Early Tensile Loading in Nonsurgically Treated Achilles Tendon Ruptures Leads to a Larger Tendon Callus and a Lower Elastic Modulus: A Randomized Controlled Trial.

Background: Early tensile loading improves material properties of healing Achilles tendon ruptures in animal models and in surgically treated human ruptures. However, the effect of such rehabilitation in patients who are nonsurgically treated remains unknown.

Hypothesis: In nonsurgically treated Achilles tendon ruptures, early tensile loading would lead to higher elastic modulus 19 weeks after the injury compared with controls.

Dexamethasone Enhances Achilles Tendon Healing in an Animal Injury Model, and the Effects Are Dependent on Dose, Administration Time, and Mechanical Loading Stimulation.

Background: Corticosteroid treatments such as dexamethasone are commonly used to treat tendinopathy but with mixed outcomes. Although this treatment can cause tendon rupture, it can also stimulate the tendon to heal. However, the mechanisms behind corticosteroid treatment during tendon healing are yet to be understood.

Antiresorptive treatment and talar collapse after displaced fractures of the talar neck: a long-term follow-up of 19 patients.

Background and purpose - Displaced fractures of the talar neck are associated with a high risk of structural collapse. In this observational analysis we hypothesized that pharmacological inhibition of osteoclast function might reduce the risk of structural collapse through a reduction in bone resorption during revascularization of the injured bone.Patients and methods - Between 2002 and 2014 we treated 19 patients with displaced fractures of the talar neck with open reduction and internal fixation.

Diminishing effects of mechanical loading over time during rat Achilles tendon healing.

Mechanical loading affects tendon healing and recovery. However, our understanding about how physical loading affects recovery of viscoelastic functions, collagen production and tissue organisation is limited. The objective of this study was to investigate how different magnitudes of loading affects biomechanical and collagen properties of healing Achilles tendons over time.

Single postoperative infusion of zoledronic acid to improve patient-reported outcome after hip or knee replacement: study protocol for a randomised, controlled, double-blinded clinical trial.

Introduction: In Sweden, roughly 3000 patients are reoperated each year due to pain and loss of function related to a loosened hip or knee prosthesis. These reoperations are strenuous for the patient, technically demanding and costly for the healthcare system. Any such reoperation that can be prevented would be of great benefit.

Response to mechanical loading in rat Achilles tendon healing is influenced by the microbiome.

We have previously shown that changes in the microbiome influence how the healing tendon responds to different treatments. The aim of this study was to investigate if changes in the microbiome influence the response to mechanical loading during tendon healing. 90 Sprague-Dawley rats were used.

Statin treatment increases the clinical risk of tendinopathy through matrix metalloproteinase release - a cohort study design combined with an experimental study.

Recent experimental evidence indicates potential adverse effects of statin treatment on tendons but previous clinical studies are few and inconclusive. The aims of our study were, first, to determine whether statin use in a cohort design is associated with tendinopathy disorders, and second, to experimentally understand the pathogenesis of statin induced tendinopathy. We studied association between statin use and different tendon injuries in two population-based Swedish cohorts by time-dependent Cox regression analysis.

Chronic anterior tibial stress fractures in athletes: No crack but intense remodeling.

Purpose: Delayed healing of anterior tibial stress fractures in athletes is related to high tensional forces acting across a putative fracture gap. These forces lead to crack propagation and create strains that exceed tissue differentiation thresholds for new bone to form in the gap. The "dreaded black line" is a radiographic hallmark sign of stress fractures considered to represent a transverse fracture gap.

Depletion of cytotoxic (CD8+) T cells impairs implant fixation in rat cancellous bone.

As cytotoxic (CD8 ) T cells seem to impair shaft fracture healing, we hypothesized that depletion of CD8 cells would instead improve healing of cancellous bone. Additionally, we also tested if CD8-depletion would influence the healing of ruptured Achilles tendons. Rats received a single injection of either anti-CD8 antibodies or saline and put through surgery 24 h later.

Different composition of leucocytes in cortical and cancellous bone healing in a mouse model.

Objectives: Cortical and cancellous bone healing processes appear to be histologically different. They also respond differently to anti-inflammatory agents. We investigated whether the leucocyte composition on days 3 and 5 after cortical and cancellous injuries to bone was different, and compared changes over time using day 3 as the baseline.

Impact of a zoledronate coating on early post-surgical implant stability and marginal bone resorption in the maxilla-A split-mouth randomized clinical trial.

Objectives: The objective of this clinical study was to evaluate the effect of a bisphosphonate coating on a titanium implant on the implant stability quotient (ISQ) and the radiographic marginal bone levels at implants during early healing (2-8 weeks).

Materials And Methods: In a randomized double-blind trial with internal controls, 16 patients received a dental implant coated with zoledronate and one uncoated implant as a control. The coated and uncoated implants which were visually indistinguishable were bone level titanium implants with a moderately rough surface and a microthreaded neck.

Abaloparatide versus teriparatide: a head to head comparison of effects on fracture healing in mouse models.

Background and purpose - Teriparatide accelerates fracture healing in animals and probably in man. Abaloparatide is a new drug with similar although not identical effects on the teriparatide receptor. Given at 4 times the teriparatide dose in a human osteoporosis trial, abaloparatide increased bone density more than teriparatide, and both reduced fracture risk.

Stimulation of Tendon Healing With Delayed Dexamethasone Treatment Is Modified by the Microbiome.

Background: The immune system reflects the microbiome (microbiota). Modulation of the immune system during early tendon remodeling by dexamethasone treatment can improve rat Achilles tendon healing. The authors tested whether changes in the microbiota could influence the effect of dexamethasone treatment.

Different mechanisms activated by mild versus strong loading in rat Achilles tendon healing.

Background: Mechanical loading stimulates Achilles tendon healing. However, various degrees of loading appear to have different effects on the mechanical properties of the healing tendon, and strong loading might create microdamage in the tissue. This suggests that different mechanisms might be activated depending on the magnitude of loading.

Osteoblast precursors and inflammatory cells arrive simultaneously to sites of a trabecular-bone injury.

Background and purpose - Fracture healing in the shaft is usually described as a sequence of events, starting with inflammation, which triggers mesenchymal tissue formation in successive steps. Most clinical fractures engage cancellous bone. We here describe fracture healing in cancellous bone, focusing on the timing of inflammatory and mesenchymal cell type appearance at the site of injury Material and methods - Rats received a proximal tibial drill hole.

Cox-2 inhibition and the composition of inflammatory cell populations during early and mid-time tendon healing.

Background: During early tendon healing, the cells within the regenerating tissue are, to a large part, inflammatory leukocytes (CD45). In a rat Achilles tendon healing model, the inflammation resolves between 5 and 10 days. In the same model, Cox inhibitors (NSAIDs) impair healing when given during the first 5 days, but have a positive effect if given later.

Achilles tendon compositional and structural properties are altered after unloading by botox.

Tendon function and homeostasis rely on external loading. This study investigates the biological mechanisms behind tendon biomechanical function and how the mechanical performance is affected by reduced daily loading. The Achilles tendons of 16 weeks old female Sprague Dawley rats (n = 40) were unloaded for 5 weeks by inducing muscle paralysis with botulinum toxin injections in the right gastrocnemius and soleus muscles.

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.

Marrow compartment contribution to cortical defect healing.

Background and purpose - Healing of shaft fractures is commonly described as regards external callus. We wanted to clarify the role of the bone marrow compartment in the healing of stable shaft fractures. Patients and methods - A longitudinal furrow was milled along the longitudinal axis of the femoral shaft in mice.

Shining dead bone-cause for cautious interpretation of [F]NaF PET scans.

Background and purpose - [F]Fluoride ([F]NaF) PET scan is frequently used for estimation of bone healing rate and extent in cases of bone allografting and fracture healing. Some authors claim that [F]NaF uptake is a measure of osteoblastic activity, calcium metabolism, or bone turnover. Based on the known affinity of fluoride to hydroxyapatite, we challenged this view.

Mechanical instability and titanium particles induce similar transcriptomic changes in a rat model for periprosthetic osteolysis and aseptic loosening.

Wear debris particles released from prosthetic bearing surfaces and mechanical instability of implants are two main causes of periprosthetic osteolysis. While particle-induced loosening has been studied extensively, mechanisms through which mechanical factors lead to implant loosening have been less investigated. This study compares the transcriptional profiles associated with osteolysis in a rat model for aseptic loosening, induced by either mechanical instability or titanium particles.

Different gene response to mechanical loading during early and late phases of rat Achilles tendon healing.

Mechanical loading stimulates tendon healing both when applied in the inflammatory phase and in the early remodeling phase of the process, although not necessarily via the same mechanisms. We investigated the gene response to mechanical loading in these two phases of tendon healing. The right Achilles tendon in rats was transected, and the hindlimbs were unloaded by tail suspension.