Close negative correlation of local and circulating Dickkopf-1 and Sclerostin levels during human fracture healing.

Wnt signaling is critically involved in fracture healing. Existing data predominantly relies on rodent models. Here, we explored local and circulating Dickkopf-1 (DKK1) levels in patients with respect to fracture healing and explore its association to sclerostin (SOST). 69 patients after surgical stabilization of long bone fractures of which six patients had impaired fracture healing were included in this study. Life-style and patient related factors with a known effect on DKK1 and SOST were recorded. DKK1 and SOST concentrations were measured using enzyme-linked immunosorbent assay (ELISA) at the fracture site and in circulation. DKK1 and SOST showed a close inverse correlation. In fracture hematoma and immediately after trauma DKK1 levels were significantly reduced while SOST levels were significantly increased, compared to healthy control. Postoperatively, DKK1 peaked at week 2 and SOST at week 8, again demonstrating a close negative correlation. Age and smoking status affected the balance of DKK1 and SOST, while type 2 diabetes and sex did not demonstrate a significant influence. Early postoperative elevation of SOST without compensatory DKK1 decrease was associated with fracture non-union in younger patients (< 50a). The close inverse correlation and very rapid dynamics of DKK1 and SOST locally as well as systemically suggest their critical involvement during human fracture healing. Importantly, as immediate compensatory feedback mechanism are apparent, we provide evidence that dual-blockade of DKK1 and SOST could be critical to allow for therapeutic efficiency of Wnt targeted therapies for fracture healing.

Functional outcome of an 'all-inside' technique in female anterior cruciate ligament reconstruction at long-term follow-up: A gender-sensitive analysis.

BACKGROUND: As the awareness towards gender-specific therapies continues to increase among all fields of medicine, so does the need for gender-sensitive evaluations of established surgical techniques. With a higher likelihood of anterior cruciate ligament injury in women, a critical assessment of the functional outcome of anterior cruciate ligament reconstruction regarding patient sex is indispensable. Almost all pre-existing literature on this subject is based on anterior cruciate ligament reconstructions carried out before 2008, when 'all-inside' techniques did not exist. This implicates the need to investigate this technique towards its differences in outcome between male and female patients. OBJECTIVES: The purpose of this study was to determine whether there is a difference concerning the functional outcome of an 'all-inside' technique for anterior cruciate ligament reconstruction in female patients when compared to a cohort of male patients matched for body mass index and age. DESIGN: Retrospective analysis. METHODS: All female patients who underwent anterior cruciate ligament reconstruction using an all-inside technique between 2011 and 2012 were examined for inclusion. Functional outcome parameters investigated included the Lysholm Knee Score, International Knee Documentation Committee score, Visual Analogue Scale score and the Tegner Activity Scale. All parameters were documented before surgery and at 3-, 6-, 12- and >24 months follow-up. At 24-month follow-up, anterior-posterior knee laxity was tested using the KT-2000 arthrometer device. For comparison, an equivalent group of male patients who underwent the same procedure was matched. RESULTS: 27 female patients were matched with 27 male patients. The average age was 29 years, and a mean follow-up of 90 months could be achieved with 27 of patients reaching a follow-up of > 10 years. The evaluated scores showed no significant difference between female and male patients. Women presented with poorer functional outcome at 3- as well as 6-month follow-ups compared to men, without reaching statistical significance. After 12 months, no further differences could be found. CONCLUSION: This study proved that an all-inside technique for anterior cruciate ligament reconstruction is able to produce the same functional outcome in female as in male patients at long-term follow-up. The results on short-term outcome indicate the need for further research towards gender-specific differences after anterior cruciate ligament reconstruction, their potential causes and potential of improvement. LEVEL OF EVIDENCE: Level III, retrospective comparative study.

Distal locking technique affects the rate of iatrogenic radial nerve palsy in intramedullary nailing of humeral shaft fractures.

BACKGROUND: Intramedullary humeral nailing is a common and reliable procedure for the treatment of humeral shaft fractures. Radial nerve palsy is a common complication encountered in the treatment of this pathology. The radial nerve runs from posterior to anterior at the lateral aspect of the distal humerus. Hence, there is reason to believe that due to the anatomic vicinity of the radial nerve in this area, lateral-medial distal locking in intramedullary nailing of the humerus may be associated with a greater risk for iatrogenic radial nerve injury compared to anterior-posterior locking. QUESTIONS/PURPOSE: To assess whether the choice of distal locking (lateral-medial versus anterior-posterior distal locking) in intramedullary humeral nailing of humeral shaft fractures affects the risk for iatrogenic radial nerve injury. PATIENTS AND METHODS: Overall, 203 patients (116 females, mean age 64.3 ± 18.6 years), who underwent intramedullary nailing of the humerus between 2000 and 2020 at a single level-one trauma center, met the inclusion criteria and were analyzed in this retrospective case-control study. Patients were subdivided into two groups according to the distal locking technique. RESULTS: Anterior-posterior locking was performed in 176 patients versus lateral-medial locking in 27 patients. We observed four patients with iatrogenic radial nerve palsy in both groups. Risk for iatrogenic radial nerve palsy was almost 7.5 times higher for lateral-medial locking (OR 7.48, p = 0.006). There was no statistically significant difference regarding intraoperative complications, union rates or revision surgeries between both groups. CONCLUSIONS: Lateral-medial distal locking in intramedullary nailing of the humerus may be associated with a greater risk for iatrogenic radial nerve palsy than anterior-posterior locking. Hence, we advocate for anterior-posterior locking. LEVEL OF EVIDENCE: Level III retrospective comparative study.

Functional Outcome of All-Soft-Tissue Quadriceps Tendon Autograft in ACL Reconstruction in Young and Athletic Patients at a Minimum Follow-Up of 1 Year.

To investigate the functional outcome in young and athletic patients with ACL injuries, treated with an all-soft-tissue quadriceps tendon autograft at a minimum follow-up of 12 months. Methods: Patients who received a QT autograft ACL reconstruction between August 2018 and December 2020 were included in this study. Range of motion in the operated knee was described at 6 and 18 weeks after surgery and the functional outcome parameters (Lysholm score, IKDC score and Tegner activity scale) were calculated at 6 and ≥ 12 months after surgery. Results: Forty patients were included in this study, of which 29 identified as male and 11 as female. The average age was 31.3 years (range 16 to 57 years) and the mean follow-up time was 16.8 months (range 12 to 30 months). All functional outcome scores showed improvement over the course of the follow-up: Lysholm score 94.2 to 95.5 (n.s.), IKDC score 90.1 to 93.9 (n.s.), Tegner activity scale 3.7 to 5.0 (p > 0.001), all at six months and ≥12 months. No reruptures happened during the time of the follow-up. Conclusions: This study shows that the all-soft-tissue quadriceps tendon autograft technique can improve functional outcome in young and athletic patients with an ACL injury at short to intermediate follow-up.

Reliability of the MOCART (Magnetic Resonance Observation of Cartilage Repair Tissue) 2.0 knee score for different cartilage repair techniques-a retrospective observational study.

OBJECTIVES: To evaluate the reliability of the MOCART 2.0 knee score in the radiological assessment of repair tissue after different cartilage repair procedures. METHODS: A total of 114 patients (34 females) who underwent cartilage repair of a femoral cartilage lesion with at least one postoperative MRI examination were selected, and one random postoperative MRI examination was retrospectively included. Mean age was 32.5 ± 9.6 years at time of surgery. Overall, 66 chondral and 48 osteochondral lesions were included in the study. Forty-eight patients were treated with autologous chondrocyte implantation (ACI), 27 via osteochondral autologous transplantation, five using an osteochondral scaffold, and 34 underwent microfracture (MFX). The original MOCART and MOCART 2.0 knee scores were assessed by two independent readers. After a minimum 4-week interval, both readers performed a second reading of both scores. Inter- and intrarater reliabilities were assessed using intraclass correlation coefficients (ICCs). RESULTS: The MOCART 2.0 knee score showed higher interrater reliability than the original MOCART score with an ICC of 0.875 versus 0.759, ranging from 0.863 in the MFX group to 0.878 in the ACI group. Intrarater reliability was good with an overall ICC of 0.860 and 0.866, respectively. Overall, interrater reliability was higher for osteochondral lesions than for chondral lesions, with ICCs of 0.906 versus 0.786. CONCLUSIONS: The MOCART 2.0 knee score enables the assessment of cartilage repair tissue after different cartilage repair techniques (ACI, osteochondral repair techniques, MFX), as well as for different lesion types with good intra- and interrater reliability. KEY POINTS: • The MOCART 2.0 knee score provides improved intra- and interrater reliability when compared to the original MOCART score. • The MOCART 2.0 knee score enables the assessment of cartilage repair tissue after different cartilage repair techniques (ACI, osteochondral repair techniques, MFX) with similarly good intra- and interrater reliability. • The assessment of osteochondral lesions demonstrated better intra- and interrater reliability than the assessment of chondral lesions in this study.

Propranolol Is an Effective Topical and Systemic Treatment Option for Experimental Epidermolysis Bullosa Acquisita.

Propranolol is an ADRB2 blocker that regulates heart muscle contractions, smooth muscle relaxation, and glycogenolysis. In addition, an increasing number of applications in dermatology have been described, most prominently, the use as a first-line treatment for infantile hemangiomas. We here show that propranolol enhances IL-8-induced neutrophil chemotaxis and reduces the release of ROS after immune complex stimulation. To obtain further molecular insights into the modulatory effects of propranolol in activated neutrophils, we performed RNA sequencing of immune complex-stimulated neutrophils in the absence and presence of the drug. We identified the transcriptomic signature of propranolol and demonstrated an ADR2-independent immunomodulatory effect. To determine if the anti-inflammatory transcriptomic signature of propranolol also translates into clinical effects, we next evaluated the impact of propranolol in a prototypical neutrophil-dependent skin disease, specifically, antibody transfer-induced epidermolysis bullosa acquisita in mice. To validate the identified propranolol gene signature obtained in human neutrophils, we analyzed a selection of genes by RT-PCR in mouse epidermolysis bullosa acquisita skin and confirmed TNF, among others, to be differentially regulated by propranolol treatment. Our data clearly indicate that, based on its molecular impact on immune complex-activated neutrophils, propranolol is a potential treatment option for neutrophil-mediated inflammatory skin diseases.

Disinfection of contaminated metal implants with an Er:YAG laser.

Infections related to orthopedic procedures are considered particularly severe when implantation materials are used, because effective treatments for biofilm removal are lacking. In this study, the relatively new approach for infection control by using an erbium:yttrium-aluminum-garnet (Er:YAG) laser was tested. This laser vaporizes all water containing cells in a very effective, precise, and predictable manner and results in only minimal thermal damage. For preliminary testing, 42 steel plates and 42 pins were seeded with mixed cultures. First, the minimally necessary laser energy for biofilm removal was determined. Subsequently, the effectiveness of biofilm removal with the Er:YAG laser and the cleansing of the metal implants with octenidine-soaked gauze was compared. Then, we compared the effectiveness of biofilm removal on 207 steel pins from 41 patients directly after explantation. Sonication and scanning electron microscopy were used for analysis. Laser fluences exceeding 2.8 J/cm2 caused a complete extinction of all living cells by a single-laser impulse. Cleansing with octenidine-soaked gauze and irradiation with the Er:YAG laser are both thoroughly effective when applied to seeded pins. In contrast, when explanted pins with fully developed biofilms were analyzed, we found a significant advantage of the laser procedure. The Er:YAG laser offers a secure, complete, and nontoxic eradication of all kinds of pathogens from metal implants without damaging the implant and without the possible development of resistance. The precise noncontact removal of adjacent tissue is a decisive advantage over conventional disinfectants. Therefore, laser irradiation could become a valuable method in every debridement, antibiotics, and implant retention procedure.

The impact of nonosteogenic factors on the expression of osteoprotegerin and RANKL during human fracture healing.

OBJECTIVES: The osteoprotegerin (OPG) and receptor activator of nuclear factor kappa-B ligand (RANKL) balance is of the utmost importance in fracture healing. The aim of this study was therefore to investigate the impact of nonosteogenic factors on OPG and RANKL levels. METHODS: Serum obtained from 51 patients with long bone fractures was collected over 48 weeks. The OPG and serum sRANKL (soluble RANKL) concentrations were measured using enzyme-linked immunosorbent assay (ELISA). Smoking habit, diabetes, and alcohol consumption were recorded. RESULTS: Age and sex greatly influenced preoperative serum levels of OPG and sRANKL but differences were even more pronounced during fracture healing. Statistical significance was observed for overall serum levels of OPG (p = 0.001) and sRANKL (p < 0.001) in older men and women (age greater than 50 years). Interestingly, OPG levels increased over time in older women but decreased over time in older men. CONCLUSION: These data suggest that nonosteogenic factors, most significantly age and sex, have a major impact on sRANKL and OPG levels. Given the established association of OPG and sRANKL levels and nonunion, these findings seem to be of clinical relevance.Cite this article: J. Starlinger, G. Kaiser, A. Thomas, K. Sarahrudi. The impact of nonosteogenic factors on the expression of osteoprotegerin and RANKL during human fracture healing. Bone Joint Res 2019;8:349-356. DOI: 10.1302/2046-3758.87.BJR-2018-0116.R3.

Are OPG and RANKL involved in human fracture healing?

Human fracture healing is a complex interaction of several cytokines that regulate osteoblast and osteoclast activity. By monitoring OPG (osteoprotegerin) and sRANKL we aimed to possibly predict normal or impaired fracture healing. In 64 patients with a fracture of a long bone serum level of sRANKL and OPG were evaluated with respect to bony union (n=57) or pseudarthrosis (n=7). Measurements were carried out at admission and at 1, 2, 4, 6, 8, 12, 24, and 48 weeks after the injury. Patients' serum levels were compared to 33 healthy controls. Fracture hematoma contained significantly higher sRANKL and OPG concentrations compared to patients serum (p=0.005, p=0.028). OPG level in fracture hematoma was higher compared to the unions serum level (p=0.028). sRANKL was decreased in unions during the observation period. In non-unions sRANKL and OPG levels showed a variable course, with no statistical significance. This is the first study to document the course of OPG and sRANKL in normal and delayed human fracture healing emphasizing its local and systemic involvement. We provide evidence of strongly enhanced OPG levels in patients with a long bone fracture compared to healthy controls. Further, levels of free sRANKL were decreased during regular fracture repair.

Is the expression of Transforming Growth Factor-Beta1 after fracture of long bones solely influenced by the healing process?

PURPOSE: Circulating TGF-ß1 levels were found to be a predictor of delayed bone healing and non-union. We therefore aimed to investigate some factors that can influence the expression of TGF-ß1. The correlation between the expression of TGF-ß1 and the different socio-demographic parameters was analysed. METHODS: Fifty-one patients with long bone fractures were included in the study and divided into different groups according to their age, gender, cigarette smoking status, diabetes mellitus and regular alcohol intake. TGF-ß1 levels were analysed in patient's serum and different groups were retrospectively compared. RESULTS: Significantly lower TFG-ß1 serum concentrations were observed in non-smokers compared to smokers at week 8 after surgery. Significantly higher concentrations were found in male patients compared to females at week 24. Younger patients had significantly higher concentrations at week 24 after surgery compared to older patients. Concentrations were significantly higher in patients without diabetes compared to those with diabetes at six weeks after surgery. Patients with chronic alcohol abuse had significantly higher concentrations compared to those patients without chronic alcohol abuse. CONCLUSION: TGF-ß1 serum concentrations vary depending upon smoking status, age, gender, diabetes mellitus and chronic alcohol abuse at different times and therefore do not seem to be a reliable predictive marker as a single-point-in-time measurement for fracture healing.

The influence of low molecular weight heparin on the expression of osteogenic growth factors in human fracture healing.

PURPOSE: Anticoagulant therapy with low molecular weight heparins (LMWH) and mechanical compression is considered the gold standard for the prevention of thrombosis. However, evidence exists that LMWHs impair bone metabolism. The aim of this study was therefore to analyse alterations in the expression of M-CSF, VEGF and TGF-ß1 after treatment with enoxaparin in patients with long bone fracture to investigate the effect of LMWH on human fracture healing. METHODS: A total of 81 patients with long bone fractures were included in the study and divided into two groups. One group comprised patients who received enoxaparin and the other group, patients who did not receive enoxaparin postoperatively. Growth factor levels were analysed in patients' serum and different groups were retrospectively compared. RESULTS: M-CSF serum concentrations were found to be significantly higher only at 48 weeks after surgery in enoxaparin. Mean overall VEGF serum concentration was higher in patients with enoxaparin. TGF-ß1 serum concentrations were higher at 48 weeks after surgery in patients with enoxaparin. CONCLUSION: This is the first comparative systemic measurement of M-CSF, VEGF and TGF-ß1 serum levels in patients with and without enoxaparin after long bone fracture. Significant differences of the expression of the growth factors after enoxaparin therapy were only observed at week 48 after surgery for M-CSF and TGF-ß1.

Elevated transforming growth factor-beta 1 (TGF-ß1) levels in human fracture healing.

INTRODUCTION: Transforming growth factor-beta 1(TGF-ß1) is a regulatory protein, involved in bone fracture healing. Circulating TGF-ß1 levels have been reported to be a predictor of delayed bone healing and non-union, suggesting active relationship between tissue and circulating TGF-ß1 in fracture healing. The purpose of this study was to analyse TGF-ß1 local and serum concentrations in fracture healing to further contribute to the understanding of molecular regulation of fracture healing. PATIENTS AND METHODS: Serum samples of 113 patients with long bone fractures were collected over a period of 6 months following a standardised time schedule. TGF-ß1 serum concentrations were measured using ELISA. Patients were assigned to 2 groups: Group 1 contained 103 patients with physiological healing. Group 2 contained 10 patients with impaired healing. Patients in both groups were matched. One patient of the group 2 had to be excluded because of missing match partner. In addition, fracture haematoma from 11 patients of group 1 was obtained to analyse local TGF-ß1 concentrations. 33 volunteers donated serum which served as control. RESULTS: TGF-ß1 serum concentrations increased during the early healing period and were significantly higher in patients with physiological healing compared to controls (P=0.04). Thereafter, it decreased continuously between weeks 2 and 8 and fell again after week 8. TGF-ß1 serum concentrations in patients with physiological healing were significantly higher at week 24 compared to controls (P=0.05). In non-unions, serum concentrations differed significantly from those of controls at week 6 (P=0.01). No significant difference in between patients with physiological and impaired fracture healing was observed. Fracture haematoma contained significantly higher TGF-ß1 concentrations than peripheral serum of the patients (P=0.017). CONCLUSION: Elevated levels of TGF-ß1 in haematoma and in serum after bone fracture especially during the entire healing process indicate its importance for fracture healing.