[Radiologic and MRI evaluation of intra-articular ligamentoplasty using a patellar tendon. Correlations with anatomical results].
BACKGROUND
the purpose of this study was to evaluate the influence of the graft positioning on the clinical outcome and MRI signal of the graft as well, following ACL reconstruction using the central one-third of the patellar tendon.


METHODS
twenty one patients having a chronic anterior instability sustained a modified Marshall-Mac Intosh procedure, while 15 having a subacute torn ACL had an ACL reconstruction using a free bone-patellar tendon-bone graft. The patients were retrospectively reviewed with a 1.8 year average follow-up (1-3 years). The clinical result was evaluated through the comparative range of motion, the residual laxity as measured with the KT 1000 arthrometer, and the pivot shift test. The roentgenographic analysis was performed from AP and ML views, made first on one-leg standing with the knee at 30 degrees of flexion, and then in "zero" extension with active quadriceps contraction. Lines were drawn to visualise the location of the tibial and femoral tunnels in relation to the tibial plateaus and the roof of the intercondylar notch represented by the Blumensaat line. The analysis of the AP IRM views of the graft allowed to discriminate between homogeneous and heterogeneous graft signals.


RESULTS
on lateral roentgenograms of normal knees it was found that the Blumensaat line crossed the surface of the medial tibial plateau at its anterior third, at 30 +/- 9 per cent (20-40 per cent range), demonstrating the variability of the intercondylar roof inclination. The range of motion was normal in 22 patients (group 1), 8 patients had a flexion deficit (group II), and 6 exhibited an extension deficit (group III). The residual laxity was similar in each group (p > 0.05). When comparing group III to group I, patients from group III had a tibial tunnel significantly more anterior with regard to the Blumensaat line (p < 0.02). In group III, all patients exhibited an heterogeneous MRI graft signal (p < 0.05), and the angle between the intraarticular part of the graft and the tibial tunnel was higher (p < 0.001). These findings were not observed in group II where the location only of the femoral tunnel seemed to influence the flexion deficit (p > 0.05).


CONCLUSIONS
this study demonstrated that the location of the tibial tunnel with regard to the roof of the intercondylar notch, when the knee is in "zero" extension, was the most relevant parameter controlling the extension deficit resulting from a graft impingement. No relation was found between the tibial tunnel location with regard to the tibial plateaus and the mobility deficit. Graft impingement also was always associated with an heterogenous graft MRI signal.


CONCLUSIONS
when reconstructing the ACL care must be taken when inserting the K-wire aimed to guide the tibial drill, to obtain a proper position with regard to the roof of the intercondylar notch. The K-wire location must be checked in "zero" extension. Intra-operative X-rays may help.
Djian
P
P
Service de chirurgie Orthopédique et Traumatologique, hôpital Saint-Louis, Paris.
Christel
P
P
Roger
B
B
Witvoet
J
J
D016118:Anterior Cruciate Ligament / Q000601:surgery*; D000070598:Anterior Cruciate Ligament Injuries; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007593:Joint Instability / Q000175:diagnosis / Q000601:surgery*; D007718:Knee Injuries / Q000175:diagnosis / Q000601:surgery*; D007719:Knee Joint / Q000033:anatomy & histology / Q000000981:diagnostic imaging*; D008279:Magnetic Resonance Imaging; D008297:Male; D010329:Patella / Q000033:anatomy & histology; D011859:Radiography; D016059:Range of Motion, Articular; D012189:Retrospective Studies; D013710:Tendons / Q000637:transplantation
Evaluation radiologique et IRM des ligamentoplasties intra-articulaires utilisant le tendon rotulien. Corrélations avec les résultats anatomiques.