Radiologic assessment of glenohumeral relationship: reliability and reproducibility of lateral humeral offset.

BACKGROUND: It has been shown that anatomical reconstruction is an important step in achieving good function after shoulder arthroplasty. It is essential to reconstruct the distance between the coracoid process and greater tubercle as this relates to the moment arm of the deltoid and rotator cuff muscles. This study evaluated the reliability of measurement of the lateral humeral offset (LHO) on plain radiographs and on computed tomography (CT). METHODS: Four independent observers performed measurements of LHO on radiographs and CT from 26 patients awaiting shoulder reconstruction. The interobserver reliability and intraobserver reproducibility were assessed. RESULTS: Interobserver reliability and intraobserver reproducibility of LHO in axial CT scans were excellent. Plain radiography showed fair to excellent interobserver reliability and variable intraobserver reproducibility. CONCLUSION: CT is a reliable tool to measure LHO supporting its use in preoperative planning. When AP radiography is used for preoperative planning the examiner should be aware of its limitations and standardisation protocols should be considered.

Radial head arthroplasty for radial head fractures: a clinical and radiological comparison of monopolar and bipolar radial head arthroplasty at a mean follow-up of 6 years.

PURPOSE: The purpose of this study was to compare clinical and radiographic outcomes of bipolar and monopolar radial head arthroplasty in treatment of radial head fracture at a mean follow-up of 6 years. METHODS: A retrospective multicentre cohort study of 30 patients treated for unreconstructable radial head fractures. Patients were treated either with a cemented bipolar or an uncemented monopolar radial head arthroplasty. All patients included were evaluated with patient-rated outcome questionnaire, physical examination, and radiographic evaluation at a mean of 6 years (range, 2-12 years) postoperatively. RESULTS: There was no statistical difference in QuickDASH between the bipolar or monopolar groups. The majority of patients had no to little pain during rest. Neither flexion nor extension of the injured arm was significantly affected by the type of prosthesis. None of the patients in the bipolar group had any secondary surgery at the time of follow-up. In the monopolar group, four patients required removal of the arthroplasty. Signs of ulnohumeral degenerative changes were seen in the majority of patients in both groups (55% in the monopolar group, 92% in the bipolar group). CONCLUSION: In this retrospective cohort study comparing a bipolar and a monopolar radial head arthroplasty for treatment of radial head fractures, we found comparable functional outcome but more revision procedures in the monopolar group at a mean follow-up of 6 years.