Total Knee Arthroplasty Periprosthetic Joint Infection with Concomitant Extensor Mechanism Disruption and Soft-Tissue Defect: The Knee Arthroplasty Terrible Triad.

BACKGROUND: Periprosthetic infection (PJI) with concomitant extensor mechanism disruption (EMD) and soft-tissue defect - hereinafter termed the "Terrible Triad" - is a devastating complication following total knee arthroplasty (TKA). The purpose of this study was to define the surgical and clinical outcomes following management of a cohort of patients who have the Terrible Triad. METHODS: From 2000 to 2022, 127 patients underwent operative management for PJI alone, 25 for PJI with soft-tissue defects (defined as defects requiring flap reconstruction or being a factor contributing to the decision of performing above-knee amputation (AKA) or arthrodesis), 14 for PJI with EMD, and 22 for the Terrible Triad. A composite outcome of infection status, range of motion, extensor lag, and ambulatory status at final follow-up was used to compare the proportion of patients in each group with a favorable overall knee outcome. Differences between groups were determined using one-way analyses of variance with post hoc Tukey's tests and Pearson's Chi-square tests or Fisher's exact tests with post hoc Bonferroni adjustments, where applicable. Odds ratios (OR) were calculated for comparison of the overall knee outcome between groups. A Kaplan-Meier survival analysis for patient mortality was performed. RESULTS: The mean follow-up was 8.4 years and similar between groups (P = 0.064). Patients who had the Terrible Triad had a 45.5% incidence of AKA, or arthrodesis, and an 86.4% incidence of an unfavorable outcome. Compared to patients in the PJI group, patients in the PJI who had a soft-tissue defect (OR=5.8, 95%CI [confidence interval] 2.2 to 15.7), PJI with EMD (OR=3.7, 95%CI 1.0 to 12.9), and Terrible Triad groups (OR=11.6, 95%CI 3.3 to 41.5) showed higher odds of an unfavorable knee outcome. CONCLUSIONS: This study demonstrates that the TKA Terrible Triad is a dreaded diagnosis with poor outcomes. Clinicians and patients might consider early treatment with amputation or arthrodesis.

Clinical applications of augmented reality in orthopaedic surgery: a comprehensive narrative review.

PURPOSE: The development of augmented reality (AR) technology allows orthopaedic surgeons to incorporate and visualize surgical data, assisting the execution of both routine and complex surgical operations. Uniquely, AR technology allows a surgeon to view the surgical field and superimpose peri-operative imaging, anatomical landmarks, navigation guidance, and more, all in one view without the need for conjugate gaze between multiple screens. The aim of this literature review was to introduce the fundamental requirements for an augmented reality system and to assess the current applications, outcomes, and potential limitations to this technology. METHODS: A literature search was performed using MEDLINE and Embase databases, by two independent reviewers, who then collaboratively synthesized and collated the results of the literature search into a narrative review focused on the applications of augmented reality in major orthopaedic sub-specialties. RESULTS: Current technology requires that pre-operative patient data be acquired, and AR-compatible models constructed. Intra-operatively, to produce manipulatable virtual images into the user's view in real time, four major components are required including a camera, computer image processing technology, tracking tools, and an output screen. The user is provided with a heads-up display, which is a transparent display, enabling the user to look at both their natural view and the computer-generated images. Currently, high-quality evidence for clinical implementation of AR technology in the orthopaedic surgery operating room is lacking; however, growing in vitro literature highlights a multitude of potential applications, including increasing operative accuracy, improved biomechanical angular and alignment parameters, and potentially reduced operative time. CONCLUSION: While the application of AR systems in surgery is currently in its infancy, we anticipate rapid and widespread implementation of this technology in various orthopaedic sub-specialties.

Distal femoral replacement or internal fixation for management of periprosthetic distal femur fractures: A systematic review.

BACKGROUND: The number of periprosthetic fractures above a total knee arthroplasty continues to increase. These fractures are associated with a high risk of morbidity and mortality. Techniques for addressing these fractures include open reduction internal fixation (ORIF) and revision arthroplasty, including distal femoral replacement (DFR). The primary aim of this review is to compare mortality and reoperation rates between ORIF and DFR when used to treat periprosthetic distal femur fractures. METHODS: A systematic review including MEDLINE, Embase and Cochrane Library databases was completed from inception to April 10, 2021. Studies including a comparator cohort were meta-analyzed. RESULTS: Fourteen studies were identified for inclusion, of which, five had sufficient homogeneity for inclusion in a meta-analysis. 30-day and 2-year mortality was 4.1% and 14.6% in the DFR group. There was no statistically significant difference between ORIF and DFR (log Odds-Ratio (OR) = -0.14, 95 %CI: -0.77 to 0.50). The reoperation rate in the DFR group was 9.3% versus 14.8% for ORIF, with no difference between groups (log OR = 0.10, 95 %CI: -0.59 to 0.79). There was no difference in rates of deep infection (log OR = 0.22, 95 %CI: -0.83 to 1.28). Direct comparison of functional outcomes was not possible, though did not appear significant. CONCLUSION: DFR in the setting of periprosthetic distal femur fractures is equivalent to ORIF with respect to mortality and reoperation rate and thus a safe and reliable treatment strategy. DFR may be more reliable in complex fracture patterns where the ability to obtain adequate fixation is difficult.

Reducing Acute Hospitalization Length of Stay After Total Knee Arthroplasty: A Quality Improvement Study.

BACKGROUND: The introduction of bundled funding for total knee arthroplasty (TKA) has motivated hospitals to improve quality of care while minimizing costs. The aim of our quality improvement project is to reduce the acute hospitalization length of stay to less than 2 days and decrease the percentage of TKA patients discharged to inpatient rehabilitation using an enhanced recovery after surgery bundle. METHODS: This study used a before-and-after design. The pre-intervention period was January to December 2017 and the post-intervention period was January 2018 to August 2019. A root cause analysis was performed by a multidisciplinary team to identify barriers for rapid recovery and discharge. Four new interventions were chosen as part of an improvement bundle based on existing local practices, literature review, and feasibility analysis: (1) perioperative peripheral nerve block; (2) prophylactic antiemetic medication; (3) avoidance of routine preoperative urinary catheterization; and (4) preoperative patient education. RESULTS: The pre-intervention and post-intervention groups included 232 and 383 patients, respectively. Mean length of stay decreased from 2.82 to 2.13 days (P < .001). The need for inpatient rehabilitation decreased from 20.2% to 10.7% (P = .002). Mean 24-hour oral morphine consumption decreased from 60 to 38 mg (P < .001). The percentage of patients experiencing moderate-to-severe pain and postoperative nausea and vomiting within the first 24 hours decreased by 25% and 15%, respectively (P < .001). Thirty-day emergency department visits following discharge decreased from 12.9% to 7.3% (P = .030). CONCLUSION: Significant improvements in the recovery of patients after TKA were achieved by performing a root cause analysis and implementing a multidisciplinary, patient-centered enhanced recovery after surgery bundle. LEVEL OF EVIDENCE: Level III.

Evaluation of the Medial Stabilized Knee Design Using Data From National Joint Registries and Current Literature.

BACKGROUND: Various designs of total knee arthroplasty (TKA) have provided satisfactory outcomes for the treatment of knee osteoarthritis for many years. The aim of the study is to evaluate the success and failure rate of the medial stabilized (MS) TKA design through national joint registries and the current literature. MATERIALS AND METHODS: A comprehensive literature review using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses was carried out through PubMed and MEDLINE database. The international registries analyzed included the National Joint Registry, the Australian Orthopedic Association National Joint Replacement Registry, the Dutch Arthroplasty Register, the New Zealand Orthopedic Association Joint Registry, and the Michigan Arthroplasty Registry Collaborative Quality Initiative. We are reporting descriptive data which include means and percentages of survival rates and revision rates and number of years after the primary procedure. The revision rates and the cumulative revision rates are reported separately for each MS implant. RESULTS: Our detailed review identified 5 of 12 registries and 25 of 550 studies reporting on the survivorship of an MS TKA design. There were a total of 3684 procedures between the 25 studies, with an average survivorship free of aseptic loosening of 99% at 6.9 years. There are 26,693 (2.5%) MS TKAs in the current National Joint Registry with a mean cumulative revision rate of 2.63% at 5 years, 3.35% at 10 years, and 4.6% at 15 years. The Australian Orthopedic Association National Joint Replacement Registry provides survivorship data on 19,249 (2.9%) MS TKAs, with a mean cumulative revision rate of 3.34% at 5 years, 7.4% at 10 years, and 8.1% at 15 years. The Dutch Arthroplasty Register contains survivorship data on 1490 MS designs and a mean revision rate of these implants is 0.8% at 1 year, 5.95% at 5 years, and 9.8% at 10 years. The Evolution MP is the only implant reported in the Michigan Arthroplasty Registry Collaborative Quality Initiative and has a revision rate of 2.28% at 3 years. CONCLUSION: The MS TKA design has comparable results to traditional TKA designs across several joint registries and 25 studies in the literature.

The Effect of Polyethylene Liner Thickness on Patient Outcomes and Failure After Primary Total Knee Arthroplasty.

BACKGROUND: The effect of using thicker liners in primary total knee arthroplasty (TKA) on functional outcomes and aseptic failure rates remains largely unknown. As such, we devised a multicenter study to assess both the clinical outcomes and survivorship of thick vs thin liners after primary TKA. METHODS: A search of our institutional databases was performed for patients having undergone bilateral (simultaneous or staged) primary TKA with similar preoperative and surgical characteristics between both sides. Two cohorts were created: thick liners and thin liners. Outcomes collected were as follows: change in Knee Society Score (ΔKSS), change in range of motion, and aseptic revision. Ad hoc power analysis was performed for ΔKSS (⍺ = 0.05; power = 80%). Differences between cohorts were assessed. RESULTS: About 195 TKAs were identified for each cohort. ΔKSS and change in range of motion in the thin vs thick cohorts were similar: 51.4 vs 51.6 (P = .86) and 11.1° vs 10.0° (P = .66), respectively. No difference in aseptic revision rates were observed between thin and thick cohorts: all cause (4.1%, 3.1%; P = .59), aseptic loosening (0.5%, 0.5%; P = 1.0), instability (0.5%, 0.5%; P = 1.0), all-cause revision for stiffness (3.1%, 2.1%; P = .52), manipulation under anesthesia (2.1%, 2.1%; P = 1.0), and liner exchange (0.5%, 0%; P = .32). CONCLUSION: The results of this study suggest that both rates of revision surgery and clinical outcomes are similar for TKAs performed with thick and thin liners. Preoperative factors are likely to play an important role in liner thickness selection, and emphasis should be placed on ensuring sound surgical technique.

The Development of a Standardized Pathway for Outpatient Ambulatory Fracture Surgery: To Admit or Not to Admit.

BACKGROUND: Increased scrutiny of health-care costs and inpatient length of stay has resulted in many orthopaedic procedures transitioning to outpatient settings. Recent studies have supported the safety and efficiency of outpatient fracture procedures. The aim of the present study was to reduce unnecessary inpatient hospitalizations for healthy patients awaiting surgical treatment of a fracture by 80% by June 30, 2017, with a focus on timely, efficient, and patient-centered care. METHODS: The study design was a time series using statistical process control methodology. Baseline data from October 2014 to June 2016 were compared with the intervention period from July 2016 to December 2018. The Model for Improvement was used as the framework for developing and implementing interventions. The main interventions were a policy change to allow booking of outpatient urgent-room cases, education for patients and nurses, and the development of a standardized outpatient pathway. RESULTS: One hundred and eighty-seven patients during the pre-intervention period and 308 patients during the intervention period were eligible for the ambulatory pathway. The percentage of patients managed as outpatients increased from 1.6% pre-intervention to 89.1% post-intervention. The length of stay was reduced from 2.8 to 0.2 days, a decrease of 94.0%. Patient satisfaction remained high, and there were no safety concerns while patients waited at home for the surgical procedure. CONCLUSIONS: The outpatient fracture pathway vastly improved the efficiency and timeliness of care and reduced health-care costs. A patient-centered culture and support from hospital administration were integral in producing sustainable improvement. LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

The Effectiveness of Repeat Two-Stage Revision for the Treatment of Recalcitrant Total Knee Arthroplasty Infection.

BACKGROUND: The gold-standard method in North America for the management of infected total knee arthroplasty is 2-stage revision arthroplasty. This has provided generally a high success rate. However, persistent infection after 2-stage revision knee arthroplasty does occur. The purpose of this study was to predict the success rate of second, 2-stage revision arthroplasty. METHODS: All infected total knee arthroplasty treated between 2000 and 2015 that were operated by a single senior surgeon were reviewed retrospectively. Patients were stratified according to general health and limb status according to the Musculoskeletal Infection Society (MSIS) scoring system. The reinfection rate at the last follow-up was identified. The chi-square test and Fisher exact test were used to compare binary variables. RESULTS: We found a statistical relationship between the higher stage of MSIS score, type of microorganism, flap surgery, and reinfection rate after reimplantation of second two-stage surgery. There is not any statistically significant correlation between age, gender, constraint pattern of prosthesis, number of spacers, and time interval between the first and second stages of second 2-stage surgery with the numbers available in this study. CONCLUSION: Another 2-stage knee revision is an effective method of treatment. However, we found a higher incidence of failure in those patients with poor general health based on the MSIS score, inadequate soft tissue envelope and resistant bacteria. The success of second, 2-stage protocol is best in patients with optimized general health, soft tissue coverage, and antibiotic-sensitive microorganism. Patients who cannot be optimized are most likely to require amputation or knee arthrodesis than another futile 2-stage surgery.

Synthetic Graft Compared With Allograft Reconstruction for Extensor Mechanism Disruption in Total Knee Arthroplasty: A Multicenter Cohort Study.

BACKGROUND: Extensor mechanism disruption after total knee arthroplasty is a serious complication leading to notable patient morbidity. The purpose of this study is to compare the outcomes of extensor mechanism allograft with synthetic graft reconstruction. METHODS: We retrospectively identified all patients who underwent extensor mechanism reconstruction using either allograft or synthetic graft from two high-volume academic arthroplasty institutions between 2006 and 2017. We collected extensor lag, need for ambulatory aids, and patient-reported outcome measures, as well as the incidence of postoperative complications and revision surgeries. We evaluated cost differences, considering both material cost and the need for revision surgery. RESULTS: We identified 27 cases. A significantly greater postoperative extensor lag was found in the allograft group (P = 0.05). Graft failure after synthetic reconstruction was zero, with an overall revision surgery rate of 15%. Graft failure was 21%, and the revision surgery rate was 43% after allograft reconstruction. The allograft cost was significantly higher compared with the synthetic graft cost (P = 0.001). The mean total cost was 4,733.08 CAD for the synthetic group and 24,050.40 CAD for the allograft group (P = 0.17). DISCUSSION: Synthetic reconstruction for extensor mechanism disruption shows benefit in postoperative extensor lag, graft failure, revision surgery, and cost when compared with allograft. LEVEL OF EVIDENCE: Level III.

A Retrospective Comparison of a Medial Pivot and Posterior-Stabilized Total Knee Arthroplasty With Respect to Patient-Reported and Radiographic Outcomes.

BACKGROUND: Medial pivot (MP) type total knee arthroplasty (TKA) implants are designed with a highly congruent medial tibiofemoral articulation. Compared with the cam-and-post design of the posterior-stabilized (PS) TKA, the MP-TKA design has been hypothesized to better replicate the natural kinematics of the knee. We compared the MP-TKA and PS-TKA designs, with our primary outcome measures being range of motion (ROM) and patient-reported satisfaction. METHODS: This study was a retrospective comparison between the 2 groups (76 MP-TKA vs 88 PS-TKA). ROM was collected preoperatively, 6 weeks, 6 months, and 1 year postoperatively. The Forgotten Joint Score-12 (FJS-12) scores were collected at a minimum of 1 year postoperatively. RESULTS: There was no statistically significant difference in age, gender, or body mass index between the groups. We found a statistical difference in preoperative ROM (MP = 120.3°, PS = 112.8°, P = .002). There was no difference in ΔROM at 6 weeks (MP = -12.36, PS = -3.79, P = .066), 6 months (MP = -4.23, PS = 2.73, P = .182), or 1 year (MP = .17, PS = 3.31, P = .499). Patients who underwent the MP-TKA scored significantly better than the PS-TKA on the FJS-12 score (MP = 59.72, PS = 44.77, P = .007). CONCLUSION: We found that patients who underwent the MP-TKA scored better on the FJS than those who underwent the PS-TKA; particularly with regard to deep knee flexion and stability of the prosthesis. The MP-TKA design may offer improved patient outcomes because of its highly congruent medial tibiofemoral articulation.

Patient's Height and Hip Medial Offset Are the Main Determinants of the Valgus Cut Angle During Total Knee Arthroplasty.

BACKGROUND: Valgus cut angle (VCA), defined as the angle between the anatomical and the mechanical axes of femur, is an important parameter upon which a critical step of knee arthroplasty is based. Some variables have been proposed to affect the magnitude of this cut. However, little information is available regarding whether a generic value can be used, or if a patient-specific value from a long leg X-ray, or factors that can be determined preoperatively, is necessary to accurately set the VCA. METHODS: Standard standing 3-joint views were used to measure a number of anatomical measurements in 358 limbs, 202 patients (116 women, 86 men). Neck-shaft angle, medial offset, femoral length (FL), distal femoral articular angle, and VCA were measured. Demographic data including gender and height were extracted from hospital charts. The correlation of VCA with each of the other factors was evaluated using linear regression and t-test and finally multivariate analysis. RESULTS: The average VCA was 5.76° (range 4-8). Gender and distal femoral articular angle were not related to VCA (P = .343 and .995). FL was found to be a function of height with similar effects on multivariate analysis. Only the height (or FL) and femoral offset were identified as independent factors, with a negative correlation for the former (P < .001) and a positive correlation for the latter (P < .001). CONCLUSION: Femoral offset and height are the 2 independent factors determining VCA. Other parameters are indirectly related to these 2 factors. Tall patients with a small femoral offset have smaller VCA and short patients with a large offset have larger VCA. The wide variety of VCA values does not support using a generic value for all patients during knee arthroplasty.