The contribution of the ligamentum teres to the hip fluid seal: A biomechanics study.

BACKGROUND: The suction seal of the hip plays an important role in maintaining hip stability; however, the function of the ligamentum teres in maintaining this seal remains poorly understood. This study aimed to evaluate the effectiveness of the hip suction seal in ligamentum teres deficient hips for joint positions occurring during gait. METHODS: Six fresh-frozen human cadaveric hips were dissected and mounted to an Instron materials test system. Each specimen was analyzed for average peak distraction force, stiffness, and total energy during hip displacement. Testing was performed in the native intact ligamentum teres state and the deficient ligamentum teres state. Specimens were examined in 20° of flexion, neutral, and 10° of extension. FINDINGS: In the neutral position, the ligamentum teres deficient state displayed a significant decrease in peak distraction force (mean difference: 33.2 N, p < 0.001), average stiffness (mean difference: 63.7 N/mm, p = 0.016), and total energy (mean difference: 82.3 mJ, p = 0.022) compared to the intact controls. In extension, the deficient state exhibited a significant decrease in peak distraction force (mean difference: 42.8 N, p < 0.001) and total energy (mean difference: 72.9 mJ, p = 0.007). In flexion, the deficient state displayed a significant decrease in peak distraction force relative to contols (mean difference: 7.1 N, p = 0.003). INTERPRETATION: The ligamentum teres plays a significant role in maintaining the suction seal of the hip, with its effect being most prominent when the hip is in neural alignment or in extension. The findings suggest that ligamentum teres deficiency may be a relevant treatment target in the clinical setting.

Editorial Commentary: For Single-Bundle Anterior Cruciate Ligament Reconstruction, Graft Fixation Should Be Performed at a Medium Tension in Full Extension: Multiple Bundle Reconstruction May Require a Different Strategy.

Successful anterior cruciate ligament reconstruction requires a multifaceted approach to replicate normal knee anatomy and biomechanics. Graft tensioning force and the angle at which this tension is applied intraoperatively are factors under the surgeon's control. The literature suggests the best tensioning strategy for single bundle reconstructions is at medium tension in full extension, while tensioning multiple bundles is best done at 20° at lower overall tension. Graft tensioning should be individualized with attention paid to graft choice and fixation. Generally, stiffer grafts are thought to require additional force to create the same amount of lengthening. For example, bone-patellar tendon-bone grafts tend to be stiffer than quadrupled hamstring grafts and the native anterior cruciate ligament. Hamstring grafts also are thought to exhibit greater stress relaxation over time, thus elongating and potentially causing increased laxity over time. Pretensioning may eliminate some postoperative graft creep, typically more of an issue with hamstring grafts.

Hip Arthroscopic Microfracture Augmented With Platelet-Rich Plasma-Infused Micronized Cartilage Allograft Significantly Improves Functional Outcomes.

PURPOSE: To evaluate functional outcomes and survivorship in patients at 1 year after undergoing arthroscopic microfracture augmented with hyaline allograft for symptomatic chondral defects of the hip. METHODS: Consecutive patients with and without prior hip procedures presenting with Outerbridge grade IV chondral lesion of the acetabulum or femoral head were prospectively followed. Patients underwent hip microfracture augmented with hyaline allograft suspended in autologous platelet-rich plasma between October 2016 and April 2018. Extent of cartilage degeneration was quantified using the chondromalacia severity index (CMI). Patient functional scores, including Tegner, Hip Outcome Score-Activities of Daily Living (HOS-ADL), Sport-Specific Subscale (HOS-SSS), modified Harris Hip Score (mHHS), and Nonarthritic Hip Score (NAHS) were collected preoperatively and at minimum 1-year postoperatively. Minimal clinically important difference (MCID) was analyzed. Statistical significance was established at P < .05. Pearson's coefficient analysis was performed to identify preoperative variables correlated with clinical outcomes. RESULTS: Fifty-seven patients (86.4%) had minimum 1-year follow-up and were included in the final analysis, with a mean age and body mass index (BMI) of 38.3 ± 9.1 years and 27.7 ± 4.9 kg/m2, respectively. Comparison of baseline and postoperative score averages demonstrated significant improvements in Tegner scores (3.7 ± 2.9 vs 5.1 ± 2.6; P = .003), HOS-ADL (63.3 ± 16.4 vs 89.1 ± 14.5; P < .001), HOS-SSS (40.8 ± 20.4 vs 79.5 ± 21.6; P < .001), mHHS (61.5 ± 16.2 vs 87.0 ± 17.7; P < .001), and NAHS (56.6 ± 14.9 vs 78.7 ± 18.3; P < .001). The percentage of patients who achieved MCID for HOS-ADL, HOS-SSS, mHHS, and NAHS were 89.8%, 83.0%, 75.6%, and 81.6%, respectively. Overall, 91.8% of patients met the threshold for achieving MCID in at least one outcome score. Of the 57 patients, 5 (8.8%) failed clinically, with 1 (1.8%) undergoing revision surgery and 4 (6.9%) undergoing conversion to total hip arthroplasty. There was a direct correlation between preoperative alpha angle and postoperative HOS-ADL. Femoral chondral lesion size and CMI inversely correlated with postoperative HOS-ADL. CONCLUSIONS: Treatment of hip chondral defects with microfracture and hyaline allograft augmentation demonstrated excellent survivorship and significantly improved patient report outcomes at 1 year. LEVEL OF EVIDENCE: IV, retrospective case series.

The Modified Ellison Technique: A Distally Fixed Iliotibial Band Transfer for Lateral Extra-articular Augmentation of the Knee.

Lateral extra-articular augmentation (LEA) of anterior cruciate ligament reconstructions significantly reduces graft failure rates. Currently, proximally fixed LEA procedures are popular techniques. However, there are concerns about these techniques regarding anterior cruciate ligament tunnel collision, kinematic overconstraint, and increasing lateral-compartment contact forces. These issues are potentially avoided by the modified Ellison procedure, which is a distally fixed LEA technique. This article describes the surgical details of this easily reproducible technique.

Pie-Crusting Capsulotomy Provides Similar Visualization With Increased Repair Stiffness Compared With a T-Capsulotomy: A Biomechanical Study.

PURPOSE: To compare the area of visualization, capsular stiffness, and strength between the pie-crusting capsulotomy technique and the T-capsulotomy technique following repair. METHODS: Eight matched pairs of fresh-frozen cadaveric hips (n = 16) were divided to either T-capsulotomy or pie-crusting capsulotomy followed by subsequent repair. The area of visualization was measured for all capsulotomy states using a digitizing probe. Hips were then distracted along the iliofemoral ligament in the intact, extended capsulotomy, and repair states. Afterwards, specimens were externally rotated to failure. RESULTS: An average force of 250.1 ± 16.1 N was required to distract intact hips to 6 mm. Both extended capsulotomy techniques reduced the force required to distract the hip 6 mm with no statistical difference between the two (T-capsulotomy [T-cap] = 114.3 ± 63.4 N vs pie-capsulotomy [Pie-cap] = 170.1 ± 38.8 N), P = .07. Subsequent repair of the extended capsulotomies demonstrated the pie-crust capsulotomy required significantly greater force to reach 6 mm of distraction than those with a repaired T-capsulotomy (T-cap = 165.04 ± 40.43N vs Pie-cap = 204.43 ± 10.13N), P = .03. There was no significant difference in ultimate torque to failure between the 2 techniques (T-cap = 22.0 ± 7.41 N·m vs Pie-cap = 27.01 ± 11.13 N·m), P = .28. Visualization significantly increased with each extended capsulotomy, with an average increase of 62% (P < .001) and 48% (P < .001) for the pie- and T-capsulotomies, respectively. CONCLUSIONS: The pie-crusting technique maintained similar strength and increased stiffness to the T-capsulotomy following repair while using less suture. Both techniques provided similar visualization. Clinically, the pie-crusting technique provides an alternative to the T-capsulotomy with similar biomechanical and visual outcomes. CLINICAL RELEVANCE: Visualization during hip arthroscopy can be difficult with large cam morphology. Techniques to improve visualization while restoring the native biomechanics of the hip as best as possible are important.

Association Between Radiological Evidence of Kaplan Fiber Injury, Intraoperative Findings, and Pivot-Shift Grade in the Setting of Acute Anterior Cruciate Ligament Injury.

BACKGROUND: Biomechanical studies have suggested that the Kaplan fibers (KFs) of the iliotibial band play a role in controlling anterolateral rotation of the knee. There is a paucity of clinical information on whether injury to the KF in the setting of anterior cruciate ligament (ACL) rupture contributes to increased rotatory laxity of the knee. PURPOSE/HYPOTHESIS: The purpose was to evaluate the association among radiological evidence of KF injury, intraoperative arthroscopic findings, and grade of pivot shift at the time of ACL reconstruction (ACLR). It was hypothesized that KF injury would be associated with increased injury to the lateral compartment of the knee and a higher grade of pivot shift. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: A retrospective magnetic resonance imaging (MRI) analysis was conducted on 267 patients with ACL-injured knees who underwent primary ACLR. Patients who had MRI and surgery within 60 days of injury were included (mean age, 23.6 years); there were 158 (59.2%) male patients. MRI was performed using standard knee protocols, and diagnostic criteria were applied to identify KF injury. Associations were made among MRI findings, intraoperative findings, and grade of pivot shift with the patient examined under anesthesia at the time of ACLR. A comparison was made between patients with and without radiological evidence of KF injury. RESULTS: The prevalence of KF injury was 17.6% (47/267 patients). Arthroscopic evidence of lateral meniscal injury was associated with KF injury (KF intact, 31%; KF injured, 55%; P = .010). The majority of patients in the intact and injured KF groups had a grade 2 pivot shift (75% and 70%, respectively). A minority had grade 3 pivot shift: 5% in the intact group versus 6.4% in the injured group. There was no association between radiological evidence of KF injury and pivot-shift grade (P = .600). CONCLUSION: In acute ACL injury, KF injuries were not very common (17.6%), and the rate of grade 3 pivot shift was low (5.2%). When present, KF injuries were not associated with a higher-grade pivot shift. However, there was an association between KF injury and lateral meniscal tears identified at the time of ACLR. The role of KFS in controlling anterolateral rotatory laxity in the acute ACL injury in the clinical setting may be less evident when compared with the biomechanical setting.

Needle Length Requirement for Glenohumeral Joint Injection Using the Neviaser Approach.

Intra-articular glenohumeral joint injections are commonly performed in the clinical setting for diagnostic and therapeutic purposes. Multiple approaches are described, including the anterior and posterior approaches and the less studied superomedial (Neviaser) approach. The purpose of this study was to determine the length of needle required to enter the shoulder joint via the Neviaser approach by radiography and magnetic resonance imaging (MRI) measurements. Additionally, the authors sought to identify any correlation between needle length and body mass index (BMI). They performed a retrospective review of 101 consecutive patients evaluated by one faculty member at their institution. Inclusion criteria were age older than 50 years, no previous shoulder surgery, no history of acromioclavicular joint injury, and having a true anteroposterior radiograph and MRI within 1 year of each other. Using a digital imaging system, the Neviaser approach needle path was drawn for both images, and the lengths were measured. Correlation coefficients for needle length and BMI were calculated. The images of 58 (57.4%) male patients and 43 (42.6%) female patients were evaluated (average BMI, 31.2 kg/m2). The average needle length measurement was 4.27 cm on radiograph and 3.9 cm on MRI. Correlation coefficients were r=0.36 (P=.0002) using radiographs and r=0.53 (P<.0001) using MRIs. When using the Neviaser approach, there is a moderate positive correlation between BMI and the measured distance between skin and the glenohumeral joint when assessed on MRI, and a weak positive correlation on radiographs. The authors conclude that an injection needle of 2 inches or greater is required to reliably access the shoulder joint, and this length may increase with increasing BMI. [Orthopedics. 2020;43(4):e215-e218.].

Editorial Commentary: Magnetic Resonance Imaging Evaluation of the Anterolateral Complex-Is Seeing Really Believing?

The anatomic and biomechanical role of the anterolateral complex (ALC) of the knee has gained increased interest in recent years. Specifically, a keen focus has been on magnetic resonance imaging (MRI) evaluation of the ALC in the setting of anterior cruciate ligament injury. Although many of these studies are well designed and conducted, they are based on a foundation of controversial gross anatomy and MRI protocols and scanners not typically used in standard practice. Ultimately, there is a lack of correlation between MRI evidence of injury to the ALC and clinical evaluation of anterolateral rotatory laxity. So, do we believe in what we see or believe in what we feel?

Ankle Arthroscopy With Microfracture for Osteochondral Defects of the Talus.

Therapeutic arthroscopy with microfracture leads to fibrocartilaginous repair and is an effective treatment of osteochondral lesions of the talus. A full diagnostic arthroscopy is performed, and then attention is turned to the osteochondral defect. We describe in detail patient positioning, ankle distraction, portal placement, steps of the diagnostic arthroscopy, and the technique of microfracture. We then discuss the special considerations to be taken regarding the use of a distractor, protection of neurovascular structures, and the indications for microfracture.