Tranexamic Acid in Foot and Ankle Surgery: A Systematic Review and Meta-Analysis.

Introduction: Tranexamic acid (TXA) use has become common in orthopedic surgeries. Despite the growing number of publications related to its use, no recent systematic reviews have been published examining TXA use in foot and ankle surgery. The purpose of this review article is to provide a summary of the current available literature regarding TXA use in foot and ankle surgery and to further the understanding of its safety and efficacy. Methods: This systematic review utilized PubMed, Ovid, CINAHL, Clinical Key, Medline, and Embase, and the search was conducted through December 22, 2022. Key words used in the search included: "tranexamic acid," "TXA," "foot," "ankle," "calcaneal," and "surgery." The outcomes within the studies analyzed included measures of perioperative blood loss (intra-operative blood loss, 24-hour post-operative blood loss, blood loss from hour 24 to hour 48, post-operative hemoglobin (Hgb), and post-operative hematocrit [Hct]), as well as wound complications and vascular events. Meta-regression was included to assess the impact of age on between-study variation. Results: Ten studies met preliminary inclusion criteria. Upon further inspection, eight met full inclusion criteria for the meta-analysis. Despite a growing amount of literature on the topic, there is still a paucity of literature published on TXA use in foot and ankle surgery. Current literature suggests that foot and ankle surgery patients treated with TXA may have reduced 24-hour post-operative blood loss (MD=-183.41 mL, 95% CI=-247.49 to -119.34 mL, p<0.001), increased post-operative hemoglobin (MD=0.71 g/dL, 95% CI=0.11 to 1.31 g/dL, p=0.020) and hematocrit (MD=2.66%, 95% CI=0.07 to 5.24%, p=0.040) when compared to similar patients not receiving TXA. The use of TXA in foot and ankle surgery did not lead to increased thromboembolic complications. Meta-regression indicated no clinically relevant association of age to between-study variation. Conclusions: TXA was found to be a safe treatment that did affect wound healing or infection rates while decreasing perioperative blood loss. Further research should be performed to evaluate the long-term effects of TXA administration on patient outcomes after foot and ankle surgery.

Benefits of a Postoperative Hip Orthosis After Routine Arthroscopy of the Hip: A Retrospective Cohort Study.

Background: No consensus currently exists among orthopaedic surgeons regarding the benefits of hip orthosis after routine hip arthroscopy. Purpose: To compare patient-reported outcome measures (PROMs) and reoperation rates between patients who were braced versus those who were not braced after routine hip arthroscopy. Study Design: Cohort study; Level of evidence, 3. Methods: A retrospective review was conducted of 193 patients who underwent hip arthroscopy for femoroacetabular impingement (FAI) from January 1, 2018, to December 31, 2021, by 2 orthopedic surgeons at a single institution. Patients before July 1, 2019, were immobilized in a hip orthosis after hip arthroscopy (braced group; n = 101), whereas those after July 1, 2019, were not (nonbraced group; n = 92). Baseline PROMs (visual analog scale for pain, modified Harris Hip Score, Single Assessment Numeric Evaluation, and Veterans Rand 12-Item Health Survey [VR-12] Physical Component Summary and Mental Component Summary) were obtained for all patients and were repeated postoperatively at 2 weeks, 4 weeks, 3 months, 6 months, 1 year, and 2 years. The study groups were compared to evaluate differences in PROMs over time and 2-year postoperative reoperation rates. Group comparisons were also stratified by patient sex. Results: There were no significant differences on any PROM between the braced and nonbraced cohorts at any timepoint. There were also no significant group differences in reoperation rates, with 8 braced patients (7.9%) undergoing reoperation and 1 nonbraced patient (2.3%) undergoing reoperation (P = .208). In the sex-stratified analyses, nonbraced male patients had significantly higher VAS pain and lower VR-12 Mental Component Summary scores at 6 months postoperatively compared with braced male patients (P = .043 and .026, respectively). Conclusion: The study findings suggested that the use of an orthosis after routine hip arthroscopy for FAI does not improve patient-reported outcomes or negatively affect the 2-year reoperation rate. Postoperative bracing increases perioperative cost, and by foregoing routine bracing, patients may avoid the morbidity associated with wearing a brace for a prolonged period.

Effect of sacroiliac fusion on gait, standing balance, and pelvic mobility for unilateral sacroiliac joint dysfunction.

Background: Sacroiliac joint fusion (SIF) has been shown to effectively alleviate pain and improve functional deficits associated with sacroiliac joint dysfunction (SIJD). Previous studies have demonstrated significant improvements in gait function, however, none have reported both over-ground walking and quiescent standing, and additionally, none have included analysis of pelvic kinematics which may contain important information regarding pain avoidant compensatory behaviors. The purpose of this study was to identify objective functional differences between symptomatic and asymptomatic sides of unilateral sacroiliac joint dysfunction (SIJD) patients and to demonstrate the effectiveness of unilateral sacroiliac fusion (SIF) to improve gait and balance function compared to matched controls. Methods: Thirteen unilateral SIJD patients were evaluated before and 6 months after SIF and were compared to matched asymptomatic controls. Pain and disability were assessed using visual analog scales and the Oswestry disability index respectively. Over ground walking and standing balance were assessed using 3D joint kinematics and kinetic ground reaction force analyses. Results: Preoperatively, SIJD patients reported high levels of pain and disability and exhibited significant deficits in gait including elevated step width, reduced hip flexion/extension, and elevated pelvic motion as well as elevated center of pressure sway characteristics during standing. After unilateral SIF, patients reported significant reductions in pain and demonstrated significant improvements in gait including normalization of step width between sides and improved hip motion however elevated pelvic obliquity and rotation motion remained. Improvements in standing balance included reduced coronal sway characteristics and normalization of loading symmetry between sides. Conclusion: Unilateral SIF resulted in significant improvements in both gait and balance function among SIJD patients to levels comparable to matched controls, however elevated pelvic motion remained. These findings help inform surgeons on the effectiveness of SIF for unilateral SIJD and provide important information regarding interpretation of functional outcomes.

Balance effort, Cone of Economy, and dynamic compensatory mechanisms in common degenerative spinal pathologies.

BACKGROUND: Changes in balance are common in individuals with spinal disorders and may cause falls. Balance efficiency, is the ability of a person to maintain their center of gravity with minimal neuromuscular energy expenditure, oftentimes referred to as Cone of Economy (CoE). CoE balance is defined by two sets of measures taken from the center of mass (CoM) and head: 1) the range-of-sway (RoS) in the coronal and sagittal planes, and 2) the overall sway distance. This allows spine caregivers to assess the severity of a patient's balance, balance pattern, and dynamic posture and record the changes following surgical intervention. Maintenance of balance requires coordination between the central nervous and musculoskeletal systems. RESEARCH QUESTION: To discern differences in balance effort values between common degenerative spinal pathologies and a healthy control group. METHODS: Three-hundred and forty patients with degenerative spinal pathologies: cervical spondylotic myelopathy (CSM), adult degenerative scoliosis (ADS), sacroiliac dysfunction (SIJD), degenerative lumbar spondylolisthesis (DLS), single-level lumbar degeneration (LD), and failed back syndrome (FBS), and 40 healthy controls were recruited. A functional balance test was performed approximately one week before surgery recorded by 3D video motion capture. RESULTS: Balance effort and compensatory mechanisms were found to be significantly greater in degenerative spinal pathologies patients compared to controls. Head and Center of Mass (CoM) overall sway ranged from 65.22 to 92.78 cm (p < 0.004) and 35.77-53.31 cm (p < 0.001), respectively in degenerative spinal pathologies patients and in comparison to controls (Head: 44.52 cm, CoM: 22.24 cm). Patients with degenerative spinal pathologies presented with greater trunk (1.61-2.98°, p < 0.038), hip (4.25-5.87°, p < 0.049), and knee (4.55-6.09°, p < 0.036) excursion when compared to controls (trunk: 0.95°, hip: 2.97°, and knee: 2.43°). SIGNIFICANCE: The results of this study indicate that patients from a wide variety of degenerative spinal pathologies similarly exhibit markedly diminished balance (and compensatory mechanisms) as indicated by increased sway on a Romberg test and a larger Cone of Economy (CoE) as compared to healthy controls. Balance effort, as measured by overall sway, was found to be approximately double in patients with degenerative spinal pathologies compared to healthy matched controls. Clinicians can compare CoE parameters among symptomatic patients from the different cohorts using the Haddas' CoE classification system to guide their postoperative prognosis.

Reporting and tracking objective functional outcome measures: implementation of a summary report for gait and balance measures.

The aim of this manuscript is to describe knowledge gaps in the literature, future directions, and emerging applications of gait and balance analysis in spine surgery with regard to functional outcomes measurement. Functional outcome measurement has been established as a useful clinical and research investigational tool in musculoskeletal disease. Evidence currently supports its use in the diagnosis, treatment, and outcome measurement of multiple musculoskeletal disease states, including spinal disease, and its usefulness continues to grow as literature develops. Gait and balance analysis has proven to be broadly applicable, but most clinicians remain unfamiliar and untrained in its usage. The logistical and communication barriers are also described with the potential solutions that are on the near horizon of research. This article describes our methodology for improving conveyance of functional outcome measures in spine surgery. Additionally, we provide a case example of an adult patient with spinal deformity who is examined pre and post operatively using our methodology.

Lumbar Decompression and Interbody Fusion Improves Gait Performance, Pain, and Psychosocial Factors of Patients With Degenerative Lumbar Spondylolisthesis.

STUDY DESIGN: Prospective cohort study. OBJECTIVE: Evaluate changes in gait, pain, and psychosocial factors among degenerative lumbar spondylolisthesis (DLS) patients before and 3 months after surgical intervention. METHODS: Forty-four symptomatic DLS patients performed clinical gait analysis 1 week before surgery and 3 months after surgery. Patients performed a series of over-ground gait trials at a self-selected speed. Twenty-two matched asymptomatic controls underwent the same battery of tests. Three-dimensional motion tracking was used to analyze gait kinematics. Patient-reported outcomes, gait range of motion, and spatiotemporal parameters compared before and after lumbar decompression with fusion. RESULTS: Surgical intervention resulted in significant improvements in walking speed (P = .021), stride time (P = .020), step time (P = .014), and single-support time (P = .038). Significant improvements in joint range-of-motion were found for knee (P = .002) and hip flexion (P = .006). Degenerative lumbar spondylolisthesis patients reported significant reductions in pain, disability, and improved psychological perceptions for fear-avoidance of pain and motion (all P < .001). CONCLUSIONS: Surgical treatment of DLS resulted in a faster, more efficient gait in addition to significant reductions in pain, disability, and psychological fear associated with pain and motion. These beneficial changes that we identified early in the postoperative period indicate that patients return to the quality of life they seek early on. Clinical gait analysis provides objective, quantifiable measures of gait parameters that provide new insight into both the preoperative disability associated with DLS and into the early postoperative function of patients during their rehabilitation.

Representative dynamic ranges of spinal alignment during gait in patients with mild and severe adult spinal deformities.

BACKGROUND CONTEXT: Surgical correction strategies for adult spinal deformity (ASD) relies heavily on radiographic alignment goals, however, there is often debate regarding degree of correction and how static alignment translates to physical ability in daily life. Kinematic analysis has the potential to improve the concept of ideal spinal alignment by providing clinically meaningful estimates of dynamic changes in spinal alignment during activities of daily life. PURPOSE: Estimate representative dynamic ranges of spinal alignment during gait among ASD patients using 3D motion tracking; compare dynamic alignment between mild and severe deformity patients and to healthy adults. STUDY DESIGN/SETTING: Retrospective review at a single institution. PATIENT SAMPLE: Fifty-two ASD patients and 46 healthy adults. OUTCOME MEASURES: Radiographic alignment, kinematic spine motion, spatiotemporal gait measures, patient reported outcomes (VAS pain, ODI, SRS-22r). METHODS: Spinal alignment was assessed radiographically and during standing and overground walking tests. Dynamic alignment was initialized by linking radiographic alignment to kinematic alignment during standing and at initial heel contact during gait. Dynamic changes in maximums and minimums during gait were made relative to initial heel contact for each gait cycle. Total range-of-motion (RoM) was measured for both ASD and healthy subjects. Dynamic alignment measures included coronal and sagittal vertical axes (CVA, SVA), T1 pelvic angle (TPA), lumbar lordosis (LL), and pelvic tilt (PT). ASD patient's deformities were classified as either Mild or Severe based on the SRS-Schwab ASD classification. RESULTS: Severe ASD patients had significantly larger dynamic maximum and minimums for SVA, TPA, LL, and PT (all p<.05) compared with Mild ASD patients. ASD patients exhibited little difference in dynamic alignment compared with healthy subjects. Only PT had a significant difference in dynamic RoM compared with healthy (p<.001). CONCLUSIONS: Mild and Severe ASD patients exhibited similar global dynamic alignment measures during gait and had comparable RoM to healthy subjects except with greater PT and reduced spatiotemporal performance which may be key compensatory mechanisms for dynamic stabilization.

Biomechanics of prophylactic tethering for proximal junctional kyphosis: effects of cyclic loading on tether strength and failure properties.

STUDY DESIGN: Biomechanical evaluation of woven polyester tethers. OBJECTIVES: To quantify changes in tether elongation, stiffness, and failure characteristics after cyclic loading. Ligamentous augmentation is gaining interest as a technique to prevent proximal junctional kyphosis (PJK) in adult spinal fusions. There are a lack of data regarding the effects of cyclic loading on polyester tether mechanical properties. Tether stretch may lead to loss of stabilization and increased risk of tether failure. Biomechanical data are needed to determine the effects of cyclic loading on tether integrity. METHODS: Testing was done in two materials: (1) a synthetic cortical bone composite to determine baseline mechanical properties, and (2) nine cadaveric L1 spinous processes. 5 mm woven polyester tethers were looped through 2.5 mm holes drilled in each material. First, five tethers were tested directly to failure in the synthetic bone to establish baseline failure properties. Next, tethers were tested at one of the three cyclic load ranges [5%, 25%, and 50% (n = 5 each) of baseline failure] for 1000 cycles and then loaded to failure. Cadaveric tests were done at the 25% range and compared to synthetic bone tests at the same range. Cadaveric failure tests were classified as either tether failure or spinous process bone failure. RESULTS: Greater cyclic loading range had a significant effect on tether loop elongation, increased stiffness, and decreased ultimate tensile force. Among the cadaveric failure tests, 56% resulted in tether failure and the remaining 44% resulted in bone failure. CONCLUSIONS: Polyester tethers stretch significantly when loaded to physiological ranges. Anticipation of tether stretch may be an important consideration for a tethering strategy to prevent PJK. Improved understanding of tether material properties can provide guidance for the evaluation of clinical outcomes associated with techniques to reduce the risk of PJK caused by ligamentous laxity. LEVEL OF EVIDENCE: Biomechanical study.

Does improved radiographic alignment truly enhance dynamic functional balance?

STUDY DESIGN: Prospective concurrent cohort study. OBJECTIVE: To establish the relationship between radiographic alignment parameters and functional CoE measurements at 1 week before and at 3 months after realignment surgery in ADS patients. Adult degenerative scoliosis (ADS) represents a significant healthcare burden with exceedingly high and increasing prevalence, particularly among the elderly. Radiographic alignment measures and patient-reported outcomes currently serve as the standard means to assess spinal alignment, deformity, and stability. Neurological examinations have served as qualitative measures for indicating muscle strength, motor deficits, and gait abnormalities. Three-dimensional motion analysis is increasingly being used to identify and measure gait and balance instability. Recently, techniques have been established to quantify balance characteristics described by Dubousset as the "cone of economy" (CoE). The relationship between radiographic alignment parameters and CoE balance measures of ADS patients before and after realignment surgery is currently unknown. PATIENT SAMPLE: 29 ADS patients treated with realignment surgery. METHODS: Patients were evaluated at 1 week before realignment surgery and at their 3-month follow-up examination. During each evaluation, patients completed self-reported outcomes (visual analog scales for pain, Oswestry Disability Index, SRS22r) and a functional balance test. Mean changes in dependent measures from before to after surgery were compared using paired t tests. Pearson correlations were used to test for significant correlations between changes in radiographic and CoE measures. RESULTS: Significant improvements were found for all patient-reported outcomes, in several radiographic measures, and in CoE measures. Improvements of scoliosis Cobb angle, coronal pelvic tilt, lumbar lordosis, and thoracic kyphosis showed significant correlations with CoE sway and total distance measures at both the center of mass and center of the head. CONCLUSION: Improved radiographic alignment measures significantly correlated with improved CoE balance measures among ADS patients treated with realignment surgery at their three-month follow-up. These findings indicate that functional balance evaluations when used in conjunction with radiographic measurements, may provide a more robust and improved patient-specific sensitivity for postoperative assessments. CoE balance may represent a new measure of added value for surgical intervention of ADS.

The Gait Deviation Index as an indicator of gait abnormality among degenerative spinal pathologies.

INTRODUCTION: The Gait Deviation Index (GDI) is a composite measure of gait abnormality derived from lower-limb joint range-of-motion which is increasingly being reported for clinical gait analysis among neurologic and orthopedic patients. A GDI score of 100 is representative of healthy individuals and decreasing scores represent a greater abnormality. Preliminary data is needed to help assess the utility of GDI as a measure of compromised gait among spine patients and to provide reference values for commonly treated pathologies. METHODS: GDI scores were obtained from healthy adults and four symptomatic degeneration groups: cervical spondylotic myelopathy (CSM), adult degenerative scoliosis (ADS), and single-level lumbar degeneration (LD). Clinical gait analysis was done using a three-dimensional motion tracking system. Evaluations were done 1 week prior to surgical intervention for degeneration groups. Two-sample t-tests were used to compare degenerative cohorts to healthy controls and for inter-cohort comparisons. Pearson correlations were used to test for significant relationships between GDI and walking speed. RESULTS: Degenerative cohorts all showed significantly lower (worse) GDI scores compared to healthy (all p < 0.001). CSM patients showed the best GDI scores with an average of 90, and LD patients showed the worst GDI scores with an average of 86. Worsening GDI significantly correlated with decreased walking speed among ADS patients. CONCLUSION: Composite metrics like GDI provide a tempting means to summarize nuanced and complex gait characteristics into a single, comparable value among cohorts. The results of this study provide preliminary GDI scores for common degenerative spine pathologies. These slides can be retrieved under Electronic Supplementary Material.

Initial Response of Mature, Experienced Runners to Barefoot Running: Transition to Forefoot Strike.

INTRODUCTION: Forefoot strike has been advocated for many runners because of the relatively lower impact and push-off forces compared to a heel strike. The purpose of this study was to explore the ability of mature (> 30 years old), experienced runners to transition from a heel foot strike to a forefoot strike when first introduced to barefoot running on a treadmill. We hypothesized: 1) mature runners who heel strike while wearing traditional training shoes would persist in heel striking immediately following a switch to barefoot, 2) mean shoe heel-to-toe drop would be significantly greater in runners who persist in heel striking when running barefoot compared to those who transition to a forefoot strike pattern, and 3) there would be a significant decrease in heel striking in the barefoot condition as running speeds increased. METHODS: This was a controlled crossover laboratory study. Thirty-three experienced runners (average 23.4 miles per week) with an average age of 45.6 years were recruited for this study. The participants first ran in their standard running shoes and subsequently barefoot. A motion capture system was utilized to detect and analyze any transition from heel strike to forefoot strike made by study participants. RESULTS: Of the 26 participants who were classified as heel strike runners in their running shoes, 50% (13/26, p = 0.001) transitioned to forefoot strike when changing from running in shoes to running barefoot. CONCLUSIONS: The injuries associated with transition from standard running shoes to barefoot running or minimalist shoes may be influenced by the persistence of heel striking in mature runners. Older experienced runners may have limited ability to transition from heel to forefoot striking when first introduced to barefoot running. Mature runners should be cautious when beginning a minimalist shoe or barefoot running regimen.

Effect of Ultrasound Frequency and Treatment Duration on Antibiotic Elution from Polymethylmethacrylate Bone Cement.

INTRODUCTION: The objective of this study was to evaluate the effect of ultrasound frequency and treatment duration on antibiotic-impregnated polymethylmethacrylate (PMMA) antibiotic elution rates and mechanical strength. METHODS: Two batches of PMMA were prepared: one with five grams of vancomycin powder and one without. Each batch was divided into two frequency groups: kHz and MHz. Each frequency group was divided into two duration groups: two minutes and ten minutes. Elution samples were measured daily using flow injection analysis. After one week of elution, ultrasound treatments were done daily until each group's average concentration fell below those of non-ultrasound control groups. After elution testing, compression testing determined mechanical properties. Paired t-tests were used to compare daily elution amounts to baseline values. Univariate ANOVAs were used to test for effects of both frequency and treatment duration on antibiotic elution amounts and on mechanical properties. RESULTS: All ultrasound treatments resulted in significant increases in antibiotic elution. Frequency and duration had significant effects of increasing antibiotic elution (p < 0.001). The kHz group produced significantly greater antibiotic elution than the MHz group (p < 0.001). The 10-minute duration produced significantly greater antibiotic elution than the two-minute duration (both p < 0.001). Frequency and duration did not have significant effects on yield stress (p = 0.841 and p = 0.179, respectively). Frequency had a significant effect (p = 0.024) on modulus, but duration did not (p = 0.136). CONCLUSIONS: Ultrasound frequency and treatment duration significantly affect antibiotic elution from PMMA which may be helpful for treatment of periprosthetic joint infections during revision arthroplasty.

Biomechanics of Prophylactic Tethering for Proximal Junctional Kyphosis: Characterization of Spinous Process Tether Pretensioning and Pull-Out Force.

STUDY DESIGN: Biomechanical evaluation of cadaver functional spinal units (FSUs). OBJECTIVES: Demonstrate the effect of increasing spinous process (SP) tether pretension on FSU flexion range of motion (ROM), intervertebral disc (IVD) pressure, and SP force. Quantify SP tether pull-out forces and relate them to SP forces generated at maximum flexion. SUMMARY OF BACKGROUND DATA: There has been recent interest in the use of SP tethering for prophylactic treatment of proximal junctional kyphosis (PJK). There is currently no consensus on standard tethering technique and no biomechanical data on the effect of tether pretension. METHODS: Nine T11-T12 FSUs were tested to 5 Nm of flexion-extension bending. A strain gauge was applied at the base of the T11 SP to measure force. Two custom pressure sensors were inserted into the anterior and posterior thirds of the IVD. Motion kinematics were measured by a motion capture system. An untethered test was done to describe baseline behavior. A 5-mm polyester tether was looped through holes drilled at the base of each SP and pretensioned to five different pretensions ranging from 0 to 88 N. Following ROM testing, specimens were dissected into individual vertebra and then SP pull-out testing was done at each level. RESULTS: Increasing pretension significantly reduced flexion ROM, reduced IVD pressures, and increased SP force. All pretensions, including the minimum, significantly reduced flexion ROM. SP pull-out forces were significantly greater than SP forces generated at maximum flexion. CONCLUSIONS: Tether pretension significantly affects segmental FSU biomechanics. Pretension should be considered an integral factor in the overall success of a tethering strategy. Efforts should be made to control and record pretension intraoperatively. LEVEL OF EVIDENCE: Level V, biomechanical study.

Biomechanics of Prophylactic Tethering for Proximal Junctional Kyphosis: Comparison of Posterior Tether Looping Techniques.

STUDY DESIGN: Biomechanical study. OBJECTIVES: Compare effects of four spinous process (SP) tether looping methods on segmental flexion range of motion (ROM), intervertebral disc (IVD) pressures, and peak tether forces. SUMMARY OF BACKGROUND DATA: SP tethering has been gaining interest as a prophylactic technique to prevent PJK caused by ligamentous laxity in ASD corrective surgery. Several SP tether looping methods have been proposed; however, there is no consensus on appropriate technique. No study has investigated the effect of the tether looping method on segmental biomechanics. METHODS: Nine T1-T4 cadaveric motion segments were tested to 5 Nm of flexion-extension. The uppermost instrumented vertebra (UIV) was located at T3 using standard pedicle screws and fusion rods. A crosslink (CL) was placed inferior to the pedicle screws. A 5-mm polyester tether was looped under the CL at UIV and through holes drilled at the base of UIV + 1 and UIV + 2 SPs. Biomechanical measurements included flexion ROM, IVD pressure, and peak tether forces at UIV/UIV + 1 and UIV + 1/UIV + 2. An untethered test was used for baseline values. Tethered tests included one single-level (SL) method and three double-level (DL) methods: common (CM), chained (CH), and figure-8 (F8). RESULTS: SL yielded significant reductions in flexion ROM at UIV/UIV + 1 (p = .001) and in IVD pressure at UIV/UIV + 1 (p = .007). Choice of DL method had a significant effect on flexion ROM at UIV/UIV + 1 (p = .004) but not at UIV + 1/UIV + 2 (p = .14). Choice of DL method also had a significant effect on IVD pressure at UIV/UIV + 1 (p < .001) but not at UIV + 1/UIV + 2 (p = .311). CM produced the greatest reductions in flexion ROM and IVD pressure, with the lowest peak tether forces among the DL methods. CONCLUSION: Tether looping method significantly alters segmental biomechanics. Tethering with the CM method to UIV + 2 allows for reductions in loads acting on the UIV + 1 SP and posterior ligaments. LEVEL OF EVIDENCE: Level V, biomechanical study.

Evaluation of meniscal extrusion with posterior root disruption and repair using ultrasound.

BACKGROUND: Ultrasound techniques have been utilized for detection of discrete meniscus tears and extrusion. Meniscal extrusion is associated with increased contact pressure and decreased contact area contributing to the advancement of knee osteoarthritis. The purpose of this biomechanical study was to detect meniscal extrusion using a clinically available, portable ultrasound device. And further, to show that extent of injury and a weight-bearing state correlate with amount of extrusion. METHODS: A portable, hand-held ultrasound was utilized to image the lateral meniscus in association with (1) an intact posterior root attachment, (2) a 50% cut, (3) a 100% cut, and (4) repaired posterior root attachment. Images were obtained in an unloaded condition, and again under a static, physiologic (70kg) axial load for above injury levels, and again following repair. RESULTS: Significant differences in extrusion were noted between the intact and both the 50% cut (p=0.028) and 100% cut groups (p<0.001) all in the loaded position. No significant difference was found in extrusion between intact state and repaired posterior root in the axially loaded position (p=0.174). Both load (p=0.003) and injury level (p=0.005) had significant effects on the mean extrusion of the lateral meniscus. CONCLUSION: Sectioning of the lateral meniscus posterior root will produce significantly increased lateral extrusion of the meniscus under physiologic loads. Unlike MRI evaluation, weight-bearing ultrasound images allow a functional assessment of meniscus extrusion. Trans-tibial posterior root repair can restore the lateral meniscus position and integrity. CLINICAL RELEVANCE: This weight-bearing ultrasound technique can be an important assessment tool for complete evaluation of meniscus injuries.