Reducing Blood Loss in Bilateral Total Knee Arthroplasty with Patient-Specific Instrumentation




Patient-specific instrumentation (PSI) in total knee arthroplasty (TKA) has been introduced to obtain consistent alignment, prevent instrumentation of the medullary canal and improve operating room efficiency. This article compares simultaneous bilateral TKA performed with and without the use of PSI in terms of surgical time; blood loss and transfusion requirements; length-of-stay, early thromboembolic events and complication rates. There was a trend to reduced total blood loss (as measured by drop in hemoglobin values) and lower transfusion rate after surgery. Further research in the form of high quality randomized trials and cost-benefit analyses may help in further consolidation of these findings.


Key points








  • The authors found a reduction in combined tourniquet time with the use of patient-specific instrumentation (PSI) in simultaneous bilateral total knee arthroplasty (TKA). Thus, PSI has the potential for better cost efficiency resulting from the reduction in surgical time in addition to the need for fewer numbers of surgical trays.



  • Avoidance of instrumentation of the intramedullary canal of the femur can theoretically decrease the blood loss during surgery. The authors found a trend to reduced total blood loss as measured by drop in hemoglobin (Hgb) values after surgery and a trend to lower transfusion rate after surgery.



  • The authors did not find any differences in the rate of thromboembolism or early complications with or without the use of PSI.



  • Length of stay was lower with the use of PSI in bilateral TKA compared with not using PSI, but it was not statistically significant.



  • Further research in the forms of high-quality randomized trials and cost-benefit analyses may help in further consolidation of these findings.






Introduction


Patient-Specific Instrumentation


The demand for primary TKA has escalated in recent times and is expected to double by 2016. Recent technological advances have, therefore, aimed at improving surgical reproducibility, efficiency, and patient outcomes. One such advancement is the development of PSI. PSI in TKA has been introduced to obtain consistent alignment, prevent instrumentation of the medullary canal, and improve operating room efficiency. A preoperative MRI or CT scan of the lower extremity is obtained, which is used by an implant manufacturer to generate a simulated version of a patient’s knee anatomy. With the help of specialized software, bony resections and component sizes are planned based on surgeon preferences and patient factors. Custom cutting guides are then fabricated, sterilized, and supplied to the surgeon’s hospital, ready for the operating room. Proposed advantages of PSI include consistency of component and limb alignment, avoidance of intramedullary instrumentation, potential for improved patient outcomes, and better cost efficiency resulting from a decrease in the number of surgical trays and reduced surgical time and operating room turnover time. Theoretically, avoidance of intramedullary instrumentation may result in reduced blood loss (and therefore transfusion requirement) as well as decreased risk of systemic embolization, which ultimately has the potential to reduce inpatient length of stay (LOS), another potential cost savings for the hospital. The added cost of imaging and fabrication of patient-specific guides is, however, a concern.


Many previous studies have compared alignment obtained with PSI and standard instrumentation, with mixed results. Fewer investigators have studied the influence of PSI on surgical time, blood loss, and LOS. Some studies have demonstrated a small but significant reduction in surgical time, whereas some studies did not. Similarly, there seems to be no consensus on whether there is truly an advantage of reduced blood loss, transfusion requirements, and LOS. No study has specifically compared surgical time, blood loss, transfusion requirements, and LOS associated with PSI in simultaneous bilateral TKA with a control group of non-PSI bilateral TKA.


Study Aims


A retrospective comparative study was performed to assess surgical time and compare early results after simultaneous bilateral TKA with and without the use of PSI, by the same surgeon and using the same implant system. The authors specifically compared 2 groups of patients evaluating (1) surgical time, (2) blood loss and transfusion requirements, (3) inpatient LOS and, lastly, (4) early thromboembolic events and complication rate.




Introduction


Patient-Specific Instrumentation


The demand for primary TKA has escalated in recent times and is expected to double by 2016. Recent technological advances have, therefore, aimed at improving surgical reproducibility, efficiency, and patient outcomes. One such advancement is the development of PSI. PSI in TKA has been introduced to obtain consistent alignment, prevent instrumentation of the medullary canal, and improve operating room efficiency. A preoperative MRI or CT scan of the lower extremity is obtained, which is used by an implant manufacturer to generate a simulated version of a patient’s knee anatomy. With the help of specialized software, bony resections and component sizes are planned based on surgeon preferences and patient factors. Custom cutting guides are then fabricated, sterilized, and supplied to the surgeon’s hospital, ready for the operating room. Proposed advantages of PSI include consistency of component and limb alignment, avoidance of intramedullary instrumentation, potential for improved patient outcomes, and better cost efficiency resulting from a decrease in the number of surgical trays and reduced surgical time and operating room turnover time. Theoretically, avoidance of intramedullary instrumentation may result in reduced blood loss (and therefore transfusion requirement) as well as decreased risk of systemic embolization, which ultimately has the potential to reduce inpatient length of stay (LOS), another potential cost savings for the hospital. The added cost of imaging and fabrication of patient-specific guides is, however, a concern.


Many previous studies have compared alignment obtained with PSI and standard instrumentation, with mixed results. Fewer investigators have studied the influence of PSI on surgical time, blood loss, and LOS. Some studies have demonstrated a small but significant reduction in surgical time, whereas some studies did not. Similarly, there seems to be no consensus on whether there is truly an advantage of reduced blood loss, transfusion requirements, and LOS. No study has specifically compared surgical time, blood loss, transfusion requirements, and LOS associated with PSI in simultaneous bilateral TKA with a control group of non-PSI bilateral TKA.


Study Aims


A retrospective comparative study was performed to assess surgical time and compare early results after simultaneous bilateral TKA with and without the use of PSI, by the same surgeon and using the same implant system. The authors specifically compared 2 groups of patients evaluating (1) surgical time, (2) blood loss and transfusion requirements, (3) inpatient LOS and, lastly, (4) early thromboembolic events and complication rate.




Methods


Institutional board approval was obtained for this study. The authors retrospectively reviewed the office charts, operating room notes, and medical records of all patients undergoing simultaneous bilateral TKAs by a single surgeon at 2 institutions from April 2011 through February 2012. Twenty-nine patients (58 TKAs) formed the study cohort. The authors included all patients undergoing simultaneous bilateral TKA during this time frame and no patients were excluded.


The senior surgeon, Dr. Cushner started using PSI for TKA in April 2011. The decision to offer PSI versus conventional instrumentation was based entirely on the surgeon’s discretion. Based on whether PSI had been used or not, 2 patient groups were formed ( Table 1 ). The non-PSI group included 14 patients (28 knees). This group comprised 8 women and 6 men, with a mean age of 59 years (Mean [SD] 6.5) and mean body mass index (BMI) of 29 (Mean [SD] 4.5). The PSI group consisted of 15 patients (30 knees) with 9 women and 6 men, having a mean age of 57 years (Mean [SD] 6.6) and mean BMI of 30 (Mean [SD] 5.1). Preoperative diagnosis was osteoarthritis in all knees.



Table 1

Patient groups
















PSI Non-PSI
15 Patients/30 knees 14 Patients/28 knees
6 Men/9 women, mean age 57 y (Mean [SD] 4.5) 6 Men/8 women, mean age 59 y (Mean [SD] 6.5)
Legion (Smith & Nephew) TKA with Visionaire Legion (Smith & Nephew) TKA with standard instrumentation and OrthAlign for tibial cut


All patients received a similar design of posterior-stabilized cemented TKA by the same manufacturer. All surgeries were performed using either the Legion or Journey II posterior-stabilized TKA standard instrumentation with OrthAlign for tibial cut in non-PSI group system (Smith & Nephew, Memphis, Tennessee) and the Visionaire (Smith & Nephew) PSI was used in PSI group. The latter is an MRI-based PSI system, which, in addition to the MRI, uses long-leg radiographs for preoperative planning.


Patients donated 2 units of autologous blood and were given 3 erythropoetin injections (40,000 IU each) (Procrit, Centocor Ortho Biotech, Horsham, Pennsylvania), 3 weeks, 2 weeks, and 1 week prior to surgery. All patients received oral sustained-release oxycodone (20 mg) (OxyContin, Purdue Pharma, Stamford, Connecticut) and celecoxib (200 mg) (Celebrex, Pfizer, New York, New York) preemptively.


Spinal anesthesia was given to all patients followed by bilateral femoral nerve blocks. A pneumatic tourniquet set to 300 mm Hg to 350 mm Hg (based on body habitus) was used in all cases and was inflated prior to skin incision and deflated after skin closure and application of compression dressing.


A medial parapatellar arthrotomy was used for exposure. In the non-PSI group, a handheld accelerometer-based surgical navigation system (KneeAlign, OrthAlign, Aliso Viejo, California) was used to make the tibial resection first, followed by distal femoral resection using a conventional intramedullary alignment rod. The handheld navigation was not used for femoral resection. The remaining femoral cuts were performed after setting the femoral rotation based on the transepicondylar axis and Whiteside line. The femoral canal was capped in all non-PSI cases with a bone plug made from resected bone. In the PSI group, all femoral cuts were performed first as recommended by the manufacturer and tibial resection was performed last using the fabricated guides. Osteophyte removal and soft tissue releases were performed to balance flexion-extension gaps. Patella resurfacing was performed in all knees. Closure was performed over a deep reinfusion drain, which was clamped for the first 4 hours and removed on postoperative day (POD) 1. Blood was reinfused if the output was more than 100 mL in the first 6 hours after unclamping of drains. Closure was performed using knotless barbed sutures (Quill Self-Retaining System, Angiotech Pharmaceuticals, Vancouver, British Columbia, Canada), using #2 for closure of the arthrotomy, #0 for the subcutaneous layer, and #2-0 for subcuticular closure.


A sterile compression dressing was then applied and compression maintained for 24 hours. Cryotherapy was initiated. Postoperatively, patients received short- and long-acting oral oxycodone, acetaminophen, and celecoxib, with intravenous morphine as needed. Patients were encouraged to get out of bed on POD1 and active and passive knee range-of-motion exercises were initiated. Subcutaneous enoxaparin injections were used for thromboembolism prophylaxis starting 18 to 24 hours after surgery and continued for 2 weeks postoperatively. The criteria for blood transfusion were standardized and included either presence of signs or symptoms of anemia or hypovolemia unresponsive to fluid resuscitation or Hgb concentration less than 7.5 g/dL. Complete blood cell count was performed daily for the first 3 days of inpatient stay and then as needed. Physical therapy was provided daily, starting POD1. Patients were allowed full weight bearing with a walker frame. According to the prespecified home discharge criteria set forth by the 2 hospitals, patients were allowed to go home if they were able to walk 150 feet (46 m), independently transfer from a bed and chair, and go up and down a flight of stairs. Patients were discharged to a skilled nursing facility if they failed to meet the discharge to home criteria. Social work was consulted on POD1 to facilitate eventual discharge.


Tourniquet time was evaluated as a measure of the length of the surgical procedure. Tourniquet time was added for the 2 sides to generate the total tourniquet time. The reduction in Hgb concentration was used as a measure of blood loss and was calculated based on serial postoperative Hgb levels using preoperative Hgb (obtained just prior to surgery) as baseline. Blood transfusion rates were analyzed and compared between groups. Inpatient LOS was assessed in days with the day after surgery counted as the first day and the day of discharge counted as the last day. All thromboembolic episodes were noted up to 3 months postoperatively. Similarly, all early reoperations and complications were noted.


Data were analyzed to determine if there was a significant difference between the 2 groups in demographics, preoperative and postoperative Hgb values, maximum Hgb reduction, average number of allogeneic units transfused in the 2 groups, tourniquet time, LOS, and disposition. Independent t tests were used for comparing continuous data and chi-square test (with Fisher exact test) for comparing categorical data. The level of statistical significance was set at P = .05. Statistical analyses were performed using SPSS, Version 16, software (Chicago, Illinois).

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Oct 6, 2017 | Posted by in ORTHOPEDIC | Comments Off on Reducing Blood Loss in Bilateral Total Knee Arthroplasty with Patient-Specific Instrumentation

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