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Using computer navigation as a laxity measurement emerges as a new trend
Navigation can be used as a research tool or for technical assistance in ligament reconstruction.
Computer navigation can be a valuable and versatile tool in a surgeon’s armamentarium. Now, surgeons are using it to assess patients’ individual patterns of laxity for knee ligament reconstructions.
“We all have a computer in our office and in our homes and we know that they will become indispensible in our operating room to plan, perform and assess our ACL reconstructions,” Philippe D. Colombet, MD, said during his presentation at the American Academy of Orthopaedic Surgeons 75th Annual Meeting. “It will be invaluable as we move to the concept of a la carte surgery, [tailored] to redressing the patients’ individual patterns of laxity.”
Colombet noted that while surgeons get good results with ACL reconstruction, 14% to 30% of cases have postoperative residual pivot “glide” and in some cases the normal joint kinematics, and particularly rotational stability, are not fully restored. To this end, computer navigation may be useful to surgeons as a laxity measurement.
“The laxity measurement is a new trend,” Colombet said. “It is a new tool and a new option for navigation.” Navigated laxity examinations allow surgeons to perform anterior drawer and Lachman tests and assess the coupled rotational laxities and the global rotational laxity.
“What is very important is the use of navigation for the pivot shift,” Colombet said. With the results of the different laxity tests, surgeons can determine an individual patient’s laxity pattern and select better indications intraoperatively.
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Image: Colombet PD |
Technical assistance
In addition, computer navigation can be useful for providing technical assistance and used as a research tool. Colombet noted that there are many different types of computer-navigation software on the market and some are customized to allow surgeons to select different types of laxities to assess and have different treatment options for single- or double-bundle and revision procedures.
The equipment is also simple to use minimally or noninvasively, he said. “Many teams are working on noninvasive fixation for a rigid body which can be useful for the evaluation at the office.” Navigation also allows surgeons to perform isometry analysis and predict graft impingement.
In addition, the systems can aid surgeons in performing peripheral reconstructions such as lateral tenodesis and medial collateral ligament (MCL) reconstructions. Information provided by drill guidance systems also details the length of the tunnel, which may be helpful in cases using hamstring and bone-patella-tendon-bone grafts.
Research tool
“Navigation is helpful in research,” Colombet said. “We used it for double-bundle reconstruction and we have shown that the posterolateral bundle better controls the rotational laxity.” Colombet and his colleagues measured the laxity of 22 patients with ACL deficient knees. In 11 patients, the investigators performed an anteromedial (AM) reconstruction first followed by a double-bundle reconstruction. In the remaining patients they performed a posterolateral (PL) reconstruction first and then a double-bundle reconstruction.
At 90° flexion, they discovered that the AM bundle was more important to restrain the translation and found no significant difference when the PL reconstruction was added. However, when they performed an AM reconstruction after a PL reconstruction, they found a significant reduction in laxity. They also found that the PL bundle was the more important restraint at 20° of flexion.
An evaluation of rotation at 20° flexion revealed that the AM bundle significantly reduced internal rotation and a further reduction was seen when a PL reconstruction was added. The investigators saw similar results in the pivot shift.
“We can say that the PL bundle is more important in restraining the rotation in the pivot shift,” Colombet said.
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Image: Colombet PD |
For more information:
- Philippe D. Colombet, MD, can be reached at Centre de Chirurgie Orthopédique et Sportive, Bordeaux-Mérignac, 9 Rue Jean Moulin, 33700 Mérignac, France. +33-5-56-12-14-44; e-mail: philippe.colombet5@wanadoo.fr. He receives institutional or miscellaneous funding from and is an employee or consultant to Smith & Nephew and receives royalties from Praxim.
Reference:
- Colombet PD. Is computer navigation necessary for optimal surgical results in sports medicine? Presented as part of Symposium AA: Current trends in sports medicine: An international perspective at the American Academy of Orthopaedic Surgeons 75th Annual Meeting. March 5-9, 2008. San Francisco.