Modular Radial Head Prosthesis Research Articles

Downsizing effect of a modular radial head prosthesis on the lateral collateral ligament of the elbow: A cadaveric study

BackgroundIt remains unclear how the head and stem diameters for the radial head prosthesis could affect mechanical properties of the lateral collateral ligament measured by strain changes during elbow and forearm motions. MethodsEight cadaveric specimens were secured to the device, which allows elbow flexion-extension and forearm pro-supination. Using six different implant combinations comprising 2 sizes for the head (long- and short-axis of the native head) and 3 sizes for the stem (press-fit, −1 mm, and −2 mm downsizing), prostheses were attached via the posterior approach. A differential variable reluctance transducer placed on the central portion of the radial collateral ligament were used for strain measurement with elbow flexion at 0°, 30°, 60°, and 90°. At each position, the strain patterns with the forearm in the neutral and 45° pro-supination positions were also assessed. FindingsSpecimens implanted with long-axis head component showed greater increases in the ligament strain during elbow flexion than intact specimens or those implanted with short-axis head. Compared to press-fit stem, implants with downsizing to −1 mm approximated strain patterns during pro-supination with elbow extension to intact condition. InterpretationMorphologic variation of the head and stem components in radial head prostheses led to altered strain patterns in the lateral collateral ligament during elbow and forearm motions. A short-axis head component can be used to prevent excessive strain changes after the prosthesis application. Downsizing of the stem component might be an option for approximating the biomechanics at the radiocapitellar joint during forearm rotation to the intact elbow.

Study of role of prosthetic replacement for comminuted fracture of head of radius

Objective: We had evaluated our experience in the treatment of Morrey Modified Masons type III and IV radial head fractures with radial head prosthesis. Materials and Methods: From April 2014 to September 2017, modular radial head prostheses were performed in thirty patients. There were twenty female and ten male with mean age of forty years. The follow-up was a mean of 25 months. Fractures of the radial head have been classified by Morrey Modified Masons classification. The indications for a radial head replacement were type III fractures in 24 cases, type IV fractures in 6 cases, and comminuted radial fracture associated with disruption of the medial collateral ligament in 3 cases. Patients were assessed postoperatively and on follow-up based on Mayo Elbow Performance Index (MEPI) Score. Results: By using the MEPI, out of thirty cases, twenty cases had excellent results, seven cases had good results, two cases had fair results, and one case had poor result. Twenty-eight cases had no complications, one case had infection, and one case had implant failure. Conclusion: Modular radial head prosthesis can be used successfully for treatment of the Morrey Modified Masons type III and IV radial head fractures.

Advantages of Modular Radial Head Prosthesis Use in Highly Comminuted Fractures

This article aims to evaluate the results and outcomes of patients with highly comminuted radial head fractures, Mason III / IV type, treated surgically by arthroplasty with a cemented modular radial head prosthesis. A fracture of the radial head with a high degree of comminution left untreated can lead to complex functional impairment in which both elbow flexion and extension and also the pronation / supination of the forearm are limited, all of which will affect their daily activities. Management of radial head fractures should be based on both injury-specific factors and patient factors. Injury-specific factors include fracture size, displacement, rotation block, and associated injuries. Patient factors include age, associated injuries, bone quality, and activity level. Six patients underwent surgery for highly comminuted radial head fractures. All participants were followed up to 36 months postsurgery. A final review was carried out at 12-36 months after surgery when clinical, functional and imagistic assessment was performed. Functional results were very good; stability and ROM data obtained were within normal limits. Surgical treatment using modular radial head prosthesis offered excellent results, the elbow mobility being in the normal range and patients requiring a short period of recovery to achieve these parameters.

Outcome of Radial Head Arthroplasty in Comminuted Radial Head Fractures: Short and Midterm Results.

Background:Comminuted radial head fractures are often associated with secondary injuries and elbow instability.Objectives:The aim of this retrospective study was to evaluate how well the modular metallic radial head implant EVOLVE® prosthesis restores functional range of motion (ROM) and stability of the elbow in acute care.Patients and Methods:Eighty-five patients with comminuted radial head fractures and associated injuries received treatment with an EVOLVE® prosthesis between May 2001 and November 2009. Seventy-five patients were available for follow-up. On average, patients were followed for 41.5 months (33.0: 4.0 - 93.0). Outcome assessment was done on the basis of pain, ROM, strength, radiographic findings, and functional rating scores such as Broberg and Morrey, the Mayo elbow performance index (MEPI), and disabilities of the arm, shoulder and hand (DASH). Our study is currently the largest analysis of clinical outcome of a modular radial head replacement in the literature.Results:Overall, there were 2 (2.7%) Mason II fractures, 21 (28%) Mason III fractures, and 52 (69.3%) Mason IV fractures. Arbeitsgemeinschaft fur osteosynthesefragen (AO) classification was also determined. Of the 85 patients in our study, 75 were available for follow-up. Follow-up averaged 41.5 months (range, 4 - 93 months). Average scores for the cohort were as follows: Morrey, 85.7 (median 90.2; range 44.4 - 100); MEPI, 83.3 (85.0; 40.0 - 100); and DASH 26.1 points (22.5; 0.0 - 75.8). Mean flexion/extension in the affected joint was 125.7°/16.5°/0° in comparison to the noninjured side 138.5°/0°/1.2°. Mean pronation/supination was 70.5°/0°/67.1° in comparison to the noninjured side 83.6°/0°/84.3°. Handgrip strength of the injured compared to the non-injured arm was 78.8%. The following complications were also documented: 58 patients had periprosthetic radioluceny shown to be neither clinically significant nor relevant according to evaluated scores; 26 patients had moderate or severe periarticular ossification, and scored substantially worse according to MEPI and Morrey. Four patients required revisional surgery due to loosening of the prosthesis and chronic pain. In addition, one patient required a neurolysis of the ulnaris nerve, one developed a neobursa, and one had extensive swelling and blistering. The time interval between injury and treatment appeared to have an effect on results. Thirty-five patients were treated within the first 5 days after accident and showed better results than the 40 patients who were treated after 5 days.Conclusions:Comminuted radial head fractures with elbow instability can be treated well with a modular radial head prosthesis, which restores stability in acute treatment. The modular radial head arthroplasty used in this study showed promising findings in short to midterm results.

Study of role of prosthetic replacement for comminuted fracture of head of radius

Objective: We had evaluated our experience in the treatment of Morrey Modified Masons type III and IV radial head fractures with radial head prosthesis. Materials and Methods: From April 2011 to September 2014, modular radial head prostheses were performed in thirty patients. There were twenty female and ten male with mean age of forty years. The follow-up was a mean of 25 months. Fractures of the radial head have been classified by Morrey Modified Masons classification. The indications for a radial head replacement were type III fractures in 24 cases, type IV fractures in 6 cases, and comminuted radial fracture associated with disruption of the medial collateral ligament in 3 cases. Patients were assessed postoperatively and on follow-up based on Mayo Elbow Performance Index (MEPI) Score. Results: By using the MEPI, out of thirty cases, twenty cases had excellent results, seven cases had good results, two cases had fair results, and one case had poor result. Twenty-eight cases had no complications, one case had infection, and one case had implant failure. Conclusion: Modular radial head prosthesis can be used successfully for treatment of the Morrey Modified Masons type III and IV radial head fractures.

Clinical and radiologic outcomes of pyrocarbon radial head prosthesis: midterm results

The modular pyrocarbon (MoPyC) radial head prosthesis (Tornier, Saint-Ismier, France) is a monoblock modular radial head prosthesis. This study assessed midterm outcomes after implantation of the prosthesis. A retrospective study was conducted of a consecutive cohort of 65 patients who underwent radial head replacement with the MoPyC prosthesis from January 2006 to April 2013. Indications were fractures, early or late failures from orthopedic or fixation treatments, and revisions after another implant. Patients were observed for >2 years for range of motion, pain, and stability; function by the Mayo Elbow Performance Score (total score, 100) and grip strength were assessed. Quality of stem implantation, bone resorption around the neck, and periprosthetic lucency were noted and quantified on radiographs. Capitellum shape and density as well as humeroulnar aspect (river delta sign) were evaluated. Complications and revision procedures were noted. We evaluated 52 of 65 patients (mean follow-up, 46 ± 20 months; range, 24-108). The Mayo Elbow Performance Score was 96 ± 7; pain score, 42 ± 7/45; and motion score, 18 ± 2/20. Function and stability were excellent. Radiology revealed 92% of patients with cortical resorption around the neck without mechanical failure. Bone resorption was mostly anterior and lateral; it resolved within the first year and thereafter was stable. Eight patients underwent revision surgery for stiffness. No implant failures were noted. Results of the MoPyC radial head prosthesis appear to be satisfactory. Bone resorption around the neck (stress shielding) is frequent and stable after 1 year and does not impair stem fixation. The MoPyC prosthesis appears to be a reliable solution for replacing the radial head.

Modular prosthesis replacement for comminuted and unreconstructable radial head fractures

Objective To analyze the results of modular prosthesis replacement for treatment of comminuted and unreconstructable radial head fractures associated with other elbow fractures and sof-tissue injuries. Methods From November 2009 to March 2011,22 patients with comminuted radial head fracture of Mason type Ⅲ were treated with Acumed modular prosthesis replacement. Repair of collateral ligaments and associated elbow fractures was carried out simultaneously.They were 16 men and 6 women,with an average age of 41.5 years (from 21 to 62 years).The left side was involved in 9 cases and the right in 13.One patient was associated with posterior olecranon fracture-dislocation of Monteggia type Ⅱ,13 with elbow terrible triad,one with elbow dislocation but without coronoid process fracture,3 with Essex-Lopresti injury and 4 with medial collateral ligament injury.The coronoid process fracture was fixated with Kirschner wire and the proximal ulnar fracture with plate and screw.Hinged external fixators were used in 2 cases of elbow terrible triad.Patients were evaluated by the Mayo Elbow Performance Score (MEPS). Results The follow-ups averaged 12.95 months ( range,6 to 22 months ).One patient had disturbed elbow flexion of less than 90° due to prosthesis overstuffing,one patient had elbow instability in spite of full range of motion gained due to prosthesis understuffing,and one patient had elbow ankylosis at elbow flexion of 70° with a heterotopic ossification bridge.The results in the other 19 patients were good to excellent. Their average flexion was 131.5°±4.4° (from 130° to 140°),average extension 5.4°±6.3° (from 0 to 20°),average range of extension-flexion motion 126.1 ° ± 7.7° ( from 120° to 140°),average pronation 81.6° ± 6.4° ( from 70°to 90°),average supination 85.6° ± 3.1° (from 80° to 90°),and average range of rotation 167.2° ± 8.2°(from 150° to 180°).Their mean postoperative MEPS score was 94.2 ± 5.1 points (from 85 to 100points). Conclusions The Acumed modular radial head prosthesis offers 200 standard combinations (10left and 10 right stem options with 5 diameters and 4 collar height options) to accommodate different sizes and provide proper restoration of the overall length of the radius,replicates natural radial head geometry,provides improved articulation with the capitellum,prevents loosening and maintains the proper relationship between the radial neck and the plane of the head.Consequently,it is a fine treatment option for radial head fractures of Mason type Ⅲ complicated with additional elbow fractures and soft-tissue injuries,but it can also lead to complications. Key words: Elbow joint; Fractures; Surgical procedures, operative; Arthroplasty, replacement

ALTERATION OF THE END-PLANE ANGLE IN PRESS-FIT CYLINDRICAL STEM RADIAL HEAD PROSTHESIS: AN IN VITRO STUDY

Many studies comparing the morphology of native radial head with the prosthesis have been published. However, there is limited information regarding the postoperative alignment of the articular surface following the radial head replacement. The purpose of this study is to evaluate the alteration of the end-plane angle in the modular radial head prosthesis with a press-fit cementless cylindrical stem. The study used 36 cadaveric radii. The press-fit size prosthesis with cylindrical stem was inserted into each specimen. The end-plane angles of the radial head before and after prosthetic replacement, were measured in coronal and sagittal planes with a digital inclinometer. The data were analyzed by paired t-test. From paired t-test, there were statistically symmetrical end-plane angles before and after radial head replacement in both coronal and sagittal planes (p-value < 0.01). The mean of radial head end-plane angle alteration in the coronal plane was 3.62° (SD, 2.76°) (range, 0.3°-8.9°). In the sagittal plane, the mean of alteration was 5.85° (SD, 3.56°) degrees (range, 0.3° - 14.2°). The modular radial head prosthesis with cylindrical stem is in vitro able to restore the native end-plane angles of radial heads statistically when used in a press-fit fashion.

A primarily overlooked and incorrectly treated Essex-Lopresti injury: what can this lead to?

What result can one expect in treating an Essex-Lopresti lesion--a rare complex combination injury of the forearm consisting of a radial head fracture and a rupture of the interosseous membrane--which failed to be identified at first? We report on a 45-year-old poly traumatized patient in which a primary Essex-Lopresti injury was overlooked following a dislocated radial head fracture. A radial head resection followed by an ulna-shortening osteotomy was performed with disastrous consequences at another clinic. As a result of persistent instability in the distal radioulnar joint, we implanted a mono-polar radial head prosthesis, which was subsequently changed as a result of a loosening of the prosthesis and persistent complex instability and pain in the area of the entire forearm, while an ulna osteotomy had to be carried out to correct this. This prosthesis also loosened, which destroyed the capitulum humeri. It was only after a specially designed modular radial head prosthesis with a capitulum shield was implanted and an elapse of 5(1/2) years of the illness that permanent stability could be achieved on the forearm and the pain experienced by the patient eliminated while at the same time the patient regained a moderate degree of functioning and grip strength. An overlooked primary and ultimately initially incorrectly treated Essex-Lopresti injury can degenerate into a real therapeutic disaster. Years of illness and multiple corrective operations which only serve to limit the collateral damage caused by the wrong therapy strategy and ultimately only lead to restoration of moderate function. The crucial factor is an early diagnosis. Then a radial head prosthesis should first be implanted in an operation in order to prevent an additional proximal migration of the radius and to move the distal radioulnar joint into the proper anatomical position.