Iliofemoral Ligament Research Articles

The predominant insertion of the ischiofemoral ligament is a merging to the iliofemoral ligament as demonstrated on magnetic resonance arthrogram studies.

The capsular ligaments at the hip joint work in synchrony with the acetabulum and femoral head for articular stability. There is a lack of understanding about ischiofemoral ligament (ISFL) anatomy and function. To assess the insertion of the ISFL in non-arthritic adult hips. A retrospective analysis was performed in 72 patients who underwent magnetic resonance arthrogram (MRA) for the assessment of hip pain. The distribution of the ISFL components, the thickness, and the insertion site were assessed by concomitantly using the axial oblique, coronal, and sagittal MRA images. Two insertions of the ISFL anterior to the center of the femoral head were identified in 71 (99%) hips: (i) predominant anterior merging with the iliofemoral ligament as continuation of zona orbicularis, observed in all hips; and (ii) anterolateral junction of femoral neck and greater trochanter. Two ISFL parts (proximal and distal) were identified in 70 (97%) of the 72 studied hips. The proximal part was always thinner (mean 2.6 ± 0.7 mm) and originated from the ischium at the acetabular rim. The distal part was a continuation of the zona orbicularis, and the mean thickness was 6.7 ± 1.6 mm. Both parts merged as they coursed over the superior portion of the femoral head. The predominant insertion of the ischiofemoral ligament is a merging to the iliofemoral ligament anteriorly. Surgical procedures such as hip arthroscopy involving the ISFL will affect the function of the iliofemoral ligament, and vice versa.

Contributions of capsular releases to femoral exposure in total hip arthroplasty via the direct anterior approach

BackgroundIn total hip arthroplasty via the direct anterior approach, appropriate exposure is critical to allow preparation of the femur. The objective of this study was to explore the optimal soft tissue releases needed to allow broaching of the femur through a combination of experimental tests and computer simulations. MethodsFourteen full-body cadaveric specimens were included in this study. Total hip arthroplasty was performed via the direct anterior approach with the femur at 20° adduction and 20°extension. Soft tissue releases were performed sequentially, namely, the transverse iliofemoral ligament, descending iliofemoral ligament, ischio-femoral ligament, conjoint tendon, and obturator externus. After each release, the femur mobility was assessed by applying a 6 Nm external rotation torque and a 120 N distraction force. Subsequently, using specimen-specific models and models of the broach and handle, the broach passage after each release was simulated, and the release that allowed broach passage was analyzed. FindingsThe average external rotation after releasing the transverse and descending iliofemoral ligaments increased by 14.1° ± 6.1° and 13.8° ± 5.3°. With subsequent soft tissue releases, the rotational mobility increased incrementally, though the impact decreased. Impingement between the broach passage and the pelvis was mainly at the anterior superior iliac spine and the anterior inferior iliac spine. The volume of impingement decreased from 4.8 ± 4.5 cm3 after resection of the femoral head to 1.8 ± 1.6 cm3 and 1.2 ± 1.9 cm3 after release of the transverse and descending iliofemoral ligament, respectively. InterpretationWith sequential soft-tissue releases, the femur mobility increased incrementally. However, the number of releases needed for each femur varied extensively between specimens. Most (10/14) femurs became accessible after the release of the ilio-femoral or ischio-femoral ligament.

Poster 187: Describing the Contribution of the Vacuum Effect and Hip Capsule in Restraint to Axial Traction in Patients Undergoing Hip Arthroscopy

Objectives: In recent investigations, there has been increased focus on hip laxity and hip capsular instability, particularly in the setting of hip arthroscopy. The capsule and its internal negative pressure effects have been shown to be major contributors to hip joint stability, however, the relative contributory role of these elements remains unknown. Intraoperatively, improved understanding of hip capsule biomechanics is imperative for optimization of arthroscopic technique to access the central compartment with minimal soft tissue trauma. In turn, this can help reduce the risk of hip instability and maximize patient outcomes. The purpose of this study was to define the stiffness coefficient of the hip capsule and vacuum phenomenon in response to hip axial traction. Our hypothesis was that the vacuum phenomenon would have a greater relative contribution to axial distraction stiffness at mid-range distraction, and that the hip capsule stiffness coefficient would be greater at terminal distraction. Methods: A review of a prospectively collected database of patients undergoing hip arthroscopy was conducted from 1 July 2021 to 31 June 2022. Patients in this database underwent hip arthroscopy for the treatment of femoroacetabular impingement syndrome (FAIS). Inclusion criteria were 1) completion of the study traction protocol and 2) completion of hip joint venting prior to capsulotomy. Exclusion criteria were 1) previous hip surgery and 2) lack of hip distraction at 50 pounds of axial traction. The study traction protocol involved applying axial traction prior to instrumentation (Native State) of the hip using a post-free distraction system. Hips were then vented using a spinal needle and the traction protocol was repeated (Vented State). Traction intervals were 0, 50, and 100 lbs of force. Fluoroscopic images were taken at each traction interval and standardized to preoperative radiographs, which allowed for a calculation of the lateral joint space width at each interval. Overall distraction distance was calculated as the difference between 0 lbs traction and 50 and 100 lbs traction. The stiffness coefficient was calculated as k = traction force interval/distraction distance in both the Native and Vented States. Comparisons using paired-samples t-tests were conducted between the stiffness coefficients of the Native State and Vented State at 50 lbs and at 100 lbs. A p-value of <0.05 was utilized to indicate statistical significance. Results: Twenty-one patients were identified who met inclusion criteria. Mean age was 34.4 ± 13.4 years with 100% female and a mean BMI of 24.2 ± 4.8 points. Mean stiffness coefficient at 50 lbs in the Native State (10.9 ± 3.3) was significantly higher than the Vented State (4.9 ± 0.7, p < 0.001), with similar findings at 100 lbs in the Native State (10.1 ± 1.7) and Vented State (8.7 ± 1.3, p < 0.001). In the Vented State, the stiffness coefficient was significantly greater at 100 lbs (8.7 ± 1.3) than at 50 lbs (4.9 ± 0.7, p < 0.001). Conclusions: Our results provide an objective characterization of the individual contributions of the hip soft tissue restraints and the vacuum phenomenon to hip resistance to axial traction. At 50 pounds of traction, the vacuum effect contributes to ~55% of the axial distraction stiffness (resistance to axial distraction). At 100 pounds of traction force, the vacuum effect contributes only ~14% of the axial distraction stiffness. The resistance of the hip to axial distraction is of substantial clinical significance as minimization of traction force decreases intraoperative soft tissue trauma. This, however, needs to be balanced with obtaining sufficient working space within the hip joint. There is still substantial controversy regarding the biomechanics of the hip and the optimal methods for minimizing traction force related injury (e.g., post-less traction, minimization of traction time, air arthrogram, and joint venting). These data demonstrate that soft tissues have a proportionally greater effect on restraint of the of the hip at terminal distraction (~1 cm distraction), whereas the vacuum effect has a greater influence on mid-range distraction (~0.5 cm distraction). The proposed model for this phenomenon is that the negative pressure and the soft tissue tension work in parallel to restrain the hip joint. The increased influence of the soft tissue tension at end-range distraction may be due to a check rein effect of the soft tissues; once the iliofemoral ligament has been tensioned to its maximum length its stiffness and capacity for transfer of tensile force increases rapidly. In conclusion, at 50 pounds of traction, the vacuum effect contributes to ~55% of the axial distraction stiffness (resistance to axial distraction). At 100 pounds of traction force, the vacuum effect contributes only ~14% of the axial distraction stiffness. These results demonstrate that the vacuum effect is a significant restraint to axial traction applied across the hip at mid-range distraction. Additionally, the hip capsule has a relatively greater contribution to terminal distraction stiffness.

Dysplastic Hips Have Decreased Iliofemoral Ligament Thickness on Coronal Sequences in Magnetic Resonance Imaging: A Matched Cohort Analysis

To characterize hip capsule thickness on advanced imaging in patients with and without hip dysplasia and to also evaluate differences in capsular thickness between patients with borderline and patients with true dysplasia. Patients evaluated by the senior author for concerns of hip pathology from June 2020 to June 2021 were queried and images reviewed to determine dysplasia status by lateral center-edge angle (LCEA) ≤25°. A group of patients without dysplasia was identified and matched for age, sex, and body mass index. Hip capsular thickness was quantified using magnetic resonance imaging. A subanalysis was conducted to compare patients with true dysplasia (LCEA < 20°) with patients with borderline dysplasia (LCEAs between 20° and 25°). The analysis included independent samples t tests, χ2 tests, and multivariable regression. A total of eighty patients were included, with a mean age of 31.8 ± 11.7 years, a mean body mass index of 26.6 ± 6.5 points, and 70% (56) female patients. Patients with dysplasia had a mean LCEA of 19.8 ± 4.3°. Patients with dysplasia had decreased capsular thickness compared with patients without dysplasia (2.75 ± 0.96 mm vs 3.52 ± 1.22 mm, P= .003). Multivariable regression showed decreased capsular thickness associated with decreased LCEAs (β= 2.804, R= 0.432, P < .001) and dysplasia (β= -0.709, R2= 0.056, P= .004). Results of a subanalysis of the dysplastic group examining differences between accepted definitions of borderline dysplasia and true dysplasia showed no significant differences in capsular thickness between the 2 groups (P= .379). Patients with hip dysplasia were found to have thinner iliofemoral ligaments in the coronal plane on magnetic resonance imaging on magnetic resonance imaging. Further investigation is needed to evaluate any potential implications with hip instability, given the thinner hip capsule demonstrated in this study. Level III, retrospective comparative prognostic trial.

Associations Between Hip Pathology, Hip and Groin Pain, and Injuries in Hockey Athletes: A Clinical Commentary.

5.

Contribution of the Medial Iliofemoral Ligament to Hip Stability After Total Hip Arthroplasty Through the Direct Anterior Approach

BackgroundDislocation after total hip arthroplasty (THA) is a primary reason for THA revision. During THA through the direct anterior approach (DAA), the iliofemoral ligament, which provides the main resistance to external rotation (ER) of the hip, is commonly partially transected. We asked: (1) what is the contribution of the medial iliofemoral ligament to resisting ER after DAA THA? and (2) how much resistance to ER can be restored by repairing the ligament? MethodsA fellowship-trained surgeon performed DAA THA on 9 cadaveric specimens. The specimens were computed tomography scanned before and after implantation. Prior to testing, the ER range of motion of each specimen to impingement in neutral and 10° of extension was computationally predicted. Each specimen was tested on a 6-degrees-of-freedom robotic manipulator. The pelvis was placed in neutral and 10° of extension. The femur was externally rotated until it reached the specimen’s impingement target. Total ER torque was recorded with the medial iliofemoral ligament intact, after transecting the ligament, and after repair. Torque at extremes of motion was calculated for each condition. To isolate the contribution of the native ligament, the torque for the transected state was subtracted from both the native and repaired conditions. ResultsThe medial iliofemoral ligament contributed an average of 68% (range, 34 to 87) of the total torque at the extreme of motion in neutral and 80% (58 to 97) in 10⁰ of extension. The repaired ligament contributed 17% (1 to 54) of the total torque at the extreme of motion in neutral and 14% (5 to 38) in 10⁰ of extension, restoring on average 18 to 25% of the native resistance against ER. ConclusionsThe medial iliofemoral ligament was an important contributor to the hip torque at the extreme of motion during ER. Repairing the ligament restored a fraction of its ability to generate torque to resist ER.

Relationship Between Hip Capsular Thickness and Instability After Previous Hip Arthroscopic Surgery: A Matched-Cohort Analysis.

Thinner anterior hip capsules are associated with hip laxity, but there is little known about the impact of capsular thickness on the development of instability after primary hip arthroscopic surgery. To investigate the relationship between hip capsular thickness as measured on preoperative magnetic resonance imaging (MRI) and the development of hip instability after hip arthroscopic surgery for femoroacetabular impingement. Case-control study; Level of evidence, 3. We reviewed revision hip arthroscopic procedures performed between January 1, 2019, and May 1, 2021, at a single institution. Inclusion criteria were preoperative MRI/magnetic resonance arthrography, completion of the study traction protocol, and asymmetric distraction between the hips of ≥3 mm on examination under anesthesia. A comparison group of patients treated for femoroacetabular impingement with primary hip arthroscopic surgery who did not develop capsular instability were matched 1:1 to the patients with instability. Superolateral hip capsular thickness was measured on MRI before index surgery. Analysis was conducted using independent-samples t tests and multivariable linear regression. A total of 44 patients were included, with 22 patients each in the instability and no-instability groups. The mean capsular thickness was lower in the patients with hip instability than in those without (1.9 ± 0.6 vs 3.4 ± 1.1 mm, respectively; P < .001). Decreased capsular thickness was significantly associated with hips with instability versus no-instability (β = -1.468 [95% CI, -2.049 to -0.887]; P < .001). Thinner preoperative hip capsules in the region of the iliofemoral ligament were seen in patients who subsequently underwent revision arthroscopic surgery for hip instability compared to patients who underwent primary hip arthroscopic surgery without subsequent revision. Patients at a higher risk for the development of postoperative hip instability had a superolateral hip capsular thickness of <2 mm.

Association Between Anterior Hip Capsule Thickening and Sagittal Pelvic Alignment Among Patients With Developmental Dysplasia of the Hip.

The pathogenesis and pathology of secondary osteoarthritis (OA) of the hip, which is mainly due to developmental dysplasia of the hip (DDH), in Japan are obscure. There are some reports on the thickening of the hip capsule, but the relationship between the thickness of the hip capsule and the pelvic alignment due to hip deformity is not well known. This research investigated whether the capsular thickness of female DDH patients was related to pelvic alignment. This single-center cross-sectional study included female patients aged 50-79 years (n=13) who had undergone primary total hip arthroplasty (THA) due to secondary hip OA with a background of DDH. The part of the hip capsule including the iliofemoral ligament was resected and measured directly with a digital caliper. The Sharp angle, center-edge (CE) angle, sacral slope (SS), pelvic tilt (PT), pelvic incidence (PI), and lumbar lordosis angle (LLA) were measured with an X-ray image to investigate the relationship between the capsular thickness and the pelvic posture. Pearson's correlation coefficient showed a negative correlation between hip capsular thickness and Sharp angle (r=-0.57, p>0.05). No significant correlation was found between the thickness of the hip capsule and the sagittal X-ray parameters including SS, PT, PI, LLA, and CE angle in the coronal plane. The thickness of the hip capsule is moderately associated with the Sharp angle on the coronal plane. The results of this study suggest that the thickness of the joint capsule does not necessarily relate to the degenerative process among patients with DDH and the process can be complex to apply two-dimensional postural indices for the explanation.

Preserving the medial arm of the iliofemoral ligament in total hip arthroplasty using the anterolateral approach: Surgical outcomes and patient-reported outcome measure with 2 years follow-up

PurposeIliofemoral ligament (ILFL) is a capsular ligament located in the anterosuperior part of the hip joint capsule and contributes to hip joint stability. The purpose of this study was to compare the surgical outcomes of resection versus preservation procedure of the medial arm of the ILFL in total hip arthroplasty (THA) using the anterolateral approach. MethodsPerioperative outcomes, complication, implant placement and patient-reported outcome measures (PROMs) were evaluated in 42 patients in the resection group and 38 patients in the preservation group. As a PROM, the Japanese Orthopaedic Association Hip Disease Evaluation Questionnaire (JHEQ), was administered at 6 months, 1 year and 2 years postoperatively. ResultsThere was no significant difference in perioperative outcomes, complication and implant placement between the two groups. Satisfaction for the hip joint condition (80.6 ​± ​22.4 vs 89.2 ​± ​20.1), JHEQ pain score (21.5 ​± ​4.5 vs 24.1 ​± ​5.2) at 6 months, and JHEQ pain score (21.6 ​± ​5.1 vs 23.5 ​± ​5.5) at 1 year were significantly better in the preservation group than in the resection group. At 2 years postoperatively, no significant difference was found in PROMs between the two groups. ConclusionOur results indicate that preservation of the medial arm of the ILFL in THA improves pain during the first postoperative year without increased complications or disadvantages of implant placement. Preserving the medial arm of the ILFL may be a safe and effective option to improve the early clinical outcomes after THA using the anterolateral approach.

Poster 142: Capsular Repair Demonstrates Similar Restoration of Resistance to Axial Distraction in Interportal and Periportal Capsulotomies: An In Vivo Propensity Matched Cohort Study

Objectives: Hip arthroscopy has become increasingly prevalent in the United States for treating young adult hip disorders. The periportal capsulotomy, in comparison to the interportal capsulotomy, has been proposed as a technique for decreasing post-arthroscopy hip instability; however, the effects of this technique are largely theoretical. The objectives of this study were to compare the intraoperative distraction profiles of hip arthroscopy patients undergoing interportal versus periportal capsulotomies. The authors hypothesized the periportal capsulotomy would demonstrate greater resistance to axial distraction at both 1) the capsulotomy and 2) final capsular repair, when compared to the interportal capsulotomy. Methods: Patients undergoing primary hip arthroscopy by a single surgeon underwent intraoperative axial distraction testing at 25-, 50-, 75-, and 100-pounds force with each axial distraction distance measured by standardized, normalized fluoroscopic evaluation. Demographics, hip radiographic characteristics, and distraction distance measurements were collected on patients undergoing periportal capsulotomy and on a historical control group undergoing an interportal capsulotomy (Figure 1). Propensity matching was conducted using native state distraction, lateral center edge angle, and gender as covariate to achieve balance between groups. Between group comparisons were then conducted across the matched interportal and periportal groups. Student’s T-test for continuous variables and the Fisher exact test for categorical variables. Intragroup comparison was conducted across three capsule states: native, capsulotomy, and repair. Sequential testing of capsular states for each patient was conducted with the paired T-test. Results: Seventy-four interportal capsulotomies and 122 periportal capsulotomies were identified. Propensity matching yielded 74 hips in each group with standard mean differences of &lt;0.03. Demographic and radiographic characteristics were similar between matched cohorts (p &gt; 0.05) (Table 1). Distraction distances were similar between the interportal and periportal groups in both the capsulotomy and repair states (p &gt; 0.05), while the periportal capsulotomy repair demonstrated decreased hip distraction distance when compared to the native state by 1.48mm at 75lbf and 1.54mm at 100lbf (p &lt; 0.001) (Figure 2). Conclusions: The present study demonstrates that periportal capsulotomy and interportal capsulotomy have similar effects on in vivo hip distractibility. An unrepaired interportal capsulotomy led to an increase in hip distraction of 2.71 mm at 100 lbf (p &lt; 0.001) compared to the native state, while an unrepaired periportal capsulotomy led to an increase in hip distraction of 2.44 mm at 100 lbf (p &lt; 0.001). The periportal capsulotomy technique has been discussed as having the unique advantage of not fully disrupting the iliofemoral ligament and therefore potentially not require a repair; however, the results of the present study indicate that it is biomechanically similar to the interportal capsulotomy in the unrepaired state. Although this finding does not definitively establish a need for capsular repair in all cases when utilizing a periportal capsulotomy, if the surgeon wishes to re-establish native biomechanics, repair should be considered. The present study establishes the in vivo, intraoperative biomechanics of the periportal capsulotomy, for which there were previously no available data. Further, this study establishes that although periportal capsulotomy is a minimally disruptive technique, it has a substantial effect on in-vivo, intraoperative hip stability as measured by hip distraction distance as a result of axial traction forces. While this paper is able to address the biomechanics at the time of surgery, this paper cannot make any conclusions about the healing potential of the capsule when comparing an interportal and a periportal capsulotomy. In conclusion, an unrepaired periportal capsulotomy and interportal capsulotomy have a similar effect on increasing hip axial distraction distance intra-operatively. Performing a capsular repair restores intra- operative resistance to axial distraction in both the periportal and interportal capsulotomy. [Table: see text]

Differentiation of strains in the lateral and medial bands of the iliofemoral ligament: A segmental approach.

Iliofemoral ligament strains have been assessed in a circumscribed portion, limiting the information regarding the strains in the proximal, mid and distal portions. The purpose of this study is to describe the longitudinal and transversal strain within the proximal, mid and distal portions of the lateral and medial bands of the iliofemoral ligament. Ten fresh cadaveric specimens were assessed. The iliofemoral ligaments were divided into medial and lateral bands. Hemispherical beads (2.6 mm) were placed on the lateral and medial borders of each band. Four positions were assessed: abduction, extension, internal and external rotations combined with extension. The hemispherical beads were scanned at the end range of motion using a laser scanner. The three-dimensional position of each bead was used to estimate longitudinal and transversal strains. A three-factor ANOVA was used to compare movements, borders, and portions within each ligament for longitudinal strains. A one-way ANOVA was used to compare transversal strains between portions. This technique showed mean reliability (ICC: 2, 1) of 0.90 ± 0.06. The external rotation showed the highest strains in both ligaments (p < 0.05). Abduction showed a significant difference between the lateral and medial borders in both bands (p = 0.001). Eight movement-border combinations showed a significant difference between proximal, medial, and lateral portions (p < 0.005). According to our results, there is a clear effect of portions (proximal, mid and distal) within the ligament and movements. Abduction shows the lowest strains longitudinally but the largest strains transversally. Although we do not know the impact of this phenomenon, future studies should assess the strains following hip arthroscopies. The latter might improve the impact of this procedure on hip biomechanics. Lastly, the iliofemoral ligament should be assessed using a segmental approach rather than as a complete unit.

Changes Over Time in the Strain on the Inferior Iliofemoral Ligament During a Sustained 5-Minute High-Force Long-Axis Distraction Mobilization: A Cadaveric Study

ObjectiveTo analyze the changes over time in the strain on the inferior iliofemoral (IIF) ligament when a constant high-force long-axis distraction mobilization (LADM) was applied over 5 minutes. DesignA cross-sectional laboratory cadaveric study. SettingAnatomy laboratory. ParticipantsThirteen hip joints from 9 fresh-frozen cadavers (mean age, 75.6±7.8 years; N=13). InterventionsHigh-force LADM in open-packed position was sustained for a period of 5 minutes. Main Outcome Measure(s)Strain on IFF ligament was measured over time with a microminiature differential variable reluctance transducer. Strain measurements were taken at every 15 seconds for the first 3 minutes and every 30 seconds for the next 2 minutes. ResultsMajor changes in strain occurred in the first minute of high-force LADM application. The greatest increase in strain on the IFF ligament occurred at the first 15 seconds (7.3±7.2%). At 30 seconds, the increase in strain was 10.1±9.6%, the half of the total increase at the end of the 5-minute high-force LADM (20.2±8.5%). Significant changes in strain measures were shown to occur at 45 seconds of high-force LADM (F=18.11; P<.001). ConclusionsWhen a 5-minute high-force LADM was applied, the major changes in the strain on IIF ligament occurred in the first minute of the mobilization. A high-force LADM mobilization should be sustained at least 45 seconds to produce a significant change in the strain of capsular–ligament tissue.

Reconstruction of soft noncontractile tissue in the derived therizinosaur Nothronychus: The interplay of soft tissue and stress on hindlimb ossification and posture.

Nothronychus graffami was a large therizinosaur from the Upper Cretaceous of North America. Much of the skeleton is well-preserved and relatively undistorted. The synovial capsule, extracapsular, and intracapsular tendons are reconstructed in N. graffami using existing scars and comparison with the hips of extant theropods and models of extinct theropods. The iliofemoral, pubofemoral, and ischiofemoral ligaments are all modeled. Soft tissue, especially the ischiofemoral and pubofemoral ligaments reduced possible protraction/retraction of the femur at the hip while stabilizing the joint. Therefore, most hindlimb movements took place at the knee. Weight-bearing function in Nothronychus was transferred from the supra-acetabular crest to the pubic peduncle and associated labrum at rest. The femur possessed an intermediately angled neck, convergent with titanosaurs. Therefore, some lateral abduction is proposed, requiring a well-developed meniscus at the knee. Such a posture would result in considerable mediolateral stress along the femoral shaft, resulting in increased transverse ossification. The femur is considered somewhat abducted from the midline, especially when maximally pronated, as the preacetabular ala is more extensive than the post-acetabular ala. This trait would probably result in a laterally divergent femur, as in many birds, resulting in a broad-gauge trackway with wider separation between left and right footprints than observed in many theropod trackways. Limb ratios and ossification patterns suggest a slow, waddling gait. A standard digitiform pose is reconstructed as is common for theropods, but a plantigrade stance cannot be firmly rejected.

Hip Capsular Reconstruction With Indirect Head of the Rectus Femoris Tendon

Hip capsulotomy is performed during arthroscopic hip procedures to achieve adequate visualization of the joint and instrument access. The hip capsule, and in particular the iliofemoral ligament, is an important stabilizer of the hip joint, and patients who undergo capsulotomy without subsequent repair may experience hip pain and instability, with increased risk of requiring revision hip arthroscopy. Therefore, restoring watertight closure of the capsule is necessary to restore native biomechanics and achieve desired postoperative outcomes. Although primary repair or plication suffice in most cases, capsule reconstruction may instead be necessary when there is insufficient tissue, often due to capsular insufficiency following index surgery. The purpose of this Technical Note is to describe the authors’ current technique for arthroscopic hip capsular reconstruction using the indirect head of the rectus femoris tendon in the setting of capsular iatrogenic hip instability, as well as its advantages and disadvantages and technical pearls and pitfalls.

Relationships among hip instability, iliofemoral ligament, and pain in patients with developmental dysplasia of the hip

BackgroundTo evaluate the relationships among hip instability, pain, and morphology of the iliofemoral ligament (ILFL) in patients with developmental dysplasia of the hip (DDH) using ultrasonography (US). MethodsWe reviewed 86 patients (109 hips) with DDH (Group D), 40 patients (46 hips) with borderline hip dysplasia (BDDH) (Group B) and 20 patients (23 hips) without hip pain and bony abnormality (control group). Group D was classified into three subgroups—the severe (group SP), moderate (group MP), and none/mild (group NMP) hip pain groups—using the visual analogue scale (VAS). For evaluating hip instability and ILFL morphology, the distance between the anterior edge of the anterior inferior iliac spine (AIIS) and the horizontal line to the femoral head, and ILFL thickness were measured using US. The difference between the distance in the neutral position and Patrick position was calculated and defined as the femoral head translation distance (FTD). ResultsFTD and ILFL thickness in group D were significantly larger than those in the control group and group B (P < 0.05). There was a significant positive correlation between FTD and ILFL thickness in three groups (r = 0.57, P < 0.05; r = 0.55, P < 0.05; r = 0.62, P < 0.05, respectively). FTD and ILFL thickness in group SP were significantly larger than those in group NMP (P < 0.05). FTD and ILFL thickness in group D had significantly negative correlations with the lateral center edge (r = −0.54, P < 0.05; r = −0.40, P < 0.05, respectively) and vertical-center-anterior angle (r = −0.51, P < 0.05; r = −0.43, P < 0.05, respectively). ConclusionsAcetabular bony deficiency, especially in the anterior and lateral region can result in antero-posterior hip instability, leading to thickened ILFL and hip pain, even in patients with BDDH. These findings may facilitate our understanding and treatment of patients with DDH. When hip instability is suspected, hip US examination may help confirm the diagnosis and assist in providing objective clinical diagnostic evidence.

Ilio-femoral ligament strains during the flexion-abduction-external rotation test: A cadaveric study

BackgroundFlexion-abduction-external-rotation (FABER) test is one of the most used tests during the clinical assessment of the hip joint. The limited range of motions reached could be due to iliofemoral ligament tightness, but no study has assessed capsular ligament strain during this test. The main objective of this study is to report strains within the iliofemoral ligament during the FABER test using a segmental approach. Methods9 hips were harvested, and all muscles were removed. Hemispherical markers (∅ 2.6 mm) were glued on the lateral and medial borders of both the medial and lateral iliofemoral bands, separating each border into proximal, mid, and distal portions. The lower limb was placed in a FABER test position. A laser scanner allowed to digitize the 3D surface of the capsule. A Kruskal-Wallis test was performed to assess the effect of ligaments, borders, and portions. FindingsThe lateral band of the iliofemoral ligament showed greater strains (14.6 ± 11.4%) compared to the medial band (−8.7 ± 14.2%) (p < 0.001). The greatest strains were observed in the distal portion of the lateral border of the lateral band (51.1 ± 21.5%). A decrease in strain was observed in the mid-portion of the medial border of the medial iliofemoral ligament (−27.9 ± 8.9%). InterpretationThe FABER test is used to assess pain at the hip. Our results show that the limited range of motion at the hip during this test might be caused by increased strains in the lateral band. These results demonstrate that a limitation of joint range of motion during the FABER could be due to an excessive tension of the lateral band of the iliofemoral ligament.

Puncture Capsulotomy Technique for Hip Arthroscopy: Midterm Functional Outcomes.

The most common surgical approaches in hip arthroscopy are interportal and T-capsulotomy. However, these methods may introduce capsular instability. Puncture capsulotomy preserves capsuloligamentous integrity by avoiding iatrogenic transection of the iliofemoral capsular ligament. To present minimum 2-year functional outcomes for patients who underwent arthroscopic treatment for acetabular labral tears and concomitant femoroacetabular impingement using the puncture capsulotomy technique. Case series; Level of evidence, 4. The authors conducted a retrospective review of prospectively collected data on patients who underwent arthroscopic acetabular labral tear treatment between December 2013 and May 2019. Included were patients aged ≥18 years who underwent hip arthroscopy by a single surgeon and completed a minimum of 2 years of patient-reported outcome measure (PROM) surveys. Intraoperatively, patients underwent hip arthroscopy via puncture capsulotomy to treat labral tears and any concomitant femoroacetabular impingement. Clinical outcome data consisted of PROMs. A total of 163 hips were included; the mean patient follow-up was 30.4 months (range, 24-60 months; 95% CI, 28.5-32.3 months). Patients had a mean age of 37.9 years (range, 36.1-39.6 years), with a mean body mass index of 25.9 (range, 25.2-26.5). There were significant improvements in mean [95% CI] baseline to final follow-up scores for the 33-Item International Hip Outcome Tool (iHOT-33) (39.6 [36.8-42.4] vs 76.1 [72.7-79.6]), Hip Outcome Score-Activities of Daily Living (70.0 [67.0-73.0] vs 89.3 [87.3-91.3]), modified Harris Hip Score (60.1 [57.9-62.4] vs 84.9 [82.5-87.2]), and Hip Outcome Score-Sports Specific Subscale (41.8 [37.9-45.6] vs 75.7 [71.7-79.7]) (P < .001 for all). Additionally, the mean [95% CI] visual analog scale pain scores were noted to significantly improve throughout the duration of the postoperative period (from 6.3 [5.9-6.7] to 2.2 [1.8-2.6]; P < .001). There were no incidences of infection, avascular necrosis of the femoral head, dislocation/instability, or femoral neck fracture. At the 2-year follow-up, 81.0%, 62.0%, and 58.9% of hips achieved previously published clinically meaningful iHOT-33 thresholds for minimally clinically important difference, Patient Acceptable Symptom Score, and substantial clinical benefit, respectively. Puncture capsulotomy demonstrated significantly improved functional and clinically meaningful outcomes at a minimum 2-year follow-up, along with a minimal complication rate.

Lateral T-Capsulotomy with Hip Arthroscopy for Access and Excision of Posterior Intra-Articular Mass

There is a lack of literature regarding arthroscopic access to the posterior peripheral compartment of the hip. Compared with open surgery, arthroscopy offers less-invasive treatment for intra-articular mass excision. Arthroscopic hip mass excision has focused on selective resection of lesions in the central compartment and anterior peripheral compartment due to difficult and previously undescribed posterior access. We introduce a technique for arthroscopic excision of a posterior intra-articular hip mass consistent with pigmented villonodular synovitis, also known as tenosynovial giant cell tumor, using a modified T-capsulotomy based on the lateral aspect of the hip capsule. This modified capsulotomy allows for more posterior and lateral access to the central and peripheral compartments while minimizing violation of the iliofemoral ligament.

Impact of Capsulotomy on Hip Biomechanics during Arthroscopy.

Background and Objectives: Anterior capsulotomy is routinely performed in hip arthroscopy to improve joint visualization; however, this can partly or completely disrupt the stabilizing ligaments of the hip. This study aimed to report the effects of conventional and extensive arthroscopic capsulotomies on hip stability. Materials and Methods: Eight freshly frozen cadaveric pelvises were used in this study. The range of motion and translation were measured and compared among different capsular conditions utilized in hip arthroscopy, with a special interest in the iliofemoral ligament (IFL) and zona orbicularis (ZO). The conditions included intact capsule, interportal capsulotomy, T-capsulotomy, complete IFL disruption, and complete IFL and ZO disruption. Internal rotation at three flexion planes (−10°, 0°, and 30°) and external rotation at six flexion planes (−10°, 0°, 30°, 60°, 90°, and 110°) were measured with corresponding femoral head translation distance at the application of 2.5 Nm torque. Results: As compared to an intact capsule, a significant increase in external rotation was observed after interportal capsulotomy from −10° to 60° and after T-capsulotomy from −10° to 110° flexion. A significant translation was observed only with a T-capsulotomy, which ranged from 1.9 to 2.3 mm across the flexion angles. Compared with conventional interportal capsulotomy, disruption of the entire IFL resulted in a significant increase in external rotation in all flexion planes, and significant translation was accompanied by disruption of the ZO. Conclusions: Interportal capsulotomy can result in an increase in range of motion, and T-capsulotomy can lead to significant translation. Partial or complete tears of the IFL and ZO can result in further external rotation and translation.

Poster 195: Inverse Relationship of Hip Capsular Thickness on Magentic Resonance Imaging and Increased Axial Distraction Under Anesthesia: Further Characterization of Hip Laxity

Objectives:The hip joint derives its stability from several biomechanical and anatomic factors, including the ligaments of the hip capsule. Recent research has implicated the hip capsule in the pathogenesis of hip instability, which is especially important when considering the inherent violation of the hip capsule with arthroscopic procedures. The purpose of this study was to characterize the relationship between quantitative axial hip distraction and capsular thickness on magnetic resonance imaging (MRI). We hypothesized that thinner hip capsules would be associated with increased axial distraction distances at maximal traction force.Methods:A retrospective review of the senior author’s primary hip arthroscopic procedures was conducted from November 2018 to June 2021. Inclusion criteria were 1) diagnosis of FAI, 2) pre-operative MRI, 3) and intra-operative fluoroscopic imaging conducted at 0 and 100 pounds (lbs) of axial distraction. Intra-operative, fluoroscopic images were obtained at the beginning of the procedure prior to any instrumentation at 0 lbs and 100 lbs of axial traction force. Distraction distance was calculated by comparing the difference of the initial joint space to the total joint space at 100 lbs and measured using a picture archiving and communication system (PACS). Hip capsule thickness was measured on pre-operative MRI or MRA imaging. Anterior and posterior capsular thickness was measured in the axial plane, while superior and inferior capsule thickness was measured in the coronal plane. Anterior and superior measurements approximated the iliofemoral ligament, with posterior and inferior measurements approximating the ischiofemoral and pubofemoral ligaments. Three measurements were taken in each region of the hip capsule and averaged to produce an accurate estimate of hip capsule thickness in each region. Statistical analysis was conducted using multiple linear regression and independent samples t-tests with an alpha of <0.05.Results:Eighty patients were included from 121 charts reviewed, with 41 patients being excluded for lack of appropriate preoperative imaging to evaluate joint distraction or capsular thickness. Bivariable regression demonstrated increased distraction associated with female sex (B = -4.303, p <0.001). Axial distraction was also shown to be increased in relation to decreased capsular thickness in the anterior axial (B = -1.291, p < 0.001), superior coronal (B = -1.433, p <0.001), and posterior axial regions (B = -1.293, p = 0.028). Multivariable regression of the hip capsular measurements demonstrated increased axial distraction associated with decreased superior coronal capsular thickness (B = -1.402, p < 0.001). Independent samples t-tests showed females had significantly decreased hip capsular thickness in the superior coronal, anterior axial, and posterior axial regions (p = <0.05).Conclusions:Our results show several significant associations with hip capsular thickness and hip axial distraction. Patients with thinner hip capsules in the anterior axial, posterior axial, and superior coronal regions were found to have increased axial distraction distances at 100 lbs of force. These findings are in line with previous descriptions of the importance of the iliofemoral ligament and hip stability, which was approximated in this study using the anterior axial and superior coronal measurements. While female sex was observed to be associated with increased axial distraction, this may potentially be secondary to females having statistically thinner hip capsules as shown by our findings. This observation provides a more nuanced anatomic explanation for this association that has been previously reported regarding patient sex and hip laxity. Our findings further demonstrate the importance of the hip capsule as it pertains to hip joint stability, providing a quantitative method to evaluate hip capsular thickness and joint distraction. Clinically, these results are important to consider in the evaluation of hip instability and capsular insufficiency.Table 1.Multivariable regression results with axial distraction at 100 1bs of force as the independent variable