Gap Balancing versus Measured Resection Technique for Total Knee Arthroplasty

Abstract

Multiple differing surgical techniques are currently utilized to perform total knee arthroplasty (TKA). We compared knee arthroplasties performed using either a measured resection or gap balancing technique to determine if either operative technique provides superior coronal plane stability as measured by assessment of the incidence and magnitude of femoral condylar lift-off. We performed 40 TKA using a measured resection technique (20 PCLretaining and 20 PCL-substituting) and 20 PCL-substituting TKA were implanted using gap balancing. All subjects were analyzed fluoroscopically while performing a deep knee bend. The incidence of coronal instability (femoral condylar lift-off) was then determined using a 3-D model fitting technique. The incidence of lift-off greater than 0.75 mm was 80% (maximum, 2.9 mm) and 70% (maximum, 2.5 mm) for the PCL-retaining and substituting TKA groups performed using measured resection versus 35% (maximum, 0.88 mm) for the gap-balanced group. Lift-off greater than 1 mm occurred in 60% and 45% of the PCL-retaining and -substituting TKA using measured resection versus none in the gap-balanced group. Rotation of the femoral component using a gap balancing technique resulted in better coronal stability which we suggest will improve functional performance and reduce polyethylene wear.

Is TKA Using Patient-specific Instruments Comparable to Conventional TKA? A Randomized Controlled Study of One System

“…Another difficulty with patient-specific guides is that they do not take into account the effects of soft tissue balancing. The gap-balancing technique has been advocated over the measured resection technique in some studies, including navigation studies, in terms of less abnormal femoral component rotation and coronal instability and better functional outcome [8,10,17,24]. We used the gravity traction method, which uses gravity as a tension force for reproducing a rectangular flexion gap.…”

“…Moreover, currently available patient-specific instruments determine femoral component rotation based on the principle of the measured resection technique without taking individual soft tissue balance into account. This is a potential limitation, as this approach may be more prone to incorrect femoral component rotation and coronal instability compared with the gap-balancing technique [8,10].…”

Patient-specific Guides Do Not Improve Accuracy in Total Knee Arthroplasty: A Prospective Randomized Controlled Trial

“…Some surgeons use tensioned gaps in addition to the measured resection to position the implants [11,12]. Postoperative malalignment is reported in a significant number of patients when these conventional instruments are used [4,14,26,35,36].…”

Measured Resection Versus Gap Balancing for Total Knee Arthroplasty

“…Therefore, the rotation and AP placement of the femoral component are used to create flexion gap symmetry (as opposed to fixed bony landmarks). Multiple comparative studies have demonstrated better femoral component rotation, coronal stability, flexion gap stability, and patellar tracking compared to measured resection techniques [3,7,9]. Sébastien Parratte MD, PhD: I agree with Dr. Springer that instability remains a significant concern with contemporary TKAs.…”

“…Research has suggested there is wide variability in femoral component rotation when using bony landmarks, which leads to asymmetry of the flexion space and condylar lift off ( Fig. 1) in flexion [3].…”