Total knee arthroplasty (TKA) is a reliable and successful treatment for end-stage degenerative joint disease of the knee. Given the reproducibility of its generally excellent outcomes, TKA is increasingly being performed.1 However, the potential complications of this procedure can be devastating.2-4 The arthroplasty literature has shed light on the detrimental effects of postoperative blood loss and anemia.5,6 In addition, the increase in transfusion burden among patients is not without risk.7 Given these concerns, surgeons have been tasked with determining the ideal methods for minimizing blood transfusions and postoperative hematomas and anemia. Several strategies have been described.8-11 Hemostasis can be achieved with use of intravenous medications, intra-articular agents, or electrocautery devices. Electrocautery technologies include traditional electrocautery (TE), saline-coupled bipolar sealer (BS), and argon beam coagulation (ABC). There is controversy as to whether outcomes are better with one hemostasis method over another and whether these methods are worth the additional cost.
In traditional (Bovie) electrocautery, a unipolar device delivers an electrical current to tissues through a pencil-like instrument. Intraoperative tissue temperatures can exceed 400°C.12 In BS, radiofrequency energy is delivered through a saline medium, which increases the contact area, acts as an electrode, and maintains a cooler environment during electrocautery. Proposed advantages are reduced tissue destruction and absence of smoke.12 There is evidence both for10,12-16 and against17-20 use of BS in total joint arthroplasty. ABC, a novel hemostasis method, has been studied in the context of orthopedics21,22 but not TKA specifically. ABC establishes a monopolar electric circuit between a handheld device and the target tissues by channeling electrons through ionized argon gas. Hemostasis is achieved through thermal coagulation. Tissue penetration can be adjusted by changing power, probe-to-target distance, and duration of use.23 We conducted a study to assess the efficacy of all 3 electrocautery methods during TKA. We hypothesized the 3 methods would be clinically equivalent with respect to estimated blood loss (EBL), 48-hour wound drainage, operative time, and change from preoperative hemoglobin (Hb) level.
Methods
We conducted a retrospective cohort study of consecutive primary TKAs performed by Dr. Levine between October 2010 and November 2011. Patients were identified by querying an internal database. Exclusion criteria were prior ipsilateral open knee procedure, prior fracture, nonuse of our standard hemostatic protocol, and either tourniquet time under 40 minutes or intraoperative documentation of tourniquet failure. As only 9 patients were initially identified for the TE cohort, the same database was used to add 32 patients treated between April 2009 and October 2009 (before our institution began using BS and ABC).
Clinical charts were reviewed, and baseline demographics (age, body mass index [BMI], preoperative Hb level) were abstracted, as were outcome metrics (EBL, 48-hour wound drainage, operative time, postoperative transfusions, adverse events (AEs) before discharge, and change in Hb level from before surgery to after surgery, in recovery room and on discharge). Statistical analyses were performed with JMP Version 10.0.0 (SAS Institute). Given the hypothesis that the 3 hemostasis methods would be clinically equivalent, 2 one-sided tests (TOSTs) of equivalence were performed with an α of 0.05. With TOST, the traditional null and alternative hypotheses are reversed; thus, P < .05 identifies statistical equivalence. The advantage of this study design is that equivalence can be identified, whereas traditional study designs can identify only a lack of statistical difference.24 We used our consensus opinions to set clinical insignificance thresholds for EBL (150 mL), wound drainage (150 mL), decrease from postoperative Hb level (1 g/dL), and operative time (10 minutes). Patients who received a blood transfusion were subsequently excluded from analysis in order to avoid skewing Hb-level depreciation calculations. Analysis of variance (ANOVA) and χ2 tests were used to compare preoperative variables, transfusion requirements, hospital length of stay, and AE rates by hemostasis type.
Cautery Technique
In all cases, TE was used for surgical dissection, which followed a standard midvastus approach. Then, for meniscal excision, the capsule and meniscal attachment sites were treated with TE, BS, or ABC. During cement hardening, an available supplemental cautery option was used to achieve hemostasis of the suprapatellar fat pad and visible meniscal attachment sites. All other aspects of the procedure and the postoperative protocols—including the anticoagulation and rapid rehabilitation (early ambulation and therapy) protocols—were similar for all patients. The standard anticoagulation protocol was to use low-molecular-weight heparin, unless contraindicated. Tranexamic acid was not used at our institution during the study period.
Results
For the study period, 280 cases (41 TE, 203 BS, 36 ABC) met the inclusion criteria. Of the 280 TKAs, 261 (93.21%) were performed for degenerative arthritis. There was no statistically significant difference among cohorts in indication (χ2 = 1.841, P = .398) or sex (χ2 = 1.176, P= .555).