Introduction

This study evaluated the reliability of radiographic qualitative and quantitative ulna trochlear notch sclerosis (TNS) tests that could be easily transferred to general practice. The objective was to increase the sensitivity of the radiological diagnosis of medial coronoid process disease (MCD).

Hypotheses

1.  Radiographic TNS tests would increase the accuracy and sensitivity of detecting MCD.

2.  Increasing TNS correlates to increasing severity of MCD as evaluated by Computed Tomography (CT).

Materials and Methods

Sixty-one dogs with MCD (121 elbows) were selected from the imaging database. The controls were 9 cadavers (18 elbows), confirmed at post mortem to be disease free. Dogs were excluded if another condition causing thoracic limb lameness was present. Standard International Elbow Working Group (IEWG) radiographs and CT scans were taken of each elbow.

Three observers independently assessed the radiographs and the CT scans at separate times. The presence of disease was confirmed by group consensus of the CT coronoid disease grade (table 1) combined with arthroscopic diagnosis when available (66/121). If the CT and arthroscopic diagnosis did not concur, then the arthroscopic diagnosis superseded.

Radiographs were assessed using various tests: osteophyte grade (0-3), coronoid grade (0-3), TNS descriptive grade (0-3) and TNS ratio. This ratio was obtained directly from the lateral neutral radiograph, measuring the depth of sclerosis at the level of the disto-cranial margin of the humeral condyles and then measuring the cranio-caudal ulna depth (outer cortex to outer cortex).

Inter-observer agreement was assessed using kappa statistics and intraclass correlation coefficients. Kruskal-Wallis tests were applied to assess for significance.

Results

There was general agreement between all observers for all tests p=<0.001.

There was a significant difference between control and diseased groups with respect to TNS, p=<0.001.

The TNS descriptive and ratio scale both increased the overall accuracy and sensitivity of diagnosing coronoid disease above the other radiographic tests (Table 2).

Radiographic TNS significantly increased with increasing CT coronoid disease grade p=<0.001.

Discussion

The finding that TNS increases the accuracy and sensitivity of diagnosing coronoid disease is valuable to those that have neither a CT scanner nor arthroscopy readily available. The tests described in this study are easy to apply and require no sophisticated technology to detect sclerosis.

Table 1.

Table 2.