X-ray evaluation of failed unicompartmental knee replacement

TECHNIQUE The Lyon Schuss view (an anteroposterior weight-bearing radiograph taken with the knee in 20–30 degrees flexion) offers greater accuracy in determining moderate to severe loss of joint space compared with the standard weight-bearing view with the knee fully extended3,4. This is particularly so in lateral compartment arthritis where the pattern of disease is different, ie the posterior part of the compartment is affected. Corresponding appearances of the same joint with a AP valgus stress view (Fig 1a) and Lyon Schuss view (Fig 1b) are seen in the adjoining figure. Use of the Lyon Schuss radiographic views when evaluating causes of failed UKR has not previously been described.