[Refracture of long bones after implant removal. An avoidable complication?]

Evidence on treatment of clavicle fractures

Depending on the severity of the injury and the involvement of the soft tissue envelope, clavicle fractures can be treated operatively or non-operatively. In the past, displaced fractures of the clavicle shaft in adults have been treated non-operatively. However, the rate of nonunion following non-operative treatment seems to be higher than previously reported. In addition, publications reporting better functional outcomes following operative treatment are increasing. In recent years this has led to a paradigm shift towards an increase of operative fracture treatment. The aim of this review article was to summarize the currently available evidence on the treatment of clavicle fractures. Classifications, indications, and treatment options for different fracture patterns of the medial, midshaft, and lateral clavicles are presented and discussed.

Reduced Cell Adhesion on LightPLAS-Coated Implant Surfaces in a Three-Dimensional Bioreactor System

Most implants used in trauma surgery are made of steel and remain inside the body only temporarily. The strong tissue interaction of such implants sometimes creates problems with their explantation. Modified implant surfaces, which decrease tissue attachment, might allow an easier removal and therefore a better outcome. Such a modification must retain the implant function, and needs to be biocompatible and cost-effective. Here, we used a novel VUV-light (Vacuum-Ultraviolett)-based coating technology (LightPLAS) to generate coated stainless-steel plates. The tested LightPLAS coating only had an average thickness of around 335 nm, making it unlikely to interfere with implant function. The coated plates showed good biocompatibility according to ISO 10993-5 and ISO 10993-12, and reduced cell adhesion after four different time points in a 2D cell culture system with osteoblast-like MG-63 cells. Furthermore, we could show decreased cell adhesion in our 3D cell culture system, which mimics the fluid flow above the implant materials as commonly present in the in vivo environment. This new method of surface coating could offer extended options to design implant surfaces for trauma surgery to reduce cell adhesion and implant ingrowth. This may allow for a faster removal time, resulting in shorter overall operation times, thereby reducing costs and complication rates and increasing patient wellbeing.

Refracture after plate removal of midshaft clavicle fractures after bone union-incidence, risk factors, management and outcomes

INTRODUCTION

There is a great debate on the routine use of open reduction and internal fixation (ORIF) for midshaft clavicle fractures, and one concern is the adverse events after ORIF, such as implant removal after bone union. In this retrospective study, we assessed the incidence, risk factors, management and outcomes of refracture after plate removal of midshaft clavicle fractures after bone union.

MATERIALS AND METHODS

Three hundred fifty-two patients diagnosed with acute midshaft clavicle fractures who had complete medical records from primary fractures to refracture were recruited. Details of imaging materials and clinical characteristics were carefully reviewed and analysed.

RESULTS

The incidence rate of refracture was 6.5% (23/352), and the average interval from implant removal to refracture was 25.6 days. Multivariate analysis showed that the risk factors were Robinson type-2B2 and fair/poor reduction. Females were 2.4 times more likely to have refracture, although it was not significant in multivariate analysis (p = 0.134). Postmenopausal females with a short interval (≤ 12 months) from primary surgery to implant removal had a significant risk for refracture. Tobacco use and alcohol use during bone healing were potential risk factors for male patients, although they were not significant in multivariate analysis. Ten patients received reoperation with or without bone graft, and they had a higher rate of bone union than 13 patients who refused reoperation.

CONCLUSION

The incidence of refracture following implant removal after bone union is underestimated, and severe comminute fractures and unsatisfactory reduction during primary surgery are risk factors. Implant removal for postmenopausal female patients is not recommended due to a high rate of refracture.

The Application of an Allogenic Bone Screw for Stabilization of a Modified Chevron Osteotomy: A Prospective Analysis

Background: Distal first metatarsal osteotomies are commonly performed operative procedures for hallux valgus deformity, and usually involve fixation with a metal screw. However, various bioabsorbable osteosynthesis materials have been in use for a number of years. One recent innovation is the Shark Screw®, a human cortical bone allograft. This study aimed to evaluate the efficacy and safety of this allogeneic screw in the stabilization of Reversed L-Shaped osteotomy, a modified Chevron osteotomy. Methods: In a prospective study, 15 patients underwent a Reversed L-Shaped osteotomy stabilized with the allogenic bone screw Radiological data on osteointegration of the screw and correction of the intermetatarsal angle were recorded. Furthermore, each follow-up examination included the collection of clinical data, the American Orthopedic Foot and Ankle Society (AOFAS) score, evaluation of pain level, and patient’s overall satisfaction. Results: Full osseous fusion of the osteotomy was seen in all patients. The bone screws were radiographically integrated after approximately 6.5 (±2.6) months. Neither nonunion nor failure occurred in any of our cases. Furthermore, we did not find any potential graft reaction. The AOFAS score improved significantly from 51.6 (±15.2) points to 90.9 (±10.3) (p < 0.001). The preoperative hallux valgus angle and intermetatarsal angle decreased significantly from 24.8 (±4.9) degrees to 7.2 (±4.4) degrees (p < 0.001) and 12.6 (±3.2) degrees to 4.8 (±1.3) degrees (p < 0.001), respectively. Conclusions: With this study, we demonstrated the efficiency of the allogenic bone screw (Shark Screw®) in regard to clinical and radiological short-term outcomes.

Laser Ablated Periodic Nanostructures on Titanium and Steel Implants Influence Adhesion and Osteogenic Differentiation of Mesenchymal Stem Cells

Metal implants used in trauma surgeries are sometimes difficult to remove after the completion of the healing process due to the strong integration with the bone tissue. Periodic surface micro- and nanostructures can directly influence cell adhesion and differentiation on metallic implant materials. However, the fabrication of such structures with classical lithographic methods is too slow and cost-intensive to be of practical relevance. Therefore, we used laser beam interference ablation structuring to systematically generate periodic nanostructures on titanium and steel plates. The newly developed laser process uses a special grating interferometer in combination with an industrial laser scanner and ultrashort pulse laser source, allowing for fast, precise, and cost-effective modification of metal surfaces in a single step process. A total of 30 different periodic topologies reaching from linear over crossed to complex crossed nanostructures with varying depths were generated on steel and titanium plates and tested in bone cell culture. Reduced cell adhesion was found for four different structure types, while cell morphology was influenced by two different structures. Furthermore, we observed impaired osteogenic differentiation for three structures, indicating reduced bone formation around the implant. This efficient way of surface structuring in combination with new insights about its influence on bone cells could lead to newly designed implant surfaces for trauma surgeries with reduced adhesion, resulting in faster removal times, reduced operation times, and reduced complication rates.

Current State of Bone Adhesives-Necessities and Hurdles

The vision of gluing two bone fragments with biodegradable and biocompatible adhesives remains highly fascinating and attractive to orthopedic surgeons. Possibly shorter operation times, better stabilization, lower infection rates, and unnecessary removal make this approach very appealing. After 30 years of research in this field, the first adhesive systems are now appearing in scientific reports that may fulfill the comprehensive requirements of bioadhesives for bone. For a successful introduction into clinical application, special requirements of the musculoskeletal system, challenges in the production of a bone adhesive, as well as regulatory hurdles still need to be overcome. In this article, we will give an overview of existing synthetic polymers, biomimetic, and bio-based adhesive approaches, review the regulatory hurdles they face, and discuss perspectives of how bone adhesives could be efficiently introduced into clinical application, including legal regulations.

Development of magnesium implants by application of conjoint-based quality function deployment

Biodegradable magnesium-based implants are the subject of a great deal of research for different orthopedic and vascular applications. The targeted design and properties depend on the specific medical function and location in the body. Development of the biomaterial requires a comprehensive understanding of the biological interaction between the implant and the host tissue, as well as of the behavior in the physiological environment in vivo. Research into and the development of innovative magnesium implants entails interdisciplinary research efforts and communication between materials science, bioscience, and medical experts. The present study provides a transparent planning and communication tool for market-oriented implant development processes. The objective was to identify medical needs at an early stage of the development process and to quantify the importance of the engineering characteristics of different research fields that cater to specific implant requirements. The method is demonstrated by the performance of a survey-based conjoint analysis, which was integrated into a quality function deployment approach. Twenty-seven medical professionals and 29 biomaterial scientists assessed the importance of identified medical requirements, whereby the control of mechanical integrity and degradation along with nontoxicity and nonimmunogenicity showed the highest number of preferences. The evaluation of implant options by 31 experts indicated that the engineering characteristic with the highest importance was the condition and sterilization of the surface. These values can be used to set priorities in strategic decisions. Research trials can be aligned to medical preferences, ensuring high product quality and an effective development process. This is the first paper to report on the application of conjoint-based quality function deployment in biomaterial research.

A novel implant removal technique by endoscopy

BACKGROUND

Routine implant removal after fracture healing remains controversial. However, it has been suggested that implant removal should be performed in cases of joint impingement, painful scar adhesion, and implant malposition. Entrance selection is relatively critical in patients with poor soft tissue conditions or sloughing coverage. We propose an innovative technique using endoscopy.

METHODS

Consecutive surgeries of endoscopic implant removal performed between 2005 and 2016 by a single experienced arthroscopic surgeon were included. Overall, 73 patients were enrolled; 44 were not eligible for inclusion and were excluded from the study.

RESULTS

Twenty-nine patients, including 32 surgical sites, were included. Twenty-four plates and 166 screws were removed using this technique. There were five complications during the follow-up period (range, 0.5 to 104 months; mean, 8.8), including one broken screw, one persistent knee joint contracture, and three wound dehiscence. There were no infections or neurovascular injuries.

CONCLUSION

Implant removal using endoscopy is a minimally invasive surgery that ensures that the screw axis does not strip, and treats the intra-articular pathology concomitantly. This innovative technique may be considered as an alternative to the traditional open method in cases with good surgical indications.

[Fractures of the lower extremities in childhood : Part 1: fractures of the thigh and in the proximity of the knee]

Fractures in children are a major challenge in everyday clinical practice. The decision about the correct treatment of fractures follows the consideration of individual factors. The age of the child and the resulting residual growth play an essential role. This article aims to facilitate a structured approach with respect to examination, diagnostics and treatment in clinical practice. This first part of this series deals with fractures of the thigh and in the proximity of the knee joint in children. The peculiarity of pediatric bone lies in its growth, which results not only in a much faster healing tendency than in adults but also possesses a greater correction potential. It is therefore very important for fracture healing to include the tolerance limits for existing axis misalignment as well as the expected spontaneous correction potential and the resulting remodeling in the therapy decision. The various operative measures must be used in a targeted manner. Incongruencies of joints as well as significant length differences should be avoided.

Complications during removal of conventional versus locked compression plates: is there a difference?

BACKGROUND

Osteosynthesis plate removal is one of the most commonly performed procedures in orthopaedic surgery. Due to technological advances and the quality of increasing osteosynthesis material, more and more locked plates have been implanted over the last 20 years. The aim of this study was to determine whether the complication rate during plate removal differs between conventional and locked plates.

MATERIAL AND METHODS

In this retrospective cohort study, 620 patients were included and divided into two groups based on the type of plate (locked and conventional). Technical complications during implant removal included screw breakage, destroyed screw head, implant breakage, remaining implant material, refracture, bony or soft tissue overgrowth. The following plate-associated complications were identified: osteosynthesis plate not detachable, plate bent or broken, necessity of special tools or plate loosened. Three types of screw-related complications were observed: screw not detachable, screw broken or screw dislocated.

RESULTS

Overall, complications related to the plate or screws were documented in 110 of the 620 cases. These complications occurred in 48 of the 382 cases involving conventional osteosynthesis (7.7% of all removals, 12.6% of all conventional removals) and in 62 of the 238 cases involving locked plate osteosynthesis (10.0% of all removals, 26.1% of all locked plate removals). The statistical analysis showed a significantly higher implant-related complication rate with locked plates compared to the conventional plates (p < 0.01).

CONCLUSIONS

Hardware removal can be a complication-afflicted operation, especially cases involving locked-plate removal should only be performed if a strong indication is evident. Possible benefits of the procedure should be considered carefully, taking the cost-benefit ratio into account.

The Impact of Psychological Factors on Device Removal Surgery

Background

Implant removal is a common procedure in orthopedic surgery which can be associated with many complications such as scar formation, hematoma, nerve injury, infection, and refracture. Indications for orthopedic implant removal have declined in recent years. Most studies have considered orthopedic hardware removal as an unnecessary procedure in the absence of severe complications such as nonunion. Some studies have reported the complications of orthopedic hardware removal to be 24% to 50% dependent on their types and locations as well as on other factors such as patient’s condition and the orthopedist’s experience.

Objectives

The present study surveyed possible mental and psychological causes among patients who asked for removal procedures in spite of orthopedic surgeons’ advice and being aware of complications.

Patients and Methods

Patients who had undergone plating for the treatment of radius and ulna fractures from 2011 to 2013, were told that it is not necessary to remove the plate and they were warned of all the risks of removal surgery, such as anesthesia, possible nerve or vascular damage, and the cost of surgery. Then, their tendency to remove the plate was examined based on evaluation criteria scores. Patients were divided into two groups: patients who insisted on surgery despite all the risks and patients who had little tendency or gave up after explanations. Both groups were given visual analog pain scale (VAS), symptom checklist-90 (SCL-90), and pain catastrophizing scale (PCS) questionnaires. The questions were explained for patients by an expert trained in the clinic and in case of ambiguity further explanations were given to the patients. The data were then entered into statistical package for the social science (SPSS) version 20 for analysis.

Results

A total of 29 patients with plates were enrolled. The first group consisted of 16 male and 13 female patients. In the control group (group II), there were 30 patients with no tendency for plate removal. In this group, 15 patients were male and 15 were female. The mean age of the first group was 38.25 ± 11.12 years and for the second group it was 36.82 ± 12.01 years. There was no significant difference between the two groups in terms of age and gender. Mean discomfort of patients was 7.75 ± 1.74 in the first and 3.96 ± 1.90 in the second group, indicating a statistically significant difference (P = 0.000). Mean VAS score was 3.96 ± 1.20 in the first group and 3.80 ± 1.15 in the second group, which was not statistically significant (P = 0.593). Mean daily pain and discomfort was 10.62 ± 3.09 hours in the first and 4.86 ± 2.23 hours in the control group, indicating a statistically significant difference (P = 0.000). Linear regression analysis results demonstrated a significant correlation between increased VAS scores in the first group (P = 0.000), but it was not significant in the second group (P = 0.083). The results also showed that increase in time of daily pain and discomfort had a linear relationship with increased discomfort score in both groups (P = 0.00). Mean pain catastrophizing scale (PCS) score was 10.13 ± 3.62 in the first and 9.56 ± 3.07 in the second group, which was not statistically significant. Mean somatization score was 52% ± 6.53% and 47.96% ± 7.17% in the first and second groups, respectively, which showed no significant differences (P = 0.013). Obsessive compulsive score was 54.63 ± 5.34 in the first and 46.63 ± 4.49 in the second group, which was statistically significant (P = 0.000).

Conclusions

Mental and psychological backgrounds can affect the severity of discomfort of the implant. Given that so far the present study is the only study investigating the relationship between mental criteria and tendency of patients for implant removal, further studies with larger sample sizes seem warranted.

Metal implant removal: benefits and drawbacks--a patient survey

BACKGROUND

Hardware removals are among the most commonly performed surgical procedures worldwide. Current literature offers little data concerning postoperative patient satisfaction. The purpose of our study was to evaluate the patients' point of view on implant removal.

METHODS

We surveyed patients of a German level one trauma center, who underwent hardware removal in 2009 and 2010, with regard to their personal experiences on implant removal. Exclusively, data obtained out of the survey were analyzed.

RESULTS

In 332 patients surveyed, most hardware removals were performed at the ankle joint (21%) followed by the wrist (15%). The most frequent indication was a doctor's recommendation (68%), followed by pain (31%) and impaired function (31%). Patient reported complication rate of implant removal was 10%. Importantly, after implant removal because of pain or impaired function patients reported an improvement in function (72%) as well as decreased pain (96%). 96% of all responding patients and 66% of the patients who suffered from subsequent complications would opt for surgical implant removal again.

CONCLUSION

In summary, despite the challenging and frequently troublesome nature of surgical hardware removal our data contradicts the widely held view that implant removal is often without a positive effect on the patients. These findings may influence the surgeons' attitude towards implant removal and their day-to-day routine in patient counseling.

Biomechanical analysis of subpectoral biceps tenodesis: effect of screw malpositioning on proximal humeral strength

BACKGROUND

Humeral fracture after subpectoral tenodesis of the long head of biceps tendon (LHB) is a rare but devastating complication.

PURPOSE

To determine whether malpositioned (laterally eccentric) tenodesis screw placement has an influence on humerus strength reduction compared with central placement.

STUDY DESIGN

Controlled laboratory study.

METHODS

Two groups, each consisting of 10 matched pairs of human humeri, were used for this study. Biceps tendons were fixed subpectorally with 8-mm screws in unicortical 8-mm sockets. In the first group, the socket was placed concentrically in the bicipital groove and the tendon was fixed with an interference screw. In the second group, the socket was malpositioned 30% eccentrically to the lateral (tension) side of the humerus. Contralateral humeri remained intact as positive controls. Specimens were aligned in 40° of abduction, and a uniaxial compressive force was applied to the humeral head until failure. Strength reduction was reported as percentage reduction in ultimate failure load between paired humeri. Relative defect size was calculated as a percentage of the total humeral width at the height of the tenodesis.

RESULTS

Laterally eccentric malpositioned biceps tenodeses significantly decreased humeral strength compared with intact (mean change, -25%; SD, 23%; P=.017), while concentrically placed biceps tenodeses did not (mean change, -10%; SD, 15%; P=.059). A linear regression between relative defect size and strength reduction in the malpositioned group showed a significant negative linear correlation (beta=-2.577; R2=0.423; P=.042).

CONCLUSION

Humeral fracture after subpectoral tenodesis of the LHB is a complication that may be minimized with careful surgical technique. Laterally eccentric malpositioned biceps tenodesis caused significant reduction (25%) in humeral strength, which might be clinically relevant and contribute to postsurgical humeral shaft fracture. Strength reduction was also significantly correlated with relative defect size. Surgeons using this technique should ensure central and orthogonal placement of the socket, especially in smaller individuals. This study lends biomechanical evidence to support the clinical procedure of a correctly, concentrically placed tenodesis screw.

CLINICAL RELEVANCE

These biomechanical results indicate that in a clinical setting, special attention should be drawn to patient selection for LHB tenodesis. This study reveals that central screw positioning is critical, particularly in high-impact and overhead athletes, as well as for patients with small humeral widths or osteoporotic bone quality. Alternative surgical options such as smaller screws or other fixation methods might be considered to diminish the postoperative risk of humeral fracture.

Numerical simulation of callus healing for optimization of fracture fixation stiffness

The stiffness of fracture fixation devices together with musculoskeletal loading defines the mechanical environment within a long bone fracture, and can be quantified by the interfragmentary movement. In vivo results suggested that this can have acceleratory or inhibitory influences, depending on direction and magnitude of motion, indicating that some complications in fracture treatment could be avoided by optimizing the fixation stiffness. However, general statements are difficult to make due to the limited number of experimental findings. The aim of this study was therefore to numerically investigate healing outcomes under various combinations of shear and axial fixation stiffness, and to detect the optimal configuration. A calibrated and established numerical model was used to predict fracture healing for numerous combinations of axial and shear fixation stiffness under physiological, superimposed, axial compressive and translational shear loading in sheep. Characteristic maps of healing outcome versus fixation stiffness (axial and shear) were created. The results suggest that delayed healing of 3 mm transversal fracture gaps will occur for highly flexible or very rigid axial fixation, which was corroborated by in vivo findings. The optimal fixation stiffness for ovine long bone fractures was predicted to be 1000–2500 N/mm in the axial and >300 N/mm in the shear direction. In summary, an optimized, moderate axial stiffness together with certain shear stiffness enhances fracture healing processes. The negative influence of one improper stiffness can be compensated by adjustment of the stiffness in the other direction.

Technical complications during removal of locking screws from locking compression plates: a prospective multicenter study

PURPOSE

To assess the risk for technical complications in patients undergoing removal of locking compression plates (LCP) with head locking screws.

METHODS

A total of 205 patients who were scheduled for implant removal surgery after a healed fracture of the femur, tibia, humerus, distal radius, or clavicle in nine Austrian clinics were prospectively included in the study, all of whom had previously undergone fracture fixation by plates, with titanium implants used in 98 % of the patients. Intraoperative technical complications and the methods used to solve them were documented by the surgeon.

RESULTS

During the course of this study, a total of 1,462 locking screws were removed from 204 LCPs. While 95 % of these screws could be removed without difficulties, technical complications were reported for 41 patients with 78 screws which could not be removed with standard screwdrivers and required the use of additional instruments. The estimated risk for the occurrence of at least one technical complication during implant removal surgery was 20.1 %. The most frequently observed complications were screws that could not be loosened because they were jammed in the LCP, screws with a damaged recess in which the screwdriver turned freely, as well as a combination of both events. The majority of these screws could be removed with the use of a conical extraction screw or by drilling off the screw head. In one patient, an intraoperative refracture of the humerus occurred during plate removal. Even though there is a rate of 20 % for technical complications when removing the implants, only a few patients experience a clinical impact.

CONCLUSIONS

Titanium LCPs are prone to technical complications during implant removal, but the majority of the issues can be solved using special techniques.