INTRODUCTION. One of the main goals of total knee arthroplasty (TKA) is to restore an adequate range of motion. The posterior femoral offset (PFO) may have a significant influence on the final flexion angle after TKA. The purpose of the present study was to compare the conventional, radiologic measurement of the PFO before and after TKA to the intra-operative, navigated measurement of the antero-posterior femoral dimension before and after TKA implantation. MATERIAL. 100 consecutive cases referred for end-stage knee osteo-arthritis have been included. Inclusion criteria were the availability of pre-TKA and post-TKA lateral X-rays and a navigated TKA implantation. There was no exclusion criterion. METHODS. Pre-TKA and post-TKA digital lateral X-rays were performed with fluoroscopic control of the superposition of both femoral. The PFO was defined as the distance between the anterior femoral cortex and the most posterior point of the femoral condyles (figure 1). The TKA was implanted with help of a navigation system. The standard navigated procedure involves a navigated palpation of the anterior femoral cortex just proximal to the trochlea (figure 2) and a navigated palpation of the most posterior point of both femoral condyles (figure 3), allowing computation of the pre-TKA navigated PFO. The post-TKA PFO was calculated according to the the antero-posterior position of the prosthetic trochlea in comparison to the anterior femoral cortex and the size of the femoral implant. Pre-TKA and post-TKA radiologic and navigated measurements of the PFO were compared with a paired Student t-test and calculation of the coefficient of linear correlation. The coherence between the data was analyzed according to Bland-Altman. The radiologic and navigated PFO changes were compared with a paired Student t-test and calculation of the coefficient of linear correlation. The sample size was calculated to allow detecting a 3 mm difference at a 0.05 level of significance and a power of 0.90. All statistical tests were performed at a 0.05 level of significance. RESULTS. The mean paired difference between pre-TKA radiologic and navigated measurement was 3.8 mm ± 4.1 mm (range, −5.2 to 17.9 mm) (p<0.001). There was a significant moderate positive correlation between both measurements (R² = 0.41, p<0.001). There was a good coherence between both measurements (R² = 0.04). The mean paired difference between post-TKA radiologic and navigated measurement was 5.9 mm ± 4.8 mm (range, −24.0 to 16.9 mm) (p<0.001). There was a significant moderate positive correlation between both measurements (R² = 0.51, p<0.001). There was a poor coherence between both measurements (R² = 0.11). The mean paired radiologic PFO change was 1.5 mm ± 5.2 mm. The mean paired navigated PFO change was −0.9 mm ± 4.0 mm (range, −14.0 to 12.2 mm) (p<0.001). There was a significant weak positive correlation between both measurements (R² = 0.21, p<0.001). There was a good coherence between both measurements (R² = 0.002). DISCUSSION. We observed a significant difference between radiologic and navigated results. This difference is likely to be clinically significant. CONCLUSION.
Aims. To study the outcomes of DVR plating for distal radius fractures. Methods. We prospectively studied all patients managed with a DVR plate, over a twelve-month period in 2006/07. All patients were seen in our dedicated research clinic at 2, 6, 12 and 26 weeks post-operatively. Physiotherapy started at 2 weeks post-operatively. Active range of motion (ROM) of the injured wrist was recorded at 6, 12 and 26 weeks and compared with the normal side. Standardised radiographs were taken at 2 and 6 weeks and compared with pre- and post-operative films for radial and volar angulations, relative radial length, ulnar variance and implant position. Patient satisfaction was measured with the Patient Rated Wrist Evaluation score (PRWE) at 6, 12 and 26 weeks. Results. 129 patients (male:female 1:3) with a median age of 59 years (92-17 years) were seen. Mean measurements of pre-operative films were of 16 degrees dorsal angulation, 15 degrees radial inclination, 7 mm relative radial length and +2mm ulnar variance. In comparison post-operative results were -6 degrees, +22 degrees, 11mm and 0mm respectively, which remained unchanged at 2 and 6 weeks. The mean comparative active ROM was 70%, 88% and 98% at 6, 12 and 26 weeks respectively. The PRWE Score showed a mild degree of disability at 6 weeks and only minimal disability at 12 and 26 weeks. There were two cases of lost fracture position and no case of deep infection. Conclusion. Our study suggests that the DVR locking plate provides excellent fracture stability, allowing for early rehabilitation, with minimal complications.
Background. Patellar instability is a complex, multi-factorial disorder. Radiological assessment is regarded as an important part of the management of this population. The purpose of this study was to determine the intra- and inter-rater reliability of common radiological measurements used to evaluate patellar instability. Methods. One hundred and fifty x-rays from 51 individuals were reviewed by five reviewers: two orthopaedic trainees, a radiological trainee, a consultant radiologist and an orthopaedic physiotherapist.
