Retrieval of a Lane Plate 82 Years After Implantation: Case Report, Metallurgical Analysis, and Historical Review.

Background: The Lane plate was one of the first widely used bone plates, utilized in the first decades of the twentieth century. Here we present the results of a retrieval analysis on a Lane plate, and a review of the history of these plates. Our patient underwent plating of her femur with a Lane plate in 1938. She developed a sciatic nerve palsy, managed surgically later that year by Dr. Arthur Steindler at the University of Iowa. Her femur healed, her nerve recovered, and she did well until 2020, at age 94, when she presented to the University of Iowa with a draining sinus that appeared to communicate with the plate. She underwent irrigation and debridement with hardware removal. The plate was sectioned, and its composition and structure characterized. Methods: We retrieved hard copies of the patient's archived medical records from 1938, which document in detail the treatments performed by Dr. Steindler. The plate was analyzed using scanning electron microscopy (SEM) to characterize the surface of the plate. A cross section was taken from the plate, and the composition of the alloy was determined using energy dispersive x-ray spectroscopy (EDS). A review of the literature surrounding early plating techniques was conducted. Results: Our patient recovered from her surgery and soon returned to her baseline state of health. Intraoperative cultures grew C. acnes. Analysis of the surface of the plate demonstrated significant corrosion, and the crystal structure seen on SEM suggested a strong alloy that is prone to corrosion. Analysis of the cross section with EDS demonstrated an alloy containing 94.9% iron, 1.7% aluminum, 1.2% chromium, and 1.1% manganese. Conclusion: The Lane plate was introduced around 1907 by Sir William Arbuthnot Lane, a British surgeon, and was one of the first widely used devices for the plating of fractures. Given that this patient was likely one of the last to be treated with a Lane plate, this may be the final opportunity for such a retrieval analysis. Level of Evidence: IV.

Is Heterotopic Ossification Removal From Alloplastic Temporomandibular Joint Prosthesis Using Er,Cr:YSGG Laser Superior to Conventional Methods?

PURPOSE: Heterotopic ossification (HO) formed over the major components and fixation screw heads of an alloplastic temporomandibular joint replacement (TMJR) prosthesis can result in decreased quality of life, limited function, prosthesis failure, and hinder prosthesis revision, replacement, or removal. This study simulated HO removal from the major components and fixation screw heads of alloplastic TMJR prostheses using an erbium, chromium-doped yttrium, scandium, gallium, and garnet (Er,Cr:YSGG) laser and compared the results to conventional methods of HO removal. The surface morphology and chemical structure of the exposed components were analyzed. The investigators hypothesize that HO removal with an Er,Cr:YSGG laser causes less damage to TMJR prosthesis components compared to conventional HO removal methods. METHODS: This multiple test descriptive analysis simulated HO removal from TMJR prostheses mounted to stereolithic models. Simulated HO removal was completed using a novel Er,Cr:YSGG laser method and conventional methods which utilized a fissure carbide bur in a high-speed rotary instrument, a standard osteotome, and an ultrasonic aspirator. Surfaces exposed on the TMJR prostheses were analyzed for morphological or chemical change using scanning electron microscopy, energy dispersive X-ray spectroscopy, and Raman spectroscopy. RESULTS: The Er,Cr:YSGG laser did not adversely affect the titanium screws or titanium components of the TMJR prostheses, while conventional methods of HO removal did. HO removal using the Er,Cr:YSGG laser and conventional methods both inflicted surface damage to the fossa ultrahigh molecular weight polyethylene component of the TMJR prostheses. CONCLUSION: Damage inflicted to titanium alloy or commercially pure titanium components of TMJR prostheses by conventional HO removal methods can be avoided by instead removing HO with an Er,Cr:YSGG laser. However, long exposure of the Er,Cr:YSGG laser to ultrahigh molecular weight polyethylene surfaces should be avoided. Additional research to expand on applications to other procedures and in other surgical fields is encouraged.

Alloys Used in Different Temporomandibular Joint Reconstruction Replacement Prostheses Exhibit Variable Microstructures and Electrochemical Properties.

PURPOSE: Metallic temporomandibular joint replacement (TMJR) systems vary depending on design, material composition, and manufacturing methods such as casting, forging, and additive manufacturing. Therefore, the purpose of this study was to measure the association between manufacturing process of TMJR systems in terms of microstructure and electrochemical properties. MATERIALS AND METHODS: The sample was composed of new or surgically retrieved TMJ replacement devices of either titanium alloy (Ti6Al4V) or cobalt-chromium-molybdenum (CoCrMo) alloy from 8 different manufacturers. The primary predictor variable was alloy type, according to its manufacturing process (wrought, cast, additively manufactured [AM]). The primary outcome variables were 1) microstructure (grain size, aspect ratio, and phase content) and 2) corrosion potential and current, polarization resistance, and capacitance. Differences between alloy groups were determined by t tests, Kruskal-Wallis, and Mann-Whitney tests. RESULTS: We demonstrated that the TMJR CoCrMo and Ti6Al4V alloy microstructures can vary broadly within American Society for Testing and Materials specifications, where the components made of Ti6Al4V had 3 types of microstructures (equiaxial, bimodal, and martensitic) out of 10 samples, and the components made of CoCrMo had 2 types of microstructure (equiaxial and dendritic) out of 16 samples. Some CoCrMo alloys exhibited preferential corrosion sites, while wrought Ti6Al4V alloys trended toward a superior corrosion behavior (corrosion rate: 2 × 10-9 A/cm2, polarization resistance: 5,000,000 kΩcm2, and capacitance: 10 µSsa/cm2) compared with AM alloys (39 × 10-9 A/cm2, 1676 kΩcm2, 36 µSsa/cm2, respectively), where 4 samples of each group were tested and repeated 5 times. Among four AM devices, two exhibited a significantly inferior corrosion behavior. CONCLUSIONS: Although AM is an exciting emerging new technology that allows manufacturing of custom-made TMJR, their corrosion behavior is still inferior in comparison to that of traditional wrought alloys. Preventing corrosion is crucial because it can cause surface defects that may lead to implant fracture.