We report a retrospective study of the major complications following one-stage and two-stage bilateral unicompartmental knee replacements (UKR). Between 1999 and 2008, 911 patients underwent 1150 UKRs through a minimally- invasive approach in our unit. Of these, 159 patients (318 UKRs) had one-stage bilateral UKR and 80 patients (160 UKRs) had two-stage bilateral UKRs. The remainder were unilateral UKRs.

The bilateral UKR groups were comparable in age and ASA grade, but more females were in the two-staged group (p=0.019). Mechanical thromboprophylaxis was used in all cases. Major complications were recorded as death, pulmonary embolus, proximal deep vein thrombosis (DVT) and adverse cardiac events within 30 days of surgery.

No statistical differences between the groups were found regarding operating surgeon, tourniquet time or minor complications (excepting distal DVT). Anaesthetic times were greater for the two-stage group (p= 0.0001). Major complications were significantly more common with one-stage bilateral UKR (13 patients, 8.2%) compared to two-stage bilateral UKR (no patients) (p=0.005). Distal DVT was more frequent in the two-stage group (p=0.036).

This series reports significantly higher risks of major complications are associated with one-stage bilateral UKR when compared to two-stage bilateral UKR. There is no evidence that the addition of chemical thrombo-prophylaxis would change this risk. We advocate caution before undertaking a one-stage bilateral UKR.

Aim: To demonstrate that a multidisciplinary protocol reduces both in-patient stay and the need for out-patient physiotherapy following minimally invasive (MIS) uni-condylar knee replacements (UKR).

Methods: The data for hospital stay was collated for a consecutive group of primary UKR at our institution during 2002. We then compared this with a consecutive group of patients seen in a dedicated physiotherapist run clinic, with the provision of brochures and a “patient experience video”, with input from nurses, physiotherapists, anaesthetists, and surgeons, as well as time of expected discharge. The data was compared between informed (dedicated pre-operative assessment and patient video) and uninformed patients (standard pre-operative care).

Results: Total of 57 patients were initially assessed and compared with 81 patients after introduction of specific pre-op care pathway. Average hospital stay was reduced from 3.7 days to 2.1 days, with 60% going home within 24 hours.

Discussion: By changing the preconception of long hospital stays after arthroplasty ingrained in patients and staff we have reduced hospital stay significantly. Major factors contributing to this include the team approach, patient and ward staff education, perceptions of discharge and the inclusion of specific local anaesthetic techniques, and a minimally invasive approach. Delays in discharge include the geography of the region.

Anterior knee pain attributable to the patellofemoral joint and extensor mechanism dysplasia is a common presentation to Orthopaedic surgeons. Plain radiology is likely to remain the primary investigation of the knee in most centres, but most of the radiological features of extensor mechanism dysplasia are time consuming and difficult to measure reproducibly. 137 consecutive symptomatic knees aged under 30, referred to an Orthopaedic surgeon were studied in order to identify a rapid and reproducible marker for those knees worthy of further in-depth analysis.

Overall, 67 knees (49%) had at least one radiological abnormality and 70 (51%) were considered ‘normal’. There were 5 Dejour Type3 dysplasias of the femoral trochlea, 9 Type2 and 12 Type1. There were 49 cases of patella alta and 5 of patella infera. Four knees had an abnormal lateral patellofemoral (patellar tilt) angle. 15 knees had more than one abnormality. The classification of trochlear dysplasia was difficult and showed poor reproducibility. This was also true for the measurement of lateral patellofemoral angles. Patellar height was more easily measured but took time. The sulcus angle emerged as an easily and rapidly measurable feature that was reproducible and was closely related to the other features of extensor mechanism dysplasia.

The sulcus angle offers a rapid and reliable ‘screening’ measurement on knee radiographs. A normal sulcus angle suggests that seeking the other radiological markers of extensor mechanism malalignment is unlikely to reveal additional useful information. Other diagnoses can then be sought. The more abnormal the sulcus angle, the more severe the other features of extensor mechanism dysplasia are likely to be. Further detailed measurements can then help to define the most appropriate surgical correction.

A prospective clinical investigation to determine the optimum knee flexion angle for the ‘skyline’ patellofemoral joint radiograph.

Plain radiography of the patello-femoral joint includes the axial or ‘skyline’ radiograph. The optimum knee flexion angle for making this image remains unclear.

We therefore performed a prospective clinical study in which patients underwent three skyline radiographs with knee flexion angles of 30(or minimal flexion), 50 and 90 degrees. The patients were new patients, aged between 12 and 30, presenting to a knee clinic with anterior knee pain. Two observers evaluated the radiographs, making a standardised series of measurements. Blinding was organised so that the observers were unable to use any information other than the radiographic image alone. One observer evaluated all the films on two separate occasions to allow calculation of intra- and interassessor agreement.

There were 67 knees from 46 patients. There was a high level of intra- and inter-observer agreement. There were a number of patients in which the radiographic appearance of the patello-femoral varied markedly between the different views; in all cases the abnormality was best demonstrated by the 30-degree view. There were however a number of minimal flexion views in which the film contained incomplete information because part of the patello-femoral joint was missing from the image.

We conclude that whilst a minimal flexion skyline view is the most sensitive method for the detection of patellar tilt and subluxation, not all knees can be successfully imaged at the required position. A flexible approach is therefore needed, to obtain satisfactory images at minimal flexion.