Substance-Related Found-Down Compartment Syndrome: A Systematic Review

OBJECTIVE

To characterize the patient population with substance-related found-down extremity compartment syndrome (FDECS) and report on their treatment and outcome.

DATA SOURCE

This systematic review was performed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines. Articles in English language were identified by searching 3 online databases, EMBASE, PubMed Publisher, and Cochrane Central, in September 2019.

STUDY SELECTION

Studies involving substance-related FDECS were included. Exclusion criteria were as follows: patient age <18 years, not original studies, no full text available, technical reports, traumatic acute extremity compartment syndrome, chronic exertional compartment syndrome, and vascular acute extremity compartment syndrome.

DATA EXTRACTION

There were 61 studies included with 166 cases of FDECS. Two investigators screened and extracted data independently according to a standardized template. Disagreements were addressed by an attempt to reach a consensus, and involvement of a third reviewer. Studies were quality assessed with "Quality Assessment tool for Case Series Studies."

DATA SYNTHESIS

Descriptive statistics were reported using Excel.

CONCLUSION

Substance-related FDECS is often occurring in young adults. Data from this review found that most of the patients were already diagnosed with substance use disorders and/or psychiatric disorders. There should be a high index of suspicion of FDECS in patients presenting after prolonged immobilization.

LEVEL OF EVIDENCE

Prognostic Level IV. See Instructions for Authors for a complete description of levels of evidence.

The effect of surgeon-controlled variables on construct stiffness in lateral locked plating of distal femoral fractures

Background

Nonunion following treatment of supracondylar femur fractures with lateral locked plates (LLP) has been reported to be as high as 21 %. Implant related and surgeon-controlled variables have been postulated to contribute to nonunion by modulating fracture-fixation construct stiffness. The purpose of this study is to evaluate the effect of surgeon-controlled factors on stiffness when treating supracondylar femur fractures with LLPs:

Does plate length affect construct stiffness given the same plate material, fracture working length and type of screws?

Does screw type (bicortical locking versus bicortical nonlocking or unicortical locking) and number of screws affect construct stiffness given the same material, fracture working length, and plate length?

Does fracture working length affect construct stiffness given the same plate material, length and type of screws?

Does plate material (titanium versus stainless steel) affect construct stiffness given the same fracture working length, plate length, type and number of screws?

Methods

Mechanical study of simulated supracondylar femur fractures treated with LLPs of varying lengths, screw types, fractureworking lenghts, and plate/screw material. Overall construct stiffness was evaluated using an Instron hydraulic testing apparatus.

Results

Stiffness was 15 % higher comparing 13-hole to the 5-hole plates (995 N/mm849N vs. /mm, p = 0.003). The use of bicortical nonlocking screws decreased overall construct stiffness by 18 % compared to bicortical locking screws (808 N/mm vs. 995 N/mm, p = 0.0001). The type of screw (unicortical locking vs. bicortical locking) and the number of screws in the diaphysis (3 vs. 10) did not appear to significantly influence construct stiffness (p = 0.76, p = 0.24). Similarly, fracture working length (5.4 cm vs. 9.4 cm, p = 0.24), and implant type (titanium vs. stainless steel, p = 0.12) did also not appear to effect stiffness.

Discussion

Using shorter plates and using bicortical nonlocking screws (vs. bicortical locking screws) reduced overall construct stiffness. Using more screws, using unicortical locking screws, increasing fracture working length and varying plate material (titanium vs. stainless steel) does not appear to significantly alter construct stiffness. Surgeons can adjust plate length and screw types to affect overall fracture-fixation construct stiffness; however, the optimal stiffness to promote healing remains unknown.

3D Bioprinted Bacteriostatic Hyperelastic Bone Scaffold for Damage-Specific Bone Regeneration

Current strategies for regeneration of large bone fractures yield limited clinical success mainly due to poor integration and healing. Multidisciplinary approaches in design and development of functional tissue engineered scaffolds are required to overcome these translational challenges. Here, a new generation of hyperelastic bone (HB) implants, loaded with superparamagnetic iron oxide nanoparticles (SPIONs), are 3D bioprinted and their regenerative effect on large non-healing bone fractures is studied. Scaffolds are bioprinted with the geometry that closely correspond to that of the bone defect, using an osteoconductive, highly elastic, surgically friendly bioink mainly composed of hydroxyapatite. Incorporation of SPIONs into HB bioink results in enhanced bacteriostatic properties of bone grafts while exhibiting no cytotoxicity. In vitro culture of mouse embryonic cells and human osteoblast-like cells remain viable and functional up to 14 days on printed HB scaffolds. Implantation of damage-specific bioprinted constructs into a rat model of femoral bone defect demonstrates significant regenerative effect over the 2-week time course. While no infection, immune rejection, or fibrotic encapsulation is observed, HB grafts show rapid integration with host tissue, ossification, and growth of new bone. These results suggest a great translational potential for 3D bioprinted HB scaffolds, laden with functional nanoparticles, for hard tissue engineering applications.

Multivitamins and risk of fragility hip fracture: a systematic review and meta-analysis

PURPOSE

Hip fracture is a severe complication of osteoporosis and is associated with a significant healthcare burden worldwide. This meta-analysis explores the association between combined multivitamin use and hip fracture risk. Our results provide more patient-centered insight into the impact of supplement use on osteoporosis outcomes.

METHODS

We searched three online databases in August 2019 and included studies that reported on multivitamin use in patients with osteoporotic hip fractures. The inclusion criteria were (1) adult patients with osteoporotic hip fractures, (2) availability of full-text articles in English, and (3) at least 1 year of follow-up. No suitable randomized controlled trials could be identified for inclusion in the analysis. The quality of the included studies was assessed using the Newcastle-Ottawa Scale (NOS).

RESULTS

Eight studies containing 80,148 subjects in total were included in this study. Among these, 4237 cases of fragility hip fracture were reported. The average age was 69±5.3 years, and 21% of subjects were male. Multivitamin use was found to be significantly associated with a lower risk of sustaining a fragility hip fracture (OR 0.49, 95%CI: 0.32-0.77). The Begg and Mazumdar test and funnel plot indicated that no significant publication bias was present.

CONCLUSION

Combined multivitamins are amongst the most widely used supplements and are often preferred over single vitamins. Our meta-analysis indicates that multivitamin use is significantly protective against osteoporotic hip fracture. In the future, randomized controlled trials should be performed to establish multivitamins as effective preventative measures for this injury.

3D printing-assisted fabrication of patient-specific antibacterial radial head prosthesis with high periprosthetic bone preservation

We present a novel fabrication and surgical approach for anatomical reconstruction of a fractured radial head using patient-specific radial head prosthesis made of polymethylmethacrylate (PMMA) bone cement. To this end, the use of PMMA bone cement for prosthesis fabrication was initially investigated using computational modeling and experimental methods. The radial head prosthesis was fabricated through casting of PMMA bone cement in silicone mold in the operation room before implantation. To enhance the precision of bony preparation for replacement of the radial head, patient-specific surgical guide for accurate resection of the radial neck with the desired length was developed. Post-surgical clinical examinations revealed biomechanical restoration of elbow function, owing to the use of patient-specific radial head prosthesis and surgical guide. Importantly, follow-up radiographs after a mean follow-up of 18 months revealed bone preservation at the bone-prosthesis interface without any signs of erosion of the capitellum. Taken together, our method demonstrated the safety and efficacy of the PMMA radial head prosthesis in restoring elbow biomechanics. This also provides a very safe and cost-effective method for making various patient-specific prostheses with localized antibacterial delivery and close mechanical properties to native bone for improved periprosthetic bone regeneration.

Comparison of Patellofemoral Kinematics and Stability After Medial Patellofemoral Ligament and Medial Quadriceps Tendon-Femoral Ligament Reconstruction

BACKGROUND

There is a lack of evidence regarding the optimum extensor-sided fixation method for medial patellofemoral ligament (MPFL) reconstruction. There is increased interest in avoiding patellar drilling via soft tissue-only fixation to the distal quadriceps, thus reconstructing the medial quadriceps tendon-femoral ligament (MQTFL). The biomechanical implications of differing extensor-sided fixation constructs remain unknown.

HYPOTHESIS

The null hypothesis was there would be no differences between traditional MPFL reconstruction and MQTFL reconstruction with respect to resistance to lateral translation, patellar position, or patellofemoral contact pressures.

STUDY DESIGN

Controlled laboratory study.

METHODS

Nine adult knee specimens were mounted on a jig that applied static, physiologic loads to the quadriceps tendons. Patellar position and orientation, knee flexion angle, and patellofemoral pressure were recorded at 8 different flexion angles between 0° and 110°. Additionally, a lateral patellar excursion test was conducted wherein a load was applied directly to the patella in the lateral direction with the knee at 30° of flexion and subjected to 2-N quadriceps loads. Testing was conducted under 4 conditions: intact, transected MPFL, MQTFL reconstruction, and MPFL reconstruction. For MQTFL reconstruction, the surgical technique established by Fulkerson was employed. For MPFL reconstruction, a traditional technique was utilized.

RESULTS

The patellar excursion test showed no significant difference between the MQTFL and intact states with respect to lateral translation. MPFL reconstruction led to significantly less lateral translation (P < .05) than all other states. There were no significant differences between MPFL and MQTFL reconstructions with respect to peak patellofemoral contact pressure. MPFL and MQTFL reconstructions both resulted in increased internal rotation of the patella with the knee in full extension.

CONCLUSION

Soft tissue-only extensor-sided fixation to the distal quadriceps (MQTFL) during patella stabilization appears to re-create native stability in this time 0 cadaver model. Fixation to the patella (MPFL) was associated with increased resistance to lateral translation.

CLINICAL RELEVANCE

Evolving anatomic knowledge and concern for patellar fracture has led to increased interest in MQTFL reconstruction. Both MQTFL and MPFL reconstructions restored patellofemoral stability to lateral translation without increasing contact pressures under appropriate graft tensioning, with MQTFL more closely restoring native resistance to lateral translation at the time of surgery.

Medications as a Risk Factor for Fragility Hip Fractures: A Systematic Review and Meta-analysis

Fragility hip fractures and their associated morbidity and mortality pose a global healthcare problem. Several pharmaceutical products have been postulated to alter bone architecture and contribute to fragility hip fractures. We searched four electronic databases from inception to September 2017. Inclusion criteria were the following: (1) adult patients with fragility hip fractures, (2) full text in English, (3) minimum one-year follow-up, and (4) reporting of at least one risk factor. To minimize heterogeneity among the studies, we performed subgroup analyses. Whenever heterogeneity remained significant, we employed random effect meta-analysis for data pooling. Thirty-eight studies were included, containing 1,244,155 subjects and 188,966 cases of fragility hip fractures. Following medications were significantly associated with fragility hip fractures: Antidepressants (OR 2.07, 95% CI 1.98-2.17), antiparkinsonian drugs (OR 2.21, 95% CI 1.15-4.24), antipsychotic drugs (OR 2.0, 95% CI 1.50-2.66), anxiolytic drugs (OR 1.44, 95% CI 1.19-1.75), benzodiazepines (OR 1.84, 95% CI 1.26-2.69), sedatives (OR 1.33, 95% CI 1.14-1.54), systemic corticosteroids (OR 1.65, 95% CI 1.37-1.99), H₂ antagonists (OR 1.21, 95% CI 1.18-1.24), proton pump inhibitors (OR 1.41, 95% CI 1.16-1.71), and thyroid hormone (OR 1.29, 95% CI 1.13-1.47). Hormone replacement therapy with estrogen (HRT) was associated with decreased risk of hip fracture (OR 0.80, 95% CI 0.65-0.98). There are several medications associated with sustaining a fragility hip fracture. Medical interventions should be considered for patients on these medications, including information about osteoporosis and fracture prevention.

Effect of rotator cuff muscle activation on glenohumeral kinematics: A cadaveric study

Healthy shoulder function requires the coordination of the rotator cuff muscles to maintain the humeral head's position in the glenoid. While glenohumeral stability has been studied in various settings, few studies have characterized the effect of dynamic rotator cuff muscle loading on glenohumeral translation during shoulder motion. We hypothesize that dynamic rotator cuff muscle activation decreases joint translation during continuous passive abduction of the humerus in a cadaveric model of scapular plane glenohumeral abduction. The effect of different rotator cuff muscle activity on glenohumeral translation was assessed using a validated shoulder testing system. The Dynamic Load profile is a novel approach, based on musculoskeletal modeling of human subject motion. Passive humeral elevation in the scapular plane was applied via the testing system arm, while the rotator cuff muscles were activated according to the specified force profiles using stepper motors and a proportional control feedback loop. Glenohumeral translation was defined according to the International Society of Biomechanics. The Dynamic load profile minimized superior translation of the humeral head relative to the conventional loading profiles. The total magnitude of translation was not significantly different (0.805) among the loading profiles suggesting that the compressive forces from the rotator cuff primarily alter the direction of humeral head translation, not the magnitude. Rotator cuff muscle loading is an important element of cadaveric shoulder studies that must be considered to accurately simulate glenohumeral motion. A rotator cuff muscle activity profile based on human subject muscle activity reduces superior glenohumeral translation when compared to previous RC loading profiles.

Scapular Dyskinesis: From Basic Science to Ultimate Treatment

Background: This study intends to summarize the causes, clinical examination, and treatments of scapular dyskinesis (SD) and to briefly investigate whether alteration can be managed by a precision rehabilitation protocol planned on the basis of features derived from clinical tests. Methods: We performed a comprehensive search of PubMed, Cochrane, CINAHL and EMBASE databases using various combinations of the keywords “Rotator cuff”, “Scapula”, “Scapular Dyskinesis”, “Shoulder”, “Biomechanics” and “Arthroscopy”. Results: SD incidence is growing in patients with shoulder pathologies, even if it is not a specific injury or directly related to a particular injury. SD can be caused by multiple factors or can be the trigger of shoulder-degenerative pathologies. In both cases, SD results in a protracted scapula with the arm at rest or in motion. Conclusions: A clinical evaluation of altered shoulder kinematics is still complicated. Limitations in observing scapular motion are mainly related to the anatomical position and function of the scapula itself and the absence of a tool for quantitative SD clinical assessment. High-quality clinical trials are needed to establish whether there is a possible correlation between SD patterns and the specific findings of shoulder pathologies with altered scapular kinematics.

Comparison of surgical and non-surgical treatments for 3- and 4-part proximal humerus fractures: A network meta-analysis

INTRODUCTION

Common treatment strategies for proximal humerus fractures include non-surgical treatment, open reduction internal fixation, hemiarthroplasty, and reverse total shoulder arthroplasty. There is currently no consensus regarding the superiority of any one surgical strategy. We used network meta-analysis of randomized controlled trials to determine the most successful treatment for proximal humerus fractures.

METHODS

MEDLINE, EMBASE, Web of Science, and Cochrane Central electronic databases were searched for randomized controlled trials comparing 3- and 4-part proximal humerus fracture treatments. Data extraction included the mean and standard deviation of clinical outcomes (Constant, DASH), adverse events, and additional surgery rates. Standard Mean Difference was used to compare clinical outcome scores, and pooled risk ratios were used to compare adverse events and additional surgeries.

RESULTS

Eight randomized controlled trials were included for network meta-analysis. Non-surgical treatment was associated with a lower rate of additional surgery and adverse events compared to open reduction internal fixation. Reverse total shoulder arthroplasty resulted in fewer adverse events and a better clinical outcome score than hemiarthroplasty. Non-surgical treatment produced similar clinical scores, adverse event rates, and additional surgery rates to hemiarthroplasty and reverse total shoulder arthroplasty.

CONCLUSION

Non-surgical treatment results in fewer complications and additional surgeries compared to open reduction internal fixation. Preliminary data supports reverse total shoulder arthroplasty over hemiarthroplasty, but more evidence is needed to strengthen this conclusion.

Concept of a Radiofrequency Device for Osteopenia/Osteoporosis Screening

Osteoporosis represents a major health problem, resulting in substantial increases in health care costs. There is an unmet need for a cost-effective technique that can measure bone properties without the use of ionizing radiation. The present study reports design, construction, and testing of a safe, and easy to use radiofrequency device to detect osteoporotic bone conditions. The device uses novel on-body antennas contacting the human wrist under an applied, operator-controlled pressure. For the dichotomous diagnostic test, we selected 60 study participants (23-94 years old, 48 female, 12 male) who could be positively differentiated between healthy and osteopenic/osteoporotic states. The band-limited integral of the transmission coefficient averaged for both wrists, multiplied by age, and divided by BMI has been used as an index. For a 100 MHz frequency band centered about 890-920 MHz, the maximum Youden's J index is 81.5%. Both the sensitivity and specificity simultaneously reach 87% given the calibration device threshold tolerance of ±3%. Our approach correlates well with the available DXA measurements and has the potential for screening patients at risk for fragility fractures, given the ease of implementation and low costs associated with both the technique and the equipment. The inclusion of radiofrequency transmission data does add supplementary useful information to the available clinical risk factors.

A243 FACTORS ASSOCIATED WITH POOR QUALITY OF LIFE IN PATIENTS WITH INFLAMMATORY BOWEL DISEASE IN CLINICAL REMISSION: A CROSS-SECTIONAL STUDY

Background

Inflammatory bowel disease (IBD) is associated with a substantial burden on quality of life (QoL). Functional gastrointestinal disorders such as irritable bowel syndrome (IBS) as well as depression and anxiety are more common in patients with IBD as compared with the general population. Although poorer QoL is correlated with IBS, depression and anxiety in individuals with IBD at times of IBD diagnosis and disease activity, it is unclear what, if any, impact these may have on overall quality of life at times of disease remission.

Aims

We aimed to identify factors associated with poor QoL among Canadian patients with IBD in clinical remission.

Methods

We conducted a prospective, cross-sectional study to determine whether fatigue, depression, anxiety and IBS were associated with lower QoL in patients with IBD in clinical remission. We enrolled patients at a single academic tertiary care center with inactive IBD. All eligible patients completed a series of questionnaires that included questions on demographics, disease activity, anxiety, depression, and the presence of irritable bowel syndrome (IBS) symptoms. Stool samples for fecal calprotectin (FC) were also collected to assess for subclinical inflammation. The primary outcome measure was QoL assessed by the short inflammatory bowel disease questionnaire (SIBDQ), with planned subgroup comparisons for fatigue, anxiety, depression and IBS symptoms.

Results

Ninety-three patients were eligible for inclusion in this study. The median SIBDQ scores were lower in patients with anxiety (P&lt;0.001), depression (P=0.004), IBS symptoms (P&lt;0.001), and fatigue (P=0.018).

Conclusions

In this cross-sectional study, we found that anxiety, depression, fatigue, and IBS-like symptoms were all independently associated with lower QoL among patients with inactive IBD. Importantly, subclinical inflammation as defined by a positive fecal calprotectin in the absence of clinical symptoms did not have an adverse effect on QoL. The findings of this study suggest that patients with IBD would likely benefit from screening for depression, anxiety, fatigue and IBS. Further research is warranted to determine if targeted treatment of these conditions, specifically in patients with quiescent IBD would lead to improved outcomes.

Funding Agencies

None

Diagnostic Modalities for Acute Compartment Syndrome of the Extremities: A Systematic Review

Importance

Acute compartment syndrome (ACS) can cause catastrophic tissue damage leading to permanent muscle and nerve loss. Acute compartment syndrome is a clinical diagnosis, with intracompartmental pressure (ICP) used in equivocal cases. There are no reliable diagnostic methods. The clinical evaluation is impossible to standardize, and the threshold for ICP has been known to be unreliable; thus, guidelines for diagnosis can result in overtreatment or delayed diagnosis.

Objective

To present and review the advantages and disadvantages of each diagnostic modality and identify gaps that need to be addressed in the future and to review the most used and appropriate animal and human ACS models.

Evidence Review

We included clinical studies and animal models investigating diagnostic modalities for ACS of the extremities. A MEDLINE and Web of Science search was performed. The protocol for the study was registered on PROSPERO (CRD42017079266). We assessed the quality of the clinical studies with Newcastle-Ottawa scale and reported level of evidence for each article.

Findings

Fifty-one articles were included in this study, reporting on 38 noninvasive and 35 invasive modalities. Near-infrared spectroscopy and direct ICP measurement using a Stryker device were the most common, respectively. Cadaveric studies used saline infusions to create an ACS model. Most studies with human participants included injured patients with acquired ACS or at risk of developing ACS. In healthy human participants, tourniquets formed the most commonly used ACS model. Application of tourniquets and infusion of saline or albumin were the most used ACS models among animal studies.

Conclusions and Relevance

This article reports on the most common as well as many new and modified diagnostic modalities, which can serve as inspiration for future investigations to develop more effective and efficient diagnostic techniques for ACS. Future studies on diagnostic modalities should include the development of tools for continuous assessment of ICP to better identify the earliest alterations suggestive of impending ACS. With the advent of such technologies, it may be possible to develop far less aggressive and more effective approaches for early detection of ACS.

Consideration of medial anatomical structures at risk when placing quadricortical syndesmotic fixation: A cadaveric study

BACKGROUND

Surgical fixation of syndesmotic instability using quadricortical fixation, whether screws or suture-button devices, places structures on the medial side of the tibia at iatrogenic risk. This study aims to radiographically map the anatomic course of structures on the medial aspect of the distal tibia to be able to at-risk zones (ARZs) for syndesmotic fixation.

METHODS

Eighteen fresh-frozen cadaveric ankle specimens were dissected. The saphenous neurovascular bundle (SNVB) and the posterior tibial tendon (PTT) were identified and marked with copper wiring. Standardized and calibrated lateral radiographs of the distal tibia and fibula were analyzed using a grid system consisting of 3 columnar zones from anterior to posterior and five 1-cm rows to chart the anatomic course of the SNVB and the PTT.

RESULTS

The SNVB was located in the more anterior zones (1, 2, or anterior to Zone 1) in 97.3% of specimens. The SNVB traversed from posterior to anterior as it descended proximal to distal. The PTT was found in Zone 3 (most posterior zone) for all specimens. The PTT was noted to pass behind (radiographically overlap) the tibia in 83.3% (15 of 18) of specimens between 1 and 3 cm above the tibiotalar joint.

CONCLUSIONS

Placement of quadricortical syndesmotic fixation places structures on the medial ankle at risk. The SNVB is at considerable risk along the anterior course of the distal tibial while the PTT is only at risk in zone 3 at the distal extent of the tibia.

Post-traumatic elbow stiffness: Pathogenesis and current treatments

Post-traumatic elbow stiffness is a major cause of functional impairment after elbow trauma. A stiff elbow limits patients' ability to position their hand in space for optimal use of their upper extremities, and as such, is a frequent indication for reoperation. This article reviews current concepts on the pathogenesis of post-traumatic elbow stiffness. Current nonoperative treatment options include therapy, bracing, and manipulation under anesthesia, while operative treatment options include arthroscopic and open arthrolysis. The pros and cons of various treatment options are discussed, with a focus on the evidence supporting their use, the expected functional gains, and associated complications. Future directions in post-traumatic elbow stiffness are highlighted.

Predicting factors of muscle necrosis in acute compartment syndrome of the lower extremity

BACKGROUND

Acute physiologic compartment syndrome (ACS) is a disorder of increased intra-compartmental pressure leading to decreased tissue perfusion and muscle necrosis. Tissue ischemia can result in irreversible muscle and nerve injury and requires urgent fasciotomy. The aim of this study was to determine the factors associated with the presence of necrotic muscle in patients undergoing leg fasciotomy.

METHODS

This is a retrospective cohort study of all patients undergoing fasciotomies for ACS of the leg at two level 1 trauma centers from 2000 to 2015. We found 1,028 patients who underwent leg fasciotomies. We excluded ACS at other sites than the leg, the index fasciotomy performed at an outside institution, prophylactic fasciotomy with no clinical signs of ACS, and patients with inadequate medical records. A total of 357 patients were included in the final analysis. We used bivariate analysis to assess which explanatory variables are associated with the main outcome measure, the presence of necrotic muscle at fasciotomy. We used multivariable regression analysis to determine association accounting for any confounding.

RESULTS

Of 357 cases of ACS of the leg, 14.6% of patients presented with an open fracture and 21.3% of patients were multiply injured. Overall, 14.3% of cases had muscle necrosis at the time of fasciotomy. Fifty-nine percent of patients with necrotic muscle required more than 3 debridements. Open fracture was the only statistically significant predictor of muscle necrosis (OR=2.8). Crush injury (OR=3.1) and soft tissue injuries (OR=2.8) were at an increased odds of necrotic muscle, but only marginally significant.

CONCLUSION

ACS is a potentially limb threatening condition often associated with poor outcomes, particularly when the diagnosis is delayed. Patients with open fracture have a three-fold increase in odds of necrotic muscle at the time of fasciotomy.

Tendon lengthening after achilles tendon rupture-passive effects on the ankle joint in a cadaveric pilot study simulating weight bearing

BACKGROUND

In recent years, primary Achilles tendon ruptures have increased due to the aging population's participation in physically demanding activities. These injuries commonly occur during recreational sports and frequently lead to a long-term reduction in activity despite treatment. Non-operative methods of treatment for Achilles tendon ruptures may result in the Achilles healing in a lengthened position compared to the pre-injury state. This study uses a cadaveric model that simulates static weight bearing to explore the effect of a lengthened Achilles tendon on ankle joint load distribution.

METHODS

Five lower limb cadaveric specimens were placed on a custom jig, where a 334 N (75 lb) load was applied at the femoral head, and the foot was supported against a plate to simulate static double-leg stance. A pressure mapping sensor was inserted into the ankle joint. A percutaneous triple hemiresection tendo-Achilles lengthening procedure (Hoke procedure) was performed on each specimen to simulate tendon lengthening after conservative treatment. Contact pressure, peak pressure, and center-of-pressure were measured for native and tendon-lengthened conditions.

RESULTS

Tendon rupture did not significantly alter average contact pressure, peak contact pressures, or center-of-pressure in the ankle joint compared with native tendon.

CONCLUSION

Achilles lengthening does not significantly change contact pressures of the ankle joint in this model . This result suggests that the passive restraint on ankle joint translation imposed by the Achilles tendon is minimal without muscle activation.

Thermoplastic moulding of regenerated silk

Early insights into the unique structure and properties of native silk suggested that β-sheet nanocrystallites in silk would degrade prior to melting when subjected to thermal processing. Since then, canonical approaches for fabricating silk-based materials typically involve solution-derived processing methods, which have inherent limitations with respect to silk protein solubility and stability in solution, and time and cost efficiency. Here we report a thermal processing method for the direct solid-state moulding of regenerated silk into bulk 'parts' or devices with tunable mechanical properties. At elevated temperature and pressure, regenerated amorphous silk nanomaterials with ultralow β-sheet content undergo thermal fusion via molecular rearrangement and self-assembly assisted by bound water to form a robust bulk material that retains biocompatibility, degradability and machinability. This technique reverses presumptions about the limitations of direct thermal processing of silk into a wide range of new material formats and composite materials with tailored properties and functionalities.

Computational modeling of human bone fracture healing affected by different conditions of initial healing stage

Background

Bone healing process includes four phases: inflammatory response, soft callus formation, hard callus development, and remodeling. Mechanobiological models have been used to investigate the role of various mechanical and biological factors on bone healing. However, the effects of initial healing phase, which includes the inflammatory stage, the granulation tissue formation, and the initial callus formation during the first few days post-fracture, are generally neglected in such studies.

Methods

In this study, we developed a finite-element-based model to simulate different levels of diffusion coefficient for mesenchymal stem cell (MSC) migration, Young’s modulus of granulation tissue, callus thickness and interfragmentary gap size to understand the modulatory effects of these initial phase parameters on bone healing.

Results

The results quantified how faster MSC migration, stiffer granulation tissue, thicker callus, and smaller interfragmentary gap enhanced healing to some extent. However, after a certain threshold, a state of saturation was reached for MSC migration rate, granulation tissue stiffness, and callus thickness. Therefore, a parametric study was performed to verify that the callus formed at the initial phase, in agreement with experimental observations, has an ideal range of geometry and material properties to have the most efficient healing time.

Conclusions

Findings from this paper quantified the effects of the initial healing phase on healing outcome to better understand the biological and mechanobiological mechanisms and their utilization in the design and optimization of treatment strategies. It is also demonstrated through a simulation that for fractures, where bone segments are in close proximity, callus development is not required. This finding is consistent with the concepts of primary and secondary bone healing.

Comparative Efficacy and Safety of Nonsurgical Treatment Options for Enthesopathy of the Extensor Carpi Radialis Brevis: A Systematic Review and Meta-analysis of Randomized Placebo-Controlled Trials

BACKGROUND

Numerous treatment options have been proposed for enthesopathy of the extensor carpi radialis brevis (eECRB).

PURPOSE

To (1) compare the efficacy and safety of nonsurgical treatment options for eECRB described in randomized placebo-controlled trials at short-term, midterm, and long-term follow-up and (2) evaluate outcomes in patients receiving placebo.

STUDY DESIGN

Systematic review and meta-analysis.

METHODS

Following PRISMA guidelines, 4 electronic databases were searched for randomized placebo-controlled trials for eECRB. Studies reporting visual analog scale (VAS) for pain scores and/or grip strength were included. Random- or fixed-effects meta-analysis was employed to compare treatments with at least 2 eligible studies using the standardized mean difference and odds ratio. The study protocol was registered at PROSPERO (ID: CRD42018075009).

RESULTS

Thirty-six randomized placebo-controlled trials, evaluating 11 different treatment modalities, with a total of 2746 patients were included. At short-term follow-up, only local corticosteroid injection improved pain; however, it was associated with pain worse than placebo at long-term follow-up. At midterm follow-up, laser therapy and local botulinum toxin injection improved pain. At long-term follow-up, extracorporeal shock wave therapy provided pain relief. With regard to grip strength, only laser therapy showed better outcomes in comparison with placebo. While there was no difference among various treatments in the odds ratio of an adverse event, they all increased adverse events compared with placebo. In placebo-receiving patients, a sharp increase in the percentage of patients reporting mild pain or less was observed from 2% at short-term follow-up to 92% at midterm follow-up.

CONCLUSION

Most patients experienced pain resolution after receiving placebo within 4 weeks of follow-up. At best, all treatments provided only small pain relief while increasing the odds of adverse events. Therefore, if clinicians are inclined to provide a treatment for particular patients, they may consider a pain relief regimen for the first 4 weeks of symptom duration. Patient-specific factors should be considered when deciding on treatment or watchful waiting.

Genetic basis of rotator cuff injury: a systematic review

Background

Rotator cuff disease is a widespread musculoskeletal pathology and a major cause of shoulder pain. Studies on familial predisposition suggest that genetic plays a role in the pathogenesis of rotator cuff disease. Several genes are responsible for rotator cuff disease. The aim of this study was to perform a systematic review on genetic association between rotator cuff disease and genes variations.

Methods

A systematic review of the literature was performed, in accordance with the PRISMA guidelines. PubMed, Medline, CINAHL, Cochrane, Embase and Google Scholar databases were searched comprehensively using the keywords: “Rotator cuff”, “Gene”, “Genetic”, “Predisposition”, “Single-nucleotide polymorphism” and “Genome-wide association”.

Results

8 studies investigating genes variations associated with rotator cuff tears were included in this review. 6 studies were case-control studies on candidate genes and 2 studies were GWASs. A significant association between SNPs and rotator cuff disease was found for DEFB1, FGFR1, FGFR3, ESRRB, FGF10, MMP-1, TNC, FCRL3, SASH1, SAP30BP, rs71404070 located next to cadherin8. Contradictory results were reported for MMP-3.

Conclusion

Further investigations are warranted to identify complete genetic profiles of rotator cuff disease and to clarify the complex interaction between genes, encoded proteins and environment. This may lead to individualized strategies for prevention and treatment of rotator cuff disease.

Level of evidence

Level IV, Systematic Review.

Biomechanical properties of an intramedullary suture anchor fixation compared to tension band wiring in osteoporotic olecranon fractures- A cadaveric study

Introduction

The aim of the study is to compare three different fixation techniques for transverse olecranon repair in cadaveric osteoporotic bone: (1) current recommended AO tension band technique with K-wire fixation; (2) Suture anchor fixation and (3) Polyester suture fixation.

Methods

Evaluated with bone densitometry, 7 osteoporotic human elbow specimens were included in the study. A transverse olecranon fracture was reduced anatomically and were fixated first using a K-wire tension band technique, second using two suture anchors, and third using polyester suture. Static simulations of the kinetics associated with active range of motion (AROM) and push up from a chair exercises were performed with cyclic loading using Instron hydraulic testing apparatus. Fracture displacement was measured using videographic analysis. Failure was defined as 2 mm fracture displacement.

Results

The biomechanical analysis found no statistical difference in displacements between the three fixation methods when testing AROM. In simulated push-up exercises, polyester suture fixation failed after 17 cycles and had significantly higher displacement compared to the other two methods. No difference between the K-Wire fixation versus Suture anchor fixation was observed, p = 0.162.

Conclusion

Suture anchor fixation might be a viable surgical treatment option for osteoporotic transverse elbow fractures in geriatric patients.

Intraarticular injection of relaxin-2 alleviates shoulder arthrofibrosis

Arthrofibrosis is a prevalent condition affecting greater than 5% of the general population and leads to a painful decrease in joint range of motion (ROM) and loss of independence due to pathologic accumulation of periarticular scar tissue. Current treatment options are limited in effectiveness and do not address the underlying cause of the condition: accumulation of fibrotic collagenous tissue. Herein, the naturally occurring peptide hormone relaxin-2 is administered for the treatment of adhesive capsulitis (frozen shoulder) and to restore glenohumeral ROM in shoulder arthrofibrosis. Recombinant human relaxin-2 down-regulates type I collagen and α smooth muscle actin production and increases intracellular cAMP concentration in human fibroblast-like synoviocytes, consistent with a mechanism of extracellular matrix degradation and remodeling. Pharmacokinetic profiling of a bolus administration into the glenohumeral joint space reveals the brief systemic and intraarticular (IA) half-lives of relaxin-2: 0.96 h and 0.62 h, respectively. Furthermore, using an established, immobilization murine model of shoulder arthrofibrosis, multiple IA injections of human relaxin-2 significantly improve ROM, returning it to baseline measurements collected before limb immobilization. This is in contrast to single IA (sIA) or multiple i.v. (mIV) injections of relaxin-2 with which the ROM remains constrained. The histological hallmarks of contracture (e.g., fibrotic adhesions and reduced joint space) are absent in the animals treated with multiple IA injections of relaxin-2 compared with the untreated control and the sIA- and mIV-treated animals. As these findings show, local delivery of relaxin-2 is an innovative treatment of shoulder arthrofibrosis.

The Effect of Gentamycin in the Irrigating Solution to Prevent Joint Infection after Anterior Cruciate Ligament (ACL) Reconstruction

BACKGROUND

Arthroscopic reconstruction of ACL is an effective method to restore knee stability after ACL rupture. Postoperative septic arthritis (SA) is very uncommon while the incidence of serious complications range between 0.14% and 1.8%. Some of the devastating consequences of septic arthritis can encompass hyaline cartilage damage, arthrofibrosis, and in rare cases amputation. The purpose of this study was to evaluate the effect of gentamicin irrigation solutions as a process to restrain septic arthritis following arthroscopic ACL reconstruction.

METHODS

In this retrospective cohort study, 1464 patients who underwent ACL reconstruction with hamstring tendon autograft in our institution over 7 years (February 2008 to January 2015) were included. The patients were divided into two groups based on the type of intra-articular irrigation solution used during the surgery. Patients in Group 1 (Saline) received intra-articular irrigation with normal saline (0.9 % sodium chloride) solution, while those in Group 2 (Gentamycin) received intra-articular irrigation with gentamicin (80 mg/L) added to the normal saline solution. Data about postoperative infection, its course, management, and outcome were obtained from patients' records.

RESULTS

Seven patients developed SA, four of whom were from SALINE group (2.2%) and three from Gentamycin group (0.23%). The incidence rate of SA after arthroscopic ACL reconstruction was significantly lower (P <0.05) when irrigated with gentamicin solution than merely with saline solution.

CONCLUSION

Gentamicin irrigation solution has a preservative and protective effect against SA development following arthroscopic ACL reconstruction. We recommend evaluating this technique as a way in order to depreciate the prevalence of SA after ACL reconstruction.

Active agents, biomaterials, and technologies to improve biolubrication and strengthen soft tissues

Normal functioning of articulating tissues is required for many physiological processes occurring across length scales from the molecular to whole organism. Lubricating biopolymers are present natively on tissue surfaces at various sites of biological articulation, including eyelid, mouth, and synovial joints. The range of operating conditions at these disparate interfaces yields a variety of tribological mechanisms through which compressive and shear forces are dissipated to protect tissues from material wear and fatigue. This review focuses on recent advances in active agents and biomaterials for therapeutic augmentation of friction, lubrication, and wear in disease and injured states. Various small-molecule, biological, and gene delivery therapies are described, as are tribosupplementation with naturally-occurring and synthetic biolubricants and polymer reinforcements. While reintroduction of a diseased tissue's native lubricant received significant attention in the past, recent discoveries and pre-clinical research are capitalizing on concurrent advances in the molecular sciences and bioengineering fields, with an understanding of the underlying tissue structure and physiology, to afford a desired, and potentially patient-specific, tissue mechanical response for restoration of normal function. Small and large molecule drugs targeting recently elucidated pathways as well as synthetic and hybrid natural/synthetic biomaterials for restoring a desired tissue mechanical response are being investigated for treatment of, for example, keratoconjunctivitis sicca, xeroderma, and osteoarthritis.

Rat Model of Adhesive Capsulitis of the Shoulder

This proposal aims to create an in vivo rat model of adhesive capsulitis for researching potential treatment options for this condition and other etiologies of comparable arthrofibrosis. The model includes extra-articular fixation of the shoulder in rats via scapular to humeral suturing, resulting in a secondary contracture without invading the intra-articular space and resulting in decreased rotational ROM and increased joint stiffness. We used 10 Sprague-Dawley rats for the purpose of this study. Baseline ROM measurements were taken before glenohumeral immobilization. The rats were subjected to 8 weeks of immobilization before the fixation sutures were removed and changes in ROM and joint stiffness were evaluated. To evaluate whether immobilization resulted in a significant reduction in ROM, changes in kinematics were calculated. ROM was measured at each time point in the follow-up period and was compared to the baseline internal and external ROM measurements. In order to evaluate the stiffness, joint kinetics were calculated by determining the differences in torque (text and tint ) needed to reach the initial external rotation of 60° and initial internal rotation of 80°. After the removal of the extra-articular suture fixation on follow-up day 0, we found a 63% decrease in total ROM compared to baseline. We observed continuous improvement until week 5 of follow-up, with the progress slowing down around a 19% restriction. On week 8 of follow-up, there was still an 18% restriction of ROM. Additionally, on follow-up day 0, we found the torque increased by 13.3 Nmm when compared to baseline. On week 8, the total torque was measured to be 1.4 ± 0.2 Nmm higher than initial measurements. This work introduces a rat model of shoulder adhesive capsulitis with lasting reduced ROM and increased stiffness.

Effects of dietary omega-3 fatty acids on bones of healthy mice

BACKGROUND & AIMS

Altering the lipid component in diets may affect the incidence of metabolic bone disease in patients dependent on parenteral nutrition. Consumption of polyunsaturated fatty acids (PUFA) can impact bone health by modulating calcium metabolism, prostaglandin synthesis, lipid oxidation, osteoblast formation, and osteoclastogenesis. The aim of this study was to evaluate the dietary effects of PUFA on murine bone health.

METHODS

Three-weeks-old male (n = 30) and female (n = 30) C57BL/6J mice were randomized into one of three dietary groups. The diets differed only in fat composition: soybean oil (SOY), rich in ω-6 PUFA; docosahexaenoic acid alone (DHA), an ω-3 PUFA; and DHA with arachidonic acid, an ω-6 PUFA, at a 20:1 ratio (DHA/ARA). After 9 weeks of dietary treatment, femurs were harvested for micro-computed tomographic analysis and mechanical testing via 3-point bending. Separate mice from each group were used solely for serial blood draws for measurement of biomarkers of bone formation and resorption.

RESULTS

At the microstructural level, although some parameters in cortical bone reached differences that were statistically significant in female mice, these were too small to be considered biologically relevant. Similarly, trabecular bone parameters in male mice were statistically different in some dietary groups, although the biological interpretation of such subtle changes translate into a lack of effect in favor of any of the experimental diets. No differences were noted at the mechanical level and in blood-based biomarkers of bone metabolism across dietary groups within gender.

CONCLUSIONS

Subtle differences were noted at the bones' microstructural level, however these are likely the result of random effects that do not translate into changes that are biologically relevant. Similarly, differences were not seen at the mechanical level, nor were they reflected in blood-based biomarkers of bone metabolism. Altogether, dietary consumption of PUFA do not seem to affect bone structure or metabolism in a healthy model of growing mice.

Hyperflexion and Femoral Interference Screw Insertion in ACL Reconstruction

Background:

In anatomic anterior cruciate ligament (ACL) reconstructions produced with flexible reamers and no knee hyperflexion, it is unknown whether knee hyperflexion is necessary for femoral interference screw insertion.

Purpose:

To compare femoral screw-graft divergence in anatomic ACL reconstructions with endoscopic interference screws placed without knee hyperflexion and with the use of flexible versus rigid screwdrivers.

Study Design:

Controlled laboratory study.

Methods:

Ten matched pairs of cadaveric knees had bone-tendon-bone graft ACL reconstructions with anatomic femoral tunnels. The knees were flexed to 90°. Femoral interference screws (7 × 20 mm) were placed in pairs of knees: in 1 knee with a flexible screwdriver and in the opposite knee with a rigid screwdriver. Graft-screw divergence was imaged with computed tomography scans and tested with cyclic and static biomechanical tests.

Results:

The mean screw-graft divergence was 12.07° ± 4.04° with the rigid screwdriver and 10.68° ± 3.23° with the flexible screwdriver (P = .35). The cyclic tests with screws placed by a rigid screwdriver had a mean increase in displacement of 0.56 ± 0.20 mm. For screws placed with the flexible screwdriver, the mean increase in displacement was 0.58 ± 0.32 mm (P = .66). Yield load was 393.3 ± 95.1 N for screws placed by a rigid screwdriver and 408.2 ± 119.0 N for screws inserted with the flexible screwdriver (P = .78). Maximum load was 523.1 ± 88.7 N for screws placed by a rigid screwdriver and 467.1 ± 107.3 N for screws inserted with the flexible screwdriver (P = .09).

Conclusion:

With either a rigid or a flexible screwdriver, there were no significant effects on screw divergence or fixation strength.

Clinical Relevance:

Knees can be kept at 90° during endoscopic femoral interference screw insertion. The use of a traditional rigid or flexible screwdriver will not affect screw-graft divergence or fixation strength.

Pressure Distribution in the Ankle and Subtalar Joint With Routine and Oversized Foot Orthoses

BACKGROUND

Foot orthoses are used to treat many disorders that affect the lower limb. These assistive devices have the potential to alter the forces, load distribution, and orientation within various joints in the foot and ankle. This study attempts to quantify the effects of orthoses on the intra-articular force distribution of the ankle and subtalar joint using a cadaveric testing jig to simulate weight bearing.

METHODS

Five lower-limb cadaveric specimens were placed on a custom jig, where a 334-N (75-lb) load was applied at the femoral head, and the foot was supported against a plate to simulate double-leg stance. Pressure-mapping sensors were inserted into the ankle and subtalar joint. Mean pressure, peak pressure, contact area, and center of force were measured in both the ankle and subtalar joints for barefoot and 2 medial foot orthosis conditions. The 2 orthosis conditions were performed using (1) a 1.5-cm-height wedge to simulate normal orthoses and (2) a 3-cm-height wedge to simulate oversized orthoses.

RESULTS

The contact area experienced in the subtalar joint significantly decreased during 3-cm orthotic posting of the medial arch, but neither orthosis had a significant effect on the spatial mean pressure or peak pressure experienced in either joint.

CONCLUSION

The use of an oversized orthosis could lead to a decrease in the contact area and alterations in the distribution of pressure within the subtalar joint.

CLINICAL RELEVANCE

The use of inappropriate orthoses could negatively impact the force distribution in the lower limb.

Risk Factors and Pooled Rate of Prolonged Opioid Use Following Trauma or Surgery: A Systematic Review and Meta-(Regression) Analysis

BACKGROUND

Prolonged use of opioids initiated for surgical or trauma-related pain management has become a global problem. While several factors have been reported to increase the risk of prolonged opioid use, there is considerable inconsistency regarding their significance or effect size. Therefore, we aimed to pool the effects of risk factors for prolonged opioid use following trauma or surgery and to assess the rate and temporal trend of prolonged opioid use in different settings.

METHODS

Following PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines, we searched Embase, PubMed, Web of Science, EBM (Evidence-Based Medicine) Reviews - Cochrane Database of Systematic Reviews, and ClinicalTrials.gov from inception to August 28, 2017, without language restriction. Observational studies reporting risk factors for, or the rate of, prolonged opioid use among adult patients following surgery or trauma with a minimum of 1 month of follow-up were included. Study and patient characteristics, risk factors, and the rate of prolonged opioid use were synthesized.

RESULTS

Thirty-seven studies with 1,969,953 patients were included; 4.3% (95% confidence interval [CI] = 2.3% to 8.2%) of patients continued opioid use after trauma or surgery. Prior opioid use (number needed to harm [NNH] = 3, odds ratio [OR] = 11.04 [95% CI = 9.39 to 12.97]), history of back pain (NNH = 23, OR = 2.10 [95% CI = 2.00 to 2.20]), longer hospital stay (NNH = 25, OR = 2.03 [95% CI = 1.03 to 4.02]), and depression (NNH = 40, OR = 1.62 [95% CI = 1.49 to 1.77]) showed some of the largest effects on prolonged opioid use (p < 0.001 for all but hospital stay [p = 0.042]). The rate of prolonged opioid use was higher in trauma (16.3% [95% CI = 13.6% to 22.5%]; p < 0.001) and in the Workers' Compensation setting (24.6% [95% CI = 2.0% to 84.5%]; p = 0.003) than in other subject enrollment settings. The temporal trend was not significant for studies performed in the U.S. (p = 0.07) while a significant temporal trend was observed for studies performed outside of the U.S. (p = 0.014).

CONCLUSIONS

To our knowledge, this is the first meta-analysis reporting the pooled effect of risk factors that place patients at an increased chance for prolonged opioid use. Understanding the pooled effect of risk factors and their respective NNH values can aid patients and physicians in developing effective and individualized pain-management strategies with a lower risk of prolonged opioid use.

LEVEL OF EVIDENCE

Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Effect of Achilles tendon lengthening on ankle and subtalar joint orientation and load distribution utilizing a novel cadaveric model to simulate weight bearing

Category:

Basic Sciences/Biologics

Introduction/Purpose:

Ankle arthroplasties are increasingly performed to address ankle arthritis. Patients with long standing ankle arthritis often present with an associated achilles tendon contracture. An open or percutaneous lengthening of the Achilles is commonly performed at the same time as the ankle arthroplasty to improve range of motion. Current ankle arthroplasty implants include mobile bearing and fixed bearing systems. Lengthening the achilles tendon improves dorsiflexion, however the effect of the lengthening on the ankle and subtalar joint is not well documented in the literature. Using a novel system to simulate weight bearing in a cadaveric model, we evaluated achilles tendon lengthening and its effect on ankle and subtalar joint orientation and load distribution. This may have potential implications to polyethylene implant longevity in total ankle arthroplasties.

Methods:

Five fresh frozen lower limb cadaveric specimens without known skeletal condition were used. The femoral head was potted with PMMA and TekScan pressure sensors were inserted into the ankle and subtalar joint. The specimens were placed on a custom jig, which allowed for load cell modulated loading of the leg; 75 lb load (half body weight)(4) was applied at the femoral head while the foot was supported against a fixed plate keeping the ankle in neutral position. Mean pressure (MP), peak pressure (PP), contact area (CA), and center of force (COF) were measured in both joints under two conditions; baseline (BASE), and following Achilles tendon release (TENDON) to simulate lengthening. Each condition was tested three times per specimen; the results were averaged per specimen and used for final analysis. Displacement of COF was calculated relative to its location at baseline.

Results:

The Mean Pressure (MP), Peak Pressure (PP) and Contact Area (CA) did not show a statistical difference in the ankle and subtalar joints between baseline (BASE) and TENDON (Achilles tendon release) conditions. (Table 1). Further, the displacement of the COF from the BASE to TENDON was 0.5 mm. In our model, the contracture of the muscle was not fully simulated. Further hindfoot kinetic studies with active achilles contracture may demonstrate a difference in contact forces in the ankle and subtalar joint as compared to normal.

Conclusion:

Ankle arthroplasty is becoming an effective treatment option for ankle joint arthritis. Our novel study demonstrates that Achilles tendon lengthening did not change the mean pressure, peak pressure, contact area center of force in the ankle and subtalar joint. This model provides validation for further studies evaluating tendon release and contact pressure changes in a cadaver with an implanted fixed bearing versus mobile bearing total ankle prosthesis. Difference in polyethylene wear may effect the longevity of ankle replacements. This study will provide clinicians additional information when evaluating the benefit/risks associated with lengthening the Achilles tendon for ankle arthroplasty patients.

Different References for Valgus Cut Angle in Total Knee Arthroplasty

BACKGROUND

The valgus cut angle (VCA) of the distal femur in Total Knee Arthroplasty (TKA) is measured preoperatively on three-joint alignment radiographs. The anatomical axis of the femur can be described as the anatomical axis of the full length of the femur or as the anatomical axis of the distal half of the femur, which may result in different angles in some cases. During TKA, the anatomical axis of the femur is determined by intramedullary femoral guides, which may follow the distal half or near full anatomical axis, based on the length of the femoral guide. The aim of this study was to compare using the anatomical axis of the full length of the femur versus the anatomical axis of the distal half of the femur for measuring VCA, in normal and varus aligned femurs. We hypothesized that the VCA would be different based upon these two definitions of the anatomical axis of the femur.

METHODS

Full-length weight bearing radiographs were used to determine three-joint alignment in normal aligned (Lateral Distal Femoral Angle; LDFA = 87º ± 2º) and varus aligned (LDFA >89º) femurs. Full-length anatomical axis-mechanical axis angle (angle 1) and distal half anatomical axis-mechanical axis angle (angle 2) were measured in all subjects by two independent orthopedic surgeons using a DICOM viewer software (PACS). Angles 1 and 2 were compared in normal and varus aligned subjects to determine whether there was a significant difference.

RESULTS

Ninety-seven consecutive subjects with normally aligned femurs and 97 consecutive subjects with varus aligned femurs were included in this study. In normally aligned femurs, the mean value of angle 1 was 5.05° ± 0.76° and for angle 2 was 3.62° ± 1.19°, which were statistically different (P= 0.0001). In varus aligned femurs, the mean value of angle 1 was 5.42° ± 0.85° and for angle 2 was 4.23° ± 1.27°, which were also statistically different (P= 0.0047).

CONCLUSION

The two different methods of outlining the anatomical axis of the femur lead to different results in both normal and varus-aligned femurs. This should be considered in determination of the valgus cut angle on pre-operative radiographs and be adjusted according to the length of the intramedullary guide.

A Computer Model Assessment of the Effect of Hindfoot Alignment on Mechanical Axis Deviation and Ankle Fractures

Category:

Basic Sciences/Biologics

Introduction/Purpose:

Conventional mechanical axis is calculated from the center of the femoral head to the center of the ankle. Mechanical axis deviation of the lower limb can be associated with a pes planus hindfoot. Malalignment of the lower limb has been shown to increase progression of osteoarthritis of the knee and ankle and decrease joint arthroplasty longevity. Clinically, a pes planus hindfoot has also been seen with patients who present with a stress fracture of the lateral malleolus. This biomechanical study aims to utilize computer modeling to evaluate the hypothesis that altered force transmission on the lateral malleolus with resultant stress fractures in a pes planus model is attributable to mechanical axis deviation.

Methods:

A free-body diagram of the fibula in single leg stance was generated by modeling the fibula as a uniform cylinder. It includes the axially applied load and a single evertor muscle force as an eccentric load applied to the mid-diaphysis . Previously derived relationships between body weight (BW = 667 N, 150lbs) and a) normal axial fibula load (BW*0.17) and b) muscle force (BW*0.25) were used. Fibula length (286.5 mm) and diameter (8 mm) were derived from anthropological data. Mechanical axis deviation in pes planus was simulated in two manners: 1) increased (2 and 3 times normal) axial fibula load and 2) increased evertor muscle force. The compressive stress along the length of the bone was determined through static analysis and the total applied load was compared to theoretical Euler buckling load.

Results:

Increasing the load on the fibula, either by increasing the axial load (Figure 1A) or the muscle load (Figure 1B), increases the maximum compressive stress below the lateral muscle origins, namely the section between the distal tibiofibular ligaments and the evertor muscles. The compressive stress for both cases was less than the compressive yield stress of cortical bone (200 MPa) and cancellous bone (100 MPa) even as the force was increased to the critical buckling value. This model serves as a first attempt to relate the spatial distribution of stress in the fibula with muscle force, axial load, and compressive stress in light of distal fibular fractures associated with pes planus.

Conclusion:

The importance of lower extremity mechanical axis deviation is well established in the progression of arthritis in the knee and ankle. The role of the mechanical axis in the predisposition of stress fractures around the ankle has not been evaluated in the literature. This biomechanical study represents the first attempt to understand how deviation of the mechanical axis can result in stress fractures of the lateral malleolus. Future studies including a finite element analysis will provide further information and the results of these studies may alter how clinicians treat patients with stress fractures of the fibula.

Bone Remodeling under Vibration: A Computational Model of Bone Remodeling Incorporating the Modal Behavior of Bone

Developing precise computational models of bone remodeling can lead to more successful types of orthopedic treatments and deeper understanding of the phenomenon. Empirical evidence has shown that bone adaptation to mechanical loading is frequency dependent and the modal behavior of bone under vibration can play a significant role in remodeling process, particularly in the resonance region. The objective of this study is to develop a bone remodeling algorithm that takes into account the effects of bone vibrational behavior. An extended/modified model is presented based on conventional FE remodeling models. Frequency domain analysis is used to introduce appropriate correction coefficients to incorporate the effect of bone's frequency response into the model. The method is implemented on a bovine bone with known modal/vibration characteristics. The rate and locations of new bone formation depend on the loading frequency and are consistently correlated with the bone modal behavior. The proposed method can successfully integrate the bone vibration conditions and characteristics with the remodeling process. The results obtained support experimental observations in the literature.

Bilateral Arm-Abduction Shoulder Radiography to Determine the Involvement of the Scapulothoracic Motion in Frozen Shoulder

BACKGROUND

We hypothesize that there is no difference in the motion of the scapula with respect to the thoracic wall (scapulothoracic interface) between the affected versus non-affected shoulder on 0° and 90° standard arm abduction radiography.

METHODS

We enrolled 30 patients with the diagnosis of unilateral frozen shoulder after ruling out of other pathologies. Bilateral standard shoulder radiography was done in two position of 0° and 90° of arm abduction. Non-affected side was used as a control group.

RESULTS

The mean scapulothoracic angle of the affected side was significantly larger than the non-affected side in both 0° and 90°of abduction in spite that the scapulohumeral angles were comparable in 0°, indicating potential alteration in scapular positioning.

CONCLUSION

Scapulothoracic motion and position can be affected in frozen shoulder along with other areas. All treatment modalities should be applied to this area as well if substantial difference was detected between the two sides.

Rehabilitation following meniscal repair: a systematic review

Objective

To review existing biomechanical and clinical evidence regarding postoperative weight-bearing and range of motion restrictions for patients following meniscal repair surgery.

Methods and data sources

Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guideline, we searched MEDLINE using following search strategy: ((((“Weight-Bearing/physiology”[Mesh]) OR “Range of Motion, Articular”[Mesh]) OR “Rehabilitation”[Mesh])) AND (“Menisci, Tibial”[Mesh]). Additional articles were derived from previous reviews. Eligible studies were published in English and reported a rehabilitation protocol following meniscal repair on human. We summarised rehabilitation protocols and patients’ outcome among original studies.

Results

Seventeen clinical studies were included in this systematic review. There was wide variation in rehabilitation protocols among clinical studies. Biomechanical evidence from small cadaveric studies suggests that higher degrees of knee flexion and weight-bearing may be safe following meniscal repair and may not compromise the repair. An accelerated protocol with immediate weight-bearing at tolerance and early motion to non-weight-bearing with immobilising up to 6 weeks postoperatively is reported. Accelerated rehabilitation protocols are not associated with higher failure rates following meniscal repair.

Conclusions

There is a lack of consensus regarding the optimal postoperative protocol following meniscal repair. Small clinical studies support rehabilitation protocols that allow early motion. Additional studies are needed to better clarify the interplay between tear type, repair method and optimal rehabilitation protocol.

Anatomical axes of the proximal and distal halves of the femur in a normally aligned healthy population: implications for surgery

BACKGROUND

The anatomical axis of the femur is crucial for determining the correct alignment in corrective osteotomies of the knee, total knee arthroplasty (TKA), and retrograde and antegrade femoral intramedullary nailing (IMN). The aim of this study was to propose the concept of different anatomical axes for the proximal and distal parts of the femur; compare these axes in normally aligned subjects and also to propose the clinical application of these axes.

METHODS

In this cross-sectional study, the horizontal distances between the anatomical axis of the proximal and distal halves of the femur and the center of the intercondylar notch were measured in 100 normally aligned femurs using standard full length alignment view X-rays.

RESULTS

The average age was 34.44 ± 11.14 years. The average distance from the proximal anatomical axis to the center of the intercondylar notch was 6.68 ± 5.23 mm. The proximal anatomical axis of femur passed lateral to the center of the intercondylar notch in 12 cases (12%), medial in 84 cases (84%) and exactly central in 4 cases (4%). The average distance from the distal anatomical axis to the center of the intercondylar notch was 3.63 ± 2.09 mm. The distal anatomical axis of the femur passed medially to the center of the intercondylar notch in 82 cases (82%) and exactly central in 18 cases (18%). There was a significant difference between the anatomical axis of the proximal and distal parts of the femur in reference to the center of intercondylar notch (P value < 0.05), supporting the hypothesis that anatomical axes of the proximal and distal halves of the femur are different in the coronal plane.

CONCLUSIONS

While surgeons are aware that the anatomical axis of the distal part of the femur is different than the anatomical axis of the proximal part in patients with femoral deformities, we have shown that these axes are also different in the normally aligned healthy people due to the anatomy of the femur in coronal plane. Also the normal ranges provided here can be used as a reference for the alignment guide entry point in TKA and antegrade and retrograde intramedullary femoral nailing.

Comparison of adverse events and postoperative mobilization following knee extensor mechanism rupture repair: A systematic review and network meta-analysis

BACKGROUND

Extensor mechanism rupture (EMR) of the knee is a rare but potentially debilitating injury that often occurs due to trauma. While a wide variety of surgical treatments have been reported, there is currently no consensus on the most successful treatment method. The timing of post-operative joint mobilization is also critical for successful recovery after EMR repair. Despite the traditional method of complete immobilization for 6 weeks, there is an increasing trend towards early post-operative knee mobilization. The purpose of this network meta-analysis was to compare adverse event rates and function outcomes between repair methods and between post-operative mobilization protocols.

METHODS

MEDLINE, EMBASE, Web of Science, and Cochrane Central electronic databases were searched in August 2016 for observational studies involving repair of acute, traumatic EMRs. Data extraction included functional outcomes, adverse events, and additional surgeries. Cohort studies that were used in functional outcome analysis were assessed for risk of bias by the Newcastle-Ottawa Quality Assessment Scale (NOS).

RESULTS

Twenty-three studies (709 patients) were included for adverse event analysis. There were no significant differences in adverse event or additional surgery rates between EMR repair methods However, early mobilization produced significantly higher adverse event rates (p=0.02) and total event rates (p<0.001) than late mobilization, but the difference in additional surgery rates was not significant (p=0.06). Six studies (85 patients) were included for functional outcome analysis. There were no significant differences in thigh girth atrophy or muscle strength compared to the contralateral leg between patients treated with transosseous drill holes and simple end-to-end sutures.

CONCLUSIONS

We performed the first network meta-analysis to date comparing treatment of EMRs. Our results support the current body of knowledge that there is no single superior repair method. Although there is an increasing trend towards early or immediate post-operative knee mobilization, we found that early mobilization is associated with significantly higher adverse event and total event rates compared to fixed immobilization for a minimum of 6 weeks, implicating an increased financial burden and decreased quality of life associated with early post-operative mobilization.

Overtightening of the Syndesmosis Revisited and the Effect of Syndesmotic Malreduction on Ankle Dorsiflexion

Category:

Ankle, Trauma

Introduction/Purpose:

Ankle syndesmotic injuries are a significant source of morbidity and require anatomic reduction to optimize outcomes. Although a previous study concluded that maximal dorsiflexion during syndesmotic fixation was not required, methodologic weaknesses existed and several studies have demonstrated improved ankle dorsiflexion after removal of syndesmotic screws. The purposes of the current investigation are: To assess the effect of syndesmotic screw fixation on ankle dorsiflexion utilizing a controlled load and instrumentation allowing for precise measurement of ankle dorsiflexion. To assess the effect of anterior & posterior syndesmotic malreduction after syndesmotic screw fixation on ankle dorsiflexion.

Methods:

Fifteen cadaveric leg specimens were utilized for the study. Ankle dorsiflexion was measured utilizing a precise micro- sensor system after application of a consistent load in the intact state, after compression fixation with a syndesmotic screw and after anterior & posterior malreduction of the syndesmosis.

Results:

Following screw compression of the nondisplaced syndesmosis, dorsiflexion ROM was 99.7±0.87% (mean ± standard error) of baseline ankle ROM. Anterior and posterior displacement of the syndesmosis resulted in dorsiflexion ROM that was 99.1±1.75% and 98.6±1.56% of baseline ankle ROM, respectively. One-way ANOVA was performed showing no statistical significance between groups (p-value =0.88). Two-way ANOVA comparing the groups with respect to both the reduction condition (intact, anatomic reduction, anterior displacement, posterior displacement) and the displacement order (anterior first, posterior first) did not demonstrate a statistically significant effect (p-value= 0.99).

Conclusion:

Maximal dorsiflexion of the ankle is not required prior to syndesmotic fixation. Anterior or posterior syndesmotic malreduction following syndesmotic screw fixation has no effect on ankle dorsiflexion thus poor patient outcomes after syndesmotic malreduction does not appear to be the result of loss of dorsiflexion due to mechanical block.

The Effect of Orthotics on Ankle and Subtalar Joint Orientation and Load Distribution Utilizing a Novel System to Simulate Weight Bearing in a Cadaveric Model

Category:

Ankle, Basic Sciences/Biologics, Hindfoot, Biomechanics

Introduction/Purpose:

Orthotics are commonly prescribed by orthopaedic surgeons to address the hindfoot and midfoot deformity resulting from posterior tibial tendon dysfunction. The public however will often purchase over the counter orthotics for generalized complaints of foot pain that is not associated with any significant deformity or foot pathology. The mechanical axis of the lower limb may be altered in patients who use orthotics despite a normal foot alignment. We hypothesize that patients with normal alignment who use orthotics may adversely change ankle and subtalar joint orientation and load distribution.

Methods:

Five fresh frozen lower limb cadaveric specimens without known skeletal condition were used. The femoral head was potted with PMMA and TekScan pressure sensors were inserted into the ankle and subtalar joint. The specimens were placed on a custom jig, which allowed for load cell modulated loading of the leg; 75 lb load (half body weight) was applied at the femoral head while the foot was supported against a fixed plate keeping the ankle in neutral position. Testing was achieved by placing an orthotic under the medial half of the plantar talonavicular joint level. Mean pressure (MP), peak pressure (PP), contact area (CA), and center of force (COF) were measured in both the ankle and subtalar joints under three conditions; barefoot (BASE), with a 1.5 cm (ORT1) and 3 cm (ORT2) height orthotic. Each condition was tested three times per specimen. Displacement of COF was calculated relative to its location at baseline.

Results:

The MP, PP and CA showed a constant decrease from BASE to ORT1 and ORT2. Despite this relation, the only comparison that was significantly different was that between peak pressure values of the baseline and ORT2 conditions of the subtalar joint. The average displacement of COF from BASE was 0.14 mm and 0.42 mm medially, and 0.26 mm and 0.46 mm posteriorly at the ankle joint with ORT1 and ORT2 respectively. The average displacement of COF from BASE was 0.03 mm laterally and 0.08 mm posteriorly with ORT1, and 0.2 mm medially and 0.46 mm posteriorly with ORT2 at the subtalar joint.

Conclusion:

Foot deformities have an impact on the articular forces in the lower limb. Our results agree with previous studies about the role of foot deformity on the distribution of body weight forces and its consequences across the ankle and subtalar joint. Our novel study also demonstrates that orthotics and orthotics of varying sizes can change the mean pressure, peak pressure, contact area center of force in the ankle and subtalar joint. This study proves the feasibility of its design for studying intra-articular pressure changes in a lower limb cadaveric model with simulated weight bearing.

Accuracy and Measurement Error of the Medial Clear Space of the Ankle

Category:

Ankle, Trauma

Introduction/Purpose:

Measurement of the medial clear space (MCS) is commonly used to assess deltoid ligament competency and mortise stability when managing ankle fractures. Lacking knowledge of the true anatomic width measured, previous studies have been unable to measure accuracy of measurement. The purpose of this study is to determine MCS measurement error and accuracy and any influencing factors.

Methods:

Using three normal trans-tibial ankle cadaver specimens, deltoid and syndesmotic ligaments were transected and the mortise widened and affixed at a width of 6 mm (specimen #1) and 4 mm (specimen #2). The mortise was left intact in specimen #3. Radiographs were obtained of each cadaver at varying degrees of rotation. Radiographs were randomized and providers measured the MCS using a standardized technique.

Results:

Lack of accuracy as well as lack of precision in measurement of the medial clear space compared to a known anatomic value was present for all three specimens tested. There was no significant differences in mean delta with regard to level of training for specimens #1 and #2; however, with specimen #3 staff physicians showed increased measurement accuracy as compared to trainees.

Conclusion:

Accuracy and precision of MCS measurements are poor. Provider experience does not appear to influence accuracy and precision of measurements for the displaced mortise. This high degree of measurement error and lack of precision should be considered when deciding treatment options based on MCS measurements.

Proximity of the Lateral Calcaneal Artery With a Modified Extensile Lateral Approach Compared to Standard Extensile Approach

Category:

Ankle, Basic Sciences/Biologics, Trauma

Introduction/Purpose:

The extensile lateral approach (EL) has been associated with increased wound complications such as apical necrosis which may be due partially from violation of the lateral calcaneal artery (LCA). Traditionally, the vertical limb has been placed half-way between the fibula and Achilles tendon, which may be suboptimal given the proximity to the LCA. We hypothesized that placing the vertical limb further posterior (ie, modified EL [MEL]) would increase the distance from the LCA. The purposes of this study were to quantify the location of the LCA in relation to the vertical limb of the traditional EL approach and to determine if utilizing the MEL approach endangered the LCA to a lesser extent.

Methods:

20 cadavers were used. For the EL approach, the fibula and Achilles tendon were palpated and a line parallel to the plantar foot was drawn between the two. A vertical line (VL), representing the vertical limb of the approach, was drawn at the midway point as a perpendicular extending proximally from the junction of the glabrous/non-glabrous skin (JGNG). For the MEL approach, the anterior border of the Achilles tendon was palpated and a similar vertical line (MVL) was drawn 0.75 cm anterior. Dissection was performed and if the LCA was identified crossing the line VL/MVL, the distance from the JGNG was documented.

Results:

For the EL approach, the LCA was identified in 17/20 (85%) cadavers at an average distance of 5.0 cm (range 3-7 cm, SD = 1.3 cm) from JGNG. For the ML approach, the LCA was identified in 4/20 (20%) cadavers at an average distance of 5.9 cm (range 3-6.5 cm, SD = 1.7 cm) from the JGNG (P < .001).

Conclusion:

The LCA was encountered 4 times more often during the EL approach as compared to the MEL approach.

Virtual Human Models for Electromagnetic Studies and Their Applications

Numerical simulation of electromagnetic, thermal, and mechanical responses of the human body to different stimuli in magnetic resonance imaging safety, antenna research, electromagnetic tomography, and electromagnetic stimulation is currently limited by the availability of anatomically adequate and numerically efficient cross-platform computational models or "virtual humans." The objective of this study is to provide a comprehensive review of modern human models and body region models available in the field and their important features.

Overtightening of the syndesmosis revisited and the effect of syndesmotic malreduction on ankle dorsiflexion

BACKGROUND

Ankle syndesmotic injuries are a significant source of morbidity and require anatomic reduction to optimize outcomes. Although a previous study concluded that maximal dorsiflexion during syndesmotic fixation was not required, methodologic weaknesses existed and several studies have demonstrated improved ankle dorsiflexion after removal of syndesmotic screws. The purposes of the current investigation are: (1) To assess the effect of compressive syndesmotic screw fixation on ankle dorsiflexion utilizing a controlled load and instrumentation allowing for precise measurement of motion. (2) To assess the effect of anterior & posterior syndesmotic malreduction after compressive syndesmotic screw fixation on ankle dorsiflexion.

MATERIAL AND METHODS

Fifteen lower limb cadaveric leg specimens were utilized for the study. Ankle dorsiflexion was measured utilizing a precise micro-sensor system after application of a consistent load in the (1) intact state, (2) after compression fixation with a syndesmotic screw and (3) after anterior & (4) posterior malreduction of the syndesmosis.

RESULTS

Following screw compression of the nondisplaced syndesmosis, dorsiflexion ROM was 99.7±0.87% (mean±standard error) of baseline ankle ROM. Anterior and posterior malreduction of the syndesmosis resulted in dorsiflexion ROM that was 99.1±1.75% and 98.6±1.56% of baseline ankle ROM, respectively. One-way ANOVA was performed showing no statistical significance between groups (p-value=0.88). Two-way ANOVA comparing the groups with respect to both the reduction condition (intact, anatomic reduction, anterior displacement, posterior displacement) and the displacement order (anterior first, posterior first) did not demonstrate a statistically significant effect (p-value=0.99).

CONCLUSION

Maximal dorsiflexion of the ankle is not required prior to syndesmotic fixation as no loss of motion was seen with compressive fixation in our cadaver model. Anterior or posterior syndesmotic malreduction following syndesmotic screw fixation had no effect on ankle dorsiflexion. Poor patient outcomes after syndesmotic malreduction may be due to other factors and not loss of dorsiflexion motion.

LEVEL OF EVIDENCE

IV.

Bone fracture healing in mechanobiological modeling: A review of principles and methods

Bone fracture is a very common body injury. The healing process is physiologically complex, involving both biological and mechanical aspects. Following a fracture, cell migration, cell/tissue differentiation, tissue synthesis, and cytokine and growth factor release occur, regulated by the mechanical environment. Over the past decade, bone healing simulation and modeling has been employed to understand its details and mechanisms, to investigate specific clinical questions, and to design healing strategies. The goal of this effort is to review the history and the most recent work in bone healing simulations with an emphasis on both biological and mechanical properties. Therefore, we provide a brief review of the biology of bone fracture repair, followed by an outline of the key growth factors and mechanical factors influencing it. We then compare different methodologies of bone healing simulation, including conceptual modeling (qualitative modeling of bone healing to understand the general mechanisms), biological modeling (considering only the biological factors and processes), and mechanobiological modeling (considering both biological aspects and mechanical environment). Finally we evaluate different components and clinical applications of bone healing simulation such as mechanical stimuli, phases of bone healing, and angiogenesis.

Adhesive capsulitis of the shoulder: review of pathophysiology and current clinical treatments

Adhesive shoulder capsulitis, or arthrofibrosis, describes a pathological process in which the body forms excessive scar tissue or adhesions across the glenohumeral joint, leading to pain, stiffness and dysfunction. It is a debilitating condition that can occur spontaneously (primary or idiopathic adhesive capsulitis) or following shoulder surgery or trauma (secondary adhesive capsulitis). Here, we review the pathophysiology of adhesive shoulder capsulitis, highlighting its clinical presentation, natural history, risk factors, pathoanatomy and pathogenesis. Both current non-operative and operative treatments for adhesive capsulitis are described, and evidence-based studies are presented in support for or against each corresponding treatment. Finally, the review also provides an update on the gene expression profile of adhesive capsulitis and how this new understanding can help facilitate development of novel pharmacological therapies.