Arthrographic description of the canine carpal joint cavities and its recesses

Joint effusion is diagnostically important. The canine carpal joint effusion, which is sometimes difficult to detect clinically, has received less attention in diagnostic ultrasound (US) studies. The aim of the present study was to provide a description of the morphological appearance of the canine carpal joint cavities and recesses using US, radiography, helical computed tomography (CT) and three-dimensional volume rendering technique (3D-VRT) images and to prove the applicability of musculoskeletal US for the detection of artificial carpal joint effusion in dogs. The understanding of the characteristics of these structures in normal patients is essential in the diagnosis. Twenty-eight clinically and radiologically unremarkable canine carpal cadavers of different breeds were examined, representative images were selected and anatomical structures were labelled. The canine carpal joint cavities and in particular its recesses had a complex appearance with a basic structure found in all dogs: Antebrachiocarpal joint: dorsoproximal antebrachiocarpal recess, dorsodistal antebrachiocarpal recess, medial antebrachiocarpal recess, lateral antebrachiocarpal recess and five palmar antebrachiocarpal recesses. Middle carpal joint: two dorsal middle carpal recesses, medial common middle carpal and carpometacarpal recess, lateral common middle carpal and carpometacarpal recess, four palmar middle carpal recesses. The carpometacarpal joint had dorsal and palmar funnel-shaped and irregular, finely tubular extensions, the most prominent ran dorsal to metacarpal III, the maximum distal end represented the proximal metacarpal diaphysis. All recesses presented ultrasonographically as a generalized anechogenic to hypoechoic filled continuation of the articular capsule with an indistinct peripheral hypoechogenic to isoechogenic fine capsule, the synovial-connective tissue interface was difficult to identify. The novel results of this study provide the first morphological description of the ultrasonographic, radiographic and computed tomographic arthrographic appearance of the canine carpal joint cavities and recesses with different injection volumes. The canine carpal joint cavities and in particular its recesses had a complex appearance with a basic structure found in all dogs. The applicability of musculoskeletal US to visualize an artificial carpal effusion has been demonstrated. The results of this study, and in particular US, give the practitioner an advantage in visualizing joint effusion and assist in the decision to perform arthrocentesis.

A new injection method for identifying the subpopliteal recess of the knee

The posterolateral region of the knee has a complex and diverse anatomy. Hydrarthrosis of the knee can potentially communicate with other parts of the joint space. The joint fluid distribution reflects anatomical communications between synovial spaces. To observe the continuity between the knee joint cavity and the surrounding bursa, we devised a dissection method with a new injection agent, an eosin-containing congealed liquid that spreads uniformly over the entire space. The purpose of this study was to perform a detailed examination of the subpopliteal recess (SPR) where a bursa connects to the knee joint capsule. We also reported the advantages of this new injection agent compared with conventional materials (latex and epoxy resin). Twenty-two formalin-fixed cadavers (34 knees), two N-vinyl-pyrrolidone (NVP)-fixed cadavers (4 knees), and two cadavers (3 knees) fixed by Thiel's method were used. After filling the knee joint space and SPR with eosin congealed liquid, the specimens were dissected to investigate the morphology of the SPR. In addition, three different types of injection agents were assessed. The SPR extended distally along the popliteus tendon. The SPR length was 22.64 ± 11.38 mm from the upper end of the lateral tibial condyle to the lower end of the depression. The existence of a fabellofibular ligament made the SPR significantly longer, but abrasion of the femoral articular cartilage did not affect the SPR. Furthermore, the relationship between the popliteus muscle and the SPR was classified into three types (types 1-3). Types 2 and 3 in which the SPR extended to the proximal tibiofibular joint may cause instability of the knee joint. The eosin congealed liquid was highly useful in many aspects, such as fluidity and injection workability. The new dissection method with eosin congealed liquid provides insights into the anatomy of the posterior lateral knee, which are useful for radiological diagnoses and clinical treatments.

Preliminary investigation on the effect of extracorporeal shock wave combined with traction on joint contracture based on PTEN-PI3K/AKT pathway

To investigate the intervention effect of extracorporeal shock wave combined with manual traction on fixation-induced knee contracture and its influence on PTEN-PI3K/AKT signaling pathway. Thirty-six SD male rats were randomly divided into six groups. The left knee joints were not fixed in the control group (C group). Rats in other groups underwent brace fixation in the extended position of the left knee. After 4 weeks of bracing, it is randomly divided into five groups: Model group (M group), natural recovery group (NR group), extracorporeal shock wave treatment group (ET group), manual traction group (MT group), and extracorporeal shock wave combined with manual traction group (CT group). Joint range of motion (ROM) of left knee was carried out to assess joint function. Hematoxylin and eosin (HE) staining and Masson staining were respectively used to assess the cell number and collagen deposition expression. Immunohistochemical staining and Western blot were used to assess protein levels of phosphatase and tensin homolog (PTEN), phosphatidylinositol 3-kinase (PI3K), and protein kinase B (AKT). The combined therapy was more effective than extracorporeal shock wave therapy or manual traction alone against the joint ROM, cell number and the collagen deposition, low-expression of PTEN, and overexpression of PI3K/AKT in the anterior joint capsule of rats with knee extension contracture. Extracorporeal shock wave combined with manual traction can promote the histopathological changes of anterior joint capsule fibrosis, upregulate the protein expression of PTEN and downregulate the protein expression of PI3K/AKT in the fibrotic joint capsule in a rat joint contracture model.

Catastrophic Mid-Flexion Instability After Avulsion Fractures of the Articular Capsule of the Femur and Tibia in a Patient With Posterior-Stabilized Total Knee Arthroplasty: A Case Report

Mid-flexion instability can be caused by patient-related, implant-related, or technique-specific factors and impairs the activities of daily living after total knee arthroplasty (TKA). In this study, we report a rare case of a patient with severe mid-flexion instability following tibial and femoral avulsion fractures after posterior-stabilized (PS) TKA for knee osteoarthritis. An 82-year-old female with bilateral knee osteoarthritis underwent staged bilateral TKA with a posterior-stabilized prosthesis. The course of the early postoperative period was good, and the patient was able to walk independently with a cane. Two months postoperatively, the patient fell and then experienced left knee pain and instability in the mid-flexion range. Radiographic images showed avulsion fractures of the articular capsule of the femur and tibia, and fluoroscopic examination showed severe posterior subluxation of the tibia between 40° and 60° of flexion. Conservative treatment with a functional knee brace and quadriceps training was initiated due to the patient's hesitation to undergo a second surgery; however, no improvement was observed. Eventually, revision surgery was planned three months after the fall incident (five months after the left primary TKA). At revision surgery, osteosynthesis of the tibial avulsion fracture and thickening of the PS insert did not sufficiently stabilize the instability, and revision TKA with a rotating-hinge prosthesis was needed. The postoperative course was uneventful, and she was able to walk with a cane within two weeks after revision TKA with no complaints of instability. Two years postoperatively, the patient recovered well and had no recurrence of instability, pain, or dysfunction. This case report shows that loss of support by the joint capsules due to avulsion fractures may cause significant anteroposterior instability in the mid-flexion position after posterior-stabilized TKA. In such a case, conservative treatment failed, and the revision of the rotating-hinge prosthesis provided stability and good improvement.

Extracorporeal shockwave therapy in an immobilized knee model in rats prevents progression of joint contracture

Joint immobilization, which ensures rest and accelerates tissue recovery in musculoskeletal disorders, often causes joint contracture, for which there is still no effective prevention. To address this, we investigated the effects of extracorporeal shockwave therapy (ESWT) in preventing joint contracture, in a unilaterally immobilized knee rat model. Under general anesthesia, ESWT (0.25 mJ/mm² , 3000 shot, 4 Hz, 3 days/week) was administered from 1 day after immobilization up to 2, 4, and 6 weeks. The immobilized control group received general anesthesia without ESWT. We evaluated joint angle, tissue elasticity, and gene and protein expression related to fibrosis, inflammation, and angiogenesis in the joint capsule. Relative to the control, the ESWT group had greater joint angle at 4 and 6 weeks, and lower posterior-capsule elasticity at 6 weeks. In the ESWT group, at 6 weeks, gene expression of collagen type I (col1α1), connective tissue growth factor (CTGF), and α-smooth muscle actin (α-SMA) was significantly downregulated, whereas interleukin-6 (IL-6) and hypoxia-inducible factor-1α (HIF-1α) gene expression was upregulated, relative to that in the control. Compared with that in the control, at 4 and 6 weeks, the ratio of CTGF⁺ cells was significantly lower in the ESWT group; at 4 weeks, the ESWT group had significantly fewer CD68⁺ cells in the adhesion area, and at 6 weeks, significantly more blood vessels. Statement of Clinical Significance: In a rat model, ESWT counteracted fibrosis, suppressed macrophage infiltration, and promoted neovascularization, reducing elasticity, and increasing joint range-ofmotion. ESWT offers a potential new strategy to prevent progression in joint contracture.

Development of a novel knee contracture mouse model by immobilization using external fixation

AIMS

Several studies have used animal models to examine knee joint contracture; however, few reports detail the construction process of a knee joint contracture model in a mouse. The use of mouse models is beneficial, as genetically modified mice can be used to investigate the pathogenesis of joint contracture. Compared to others, mouse models are associated with a lower cost to evaluate therapeutic effects. Here, we describe a novel knee contracture mouse model by immobilization using external fixation.

METHODS

The knee joints of mice were immobilized by external fixation using a splint and tape. The passive extension range of motion (ROM), histological and immunohistochemical changes, and expression levels of fibrosis-related genes at 2 and 4 weeks were compared between the immobilized (Im group) and non-immobilized (Non-Im group) groups.

RESULTS

The extension ROM at 4 weeks was significantly lower in the Im group than in the Non-Im group (p < 0.01). At 2 and 4 weeks, the thickness and area of the joint capsule were significantly greater in the Im group than in the Non-Im group (p < 0.01 in all cases). At 2 weeks, the mRNA expression levels of the fibrosis-related genes, except for the transforming growth factor-β1, and the protein levels of cellular communication network factor 2 and vimentin in the joint capsule were significantly higher in the Im group (p < 0.01 in all cases).

CONCLUSION

This mouse model may serve as a useful tool to investigate the etiology of joint contracture and establish new treatment methods.

Effect of diabetes and corticosteroid injection on glenohumeral joint capsule in a rat stiffness model

PURPOSE

To evaluate the effects of diabetes and corticosteroid injected in the joints on the shoulder motion, gait, and joint capsular properties in a rat stiffness model.

METHODS

A total of 27 rats were randomly distributed into 3 groups-nondiabetes group (group A), diabetes group (group B), and diabetes plus steroid injection group (group C). The diabetes model was developed by inducing hyperglycemia with a submaximal dose of streptozotocin and the stiffness model by completely immobilizing the right shoulder of each animal in all groups with sutures passed between the scapula and humeral shaft. The left shoulder was used as an untreated control in all groups. Three weeks after immobilization, the sutures were removed in all groups, and a single dose of triamcinolone acetonide (0.5 mg/kg) was injected into the glenohumeral joint in group C. After 3 weeks of free activity, range of motion (ROM) evaluation, gait analysis by stride length, and capsular area measurement were performed in all rats.

RESULTS

Hyperglycemia was successfully induced with a mean blood glucose level of 448.9±55.9 mg/dL in group B and 431.6±17.8 mg/dL in group C, which were significantly higher than 136.5±13.4 mg/dL in group A (P < .001). A significantly smaller ROM and stride length were found in the right (stiffness-induced) shoulder than that in the left (control) shoulder only in group B, and significantly larger capsular area in the right shoulder than that in the left shoulder in groups A and B (all P < .05). However, in group C, there were no differences between the right and left shoulders in all measurements (all P > .05). In case of the right shoulders in each group, group C showed significantly larger ROM (68° ± 11° vs. 42° ± 7°) and smaller capsular area (3934.4 ± 537.1 pixels vs. 7402.3 ± 1840.3 pixels) than group B (all P < .0167).

CONCLUSIONS

The diabetic model had a detrimental effect on the development of stiffness by thickening the joint capsule, and an intra-articular steroid injection resolved the thickened joint capsule and restored shoulder motion.

Dynamic changes of the joint capsule in relation to the zona orbicularis: An anatomical study with possible implications for hip stability mechanism

The zona orbicularis, which comprises the inner circular fibers of the joint capsule, is vital for hip stability in distraction. Despite the proximity of the whole joint capsule to the zona orbicularis, their anatomical relationship remains unclear. The aim of this study is to investigate the characteristics of the inner side of the joint capsule comprehensively. Twelve hips from nine bodies donated to science were examined. Six and three of the donated bodies, respectively, were embalmed using 8% formalin and Thiel's method. The joint capsules in three formalin‐embalmed bodies were sturied by micro‐computed tomography. During formalin fixation of six hips from these three bodies, one side was maintained at hip extension and the other at flexion. The remaining three formalin‐embalmed bodies were examined histologically. Micro‐computed tomography images revealed that the inward protrusion of the joint capsule narrowed the articular cavity, and the ratio of its narrowest area to that of the femoral neck was less at hip extension than at hip flexion. The Thiel's method specimens showed that the inner surface of the joint capsule protruded inward toward the femoral neck during hip extension. This inward protrusion was not histologically independent of the joint capsule. The zona orbicularis was interpreted as the inward protrusion caused by dynamic change of the joint capsule, rather than the local collar. In other words, the joint capsule could change its morphology dynamically depending on the hip position.

Histopathological Evaluation of Mechanoreceptors in the Metatarsophalangeal Joint Capsule in Hallux Valgus

To date, we could find no study concerning the relationship between mechanoreceptors in the joint capsule of the first metatarsophalangeal joint and hallux valgus deformity. We aimed to investigate the presence of mechanoreceptors in samples obtained from the first metatarsophalangeal joint capsules of patients with hallux valgus deformity to improve our understanding of the clinical and histopathological features of the disease. Samples were taken from the first metatarsophalangeal joint capsules of 13 fresh-frozen cadavers with normal anatomy (controls) and 29 patients undergoing surgery for hallux valgus (cases). For light microscopy, excised specimens were fixed in 10% formaldehyde and processed for routine histopathological investigation. All samples were dehydrated in a series of ethanol, cleared in xylene, and embedded in paraffin. Orientation of collagen fibers was determined on Masson's trichrome-stained sections, and mechanoreceptors were evaluated on S-100-immunostained sections. In the sections stained with Masson's trichrome, the orientation of collagen fibers was regular in the control group. However, coarse and disoriented collagen bundles were observed in the hallux valgus cases (P ≤ .05). S-100 immunostaining was positive in the sections of both the cases and controls. Finally, free nerve endings were more abundant in the samples obtained from the capsules of hallux valgus cases than from the control group (P ≤ .05). An increase in the number of free nerve endings within the capsules of the first metatarsophalangeal joints in feet with hallux valgus deformity might have a role in the development of clinically relevant joint pain and instability.

Location and magnitude of capsular injuries varies following multiple anterior dislocations of the shoulder: Implications for surgical repair

Capsular injuries can occur during multiple shoulder dislocations. The purpose of this study is to evaluate the location and magnitude of glenohumeral capsular injury following multiple dislocations. We hypothesized that the magnitude of capsular injury would increase and the location of peak injury would vary depending on the number of dislocations. Seven fresh-frozen cadaveric shoulders were used. A 7 × 11 grid of strain markers was affixed to the anteroinferior capsule. Each joint was then mounted to a six degree-freedom robotic testing system. Marker tracking was performed following 1, 2, 3, 4, 5, and 10 dislocations to determine the nonrecoverable strain as capsular injury. Following each dislocation, the magnitude of the maximum principal strain representing the nonrecoverable strain in the inferior glenohumeral capsule was quantified by comparing the strain marker positions following each dislocation. The peak value of nonrecoverable strain statistically increased with the number of dislocations in five of seven specimens (p = .0007). The capsular location that had the peak value of nonrecoverable strain varied according to the number of dislocations, and from specimen to specimen. The nonrecoverable strain was identified in the posterior capsule and anterior axillary pouch, which increased with the number of dislocations compared to the other regions of the capsule (p = .001-.012) by up to 16%. Clinical significance: While plication of the anterior axillary pouch is important following multiple dislocations, a more extensive anterior capsular shift may be necessary with an increased number of dislocations in addition to a posterior capsular shift when appropriate.

[Effectiveness of peri-articular infiltration with local anesthetic and adjuvants for post-surgical pain control in total knee replacement]

INTRODUCTION

Total knee arthroplasty (TKA) is one of the most successful orthopedic treatments, however, it has been associated with severe postsurgical pain in 30-60% of patients. We propose that infiltration of the articular capsule of the knee during surgery will decrease postsurgical pain.

MATERIAL AND METHODS

Experimental, randomized, double-blind study in patients undergoing unilateral TKA between April 2018 and January 2019. Patients were divided into two groups, the first infiltration with placebo and the second with anesthetic solution and adjuvants (fentanyl, epinephrine and ketorolac). Pain was measured with the visual analog scale (VAS) at 4, 6, 8, 12, 18, 24, 36 and 48 hours postsurgical, as well as the consumption of opioid analgesics and antiemetics.

RESULTS

20 patients in each group, with a follow-up of 4 weeks. There were no significant differences in demographic characteristics between the two groups. Better control of postsurgical pain was observed in the group that received infiltration with anesthetic and adjuvant, as well as a decrease in the consumption of opioid analgesics and antiemetics. There was no difference in bleeding or in the incidence of infections between the two groups.

CONCLUSION

Peri-capsular infiltration is a safe and effective method, as part of multimodal analgesia in total knee arthroplasty, as it decreases postsurgical pain, opioid and antiemetic use and does not increase postsurgical bleeding.

Clinical outcomes of arthroscopic pan-capsular release with or without entire coracohumeral ligament release for patients with frozen shoulder

Background

We aimed to retrospectively determine the effects of arthroscopic pan-capsular release with or without entire coracohumeral ligament (CHL) release and diabetes mellitus (DM) in patients with frozen shoulder (FS).

Methods

The study included 34 patients (20 male and 14 female patients) who underwent arthroscopic pan-capsular release without entire CHL release (group 1) and 26 patients (6 male and 20 female patients) who underwent entire CHL release for FS (group 2). Patients with a minimum of 12 months of follow-up were included, and range of motion (ROM) and the shoulder rating scale of the University of California at Los Angeles (UCLA) scoring system were evaluated.

Results

In group 2, external rotation and hand-behind-the-back (HBB) ROMs were significantly increased compared with group 1 at the final follow-up (external rotation, 53.1° ± 15.2° vs. 41.3° ± 20.5° [P = .044]; HBB level, T6 [interquartile range, T5-T9] vs. T11 [interquartile range, T8-L4] [P < .001]). Total UCLA scores and UCLA scores for pain (9.2 ± 1.5 vs. 10.0, P = .003), function (8.5 ± 1.4 vs. 10.0, P < .001), and active forward flexion (4.6 ± 0.6 vs. 4.9 ± 0.2, P < .011) were significantly greater in group 2 at the final follow-up. Patients without DM tended to have greater recovery of forward flexion and HBB ROMs and better total, pain, and function UCLA scores compared with those with DM. In group 2, there were no significant differences in ROMs and UCLA scores between the patients with DM and those without DM.

Conclusion

Arthroscopic entire CHL release is an essential treatment option for FS patients to regain ROMs and function and to reduce pain.

Effects of joint capsular release on range of motion in patients with frozen shoulder

BACKGROUND

A thickened joint capsule is believed to be one of the most specific manifestations of and the primary restraint against range of motion (ROM) in frozen shoulders. The purpose of this study was to evaluate the relationship among ROMs under general anesthesia before surgery and the effects of each joint capsular release on ROM.

METHODS

ROM was measured using a goniometer with scapular fixation. Arthroscopic pan-capsular release was performed with the patient in the beach-chair position in the following order: (1) rotator interval, (2) coracohumeral ligament, (3) superior capsule, (4) middle glenohumeral ligament, (5) anterior inferior glenohumeral ligament, and (6) posterior inferior glenohumeral ligament. ROMs in forward flexion (FF), lateral elevation (LE), external rotation with the arm at the side (ER1), external rotation at 90° of LE (ER2), internal rotation at 90° of LE (IR2), horizontal flexion, external rotation at 90° of FF (ER3), and internal rotation at 90° of FF (IR3) were evaluated before and after each release.

RESULTS

A total of 32 consecutive shoulders were included. After each capsular release, the ROM recovered; the final ROM was significantly greater on the affected side than on the unaffected side. Significant correlations were found between FF and LE, FF and ER1, ER1 and ER2, ER1 and ER3, ER2 and ER3, and IR2 and IR3 on both sides, regardless of surgery.

CONCLUSION

Each segment of the joint capsule affected ROM in all directions, supporting the need for whole-joint capsular release; ROM was significantly greater on the affected side than on the unaffected side after surgery.

MRI Findings Predictive of Shoulder Stiffness in Patients With Full-Thickness Rotator Cuff Tears

OBJECTIVE. The objective of our study was to evaluate the relationship between stiff shoulder in patients with a full-thickness rotator cuff tear and MRI findings, especially joint capsule abnormality. MATERIALS AND METHODS. This study included 106 patients with small to large (≤ 5 cm) full-thickness rotator cuff tears. Joint capsule edema and thickness in the axillary recess, obliteration of the subcoracoid fat triangle, fatty degeneration of the torn rotator cuff muscle, and degree of retraction were assessed by two radiologists. The size and location of tears were determined by MRI findings and operative report. Associations between MRI findings and preoperative passive range of motion (ROM) were assessed by simple and multiple linear regression analyses and proportional odds logistic regression analysis. RESULTS. There was a significant, negative linear correlation between limited ROM at forward elevation and thickness of the joint capsule in the glenoid portion of the axillary recess (p = 0.018), external rotation and joint capsule edema in the humeral portion of the axillary recess (p = 0.011), and internal rotation and joint capsule edema in the glenoid portion of the axillary recess (p = 0.007). Male sex (p = 0.041) and posterosuperior rotator cuff tear (p = 0.030) were independent predictors of shoulder ROM on external rotation. Degree of fatty degeneration (p = 0.003) was another independent predictor of shoulder ROM on internal rotation. CONCLUSION. MRI findings-especially joint capsule edema and thickness at the axillary recess-can be useful in predicting shoulder stiffness in patients with rotator cuff tear.

Features of the Femoral Proximocaudal Joint Capsule Insertion Among Canids

This observational study was conducted to evaluate the anatomic relationship between the proximocaudal femoral joint capsule insertion and the femoral caudolateral curvilinear osteophyte (CCO), across ancient and modern domestic and non-domestic canids. Museum specimens of proximal femora were screened for presence of remnant enthesophytes of the caudal joint capsule insertion (first inclusion criterion) and then for the CCO (second inclusion criterion). The initially screened population included 267 dry bone specimens: Six Canis species, hybrid coyote × domestic dog, and five vulpines (three Vulpes species, one Urocyon, and one Nyctereutes). Proximocaudal joint capsule insertion remnant enthesophytes were limiting at n = 19 specimens: Seven ancient domestic dogs, four modern coyotes, two ancient coyotes, two modern hybrid coyote × dog, two modern red foxes, and two modern raccoon dogs. The joint capsule enthesophytes are associated with inflammation, but are observed far less frequently than the CCO. The CCO is seen radiographically but is visible more frequently by direct inspection. The primary inclusion criterion necessarily was a visible caudal joint capsule insertion; spatial relationships of the CCO can be assigned with confidence only when a capsule insertion line can be recognized clearly. We demonstrate that the anatomic CCO associates with the joint capsule insertion being nonspecific and species-independent. A joint capsule insertion-CCO spatial relationship across species is an important new observation, strongly indicating that both are pathological features. Our data indicate need for new research to characterize the canid coxofemoral joint and its overt and incipient pathology in a phylogenetic context. Anat Rec, 302:2164-2170, 2019. © 2019 American Association for Anatomy.

Comparative proteome analysis of the capsule from patients with frozen shoulder

BACKGROUND

The etiology of frozen shoulder (FS) is unclear. Accordingly, this study used a label-free quantitative shotgun proteomic approach to elucidate the pathogenesis of FS based on protein expression levels.

METHODS

Tissue samples from the rotator interval (RI), middle glenohumeral ligament (MGHL), and anterior-inferior glenohumeral ligament (IGHL) were collected from 12 FSs with severe stiffness and 7 shoulders with a rotator cuff tear (RCT) as controls. Protein mixtures were digested and analyzed by nano-liquid chromatography/electrospray ionization-tandem mass spectrometry. Relative protein expression levels were calculated by the signal intensity of identified peptide ions on mass spectra. Differentially expressed proteins between FS and RCT samples were evaluated by a gene enrichment analysis using Gene Ontology and Kyoto Encyclopedia of Genes and Genomes.

RESULTS

We identified 1594 proteins, 1358 of which were expressed in all 6 tissue groups. We detected more upregulated proteins in the upper (RI and MGHL) FS groups and the lower (IGHL) RCT group than in the comparative groups, respectively. Various proteins with functions in tissue repair, collagen metabolism and fibrillation, cell-cell and cell-matrix adhesion, blood coagulation, and the immune response were expressed more highly in the RI and MGHL FS groups than in the RCT group. Proteins with functions in phagocytosis, glutathione metabolism, retinoid metabolism, and cholesterol metabolism were expressed more highly in the IGHL RCT group than in the FS group.

CONCLUSIONS

The pathophysiology of FS differs between the upper and lower parts of the joint capsule. Different treatment strategies for FS may be appropriate, depending on the location.

Novel rabbit model of moderate knee contracture induced by direct capsular damage

The treatment of joint contracture continues to represent a challenging problem in orthopedic surgery and rehabilitation medicine. Existing animal models of knee contracture for evaluating new treatments are mostly created by extensive joint tissue damage with Kirschner-wire immobilization which requires a second surgery to remove Kirschner-wires. This study aimed to develop a less invasive rabbit model of moderate knee contracture through a single surgery. Skeletally mature New Zealand White rabbits had their right knee operated to create surgical damage to the posterior capsule under direct visualization. Operated knees were then held in a flexed position by suturing the superficial flexion muscles with absorbable sutures. The flexion contracture (net extension loss) was determined by comparing the extension angles between the operated and non-operated knees from 8 to 24 weeks post-surgery. The flexion contracture of the operated knees was significantly greater (p < 0.01/0.001) than the non-operated knees at each weekly measurement. The mean flexion contractures were 22° at 8 weeks, 19° at 16 weeks, and 18° at 24 weeks. No significant differences in the severity of flexion contracture were observed between 8-week and each of the following weeks, suggesting that the flexion contracture was essentially stabilized by 8 weeks post-surgery. Histopathologic analyses demonstrated intra-articular and peri-articular scar formation. This less invasive rabbit model of moderate knee contracture is more quickly established through a single surgery with lower risk of surgical complications compared to the previously reported invasive models, and could be an alternative animal model for joint contracture research. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:2687-2695, 2018.

Cytokine Interferon-γ suppresses the function of capsule myofibroblasts and induces cell apoptosis

Myofibroblasts (MFs), a contractile subset of fibroblasts, play a pivotal role in physiological wound healing and in the development of many fibroconnective disorders. The complex cytokine network regulating the function of MFs in joint stiffness is still poorly understood. In this in vitro study, we investigated the effect of the cytokine Interferon-gamma (IFN-γ) on MFs isolated from human joint capsules. MFs were cultivated either in the presence of increasing concentrations of IFN-γ alone or in combination with IFN-γ neutralizing antibodies. Cell viability, cytotoxicity, apoptosis, and mRNA gene expression of the MF markers alpha-smooth muscle actin (α-SMA) and collagen type I were analyzed in MF cultures. Contraction potential was analyzed in an established collagen gel contraction assay simulating the extracellular matrix. Using immunofluorescence staining, we could verify that MFs express IFN-γ-receptor (R)-1 on their membrane. IFN-γ decreased MF viability and significantly elevated the apoptosis rate in a dose-dependent manner. IFN-γ down-regulated α-SMA and collagen type I mRNA expression which was associated with a diminished MF mediated contraction of the gel matrices. These effects were suppressed by simultaneous treatment of cells with a neutralizing IFN-γ antibody. Our experiments confirm the hypothesis that the cytokine IFN-γ is a crucial component of the regulatory network of capsule MFs. IFN-γ notably influences the ability of MFs to contract collagen matrices by suppressing α-SMA gene expression. IFN-γ is toxic for MFs in high concentrations and may negatively regulate the number of pro-fibrotic MFs during the healing process via induction of cell apoptosis. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:2524-2533, 2017.

Effects of joint immobilization on changes in myofibroblasts and collagen in the rat knee contracture model

The purpose of this study was to examine the time-dependent changes in the development of joint capsule fibrosis and in the number of myofibroblasts in the joint capsule after immobilization, using a rat knee contracture model. Both knee joints were fixed in full flexion for 1, 2, and 4 weeks (immobilization group). Untreated rats were bred for each immobilization period (control group). Histological analysis was performed to evaluate changes in the amount and density of collagen in the joint capsule. The changes in type I and III collagen mRNA were examined by in situ hybridization. The number of myofibroblasts in the joint capsule was assessed by immunohistochemical methods. In the immobilization group, the amount of collagen increased within 1 week and the density of collagen increased within 2 weeks, as compared with that in the control group. Type I collagen mRNA-positive cell numbers in the immobilization group increased at all time points. However, type III collagen mRNA-positive cell numbers did not increase. Myofibroblasts in the immobilization group significantly increased compared with those in the control group at all time points, and they increased significantly with the period of immobilization. These results suggest that joint capsule fibrosis with overexpression of type I collagen occurs and progresses within 1 week after immobilization, and an increase in myofibroblasts is related to the mechanism of joint capsule fibrosis. The findings suggest the need for a treatment targeting accumulation of type I collagen associated with an increase in myofibroblasts. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:1998-2006, 2017.

Joint capsule attachment to the coronoid process of the ulna: an anatomic study with implications regarding the type 1 fractures of the coronoid process of the O'Driscoll classification

BACKGROUND

The attachment of the anterior joint capsule on the ulnar coronoid process is not yet completely understood. The purpose of this study was to clarify the anatomic relationship between the anterior capsule of the elbow joint and the tip of the coronoid process.

METHODS

Seventeen embalmed elbows were used for this anatomic study. The anterior capsule of the elbow joint was reflected, and the attachment of the capsule on the coronoid process was exposed. The attachment of the joint capsule on the coronoid process was macroscopically and histologically observed, its relationship to the coronoid tip was assessed, and the length of the attachment of the joint capsule was measured.

RESULTS

The length of the capsule attachment at the radial side of the coronoid (11.9 mm) was greater than that at the ulnar side (6.1 mm). The bone thickness on the coronoid tip from the proximal edge of the joint capsule attachment was 1.9 mm; together, the cartilage and bone thickness was 4.7 mm. At the radial side of the coronoid, the thickness of the joint capsule at the proximal aspect of the attachment of 2 samples was 0.6 mm and 0.3 mm, and that at the tip of the coronoid was 2.6 mm and 1.7 mm, respectively.

CONCLUSIONS

The anterior capsule of the elbow joint had a substantial attachment on the radial side of the coronoid process. The subtype 2 tip fractures of the O'Driscoll classification included the joint capsule attachment, joint cartilage, and subchondral bone.

Blebbistatin-Loaded Poly(d,l-lactide-co-glycolide) Particles For Treating Arthrofibrosis

Joint immobility is a debilitating complication of articular trauma that is characterized by thickening and stiffening of the joint capsule and the formation of fibrotic lesions inside joints. Capsule release surgery can temporarily restore mobility, but contraction often recurs due to the contractile activities of fibroblasts, which exert tension on the capsule ECM via nonmuscle myosin II. Based on these findings we hypothesized that blebbistatin, a drug that reversibly inhibits the activity of this protein, would relax ECM tension imposed by fibroblasts and reduce fibrosis. In this study, we characterized the effectiveness of blebbistatin as an anticontractile treatment. Given that sustained suppression of contractile activity may be required to achieve capsule release and reduce fibrosis, we compared the effects on fibroblast-mediated collagen ECM displacement of blebbistatin-loaded poly(lactide-co-gylcolide) (PLGA) particles versus bolus blebbistatin dosing. Time-lapse imaging of fluorescent microspheres embedded in collagen gels confirmed that PLGA/blebbistatin inhibited force generation and reduced both gel displacement and rate of displacement. In addition, collagen production at 10 days was significantly reduced. Taken together, these data indicate that blebbistatin-loaded PLGA particles can be used to inhibit fibroblast force-generation and reduce collagen production and lay the foundation for optimization of drug delivery technology for treating arthrofibrosis.

Direct Repair of the Superior Band of Bigelow's Ligament After Hip Arthroplasty: a Surgical Technique

BACKGROUND

The posterolateral approach is one of the most common approaches used during hip arthroplasty. A posterior soft tissue repair is necessary to limit the risk of postoperative dislocation. For a trapezoidal capsulotomy, the proximal limb divides the superior band of the iliofemoral ligament (Bigelow's ligament). A transosseous repair frequently leaves a defect in this region, which may elevate the risk for dislocation. The purpose of this article is to describe a simple, rational technique for reinforcing the posterior capsular repair.

DESCRIPTION OF TECHNIQUE

A meticulous exposure of the hip capsule is performed during the posterolateral surgical approach. A trapezoidal capsulotomy is performed. After implantation of the arthroplasty implants, retractors are placed to expose the superior capsule. Prior to transosseous repair of the capsule and short external rotator tendons, the proximal limb of the capsulotomy is reapproximated anatomically and repaired with non-absorbable sutures. If anatomical repair is not possible, leg length and femoral offset should be reassessed carefully.

DISCUSSION

The described modification may further minimize the risk of dislocation following hip arthroplasty, as the superior band of Bigelow's ligament is an additional checkrein to internal and external rotation. This repair provides a secondary intraoperative assessment of leg length and femoral offset to ensure proper biomechanical reconstruction of the hip joint. It is the authors' preferred technique of all hip hemiarthroplasties and total hip arthroplasties, whenever possible.

Posttraumatic elbow joint contractures: defining pathologic capsular mechanisms and potential future treatment paradigms

The Andrew J. Weiland Medal is presented by the American Society for Surgery of the Hand to a midcareer researcher who is dedicated to advancing patient care in the field of hand surgery. This essay, awarded the Weiland Medal in 2012, focuses on posttraumatic elbow joint contractures. Joint contractures are well known to hand surgeons because they limit function of our patients. There is a thorough understanding of the pathoanatomy underlying joint contractures. However, the mechanisms leading to the pathoanatomy are either unknown or partially understood, depending on the etiology of the particular clinical condition. This review describes our research over the past 14 years on posttraumatic elbow joint contractures. It defines pathologic cellular, matrix, and growth factor changes in the joint capsule, elaborates on the development of an animal model of posttraumatic joint contractures, presents an evaluation of a potential prevention strategy based on our research, and outlines future plans to bring this work to the clinical realm for the benefit of patients.

Posterior glenohumeral joint capsule contracture

Glenohumeral joint posterior capsule contracture may cause shoulder pain by altering normal joint mechanics. Contracture is commonly noted in throwing athletes but can also be present in nonthrowers. The cause of contracture in throwing athletes is assumed to be a response to the high amount of repetitive tensile force placed on the tissue, whereas the mechanism of contracture in nonthrowers is unknown. It is likely that mechanical and cellular processes interact to increase the stiffness and decrease the compliance of the capsule, although the exact processes that cause a contracture have not been confirmed. Cadaver models have been used to study the effect of posterior capsule contracture on joint mechanics and demonstrate alterations in range of motion and in humeral head kinematics. Imaging has been used to assess posterior capsule contracture, although standard techniques and quantification methods are lacking. Clinically, contracture manifests as a reduction in glenohumeral internal rotation and/or cross body adduction range of motion. Stretching and manual techniques are used to improve range of motion and often decrease symptoms in painful shoulders.

Histological study of the extratympanic portion of the discomallear ligament in adult humans: a functional hypothesis

This study was carried out on histological aspects of the extratympanic portion of the discomallear ligament (DL) in adult humans. The temporomandibular joint (TMJ) was dissected bilaterally in 20 cadavers; in 15 cases the articular disc (AD) and the retroarticular tissue were extirpated. The extratympanic portion of the DL had the shape of a base-down triangle, in relation to the AD, and an upper vertex, in relation to the petrotympanic fissure. In five cases, the base, measured bilaterally, had an average length of 6.4 mm, while the distance from the base to the upper vertex averaged 9.3 mm in length. The extratypanic portion of the DL is an intrinsic ligament of the TMJ, composed of collagen fibres and abundant elastic fibres. We propose that this ligament could act as a tensor of the synovial membrane in movements of the TMJ.

Joint capsule mast cells and neuropeptides are increased within four weeks of injury and remain elevated in chronic stages of posttraumatic contractures

The purpose of this article was to determine mast cell and neuropeptide nerve fiber numbers in joint capsules in posttraumatic contractures, as elevated numbers have been implicated in other fibrotic and contracture conditions. Twelve skeletally mature rabbits had intraarticular cortical windows removed from the medial and lateral femoral condyles and the knee joint immobilized. The contralateral unoperated limb served as a control. Equal numbers of rabbits were sacrificed 4 weeks after surgery or 40 weeks after the first surgery that included 32 weeks of remobilization. Six patients with chronic posttraumatic elbow joint contractures and six age-matched organ donor controls free of elbow contractures were also studied. Joint capsule myofibroblast, mast cell, and neuropeptide containing nerve fiber numbers were assessed with immunohistochemistry. The numbers of myofibroblasts, mast cells, and neuropeptide containing nerve fibers expressed as a percentage of total cells were significantly greater in the contracture capsules when compared to the control capsules at all time points (p < 0.0001). The range of percentages for the three components in the contracture capsules versus the controls were 41-48% versus 9-10%, 44-50% versus 11-13%, and 45-50% versus 10-12% for the acute and chronic stages of the rabbit model and the chronic stages in the human elbows, respectively. These data support the hypothesis that a myofibroblast-mast cell-neuropeptide fibrosis axis may underlie some of the pathologic changes in the joint capsule in posttraumatic contractures. Approaches designed to manipulate this axis, such as preventing degranulation of mast cells, warrant further investigation.

Comparison of human lumbar facet joint capsule strains during simulated high-velocity, low-amplitude spinal manipulation versus physiological motions

BACKGROUND CONTEXT

Spinal manipulation (SM) is an effective treatment for low back pain (LBP), and it has been theorized that SM induces a beneficial neurophysiological effect by stimulating mechanically sensitive neurons in the lumbar facet joint capsule (FJC).

PURPOSE

The purpose of this study was to determine whether human lumbar FJC strains during simulated SM were different from those that occur during physiological motions.

STUDY DESIGN/SETTING

Lumbar FJC strains were measured in human cadaveric spine specimens during physiological motions and simulated SM in a laboratory setting.

METHODS

Specimens were tested during displacement-controlled physiological motions of flexion, extension, lateral bending, and axial rotations. SM was simulated using combinations of manipulation site (L3, L4, and L5), impulse speed (5, 20, and 50 mm/s), and pre-torque magnitude (applied at T12 to simulate patient position; 0, 5, 10 Nm). FJC strains and vertebral motions (using six degrees of freedom) were measured during both loading protocols.

RESULTS

During SM, the applied loads were within the range measured during SM in vivo. Vertebral translations occurred primarily in the direction of the applied load, and were similar in magnitude regardless of manipulation site. Vertebral rotations and FJC strain magnitudes during SM were within the range that occurred during physiological motions. At a given FJC, manipulations delivered distally induced capsule strains similar in magnitude to those that occurred when the manipulation was applied proximally.

CONCLUSIONS

FJC strain magnitudes during SM were within the physiological range, suggesting that SM is biomechanically safe. Successful treatment of patients with LBP using SM may not require precise segmental specificity, because the strain magnitudes at a given FJC during SM do not depend upon manipulation site.

Evidence of a hypermineralised calcified fibrocartilage on the human femoral neck and lesser trochanter

Femoral neck fractures are a major cause of morbidity and mortality in elderly humans. In addition to the age-related loss of cancellous bone, changes to the microstructure and morphology of the metaphyseal cortex may be a contributing factor in osteoporotic hip fractures. Recent investigations have identified a hypermineralised tissue on the neck of the femur and trochanteric region that increases in fractional area with advancing age in both males (Boyce & Bloebaum, 1993) and females (Vajda & Bloebaum, 1999). The aim of this study was to determine if the hypermineralised tissue previously observed on the proximal femur is calcified fibrocartilage. Regional variations in the fractional area of hypermineralised tissue, cortical bone, and porosity of the cortical bone along the neck of the femur and lesser trochanter were also quantified. Comparison of back scattered electron and light microscope images of the same area show that regions of hypermineralised tissue correlate with the regions of calcified fibrocartilage from tendon and capsular insertions. The hypermineralised tissue and calcified fibrocartilage had similar morphological features such as the interdigitations of the calcified fibrocartilage into the bone, lacunar spaces, and distinctly shaped pores adjacent to the 2 tissues. Regions of the neck that did not contain insertions were covered with periosteum. There were no regional differences (P > 0.05) on the superior and inferior femoral neck in terms of the percentage area of hypermineralised calcified fibrocartilage, cortical bone, or cortical bone porosity. The lesser trochanter exhibited regional differences in the fractional area of hypermineralised calcified fibrocartilage (P = 0.007) and cortical bone (P = 0.007) but not porosity of the cortical bone (P > 0.05). The effects of calcified fibrocartilage on femoral neck periosteal expansion, repair, and mechanics are unknown, but may play a role in osteoporotic fractures and intracapsular fracture healing.