hip extension has been suggested. The purpose of this study was to assess the relationship between the lesser trochanteric version (LTV) in symptomatic patients with psoas impingement as compared with asymptomatic hips. The femoral neck version (FNV) and LTV were evaluated on axial magnetic resonance imaging, as well as the angle between LTV and FNV. Data from 12 symptomatic patients and 250 asymptomatic patients were analysed. The mean, range and standard deviations were calculated. Independent t-tests were used to determine differences between groups. The lesser trochanteric retroversion was significantly increased in patients with psoas impingement as compared with asymptomatic hips (-31.1° SD ± 6.5 versus -24.2° ± 11.5, P < 0.05). The FNV (9° ± 8.8 versus 14.1° ± 10.7, P > 0.05) and the angle between FNV and LTV (40.2° ± 9.7 versus 38.3° ± 9.6, P > 0.05) were not significantly different between groups. In conclusion, the lesser trochanteric retroversion is significantly increased in patients with psoas impingement as compared with asymptomatic hips.

Iliopsoas tendon insertion footprint with surgical implications in lesser trochanterplasty for treating ischiofemoral impingement: an anatomic study.

The objective of this study was to describe the footprint location of the iliopsoas tendon on the lesser trochanter to clarify the surgical implications of the lesser trochanterplasty for treating ischiofemoral impingement. Ten non-matched, fresh-frozen, cadaveric hemipelvis specimens (average age, 62.4 years; range, 48-84 years; 7 male and 3 female) were included. Registered measures included bony parameters of the lesser trochanter (lesser trochanteric area, distances from the tip to the base in a coordinate system, height and area) and tendinous iliopsoas footprint descriptions (areas and detailed location). The mean height of the lesser trochanter was 13.1 (SD ± 1.8) mm, with female having a smaller lesser trochanter on average (11.3, SD ± 2.0). A double tendinous footprint was found in 7 (70%) specimens. The average area of the single- and double-footprint was 211.2 mm(2) and 187.9 mm(2), respectively. An anterior cortical area with no tendinous insertion on the anterior aspect of lesser trochanter was present in all specimens and measured 4.9 mm (SD ± 0.6) on average. The mean ratio between the bald anterior wall and the lesser trochanter height was 38% (SD ± 0.05). The iliopsoas tendon footprint is double (psoas and iliacus) in most cases and is located on the anteromedial tip of the lesser trochanter. A bald anterior wall on the bottom of the lesser trochanter indicates that a partial or total lesser trochanterplasty for increasing the ischiofemoral space without detaching partially or entirely the iliopsoas tendon is improbable.

A MRI study of the lesser trochanteric version and its relationship to proximal femoral osseous anatomy.

The purpose of this study is to quantify the lesser trochanteric version and determine the angle and the relationship between lesser trochanter and femoral neck version. Investigate the influence of the lesser trochanter version in the width of ischiofemoral space. Two hundred and fifty asymptomatic hips were evaluated with axial magnetic resonance image. The lesser trochanter version was calculated. The difference between the femoral neck version and the lesser trochanter version formed the angle between each structure. The width of ischiofemoral space was measured and its relationship with the lesser trochanter version was determined. The mean lesser trochanter version was -24° ± 11.5° (range, - 54° to + 17°) with a coefficient variation of 47.45%. The mean femoral neck version measured 14.0° ± 10.8° (range, -16° to 50°), with a coefficient variation of 81.32%. The lesser trochanter/femora neck angle was 38.4° ± 9.6° (range, 8° to 67°), coefficient variation of 30%, with a moderate correlation between the structures (r = 0.63, P < 0.01). The mean ischiofemoral space was 22.9.0 ± 7.0 mm (range, 10.3 to 55 mm), and a weak correlation was found between ischiofemoral space and lesser trochanteric version (r = -0.16, P < 0.05). The lesser trochanteric version showed a high variation with a moderate relationship with the femoral neck version. The lesser trochanteric version does not influence the width of the ischiofemoral space.