Can Robotic-Arm Assistance Decrease Iatrogenic Soft-Tissue Damage During Direct Anterior Total Hip Arthroplasty?

INTRODUCTION: Manual techniques for total hip arthroplasty (THA) have been widely utilized and proven to be clinically successful. However, the use of advanced computed tomography (CT) scan-based planning and haptically-bounded reamers in robotic-arm assisted total hip arthroplasty (RTHA) holds promise for potentially limiting surrounding soft-tissue damage. This cadaver-based study aimed to compare the extent of soft-tissue damage between a robotic-arm assisted, haptically-guided THA (RTHA) and a manual, fluoroscopic-guided THA (MTHA) direct anterior approach. MATERIALS AND METHODS: There were six fresh-frozen torso-to-toe cadaver specimens included, with two surgeons each performing three RTHA and three MTHA procedures. One hip underwent an RTHA and the other hip received an MTHA in each cadaver. Postoperatively, one additional surgeon, blinded to the procedures, assessed and graded damage to nine key anatomical structures using a 1 to 4 grading scale: (1) complete soft-tissue preservation to <5% of damage; (2) 6 to 25% of damage; (3) 26 to 75% of damage; and (4) 76 to 100% of damage. Kruskal-Wallis hypothesis tests were used to compare soft-tissue damage between RTHA and MTHA cases and adjusted for ties. RESULTS: Pooled analysis of the gluteus minimus, sartorius, tensor fascia lata, and vastus lateralis muscle grades demonstrated that cadaver specimens who underwent RTHA underwent less damage to these structures than following MTHA (median, IQR: 1.0, 1.0 to 2.0 vs. 3.0, 2.0 to 3.0; p=0.003). Pooled analysis of the calculated volumetric damage (mm3) for the gluteus minimus, sartorius, tensor fascia lata, and vastus lateralis muscles demonstrated that the cadaver specimens that underwent RTHA underwent less damage to these structures than those that followed MTHA (median, IQR: 23, 2 to 586 vs. 216, 58 to 3,050; p=0.037). CONCLUSION: This cadaver-based study suggests that utilizing RTHA may lead to reduced soft-tissue damage compared with MTHA, likely due to enhanced preoperative planning with robotic-arm assisted software, real-time intraoperative feedback, haptically-bounded reamer usage, reduced surgical steps, as well as ease of use with reaming. These findings should be carefully considered when evaluating the utilization of robotic-arm assisted THA in practice.

The Emergence of Collaboration in the Education of Fellows and Residents during COVID-19.

BACKGROUND: COVID-19 has created a void in surgical education. Given social distancing and postponed surgeries, unique educational opportunities have arisen. Attendings from 10 adult reconstruction fellowships led a multi-institution web-based weekly collaborative, the Arthroplasty Consortium (AC), developed to educate trainees through complex arthroplasty case-based discussions. METHODS: We performed an anonymous survey of AC participants and American Association of Hip and Knee Surgeons (AAHKS) adult reconstruction fellows. Participants were polled with regards to educational tools used before and after COVID-19 and their value. Specifically, participation in the AC, AAHKS FOCAL (Fellows Orthopedic Continued AAHKS Learning) lectures, institutional lectures, industry lectures, textbooks, online videos, journal articles, and webinars was assessed. RESULTS: Fifty-seven participants responded with 49 (86%) at the fellow level. There was an increase in the use of web-based learning, including the AC (Not applicable pre, 61% post), AAHKS FOCAL lectures (Not applicable pre, 82% post), industry lectures (53% pre, 86% post), and AAHKS/AAOS webinars (35% pre, 56% post). Usage declined with institutional lectures (89% pre, 80% post), textbooks (68% pre, 49% post), and journal articles (97% pre, 90% post), with minimal change in the use of online surgical videos (84% pre, 82% post). The majority of fellows not involved in the AC would like to see the addition of a multi-institutional case conference added to fellowship education. Of AC participants, the 2 most valuable educational tools were the AC and FOCAL lectures. CONCLUSION: Trainee education has changed post-COVID-19 with a greater focus on web-based learning. Multi-institutional collaborative lectures and case-based discussions have significant perceived value among trainees and should be considered important educational tools post-COVID 19.

Do sex and BMI predict or does stem design prevent muscle damage in anterior supine minimally invasive THA?

BACKGROUND: Cadaveric and clinical studies have suggested that, despite being touted as muscle-sparing, the direct anterior approach is still associated with muscle damage, particularly to the tensor fascia lata (TFL). Patient body mass index (BMI) and/or sex may also influence this parameter. QUESTIONS/PURPOSES: The purposes of the study were to determine if using a shorter femoral component reduces TFL damage or if patient sex or increasing BMI increases intraoperative TFL damage in direct anterior THA. METHODS: Over a 1-year period, 599 direct anterior THAs were performed by three experienced anterior hip surgeons; of those, 421 direct anterior hips had complete data (70%) and were included in the study. The amount of visible damage to the TFL was recorded before closure. Two stem types were used, a standard-length flat-wedge taper (standard) or a 3-cm shortened version of the same stem (short). Stem selection was based on timeframe of the surgery, surgeon preference, or matching a previous implant type. During the study period, the three surgeons performed an additional 225 primary THAs with other approaches such that the direct anterior approach represented 73% of the THAs performed. A member of the operating team, either a fellow or physician assistant, graded the extent of damage based on a 0 to 3 scale. On this scale, 0 represented no muscle fiber damage, 1 superficial tearing, 2 deep tearing or maceration, and 3 complete tear or severe damage. Patient sex and BMI were recorded and compared with stem type and muscle damage scores. An ordinal logistic regression model was used for statistical analysis. RESULTS: After controlling for relevant confounding variables using logistic regression, we found that mean muscle damage was associated with male sex (0.93, SD 0.76 versus 0.70, SD 0.68; p<0.001) and increasing BMI levels (p<0.001). As BMI increased, more muscle damage also was found in men compared with women (p=0.05; odds ratio [OR], 1.029; 95% confidence interval [CI], 1.000-1.060). There was no overall difference in mean muscle damage between short and standard-length stems (0.78, SD 0.77 versus 0.85, SD 0.69, p=0.32); however, as BMI increased, less damage was seen with a short stem (p=0.04; OR, 0.968; 95% CI, 0.931-0.997). CONCLUSIONS: Visible muscle damage occurred in most hips during anterior supine intermuscular hip arthroplasty. The clinical importance of this muscle damage requires further study, because some evidence suggests earlier restoration of gait and cessation of walking aids with direct anterior THA despite this damage; however, this was not studied here. Surgeons performing this approach can expect more difficulty and as a result possibly more damage to the TFL in patients with male sex and increased BMI. The use of a short stem can be considered for patients with increased BMI to limit damage to the TFL. LEVEL OF EVIDENCE: Level III, therapeutic study.

A Novel Protocol for Nasal Decolonization Using Prolonged Application of an Alcohol-Based Nasal Antiseptic Reduces Surgical Site Infections in Total Joint Arthroplasty Patients: A Retrospective Cohort Study.

Background: Current nasal decolonization strategies utilize pre-operative agents without consideration for short-term re-colonization or de novo colonization. Many strategies utilize an antibiotic-based agent, raising concerns of limited gram-negative antimicrobial coverage and the emergence of resistant bacterial strains. This study evaluated the clinical utility of a non-antibiotic, alcohol-based nasal decolonization agent in decreasing surgical site infection (SSI) rates after total joint arthroplasty. Patients and Methods: We retrospectively compared an 18-month cohort of elective primary total joint arthroplasty patients treated peri-operatively with an alcohol-based sanitizer to historical controls. The alcohol-based agent was administered pre-operatively the day of surgery and for two weeks after surgery. Patients were followed for 90 days and assessed for signs or symptoms of SSI. Patient and caregiver compliance was recorded. There were 779 patients included in the experimental group and 647 included in the historical control group. Results: Patients receiving alcohol-based nasal decolonization had a lower rate of SSI compared with controls not receiving nasal decolonization (0.64% [5/779] vs. 1.55% [10/647]; p = 0.048; odds ratio, 2.43). Utilization of an alcohol-based nasal sanitizer in the pre-operative and prolonged post-operative setting decreased infection rates by 41.3% in our elective total joint arthroplasty setting. Conclusions: When used pre- and post-operatively, alcohol-based nasal decolonization of bacteria in patients undergoing total joint arthroplasty led to a substantial decrease in SSIs.

Operative treatment of adolescent clavicle fractures with an intramedullary clavicle pin.

BACKGROUND: Adolescent clavicle fractures have traditionally been treated nonoperatively; however, recent literature in adults has shown improved outcomes with operative treatment of displaced and shortened clavicle fractures. It has been suggested that these results may translate to adolescents. This study presents an initial look at outcomes for operative treatment of displaced midshaft clavicle fractures in adolescents using an intramedullary clavicle pin. METHODS: Seventeen adolescent patients treated for a displaced, shortened midshaft clavicle fracture with an intramedullary clavicle pin between November 2007 and August 2009 were evaluated. Preoperative displacement, fracture union, and complications were reviewed, and shoulder scores were determined using the patient self-report section of the American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form. RESULTS: Fracture union occurred in all 17 patients by 12 weeks. Average patient age was 15.8 years and ranged from 13 to 18 years. All but 2 implants were electively removed. The most common postoperative complaint was prominent hardware, which resolved after elective removal. There were no infections and only 1 patient reported decreased sensation at the incision site. Ten patients returned the American Shoulder and Elbow Surgeons form at an average time of 16.6 months after surgery. The average pain score was 44.2 of a possible 50 points. The average functional score was 44.3 of a possible 50 points. No patients reported severe difficulty with work activities and only 1 patient reported severe difficulty with sporting activities. CONCLUSIONS: Operative treatment with an intramedullary clavicle pin seems to be a safe and effective treatment method for displaced midshaft clavicle fractures in adolescents. LEVEL OF EVIDENCE: Therapeutic level IV.

Effect of femoral component design on patellofemoral crepitance and patella clunk syndrome after posterior-stabilized total knee arthroplasty.

The purpose of this study was to determine if recent changes to the femoral component of a particular posterior-stabilized total knee prosthesis would affect the incidence of postoperative patellofemoral crepitance and patella clunk syndrome. One hundred eight total knee arthroplasties were performed with the conventional design; 136 were performed after the femoral component was changed. Complications were compared between the groups with an average follow-up of 17.7 months and 12.4 months, respectively. Thirteen knees with the conventional design (12%) were found to have patellofemoral complications; no complications were noted with the new design (P < .0001). Femoral components with a deep trochlear groove and smooth transition of the intercondylar box appear to better accommodate any peripatellar fibrous nodule that may form after total knee arthroplasty.

Randomized Trial of Postoperative Venous Thromboembolism Prophylactic Compliance: Aspirin and Mobile Compression Pumps.

BACKGROUND: Aspirin, as a routine venous thromboembolism (VTE) prophylaxis, is approved along with pneumatic compression pumps by the American College of Chest Physicians. We assessed compliance of aspirin and pump use after total joint arthroplasty. METHODS: A randomized trial of aspirin alone or aspirin/mobile compression pumps after total joint arthroplasty was performed. Aspirin and pump compliance, VTE events, and satisfaction with pump use were collected. Compliance was assessed through an internal device monitor and drug log book. Patients were also contacted 90 days postoperatively for reported symptomatic VTEs. RESULTS: Each group had 40 patients and greater than 94% compliance with aspirin use, with no difference between groups (P = 0.55). Overall pump compliance during the first 14 days after hospital discharge was 51% (SD ± 33), which was significantly worse than aspirin compliance at 99% (SD ± 4.1) (P < 0.0001). Only 10 patients were compliant (>20 hr/d) with recommended pump use throughout the entire recommended period. There was no notable association between aspirin compliance and VTE within 90 days. There was no notable association between pump compliance and VTE at 90 days. However, average pump use compliance was 20% in patients with VTE and 54% in patients without VTE within 90 days. With the numbers available in this compliance study, there was no significant difference (P = 0.11). DISCUSSION: Aspirin compliance was notably greater than pump compliance. In this study, we found that pump compliance was not associated with lower VTE risk. In fact, no increased risk was recognized in patients with an average pump usage of >50%. Further study is warranted to define the duration of pump use required for clinical significance. The recommended use of compression pumps should continue to be examined.

The Oxinium Arthrogram: A Sign of Oxidized Zirconium Implant Failure.

Oxinium implants are composed of a zirconium alloy with a hard ceramic surface formed by oxidization of the outer layer. This material has been shown to be an effective bearing surface for total joint arthroplasty and an alternative material for use in patients with metal hypersensitivity. Reports exist of metallosis due to unintended wear of Oxinium components from multiple mechanisms including polyethylene liner dissociation and joint instability. This metallosis creates a distinct appearance on radiographic imaging similar to that of an arthrogram. We report 2 cases of metallosis and describe the characteristic radiographic appearance of failed oxidized zirconium implants.

Complex Primary Total Hip Arthroplasty: Small Stems for Big Challenges.

Total hip arthroplasty is one of the most successful operations in all of medicine. Femoral deformities from malunion, prior osteotomy, and retained surgical implants all present unique challenges. Corrective osteotomy and hardware removal add significant morbidity to an operation that typically has a fast recovery. Short stems can be used in these cases to spare patients' increased morbidity. We present a case-based illustration and surgical technique for the use of short stems in complex primary total hip arthroplasty with femoral deformity and retained hardware. We discuss how these implants can spare significant morbidity, show radiographic examples of their use, and present short-term outcomes.

A Medial Congruent Polyethylene Offers Satisfactory Early Outcomes and Patient Satisfaction in Total Knee Arthroplasty.

BACKGROUND: Although a successful operation, almost 20% of patients are dissatisfied with total knee arthroplasty (TKA). The purpose of this retrospective cohort study was to see if a medial congruent (MC) polyethylene would offer satisfactory early outcomes and patient satisfaction after TKA. METHODS: We reviewed prospectively collected data on 327 TKAs using multiple bearings within the same implant system. Ninety-six received an MC bearing, 70 received a cruciate-retaining (CR) bearing, and 161 received a posterior-stabilized (PS) bearing. We evaluated the visual analog scale pain scores and range of motion (ROM) at 2 weeks, 6 weeks, 3 months, and 1 year; Patient-Reported Outcomes Measurement Information System (PROMIS-10) score and Knee Injury and Osteoarthritis Outcome Score (KOOS) at 3 months and 1 year; and Forgotten Joint Score (FJS-12) at 1 year. RESULTS: All groups had similar KOOS and PROMIS-10 scores. MC knees had lower visual analog scale scores than PS knees at all time points (P < .05) and a higher ROM than PS at 2 weeks (98.6 vs 93.7, P = .002). MC knees had a significantly higher FJS-12 than CR knees (71.6 vs 58.7, P = .02). More MC knees were "very satisfied" than CR (92.6% vs 81.5%, P = .04). Fewer MC knees were "not at all satisfied" than CR (1.2% vs 9.2%, P = .04). There were similar satisfaction ratings with MC and PS. CONCLUSIONS: An MC bearing provided similar or improved early pain, ROM, KOOS, PROMIS-10, FJS-12, and patient satisfaction as compared with standard bearings in TKA.

Liposomal Bupivacaine Offers No Benefit Over Ropivacaine for Multimodal Periarticular Injection in Total Knee Arthroplasty.

Local infiltration analgesia has become a mainstay of pain control for total knee arthroplasty. This study compared the efficacy and cost between periarticular injection cocktails containing liposomal bupivacaine vs ropivacaine. Two hundred forty-two primary total knee arthroplasties performed between September 2013 and January 2016 were retrospectively reviewed. All patients received similar pre-operative medications and a periarticular injection. The control group received 300 mg of ropivacaine, while the study group received liposomal bupivacaine. All patients received the same preoperative, intraoperative, and postoperative adjunct medications. Visual analog scale pain scores, narcotic requirements, distance walked, range of motion, length of stay, Knee Society Scores, and need for manipulation under anesthesia were recorded. Mean visual analog scale pain score 23 to 32 hours postoperatively, mean visual analog scale pain score during the entire hospitalization, and length of stay were lower in the ropivacaine group compared with the liposomal bupivacaine group. Knee range of motion was higher at 2 weeks in the ropivacaine group. There were no statistically significant differences in the other outcome measures. The cost of ropivacaine was considerably lower than the cost of liposomal bupivacaine. Bupivacaine added to liposomal bupivacaine addressed the delayed onset of this medication and gave an accurately matched comparison with the ropivacaine cocktail. All outcomes tested with liposomal bupivacaine were either equivalent or inferior to those with ropivacaine. When used as a component of a periarticular injection cocktail, liposomal bupivacaine offers no advantages over ropivacaine and has a considerably higher cost. [Orthopedics. 2020; 43(2):91-96.].

Portable compression devices in total joint arthroplasty: poor outpatient compliance.

BACKGROUND: Aspirin and mechanical compression devices are approved means of venous thromboembolism (VTE) prophylaxis after total joint arthroplasty. Prior studies of mechanical compression pumps after joint arthroplasty have been limited to the inpatient setting. The purpose of this study was to evaluate outpatient compliance and utilization factors in a rural population after elective hip or knee arthroplasty. METHODS: Utilization for portable pneumatic compression pumps after joint arthroplasty was prospectively recorded (hours). Compliance was defined as the recommended 20 hours per day. A questionnaire 2 weeks postoperatively assessed factors that may contribute to noncompliance. Patients were followed up for 90 days postoperatively to record VTE events. RESULTS: Data were collected for 115 joint arthroplasty patients (50 hips, 65 knees). Postdischarge day one had the highest average usage at 13.2 hours/day (66.0%, range 0%-100%), but this number fell to 4.8 hours/day (24.0, range 0%-100%) by day 14. Patient compliance (>20 hours use/day) was highest on postdischarge day one at 40 patients (34.7%). By postdischarge day 14, patient compliance fell to 17 patients (14.8%). Difficulty using the pumps (P = .027) and pump-associated heat (P = .009) were significantly associated with patient compliance. A deep vein thrombosis and nonfatal pulmonary embolism were recorded in 2 separate patients. CONCLUSIONS: This study demonstrated poor outpatient compliance with portable pneumatic compression devices. Poor compliance was related to pump heat and difficulty with pump use. Even with poor compliance, a low incidence of VTE events was observed.

Rate of surface contamination in the operating suite during revision total joint arthroplasty.

BACKGROUND: This study estimated operating room surface contamination rates during aseptic vs septic total joint arthroplasty and evaluated the similarity between clinically infecting organisms and those isolated from contaminated surfaces. METHODS: Patients undergoing total hip and knee revision arthroplasties were identified, and surface and tissue samples were collected. Cases were classified aseptic or septic based on Musculoskeletal Infection Society criteria for prosthetic joint infection. Positive surface cultures were compared with intraoperative tissue cultures. Positive cultures were speciated and tested for antimicrobial sensitivity. RESULTS: Samples were collected from 31 aseptic and 18 septic cases. Patients had similar demographics and time to explantation. Surface contamination rates for septic revisions were greater than those for aseptic revisions (77% vs 13%). During septic revisions, when intraoperative tissue cultures were positive, the surgical field was contaminated in 14 of 15 cases. The kappa correlation statistic for positive surgical cultures matching the surface sample was 0.9 (95% confidence interval: 0.78-1). CONCLUSIONS: Septic revisions had a significantly higher rate of surgical field contamination than aseptic revisions. Cultures suggest that bacteria contaminating the septic revision surgical field likely originated from the infected joint. Although this observation seems obvious, it is an important piece of information when discussing best practices during a single-stage exchange revision. Further clinical studies will demonstrate the use of a preparation and reset period during a single-stage revision to remove contaminated surfaces.

Smartphone assessment of knee flexion compared to radiographic standards.

BACKGROUND: Measuring knee range of motion (ROM) is an important assessment for the outcomes of total knee arthroplasty. Recent technological advances have led to the development and use of accelerometer-based smartphone applications to measure knee ROM. The purpose of this study was to develop, standardize, and validate methods of utilizing smartphone accelerometer technology compared to radiographic standards, visual estimation, and goniometric evaluation. METHODS: Participants used visual estimation, a long-arm goniometer, and a smartphone accelerometer to determine range of motion of a cadaveric lower extremity; these results were compared to radiographs taken at the same angles. RESULTS: The optimal smartphone position was determined to be on top of the leg at the distal femur and proximal tibia location. Between methods, it was found that the smartphone and goniometer were comparably reliable in measuring knee flexion (ICC=0.94; 95% CI: 0.91-0.96). Visual estimation was found to be the least reliable method of measurement. CONCLUSIONS: The results suggested that the smartphone accelerometer was non-inferior when compared to the other measurement techniques, demonstrated similar deviations from radiographic standards, and did not appear to be influenced by the person performing the measurements or the girth of the extremity.

Comparing Cost, Efficacy, and Safety of Intravenous and Topical Tranexamic Acid in Total Hip and Knee Arthroplasty.

We conducted a study to compare the cost, efficacy, and safety of intravenous (IV) tranexamic acid (TXA) and topical TXA in primary total hip arthroplasty (THA) and total knee arthroplasty (TKA). We retrospectively reviewed the cases of 291 patients who received either IV TXA or topical TXA before and after surgery. Significant differences favored topical TXA in reducing the postoperative decrease in hemoglobin levels in THA (P = .031) and TKA (P = .015) and calculated blood loss in TKA (P = .019). The groups did not differ in transfusion requirements for either THA or TKA. Topical TXA cost significantly more than IV TXA (P ≤ .0001). The benefits of using topical TXA to reduce the perioperative decrease in hemoglobin levels come with increased cost.

MRI is more accurate than CT for patient-specific total knee arthroplasty.

Previous reports have stated that MRI is less accurate than CT for patient specific guide creation in total knee arthroplasty (TKA). Twenty-three TKAs were performed with CT-based guides and 27 with MRI-based guides. A mechanical axis through the central third of the knee was achieved in 88.9% of MRI-guided TKA versus 69.6% of CT-guided TKA (p=0.07). There were nine component outliers in the CT group (39.1%) and two in the MRI group (7.4%, p=0.00768). The relative risk of having an outlier using a CT-based guide was 5.28 times that of an MRI-based guide. Superior overall alignment and fewer outliers were achieved with the use of MRI compared with CT. MRI is the best imaging modality for surgeons wishing to utilize patient specific guides for TKA.

Customization of cutting blocks: Can this address the problem?

Recent literature has challenged the notion that neutral coronal alignment is a requirement for long-term survivorship of TKAs. However a preponderance of classic and contemporary evidence supports increased failure rates with malalignment, especially varus. Patient-specific custom cutting guides are an attractive alternative to traditional instrumentation and computer navigation in achieving accurate alignment of total knee arthroplasties. The logistical benefits include possible decreased operating room time, decreased turnover time, less time spent sterilizing and preparing trays, less inventory, less strain on surgical technicians and nurses, and no capital cost associated with computer navigation. Patient benefits include potentially less tourniquet time, less surgical exposure, no requirement of intramedullary canal preparation, and improved mechanical alignment, which may translate to increased implant longevity. Surgeon benefits include potentially more accurate landmark registration than computer navigation, more efficient surgery, decreased intraoperative stress due to less required decision making, and the ability to perform more surgeries due to time saved.