AN INVITRO STUDY OF AN INTRAARTICULAR AND EXTRAARTICULAR RECONSTRUCTION IN THE ANTERIOR CRUCIATE LIGAMENT DEFICIENT KNEE

The biomechanical effectiveness of an extraarticular ACL reconstruction, an intraarticular ACL reconstruc tion, and the combination of these on both anterior stability and internal rotational stability of the ACL de ficient knee was investigated in six cadaver knees. The extraarticular reconstruction consisted of the Müller anterolateral femorotibial ligament iliotibial band teno desis, and the intraarticular reconstruction used the middle third of the patellar tendon in the manner of Clancy. The extraarticular reconstruction was found to over- constrain internal tibial rotation of the ACL excised knee between 30° and 90° (P < 0.05). While the isolated extraarticular reconstruction did not return normal an terior stability to the ACL deficient knee (P < 0.05), it did significantly reduce the anterior laxity of the ACL deficient knee between 30° and 90° of knee flexion (P < 0.05). For the combined reconstruction, the intraarticular procedure was performed and then only enough ten sion was applied to the extraarticular reconstruction to take up slack in the tenodesis without shifting the rotatory position of the tibia from that produced by the intraarticular procedure alone. Neither the intraarticular reconstruction nor the combined procedure resulted in any significant shifts from normal (P < 0.05) in the rotatory position of the unloaded tibia; during loading neither resulted in rotational displacements significantly different from normal; and both of these procedures reduced the increased anterior laxity of the ACL defi cient knee to a level not statistically different from normal. Because the extraarticular reconstruction shared the load when performed with the intraarticular reconstruc tion as part of a combined procedure, we concluded that it would be useful as an adjunctive procedure in appropriate clinical situations. © 1990, SAGE Publications. All rights reserved.