A new method to measure ligament balancing in total knee arthroplasty: laxity measurements in 100 knees

Abstract

BackgroundLigament balancing is considered a prerequisite for good function and survival in total knee arthroplasty (TKA). However, there is no consensus on how to measure ligament balance intra-operatively and the degree of stability obtained after different balancing techniques is not clarified.PurposeThis study presents a new method to measure ligament balancing in TKA and reports on the results of a try-out of this method and its inter-observer reliability.MethodsAfter the implantation of the prosthesis, spatulas of different thickness were used to measure medial and lateral condylar lift-off in flexion and extension in 70 ligament-balanced knees and in 30 knees were ligament balancing was considered unnecessary. Inter-observer reliability for the new method was estimated and the degree of medial–lateral symmetry in extension and in flexion, and the equality of the extension gaps and flexion gaps were calculated.ResultsThe method was feasible in all operated knees, and found to be very reliable (intraclass correlation coefficient = 0.88). We found no statistically significant difference in condylar lift-off between the ligament-balanced and the non ligament-balanced group, however, there was a tendency to more outliers in flexion in the ligament-balanced group.ConclusionsOur method for measuring ligament balance is reliable and provides valuable information in assessing laxity intra-operatively. This method may be a useful tool in further research on the relationship between ligament balance, function and survival of TKA.

Simulation of total knee arthroplasty in 5° or 7° valgus: A study of gap imbalances and changes in limb and knee alignments from native

“…The results of our simulation are consistent with clinical practice of TKA in which soft tissue release is performed routinely to establish rectangular gaps in extension and flexion. For example, soft tissue release was performed in 70% of patients when the knee was set in the range of 5°–8° valgus, in 76% of patients with varus knees when the knee was set in 5° valgus, in at least 50% of patients depending on the deformity (i.e., varus or valgus) using the gap‐balancing method, and in the majority of patients using the gap‐balancing method . These percentages are in general agreement with those of Table .…”

Radiological outcomes of pinless navigation in total knee arthroplasty: a randomized controlled trial

“…These topics have to be addressed using surgical techniques described by Ranawat et al [24], Fitz et al [12] or Aunan et al [1]. Likewise, implant sizing cannot be targeted with this pinless express workflow.…”

Highly Satisfied Total Knee Arthroplasty Patients Display a Wide Range of Soft Tissue Balance

“…23 In another study demonstrating the importance of consistent medial ligament balance Aunan et al, using manual assessment of laxity, documented better outcomes with 2 and 3 mm of medial extension and flexion laxity, respectively, post TKA. 11 We found a small mean alteration in the laxity of the medial ligament in our subjects through range and this is likely to have significantly contributed to the high degree of satisfaction in our subject group. In our subjects, we documented a mean increase in medial laxity between maximum extension and 90 degrees of flexion of 0.4 degrees þ/ À 1.3 (range, À2.5 to 4.5 degrees) with an even smaller mean increase between 20 and 90 degrees of 0.1 degrees þ/À 1.5 (range, À3.5 to 3.0 degrees).…”

“…Aunan et al linked residual medial laxity post prosthesis implantation of no more than 2 mm in extension and 3 mm in flexion to improved functional outcomes in cruciate retaining TKA. 11,12 Differing prostheses (posterior stabilized [PS], cruciate retaining [CR], rotating platform-cruciate retaining and substituting TKA), were utilized across the studies that made these laxity recommendations. [6][7][8][9]11,12 Only one study to date has specifically studied PS TKA in terms of optimal coronal plane laxity.…”