Abstract
Introduction
The legion knee revision system was designed as a follow and improvement to the Genesis II knee system- allowing for a surgeon directed femoral rotation as opposed to the in-built femoral rotation in the previous system.
This is a prospective review of consecutive patients who underwent knee revision surgery using the legion knee system.
Methods
Clinical and functional assessments were carried out preoperatively, one year and 2 years post op. Radiographic evaluation was done at 1 and 2years follow up. Standard knee scoring systems (American Knee Scores-AKS, and Oxford score were used for the clinical and functional evaluation of these patients. The WOMAC score was also used to assess for pain, stiffness and social function in these patients. The radiographic assessment included review of standing AP, lateral and skyline views. Figgie's method was used to measure the joint line reproduction. A difference of 5 mm (pre = op/post-op) was deemed satisfactory.
Results
Seventy-five consecutive patients underwent revision knee system- 38 male: 34 females with a mean age of 71.2 (50–87 yrs.). Mean BMI-26.03, (Range 11–50). We had a 2-year follow up for 32 patients Surgery was carried out at a single centre and performed by members of the Bristol knee group.
Indications for surgery in these patients- were aseptic loosening (38), instability (15), pain and stiffness (7), polyarthropathy (2), ligament laxity (3), peri-prosthetic fractures (3), and impingement (4)
The mean American Knee scores, and WOMAC scores at, 1 year and 2 years follow up showed significant improvements in pain and function. It was also noted that the mean oxford knee score improved from 14/48 pre-operatively to 34/48 at 2yrs. Radiographic assessment showed a mean AP coronal femoral angle of 95.3 degrees (range 89.6–99.9 degrees), coronal tibial angle of 90.1 degrees (Range 88–92 degrees). The mean sagittal femoral and tibial angles were 88.4 and 90.4 degrees respectively. Mean Kappa value for the inter observer reliability for the radiographic assessment was 0.50 showing agreement, with standard error measurement of 1.2. The joint line was reproduced in all cases.
Discussion
The short-term results with the Legion Knee revision system showed significant improvement in functional and pain scores in these patients irrespective of their indications for revision surgery.
Overall the legion system has showed good outcome scores that match or beat published series on revisions. It also showed a good ability to restore joint line. Ongoing work needed to refine indications and realistic outcomes for different diagnoses.
