A retrospective follow-up of ankle fracture patients treated with a biodegradable plate and screws

The biointegration profile of fiber-reinforced plates following tibial implantation in sheep

Biointegrative, mineral fiber-reinforced bone fixation implants recently introduced in orthopedic surgery have expanded available treatment options for fractures and bone deformities. This new technology aims to address the disadvantages of permanent metallic implants while overcoming inherent concerns of adverse inflammatory reactions when using polymer-based orthopedic implants. The purpose of this double-arm preclinical study was to evaluate the safety, biocompatibility, and biointegration of fiber-reinforced plates, following implantation on the tibias of eight sheep. Left tibias underwent periosteal elevation, allowing for implant attachment directly onto the cortical surface; right tibia plates were implanted over intact periosteum. Microcomputed tomography and histopathology were performed at 13, 26, 52, 78, 104, and 134 weeks postimplantation. All animals were evaluated clinically at each time point, with no evidence of local adverse reactions. Histopathology demonstrated anti-inflammatory M2-like macrophages and multinucleated giant cells corresponding to implant bioabsorption, similar for both groups at each time point, and indicating expected implant biocompatibility. Inflammatory cells (i.e., eosinophils, lymphophyctes, plasma cells, and M1-like macrophages) were absent throughout the study. The bioabsorption process had started at 13 W, with the highest rate at 52-78 W. At 104 W, only residual polymer material was left (∼5% of implant area). Low amounts of mineral fibers were evident at 78 W and were absent (fully remodeled) by 104 W. At 134 W, implants at both sites were fully bioabsorbed. In conclusion, these new fiber-reinforced implants demonstrated bone remodeling and complete biointegration, with no adverse tissue response. Clinical significance: In this double-arm, 2.5-year study, a biointegrative, fiber-reinforced plate implanted on the tibias of sheep was fully absorbed within 134 weeks, with no adverse tissue reaction. Bioabsorption was similar, with or without periosteal elevation, mimicking conditions like those observed in traumatic injuries disrupting the periosteum, open reduction and internal fixation, or minimally invasive surgeries. These results demonstrate the feasibility, versatility, and safety of this new class of biointegrative bone implants. This newly developed technology avoids the complications of the removal of metal implants.

Are Absorbable Plates More Resistant to Infection Than Titanium Implants? An Experimental Pre-Clinical Trial in Rabbits

Background: Infection of orthopaedic implants after internal fixation of bone fractures remains a major complication with occasionally devastating consequences. Recent studies have reported that the use of absorbable materials, instead of metallic ones, may lead to a lower incidence of postoperative infection. In this experimental pre-clinical animal study, we compared the infection rate between absorbable implants consisting of copolymers composed from trimethylene carbonate, L-polylactic acid, and D, L-polylactic acid monomers, and titanium implants after the inoculation of a pathogenic microorganism. Material and Methods: We used an experimental implant-related infection model in rabbits. Sixty animals were randomly and equally divided into two groups. In all animals, the right femur was exposed via a lateral approach and a 2.5 mm two-hole titanium plate with screws (Group A), or a two-hole absorbable plate and screws (Group B), were applied in the femoral shaft. Afterwards, the implant surface was inoculated with Pseudomonas Aeruginosa at a concentration of 2 × 108 CFU/mL. The primary outcome was the comparison of the incidence of developed infection between the two groups. The wound condition was monitored on a daily basis and radiographies were obtained at 12 weeks postoperatively. Infection-related laboratory markers (white blood cell count, erythrocyte sedimentation rate, and C-reactive protein values) were assessed at 3, 6, and 16 weeks postoperatively. Histologic analysis and cultures of tissue samples were also performed to evaluate the presence of infection. Results: Clinical and laboratory signs of infection were evident in 11 rabbits in Group A (36.7%), and 4 in Group B (13.3%). The difference between the groups was statistically significant (p = 0.04). Five animals in Group B (16.7%) had clinical and histologic signs of a foreign-body reaction with significantly elevated CRP and ESR values but no simultaneous presence of infection was identified (p = 0.04). Bone remodelling with thickening of the periosteum and surrounding sclerosis was demonstrated radiologically in animals developing infection or foreign-body reactions. Conclusions: Absorbable plates and screws show lower susceptibility to infection compared to titanium ones. However, their application is associated with foreign-body reaction and the potential need for a second surgical intervention.

OUTCOMES AFTER UNSTABLE FRACTURES OF THE ANKLE: WHAT'S NEW? A SYSTEMATIC REVIEW

BACKGROUND

Unstable ankle fractures are very frequent. Given the instability, they often require surgical treatment, but literature scarcely reports on the outcomes of their management.

QUESTIONS/PURPOSES

For this systematic review we asked: (1) What are the outcomes in treatment of unstable ankle fractures? (2) What about complications of treatment in unstable fractures? (3) What factors influence the outcomes? (4) What about the role of the posterior malleolus?

METHODS

The electronic databases PubMed, Scopus, and Embase were interrogated using the search terms "bimalleolar" or "trimalleolar" and "fracture". Studies were included if they reported on: (1) bimalleolar or trimalleolar fracture in adults; (2) treatment; (3) outcomes reported by scales; (4) follow-up. The final review included 33 studies. The quality of the studies was evaluated with the Methodological Index for Non-randomized Studies (MINORS) questionnaire.

RESULTS

All the outcomes of the thirty-three selected studies were analyzed.

DISCUSSION

Surgical fixation of unstable ankle fractures should always be performed within the first 48 hours from the trauma, preventing instability and post-traumatic osteoarthritis. Surgeon should consider factor may influence functional outcomes. Posterior malleolar fractures should be fixed regardless the size, considering some individual factors.

Does the Inion OTPSTM absorbable plating system induce higher foreign-body reaction than titanium implants? An experimental randomized comparative study in rabbits

Hardware removal after complete fracture healing is a laborious and traumatic procedure that bears the risks of refracture, infection, and soft tissue damage. Absorbable materials for fracture fixation have the advantage of eliminating the need for removal; however, they may stimulate a considerable inflammatory response. For that reason, we compared in a prospective randomized experimental animal model study the incidence of foreign-body reactions between Inion OTPS^TM absorbable plate implants, consisting of carbon trimethylene, L-polylactic acid, and D, L-polylactic acid, and conventional titanium plates. Seventy rabbits were equally divided into two groups. Titanium (Group A) or absorbable (Group B) plates and screws were implanted in the femoral shaft of the rabbits. Wound reaction and laboratory tests including white blood cell count (WBC), erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP) values were measured and compared at different time points. Radiographs and histological analysis of tissue samples from all animals were also used to identify potential foreign-body reactions. WBC showed normal values in both groups. In Group A, ESR levels were higher at all time points but CRP values were normalized at 3 weeks postoperatively. In Group B, ESR and CRP levels reached a peak at 3 weeks and were above normal values throughout the whole experiment (p < 0.001). Radiologic examination revealed periosteal thickening and surrounding sclerosis in 23 out of 35 animals of Group B (66%). All Group A animals had normal radiographic findings. Histopathology showed a typical non-specific foreign-body reaction in all animals in Group B (100%) but none in Group A. However, only four of them (11.8%) developed non-infected wound complications and showed significantly elevated CRP and ESR values (p = 0.054). Although Inion OTPS^TM Biodegradable Plating System stimulates a foreign-body reaction, only a small but not negligible percentage of almost 12% may lead to wound problems. However, this difference compared to titanium plates was of borderline not statistically significant. Future studies should focus on the development of absorbable implants with improved biocompatibility aiming to further decrease the potential of foreign-body reaction and eliminate the need for additional reoperative procedures.

COMPARATIVE STUDY BETWEEN OSTEOSYNTHESIS IN CONVENTIONAL AND BIOABSORBABLE IMPLANTS IN ANKLE FRACTURES

OBJECTIVE

To compare the functional results of ankle fractures treated with metallic and absorbable plates. Twenty patients were randomized into two groups (metallic and absorbable implant groups) and followed prospectively. In the immediate postoperative period, patients were immobilized with plaster casts for one week, which was replaced by a removable cast for another four weeks. Partial weight-bearing was allowed after three weeks, and full weight-bearing after six weeks. Functional recovery was similar in both groups. At six months, three patients in the metallic group complained of local pain, and had their implants removed. One patient in the absorbable group exhibited early dehiscence of the suture and underwent debridement and suturing with good evolution. The American Orthopaedic Foot and Ankle Society (AOFAS) score was similar between the two groups after six and nine months of follow-up. The absorbable implants showed clinical and functional results that were similar to those of metallic implants. Level of Evidence II, Prospective Comparative Study.

Resorbable osteosynthetic devices in pediatric traumatology: a prospective series of 24 cases

Bioresorbable devices are commonly used in traumatology. The biomechanical stability of these materials has improved in the past decade, and they have proven to be biologically non-hazardous, while their main advantage is that their use avoids reintervention for removal of the device. A prospective monocentric study was conducted: 24 patients presenting with a fracture that was amenable to osteosynthesis by small-diameter screws were included. These comprised ten tibial spine fractures, four osteochondritis dissecans of the distal femur, eight fractures of the medial epicondyle of the distal humerus, and two distal tibial apophyseal fractures. One or more screws were used that were made of a copolymer of poly-L-lactide-poly-D-lactide acid and trimethylene carbonate with a diameter of 2.8 mm. All patients were immobilized with a cast. Clinical and radiographic monitoring was conducted every month. The entire follow-up protocol had a duration of 24 months. One patient with osteochondritis dissecans presented with joint effusion. Joint stiffness at the time of cast removal resolved completely after 4 months, except for with three children (one epicondyle fracture, two tibial spine fractures). No subjective or objective instability could be detected by clinical examination. Radiographic follow-up revealed no secondary displacement, and all of the fractures had healed. No osteolysis was seen around the screws. No growth disturbances were noticed. Bioresorbable materials thus appear to be a suitable alternative approach for certain pediatric fractures. Their use resulted in outcomes similar to traditional techniques in terms of functional properties and bone healing. Although initial costs are presumably slightly higher, by avoiding a removal operation the total financial burden is most likely reduced.

LEVEL OF EVIDENCE

III.

Absorbable biologically based internal fixation

Absorbable devices for use in internal fixation have advanced over the years to become reliable and cost-effective alternatives to metallic hardware. In the past, biodegradable fixation involved a laborious implantation process, and induced osteolysis and inflammatory reactions. Modern iterations exhibit increased strength, smoother resorption, and lower rates of reactivity. A newer generation manufactured from silk has emerged that may address existing limitations and provide a greater range of fixation applications.

Functional outcome of ankle fracture patients treated with biodegradable implants

BACKGROUND

Biodegradable devices have been developed to overcome the disadvantages of metallic implants especially the need for their subsequent removal, though they have their own drawbacks like poor mechanical properties and tissue reactions. Aim of this prospective study was to access the outcome of bimalleolar fractures fixed with biodegradable plates and screws.

METHODS

A prospective study was conducted between July 2006 and November 2008 comprising of sixteen patients with unilateral bimalleolar fractures. Fibula fractures were fixed with biodegradable plates and medial malleoli with screws. Patients were followed at two weeks, six weeks, three months, six months, twelve months and eighteen months. Final evaluation was done using Olerud Molander ankle score.

RESULTS

Six patients had excellent results; four patients had good results and six patients had fair performance. No patient in this series had a poor outcome. One patient had both pain and swelling at 14 weeks postoperatively which settled down with debridement and antibiotics. None of the patients needed implant removal.

CONCLUSION

Biodegradable plates and screws when used to fix bimalleolar fracture along with restricted weight bearing, provide satisfactory fracture healing, good functional results and reduce the need of implant removal.

Lateral fixation of AO type-B2 ankle fractures: the Acutrak plus compression screw technique

The Acutrak plus compression screw (APCS) (Acumed Inc., Beaverton, OR, USA) is an intramedullary implant which can achieve stable fixation with minimum soft tissue dissection. The characteristics of the APCS include fully-threaded length, headless, cannulated, and variable thread pitch. Twenty-three patients with AO type-B2 ankle fractures treated with lateral fixation by an APCS were retrospectively reviewed. Evaluation of postoperative roentgenograms for adequacy of reduction revealed a good reduction in 22 of 23 (95.7%) patients. The average wound incision was 4.1 cm. The operative time was 25.3 minutes. All the ankle fractures showed radiographic evidence of healing within four months. At the final follow-up, the ankle scores of the patients were evaluated for functional outcomes. Good to excellent results were obtained in 21 (91.3%) patients. No patient complained of symptomatic hardware. In conclusion, lateral fixation of AO type-B2 ankle fractures by APCS offers several advantages including stable fixation, a small surgical wound, less dissection of soft tissue, no palpable hardware, and easy application with a short operating time.

The use of a biodegradable mesh plate to augment grafting of an acetabular defect: Laboratory investigation and clinical pilot study

We used a biodegradable mesh to convert an acetabular defect into a contained defect in six patients at total hip replacement. Their mean age was 61 years (46 to 69). The mean follow-up was 32 months (19 to 50). Before clinical use, the strength retention and hydrolytic in vitro degradation properties of the implants were studied in the laboratory over a two-year period. A successful clinical outcome was determined by the radiological findings and the Harris hip score. All the patients had a satisfactory outcome and no mechanical failures or other complications were observed. No protrusion of any of the impacted grafts was observed beyond the mesh. According to our preliminary laboratory and clinical results the biodegradable mesh is suitable for augmenting uncontained acetabular defects in which the primary stability of the implanted acetabular component is provided by the host bone. In the case of defects of the acetabular floor this new application provides a safe method of preventing graft material from protruding excessively into the pelvis and the mesh seems to tolerate bone-impaction grafting in selected patients with primary and revision total hip replacement.