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Additive manufacturing (AM) of titanium (Ti) alloys has always fascinated researchers owing to its high strength to weight ratio, biocompatibility, and anticorrosive properties, making Ti alloy an ideal candidate for medical applications. The aim of this paper is to optimize the AM parameters, such as Laser Power (LP), Laser Scan Speed (LSS), and Hatch Space (HS), using Analysis of Variance (ANOVA) and Grey Relational analysis (GRA) for mechanical and surface characteristics like hardness, surface roughness, and contact angle, of Ti6Al4V ELI considering medical implant applications. The input parameters are optimized to have optimum hardness, surface roughness and hydrophilicity required for medical implants.

Background: Wrist arthroplasties have not achieved clinical outcomes comparable to those of shoulders and knees, being offered low-demand patients due to a high failure rate. In the 90s, there were no wrist arthroplasties available for high-demand patients. An experimental setup for the development of a new wrist arthroplasty intended for all wrist patients were done. A long-term final follow-up to evaluate the performance of the experimental arthroplasty was performed.

Methods: A novel uncemented modular wrist prosthesis with conical threaded fixation, metal-on-metal coupling and ball-and-socket articulation was developed. In an experimental study, eight patients (7 men, 53 years of age) were operated between 2001 and 2003, to treat non-inflammatory primary or secondary osteoarthritis. Published mid-term results (7–9 years) demonstrated satisfactory function, but two arthroplasties were converted to arthrodesis due to infection.

Results: At final follow-up 15–20 years after primary surgery, the remaining six patients still had a wrist arthroplasty (in three the original) in situ. The clinical results were good. Low pain (median = 0), Quick Disability of Arm, Shoulder and Hand (QDASH median 11) and Patient Rated Wrist and Hand Evaluation (PRWHE median = 14) scores were reported. Wrist active range of motion (AROM) was 64% and grip strength 86% compared to the opposite side. None regretted choosing arthroplasty knowing the outcome.

Conclusions: Despite technical errors and the implementation of an incomplete prototype, this new concept for arthroplasty has demonstrated promising long-term fixation, a stable articulation with good range of motion, satisfactory function and pain reduction in high-demand patients.

Level of Evidence: Level IV (Therapeutic)

Objective: In the present study, we investigate the biological performance of a calcium phosphate ceramics (CPC) bone substitute combined with poly-hydroxybutyrate-co-hydroxyvalerate (PHBV). Materials and Methods: A particulate CPC [45% beta-tricalcium phosphate ($\beta$-TCP) and 55% of dihydrated dicalcium phosphate (DCPD)] was incorporated into a biodegradable copolymer PHBV. Two series of the composite, 1 and 2, with CPC–PHBV weight ratios of (40%–60% and 60%–40%), respectively, were prepared using chloroform for dissolving the polymer and a pressure molding process for shaping the composite samples. After particle size analysis, the two composites were characterized by scanning electron microscopy (SEM) and energy dispersive spectrometry (EDS). In a second step, a 10mm bony segmental defect created in the tibias of 20 New Zealand White Rabbits was filled randomly with either composite 1 for group 1 or composite 2 for group 2. There were 10 animals in each group. Clinical, radiological and histological assessments were then carried out to evaluate the biological properties of developed CPC–PHBV composites. Results: For both variants of the developed CPC–PHBV biocomposite, there was evidence of osseous consolidation within three months. An in vivo investigation revealed the biological properties of the biocomposite, namely, biocompatibility, bioactivity, biodegradability and osteoconductivity. The morphological characteristics, granule size and chemical composition, were indeed found to be favorable for osseous cell development. This study likewise showed lower mortality for the variant with weight ratio (40%CPC–60%PHBV). Conclusion: An in vivo investigation revealed that the new biomaterial composed of CPC and PHBV exhibits manifest osteoconductivity and bioactivity with better degradation kinetics than the CPC. Moreover, the variant with 40%CPC/60%PHBV appeared more resistant to infection than the 60%CPC/40%PHBV which is an indicator of biocompatibility.

Nondestructive three-dimensional (3D) micro-computed tomography (CT) image analysis used in orthopedic research needs to be accompanied by adequate tools for the numerical assessment of experimental systems. Such quantitative tools should be user-friendly and intuitive, not too complex for the orthopedic researcher to implement, as well as accurate and repeatable in order to be suitable for laboratory application. Here, two experimental systems are examined and straightforward micro-CT analysis methods are described, allowing the experimental outcomes to be accurately quantified in a flexible and multidimensional manner. These systems include the study of osteointegration around a metal implant in bone, and the study of porosity of a biocompatible scaffold matrix for tissue engineering (specifically, the study of scaffolds for permeability to cellular ingrowth) Both studies involve a number of standard image analysis techniques applied in a 3D manner, such as erosion and dilation (applied flexibly to both the image and the region of interest), distance transforms, and novel techniques like “shrink wrap”. Applied in combination in an easily programmable “task list” (otherwise known as “scripting”), these functions provide a powerful and versatile range of 3D structural analyses.

The possibilities of movement and electrochemical reduction of fibroin macroions in the presence of tricalcium phosphate ions in the form of a nanocoating during electrolysis have been studied. The manifestation of a non-Newtonian flow of a mixture of macroions and ions in a shear flow, the conditions for their electrochemical reduction in the form of a nanocoating with uniform morphology, and thickness on the electrode surface are revealed. It was found that the excess ions in the mixture and the uneven relief of the electrode surface contribute to the formation of a nanocoating with an inhomogeneous and uneven thickness.

Background: This study evaluated the feasibility of using a low-profile titanium (Ti) plate implant, also known as the Ti-button, for Zone II flexor tendon repair. We hypothesize that the use of the Ti-button can distribute the tensile force on the digital flexor tendons to achieve better biomechanical performance.

Methods: Twenty lacerated porcine flexor tendons were randomly divided into two groups and repaired using Ti-button or 6-strand modified Lim-Tsai technique. Ultimate tensile strength, load to 2 mm gap force, and mode of failure were recorded during a single cycle loading test. We also harvested twelve fingers with lacerated flexor digitorum profundus tendons from six fresh-frozen cadaver hands and repaired the tendons using either Ti-button method or modified Lim-Tsai technique. A custom-made bio-friction measurement jig was used to measure the gliding resistance and coefficient of friction of the tendon sheath interface at the A2 pulley.

Results: The ultimate tensile strength, load to 2 mm gap force, stiffness, and gliding resistance of the Ti-button repairs were 101.5 N, 25.7 N, 7.8 N/mm, and 2.2 N respectively. Ti-button repairs had significantly higher ultimate tensile strength and stiffness than the modified Lim-Tsai repair. However, Ti-button also increased the gliding resistance and coefficient of friction but there was no significant difference between the two repair techniques.

Conclusions: Ti-button repair displayed comparable mechanical properties to the traditional repair in terms of 2-mm gap formation and gliding resistance, but with a stronger repair construct. Thus, this deepened our interest to further investigate the potential of using Ti-button implant in Zone II flexor tendon repair by studying both the mechanical and biochemical (tendon healing) properties in more in-depth.

Background: Proximal interphalangeal joint (PIPJ) arthroplasty using a Swanson implant is commonly used for the treatment of PIPJ arthritis despite newer implants being available. Many patients develop arthritis in more than one digit and some tend to have multiple digits operated on in their lifetime. There is paucity of literature on the outcomes of multiple PIPJ arthroplasty in one sitting. The aim of this study is to determine the outcomes of PIPJ arthroplasty using a Swanson implant done for multiple digits at one sitting.

Methods: We retrospectively reviewed the outcomes of multiple Swanson PIPJ arthroplasty during a single operation from 2008 to 2018 in 13 patients (43 arthroplasties). We compared pre- and post-operative results of flexion/extension arcs, grip and pinch strength and questionnaires subsequently compared QuickDASH (Disabilities of Arm, Shoulder and Hand), Patient Evaluation Measure (PEM) and Visual Analogue Score (VAS) scores. Data were analysed with a Mann–Whitney U test.

Results: Patients on average attended 5.6 hand therapy sessions over 5.1 months post-operatively. Average flexion/extension arc improved from 31.9° pre-operatively to 37.2° post-operatively. Average grip strength increased from 7.2 kg to 10.2 kg. The QuickDASH, PEM and VAS scores improved in keeping with the reported literature. There were no implant failures.

Conclusion: We demonstrate similar outcomes for multi-digit Swanson PIPJ arthroplasty compared to the literature for single digit Swanson PIPJ arthroplasty. We conclude that multi-digit arthroplasty in a single operation is safe and effective.

Level of Evidence: Level IV (Therapeutic)