Background: The synovial folds of the lateral atlanto-axial joints have not previously attracted significant radiological attention, being small and not routinely demonstrated on conventional MR images. However, they are considered to be a potential source of neck pain and disability, especially following whiplash injury.

Purpose: The purpose of this study was to develop an imaging protocol and measurement technique to determine the normal morphology of the synovial folds in vivo and establish normative values for their dimensions.

Methods: MR images of the cervical spine of 17 volunteers aged 20 to 50 years (mean 31.1, SD 5.9 years) were acquired using a 1.5T scanner. Seed growing and thresholding methods were used to identify the synovial folds and quantify their dimensions.

Results: The median volume of the right ventral and right dorsal synovial folds was 92.01 mm3 and 76.44 mm3, respectively. Left ventral and left dorsal synovial fold median volume measured 79.26 mm3 and 56.44 mm3, respectively. There was a significant difference in volume between the ventral and dorsal synovial folds of the right and left lateral atlanto-axial joints (χ2(3)=17.54, P=.000). The test-retest reliability of the measurement technique was ICC 0.99 and the inter-examiner reliability ICC 0.80.

Conclusion: This study is the first to establish a MR imaging protocol to visualise the synovial folds of the lateral atlanto-axial joints in vivo and quantify their morphology. The normative values established in the present study provide the basis for future studies to investigate the role of the synovial folds in patients with neck pain.

The DTC approach to patient management aims to decrease waiting list times and length of stay (LOS). To implement a reduction in the LOS it is imperative that suitable patients are selected. Factors such as co-morbidity and social support are important but other factors may also influence LOS.

To investigate if pre-operative measures of function were predictive of length of stay for patients treated in a Diagnostic & Treatment Centre for elective hip arthroplasty. The first 75 patients treated by the DTC were assessed pre-operatively recording timed measures of function for sit-to-stand, and stair climbing as well as ratings of pain and the WOMAC questionnaire. These measures were compared with the LOS for patients and their functional outcome at 6 weeks after discharge.

Linear regression was used to examine the influence of the measures on LOS. T-tests were used to compare the outcome at 6 weeks for pain and function between patients discharged within 5 days versus > 5 days.

The mean age was 65 years (39 – 80 years SD 8.4); 33 male and 42 female. Mean LOS was 6 days (4–14 SD 1.8), 52 % reached the DTC target of discharge on the 5th day. Regression analysis showed sit-to- stand was the best predictor of LOS (R2 = 46.7%) followed by WOMAC pain and climbing stairs. There were no significant differences in the pain or function scores at 6 weeks for patients discharged at 5 days or later.

Conclusion: There was a linear relationship between pre-operative sit-to-stand and LOS. The timed measures were simple to perform and patients could be tested in their own homes. Early discharge did not result in poorer self-reported outcome at 6 weeks. The routine measurement of sit-to-stand may be useful to clinicians as a prognostic indicator for treatment allocation and planning.