We report on the 5 year results of a randomized study comparing TKR performed using conventional instrumentation versus electromagnetic computer-assisted surgery.

This study analysed patient reported outcome measures (PROMs) at 5 years utilising the American Knee Society Score (AKSS), Oxford Knee Score (OKS), the Short Form 36 score and range of motion (ROM). Of the 200 patients enrolled 125 completed 5 year follow up, 62 in the navigated group and 63 in the conventional group. There were 28 deceased patients, 29 withdrawals and 16 lost to follow-up.

There was improvement in clinical function in most PROMs from 1-5 year follow up across both groups. OKS improved from a mean of 26.6 (12–55) to 35.1 (5–48). AKSS increased from 75.3 (0–100) to 78.4 (−10–100), SF36 from 58.9 (2.5–100) to 53.2 (0–100). ROM improved by an average 7 degrees from 110 degrees to 117 degrees (80–135). There was no statistically significant difference in PROMs between the groups at 5 years.

Patients undergoing revision surgery were identified from the dataset and global PACS. There were no revisions within 5 years in the navigated group and 3 revisions in the conventional group, two for infection and one for mid-flexion instability, giving an all cause revision rate of 3.06% at 5 years for this group.

There appears to be no significant advantage in clinical function for patients undergoing TKR for OA of the knee with electromagnetic navigation when compared to conventional techniques. There may be an advantage in reducing early revision rates using this technology.

Limb length deficiency, secondary to trauma or infection, is a common reason for referral to our tertiary service. After experiencing troubles with the Intramedullary Skeletal Kinetic Distractor (ISKD), we changed implant to the magnet operated Precice nail. We evaluated the safety and reliability of this novel device and compared it to our early ISKD results.

To minimise variables, we selected femurs only. In total, we reviewed medical and radiographic records of 20 cases (8 ISKD, 12 Precise) from 2010–2015. At each postoperative visit, the accuracy and precision of distraction and complications were recorded. Accuracy reflected how close the measured lengthening was to the prescribed distraction at each postoperative visit. Precision reflected how close the repeated measurements were to each other over the course of total lengthening period. No patients were lost to follow-up (1–3.5 years).

With the Precice nail (2012–2015), 11/12 were male and 10/12 were caused by trauma. The mean age was 34. Mean total lengthening was 38mm (range, 29–53mm), with an accuracy of 98percnt; and precision of 92percnt;. All patients achieved target lengthening at a rate of 1mm lengthening per day. In one case, the Precice nail fractured and this was revised successfully. With the ISKD group (2010–2012), 8/8 had complications (magnet jamming, nail breakage, equinus contractures and claw toes), with 25percnt; achieving accurate lengthening and precision of 38percnt;.

Our results so far have justified our change in implant choice and, in our experience, support the Precice nail as being safe and precise.

Total knee arthroplasty (TKA) is an established and successful operation. However patient satisfaction rates vary from 81 to 89% 1,2,3. Pain following TKA is a significant factor in patient dissatisfaction 1. Many causes for pain following total knee arthroplasty have been identified 4 but rates of unexplained pain vary from 4 to 13.1% 5,6. Recently computerised tomography (CT) has been used to assess the rotational profile of both the tibial and femoral components in painful TKA

We reviewed 57 patients with an unexplained painful following TKA and compared these to a matched control group of 60 patients with TKA. Datum gathered from case notes and radiographs using a prospective database to identify patients. The CT information recorded was limb alignment, tibial component rotation, and femoral component rotation and combined rotation.

The two matched cohorts of patients had similar demographics. A significant difference in tibial, femoral and combined component rotation was identified between the groups. The following mean rotations were identified for the painful and control groups respectively. Tibial rotation was 3.46 degrees internal rotation (IR) compared to 2.50 degrees external rotation (ER)(p=0.001). Femoral rotation was 2.30 IR compared to 0.36 ER(p=0.02). Combined rotation was 7.08 IR compared to 2.85 ER(p=0.001).

This is the largest study presently in the literature. We have identified significant internal rotation in a patient cohort with unexplained painful TKA when compared to a matched control group. Internal rotation of the tibial component, femoral component and combined rotation was identified as a factor in unexplained pain following TKA.