Radiusköpfchen- und Radiushalsfrakturen: Aktuelle Literatur- und Evidenzlage

The cortical irregularity in the transition zone of the radial head and neck: a reliable radiographic sign of an occult radial head fracture

PURPOSE

Exclusion or detection of non-displaced radial head fractures can be difficult in radiographs, because they might lack conclusive radiographic signs, such as fracture lines or distracted articular fragments. Based on the typical injury mechanism of a radial head fracture, causing the head to hit the capitulum and leading to a depression of the anterolateral border of the radial head, we hypothesized that even slight cortical irregularities in the transition zone of the radial neck and head result from that depression and may be a reliable radiographic sign of an underlying radial head fracture. Secondarily, we tested the null hypothesis that the lack of cortical irregularities is sufficient to exclude a fracture of the radial head.

METHODS

84 patients with sets of anteroposterior and lateral radiographs of the elbow were identified from the database of a level 1 trauma center and divided into 2 groups. Group A was formed out of 42 patients with non-displaced radial head fractures, group B out of 42 patients without a history of previous elbow trauma, whose medical history also contained radiographic images. After the radial head was blackened, the transition zone of the radial neck and head was assessed by two attending orthopedic surgeons for presence of a cortical irregularity. The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of cortical irregularity were calculated for the assessment of radial head fractures. The kappa measure of agreement was utilized to evaluate interrater agreement.

RESULTS

The specificity was 87.80 and 97.56 %, respectively, its sensitivity 86.04 and 75.61 %. A high NPV (85.71 %; 80.00 %) and PPV (96.88 %; 88.10 %.) were observed. The interrater agreement for the proposed diagnostic method was high, with a Cohen kappa score of 0.737 (p < 0.001).

CONCLUSIONS

A cortical irregularity in the transition zone of the radial neck and head seems to be a reliable radiographic sign of an underlying radial head fracture. The absence of the cortical irregularity can be used to correctly identify a non-fractured radial head.

From radial head to radiocapitellar to total elbow replacement: A case report

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Overstuffing is a serious yet avoidable complication of radial head arthroplasty.

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Overstuffing severely alters elbow joint kinematics and leads to capitellar erosion.

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Radiocapitellar arthroplasty can be a salvage procedure in such cases.

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Limited clinical data is available thus far regarding radiocapitellar arthroplasty.

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The possibility for early failure due to ulnohumeral erosion has to be considered.

Introduction

Radiocapitellar arthroplasty represents a possible treatment option for isolated osteoarthritis of the radial column. We report the first case of early failure of this procedure.

Presentation of case

We present the case of a 41-year old male who sustained a terrible triad injury to his right elbow and subsequently underwent radial head arthroplasty. Due to overstuffing of the radial head prosthesis, capitellar erosion occurred and radiocapitellar arthroplasty was thus performed. Only one year later, conversion of the radiocapitellar replacement to total elbow arthroplasty was required as a result of progressive ulnohumeral osteoarthritis.

Discussion

According to the currently limited clinical data, radiocapitellar arthroplasty provides satisfactory results. However, biomechanical analysis shows that available prostheses do not sufficiently reproduce the radiocapitellar anatomy. The design of the prosthesis might thus have contributed to the rapid progression of ulnohumeral erosion following radiocapitellar arthroplasty although the poor outcome may also be attributed to the trauma itself along with the inadequate initial treatment.

Conclusions

The indication for radiocapitellar arthroplasty warrants careful consideration given the results of biomechanical analysis and the early failure due to progressive ulnohumeral erosion seen in the present case.