Metal implant allergy

Noble Metals for Modern Implant Materials: MOCVD of Film Structures and Cytotoxical, Antibacterial, and Histological Studies

This work is aimed at developing the modification of the surface of medical implants with film materials based on noble metals in order to improve their biological characteristics. Gas-phase transportation methods were proposed to obtain such materials. To determine the effect of the material of the bottom layer of heterometallic structures, Ir, Pt, and PtIr coatings with a thickness of 1.4-1.5 μm were deposited by metal-organic chemical vapor deposition (MOCVD) on Ti₆Al₄V alloy discs. Two types of antibacterial components, namely, gold nanoparticles (AuNPs) and discontinuous Ag coatings, were deposited on the surface of these coatings. AuNPs (11-14 nm) were deposited by a pulsed MOCVD method, while Ag films (35-40 nm in thickness) were obtained by physical vapor deposition (PVD). The cytotoxic (24 h and 48 h, toward peripheral blood mononuclear cells (PBMCs)) and antibacterial (24 h) properties of monophase (Ag, Ir, Pt, and PtIr) and heterophase (Ag/Pt, Ag/Ir, Ag/PtIr, Au/Pt, Au/Ir, and Au/PtIr) film materials deposited on Ti-alloy samples were studied in vitro and compared with those of uncoated Ti-alloy samples. Studies of the cytokine production by PBMCs in response to incubation of the samples for 24 and 48 h and histological studies at 1 and 3 months after subcutaneous implantation in rats were also performed. Despite the comparable thickness of the fibrous capsule after 3 months, a faster completion of the active phase of encapsulation was observed for the coated implants compared to the Ti alloy analogs. For the Ag-containing samples, growth inhibition of S. epidermidis, S. aureus, Str. pyogenes, P. aeruginosa, and Ent. faecium was observed.

Metal Hypersensitivity in Joint Arthroplasty

Metal hypersensitivity in joint arthroplasty is a very controversial topic with limited evidence. With increasing numbers of joint replacements being done annually, a clear understanding of the pathogenesis, clinical picture, preimplant screening, postimplant workup, and treatment plan is crucial. This review article looked at all the available evidence regarding metal hypersensitivity and summarized the key findings. An algorithm was also proposed for preimplant screening, postimplant workup, and management.

Comparison of low-profile locking plate fixation versus antegrade intramedullary nailing for unstable metacarpal shaft fractures--A prospective comparative study

BACKGROUND

The purpose of this study was to compare the effectiveness of mini-open antegrade intramedullary nailing (AIN) and open reduction and internal fixation (ORIF) using the low-profile locking plate for angulated metacarpal shaft fractures, through prospective comparative trial.

METHODS

Group 1 (mini-open AIN; 40 patients) and the other consecutive patients in group 2 (locking plate; 35 patients) who met our inclusion/exclusion criteria were investigated between January 2010 and December 2016. We compared radiological findings (e.g., union and residual angulation or shortening); clinical conditions (e.g., pain, measured on a visual analog scale (VAS), and Disabilities of the Arm, Shoulder, and Hand (DASH) scores); active range of motion (ROM); and grip strength.

RESULTS

Union was achieved in both groups without any major complications. The final angulation measurements were not significantly different (p = 0.402). The final VAS scores were not different (p = 0.868); however, the final DASH score was better in group 1 than in group 2 (p = 0.034). The plates were removed in 14 patients at 9.6 months postoperatively for various reasons. Mean ROM at the time of hardware removal in these 14 patients was significantly lower compared with the final ROM in groups 1 and 2 (non-removal patients). Final grip strengths recovered significantly more in group 1 than in group 2 (p = 0.029). Extension lag was found in four patients in group 2, and the mean amount was 15°; however, it was resolved by tenolysis during hardware removal.

CONCLUSIONS

Both mini-open AIN and low-profile plate fixation are excellent options for metacarpal shaft fractures without significant radiological or clinical problems; however, some clinical outcomes evaluated at least 2 years postoperatively, such as DASH scores and grip strength, were better in the AIN group than in the locking plate group. Plate removal was performed under anesthesia in some patients in the plate group for various reasons, and this may have caused the small differences in the final outcomes evaluated 2 years after surgery.

Comparison of Dorsal Plate Fixation Versus Intramedullary Headless Screw Fixation of Unstable Metacarpal Shaft Fractures: A Biomechanical Study

Background: Recently, intramedullary headless screw (IMHS) has shown promise as an alternative to dorsal plate fixation of metacarpal fractures. The purpose of this study was to assess the biomechanical performance of IMHS versus plating. We hypothesized that IMHS fixation provides inferior stability to plating. Methods: Metacarpal fracture model with 3-mm of volar gapping in forty-four human cadaveric metacarpals was created. The specimens were divided into 5 groups: Group 1, 1.5-mm non-locking plate; Group 2, 1.5-mm locking plate; Group 3, 2.0-mm non-locking plate; Group 4, 2.0-mm locking plate; and Group 5, 2.4-mm short cannulated IMHS. A 4-point bending model was used to assess load-to failure (LTF) and stiffness. Results: Mean LTF was 364 ± 130 N for 1.5-mm non-locking plates, 218 ± 94 N for 1.5-mm locking plates, 421 ± 86 N for 2.0-mm non-locking plates, 351 ± 71 N for 2.0-mm locking plates, and 75 ± 20 N for IMHS. Mean stiffness was 91 ± 12 N/mm for 1.5-mm non-locking plates, 110 ± 77 N/mm for 1.5-mm locking plates, 94 ± 20 N/mm for 2.0-mm non-locking plates, 135 ± 16 N/mm for 2.0-mm locking plates, and 55 ± 15 N/mm for IMHS. IMHS demonstrated significantly lower LTF and stiffness than plates. Conclusions: IMHS fixation of unstable metacarpal shaft fractures offers less stability compared to plating when loaded in bending. The LTF and stiffness of IMHS versus plating of metacarpal shaft fractures has not been previously quantified. Our results reveal that IMHS fixation is less favorable biomechanically and should be carefully chosen in regards to fracture stability.

Metal allergy after first metatarsophalangeal total joint replacement--Case report

A 62-year-old female patient presented with a symptomatic metal allergy six weeks after first metatarsophalangeal total joint replacement using ROTOGLIDE implant. Preoperatively, there was no history of hypersensitivity. The symptomatic dermatitis was evaluated using dermal patch testing. The implant had to be removed. The possible agents for the allergic reaction are discussed.

A Delayed Allergic Reaction to Polypropylene Suture Used in Flexor Tendon Repair: Case Report

We report a patient who developed a delayed hypersensitivity reaction to a polypropylene suture used in flexor pollicis longus repair. We also review the literature and aim to increase the awareness of hand surgeons to the presentation, diagnosis, and management of these rare cases.