Structural and biochemical evaluation of the elbow capsule after trauma

Causes, symptoms, and treatments of nerve entrapments around the elbow: Current concepts

The elbow is a joint extremely susceptible to stiffness, even after a trivial trauma. As for other joints, several factors can generate stiffness such as immobilisation, joint incongruity, heterotopic ossification, adhesions, or pain. Prolonged joint immobilisation, pursued to assure bony and ligamentous healing, represents the most acknowledged risk factor for joint stiffness. The elbow is a common site of nerve entrapment syndromes. The reasons are multifactorial, but peculiar elbow anatomy and biomechanics play a role. Passing from the arm into the forearm, the ulnar, median, and radial nerves run at the elbow in close rapport with the joint, fibrous arches and through narrow fibro-osseous tunnel. The elbow joint, in fact, has a large range of flexion which exposes nerves lying posterior to the axis of rotation to traction and those anterior to compression.

Genetic causal association between frozen shoulder and carpal tunnel syndrome: a two-sample mendelian randomization

OBJECTIVE

Observational studies have suggested an association between frozen shoulder (FS) and carpal tunnel syndrome (CTS). However, due to challenges in establishing a temporal sequence, the causal relationship between these two conditions remains elusive. This study, based on aggregated data from large-scale population-wide genome-wide association studies (GWAS), investigates the genetic causality between FS and CTS.

METHODS

Initially, a series of quality control measures were employed to select single nucleotide polymorphisms (SNPs) closely associated with the exposure factors. Two-sample Mendelian randomization (MR) was utilized to examine the genetic causality between FS and CTS, employing methods including Inverse-Variance Weighted (IVW), MR-Egger, Weighted Median, Simple Mode, and Weighted Mode approaches. Subsequently, sensitivity analyses were conducted to assess the robustness of the MR analysis results.

RESULTS

IVW analysis results indicate a positive causal relationship between CTS and FS (p < 0.05, OR > 1), while a negative causal relationship between the two conditions was not observed. Heterogeneity tests suggest minimal heterogeneity in our IVW analysis results (p > 0.05). Multivariable MR testing also indicates no pleiotropy in our IVW analysis (p > 0.05), and stepwise exclusion tests demonstrate the reliability and stability of the MR analysis results. Gene Ontology (GO) pathway analysis reveals enrichment of genes regulated by the associated SNPs in the TGFβ-related pathways.

CONCLUSION

This study provides evidence of the genetic causal association between frozen shoulder and carpal tunnel syndrome and provides new insights into the genetics of fibrotic disorders.

Biomechanical study of the effect of traction on elbow joint capsule contracture

Dynamic orthoses have a significant effect on the treatment of elbow capsular contracture. Because of the lack of quantitative research on traction forces, determining the appropriate traction force to help stretch soft tissues and maintain the joint's range of motion is a challenge in the rehabilitation process. We developed a human elbow finite element (FE) model incorporating the activity behavior of the muscles and considering different capsular contracture locations, including total, anterior and posterior capsular contractures, to analyze the internal biomechanical responses of different capsular contracture models during flexion (30 to 80 degrees). Traction loads of 10, 20, 30 and 40 N were applied to the ulna and radius at the maximum flexion angle (80 degrees) to explore the appropriate traction loads at week 4 after a joint capsule injury. We observed a significant increase in posterior capsule stress with anterior capsular contracture (ACC), and the maximum peak stress was 1.3 times higher than that in the healthy model. During the fourth week after elbow capsule injury, the appropriate traction forces for total capsule contracture (TCC), ACC and posterior capsule contracture (PCC) were 20, 10 and 20 N, respectively; these forces maintained a stable biomechanical environment for the elbow joint and achieved a soft tissue pulling effect, thus increasing elbow mobility. The results can be used as a quantitative guide for the rehabilitation physicians to determine the traction load for a specific patient.

[Arthrofibrosis of the hip joint : Diagnostic and therapeutic challenge]

Arthrofibrosis is a frequent complication after total knee arthroplasty (TKA). Recently, arthrofibrosis could be successfully verified histologically after primary total hip arthroplasty (THA) and the clinical presentation on the hip could be described for the first time. Possible diagnostic and therapeutic approaches have not yet been published. The diagnostic work-up differs only slightly from that for the knee joint. Other causes, such as aseptic loosening, malalignment or periprosthetic joint infection should be excluded. The gold standard is still invasive diagnostics with histological evidence of arthrofibrosis according to the synovia-like interface membrane (SLIM) criteria. Conservative treatment approaches include mobilization under anesthesia and medication according to Traut, analogous to the knee joint. Surgical treatment should be carried out under strict interpretation of the indications and after detailed clarification for the patient. In contrast to the knee joint, open arthrolysis should be preferred to arthroscopic arthrolysis of the hip joint. It must be taken into consideration that the evidence for conservative as well as surgical treatment, including possible revision arthroplasty, cannot be assessed due to the absence of clinical data. Studies under controlled conditions on the possible treatment approaches in the presence of arthrofibrosis are desirable and necessary in order to be able to assess the significance of the symptoms. In addition to treatment, great importance should also be attached to the diagnostics. Histological confirmation of the diagnosis of arthrofibrosis should only be considered to a limited extent in the case of an assumed, only moderately successful surgical intervention.

Intra-articular MMP-1 in the spinal facet joint induces sustained pain and neuronal dysregulation in the DRG and spinal cord, and alters ligament kinematics under tensile loading

Chronic joint pain is a major healthcare challenge with a staggering socioeconomic burden. Pain from synovial joints is mediated by the innervated collagenous capsular ligament that surrounds the joint and encodes nociceptive signals. The interstitial collagenase MMP-1 is elevated in painful joint pathologies and has many roles in collagen regulation and signal transduction. Yet, the role of MMP-1 in mediating nociception in painful joints remains poorly understood. The goal of this study was to determine whether exogenous intra-articular MMP-1 induces pain in the spinal facet joint and to investigate effects of MMP-1 on mediating the capsular ligament’s collagen network, biomechanical response, and neuronal regulation. Intra-articular MMP-1 was administered into the cervical C6/C7 facet joints of rats. Mechanical hyperalgesia quantified behavioral sensitivity before, and for 28 days after, injection. On day 28, joint tissue structure was assessed using histology. Multiscale ligament kinematics were defined under tensile loading along with microstructural changes in the collagen network. The amount of degraded collagen in ligaments was quantified and substance P expression assayed in neural tissue since it is a regulatory of nociceptive signaling. Intra-articular MMP-1 induces behavioral sensitivity that is sustained for 28 days (p < 0.01), absent any significant effects on the structure of joint tissues. Yet, there are changes in the ligament’s biomechanical and microstructural behavior under load. Ligaments from joints injected with MMP-1 exhibit greater displacement at yield (p = 0.04) and a step-like increase in the number of anomalous reorganization events of the collagen fibers during loading (p ≤ 0.02). Collagen hybridizing peptide, a metric of damaged collagen, is positively correlated with the spread of collagen fibers in the unloaded state after MMP-1 (p = 0.01) and that correlation is maintained throughout the sub-failure regime (p ≤ 0.03). MMP-1 injection increases substance P expression in dorsal root ganglia (p < 0.01) and spinal cord (p < 0.01) neurons. These findings suggest that MMP-1 is a likely mediator of neuronal signaling in joint pain and that MMP-1 presence in the joint space may predispose the capsular ligament to altered responses to loading. MMP-1-mediated pathways may be relevant targets for treating degenerative joint pain in cases with subtle or no evidence of structural degeneration.

Arthrofibrosis following primary total hip arthroplasty: a distinct clinical entity

INTRODUCTION

Arthrofibrosis is a relatively frequent complication after total knee arthroplasty. Although stiffness after total hip arthroplasty (THA), because of formation of heterotopic ossification or other causes, is not uncommon, to the authors' best knowledge, arthrofibrosis after THA has not been described. The aim of this study is to describe the arthrofibrosis of the hip after primary THA using an established clinical and histological classification of arthrofibrosis.

MATERIALS AND METHODS

We retrospectively examined all patients who were histologically confirmed to have arthrofibrosis after primary THA during revision surgery by examination of tissue samples in our clinic. Arthrofibrosis was diagnosed according to the histopathological SLIM-consensus classification, which defines seven different SLIM types of the periimplant synovial membrane. The SLIM type V determines the diagnosis of endoprosthesis-associated arthrofibrosis.

RESULTS

The study population consists of 66 patients who were revised due to arthrofibrosis after primary THA. All patients had a limitation in range of motion prior to revision with a mean flexion of 90° (range from 40 to 125), mean internal rotation of 10° (range from 0 to 40) and mean external rotation of 20° (range from 0 to 50). All patients had histological SLIM type V arthrofibrosis, corresponding to endoprosthesis-associated arthrofibrosis. Histological examination revealed that seven patients (10.6%) had particle-induced and 59 patients (89.4%) had non-particle-induced arthrofibrosis.

CONCLUSION

This is the first description of endoprosthetic-associated arthrofibrosis after primary THA on the basis of a well-established histological classification. Our study results could enable new therapeutic and diagnostic opportunities in patients with such an arthrofibrosis. Surgeons should keep arthrofibrosis as a possible cause for stiffness and pain after primary THA in mind.

LEVEL OF EVIDENCE

Diagnostic study, Level of Evidence IV.

Females and males exhibit similar functional, mechanical, and morphological outcomes in a rat model of posttraumatic elbow contracture

Posttraumatic joint contracture (PTJC) is a debilitating condition characterized by loss of joint motion following injury. Previous work in a rat model of elbow PTJC investigated disease etiology, progression, and recovery in only male animals; this study explored sex-based differences. Rat elbows were subjected to a unilateral anterior capsulotomy and lateral collateral ligament transection followed by 42 days of immobilization and 42 days of free mobilization. Grip strength and gait were collected throughout the free mobilization period while joint mechanical testing, microcomputed tomography and histological analysis were performed postmortem. Overall, few differences were seen between sexes in functional, mechanical, and morphological outcomes with PTJC being similarly debilitating in male and female animals. Functional measures of grip strength and gait showed that, while some baseline differences existed between sexes, traumatic injury produced similar deficits that remained significantly different long-term when compared to control animals. Similarly, male and female animals both had significant reductions in joint range of motion due to injury. Ectopic calcification (EC), which had not been previously evaluated in this injury model, was present in all limbs on the lateral side. Injury caused increased EC volume but did not alter mineral density regardless of sex. Furthermore, histological analysis of the anterior capsule showed minor differences between sexes for inflammation and thickness but not for other histological parameters. A quantitative understanding of sex-based differences associated with this injury model will help inform future therapeutics aimed at reducing or preventing elbow PTJC.

The post-traumatic stiff elbow: A review

Upper extremity function is highly dependent on elbow motion in order to adequately position the hand in space. Loss of this motion due to stiffness following trauma can cause patients substantial disability, leading to difficulties with performing activities of daily living. Post-traumatic elbow stiffness is challenging to treat, and therefore prevention is of paramount importance. Key measures that can be used to prevent elbow stiffness are early surgical intervention for fracture or joint instability, as well as active mobilisation, which helps to prevent oedema and an increase in viscosity of inflammatory exudates. Other options include splinting and continuous passive mobilisation. Once non-operative methods of addressing post-traumatic stiffness have been exhausted, arthrolysis of the stiff elbow can be performed via open or arthroscopic means depending on the type of pathology involved (intrinsic or extrinsic contracture) and experience of the surgeon with elbow arthroscopy. The particular open approach used depends on several factors, which include the formation and location of any heterotopic ossification present. Improvements in range of motion can be expected with both open and arthroscopic techniques, which can be effective and rewarding for patients. Post-operative rehabilitation, particularly early active mobilisation, should be considered essential in order to optimise patient outcomes following surgery. This review aims to explore elbow stiffness following traumatic aetiology, assessing its pathogenesis and prevention, as well as reviewing surgical treatment options and post-operative rehabilitation.

Preclinical Models of Elbow Injury and Pathology

The human elbow is a complex joint that is essential for activities of daily living requiring the upper extremities; however, this complexity generates significant challenges when considering its response to injury and management of treatment. The current understanding of elbow injury and pathologies lags behind that of other joints and musculoskeletal tissues. Most research on the elbow joint is mainly focused on the late-stage disease states when irreversible damage has occurred. Consequentially, the specific contribution and relative time course of different elbow tissues in disease progression, as well as optimized approaches for treating such conditions, remains largely unknown. Given the challenge of studying elbow pathologies in humans, preclinical models can serve as ideal alternatives. However, a limited number of preclinical models exist to investigate elbow injury and pathology. This review highlights significant clinical elbow diseases and the preclinical models currently available to recapitulate these diseases, while also providing recommendations for the development of future preclinical models. Overall, this review will serve as a guide for preclinical models studying injuries and pathologies of the elbow, with the long-term goal of developing novel intervention strategies to improve the treatment of elbow diseases in human patients.

Intra-articular collagenase in the spinal facet joint induces pain, DRG neuron dysregulation and increased MMP-1 absent evidence of joint destruction

Degeneration is a hallmark of painful joint disease and is mediated by many proteases that degrade joint tissues, including collagenases. We hypothesized that purified bacterial collagenase would initiate nociceptive cascades in the joint by degrading the capsular ligament's matrix and activating innervating pain fibers. Intra-articular collagenase in the rat facet joint was investigated for its effects on behavioral sensitivity, joint degeneration, and nociceptive pathways in the peripheral and central nervous systems. In parallel, a co-culture collagen gel model of the ligament was used to evaluate effects of collagenase on microscale changes to the collagen fibers and embedded neurons. Collagenase induced sensitivity within one day, lasting for 3 weeks (p < 0.001) but did not alter ligament structure, cartilage health, or chondrocyte homeostasis. Yet, nociceptive mediators were increased in the periphery (substance P, pERK, and MMP-1; p ≤ 0.039) and spinal cord (substance P and MMP-1; p ≤ 0.041). The collagen loss (p = 0.008) induced by exposing co-cultures to collagenase was accompanied by altered neuronal activity (p = 0.002) and elevated neuronal MMP-1 (p < 0.001), suggesting microscale collagen degradation mediates sensitivity in vivo. The induction of sustained sensitivity and nociception without joint damage may explain the clinical disconnect in which symptomatic joint pain patients present without radiographic evidence of joint destruction.

Adipose stem cells exhibit mechanical memory and reduce fibrotic contracture in a rat elbow injury model

Fibrosis is driven by a misdirected cell response causing the overproduction of extracellular matrix and tissue dysfunction. Numerous pharmacological strategies have attempted to prevent fibrosis but have attained limited efficacy with some detrimental side effects. While stem cell treatments have provided more encouraging results, they have exhibited high variability and have not always improved tissue function. To enhance stem cell efficacy, we evaluated whether mechanical memory could direct cell response. We hypothesized that mechanically pre-conditioning on a soft matrix (soft priming) will delay adipose-derived stem cell (ASC) transition to a pro-fibrotic phenotype, expanding their regenerative potential, and improving healing in a complex tissue environment. Primary ASCs isolated from rat and human subcutaneous fat exhibited mechanical memory, demonstrated by a delayed cell response to stiffness following two weeks of soft priming including decreased cell area, actin coherency, and extracellular matrix production compared to cells on stiff substrates. Soft primed ASCs injected into our rat model of post-traumatic elbow contracture decreased histological evidence of anterior capsule fibrosis and increased elbow range-of-motion when evaluated by joint mechanics. These findings suggest that exploiting mechanical memory by strategically controlling the culture environment during cell expansion may improve the efficacy of stem cell-based therapies targeting fibrosis.

Modified Lateral Approach of the Elbow for Surgical Release and Synovectomy

Elbow stiffness is a common reason for consultation. In recent years, arthroscopic techniques in elbow surgery have progressed, but there are still some contraindications to performance of arthroscopic synovectomy and release in this joint (elbows with anatomic deformity after multiple procedures, malunion, presence of osteosynthesis material, severe stiffness of >80 degrees, instability, or previous transposition of the ulnar nerve). Therefore, knowledge of a safe and reliable open approach to achieve elbow release and/or synovectomy is essential. We report the technical details of the modified lateral approach between extensor carpi radialis brevis and longus muscles, as well as the clinical results of 43 elbow release and/or synovectomy procedures, illustrating its feasibility. The modified lateral approach, providing visual control of the radial nerve and good anterior exposure of the elbow joint, is detailed. From 1994 to 2016, this approach was used in 43 release and/or synovectomy procedures of the elbow in 41 patients, 30 men and 11 women, with a mean age of 40.56 years (range, 17 to 84 y). Using this procedure, 38 elbows (93%) recovered full extension and 5 subtotal extension with an average deficit of 11 degrees (range, 5 to 20 degrees). All elbows were stable. No neurological complications were reported. The modified lateral approach preserves the insertion of the lateral epicondyle muscles that are major dynamic stabilizers and reduces the risk of instability. Initially described for the treatment of radial tunnel syndrome, it should also be recommended for elbow release and synovectomy.

The stiff elbow: Current concepts

Elbow stiffness is defined as any loss of movement that is greater than 30° in extension and less than 120° in flexion. Causes of elbow stiffness can be classified as traumatic or atraumatic and as congenital or acquired. Any alteration affecting the stability elements of the elbow can lead to a reduction in the arc of movement. The classification is based on the specific structures involved (Kay’s classification), anatomical location (Morrey’s classification), or on the degree of severity of rigidity (Vidal’s classification). Diagnosis is the result of a combination of medical history, physical examination (evaluating both active and passive movements), and imaging. The loss of soft tissue elasticity could be the result of bleeding, edema, granulation tissue formation, and fibrosis. Preventive measures include immobilization in extension, use of post-surgical drain, elastic compression bandage and continuous passive motion. Conservative treatment is used when elbow stiffness has been present for less than six months and consists of the use of serial casts, static or dynamic splints, CPM, physical therapy, manipulations and functional re-education. If conservative treatment fails or is not indicated, surgery is performed. Extrinsic rigidity cases are usually managed with an open or arthroscopic release, while those that are due to intrinsic causes can be managed with arthroplasties. The elbow is a joint that is particularly prone to developing stiffness due to its anatomical and biomechanical complexity, therefore the treatment of this pathology represents a challenge for the physiotherapist and the surgeon alike.

Histologic examination of the shoulder capsule shows new layer of elastic fibres between synovial and fibrous membrane

Purpose

In the present study, a systematic histological analysis of the glenohumeral joint capsule was conducted.

Materials and methods

12 cadaveric shoulders were examined. Inclusion criteria were: 1) intact joint capsule and 2) fixation in neutral position. The tissue samples were Elastica Hematoxylin-van-Gieson-(ElHvG) stained and diameter, quantity, and distribution patterns were analyzed.

Results

We detected a new layer (elastic boundary layer, EBL) between the synovial and fibrous membrane. The elastic fibres of the EBL differ considerably in diameter, quantity, and distribution pattern.

Conclusions

A previously undescribed layer was noticed, which we named elastic boundary layer for now.

Inflammatory cytokines and matrix metalloproteinases in the synovial fluid after intra-articular elbow fracture

BACKGROUND AND HYPOTHESIS

Post-traumatic elbow contracture remains a common and challenging complication with often unsatisfactory outcomes. Although the etiology is unknown, elevated or abnormal post-fracture synovial fluid cytokine levels may result in the migration of fibroblasts to the capsule and contribute to capsular pathology. Thus, the purpose of this study was to characterize the cytokine composition in the synovial fluid fracture hematoma of patients with intra-articular elbow fractures.

METHODS

The elbow synovial fluid fracture hematoma of 11 patients with intra-articular elbow fractures was analyzed for CTXII (C-terminal telopeptides of type II collagen [a cartilage breakdown product]) as well as 15 cytokines and matrix metalloproteinases (MMPs) including interferon γ, interleukin (IL) 1β, IL-2, IL-4, IL-6, IL-8, IL-10, IL-12p70, IL-13, tumor necrosis factor α, MMP-1, MMP-2, MMP-3, MMP-9, and MMP-10. The uninjured, contralateral elbow served as a matched control. Mean concentrations of each factor were compared between the fluid from fractured elbows and the fluid from control elbows.

RESULTS

The levels of 14 of 15 measured cytokines and MMPs-interferon γ, IL-1β, IL-2, IL-4, IL-6, IL-8, IL-10, IL-12p70, IL-13, tumor necrosis factor α, MMP-1, MMP-3, MMP-9, and MMP-10-were significantly higher in the fractured elbows. In addition, post hoc power analysis revealed that 10 of 14 significant differences were detected with greater than 90% power. The mean concentration of CTXII was not significantly different between groups.

CONCLUSIONS

These results demonstrate a proinflammatory environment after fracture that may be the catalyst to the development of post-traumatic elbow joint contracture. The cytokines with elevated levels were similar, although not identical, to the cytokines with elevated levels in studies of other weight-bearing joints, indicating the elbow responds uniquely to trauma.

Proteasome inhibition preserves longitudinal growth of denervated muscle and prevents neonatal neuromuscular contractures

Muscle contractures are a prominent and disabling feature of many neuromuscular disorders, including the 2 most common forms of childhood neurologic dysfunction: neonatal brachial plexus injury (NBPI) and cerebral palsy. There are currently no treatment strategies to directly alter the contracture pathology, as the pathogenesis of these contractures is unknown. We previously showed in a mouse model of NBPI that contractures result from impaired longitudinal muscle growth. Current presumed explanations for growth impairment in contractures focus on the dysregulation of muscle stem cells, which differentiate and fuse to existing myofibers during growth, as this process has classically been thought to control muscle growth during the neonatal period. Here, we demonstrate in a mouse model of NBPI that denervation does not prevent myonuclear accretion and that reduction in myonuclear number has no effect on functional muscle length or contracture development, providing definitive evidence that altered myonuclear accretion is not a driver of neuromuscular contractures. In contrast, we observed elevated levels of protein degradation in NBPI muscle, and we demonstrate that contractures can be pharmacologically prevented with the proteasome inhibitor bortezomib. These studies provide what we believe is the first strategy to prevent neuromuscular contractures by correcting the underlying deficit in longitudinal muscle growth.

Concentration-Dependent Effects of Fibroblast-Like Synoviocytes on Collagen Gel Multiscale Biomechanics and Neuronal Signaling: Implications for Modeling Human Ligamentous Tissues

Abnormal loading of a joint's ligamentous capsule causes pain by activating the capsule's nociceptive afferent fibers, which reside in the capsule's collagenous matrix alongside fibroblast-like synoviocytes (FLS) and transmit pain to the dorsal root ganglia (DRG). This study integrated FLS into a DRG-collagen gel model to better mimic the anatomy and physiology of human joint capsules; using this new model, the effect of FLS on multiscale biomechanics and cell physiology under load was investigated. Primary FLS cells were co-cultured with DRGs at low or high concentrations, to simulate variable anatomical FLS densities, and failed in tension. Given their roles in collagen degradation and nociception, matrix-metalloproteinase (MMP-1) and neuronal expression of the neurotransmitter substance P were probed after gel failure. The amount of FLS did not alter (p > 0.3) the gel failure force, displacement, or stiffness. FLS doubled regional strains at both low (p < 0.01) and high (p = 0.01) concentrations. For high FLS, the collagen network showed more reorganization at failure (p < 0.01). Although total MMP-1 and neuronal substance P were the same regardless of FLS concentration before loading, protein expression of both increased after failure, but only in low FLS gels (p ≤ 0.02). The concentration-dependent effect of FLS on microstructure and cellular responses implies that capsule regions with different FLS densities experience variable microenvironments. This study presents a novel DRG-FLS co-culture collagen gel system that provides a platform for investigating the complex biomechanics and physiology of human joint capsules, and is the first relating DRG and FLS interactions between each other and their surrounding collagen network.

Multiple rare causes of post-traumatic elbow stiffness in an adolescent patient: A case report and review of literature

BACKGROUND

Joint stiffness after elbow surgery is not a rare complication, and is always accompanied by deformity. The causes of joint stiffness are multiple in different patients, and divided into intrinsic and extrinsic causes. Herein, we report an unusual case of posttraumatic elbow stiffness due to multiple and rare causes.

CASE SUMMARY

A 19-year-old male was hospitalized with the loss of motion of the left elbow for over ten years. Left limb computed tomography revealed left elbow stiffness with bony block and connection. The patient underwent surgery, and the etiology of joint stiffness was found to be a rare combination of common and uncommon causes. During an 18-mo follow-up period, the patient’s left elbow had normal motion and he was symptom-free.

CONCLUSION

However, this case combined with multiple and rare causes highlights that the patient with scar physique is likely to be accompanied with more severe soft tissue, nerve contracture, and heterotypic ossification, even during recurrence.

The Role of Periarticular Soft Tissues in Persistent Motion Loss in a Rat Model of Posttraumatic Elbow Contracture

BACKGROUND

Elbow injuries disrupt the surrounding periarticular soft tissues, which include the muscles, tendons, capsule, ligaments, and cartilage. Damage to these tissues as a result of elbow trauma causes clinically significant contracture in 50% of patients. However, it is unclear which of these tissues is primarily responsible for the decreased range of motion. We hypothesized that all tissues would substantially contribute to elbow contracture after immobilization, but only the capsule, ligaments, and cartilage would contribute after free mobilization, with the capsule as the primary contributor at all time points.

METHODS

Utilizing a rat model of posttraumatic elbow contracture, a unilateral soft-tissue injury was surgically induced to replicate the damage that commonly occurs during elbow joint dislocation. After surgery, the injured limb was immobilized for 42 days. Animals were evaluated after either 42 days of immobilization (42 IM) or 42 days of immobilization with an additional 21 or 42 days of free mobilization (42/21 or 42/42 IM-FM). For each group of animals, elbow mechanical testing in flexion-extension was completed post-mortem with (1) all soft tissues intact, (2) muscles/tendons removed, and (3) muscle/tendons and anterior capsule removed. Total extension was assessed to determine the relative contributions of muscles/tendons, capsule, and the remaining intact tissues (i.e., ligaments and cartilage).

RESULTS

After immobilization, the muscles/tendons and anterior capsule contributed 10% and 90% to elbow contracture, respectively. After each free mobilization period, the muscles/tendons did not significantly contribute to contracture. The capsule and ligaments/cartilage were responsible for 47% and 52% of the motion lost at 42/21 IM-FM, respectively, and 26% and 74% at 42/42 IM-FM, respectively.

CONCLUSIONS

Overall, data demonstrated a time-dependent response of periarticular tissue contribution to elbow contracture, with the capsule, ligaments, and cartilage as the primary long-term contributors.

CLINICAL RELEVANCE

The capsule, ligaments, and cartilage were primarily responsible for persistent motion loss and should be considered during development of tissue-targeted treatment strategies to inhibit elbow contracture following injury.

Arthrofibrosis and large joint scarring

Large joint arthrofibrosis and scarring, involving the shoulder, elbow, hip, and knee, can result in the loss of function and immobility. The pathway of joint contracture formation is still being elucidated and is due to aberrations in collagen synthesis and misorientation of collagen fibrils. Novel antibodies are being developed to prevent arthrofibrosis, and current treatment methods for arthrofibrosis include medical, physical, and surgical treatments. This article describes the biology of joint contracture formation, along with current and future pharmacologic, biologic, and medical interventions.

Surgical Management of the Posttraumatic Stiff Elbow: A Step-Wise Algorithm for Open Osteocapsular Release

Posttraumatic elbow stiffness is common with the primary indication for contracture release being limited motion that affects functional activities which has not adequately improved after intensive therapy and rehabilitation. Preoperative evaluation focuses on the history of previous nonoperative and/or operative treatment, physical exam with particular attention paid to the status of the ulnar nerve, and imaging consisting of radiographs and computed tomography. There are multiple intrinsic and extrinsic causes of posttraumatic contracture. In general, limitation of motion in one direction can be attributed to a mechanical block and/or opposing contracture or tightness. Open elbow contracture release has been shown to improve motion, patient health status and disability scores with the specific surgical approach based upon the contracture pathology and surgeon preference. A step-wise algorithm is presented for open osteocapsular release. An anterior and posterior release is performed first through a lateral approach with the addition of a medial approach if ulnar nerve dysfunction exists or inadequate release has been obtained from the lateral approach. A previous posterior incision can be utilized by raising full thickness flaps. After release, gentle manipulation is performed and intraoperative stability is assessed with stress testing under fluoroscopy. Postoperatively, pain is managed with an in-dwelling nerve catheter and rehabilitation commences immediately. Significant improvement in range of motion can be expected with adequate surgical release and postoperative rehabilitation.

Therapeutic Management of the Posttraumatic Stiff Elbow After Open Osteocapsular Release

Arthrofibrosis is an inevitable consequence of elbow trauma that oftentimes requires surgical release to restore range of motion and function. Although the surgical procedure for elbow osteocapsular release can result in marked improvement in elbow motion, postrelease rehabilitation is paramount to maintaining and even improving the gains achieved in surgery. There are a variety of rehabilitation protocols and modalities that can be implemented that can be divided into an early versus late stage of rehabilitation after surgery. Irrespectively, patient ownership in the rehabilitative process and effective communication between surgeon and therapist are integral in achieving successful outcomes.

Muscle does not drive persistent posttraumatic elbow contracture in a rat model

INTRODUCTION

Posttraumatic elbow contracture is clinically challenging because injury often disrupts multiple periarticular soft tissues. Tissue specific contribution to contracture, particularly muscle, remains poorly understood.

METHODS

In this study we used a previously developed animal model of elbow contracture. After surgically inducing a unilateral soft tissue injury, injured limbs were immobilized for 3, 7, 21, and 42 days (IM) or for 42 IM with 42 days of free mobilization (42/42 IM-FM). Biceps brachii active/passive mechanics and morphology were evaluated at 42 IM and 42/42 IM-FM, whereas biceps brachii and brachialis gene expression was evaluated at all time points.

RESULTS

Injured limb muscle exhibited significantly altered active/passive mechanics and decreased fiber area at 42 IM but returned to control levels by 42/42 IM-FM. Gene expression suggested muscle growth rather than a fibrotic response at 42/42 IM-FM.

DISCUSSION

Muscle is a transient contributor to motion loss in our rat model of posttraumatic elbow contracture. Muscle Nerve 58:843-851, 2018.

Temporal Patterns of Motion in Flexion-extension and Pronation-supination in a Rat Model of Posttraumatic Elbow Contracture

BACKGROUND

The elbow is highly susceptible to contracture, which affects up to 50% of patients who experience elbow trauma. Previously, we developed a rat model to study elbow contracture that exhibited features similar to the human condition, including persistently decreased ROM and increased capsule thickness/adhesions. However, elbow ROM was not quantitatively evaluated over time throughout contracture development and subsequent mobilization of the joint.

QUESTIONS/PURPOSES

The purposes of this study were (1) to quantify the time-dependent mechanics of contracture, including comparison of contracture after immobilization and free mobilization; and (2) to determine what changes occur in capsule and joint surface morphology that may support the altered joint mechanics.

METHODS

A total of 96 male Long-Evans rats were randomized into control and injury (unilateral soft tissue injury/immobilization) groups. Flexion-extension and pronation-supination joint mechanics (n = 8/group) were evaluated after 3, 7, 21, or 42 days of immobilization (IM) or after 42 days of IM with either 21 or 42 days of free mobilization (63 or 84 FM, respectively). After measuring joint mechanics, a subset of these limbs (n = 3/group) was prepared for histologic analysis and blinded sections were scored to evaluate capsule and joint surface morphology. Joint mechanics and capsule histology at 42 IM and 84 FM were reported previously but are included to demonstrate the full timeline of elbow contracture.

RESULTS

In flexion-extension, injured limb ROM was decreased compared with control (103° ± 11°) by 21 IM (70° ± 13°) (p = 0.001). Despite an increase in injured limb ROM from 42 IM (55° ± 14°) to 63 FM (83° ± 10°) (p < 0.001), injured limb ROM was still decreased compared with control (103° ± 11°) (p = 0.002). Interestingly, ROM recovery plateaued because there was no difference between injured limbs at 63 (83° ± 10°) and 84 FM (73° ± 19°) (p > 0.999). In pronation-supination, increased injured limb ROM occurred until 7 IM (202° ± 32°) compared with control (155° ± 22°) (p = 0.001), representative of joint instability. However, injured limb ROM decreased from 21 (182° ± 25°) to 42 IM (123° ± 47°) (p = 0.001), but was not different compared with control (155° ± 22°) (p = 0.108). Histologic evaluation showed morphologic changes in the anterior capsule (increased adhesions, myofibroblasts, thickness) and nonopposing joint surfaces (surface irregularities with tissue overgrowth, reduced matrix), but these changes did not increase with time.

CONCLUSIONS

Overall, flexion-extension and pronation-supination exhibited distinct time-dependent patterns during contracture development and joint mobilization. Histologic evaluation showed tissue changes, but did not fully explain the patterns in contracture mechanics. Future work will use this rat model to evaluate the periarticular soft tissues of the elbow to isolate tissue-specific contributions to contracture to ultimately develop strategies for tissue-targeted treatments.

CLINICAL RELEVANCE

A rat model of posttraumatic elbow contracture quantitatively described contracture development/progression and reiterates the need for rehabilitation strategies that consider both flexion-extension and pronation-supination elbow motion.

Pronation-Supination Motion Is Altered in a Rat Model of Post-Traumatic Elbow Contracture

The elbow joint is highly susceptible to joint contracture, and treating elbow contracture is a challenging clinical problem. Previously, we established an animal model to study elbow contracture that exhibited features similar to the human condition including persistent decreased range of motion (ROM) in flexion-extension and increased capsule thickness/adhesions. The objective of this study was to mechanically quantify pronation-supination in different injury models to determine if significant differences compared to control or contralateral persist long-term in our animal elbow contracture model. After surgically inducing soft tissue damage in the elbow, Injury I (anterior capsulotomy) and Injury II (anterior capsulotomy with lateral collateral ligament transection), limbs were immobilized for 6 weeks (immobilization (IM)). Animals were evaluated after the IM period or following an additional 6 weeks of free mobilization (FM). Total ROM for pronation-supination was significantly decreased compared to the uninjured contralateral limb for both IM and FM, although not different from control limbs. Specifically, for both IM and FM, total ROM for Injury I and Injury II was significantly decreased by ∼20% compared to contralateral. Correlations of measurements from flexion-extension and pronation-supination divulged that FM did not affect these motions in the same way, demonstrating that joint motions need to be studied/treated separately. Overall, injured limbs exhibited persistent motion loss in pronation-supination when comparing side-to-side differences, similar to human post-traumatic joint contracture. Future work will use this animal model to study how elbow periarticular soft tissues contribute to contracture.

Relative ratios of collagen composition of periarticular tissue of joints of the upper limb

We investigated the relative ratios of collagen composition of periarticular tissue of the elbow, wrist, metacarpophalangeal, proximal and distal interphalangeal joints. Periarticulat tissue, which we defined as the ligaments, palmar plate and capsule, was harvested from ten fresh-frozen cadaveric upper limbs, yielding 50 samples. The mean paired differences (95% confidence interval) of the relative ratios of collagen between the five different joints were estimated using mRNA expression of collagen in the periarticular tissue. We found that the relative collagen composition of the elbow was not significantly different to that of the proximal interphalangeal joint, nor between the proximal interphalangeal joint and distal interphalangeal joint, whereas the differences in collagen composition between all the other paired comparisons of the joints had confidence intervals that did not include zero.

Persistent motion loss after free joint mobilization in a rat model of post-traumatic elbow contracture

BACKGROUND

Post-traumatic joint contracture (PTJC) in the elbow is a challenging clinical problem due to the anatomical and biomechanical complexity of the elbow joint.

METHODS

We previously established an animal model to study elbow PTJC, wherein surgically induced soft tissue damage, followed by 6 weeks of unilateral immobilization in Long-Evans rats, led to stiffened and contracted joints that exhibited features similar to the human condition. In this study, after 6 weeks of immobilization, we remobilized the animal (ie, external bandage removed and free cage activity) for an additional 6 weeks, after which the limbs were evaluated mechanically and histologically. The objective of this study was to evaluate whether this decreased joint motion would persist after 6 weeks of free mobilization (FM).

RESULTS

After FM, flexion-extension demonstrated decreased total range of motion (ROM) and neutral zone length, and increased ROM midpoint for injured limbs compared with control and contralateral limbs. Specifically, after FM total ROM demonstrated a significant decrease of approximately 22% and 26% compared with control and contralateral limbs for injury I (anterior capsulotomy) and injury II (anterior capsulotomy with lateral collateral ligament transection), respectively. Histologic evaluation showed increased adhesion, fibrosis, and thickness of the capsule tissue in the injured limbs after FM compared with control and contralateral limbs, which is consistent with patterns previously reported in human tissue.

CONCLUSION

Even with FM, injured limbs in this model demonstrate persistent joint motion loss and histologic results similar to the human condition. Future work will use this animal model to investigate the mechanisms responsible for PTJC and responses to therapeutic intervention.

The posttraumatic stiff elbow: an update

Posttraumatic elbow stiffness is a disabling condition that remains challenging to treat despite improvement of our understanding of the pathogenesis of posttraumatic contractures and new treatment regimens. This review provides an update and overview of the etiology of posttraumatic elbow stiffness, its classification, evaluation, nonoperative and operative treatment, and postoperative management.

Development and use of an animal model to study post-traumatic stiffness and contracture of the elbow

Post-traumatic joint stiffness (PTJS) of the elbow is a debilitating condition that poses unique treatment challenges. While previous research has implicated capsular tissue in PTJS, much regarding the development and progression of this condition remains unknown. The objective of this study was to develop an animal model of post-traumatic elbow contracture and evaluate its potential for studying the etiology of PTJS. The Long-Evans rat was identified as the most appropriate species/breed for development due to anatomical and functional similarities to the human elbow joint. Two surgical protocols of varying severity were utilized to replicate soft tissue damage seen in elbow subluxation/dislocation injuries, including anterior capsulotomy and lateral collateral ligament transection, followed by 6 weeks of unilateral joint immobilization. Following sacrifice, flexion-extension mechanical joint testing demonstrated decreased range-of-motion and increased stiffness for injured-immobilized limbs compared to control and sham animals, where functional impact correlated with severity of injury. Histological evaluation showed increased cellularity, adhesion, and thickness of capsule tissue in injured limbs, consistent with clinical evidence. To our knowledge, this is the first animal model capable of examining challenges unique to the anatomically and biomechanically complex elbow joint. Future studies will use this animal model to investigate mechanisms responsible for PTJS.

Effect of pERK2 on extracellular matrix turnover of the fibrotic joint capsule in a post-traumatic joint contracture model

Lentivirus (LV)-mediated extracellular signal-regulated kinase (ERK)2 small interfering RNA (siRNA) has previously been demonstrated to reduce post-traumatic joint contractures: In the present study, the effect of ERK2 siRNA on extracellular matrix turnover within fibrotic joint capsules in post-traumatic joint contractures was examined. Rats were randomly assigned to one of three groups as follows: The non-operated control (CON), operated contracture (ORC) and contracture-treatment (CNT) groups. Representative post-traumatic joint contracture was created through 8 weeks of immobilization following intra-articular injury. In the CNT group, LV-mediated ERK2 siRNA was injected into the model knee at days 3 and 7 after surgery. The posterior joint capsule was examined by western blotting, histology and immunohistochemistry to evaluate alterations in ERK2, phosphorylated (p)ERK2, total collagen, collagen I, collagen III, matrix metalloproteinase (MMP)-1, MMP-13 and tissue inhibitor of metalloproteinase (TIMP)-13. In the ORC group, pERK2 was elevated and total collagen, collagen I, MMP-1 and MMP-13 were significantly increased (P<0.01 vs. CON group); however, these were significantly decreased in the CNT group, and pERK2 was downregulated (P<0.01 vs. ORC group). Collagen III and TIMP-13 were markedly decreased in the ORC group (P<0.01 vs. CON group), but elevated in the CNT group (P<0.01 vs. ORC group). The present res4ults demonstrate unique pathological changes of the fibrotic joint capsule that are responsible for joint contracture following traumatic injury, and reveal that extracellular matrix turnover can be affected by pERK2.

POST-TRAUMATIC STIFFNESS OF THE ELBOW

Elbow stiffness is a common problem after joint trauma, causing functional impairment of the upper limb. The severity of the dysfunction depends on the nature of the initial trauma and the treatment used. Appropriate clinical evaluation and complementary examinations are essential for therapeutic planning. Several surgical techniques are now available and the recommendation must be made in accordance with patient characteristics, degree of joint limitation and the surgeon's skill. Joint incongruence and degeneration have negative effects on the prognosis, but heterotrophic ossification alone has been correlated with a favorable surgical prognosis.

Inner Synovial Membrane Footprint of the Anterior Elbow Capsule: An Arthroscopic Boundary

Introduction. The purpose of this study is to describe the inner synovial membrane (SM) of the anterior elbow capsule, both qualitatively and quantitatively. Materials and Methods. Twenty-two cadaveric human elbows were dissected and the distal humerus and SM attachments were digitized using a digitizer. The transepicondylar line (TEL) was used as the primary descriptor of various landmarks. The distance between the medial epicondyle and medial SM edge, SM apex overlying the coronoid fossa, the central SM nadir, and the apex of the SM insertion overlying the radial fossa and distance from the lateral epicondyle to lateral SM edge along the TEL were measured and further analyzed. Gender and side-to-side statistical comparisons were calculated. Results. The mean age of the subjects was 80.4 years, with six male and five female cadavers. The SM had a distinctive double arched attachment overlying the radial and coronoid fossae. No gender-based or side-to-side quantitative differences were noted. In 18 out of 22 specimens (81.8%), an infolding extension of the SM was observed overlying the medial aspect of the trochlea. The SM did not coincide with the outer fibrous attachment in any specimen. Conclusion. The humeral footprint of the synovial membrane of the anterior elbow capsule is more complex and not as capacious as commonly understood from the current literature. The synovial membrane nadir between the two anterior fossae may help to explain and hence preempt technical difficulties, a reduction in working arthroscopic volume in inflammatory and posttraumatic pathologies. This knowledge should allow the surgeon to approach this aspect of the anterior elbow compartment space with the confidence that detachment of this synovial attachment, to create working space, does not equate to breaching the capsule. Alternatively, stripping the synovial attachment from the anterior humerus does not constitute an anterior capsular release.

Open surgical release for contractures of the elbow

Compared with arthroscopic release, open release is more commonly used for the treatment of stiff elbow. Flexion is recovered by releasing posterior tethering soft-tissue structures and by removing anterior impingement between the coronoid and/or radial head and the distal humerus. Extension is improved by releasing anterior soft-tissue tethers and by removing impingement between the olecranon tip and the olecranon fossa. Open elbow release is most commonly performed via ligament-sparing approaches. Ulnar nerve identification and transposition is recommended in the presence of nerve dysfunction or when correction of significant loss of elbow flexion is anticipated. Long-term improvement in flexion and extension can be expected with proper patient selection. Less predictable results are obtained in adolescent patients and in those with underlying traumatic brain injury.

Inflammatory cytokine expression in the quadriceps of rats with posttraumatic knee stiffness: A preliminary study

The primary purpose of this study was to investigate cytokine expression in the quadriceps of rats with posttraumatic knee stiffness (PTKS) and to determine the effect of exercise training on these cytokines at different follow-up time points. The PTKS rats were randomly assigned into two even groups. The treatment group received exercise training, while the control group received no treatment. Quadriceps specimens were harvested randomly from each group at 8, 12, 16, and 20 weeks. RT-qPCR and immunohistochemical analyses were used to assess the protein and mRNA expression levels of the cytokines IL-1, IL-2, TNF-α, COX-1, and COX-2. TNF-α immunostaining did not differ between the treated and control group tissues, whereas weak immunostaining was observed for all other cytokines in the specimens from the treatment group compared with those from the control group at approximately 12 and 20 weeks. The cytokine levels decreased at approximately 8 weeks in the treatment group, whereas these levels remained elevated or plateaued in the control group. These differences were statistically significant (p<0.05). This study demonstrated that the expression of cytokines IL-1, IL-2, COX-1, and COX-2 increased in the quadriceps of rats with PTKS and that exercise training affected the observed profile trends of these cytokines.

The use of braces in the rehabilitation treatment of the post-traumatic elbow

The elbow, the middle joint of the upper limb, enables the hand to be placed at various distances from the body. The articular, muscular and neuromotor complexity of the elbow is such that it is often prone to stiffness, especially if immobilized for long periods of time. Therefore, mobilization of the posttraumatic elbow must be started early. In the presence of lesions to the ligamentous structures, the joint must be protected to prevent these structures from being placed under tension during movement. Rehabilitation of the elbow includes the use of braces. Different types of brace are used depending on clinical situation and the objectives to be achieved. They can have fixed protection or locked articulation, allow an adjustable range of movement to restrict flexion-extension and pronation-supination, or allow dynamic and static progressive movement. The latter plays a special role in conservative treatment and following surgical release. However, the effectiveness of braces in the rehabilitation treatment of elbow stiffness depends on the patient's compliance. Their use requires a considerable amount of physician time to achieve the objectives envisaged by the rehabilitation program.

Elbow rehabilitation in traumatic pathology

The elbow, intermediate joint of the upper limb, frequently undergoes to pathological events and is especially prone to stiffness. Rehabilitation plays an important role in recovering functional activities. For the rehabilitation team, this goal always represents a challenge, as the treatment has to be continuously modeled and calibrated on the needs of the individual patient, even many times during the same rehabilitation cycle. Containing the effects of immobilization, avoiding to excessively stress the healing tissues, satisfying specific clinical criteria before moving to the next rehabilitation stage, basing the rehabilitation plan on up-to-date clinical and scientific data that can be adapted to each patient and to his/her needs are the basic principles of the rehabilitation plan, which can be chronologically grouped into four rehabilitation stages. After summarizing the general principles of elbow treatment, the specific principles of rehabilitation after elbow fractures and elbow instability are presented, and then the rehabilitative approach to the most frequent and feared pathological conditions of the elbow, namely stiffness, is described.

Temporary presence of myofibroblasts in human elbow capsule after trauma

BACKGROUND

Elbow stiffness is a common complication after elbow trauma. The elbow capsule is often thickened, fibrotic, and contracted at the time of surgical release. The limited studies available suggest that the capsule is contracted because of fibroblast-to-myofibroblast differentiation. We hypothesize that myofibroblasts are absent in normal elbow capsules and in acute trauma and that they are subsequently elevated in patients with posttraumatic elbow contracture.

METHODS

We obtained twenty-one human elbow joint capsules within fourteen days after an elbow fracture and/or dislocation and thirty-four elbow joint capsules in thirty-four patients who had undergone operative release of posttraumatic contractures more than five months after injury. Myofibroblasts in the joint capsules were quantified with use of immunohistochemistry. Alpha-smooth muscle actin was used as a marker for myofibroblasts. Samples were characterized and were scored by an independent pathologist blinded for clinical data.

RESULTS

Eleven capsules were associated with the acute phase after trauma (hours to less than seven days), and staining for alpha-smooth muscle actin was negative in all but one capsule. Ten capsules were associated with a later posttraumatic phase with myofibroblasts staining positive for alpha-smooth muscle actin in all but two capsules. Thirty-two long-standing contractures showed a histological pattern consistent with chronic stages of fibrosis, characterized by increased fibroblast-like cell proliferation and higher cellular density of fibroblast-like cells with highly unstructured collagen. Two joint capsules showed an earlier phase of fibrosis. Only two of the long-standing contractures had staining of alpha-smooth muscle actin in fibroblast-like cells; the lack of staining in the other contractures suggested an absence of myofibroblasts.

CONCLUSIONS

This study presents negative results on the hypothesis that myofibroblast numbers are elevated in long-standing (more than five months) human posttraumatic elbow capsules. The absence of myofibroblasts in long-standing elbow contracture capsules is in contrast to most other studies on human tissue in the literature to date.

Prevention and treatment of elbow stiffness: a 5-year update

Elbow stiffness is a challenging and common problem faced by upper extremity surgeons. Although functional improvements can be made with both nonsurgical and surgical management strategies, physicians must remain vigilant with efforts to prevent stiffness before it starts. Recent advancements in the biology and pathology of elbow contracture have led to improved understanding of this difficult problem, and they may lead to future breakthroughs in the prevention and treatment of elbow stiffness. This article serves as an update to our previous review of elbow stiffness, focusing on recent advancements in the past 5 years, as well as updating our current algorithm for treatment.

Posttraumatic elbow contractures: targeting neuroinflammatory fibrogenic mechanisms

Posttraumatic elbow stiffness remains a common and challenging clinical problem. In the setting of a congruent articular surface, the joint capsule is regarded as the major motion-limiting anatomic structure. The affected joint capsule is characterized by irreversible biomechanical and biochemical fibrogenic changes strikingly similar to those observed in many other fibroproliferative human conditions. Studies in humans and preclinical animal models are providing emergent evidence that neuroinflammatory mechanisms are critical upstream events in the pathogenesis of posttraumatic connective tissue fibrogenesis. Maladaptive recruitment and activation of mast cell infiltrates coupled with the aberrant expression of growth factors such as transforming growth factor-beta, nerve growth factor, and neuropeptides such as substance P are common observations in posttraumatic joint contractures and many other fibroproliferative disorders. Blockade of these factors is providing promising evidence that if treatment is timed correctly, the fibrogenic process can be interrupted or impeded. This review serves to highlight opportunities derived from these recent discoveries across many aberrant fibrogenic disorders as we strive to develop novel, targeted antifibrotic prevention and treatment strategies for posttraumatic elbow stiffness.

Lentivirus-mediated ERK2 siRNA reduces joint capsule fibrosis in a rat model of post-traumatic joint contracture

Extracellular signal-regulated kinase (ERK)-2 is presumed to play an important role in the development of post-traumatic joint contractures. Using a rat injury model, we investigated whether treatment with ERK2 small interfering RNA (siRNA) could reduce the extent of joint capsule fibrosis after an induced injury. Rats were separated into three groups (n = 32 each): non-operated control group, operated contracture group and contracture-treatment group. Stable post-traumatic joint contracture was created through surgical intra-articular joint injury followed by eight weeks of immobilization. In the contracture-treatment group, the rats were treated with lentivirus (LV)-mediated ERK2 siRNA at days 3 and 7 post-surgery. The posterior joint capsule was assessed by western blotting, immunohistochemistry and biochemical analysis for changes in ERK2, phosphorylated (p)-ERK2, myofibroblast, total collagen and relative collagen Type III expression level. Biomechanical testing was used to assess the development of flexion contractures. Statistical analysis was performed using an analysis of variance. In the operated contracture group, rats that developed flexion contractures also showed elevated phosphorylated p-ERK2 expression. In the contracture-treatment group, ERK2 siRNA significantly reduced p-ERK2 expression levels, as well as the severity of flexion contracture development (p < 0.01). Myofibroblast numbers and measurements of total collagen content were also significantly reduced following ERK2 siRNA (p < 0.01). Relative collagen type III expression as a proportion of total of Types I and III collagen, however, was significantly increased in response to ERK2 siRNA (p < 0.01). Our findings demonstrate a role for ERK2 in the induction of joint capsule fibrosis after injury. Furthermore, we show that development of flexion contractures and the resultant increase of joint capsule fibrosis can be reduced by LV-mediated ERK2 siRNA treatment.

Effectiveness of bracing in the treatment of nonosseous restriction of elbow mobility: a systematic review and meta-analysis of 13 studies

BACKGROUND

Restriction of elbow mobility is a very frequent complaint after trauma or surgery. The objective of this study was to assess and compare the effectiveness of dynamic, static, or static-progressive bracing in patients with elbow stiffness of traumatic or postoperative origin and without evidence of ossification. For the purpose of this study, effectiveness was measured as the increase in total range of motion, as well as extension and flexion.

MATERIALS AND METHODS

We performed a systematic search of the keywords "elbow AND (stiffness OR stiff) AND (brace OR splint OR conservative)" in the online databases PubMed, EMBASE, CINAHL (Cumulative Index to Nursing and Allied Health Literature), and the Cochrane Library. We included all clinical studies using dynamic or static bracing in patients with elbow stiffness. Eligible outcomes were changes in total range of motion, flexion, and extension; sustainability of results; and complications.

RESULTS

We included 13 eligible studies, providing data on 14 treated groups in 247 patients. The mean age of these patients was 34.5 ± 10.4 years, and female patients comprised 46% ± 12%. The mean duration from the incident to the start of brace treatment was 6.9 ± 5.1 months. The mean improvement in range of motion during the course of treatment was 38.4° ± 8.9° (95% confidence interval, 39.5°-41.8°).

CONCLUSIONS

The current evidence strongly supports the use of static-progressive stretching 3 times 30 minutes per day in each direction as a first line of treatment in patients with post-traumatic and postsurgical elbow stiffness. If this treatment fails or if reasons for stiffness other than soft-tissue incompliance are identified, further surgical interventions should be considered.

Posttraumatic elbow stiffness

Early posttraumatic elbow contractures may be treated with a combination of manipulation with the patient under anesthesia followed by bracing.Extrinsic contractures of the elbow may be treated with open or arthroscopic release, whereas intrinsic and combined contractures may require tissue release as well as partial or total arthroplasty.

The mast cell stabilizer ketotifen reduces joint capsule fibrosis in a rabbit model of post-traumatic joint contractures

OBJECTIVES

Using a rabbit model of post-traumatic joint contractures, we investigated whether treatment with a mast cell stabilizer after joint injury would lessen the molecular manifestations of joint capsule fibrosis.

METHODS

Surgical joint injury was used to create stable post-traumatic contractures of the knee in skeletally mature New Zealand white rabbits. Four groups of animals were studied: a non-operated control group (n = 8), an operated contracture group (n = 13) and two operated groups treated with the mast cell stabilizer, ketotifen, at doses of 0.5 mg/kg (n = 9) and 1.0 mg/kg (n = 9) twice daily. Joint capsule fibrosis was assessed by quantifying the mRNA and protein levels of α-SMA, tryptase, TGF-β1, collagen I and collagen III. Significance was tested using an ANOVA analysis of variance.

RESULTS

The protein and mRNA levels of α-SMA, TGF-β1, tryptase and collagen I and III were significantly elevated in the operated contracture group compared to control (p < 0.01). In both ketotifen-treated groups, protein and mRNA levels of α-SMA, TGF-β1 and collagen I were significantly reduced compared to the operated contracture group (p < 0.01).

CONCLUSIONS

These data suggest an inflammatory pathway mediated by mast cell activation is involved in joint capsule fibrosis after traumatic injury.

The mast cell stabilizer ketotifen fumarate lessens contracture severity and myofibroblast hyperplasia: a study of a rabbit model of posttraumatic joint contractures

BACKGROUND

The propensity of joints to become stiff after trauma is widely appreciated, and the joint capsule is commonly recognized as the major motion-limiting anatomical structure. Affected joint capsules become fibrotic, characterized by myofibroblast and collagen hyperplasia. Mast cell hyperplasia is common within fibrotic tissue, and mast cells are known to synthesize many profibrotic mediators. We hypothesized that mast cell inhibition after skeletal injury would lessen contracture severity and reduce myofibroblast hyperplasia within the joint capsule.

METHODS

Posttraumatic contractures of the knee were created with use of a combination of intra-articular injury and internal immobilization in skeletally mature New Zealand White rabbits. Four groups of animals were studied: a nonoperative control group, a group with the operatively created contracture and no pharmacological treatment (the operative contracture group), and two groups with the operatively created contracture that were treated with a mast cell stabilizer, ketotifen fumarate, at a dose of either 0.5 or 1.0 mg/kg twice daily (the 0.5-mg/kg and 1.0-mg/kg ketotifen groups). After eight weeks of immobilization, flexion contractures were measured and the posterior aspect of the joint capsule was harvested for quantification of myofibroblast and mast cell numbers.

RESULTS

Flexion contractures developed in the operative contracture group (mean and standard deviation, 58 degrees +/- 14 degrees ), and the severity of the contractures was reduced in both the group treated with 0.5 mg/kg of ketotifen (42 degrees +/- 17 degrees ) and the group treated with 1.0 mg/kg of ketotifen (45 degrees +/- 10 degrees ) (p < 0.02). The joint capsule myofibroblast and mast cell numbers in the operative contracture group were significantly increased compared with the values in the control group (p < 0.001), and the myofibroblast and mast cell numbers in both ketotifen groups were significantly reduced compared with the values in the operative contracture group (p < 0.001).

CONCLUSIONS

The use of a mast cell stabilizer, ketotifen, was effective in reducing the biomechanical and cellular manifestations of joint capsule fibrosis in a rabbit model of posttraumatic joint contracture. This finding suggests that an inflammatory pathway, mediated by mast cell activation, is involved in the induction of joint capsule fibrosis after traumatic injury.

Complications related to simple dislocations of the elbow

Simple elbow dislocations may present complications that are anything but simple. Although occurring less frequently, these complications are identical to those associated with more complex fracture-dislocations: contracture, heterotopic ossification, Essex-Lopresti injury, neurovascular injury, and residual instability. Each complication is discussed, including strategies for prevention, evaluation, and treatment.