Revisiting the universal femoral component: Midterm outcomes of a modern design.

Introduction: Approximately 10 years ago a total knee arthroplasty system with a modern universal femoral component was introduced. It includes a symmetrical femoral and tibial component. The purpose of this study was to evaluate the 6-year clinical outcomes of this implant from a single surgeon. Materials and methods: A retrospective chart review was performed on all patients who received a TJO Klassic® Knee from January 2014 to January 2015 (Total Joint Orthopedics Inc., Salt Lake City, Utah). In total there were 131 patients (149 knees) who underwent total knee arthroplasty with this system. A retrospective chart review was performed including demographics, preoperative and postoperative clinical assessments including Knee Society score (KSS), range of motion, and radiographic assessment. Results: There were 60 males (45.8 %) and 71 females (54.2 %) with 149 knees available for review. Mean age at time of surgery was 67.4 years (45-91) and BMI was 32.6 kg/m2 (16.6-54.6). The patella was left unresurfaced in 37 knees (24.8 %), KSS scores including the clinical and functional components all improved significantly (p < 0.001). ROM improved significantly (p < 0.001). 9 knees underwent reoperation within 6 years of their index operation: 2 quadriceps tendon repairs, 3 polyethylene exchanges for laxity, 2 two-stage revisions for infection, 1 revision for aseptic loosening of the femur, and 1 for post-traumatic patella fracture. Conclusion: 6-year outcomes of a modern universal femoral design demonstrate excellent clinical results and survivorship equal to modern asymmetrical femur designs. There were no known instances of patellar maltracking.

Early Outcomes of a Universal Femoral Component with an Ultracongruent Insert.

INTRODUCTION: A primary total knee arthroplasty (TKA) system was introduced with a modern universal femoral design with a wide range of size and constraint options to accommodate a variety of patient anatomy, while incorporating streamlined instrumentation for maximum operating room efficiency and economy. The purpose of this study is to review the early clinical outcomes and survivorship at minimum two-year follow up with this knee system. MATERIALS AND METHODS: From September 2015 to December 2019, 797 patients (1004 knees) underwent primary total knee arthroplasty (TKA) at our center with the TJO Klassic® Complete Primary Knee System (Total Joint Orthopedics Inc., Salt Lake City, Utah) with ultracongruent bearings and were available for study with minimum two-year follow up. All office and hospital records were reviewed for patient demographics, preoperative and postoperative clinical assessments, including range of motion, Knee Society Scores (KSS), University of California at Los Angeles (UCLA) activity scales, complications, and reoperations. RESULTS: Mean follow up was 3.1 years (range, 2-6; standard deviation [SD] ±1.0). There were 471 female patients (59%) and 326 male patients (41%). Mean age at surgery was 69.3 years and mean body mass index was 32.9kg/m2. An all-polyethylene tibial component was used in 305 knees (30.4%) while a modular titanium tibial baseplate with polyethylene insert was used in 699 (69.6%). The patella was left unresurfaced in 381 knees (37.9%). KS scores, including pain component, clinical, and functional, as well as UCLA scores, all improved significantly (p<0.001). Two patients (3 knees) underwent revision. One patient required two-staged revision for treatment of infection in both knees, and one patient required patellar revision for aseptic loosening. Kaplan-Meier survival at 6.2 years was 98.4% (95% CI: ±0.97%) to endpoint of revision of any part for any cause and 99.6% (95% CI: ±0.36%) to endpoint of aseptic revision. CONCLUSIONS: At early minimum two-year follow up, this modern universal complete knee system used with ultracongruent bearings demonstrates excellent clinical outcomes and survival.

Midterm Outcomes and Survivorship of Anterior Stabilized Versus Cruciate Retaining Bearing in Primary Total Knee Arthroplasty.

BACKGROUND: There has been increasing utilization of ultracongruent bearings with a cruciate retaining (CR) femoral component in primary total knee arthroplasty. The purpose of this study is to compare outcomes and survivorship between an ultracongruent anterior stabilized (AS) and CR bearing. METHODS: A retrospective review was performed from 2010 through 2014 of all primary total knee arthroplasties with a single knee systems identical CR femur and AS or CR bearing with minimum 2-year follow-up yielding a study cohort of 3323 patients (4164 knees). Knee range of motion, Knee Society pain scores, Knee Society clinical scores, Knee Society functional scores, and University of California Los Angeles activity scores were evaluated. The need for manipulation under anesthesia (MUA), nonrevision surgery and revisions were assessed. RESULTS: AS bearing was used in 1471 knees (35%) and CR bearing used in 2693 knees (65%). Mean follow-up was 5.4 years. The AS group had significantly higher improvements in knee range of motion, Knee Society clinical, Knee Society functional, and Knee Society pain scores. MUAs were performed on 120 knees (8.2%) in the AS group compared with 158 knees (5.9%) in the CR group (P = .005). The AS group had significantly less all-cause failure, aseptic failures, revisions for instability, and revisions for isolated polyethylene wear. The 10-year aseptic survival for AS was 98.3% and for 92.3% for the CR group (P = .002). CONCLUSION: These mid-term results demonstrate the AS bearing had significantly higher improvements in clinical and functional outcomes as well as greater survivorship. Knees in which an AS bearing was used did have a higher incidence of MUA.

Early Outcomes of an Alternative Bearing Surface in Primary Total Knee Arthroplasty in Patients with Self-reported Metal Allergy.

BACKGROUND: Most implants for total knee arthroplasty (TKA) are comprised of alloys that contain nickel. Controversy exists whether metal allergies produce negative effects and affect clinical outcomes. The purpose of this study was to retrospectively review a minimum 2-year follow-up with an ion-bombarded titanium TKA implant in patients with reported metal sensitivity. METHODS: A retrospective review of patients who underwent primary TKA with the ion-bombarded titanium Vanguard (Zimmer Biomet, Warsaw, IN) implant with 2-year minimum follow-up was performed from 2008 through 2017. The query revealed 346 patients (451 knees) with minimum 2-year follow-up. The mean age was 64.7 years, the mean body mass index was 35.1 kg/m2, and 95% of patients were women. RESULTS: The mean follow-up was 4.6 years. The mean range of motion improved from 109° to 112° (P = .03), University of California Los Angeles activity scale from 4.1 to 5.1 (P < .001), Knee Society Clinical scores from 36 to 89 (P < .001), and Knee Society Functional scores from 48 to 73 (P < .001). There were 5 (1.1%) revisions: 2 infections (2-staged exchange), 1 tibial revision for aseptic loosening after a fall, and 2 bearing exchanges for instability. Other surgeries were open reduction internal fixation of periprosthetic fracture, 1 arthroscopic release of snapping popliteus, and 4 local wound incision and debridement (2 superficial infections and 2 nonhealing wounds). Manipulation under anesthesia was required in 27 (6%) patients. CONCLUSIONS: These early results are encouraging for the use of alternative metal titanium alloy implants in metal-sensitive patients undergoing primary TKA. At 4.6 years of mean follow-up, patients had substantial improvement in the range of motion and clinical outcomes with a low frequency of revision.

Metaphyseal Stem Extension Improves Tibial Stability in Cementless Total Knee Arthroplasty.

BACKGROUND: The goal was to determine if the addition of a metaphyseal stem extension limits micromotion of a cementless tibial component during cyclic loading in primary total knee arthroplasty. The hypothesis tested was that the use of a 50-mm stem extension on a cementless tibial component would limit motion compared with an identical cementless component without a stem extension. METHODS: The study used 3 variations of a tibial component from the same total knee arthroplasty system. Group 1 consisted of a cementless tibial component without a stem extension. Group 2 used the same cementless component as group 1, but with the addition of a short 50-mm stem. Group 3 consisted of a cemented tibial component without a stem extension to serve as a "control" (gold standard). The tibial specimens were implanted into a synthetic bone model and tested using a physiological medial-lateral 60/40 load distribution for 5000 cycles. RESULTS: The results demonstrated a significant decrease in motion at the anterior region of the cementless stem extension (group 2) components compared with the cementless with no stem extension (group 1). The cementless with stem extension (group 2) demonstrated similar results at all cycles to the cemented (group 3) components at the anterior region. CONCLUSION: The addition of a short metaphyseal stem (50mm) to a keel plus 4-peg tibial component design provides a significant reduction in micromotion during cyclic loading of a cementless tibial baseplate in a synthetic foam bone model, similar to a cemented implant.

The Feasibility of Outpatient Revision Total Knee Arthroplasty in Selected Case Scenarios.

BACKGROUND: As total knee arthroplasty (TKA) continues moving to the outpatient arena, the demand for revision surgery will subsequently increase which draws into question the feasibility for some revision scenarios as an outpatient. The purpose of this study is to report on the safety of outpatient revision knee arthroplasty. METHODS: From June 2013 through December 2018, 102 patients (106 knees) underwent revision knee arthroplasty at a free-standing ambulatory surgery center. Mean patient age was 58.0 years, and 43% of patients were male. Procedures included the following: 45 cases of unicompartmental arthroplasty to TKA, 54 TKA revisions, and 52 cases involved a full exchange of components. RESULTS: Ninety-three patients (88%) were discharged the same day without incident, none required transfer to acute facility, and 13 required overnight stay with 4 of these for convenience and 9 for medical reasons. There were no major complications within the first 48 hours postoperative. One patient required readmission for treatment of ileus 11 days postoperative. There were no other readmissions, no subsequent surgeries, and no deaths within 90 days. One or more major comorbidities were present in 66 patients. CONCLUSION: Outpatient revision knee arthroplasty was found to be safe in carefully selected patients and case scenarios. Presence of medical comorbidities was not associated with risk of complications. The paradigm changes of patient education, medical optimization, and a multimodal program to mitigate the risk of blood loss and reduce need for narcotics facilitates performing some revision arthroplasties safely in an outpatient setting.

Metal-on-Metal Total Hip Revisions: Pearls and Pitfalls.

BACKGROUND: At the turn of the 21st century, there was a re-emergence of metal-on-metal (MoM) articulation with 35% of all total hip arthroplasty implants having MoM articulation. Approximately 10 years after its peak use, MoM articulation began to decrease dramatically as revisions became more apparent because of adverse reaction to metal debris. Today, there are surveillance guidelines and reconstructive clinical pearls a surgeon should recognize. METHODS: This article gives a literature-based overview of clinical pearls and discusses how to avoid pitfalls when performing revision of a metal-on-metal total hip arthroplasty. RESULTS: Patients with MoM can be risk-stratified based on symptom, implant, and testing variables. Those patients who are symptomatic and/or develop adverse reaction to metal debris with local tissue destruction will require a revision. The revision of MoM can be challenging due to bone and soft tissue destruction. Constraint may be needed in cases of abductor deficiency. CONCLUSION: Although MoM implants for THA have declined significantly, surgeons are still faced with the revision burden from a decade of high use. Risk stratification tools are available to aid in revision decision making, and the surgeon should be prepared to address the challenges these revisions present.

Midlevel Constraint Without Stem Extensions in Primary Total Knee Arthroplasty Provides Stability Without Compromising Fixation.

BACKGROUND: Many total knee arthroplasty (TKA) systems allow for so-called midlevel constraint (MLC) articular bearings that can be used with primary implants. The purpose of this study is to report the early outcomes with MLC bearings in primary TKA. MATERIALS/METHODS: From December 2005 to June 2015, minimum 2-year follow-up was available on 96 patients (103 TKA) who underwent primary TKA with an MLC bearing using the Vanguard Total Knee System. Outcomes included pain, Knee Society clinical and functional score, range of motion, and need for revision. RESULTS: Mean follow-up was 5 years (range, 2-11 years). Range of motion improved from 103 to 113. Knee Society clinical and function scores improved from 28 and 43 to 88 and 62, respectively. There were 10 manipulations (9.9%). There were no failures for aseptic loosening of any components; however, 10% of patients were lost to follow-up. There were 3 revisions (3%): 1 patellar tendon rupture, 1 open lysis of adhesions for stiffness, and 1 2-stage treatment of infection. CONCLUSION: In cases of intraoperative medial collateral ligament incompetence, severe deformity, or valgus deformity requiring release of the lateral collateral ligament, the use of MLC showed good survivorship with no cases of aseptic loosening or instability.