Reliability of lower extremity alignment measurement using radiographs and PACS.

PURPOSE: Lower extremity alignment is an important consideration prior to cartilage surgery and/or osteotomy about the knee. This is measured on full length standing hip to ankle radiographs, which has traditionally been done using hard copy radiographs. However, the advent of PACS (Picture Archiving and Communication Systems) has allowed these measurements to be done on computer based digital radiographs. The objectives of this study were to evaluate the intra- and inter-observer reliability of lower limb alignment measures manually obtained from hard copy radiographs versus using the Philips Easy Vision system, and to assess the subjective ease of use for the two methods. METHODS: Forty-two patients who underwent surgery and who had a standing hip to ankle radiograph on file were identified. Four raters, including two radiologists and two orthopaedic surgeons, measured each hard copy radiograph and computer image on two separate occasions. Three measurements were recorded for each hard copy radiograph and computer image-width of tibial plateau, the distance from the medial aspect of the tibial plateau to the weight-bearing line, and the mechanical axis. RESULTS: All correlations for this study were high. For tibial plateau data, the hard copy radiographs compared to PACS demonstrated intra-class correlation coefficients (ICC) ranging from 0.93 to 0.99 for inter-rater reliability for the four raters. The ICC for intra-rater reliability for hard copies ranged from 0.90 to 0.99 and for PACS from 0.94 to 0.99. The inter-rater data comparing raters ranged from 0.87 to 0.98 for hard copy radiographs and from 0.98 to 0.99 for PACS. For mechanical axis data, the ICC for hard copy radiograph compared to PACS ranged from 0.93 to 0.97 for the intra-rater reliability for the four raters. The intra-rater reliability for mechanical axis data on hard copy radiograph ranged from an ICC of 0.86 to 0.96, and for PACS the ICC ranged from 0.93 to 0.99. The inter-observer data for hard copy radiographs using the mechanical axis ranged from 0.88 to 0.94 and for PACS ranged from 0.93 to 0.97. The physicians rated PACS as statistically significantly easier to use when compared to hard copy (P = 0.03). CONCLUSION: Evaluation of lower extremity alignment using two techniques prior to knee surgery was found to have higher inter- and intra-observer reliability using PACS software. PACS is now used prior to cartilage surgery and/or osteotomy to measure both alignment and the location of the weight bearing line on the tibial plateau both before and after surgery. LEVEL OF EVIDENCE: Diagnostic study, Level I.

Correlation of radiographic and arthroscopic findings with rotator cuff tears and degenerative joint disease.

The purpose of this study was to identify early signs of rotator cuff tear and glenohumeral articular cartilage degeneration by using conventional radiography. A non-weighted anteroposterior oblique and a weighted active abduction view were evaluated for superior humeral migration and matching degenerative changes at the inferolateral acromion and superior aspect of the greater tuberosity in 40 patients who underwent shoulder arthroscopy. Measurements of the glenohumeral distance were performed. Surgical reports were reviewed to determine rotator cuff and glenohumeral articular cartilage status. Matching degenerative changes correlate with complete rotator cuff tear (P =.04); superior migration does not. Severe glenohumeral cartilage loss correlates with narrowing of the superior joint space on the anteroposterior oblique radiograph (P =.02) and with narrowing of the mid joint space on the active abduction view (P =.05). Both glenohumeral articular cartilage degenerative change and rotator cuff injury, before formation of typical sequelae of chronic rotator cuff tear, can be detected with the use of conventional radiography.