Background: Delayed fracture healing continues to cause significant patient morbidity and an economic burden to society. Biological stimulation of non-unions includes application of recombinant bone morphogenetic protein-2 (rhBMP-2). However, rhBMP-2 use continues to be a matter of controversy as literature shows scarce evidence for treatment effectiveness. Questions: The objective of this study was to evaluate the effectiveness of rhBMP-2 treatment on long bone non-unions measuring union rate and time to union. Furthermore, we assess risk factors for treatment failure. Methods and patients: A total of 91 patients with non-unions of long bones were treated with rhBMP-2 (n = 72) or standard care without BMP (n = 19) at our institution. Patient characteristics, comorbidities, nicotine consumption, and complications were recorded. Bone healing was assessed by plane X-rays and clinical examination. Patients were followed up with for 24 months. Results: Overall, there was significantly faster bone healing after rhBMP-2 application compared to the no-BMP group (p < 0.001; HR = 2.78; 95% CI 1.4–5.6). Union rates differed significantly between rhBMP-2 compared to the no-BMP group (89% vs. 47%; p < 0.001). At the humerus, there was neither a significantly higher union rate in the rhBMP-2 (83%) compared to the no-BMP group (50%) (p = 0.26; n = 12) nor a faster bone healing with a median time of 9 months in both groups (HR = 2.01; 95% CI 0.49–8.61; p = 0.315). The 33 femora treated using rhBMP-2 healed significantly faster than 9 femora in the no-BMP group (HR = 2.93; 95% CI 1.00–8.4; p = 0.023) with significant differences in union rate with 85% and 44%, respectively (p = 0.022). Regarding tibia non-unions, 25 out of 27 (93%) healed with a median of 9 months after rhBMP-2 application with no significant difference in the no-BMP group (33%) in time to union (p = 0.097) but a significantly higher union rate (p = 0.039). There was no effect of comorbidities, age, sex, soft tissue damage, or nicotine use on time to union, union rate, or secondary interventions. Conclusion: Consistent with the literature, overall, significantly higher union rates with reduced time to union were achieved after rhBMP-2 application. Femoral and tibial non-unions in particular seem to profit from rhBMP-2 application.

Fractures of the scapular spine are relatively rare and can occur without (1) or with (2) association to a reverse shoulder arthroplasty (RSA). To date there are only limited data on the topic. The aim of this scoping review was to identify all available literature and report current treatment concepts. A scoping review was conducted by searching PubMed for relevant studies between 2000 and October 2020. All studies were included which gave detailed descriptions of the treatment strategy. A total of 21 studies with 81 patients were included for the analysis. The mean age over all patients was 62 years (range: 24 to 89 years) and 77% of the patients were female. In 19.8% of cases, the fracture occurred after a traumatic fall from standing height. Eighty-six per cent of the patients had an RSA-associated scapular spine fracture (2). These patients were older compared to group (1) (47 ± 19.6 vs. 76 ± 5.6 years, p = 0.0001) and the majority were female (85%). The majority from group (1) underwent operative treatment with plate fixation. Most patients regained full function and range of motion. RSA-associated fractures (2) were mainly treated non-operatively, with moderate clinical outcome. A high rate of nonunions was reported. Scapular spine fractures without RSA are mainly treated operatively with good clinical results. In association with RSA, scapular spine fractures are mainly treated non-operatively and lead to inferior clinical and radiological results. This scenario seems to be problematic and further research is required to sharpen treatment concepts in this group. Cite this article: EFORT Open Rev 2021;6:788-796. DOI: 10.1302/2058-5241.6.200153

Double plating for proximal humeral fractures (PHF) is an option to increase the primary fixation stability. Clinical data is missing for assessment of clinical and radiological outcome, as well as complications. We retrospectively examined 35 patients with unilateral PHF, who were treated with double plating for PHF between 2013 and 2019. The mean age was 59.5 ± 12 years and the leading fracture type was a varus dislocation (Resch type IV in 55.3%). A head-split was present in 22.9% of the cases. The primary outcome measurement was the radiological neck shaft angle (NSA). The radiological follow-up was 21 ± 16.6 months and the NSA did not differ between the intraoperative and follow-up time point (131.5 ± 6.9° vs. 136.6 ± 13.7°; p = 0.267). The clinical follow-up was 29.5 ± 15.3 months. The Constant-score was 78.5 ± 17 points, the simple-shoulder-test (SST) was 9.3 ± 3.2 points and the subjective shoulder value (SSV) was 78.8 ± 19.5%. The over-all complication rate was 31.4%, and without stiffness 14.3%. An avascular necrosis occurred in two patients (5.7%). In conclusion, this study shows good radiological and functional outcomes after double plating of highly complex proximal humeral fractures, while the complication rate is comparable to the literature. Double plating is a viable option especially for younger patients with complex fractures as a potential alternative to fracture arthroplasty.

Background: Animal models are one of the first steps in translation of basic science findings to clinical practice. For tendon healing research, transgenic mouse models are important to advance therapeutic strategies. However, the small size of the structures complicates surgical approaches, histological assessment, and biomechanical testing. In addition, available models are not standardized and difficult to compare. How surgery itself affects the healing outcome has not been investigated yet. The focus of the study was to develop a procedure that includes a transection and microsurgical reconstruction of the Achilles tendon but, unlike other models, preserves the sciatic nerve. We wanted to examine how distinct parts of the technique influenced healing. Methods: For this animal model study, we used 96 wild-type male C57BL/6 mice aged 8–12 weeks. We evaluated different suture techniques and macroscopically confirmed the optimal combination of suture material and technique to minimize tendon gap formation. A key element is the detailed, step-by-step illustration of the surgery. In addition, we assessed histological (Herovici and Alcian blue staining) outcome parameters at 1–16 weeks postoperatively. Microcomputed tomography (micro-CT) was performed to measure the bone volume of heterotopic ossifications (HOs). Biomechanical analyses were carried out using a viscoelastic protocol on the biomechanical testing machine LM1. Results: A modified 4-strand suture combined with a cerclage for immobilization without transection of the sciatic nerve reliably eliminated gap formation. The maximal dorsal extension of the hindlimb at the upper ankle joint from the equinus position (limited by the immobilization cerclage) increased over time postoperatively (operation: 28.8 ± 2.2°; 1 week: 54 ± 36°; 6 weeks: 80 ± 11.7°; 16 weeks: 96 ± 15.8°, p > 0.05). Histological staining revealed a maturation of collagen fibres within 6 weeks, whereas masses of cartilage were visible throughout the healing period. Micro-CT scans detected the development of HOs starting at 4 weeks and further progression at 6 and 16 weeks (bone volume, 4 weeks: 0.07604 ± 0.05286 mm³; 6 weeks: 0.50682 ± 0.68841 mm³; 16 weeks: 2.36027 ± 0.85202 mm³, p > 0.001). In-depth micro-CT analysis of the different surgical elements revealed that an injury of the tendon is a key factor for the development of HOs. Immobilization alone does not trigger HOs. Biomechanical properties of repaired tendons were greatly altered and remained inferior 6 weeks after surgery. Conclusion: With this study, we demonstrated that the microsurgical technique greatly influences the short- and longer-term healing outcome. When the sciatic nerve is preserved, the best surgical reconstruction of the tendon defect is achieved by a 4-strand core suture in combination with a tibiofibular cerclage for postoperative immobilization. The cerclage promotes a gradual increase in the range of motion of the upper ankle joint, comparable with an early mobilization rehabilitation protocol. HO, as a key mechanism for poor tendon healing, is progressive and can be monitored early in the model. The translational potential of this article The study enhances the understanding of model dependent factors of healing. The described reconstruction technique provides a reproducible and translational rodent model for future Achilles tendon healing research. In combination with transgenic strains, it can be facilitated to advance therapeutic strategies to improve the clinical results of tendon injuries.

In recent biomechanical studies, the importance of glenoid concavity and version for anterior shoulder stability has been highlighted. With this study, we aimed to assess their clinical relevance as stabilizing factors. We hypothesized that low glenoid concavity and low retroversion are associated with anterior glenohumeral instability. In this single-center, retrospective case-control study, computed tomography scans of n = 34 patients following acute anteroinferior glenohumeral dislocation between 2015 and 2021 were included. Patients with glenoid fractures and pre-existing glenohumeral pathologies were excluded. In the control group, n = 68 polytrauma patients referred to our level-I-trauma center were included, who showed neither acute nor chronic glenohumeral pathologies. Both groups were matched age- and gender-specifically in a 2:1 ratio. Glenoid concavity was measured according to the bony shoulder stability ratio (BSSR) in anterior-posterior (AP) and superior-inferior (SI) direction. Version was measured by the glenoid vault method. The instability cohort presented with a lower BSSR (SI) compared to the control group (49.8% vs. 56.9%, P = .001). The BSSR (AP) did not differ significantly (30.2% vs. 33.7%, P = .163). A higher retroversion was seen in the instability cohort (−13.1° vs. −11.4°; P = .041). Subgroup analyses showed higher BSSR (SI) in ≥60-year-old patients compared to ≤30-year-old patients. BSSR (AP) and glenoid version did neither differ age- nor gender-specifically. Glenoid concavity is a relevant factor for anterior shoulder stability in the clinical setting. In contrast to recent biomechanical studies, glenoid version appears to have only limited clinical impact on anterior stability. Regarding the individual treatment of anterior glenohumeral instability, glenoid concavity should be focused on as an essential bony stabilizing factor.