The anterior femoral cortical line (AFCL) is an anatomical landmark which has been used by the senior author for 20 years to assess femoral rotation in over 4000 TKR's. The AFCL describes the alignment of the anterior cortex of the distal femur proximal to the trochlear articular cartilage. The AFCL was compared with the surgical epicondylar (SEA), anteroposterior (Whiteside's line) and posterior condylar (PC) axes using 50 dry-bone cadaveric femora, 16 wet cadaveric specimens, 50 axial MRI's and 58 TKR patients intra-operatively. In the dry-bone/cadaveric femora (measuring relative to the SEA the AFCL and Whiteside's AP axis were 1° externally rotated and the PC axis was 1° internally rotated. By MRI (relative to the SEA) the AFCL was 8° internally rotated, Whiteside's was 2° externally rotated and the PC axis was 3° internally rotated. In the clinical study (measuring relative to a perpendicular to Whiteside's line alone) the AFCL was 4° degrees internally rotated, which equates to 2-3° of internal rotation relative to the SEA. The AFCL is another axis, completing the ‘compass points’ around the knee. It may prove particularly useful when one or all of the other reference axes are disturbed such as in revision TKR, lateral condylar hypoplasia or where there has been previous epicondylar trauma. We suggest building in 5° external rotation with respect to the anterior femoral cortical line for femoral component rotation.
In the clinical trial, 58 consecutive patients undergoing total knee arthroplasty were included. After a routine exposure the AP axis was marked on each distal femur. The AFCL was then identified and the anterior femoral cortical cut was made parallel to this line. The angle between this cortical cut and the perpendicular to the AP axis was measured using a sterile goniometer. In the MRI study, 50 axial knee images were assessed and the most appropriate slice/s determined in order to identify the AFCL and the other 3 reference axes and then their relationship was measured by an on-screen goniometer.
By MRI and with respect to the epicondylar axis, the AFCL was a mean 5° externally rotated (SD= 3), White-side’s Line was 1° externally rotated (SD = 2) and the posterior condylar axis was 3° internally rotated (SD = 2). In the clinical study in 8 patients it was impossible to draw the AP axis because of dysplasia or destruction of the trochlea by osteoarthrosis. In the remainder the mean difference between the anterior femoral cortical line and Whiteside’s AP axis was 4.1 degrees internally rotated (SD = 3.8°). The lateral release rate for this cohort was 4%. Conclusion: The anterior femoral cortical line provides an additional reference point, completing the ‘compass points’ around the knee. It has been shown in this study to be reliable in the laboratory, on MRI and in a clinical setting for assessing rotation of the femoral component. It may prove particularly useful when one or all of the other reference axes are disturbed such as in revision TKR, lateral condylar hypoplasia or where there has been previous epicondylar trauma.
Arthrofibrosis following ACL reconstruction prevents the patient from regaining full knee movement postoperatively. Our aim was to determine whether acute reconstruction (performed within 3 weeks of injury) is associated with an increased risk of arthrofibrosis compared with chronic reconstruction (performed more than 8 weeks after injury). We performed a prospective study of 114 patients who underwent a patellar tendon ACL reconstruction: 62 patients underwent acute reconstruction and 52 patients underwent chronic reconstruction. All patients were operated on by a single surgeon using a standardised arthroscopic technique and accelerated rehabilitation programme. All patients were assessed independently by an experienced physiotherapist at an average of 7 months post-operatively. Range of motion, stability, muscle strength and functional scores were measured. There was no significant difference in the incidence of arthrofibrosis between the acute and chronic groups. Flexion of less than 125° or a loss of extension of more than 10° occurred in 8 (12.9%) of the acute group and in 9 (17.3%) of the chronic group. All knees were clinically stable, but the mean KT1000 difference was 1.21mm in the acute group and 1.89mm in the chronic group (p<
0.05). There were no significant differences in muscle strength or functional scores between the two groups. There were significantly more meniscal injuries (65% versus 31%) and chondral lesions (31% versus 18%) in the chronic group. Acute ACL reconstruction is not associated with an increased risk of arthrofibrosis. However, it is associated with increased stability and less meniscal and chondral pathology. This study suggests that the optimum time for ACL reconstruction is within the first 3 weeks after injury.
28 knees underwent full clinical and radiological review at a mean of 25.8 months post-operatively, using the Hospital for Special Surgery Score and the Knee Society Score. 2 patients were interviewed by phone with recent radiological follow-up. One patient had died from unrelated causes.
The mean pre-operative alignment for the primary arthroplasties was 28° for the varus and 32° for the valgus knees. The mean postoperative alignment was 7°. The mean Hospital for Special Surgery score was 72.4 for primary arthroplasties and 72.7 for revision surgery. The mean Knee Society Knee Score was 79.8 and 75.1 respectively, and the mean Functional Score was 60.8 and 49.4 respectively. The latter reflects the elderly age, multiple joint involvement and constitutional status (including rheumatoid arthritis) of many of these patients. 4 patients experienced retropatellar pain. One patient with severe rheumatoid developed sepsis of the revision implant. Difficulties with tibial tray lateralisation and stem fixation will be discussed.
29 knees underwent full clinical and radiological review, using the Hospital for Special Surgery Score (HSS) and the Knee Society Score. One patient was interviewed by phone with recent radiological follow-up. One patient died of unrelated causes.
