Introduction: The Distal metatarsal articular angle (DMAA) is a radiographic measure of orientation of the first metatarsal articular surface, it is frequently used in the management of hallux valgus. There is a great deal of conflict regarding accuracy, reproducibility and validity of the DMAA within the literature. This study aims to test the validity of the measurement of the DMAA from standard radiographs, to explore the trigonometric relationship of first metatarsal rotation and the DMAA and to assess inter-observer reliability.

Materials/Methods: 34 seperate dry cadaveric first metatarsal bones were mounted onto a customized light-box/protractor allowing controlled incremental changes in rotation and inclination. A series of 39 digital photographs were taken of each metatarsal in 5 degree increments of rotation between 30 degrees supination and 30 degrees pronation and 10, 20 and 30 degrees of inclination. Three reviewers performed blinded DMAA measurements from each image; the data was collated for statistical analysis.

Results: The data was analysed using a mixed effects linear model comparing the DMAA with rotation of the first metatarsal. A strong statistically significant trend of increasing score with increasing pronation is observed, the relationship of which is approximately linear. There is a strong effect of inclination, but the strength of this varies with rotation this is amplified at higher inclinations. Inter-observor error was noted in line with other studies, the linear relationship is maintained.

Discussion: This study has shown that the distal metatarsal articular angle varies significantly, in an almost linear pattern, with axial rotation of the first metatarsal. Inclination of the first metatarsal is also shown to affect the magnitude of the angle.

This study does not refute the distal metatarsal articular angle as an entity, but does confirm the inaccuracy of extrapolating the DMAA from plain AP radiographs.

Introduction and Aims: Allogenic blood transfusion is often required in lower-limb arthroplasty. The aims of this study were (1) to analyze the influence of anaemia on post-operative fatigue, hand grip strength, duration of in-patient physiotherapy and post-operative morbidity score (POMS) and (2) to investigate for prognostic factors to predict functional recovery following primary arthroplasty of the lower limb.

Patients and methods: This study was approved by the regional ethics committee. Two hundred patients (88 THR, 99 TKR and 13 hip resurfacing) were evaluated in this prospective trial. Blood haemoglobin concentration (Hb), hand grip strength and vigour scores using a validated fatigue questionnaire were estimated both preoperatively and at 3 days following surgery. Postoperative morbidity score (POMS) and the required duration of in-patient physiotherapy were also noted. The protocol for blood transfusion was for those with Hb less than 8 g/dL and/or post-operative symptoms attributable to anaemia.

Results: A greater fall in postoperative Hb correlated significantly with a greater reduction in post-operative vigour score (p=0.02). Also a greater fall in vigour score was found to correlate significantly with the duration of in-patient physiotherapy (p< 0.001). A reduction in Hb of > 4g/dL from the pre-operative Hb predicted a significantly higher reduction in vigour score (p=0.03). A weak correlation was seen between a fall in Hb and POMS (p=0.09).

A higher pre-operative Hb did not reduce the required duration of in-patient physiotherapy (p=0.72). There was no correlation between post-operative Hb and POMS (p=0.21) or required duration of in-patient physiotherapy (p=0.20).

A higher pre-operative grip strength predicted an early date of discharge by the physiotherapists (p=0.02).

Conclusion: We conclude that a fall in Hb of more than 4 g/dL has a detrimental effect on post-operative rehabilitation. Pre-operative grip strength measurements are valuable in predicting the rehabilitation potential of patients undergoing lower limb arthroplasty.