[Replacement of the comminuted radial head fracture by a bipolar radial head prosthesis]

Fracture Pattern Influences Radial Head Replacement Size Determination Among Experienced Elbow Surgeons

BACKGROUND

Correct sizing is challenging in radial head replacement and no consensus exists on the implant's optimal height and width to avoid elbow stiffness and instability. Studies exists, suggesting how to appropriately choose the implant size, but the manner by which the fracture pattern influences the surgeons' operative choices was not investigated.

METHODS

The radial heads of four fresh-frozen cadaveric specimens were excised, measured, and fractured to simulate four patterns: three fragments (A); four fragments (B); comminuted (C); comminuted with bone loss (D). Nine examiners were asked to indicate first the maximum diameter of the radial heads with the help of dedicated sizing dishes and then the appropriate implant size with trial implants. Accuracy and precision were determined. A coefficient of variation was calculated and agreement was evaluated with the Bland-Altman method.

RESULTS

Accuracy and precision of radial head diameter estimation with dedicated sizing dish were 96.73% and 93.64%, (best pattern, D; worst, C). Accuracy and precision of radial head diameter estimation with trial implants were 99.71% and 90.66% (best pattern, A; worst, D). Frequent modifications occurred between the initial radial head size proposal based on the sizing dish and the radial head size chosen after use of the trial implants (47.2%).

CONCLUSIONS

Diameter estimation of radial heads with dedicated sizing dishes may be underestimated in comminuted fractures; when bone loss is present, this may lead to an overestimation, especially when using trial implants. Care is essential to determine the optimal size of the implant and to avoid overlenghtening and oversizing, which can be responsible for implant failure.

LEVEL OF EVIDENCE

Basic Science Study.

CLINICAL RELEVANCE

Knowledge of the manner by which the fracture pattern influences radial head replacement size estimation can help preventing overlenghtening and oversizing during this procedure.

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.

Functional outcomes post-radial head arthroplasty: a systematic review of literature

BACKGROUND

The present study was conducted to determine the quality and content of research on the functional outcomes and complications post-metal radial head arthroplasty (RHAP).

METHODS

A comprehensive search of medical databases for studies reporting on functional outcomes of patients undergoing metallic RHAP was conducted. The Structured Effectiveness Quality Evaluation Scale (SEQES) was used to evaluate quality of the studies.

RESULTS

We identified 21 Sackett's Level IV studies reporting on 391 radial heads. The mean duration of follow-up was 47.2 months and the mean (SD) age of patients was 48.4 years (6.9 years). The male to female ratio was found to be 1.05 : 1 and the dominant arm was involved in 54% of patients. When functional outcomes achieved post-RHAP were compared with normative scores, the comparison suggested that RHAP has good to excellent functional outcomes in short- to mid-term follow-up. The weighted mean (SD) Mayo Elbow Performance Score was 85.8 (4.1) (95% confidence interval 85.3 to 86.3). Incidences of implant removal (3.06%) and revision (2.22%) were found to be low.

CONCLUSIONS

There is consistent low-quality evidence of positive functional outcomes following RHAP. The heterogeneity of type of implant, patient characteristics and outcome measures used, along with an inadequate reporting of study details, restrict any definitive conclusions being made.