Robotic-Assisted Total Knee Arthroplasty: What are Patients' Perspectives, Understanding and Expectations?

BACKGROUND: The rate of using robotic-assisted total knee arthroplasty (RA-TKA) has increased markedly. Understanding how patients view the role of robotics during total knee arthroplasty (TKA) informs shared decision making and facilitate efforts to appropriately educate patients regarding the risks and benefits of robotic assistance. METHODS: A self-administered questionnaire was completed by 440 potential TKA patients at the time of their surgery scheduling. Participants answered 25 questions regarding RA-TKA, socioeconomic factors, and their willingness to pay (WTP) for RA-TKA. Logistic regressions were used to determine if population characteristics and surgeon preferences influenced the patients' perceptions of RA-TKA. RESULTS: There were 39.7% of respondents who said that they had no knowledge regarding RA-TKA. Only 40.7% of participants had expressed a desire for RA-TKA to be used. There were 8.7% who were WTP extra for the use of RA-TKA. Participants believed that the main 3 benefits of RA-TKA compared to conventional methods were: more accurate implant placement (56.2%); better results (49.0%); and faster recovery (32.1%). The main 3 patient concerns were harm from malfunction (55.2%), reduced surgeon role in the procedure (48.1%), and lack of supportive research (28.3%). Surgeon preference of RA-TKA was associated with patient's willingness to have RA-TKA (odds ratio 4.60, confidence interval 2.98-7.81, P < .001), and with WTP extra for RA-TKA (odds ratio 2.05, confidence interval: 1.01-4.26, P = .049). CONCLUSION: Patient knowledge regarding RA-TKA is limited. Nonpeer-reviewed online information may make prospective TKA candidates vulnerable to misinformation and aggressive advertising. The challenge for orthopaedic surgeons is to re-establish control and reliably educate patients about the proven advantages and disadvantages of this emerging technology.

The Frequency, Reasoning, and Impact of Repeated Radiographs at the Initial Orthopedic Arthroplasty Visit.

BACKGROUND: Patients presenting to an orthopedic clinic with joint pain often seek prior care and imaging before consultation. It is unknown how often orthopedic surgeons must repeat imaging and whether repeat imaging has an impact on diagnosis or management. The purpose of this study was to determine the frequency, reason, and impact of repeating radiographs in outpatient orthopedic clinics. METHODS: Patients ≥18 years of age presenting with hip and/or knee pain were prospectively enrolled at five arthroplasty clinics from January 2019 until June 2020. Before the initial visit, surveys were distributed to patients regarding the reason for their visit, prior care, and prior diagnostic imaging. At the conclusion of the visit, surgeons reported if repeat radiographs were obtained, and if so, surgeons documented the views ordered, the reasoning for new films, and if diagnosis or management changed as a result. Patients were grouped based on repeat imaging status, and of those with repeat imaging, subgroup analysis compared patients based on if management changed. RESULTS: Of 292 patients, 256 (88%) had radiographs before their office visit, and 167 (65%) obtained repeat radiographs. Radiographs were most commonly repeated if they were inaccessible (47%), followed by if they were non-weight-bearing (40%). Repeated radiographs changed the diagnosis in 40% of patients and changed management in 22% of patients. CONCLUSION: Most patients underwent repeat radiography at their orthopedic visit. The primary reasons were owing to accessibility or the patient being non-weight-bearing. Repeat radiographs changed management in almost one-quarter of patients.

Dual Mobility and Conventional Bearings Have Comparably Low Dislocation Rates for Anterior-Based Approaches in Total Hip Arthroplasty.

BACKGROUND: Dual mobility (DM) bearings for total hip arthroplasty (THA) have been proposed to reduce the risk of instability in select patients, especially those undergoing revision surgery. The use of DM bearings has not been studied as extensively for use in primary THA. The purpose of this study is to compare outcomes following primary THA with anterior-based approaches between patients receiving DM bearings vs standard bearing hip implants. METHODS: We retrospectively reviewed a consecutive series of patients undergoing primary THA through an anterior-based approach. A 3:1 propensity score match was performed between the standard and DM bearing patients to control for possible risk factors for instability. Functional outcomes, dislocations, and aseptic revisions were identified for each patient. The effect of DM on postoperative outcomes was determined using univariate statistical analyses. RESULTS: In total, 250 DM bearings were compared to 753 standard bearings. We found no difference in dislocation rate between single bearings and DM bearings (0.53% vs 0.4%). There was 1 DM dislocation occurring in a liner with outer diameter of 38 mm. There were no DM dislocations with outer diameter >38 mm. Aseptic revision surgery was more common in DM. This difference was driven by higher incidence of femoral periprosthetic fracture. There were no differences in functional outcomes. CONCLUSION: Dislocation rates are comparably low between DM bearings and standard bearings for THA done using an anterior approach to the hip. Further investigation is needed to determine if specific patient populations may benefit from DM implants for primary THA when an anterior approach to the hip is being used.

Survivorship, Clinical and Radiographic Outcomes of a Novel Cementless Metal-Backed Patella Design.

BACKGROUND: Enhanced implant longevity through biological fixation is achievable using cementless total knee arthroplasty but concerns about patellar component failure have lingered because of prior experiences with older component designs. A new metal-backed patella (MBP) design was released which features a 3-dimensional printed porous titanium metal backing to improve biologic fixation potential and a unique compression molding technique to create a stronger interlock layer between the polyethylene and metal backing. Our study purpose was to determine the clinical and radiographic outcomes and survivorship of this novel cementless MBP. METHODS: Our institutional registry identified 388 cementless MBP with minimum 2-year and 80 with minimum 5-year follow-up. Knee Injury and Osteoarthritis Outcome Score for Joint Replacement and 12-item Veterans RAND/Short Form Health Survey (VR/SF-12) scores were used to evaluate clinical outcomes. Aseptic loosening noted on radiographs as well as revision for any reason were the end points used to determine survivorship. RESULTS: Improvement in the preoperative Knee Injury and Osteoarthritis Outcome Score for Joint Replacement, VR/SF-12 physical health and mental health scores were all statistically significant at 2-year follow-up and the VR/SF-12 mental health score at 5-year follow-up. By radiologic criteria, biologic fixation of the patellar component was present in all except 1 case at 2 years (99.6%) and at 5 years (97.7%). Radiolucent lines were present in 15 cases (6.2%) at 2 years and in 6 cases (14%) at 5 years, but progressive increase in radiolucent lines was seen in only 4 cases. No component was revised for loosening; aseptic survivorship was 100%. CONCLUSION: This 3-dimensional printed cementless patellar component shows excellent survivorship at 2-year and 5-year follow-up. We are hopeful about the long-term durability of this implant.

Decreased flexion contracture after total knee arthroplasty using Botulinum toxin A: a randomized controlled trial.

PURPOSE: Flexion contracture after total knee arthroplasty (TKA) can cause significant dissatisfaction. Botulinum toxin A has shown improved extension in patients with spastic flexion contractures after TKA. The purpose of this study was to evaluate whether Botulinum toxin A improves knee extension for any patient with flexion contractures following TKA. METHODS: A prospective, double-blinded, randomized controlled trial was conducted. Fourteen patients (15 knees), with a flexion contracture (≥10°) one month postoperatively, were randomized to receive either Botulinum toxin A or saline placebo to the affected hamstrings. The subject, surgeon, and administering physiatrist were blinded to the treatment group throughout the study. Subject range of motion (ROM) was evaluated at 1, 6, and 12 months following injection. Differences were tested using mixed-effects regression to control for multiple measurements. RESULTS: The initial post-operative flexion contracture averaged 19° ± 6° in the Botulinum toxin A group and 13° ± 3° in the saline group. Injections were performed 53 and 57 days after TKA in the Botulinum toxin A and saline groups, respectively. Post-injection extension improved to an average of 8, 5, and 1 degrees for BTX and 4, 2, and 1 degrees for SAL, at 1, 6, and 12 months, respectively, compared to pre-injection extension (p < 0.0001). Improvement in knee extension at 1 year improved 18° ± 7.5° for Botulinum toxin A and 12° ± 2° for saline (p = 0.04). No complications resulted from either injection. CONCLUSION: Patients who received Botulinum toxin A or placebo were able to achieve near full extension one year after surgery. There was a statistically significant improvement in the amount of extension achieved at 1 year with Botulinum toxin A, but this may be of little clinical significance. Since achieving full extension is important for patient function and satisfaction, novel techniques to address this issue deserve special attention. LEVEL OF EVIDENCE: I.

The Effect of Implementing a Multimodal Approach on the Rates of Periprosthetic Joint Infection After Total Joint Arthroplasty.

INTRODUCTION: We examined the efficacy of implementing a multimodal program aimed at reducing the incidence of periprosthetic joint infection (PJI) after total joint arthroplasty (TJA) in a mid-size community hospital. METHODS: An infection reduction committee (IRC) was formed at our hospital in November 2010. The IRC consisted of two orthopaedic surgeons, an infectious disease specialist, an internist with extensive experience in perioperative medical management of TJA patients, an anesthesiologist, the hospital infection control nurse, and two additional nurses. Their goals were to 1) evaluate the current incidence of PJI at our institution, compare it with the reported national data, and consider measures already in place directed at preventing PJI; 2) review and routinely evaluate recently published studies or information obtained from continuing medical education events related to PJI to determine if practice changes were warranted (based on intervention efficacy, cost, and safety) and then develop a plan to implement appropriate alterations in perioperative protocols using a multimodal strategy; and 3) evaluate the effect and safety of newly-introduced infection reduction strategies on the incidence of PJI. RESULTS: In 2008, the incidence of PJI at our hospital was 1.0%. By 2013, this rate had reduced to 0.4%. In absolute numbers, in 2009, 20 of 1,150 TJAs developed a PJI in the 12-month period following partial, primary, or revision TJA. In 2013, PJI occurred in only 4 of 1,053 TJA patients. CONCLUSION: We found that formation of an IRC focused on evaluating and implementing strategies to reduce PJI following TJA can be effective.

Aspirin Can Be Used as Prophylaxis for Prevention of Venous Thromboembolism After Revision Hip and Knee Arthroplasty.

BACKGROUND: The optimal prophylaxis for prevention of venous thromboembolic events (VTEs) after revision total joint arthroplasty (TJA) remains unknown. The objective of this study was to evaluate whether aspirin, known to be effective for prevention of VTEs after primary arthroplasty, is also effective after revision TJA. METHODS: We studied 2997 consecutive patients who underwent revision TJA between 2005 and 2013 and were treated with intermittent pneumatic compression devices and either aspirin (534 patients) or warfarin (2463 patients) for VTE prophylaxis. Pertinent data including the incidence of symptomatic VTEs, bleeding events, infection, and mortality were retrieved from our prospectively collected database. RESULTS: The incidence of symptomatic VTEs was significantly higher in the warfarin group at 1.75% (43 of 2463) compared with 0.56% (3 of 534) in the aspirin group (odds ratio: 3.2; 95% CI: 1.03-16.3; P = .03). There was a higher rate of bleeding events with administration of warfarin (1.5%) compared with aspirin (0.4%; P = .02; odds ratio: 4.1; 95% CI: 1.2-34.0). The rate of surgical site infection was similar between the aspirin group and the warfarin group (1.61% and 1.70%, respectively). CONCLUSION: Administration of aspirin as prophylaxis against VTEs after revision arthroplasty may be a viable option as it appears to be more effective than warfarin in prevention of symptomatic VTEs and is associated with a lower rate of complications.

Are Preoperative Serologic Type and Screen Tests Necessary for Primary Total Joint Arthroplasty Patients in Specialty Surgical Hospitals?

BACKGROUND: Blood loss during total joint arthroplasty (TJA) has been a major concern requiring routine preoperative patient type and screen (T&S); however, with the implementation of blood conserving therapy, a marked decrease for perioperative transfusions has been observed. Many TJAs are now being performed in T&S mandated specialty surgical hospitals (SSHs) that lack on-site blood banks; therefore, the purpose of our study was to determine whether T&S (1) is necessary in SSH for TJA patients and (2) identifies patient risk factors associated with perioperative blood transfusion in SSH. METHODS: A retrospective study was conducted on 1034 consecutive primary TJAs performed between 2013 and 2014 at a 12-bed SSH who all received T&S. Patients were matched (1:1) to 964 inpatient TJA patients performed at a university hospital without routine T&S. Data on surgery type, patient demographics, hemoglobin and hematocrit results, and transfusion rates were collected. Multivariate logistic regression identified perioperative transfusion risk factors. RESULTS: Overall transfusion rates for the matched SSH (1.8% [17/964]) and university hospital populations (2.9% [28/964]) were similar (P = .13), with no emergent transfusions. SSH transfusion rates for simultaneous bilateral THA, simultaneous bilateral TKA, unilateral THA, and unilateral TKA were 21.1% (4/19), 3.1% (4/128), 2.7% (12/439), and 0.0% (0/448), respectively. Multivariate logistic regression identified unilateral THA (P ≤ .001), simultaneous bilateral TJA (P = .001), age (P = .05), and abnormal preoperative hemoglobin (P = .02) as significant transfusion risk factors at SSH. CONCLUSION: Due to low transfusion rates and lack of emergency transfusions, we recommend routinely ordering T&S for bilateral THA but not for unilateral TJA patients, at SSHs.

Performance characteristics of broth-only cultures after revision total joint arthroplasty.

BACKGROUND: Surgeons frequently obtain intraoperative cultures at the time of revision total joint arthroplasty. The use of broth or liquid medium before applying the sample to the agar medium may be associated with contamination and false-positive cultures; however, the degree to which this is the case is not known. QUESTIONS/PURPOSES: We (1) calculated the performance characteristics of broth-only cultures (sensitivity, specificity, positive predictive value, and negative predictive value) and (2) characterized the organisms identified in broth to determine whether a specific organism showed increased proclivity for true-positive periprosthetic joint infection (PJI). METHODS: A single-institution retrospective chart review was performed on 257 revision total joint arthroplasties from 2009 through 2010. One hundred ninety (74%) had cultures for review. All culture results, as well as treatment, if any, were documented and patients were followed for a minimum of 1 year for evidence of PJI. Cultures were measured as either positive from the broth only or broth negative. The true diagnosis of infection was determined by the Musculoskeletal Infection Society criteria during the preoperative workup or postoperatively at 1 year for purposes of calculating the performance characteristics of the broth-only culture. RESULTS: The sensitivity, specificity, positive predictive value, and negative predictive value were 19%, 88%, 13%, and 92%, respectively. The most common organism identified was coagulase-negative Staphylococcus (16 of 24 cases, 67%). Coagulase-negative Staphylococcus was present in all three true-positive cases; however, it was also found in 13 of the false-positive cases. CONCLUSIONS: The broth-only positive cultures showed poor sensitivity and positive predictive value but good specificity and negative predictive value. The good specificity indicates that it can help to rule in the presence of PJI; however, the poor sensitivity makes broth-only culture an unreliable screening test. We recommend that broth-only culture results be carefully scrutinized and decisions on the diagnosis and treatment of infection should be based specifically on the Musculoskeletal Infection Society criteria. LEVEL OF EVIDENCE: Level IV, diagnostic study. See Instructions for Authors for a complete description of levels of evidence.

Aquacel surgical dressing reduces the rate of acute PJI following total joint arthroplasty: a case-control study.

An effort to prevent PJI has led to the development of antimicrobial dressings that support wound healing. We sought to determine whether Aquacel Surgical dressing independently reduces the rate of acute PJI following TJA. A single institution retrospective chart review of 903 consecutive cases who received the Aquacel Surgical dressing and 875 consecutive cases who received standard gauze dressing was conducted to determine the incidence of acute PJI (within 3 months). The incidence of acute PJI is 0.44% in the Aquacel dressing group compared to 1.7% in the standard gauze dressing group (P = 0.005). Multivariate analysis revealed that use of Aquacel dressing was an independent risk factor for reduction of PJI (odds ratio of 0.165, 95% confidence interval: 0.051-0.533). Aquacel Surgical dressing significantly reduces the incidence of acute PJI.

The effect of laminar air flow and door openings on operating room contamination.

We evaluate the association of laminar airflow (LAF) and OR traffic with intraoperative contamination rates. Two sterile basins were placed in each room during 81 cases, one inside and one outside the LAF. One Replicate Organism Detection and Counting (RODAC) plate from each basin was sent for culture at successive 30-minute intervals from incision time until wound closure. At successive 30-minute intervals more plates were contaminated outside than inside the LAF. A negative binomial model showed that the bacteria colony forming units (CFU) depended on whether there were any door openings (P=0.02) and the presence of LAF (P=0.003). LAF decreases CFU by 36.6%. LAF independently reduces the risk of contamination and microbial counts for surgeries lasting 90 minutes or less.

Local Anesthesia Approach for Percutaneous Screw Fixation of an Impacted Subcapital Femoral Neck Fracture: A Technique for High-Risk Patients.

Elderly, frail patients and those who have substantial medical co-morbidities who sustain hip fractures present a challenging problem for treatment as they are at very high risk for complications from surgical intervention. The functional outcomes, pain levels, and mortality rates all worsen when non-surgical treatment is used. The safety of administering general or spinal anesthesia may be a concern in certain cases. Other modalities, such as epidural or caudal anesthesia, may be an option; however, the use of local anesthesia may be advantageous for patients with non-displaced and impacted femoral neck fractures undergoing surgical intervention. We present a case report describing the successful treatment of an elderly male who had relative contraindications to spinal anesthesia and high risk for general anesthesia and was successfully treated with percutaneous screw fixation of a femoral neck fracture using local anesthesia with a light, monitored anesthetic.

Fracture of a Metal-Backed Ceramic Liner After Total Hip Arthroplasty: A Case Report.

Total hip arthroplasty (THA) is a common procedure that has become increasingly prevalent in a younger patient population. With improvements in prostheses and materials, the survivorship of implants has increased. Historically, the excellent wear characteristics of ceramic-on-ceramic (CoC) implants made them an appealing choice compared to other bearing options. Yet, the potential benefits of the bearing longevity related to the wear characteristics have been combated by their unique causes of failure such as implant fracture and squeaking. Metal-backed ceramic liners were developed to minimize impingement-related chipping at the periphery of the implant that may propagate to catastrophic implant fracture. We report a case involving a fracture of a metal-backed ceramic liner that presented with months of pain and crepitus with no overt signs of fracture on imaging.

The Complication of a Retained Broken Distal Interlocking Screw Within a Cephalomedullary Nail During Conversion Hip Arthroplasty: A Case Report.

In patients who undergo femoral fracture fixation with a cephalomedullary nail, the breakage of one or more of the distal interlocking screws is a well-described phenomenon. The presence of a broken interlocking screw in patients who require the removal of their cephalomedullary nail presents a unique challenge. The broken interlocking screw may be retrieved, or the screw may be retained if it is not engaged within the nail and the nail can safely be removed while leaving the broken screw fragment behind. We report a hip conversion arthroplasty case with a broken interlocking screw where the nail was removed with ease and the broken screw was assumed to have been left behind. Cerclage wires were placed for an apparent proximal femoral fracture. Postoperative X-rays demonstrated a large lucency tracking from the prior location of the distal interlocking screw to the calcar region. This finding made it evident that the broken screw had been retained in the nail and was dragged up the femur upon nail removal, causing a large gouge spanning the entire femur.

Is it time to include vancomycin for routine perioperative antibiotic prophylaxis in total joint arthroplasty patients?

In an effort to reduce methicillin-resistant Staphylococcus aureus (MRSA) and overall periprosthetic joint infections (PJI), we switched the perioperative prophylactic antibiotic during total knee arthroplasty and total hip arthroplasty from cefazolin to vancomycin in June 2008. We retrospectively reviewed the total and MRSA PJI in 5036 primary total joint arthroplasties, as well as the cure rate of PJI from January 2006 to June 2008 (Ancef Period) and June 2008 to December 2010 (Vanco Period). With vancomycin, total PJI was significantly reduced (1.0%-0.5%) and MRSA PJI (0.23%-0.07%). Periprosthetic joint infections that occurred were more successfully treated with irrigation and debridement only, not requiring spacer (76.9% vs 22.2%). The use of vancomycin as the perioperative prophylactic antibiotic for primary total joint arthroplasties appeared to be effective in decreasing the rate of PJI and may result, when they occur, in infections with less virulent organisms.

Save the Greater Trochanter: A Novel Modification to the Extended Trochanteric Osteotomy.

The extended trochanteric osteotomy is the workhorse for removal of well-fixed femoral stems during total hip revision arthroplasty. Despite its reliable performance in exposing the implants for removal and accessing the femoral canal, significant complications can occur. Though these complications are rare, trochanteric nonunion, trochanteric escape, and femoral implant subsidence can have a significant negative impact on gait mechanics and patient outcome. If access to the canal was still possible and the greater trochanter could remain in place, these complications could be minimized or possibly even eliminated. This paper describes a novel technique using a lateral cortical window just distal to the greater trochanter that allows removal of a well-fixed stem and leaves the greater trochanter intact.

Delayed surgery for patients with femur and hip fractures-risk of deep venous thrombosis.

BACKGROUND: This prospective study explores the incidence of preoperative deep venous thrombosis (DVT) in a group of patients with hip and femur fracture who for various reasons experienced a delay of >24 hours from the time of injury until time of surgery. We also evaluated the results of preoperative treatment with inferior vena cava (IVC) filter. METHODS: There were 101 consecutive patients with a mean age of 75.8 years. The mean time to surgery from injury was 3.5 days. All patients were evaluated for signs and symptoms of DVT and underwent Doppler ultrasound before surgery. All patients received preoperative prophylactic anticoagulation. Those patients with DVT underwent IVC filter insertion before surgical intervention. RESULTS: No patient exhibited signs or symptoms of DVT; however, preoperative ultrasound detected DVT in 10 patients. Despite negative ultrasound, two additional patients developed pulmonary embolus preoperatively for an overall incidence of thromboembolic disease of 11.9%. The average delay in surgery was 5.7 days for patients with DVT versus 3.2 days for those without (p = 0.021). The incidence increased each day from 14.5% if surgery was delayed >1 day to 33.3% if surgery was delayed >7 days. Relative risk increased from 2.32 to 3.71 over the same period. There were no postoperative thromboembolic complications or complications related to IVC filter placement in these patients. DISCUSSION: In this prospective study, we observed that patients experiencing a delay in surgical care for an acute hip or femur fracture are at a relatively high risk for development of thromboembolic disease despite prophylactic anticoagulation. There was a direct correlation between the period of delay and the incidence of thromboembolism. Clinical examination in this setting is unreliable as none of these patients had signs or symptoms suggestive of DVT. We suggest that all patients with delayed (>24 hours) surgical intervention undergo preoperative Doppler ultrasound to rule out DVT. Appropriate measures such as placement of an IVC filter and aggressive postoperative anticoagulation should then be implemented for those with DVT and/or pulmonary embolus.

Excellent mid-term follow-up for a new 3D-printed cementless total knee arthroplasty.

AIMS: Cementless total knee arthroplasty (TKA) offers the potential for strong biological fixation compared with cemented TKA where fixation is achieved by the mechanical integration of the cement. Few mid-term results are available for newer cementless TKA designs, which have used additive manufacturing (3D printing). The aim of this study was to present mid-term clinical outcomes and implant survivorship of the cementless Stryker Triathlon Tritanium TKA. METHODS: This was a single institution registry review of prospectively gathered data from 341 cementless Triathlon Tritanium TKAs at four to 6.8 years follow-up. Outcomes were determined by comparing pre- and postoperative Knee Injury and Osteoarthritis Outcome Score for Joint Replacement (KOOS JR) scores, and pre- and postoperative 12-item Veterans RAND/Short Form Health Survey (VR/SF-12) scores. Aseptic loosening and revision for any reason were the endpoints which were used to determine survivorship at five years. RESULTS: At mid-term follow-up, the mean KOOS JR score improved significantly from 33.14 (0 t0 85, standard deviation (SD) 21.88) preoperatively to 84.12 (15.94 to 100, SD 20.51) postoperatively (p < 0.001), the mean VR/SF-12 scores improved significantly from physical health (PH), 31.21 (SD 5.32; 23.99 to 56.77) preoperatively to 42.62 (SD 10.72; 19.38 to 56.82) postoperatively (p < 0.001) and the mental health (MH), 38.15 (SD 8.17; 19.06 to 60.75) preoperatively to 55.09 (SD 9.64; 19.06 to 66.98) postoperatively (p < 0.001). A total of 11 revisions were undertaken, with an overall revision rate of 2.94%, including five for periprosthetic joint infection (1.34%), three for loosening (0.80%), two for instability (0.53%), and one for pain (0.27%). The overall survivorship was 97.06% and survivorship for aseptic loosening as the endpoint was 98.40%, with a 99.5% survivorship of the 3D-printed tibial component. CONCLUSION: This 3D-printed cementless total knee system shows excellent survivorship at mid-term follow-up. This design and the ability to obtain cementless fixation offers promise for excellent long-term durability. Cite this article: Bone Joint J 2021;103-B(6 Supple A):32-37.

After Incision, the Skin Knife Blade Is No More Contaminated Than a Fresh Knife Blade.

INTRODUCTION: The rationale for discarding the skin knife blade and replacing it with another blade for deeper dissection is to prevent bacteria that may be present on the skin from being carried into the deeper layers of the wound. This practice is very controversial because numerous, yet limited, studies exist that support and refute the findings. The purpose of this study was to directly compare the rate of contamination of a skin knife blade with a control blade. METHODS: We took the surface samples using Replicate Organism Detection and Counting plates of 344 knife blades immediately after making skin incision during the following four types of orthopaedic cases: total hip arthroplasty, total knee arthroplasty, lumbar spine surgery, and cervical spine surgery. At the same time, we sampled 344 control blades. The comparison of positives skin versus control, overall and within each subgroup was done using a bivariate two-sample z-test for the equality of proportions. RESULTS: Overall, 35 (5.1%) of the 688 specimens had a positive result. No difference was noted in the rate of positive cultures for the 344 skin blades 4.9% and the 344 control blades 5.2%. No differences were observed in the rate of positive specimens for skin blades (7.4%, 3.4%, 7.7%, and 3.9%) and control blades (2.5%, 4.1%, 7.7%, and 9.2%) for total hip arthroplasty, total knee arthroplasty, C spine, and L spine, respectively. No differences were observed regarding skin prep, room number, case order, room turnover time, or in-room to incision time. Staphylococus species was the predominant bacteria identified. CONCLUSION: We found no evidence to support the theoretical advantage of changing the knife blade after making skin incision to avoid contamination. Contamination rates were the same for both the skin and control blades overall and for all subgroup analysis.