ANATOMICAL AND MORPHOLOGICAL STUDY ON RADIAL HEAD AND ITS CLINICAL IMPLICATION

Introduction: The lateral forearm bone, Radius is a fundamental element for the physiological or prosthetic stability of the elbow and superior radio-ulnar joints. It also participates in elbow exion, supination & pronation. The knowledge of shape and size of the radius will be useful for the radial head prosthesis. The morphometric data may help orthopedic surgeons for reconstructive surgery. Aims & Objectives: To determine the morphometric parameters of proximal end of radius and to assess its clinical signicance. Methodology: A cross sectional morphometric study was conducted on sixty-six undamaged adult dry human Radii of unknown age and sex, in the Department of Anatomy, MJNMCH, by using a digital vernier caliper of accuracy of 0.01mm. Anteroposterior diameter, transverse diameter, medial height and lateral height and depth of superior articular facet were measured. Result: In the present study mean values (±standard deviation) of anteroposterior diameter, transverse diameter, medial height, lateral height of radial head and depth of superior articular surface were 16.86±2.92mm, 16.22±2.91mm, 8±1.7mm, 5.8±1.29mm and 1.1±0.3mm for the right side and 18.71±2.05mm, 18.14±2.1mm, 8.5±1.33mm, 6.15±0.9mm and 1.21±0.3mm for the left side respectively. The average values of anteroposterior and transverse diameter of radial head show signicant difference between right side and left side of radius. Conclusion: The knowledge of size and shape of radial head is necessary for creation of radial head prosthesis that should be automatically and biochemically correct so that the open be safely applied. The study was conducted to nd out some additional and relevant information on the morphometric parameters of radial head so that it can help in creation of radial head prosthesis.

Precision of computed tomography and cartilage-reproducing image reconstruction method in generating digital model for potential use in 3D printing of patient-specific radial head prosthesis: a human cadaver study

Background A prosthetic replacement is a standard treatment for an irreparable radial head fracture; however, the surface mismatch of the commercially available designs is concerned for the long-term cartilage wear. The patient-specific implant created from 3D printing technology could be favorable in replicating the normal anatomy and possibly reduce such sequela. Our study aimed to assess the precision of the computed tomography (CT) and cartilage-reproducing image reconstruction method (CIRM) in generating digital models for potentially use in manufacturing the patient-specific prosthesis from 3D printing. Methods Eight intact elbows (3 right and 5 left) from 7 formalin-embalmed cadavers (4 males and 3 females) with mean age of 83 years (range, 79–94 years) were used for this study. Computerized 3D models were generated from CT, and CIRM. The cartilage-reproducing image reconstruction method has compensated the cartilage profile based on the distance between the subchondral surfaces of the radial head and surrounding bones in CT images. The models of actual radial head geometry used as the gold standard was generated from CT arthrography (CTA). All models of each specimen were matched by registering the surface area of radial neck along with the tuberosity. The difference of head diameter, head thickness, and articular disc depth among three models was evaluated and analyzed by Friedman ANOVA and multiple comparison test using Bonferroni method for statistical correction. A p-value of less than 0.01 was considered statistically significant. The difference of overall 3D geometry was measured with the root mean square of adjacent point pairs. Results The analysis displayed the difference of diameter, thickness, and disc depth across the models (p< 0.01). Pairwise comparisons revealed statistically significant difference of all parameters between CTA models and CT models (p< 0.01) whereas no difference was found between CTA models and CIRM models. The mean difference of overall 3D geometry between CTA models and CT models was 0.51±0.24 mm, and between CTA models and CIRM models was 0.24±0.10 mm. Conclusions CIRM demonstrated encouraging results in reestablish the normal anatomy and could be potentially used in production process of 3D printed patient-specific radial head prosthesis.

Acute Joint Blockage due to Abrasion-Related Dislocation of a Silastic Radial Head Prosthesis: A Histological Examination after 14 Years of Durability

The implantation of a radial head prosthesis can take place as a therapeutic option after radial head fracture. There are various implants for this purpose. Many studies and case reports about silastic radial head prosthesis implantation describe foreign body reactions with accompanying synovitis and poor functional results. A few studies have investigated the reason for the material failure and the accompanying synovitis. The case report presented shows an unusually long durability of an in situ 14-year silastic radial head prosthesis. 14 years after implantation, a previously full-time working and healthy patient presented himself with a dislocation of the silastic radial head prosthesis and atraumatic joint blockage of the right elbow triggered by a negligible movement. The prosthesis was removed surgically. We found a macroscopic foreign body reaction intraoperatively. In a histopathological examination, with hematoxylin and eosin staining (HE) in 40x and 100x magnification, we have seen an aseptic inflammatory response to foreign bodies with activated epithelial cells and multinucleated giant cells with intracytoplasmic foreign material. Due to these problems, the silastic radial head prosthesis is no longer used today. However, there are still patients with the implanted silastic radial head prosthesis, which should therefore be checked regularly. A metal prosthesis also does not seem to be an optimal alternative due to cartilage wear and loss of ROM. The choice of prosthesis material should be selected carefully and patient-specific in radial head prosthetics according of the results presented.

Evaluation of two different types of radial head prosthesis in practical use. Using either Evolve® or MoPyC® radial head prosthesis in the treatment of comminuted radial head fractures

The aim of this retrospective study was to undertake a comparative evaluation of the Evolve® modular metallic radial head implant prosthesis and the MoPyC® pyrocarbon prosthesis in acute care. Seventyfive patients having a comminuted radial head fracture with an Evolve® prosthesis (=G1) and 11 with a MoPyC® prosthesis (=G2) were available for a follow-up. Postoperative patient outcomes were evaluated according to a standardized follow-up protocol which included the Morrey rating system. Assessment criteria were range of motion (ROM), functional scores, and rate of complications. G1 showed a mean Morrey score of 86 points. Four direct prosthesis complications were observed in this group (n=75). The average achieved Morrey score in G2 was 84 points. In this group (n=11), 2 direct prosthesis complications were diagnosed. The average range of motion did not differ greatly between both groups. Radial head replacement with either prosthesis yielded sufficient to satisfactory results in a mid-term perspective regarding the range of motion and function of the elbow joint when performed in carefully selected patients. The Evolve® Prothesis appears to show a slightly lower rate of complication by way of a similar functional outcome.