Locking Compression Plate as an External Fixator for the Treatment of Tibia Infected Bone Defects

Purpose This study was designed to observe the medium-term efficacy of an induced membrane technique combined with a locking compression plate as an external fixator for the treatment of tibia infected bone defects. Methods Patients with a tibial infection were admitted to our department between January 2013 and November 2014. All patients were treated with the induced membrane technique. In the first stage, polymethyl methacrylate (PMMA) cement was implanted in the defects after debridement and then fixed with a locking compression plate (LCP) as an external fixator. In the second stage, bone grafts were implanted to rebuild the defects. The external plates were replaced with nails in 57 patients (internal group), and the remaining 30 patients were not exchanged with fixation (external group). The infection control rate, bone union rate, and complications of the two groups were compared. Results Eighty-seven patients were enrolled in this study, and all patients had a minimum follow-up of 5 years (average 62.8 months) after grafting. Eighty-three patients (95.4%) achieved bone union, and the average union time was 6.77 months. Five patients (5.7%) experienced recurrence of infection. Complications included pin tract infection, fixation loosening, deformity connection, and limitation of joint range of motion (ROM). No significant differences in the infection control rate or bone defect union rate were noted between the two groups. The overall rate of complications in the external group was 50%, which was greater than that noted in the internal group (21.1%). Conclusions Locking compression plates are external fixators with smaller sizes that are easier to operate than conventional annular fixators or assembled external fixators. The use of locking compression plates in combination with the induced membrane technique in the treatment of tibia infected bone defects can achieve good clinical efficacy after medium-term follow-up.

Functional Outcome and Inflammatory Response of Patients with Extra-Articular Distal Humeral Fractures following Implantation of Anatomically Precontoured Locking Compression Plates through a Posterior Approach

Distal humeral fractures are challenging injuries to surgically correct and account for up to 2% of all adult fractures. Surgical management of extra-articular distal humeral fractures is challenging considering surgical approach, implant selection, and position of the implant owing to the availability of different precontoured implants and plate configurations. Anatomically precontoured locking compression plates (APLCPs) allow the placement of angular stable screws right underneath the reduced joint surface fragments. To date, there is a lack of evidence supporting its superiority to conventional locking plate osteosynthesis (LPO) in treating extra-articular distal humeral fractures. The objective of the study is to evaluate the efficacy and safety of APLCPs in the treatment of extra-articular distal humeral fractures. A total of 100 patients diagnosed with humeral fractures and receiving treatments in our hospital between May 2018 and May 2020 fulfilled inclusion and exclusion criteria and were randomly assigned to LPO and APLCP groups according to the odd-even of the order of hospital admission, 50 cases per groups. Clinical endpoints were assessed including operation time; in-bed time; length of hospital stay; volume of intraoperative blood loss; VSA scores before and 24, 48, and 72 h after surgery; MEPS scores before and 3, 6, and 12 months after surgery; range of motion, flexion, and extension of the elbow; serum levels of CK, CRP, and IL-6; and incidence of complications after surgery. It was found that the APLCP group exhibited shortened operation time and in-bed time, decreased length of hospital stay, and reduced volume of intraoperative blood loss compared to the LPO group (all P < 0.001 ). The two groups had declined VSA scores concomitant with increased MEPS scores after surgery in a time-dependent manner ( P < 0.001 ). Notably, the VSA scores in the APLCP group were all lower than those in the LPO group at indicated time points (24, 48, and 72 h) after surgery ( P < 0.001 ). Besides, the MEPS scores in the APLCP group were all higher than those in the LPO group at indicated time points (3, 6, and 12 months) after surgery ( P < 0.001 ). It was revealed that the patients receiving extra-articular distal humeral APLCP through posterior approaches exhibited greater ranges of motion, flexion, and extension of the elbow than those receiving LPO after surgery ( P < 0.001 ). The patients receiving extra-articular distal humeral APLCP through posterior approaches exhibited lower serum levels of IL-6, CRP, and CK than those receiving LPO after surgery (IL-6: P = 0.007 , CRP: P = 0.001 , CK: P = 0.001 ). The APLCP had a lower total incidence rate of complication than the LPO group (48.00% vs. 18.00%, P = 0.003 ). In conclusion, these data support the notion that the implantation of anatomically precontoured APLCP through a posterior approach allows for improved functional outcomes and attenuated inflammatory response and prevents the incidence of postoperative complications compared to conventional LPO for internal fixation of extra-articular distal humeral fractures.

3D Topology Optimization and Mesh Dependency for Redesigning Locking Compression Plates Aiming to Reduce Stress Shielding

Current fixation plates for bone fracture treatments are built with biocompatible metallic materials such as stainless steel, titanium, and its alloys (e.g., Ti6Al4V). The stiffness mismatch between the metallic material of the plate and the host bone leads to stress shielding phenomena, bone loss, and healing deficiency. This paper explores the use of three dimensional topology-optimization, based on compliance (i.e., strain energy) minimization, reshaping the design domain of three locking compression plates (four-screw holes, six-screw holes, and eight-screw holes), considering different volume reductions (25, 45, and 75%) and loading conditions (bending, compression, torsion, and combined loads). A finite-element study was also conducted to measure the stiffness of each optimized plate. Thirty-six designs were obtained. Results showed that for a critical value of volume reductions, which depend on the load condition and number of screws, it is possible to obtain designs with lower stiffness, thereby reducing the risk of stress shielding.