A Three-dimensional Comparison of Pre- and Post-component Position in a Series of Off-label Robotic-assisted Revision Total Knee Arthroplasties.

Background: The application of robotic-assisted arthroplasty in revision knee scenarios continues to evolve. This study compares the pre- and post-revision implant positions in series of revision total knee arthroplasties (TKA) using a robotic arm system. Methods: Twenty-five consecutive off-label robotic-assisted revision TKA were performed. After virtual revision femoral and tibial components were positioned to achieve "balanced" medial and lateral flexion and extension gaps, the existing primary implants (PI) were removed, and bone cuts were executed with the robotic arm system. Preoperative coronal, sagittal, and axial position of the PI was compared to the final planned positions of the robotic revision implants (RRI) for each subject. A repeated measures ANOVA using the absolute difference in millimeters and degrees between the PI and RRI orientation was completed. Results: Intra-operatively, the virtual gaps were balanced within the planning software followed by successful execution of the plan. There was a statistically significant difference between posterior condylar offset and tibial component positioning for RRI compared to PI. There was no difference between the distal femoral component values between PI and RRI. Conclusions: The sagittal alignment of the revision implants, specifically the femoral posterior condylar offset and tibial component slope, are statistically significant considerations for a stable revision TKA with off-label use of a robotic-arm system. Other potential benefits may include appropriate implant sizing which can affect the resultant ligamentous tension important for a functional revision TKA. Future research and software iterations will be needed to determine the overall accuracy and utility of robotic-assisted revision TKA.

Safe Sex After Total Hip Arthroplasty: Using Computed Tomography-Based Robotics to Evaluate "At-Risk" Sexual Positions.

BACKGROUND: Total hip arthroplasty (THA) can improve sexual satisfaction, but fear of dislocation can lead to sexual difficulties following this procedure. Previous kinematic research identified 4 sexual positions in women and 2 in men that were considered at risk for impingement. This study aimed to validate these findings using current robotic THA simulations. METHODS: The 3-dimensional renderings from 12 patients who received computed tomography (CT)-based robotic THA were used to assess for prosthetic and/or bony impingement among 12 popular sexual positions. There were 9 cup orientations tested for each position (a combination of anteversion [0 °, 15 °, and 30 °] and inclination [40 °, 45 °, and 60 °]). The at-risk positions were tested again using the unique hip positions and cup orientations where previous geometric modeling data found impingement to occur. RESULTS: Using mean hip positions, impingement occurred in at least 1 patient in 1 of the 12 positions for women (position 5) and 5 of the 12 positions for men (positions 1, 5, 8, 10, and 11). Among the at-risk positions, impingement occurred in none of the 2 at-risk women positions (0 of 17 cup orientations) and in both at-risk men positions (9 of 9 cup orientations for position 8 and 1 of 1 for position 11). CONCLUSION: Recreating popular and at-risk sexual positions following THA with a CT-based robotics system yielded results that were inconsistent with previous geometric modeling data. Resolving these discrepancies is crucial for surgeons to provide accurate postoperative patient education. The CT-based robotic systems may provide necessary input to feasibly individualize such recommendations, but current limitations in CT-based robotics require continued attention and innovation.

Rasch Analysis of Joint Replacement Version for Hip Disability and Osteoarthritis Outcome in Individuals With Advanced Osteoarthritis of Hip Awaiting Total Hip Arthroplasty Surgery.

OBJECTIVE: The objective of this study was to examine measurement properties of the Joint replacement version for Hip Disability and Osteoarthritis Outcome Score (HOOS-JR) using Rasch analysis in patients with osteoarthritis of hip (HOA). DESIGN: Cross-sectional clinical measurement SETTING: Patient outcomes database at a tertiary care hospital PARTICIPANTS: Convenience sampling of patients with HOA scheduled for total hip arthroplasty (N=327) OUTCOME MEASURES AND ANALYSIS: The data for pre-surgery assessments for patients with HOA were extracted from an existing database. Variables extracted included HOOS-JR scores, demographic information (age, sex), health-related data, and anthropometric variables. The assumptions of Rasch model such as the test of fit, fit residuals, ordering of item thresholds, factor structure, DIF, internal consistency and Pearson separation index were examined for the HOOS-JR scores. RESULTS: The HOOS-JR showed adequate overall fit to the Rasch model, logically ordered response thresholds, no floor or ceiling effects, and high internal consistency (Cronbach's alpha of 0.91). The HOOS-JR did not satisfy the assumption of unidimensionality, albeit the violation of this assumption was marginal (6.12% over 5%). Person-item threshold distribution (difference between person and item means were equal to 0.92 which was less than 1 logit unit) confirmed that the HOOS-JR scores were well targeted. CONCLUSIONS: Given that the violation of unidimensionality for HOOS-JR was marginal, we recommend further studies to validate this finding. Results broadly support the use of HOOS-JR for assessing hip health in patients with HOA.

Comparing dislocation rates by approach following elective primary dual mobility total hip arthroplasty: a systematic review.

BACKGROUND: Dual mobility components can be implanted during total hip arthroplasty (THA) for primary osteoarthritis via a direct anterior approach (DAA), anterolateral approach (ALA), direct lateral approach (DLA), or posterior/posterolateral approach (PLA). This review compares dual mobility hip dislocation rates using these approaches for elective primary THA. METHODS: PubMed, Embase, and Cochrane databases were systematically searched for articles published after January 1, 2006 that reported dislocation rates for adult patients after primary THA with dual mobility implants. Articles were excluded if they reported revision procedures, nonelective THA for femoral neck fractures, acetabular defects requiring supplemental implants, prior surgery, or ≤ 5 patients. The primary outcome was hip dislocation rate. Secondary outcomes included infection, Harris Hip Score (HHS), and Postel-Merle d'Aubigné (PMA) score. RESULTS: After screening 542 articles, 63 met inclusion criteria. Due to study heterogeneity, we did not perform a meta-analysis. Eight studies reported DAA, 5 reported ALA, 6 reported the DLA, and 56 reported PLA. Study size ranged from 41 to 2,601 patients. Mean follow-up time ranged from 6 months to 25 years. Rates of infection and dislocation were low; 80% of ALA, 87.5% of DAA, 100% of DLA, and 82.1% of PLA studies reported zero postoperative dislocations. Studies reporting postoperative HHS and PMA scores showed considerable improvement for all approaches. CONCLUSIONS: Patients undergoing primary THA with dual mobility implants rarely experience postoperative dislocation, regardless of surgical approach. Additional studies directly comparing DAA, ALA, DLA, and PLA are needed to confirm these findings.

The Effect of Working Time and Application Technique on Cement Penetration into a Tibial Model.

Background: Aseptic loosening of the cemented tibial component is a source of failure in total knee arthroplasty. This study examined common techniques for cement application by quantifying depth and volume of penetration into tibia models. Material and methods: Thirty-six composite tibia models were cemented with a tibial component using 3 application techniques (gun, osteotome, and layered) with either early or late cement working time. Computed tomography and 3D-modeling were used to quantify volume and depth of penetration. Statistical analysis was conducted with analysis of variance with Bonferroni correction and Student's t-test. Results: No difference was found in overall volume of penetration between early and late cement application (P = .16). Beneath the baseplate, the layered technique had significantly less penetration and averaged less than 3 mm with early and late cement. The gun technique had the greatest depth of penetration with early cement and averaged greater than 3 mm in all zones regardless of cement working time. The osteotome technique achieved significantly greater depth of penetration around the keel with early and late cement, P < .01. Conclusions: Using a cement gun ensures adequate penetration beneath the baseplate regardless of cement working time while the osteotome technique is effective to increase penetration around the implant keel. According to our study, applying cement early in its working time may not increase volume of penetration. This study raises concern regarding adequate cement penetration using the layered technique for cementing the tibial component in total knee arthroplasty, and future research is warranted.

An Update on Physical Therapy Adjuncts in Orthopedics.

Physical therapy is a necessary part of the recovery process after most orthopedic procedures. Effective treatment, patient satisfaction, and financial reimbursement hinge on the successful implementation of both surgical and nonsurgical interventions. Evidence-based practice and open communication between therapists and orthopedic surgeons continue to form the foundation of patient care. The aim of this paper is to familiarize orthopedic surgeons with the relevant data behind some of the recent advances in rehabilitation adjuncts to better address the needs of our patients. Although each intervention has been found to be relatively safe, high-quality evidence is still sparse. Opportunities exist for improved outcomes with further well-designed studies to investigate the role of these therapy modalities among orthopedic patients.

Postoperative Fluid Collections in Total Joint Arthroplasty: A Narrative Review.

A post-operative fluid collection (POFC) represents a common finding in both primary and revision total joint arthroplasty (TJA). Fortunately, most resolve on their own, but in instances where they become symptomatic, prompt identification and management are paramount, especially when they occur adjacent to a joint arthroplasty because of the increased the risk of developing a periprosthetic joint infection. A strong clinical suspicion with appropriate clinical exam is required along with select imaging modalities to arrive at a diagnosis. Meticulous surgical technique is crucial to prevent POFC, but new emerging treatments continue to evolve. This article presents an updated overview of incidence, pathophysiology, diagnosis, and management of POFC in the setting of TJA. We review the role of select imaging modalities as well as summarize current literature regarding new treatments such as sclerotherapy agents, acellular dermal matrices, and negative pressure wound therapy. Future studies are necessary to explore the interplay of inflammatory mediators in POFC formation and to define their role in fluid collection resolution.

Revision Total Knee Arthroplasty Using Robotic Arm Technology.

Total knee arthroplasty (TKA) is a highly successful operation for the treatment of end-stage osteoarthritis of the knee. Increasing use of computer-assisted and robotic-assisted total joint arthroplasty has been shown to improve component position, with short-term studies demonstrating improved survivability in unicompartmental knee arthroplasty. Robotic-assisted technology has been shown to be helpful in revising unicompartmental knee arthroplasty to TKA, as well as hip fusion to total hip arthroplasty, but few have described revision of a primary TKA. This case report describes the use of robotic-assisted technology in revision TKA. Robotic assistance during revision TKA may improve component alignment and increase prosthesis longevity. Future research is needed to investigate the effects on survivorship and cost.

An Interesting Case of Osteolysis With Accompanying Metallosis in a Primary Total Knee Arthroplasty.

Arthroplasty implants are comprised of metal alloys designed to function within the human body. Implant-related issues and associated soft-tissue reactions have been well documented for modular revision hip and knee constructs. This case highlights findings of metallosis in the context of polyethylene wear in a failed primary total knee arthroplasty. Fretting of a polyethylene reinforcement pin within the tibial baseplate as a direct result of knee joint instability appears to be the root cause of observed periprosthetic metallosis. Enhanced design principles and improved polyethylene locking mechanisms may be useful to potentially mitigate fretting-related issues in future knee replacement designs. The authors recommend surveillance in patients with this construct especially when prosthetic instability is present.

Conversion of Hip Arthrodesis Using Robotic Arm Technology.

Recent advancements in computer-assisted surgery have led to a renewed interest in robotic-assisted hip arthroplasty. This technology assists with component position which is especially useful in prior trauma or dysplasia cases. We present a case of a surgical hip fusion conversion to total hip arthroplasty with the use of robotic-assisted technology. Enhanced preoperative planning with the ability to manipulate implant position before execution can be invaluable during complex procedures. Further research is warranted before revision cases using computerized navigation systems becomes more prevalent.

The Expanding Role of Biomarkers in Diagnosing Infection in Total Joint Arthroplasty: A Review of Current Literature.

Consistent diagnosis of periprosthetic infection in total joint arthroplasty continues to elude the orthopedic surgeon because no gold standard test exists. Therefore clinicians must rely on a combination of tests to help aid the diagnosis. The expanding role of biomarkers has shown promising results to more accurately diagnose an infection when combined with clinical suspicion and bacterial culture testing. This paper reviews the diagnostic capabilities of the most current serum and synovial biomarkers as well as next generation sequencing in the setting of periprosthetic joint infection. Future research and high-powered studies will be necessary to determine sensitivity and specificity of each biomarker.

Incisionless Synovium and Bone Biopsy of a Painful Total Knee Arthroplasty.

Knee arthroscopy has evolved greatly from its inception in the 20th century. Arthroscopic synovectomy is performed in the case of infection or significant synovitis. We continue to develop more minimally invasive procedures, and the NanoScope (Arthrex, Naples, FL) has provided a new generation of possibilities. The system does not require the use of a standard incision or portal, and using the GraftNet (Arthrex), we can harvest tissue with a standard shaver for further evaluation. This technique provides an option to perform a synovial and bone biopsy in a painful total knee arthroplasty without the use of standard arthroscopy portals through an incisionless approach. This technique provides distinct advantages over a more open approach in the setting of a prosthetic joint. Specifically, this technique is useful for a difficult-to-diagnose painful total knee arthroplasty.

A Novel Technique to Detect Femoral Shaft Perforation during Direct Anterior Total Hip Arthroplasty.

Despite its popularity, the direct anterior approach for hip arthroplasty is not without complications. Intraoperative femoral shaft perforation using this approach ranges from 0.8% to 7%. A missed perforation can lead to fracture with the need for further surgery if not detected intraoperatively. We describe a reproducible and cost-effective technique using a plastic Yankauer suction handle to help identify proximal femoral perforations during direct anterior total hip arthroplasty. Careful attention to the visual, tactile, and auditory feedback provided by the suction handle can help ensure the cortical continuity of the proximal femur. Familiarity with relevant surgical anatomy, improving surgical technique, and scrutinizing implant positioning helps minimize the risk of complications during the direct anterior approach.

Arthroplasty during the COVID-19 Pandemic.

This article aims to give a brief outline of the pathogenesis and transmission of SARS-CoV-2 and how to safely navigate an arthroplasty practice during and after the pandemic.

Educating Surgeons to Educate Patients About the COVID-19 Pandemic.

The spring of 2020 has been a trying time for the global medical community as it has faced the latest pandemic, COVID-19. This contagious and lethal virus has impacted patients and health care workers alike. Elective surgeries have been suspended, and the very core of our health care system is being strained. The following brief communication reviews pertinent details about the virus, delaying elective surgeries, and what patients can do during this time. The goal is to disseminate factual data that surgeons can then use to educate their patients.

The risk factors and an evidence-based protocol for the management of persistent wound drainage after total hip and knee arthroplasty.

BACKGROUND: Persistent wound drainage (PWD) is one of the major risk factors for periprosthetic joint infections (PJIs), arguably the most dreaded complication after total joint arthroplasty (TJA). The aim of this study was to identify the risk factors for PWD and provide a stepwise management protocol for it. METHODS: A retrospective review of 4873 TJAs was performed. After determining patients with PWD, a logistic regression model was designed to identify the risk factors using Charlson and Elixhauser comorbidity indexes. Finally, the protocol that was instituted for the management of PWD and its success rate was presented. RESULTS: The prevalence of PWD was 6.2% (302 of 4873). Of these, 196 did not require any surgical interventions, and drainage stopped with local wound care. 106 patients required surgical intervention, of which, 64 underwent superficial irrigation and debridement and 42 underwent deep irrigation and debridement with modular components exchange. Patients with PWD had significantly higher rates of PJI (odds ratio [OR]: 16.9; 95% confidence interval [CI]: 9.1-31.6). Risks factors were diabetes (OR: 21.2; 95% CI: 12.8-25.1), morbid obesity (OR: 17.3; 95% CI: 14.7-21.5), rheumatoid arthritis (OR: 14.2; 95% CI: 11.7-16.5), chronic alcohol use (OR: 4.3; 95% CI: 2.3-6.1), hypothyroidism (OR: 2.8; 95% CI: 1.3-4.2), and female gender (OR: 1.9; 95% CI: 1.1-2.2). CONCLUSIONS: Several modifiable risk factors of PWD were identified. Surgeons must be cognizant of these comorbidities and optimize patients' general health before an elective TJA. Our results demonstrated that PWD ceased in about 65% of the patients with local wound care measures alone. Patients with PWD were at substantially higher risk for PJI.

Quantifying the force transmission through the pelvic joints during total hip arthroplasty: A pilot cadaveric study.

BACKGROUND: Total hip arthroplasty is one of the most successful and cost effective procedures in orthopedics. The purpose of this study is to investigate force transmission through the sacroiliac joint as a possible source of post-operative pain after total hip arthroplasty through the following three questions: Does the ipsilateral sacroiliac joint, contralateral sacroiliac joint, or pubic symphysis experience more force during placement? Does the larger mallet used to seat the implant generate a higher force? Does the specimen's bone density or BMI alter force transmission? METHODS: A solid design acetabular component was impacted into five human cadaver pelves with intact soft tissues. The pressure at both sacroiliac joints and the pubic symphysis was measured during cup placement. This same procedure was replicated using an existing pelvis finite element model to use for comparison. FINDINGS: The location of the peak force for each hammer strike was found to be specimen specific. The finite model results indicated the ipsilateral sacroiliac joint had the highest pressure and strain followed by the pubic symphysis over the course of the full simulation. The heft of the mallet and bone mineral density did not predict force values or locations. The largest median force was generated in extremely obese specimens. INTERPRETATION: Contrary to previous ideas, it is highly unlikely that forces experienced at the pelvic joints are large enough to contribute post-operative pain during impaction of an acetabular component. These results indicate more force is conveyed to the pubic symphysis compared to the sacroiliac joints.

Using a Modified Ball-Tip Guide Rod to Equalize Leg Length and Restore Femoral Offset.

Goals of total hip arthroplasty (THA) include pain alleviation, motion restoration, and normalization of leg-length inequality. Asymmetric leg lengths are associated with nerve traction injuries, lower extremity joint pain, sacroiliac discomfort, low back pain, and patient dissatisfaction. The authors present an innovative use of a modified ball-tip guide rod to help accurately restore leg length and femoral offset during direct anterior THA.