A New Method for Defining Balance

Abstract

Recently, technological advances have made it possible to quantify pounds of pressure across the bearing surface during TKA. This multicenter evaluation, using intraoperative sensors, was performed for two reasons: 1) to define "balance" 2) to determine if patients with balanced knees exhibit improved short-term clinical outcomes. Outcomes scores were compared between "balanced" and "unbalanced" patients. At 6-months, the balanced cohort scored 172.4 and 14.5 in KSS and WOMAC, respectively; the unbalanced cohort scored 145.3 and 23.8 in KSS and WOMAC (P < 0.001). Out of all confounding variables, balanced joints were the most significant contributing factor to improved postoperative outcomes (P < 0.001). Odds ratios demonstrate that balanced joints are 2.5, 1.3, and 1.8 times more likely to achieve meaningful improvement in KSS, WOMAC, and activity level, respectively.

Primary TKA Patients with Quantifiably Balanced Soft-Tissue Achieve Significant Clinical Gains Sooner than Unbalanced Patients

“…This cohort represents the contribution of eight surgeons from eight sites in the United States. All patients included in the following analysis have been previously reported in the literature [9] and have since been evaluated at the one-year followup interval.…”

“…Since the publication of early clinical data on the original 176 patients [9], 22 were lost to followup (for varying reasons unrelated to their outcomes, i.e., patient relocating and disinterest in continuing to be seen annually), 7 have yet to be seen for their 1-year clinical visit, and 12 have pending clinical visits due to a practice relocation by their respective surgeon. No revisions have been reported in this study.…”

“…The early postoperative outcomes of a prospective group of patients that have undergone sensor-assisted TKA are promising [9]. However, previously reported literature is limited to a 6-month followup window; longer followup is thereby integral to further exploring the efficacy of clinical gains after sensor-assisted TKA.…”

“…Thus, the purpose of this evaluation is to report on the disparity between the patient-reported outcomes scores of quantitatively balanced versus unbalanced patients, at 1 year, using a group of 135 multicenter patients who have been previously reported in the literature [9]. …”

Parametric analysis of electromechanical and fatigue performance of total knee replacement bearing with embedded piezoelectric transducers

“…Nowadays, in spite of comprehensive studies on the importance and significance of a balanced TKA, optimal balance is not fully quantified [3]. In fact, lack of information about in vivo force reactions, which represent the force loads experienced by the patients, preclude establishing a comprehensive correlation of intraoperative loading to postoperative loading [3, 6]. …”