Effects of a delayed steroid injection on ligament healing using a rabbit medial collateral ligament model

Mesenchymal Stem Cells for Enhanced Healing of the Medial Collateral Ligament of the Knee Joint

Background and Objectives: The medial collateral ligament (MCL) is one of the major supporting ligaments of the knee joint, and MCL injuries are common where excessive valgus loading is applied to the knee joint. Although most MCL injuries can be treated conservatively, healing of the MCL can take several weeks to months. Furthermore, once injured, the biomechanical properties of the healed MCL differ from those of the native MCL, resulting in an increased risk of re-injury and chronic remnant symptoms. Mesenchymal stem cells (MSCs), owing to their therapeutic potential, have been investigated in various musculoskeletal injuries, and some preclinical studies regarding MSC-based approaches in MCL injuries have shown promising results. Despite satisfactory results in preclinical studies, there is still a lack of clinical studies in the orthopedic literature. This article describes the basic knowledge of the MCL, standard treatments for MCL injuries, and recent studies regarding the application of MSCs for enhanced healing of the MCL. MSC-based approaches are expected to be a potential therapeutic option for enhanced healing of the MCL in the future.

Nonsurgical Management of Ulnar Collateral Ligament Injuries

Ulnar collateral ligament (UCL) injuries are a common source of pain and disability in the overhead athlete and often result in notable loss of time from competition. Over the past 10 to 15 years, the prevalence of UCL injury and reconstruction has undergone a dramatic increase, making it imperative to determine which patients may benefit from a nonsurgical regimen. Nonsurgical treatment involves a multidisciplinary approach of rehabilitation with tailored physical therapy programs and, in certain cases, biologic adjuncts. Physical therapy protocols should focus on strengthening the periscapular muscles, rotator cuff, core musculature, and flexor pronator mass to help stabilize the injured elbow and prevent injury recurrence before the initiation of a progressive throwing program. The implementation of injury prevention programs has shifted the focus from just the elbow and have included the shoulder, legs, and core in an effort to help decrease the stress on the upper extremity. In addition, biologic therapies such as platelet-rich therapy are promising modalities to augment the conservative treatment of UCL injuries but remain under investigation. The purpose of this study is to review available strategies and outcomes for conservatively treating UCL injuries.

Methylprednisolone acetate mitigates IL1β induced changes in matrix metalloproteinase gene expression in skeletally immature ovine explant knee tissues

OBJECTIVE AND DESIGN

This study aimed at evaluating the effect of methylprednisolone (MPA) on messenger ribonucleic acid (mRNA) expression levels in immature ovine knee joint tissue explants following interleukin (IL)1β induction and to assess responsiveness of the explants.

MATERIAL OR SUBJECTS

Explants were harvested from the articular cartilage, synovium, and infrapatellar fat pad (IPFP) from immature female sheep.

TREATMENT

Methylprednisolone.

METHODS

The samples were allocated into six groups: (1) control, (2) MPA (10^-3 M), (3) MPA (10^-4 M), (4) IL1β, (5) IL1β + 10^-3 M MPA, or (6) IL1β + 10^-4 M MPA. mRNA expression levels for molecules relevant to inflammation, cartilage degradation/anabolism, activation of innate immunity, and adipose tissue/hormones were quantified. Fold changes with MPA treatment were compared via the comparative C_T method.

RESULTS

Methylprednisolone treatment significantly suppressed MMPs consistently across the cartilage (MMP1, MMP3, and MMP13), synovium (MMP1 and MMP3), and IPFP (MMP13) (all p < 0.05). Other genes that were less consistently suppressed include endogenous IL1β (cartilage) and IL6 (IPFP) (all p < 0.05), and others not affected either by IL-1 exposure or subsequent MPA include TGFβ1, TLR4, and adipose-related molecules.

CONCLUSIONS

Methylprednisolone significantly mitigated IL1β induced mRNA expression for MMPs in the immature cartilage, synovium, and IPFP, but the extent of the responsiveness was tissue-, location-, and gene-specific.

Gastric pentadecapeptide body protection compound BPC 157 and its role in accelerating musculoskeletal soft tissue healing

There is a current need for a therapy that can alleviate the social and economic burden that presents itself with debilitating and recurring musculoskeletal soft tissue injuries and disorders. Currently, several therapies are emerging and undergoing trials in animal models; these focus on the manipulation and administration of several growth factors implicated with healing. However, limitations include in vivo instability, reliance on biocompatible and robust carriers and restricted application procedures (local and direct). The aim of this paper is therefore to critically review the current literature surrounding the use of BPC 157, as a feasible therapy for healing and functional restoration of soft tissue damage, with a focus on tendon, ligament and skeletal muscle healing. Currently, all studies investigating BPC 157 have demonstrated consistently positive and prompt healing effects for various injury types, both traumatic and systemic and for a plethora of soft tissues. However, to date, the majority of studies have been performed on small rodent models and the efficacy of BPC 157 is yet to be confirmed in humans. Further, over the past two decades, only a handful of research groups have performed in-depth studies regarding this peptide. Despite this, it is apparent that BPC 157 has huge potential and following further development has promise as a therapy to conservatively treat or aid recovery in hypovascular and hypocellular soft tissues such as tendon and ligaments. Moreover, skeletal muscle injury models have suggested a beneficial effect not only for disturbances that occur as a result of direct trauma but also for systemic insults including hyperkalamia and hypermagnesia. Promisingly, there are few studies reporting any adverse reactions to the administration of BPC 157, although there is still a need to understand the precise healing mechanisms for this therapy to achieve clinical realisation.

The Collateral Ligament of the Digits of the Hand: Anatomy, Physiology, Biomechanics, Injury, and Treatment

Ligament injuries are among the most common musculoskeletal injuries seen in clinical practice and ligaments are the most frequently injured structures in a joint. Ligaments play an important role in balancing joint mobility and joint stability. Disruption of joint ligaments severely impairs joint function. Over the past 10 years, a new appreciation of a neuroanatomy and neurophysiology of joint ligaments and its biofeedback loops to surrounding muscles and tendons has emerged to explain the relationship between primary and secondary restraints that allow normal joint motion yet prevent pathological motion. This review focuses on this recent information with a view to new clinical approaches to these common problems.

Systemic corticosteroids improve tendon healing when given after the early inflammatory phase

Inflammation initiates tendon healing and then normally resolves more or less completely. Unresolved inflammation might disturb the remodeling process. We hypothesized that suppression of inflammation during the early remodeling phase by systemic dexamethasone treatment can improve healing. 36 rats underwent Achilles tendon transection and were randomized to dexamethasone or saline on days 0-4 after surgery (early inflammatory phase), and euthanasia day 7. Another 54 rats received injections days 5-9 (early remodeling phase) and were euthanized day 12 for mechanical, histological and flow cytometric evaluation. Dexamethasone treatment days 0-4 reduced the cross-sectional area, peak force and stiffness by day 7 to less than half (p < 0.001 for all), while material properties (peak stress and elastic modulus) were not significantly affected. In contrast, dexamethasone treatment days 5-9 increased peak force by 39% (p = 0.002) and stiffness by 58% (p < 0.001). The cross-sectional area was reduced by 42% (p < 0.001). Peak stress and elastic modulus were more than doubled (p < 0.001 for both). Semi-quantitative histology at day 12 showed that late dexamethasone treatment improved collagen alignment, and flow cytometry revealed reduced numbers of CD8a+ cytotoxic T cells in the tendon callus. These results suggest that downregulation of lingering inflammation during the early remodeling phase can improve healing.

Corticosteroids reduce the tensile strength of isolated collagen fascicles

BACKGROUND

Overuse tendon injuries are frequent. Corticosteroid injections are commonly used as treatment, although their direct effects on the material properties of the tendon are poorly understood.

PURPOSE

To examine the influence of corticosteroids on the tensile strength of isolated collagen fascicles.

STUDY DESIGN

Controlled laboratory study.

METHODS

Single strands (300-500 mum) of rat-tail collagen fascicles were incubated in either high (1 mL of 40 mgmL(-1) mixed with 0.5 mL saline 9%) or low (1 mL of 40 mgmL(-1) mixed with 2 mL saline 9%) concentration of methylprednisolone acetate (Depomedrol) for 3 or 7 days, while the control segment from the same fascicle was kept in saline (N = 64). After the incubation period, the fascicles underwent displacement to failure in a mechanical test rig at 0.13 mm/s, and thereafter hydroxylysyl pyridinoline and lysyl pyridinoline cross-link content was evaluated in a high-performance liquid chromatography system. Data for each group were analyzed with a 2-way analysis of variance (time x incubation) for ultimate stress (mean +/- standard deviation).

RESULTS

In the high-concentration groups, strength was reduced after 3 (16.6 +/- 4.6 MPa) and 7 (8.6 +/- 1.7 MPa) days compared to the controls (30.2 +/- 5.0 MPa and 25.6 +/- 4.6 MPa, respectively; P < .05). In the low-concentration groups, strength was reduced after 3 (12.0 +/- 3.1 MPa) and 7 days (10.9 +/- 2.5 MPa) compared to the controls (31.5 +/- 5.0 MPa and 32.4 +/- 5.6 MPa, respectively; P < .05). The amount of cross-linking was unaffected by the intervention.

CONCLUSION

Data show that the tensile strength of isolated fascicles is markedly reduced after 3- and 7-day incubation in both high and low concentration of corticosteroids, although the observed effect on whole tendon remains unknown.

CLINICAL RELEVANCE

Corticosteroids may weaken specific regions of the injected tendon and leave it more prone to rupture. This weakening effect is manifested in the individual collagen fascicles that constitute the tendon.

The healing rabbit medial collateral ligament of the knee responds to systemically administered glucocorticoids differently than the uninjured tissues of the same joint or the uninjured MCL: a paradoxical shift in impact on specific mRNA levels and MMP-13 protein expression in injured tissues

The impact and molecular mechanism of action of glucocorticoids in connective tissues is largely unclear, even though widely used, and whether factors such as injury and inflammation modulate this response has not been elucidated. This study describes the role of glucocorticoids in the regulation of mRNA levels for collagens I and III, MMP-13, biglycan, decorin, COX-2 and the glucocorticoid receptor in connective tissues of normal and injured joints in an established rabbit in vivo MCL scar model, and examines the potential mechanism(s) involved. In vitro promoter studies were performed using an MMP-13 promoter-luciferase expression construct in transient transfection assays with a rabbit synovial cell line (HIG-82) to identify sites of glucocorticoid-mediated transcriptional regulation and the promoter elements involved. The in vivo results indicate that scar tissue from different phases of healing (early inflammatory, granulation tissue and neovascular, and later remodelling phases, respectively) displays a different pattern of responsiveness to glucocorticoid treatment than uninjured tissue and that this responsiveness is gene dependent. The most significant impact was seen for genes such as collagen I, collagen III and MMP-13, all of which are involved in connective tissue structure and remodelling. The in vitro studies confirmed the apparent in vivo glucocorticoid-mediated response of MMP-13 mRNA and implicated the AP-1 site of the MMP-13 promoter in this regulation. Immunohistochemistry studies showed increased MMP-13 protein expression, consistent with the mRNA findings, following glucocorticoid treatment in injured tissue but not normal tissues. In conclusion, connective tissue responsiveness to glucocorticoid treatment varies depending on injury and the stage of healing of the tissue, and consequently, glucocorticoid-responsiveness may be modulated differently in states of injury and inflammation.

Plantar fasciopathy and orthotripsy: the effect of prior cortisone injection

BACKGROUND

Corticoid steroid injection into the heel is a popular treatment method for painful heel syndromes. However, the positive results usually are short term. Extracorporeal shock wave treatment (ESW) has been shown to have a more permanent effect. We evaluated 555 patients who received ESW using the device Ossa Tron Orthotripsy (Health Tronics, Surgical Services, Marietta, GA) relative to antecedent cortisone heel injection.

METHODS

Before ESW, 312 patients (56%) received one or more cortisone injections into the heel, and 243 patients (44%) had never received a cortisone injection.

RESULTS

Two hundred and thirty-four patients (75%) who had antecedent injection or injections had positive outcomes after ESW. One hundred sixty-eight patients (69%) without prior heel injection had positive responses after ESW.

CONCLUSION

The prior injection of cortisone did not affect the likelihood of a positive response to ESW. Similarly, the absence of prior injection of cortisone did not affect the outcome.

Effects of iontophoretic versus injection administration of dexamethasone

PURPOSE

Sixty-eight skeletally mature New Zealand white rabbits were used to study the effects of iontophoresis- and injection-delivered sodium phosphate dexamethasone (DX) on the morphologic, histologic, microscopic, and biomechanical properties of uninjured rabbit patellar tendons over an initial 14-d period.

METHODS

Three control (untreated, placebo iontophoresis, and placebo injection) groups and two treatment (iontophoresis and injection) groups underwent serum, ELISA tendon, histology, electron microscopy, and biomechanical analysis.

RESULTS

Serum DX levels were detectable and quantifiable in both treatment groups at 1 h but were significantly greater (P < 0.05) in the injected group (11.29 ng.mL-1) compared with the iontophoresis group (6.34 ng.mL-1). The most significant histologic finding was a lack of a cellular inflammatory response in the DX-treated groups at 24 h. Ultrastructural analysis produced no significant differences between size or size ratio of collagen fibrils among any groups. Morphologic examination revealed only injection puncture marks seen in appropriate tendons. Biomechanical testing produced disruption at the patellar insertion in 81% of the specimens. No injected tendon failed at the injection site. Normalized biomechanical properties included: 1) Stiffness increased in control and iontophoresis groups from 1 to 24 h, then gradually declined; the DX-injected specimens showed a similar but delayed effect. 2) Peak load at failure for iontophoresis and control groups was greatest at 24 h. The DX-injected group again showed a delayed response. 3) In general, total energy to failure revealed no significant differences between groups at any time period.

CONCLUSION

It appears that iontophoresis or injection-delivered DX may produce anti-inflammatory effects without significantly altering ultrastructural or biomechanical characteristics of the rabbit patellar tendon within an initial 14-d period.

Effects of methylprednisolone and betamethasone injections on the rotator cuff: an experimental study in rats

Thirty-one female Sprague-Dawley rats were used to determine the effects of subacromial corticosteroid injections on the rotator cuff. The injection technique was tested in 6 animals, which were excluded from the study. The remaining 25 rats were randomly divided into three groups of 8 animals each; a single rat received no injections. Every other week for 8 weeks, one shoulder in each rat was injected with methylprednisolone, betamethasone, or saline in a dosage equivalent to that used in humans. The supraspinatus and infraspinatus tendons were removed 10 days after the last injection and evaluated. There were no pathologic changes in the tendons injected with saline. In 43% of the methylprednisolone-treated rats and 29% of the betamethasone-treated rats, the tendons were abnormally soft and light-colored. In 43% of the methylprednisolone group and 71% of the betamethasone group, fragmentation of collagen bundles and inflammatory cell infiltration were evident. Subacromial injections of methylprednisolone or betamethasone repeated frequently can cause deleterious changes in the normal structure of the rat rotator cuff. In light of these findings, therapy for subacromial impingement syndrome of the shoulder with frequent, repeated steroid injections is potentially harmful.

Effect of steroid injections on the rotator cuff: an experimental study in rats

The aim of this study was to evaluate the effects of repeated steroid injections into the subacromial space. Thirty rats were injected either 3 or 5 times with triamcinolone in a dosage equivalent to that given to human beings or 3 or 5 times with saline into the subacromial space. One rat received no injection. The supraspinatus and infraspinatus tendons were evaluated macroscopically and microscopically. Two different staining methods were used on each sample including hematoxylin eosin and Miller's elastin/van Gieson's solution. After 5 steroid injections, we found focal inflammation, necrosis, and fragmentation of collagen bundles in the tendon in 4 of 7 rats. The tendons of the controls showed a normal structure (P < .05). There were no pathologic changes among the rats that were injected with triamcinolone 3 times. These results show that repeated subacromial injections of triamcinolone may cause damage to the rotator cuff of the rat. This finding may indicate cautious use of subacromial steroid injections in human beings.