Minimum 25-Year Results of a Tapered Titanium Porous Plasma Spray Coated Femoral Component.

BACKGROUND: Previous studies have reported excellent results with tapered, titanium, porous plasma-sprayed components in patients undergoing uncemented primary total hip arthroplasty (THA). The purpose of this study was to examine survival and clinical results at a minimum 25-year follow-up. METHODS: We reviewed all patients who underwent primary THA at our center through 1995 with a specific femoral component that was essentially unchanged since its 1984 introduction, except porous coating was continued circumferentially in 1987, a hydroxyapatite-coated option was offered in 1988, and an offset option was added in 1999. There were 332 patients (396 THA) who had a minimum 25-year follow-up (range, 25 to 37). Mean age at surgery was 48 years (range, 21 to 70 years). Mean follow-up in nonfailed patients was 29 years (range, 25 to 37 years). RESULTS: There were 31 femoral revisions (7.8%): 9 infections, 3 failures of ingrowth, 5 aseptic loosening, 8 osteolysis well-fixed, 2 periprosthetic fractures, 2 polyethylene wear with trochanteric avulsion, 1 component breakage, and 1 malalignment well-fixed. Kaplan-Meier survival with the endpoint of all-cause stem revision was 94.8% (95% confidence interval: ±0.9%) at 37 years, and with the endpoint of aseptic loosening/failure of ingrowth was 98.7% (95% confidence interval: ±0.5) at 37 years. Harris hip scores improved significantly from 43 preoperatively to 76 most recently. CONCLUSION: This tapered, titanium, porous plasma spray-coated femoral component continues to demonstrate high long-term survival with a low rate of femoral component revision for any reason or aseptic loosening/failure of ingrowth.

Impact of Proximal Tibial Varus Anatomy on Survivorship After Medial Unicondylar Knee Arthroplasty.

BACKGROUND: Precise indications for medial unicondylar knee arthroplasty (UKA) continue to be defined. It is unclear if patients who have proximal tibia vara should be considered candidates for UKA. The purpose of this study was to evaluate the impact of proximal tibial varus alignment on outcomes after UKA. METHODS: A retrospective review identified 2,416 patients (3,029 knees) who underwent mobile-bearing medial UKA with 2-year minimum follow-up or revision. Preoperative radiographs were evaluated, and medial proximal tibial angle (mPTA) was measured. Patients were grouped into two groups as follows: mPTA <80 degrees and mPTA ≥80 degrees. Analyses were performed on the impact of mPTA on clinical outcomes, all-cause revisions, and tibial failures. RESULTS: At a mean follow-up of 5 years (range, 0.5 years to 12.8 years), there was not a statistically significant difference in clinical outcomes nor increased risk for all-cause revision or tibial failure in patients who had an mPTA <80°. Mean mPTA in patients who had tibial failures was 82.5° and not significantly different than those who did not have a tibial failure (82.9°) (P = .289). Tibial failure rate in knees with an mPTA <80° was 2.2% and not significantly different than knees with an mPTA ≥80° at 1.4% (P = .211). The all-cause revision rate in knees with an mPTA <80° was 5.8% and was not significantly different than knees with an mPTA ≥80° at 4.9% (P = .492). CONCLUSION: Patients who have tibia vara are not at increased risk for tibial related or all-cause failure in medial UKA. This data may allow surgeons to increase their indications for medial UKA.

Custom Triflange Acetabular Components For Catastrophic Bone Loss: Minimum 5-Year Results.

INTRODUCTION: Custom acetabular components are an increasingly utilized reconstructive option in total hip arthroplasty for catastrophic bone loss and acetabular failure. The purpose of this study was to determine the survivorship of such components for reconstruction due to catastrophic bone loss at a minimum 5-year follow-up. METHODS: From August 2003 to July 2016, 64 patients (66 hips) underwent acetabular reconstruction with custom triflange components. All hips were classified as Paprosky 3B or 3C. Harris hip scores were analyzed. Overall survivorship was determined by survival analysis. RESULTS: Seventeen patients (18 hips) died prior to returning for 5-year follow-up. One presumed living patient was lost to contact, yielding a cohort of 46 patients (47 hips) who had minimum 5-year follow-up. The mean age was 65 years (range, 46 to 85), mean body mass index was 29.4 (range, 18 to 45), and 72% were women. Mean follow-up was 8 years (range, 5 to 16). There were 3 revisions of the triflange device (6.4%) due to infection. Survivorship to end point of triflange removal for any reason was 94.1% (95% confidence interval: ±3.4%) at a mean of 16 years. In the overall series (n = 66), there were 9 (13.6%) additional reoperations as follows: 5 incision and debridements, one open reduction internal fixation, two stem revisions for periprosthetic femoral fracture, and one head revision. Harris hip scores improved significantly from a mean of 41 points preoperatively to 64 points postoperatively. CONCLUSIONS: Custom acetabular triflange components represent a highly effective tool in a surgeon's armamentarium. These devices are extremely helpful in managing catastrophic bone loss and have a good mean 16-year survival.

Tough Questions in Total Hip and Total Knee Arthroplasty.

Some of today's tough questions surrounding hip and knee arthroplasty involve modifiable risks, bilateral staging, physiotherapy, postoperative activity, venous thromboembolism and infection prophylaxis, pain management, and outpatient settings. The available literature is reviewed to provide answers to difficult questions facing the orthopaedic surgeon. Preoperative questions focus on patient selection, medical optimization, and appropriateness for outpatient surgery. Modifiable risk factors for undergoing lower extremity arthroplasty include obesity, smoking, and diabetic control. Guidelines are presented to advise which patients are suitable candidates to undergo the procedure in an outpatient setting. Perioperative questions arise regarding the use of first-generation cephalosporins for prophylaxis, topical vancomycin powder, tranexamic acid, negative-pressure dressings, local intra-articular injections, and optimal timing of staged bilateral procedures. Postoperative questions are often raised about the necessity of formal postoperative physical therapy, when can patients resume driving after arthroplasty, should patients return to high-level sporting activity, and how long should patients be advised to take antibiotic prophylaxis for dental procedures.

Mid-Term Survival of Total Hip Arthroplasty in Patients Younger Than 55-year-old.

BACKGROUND: Survivorship of total hip arthroplasty (THA) in younger patients is concerning given the inverse relationship between age and lifetime risk for revision. The purpose of this study is to determine if risk of revision has improved for patients aged 55 years or younger who undergo primary THA using modern polyethylene liners. METHODS: A retrospective review identified 2,461 consented patients (2,814 hips) with minimum 2-year follow-up who underwent primary THA at our institution between September 2007 and August 2014 using components from a single manufacturer (Zimmer Biomet), all with vitamin E-infused highly crosslinked polyethylene acetabular inserts. There were 561 patients (643 THA; 23%) aged 55 or younger and 1,900 (2,171 THA; 77%) older than 55. RESULTS: Mean follow-up was 5.0 years for both groups. There were more male patients in the younger (55%) than older (41%) group. Body mass index (BMI) was higher in younger patients independent of gender. Improvement in Harris hip score (HHS) was similar between groups. Kaplan-Meier survival to endpoint of all cause revision was similar between groups at 12 years (P = .8808) with 97.5% (95% CI: ±0.7%) for younger versus 97.1% (95% CI: ±0.6%) for older patients. Most frequent reason for revision overall was periprosthetic femoral fracture (21; 0.75%); univariate analysis revealed risk factors were female gender (P = .28) and age ≥65 years (P = .012). CONCLUSION: Use of modern polyethylene, such as vitamin E-stabilized highly cross-linked, liners during THA may improve survivorship in younger patients undergoing THA. Younger patients undergoing primary THA with highly cross-linked polyethylene liners had no increased rate of revision at mid-term follow-up.

Survivorship of a Metal-on-Metal Total Hip Implant With Modular Titanium Adapter.

BACKGROUND: Use of metal-on-metal (MoM) articulations in total hip arthroplasty (THA) has sharply declined due to high failure rates from metal-related complications. Although certain MoM designs have demonstrated only 46% survival, not all MoM designs have performed the same. The purpose of this study is to evaluate mid-term to long-term survival of a specific MoM implant with a modular titanium taper adapter. METHODS: A retrospective review was performed on all patients who underwent primary THA at our center with the M2a-Magnum system (Zimmer Biomet, Warsaw, IN). Of 829 patients (956 hips) identified, 754 patients (869 hips) met inclusion criteria of signed research consent, minimum 2-year follow-up, and/or any revision surgery. RESULTS: Mean follow-up was 11.0 years (range 2-16; ±3.5). Mean cup angle of inclination was 42.8° (range 24°-70°, ±6.3°), with 88.0% reconstructed within the 40° ± 10° safe zone. There were 64 revisions (7.36%): 7 (0.81%) septic and 57 (6.56%) aseptic. Of those, 32 (3.68%) were adverse reactions to metal debris. Kaplan-Meier survival free of revision for all causes was 88.6% at 16 years (95% confidence interval 86.8-90.4). Univariate analysis of risk factors for all-cause, aseptic, and adverse reaction to metal debris revision found no relationship with female gender, age ≥65 years, body mass index >30 kg/m2, higher activity level, or inclination angle outlier. CONCLUSION: The results of this study demonstrate a more favorable mid-term to long-term survivorship with this specific MoM implant compared to other designs. Although our institution no longer performs MoM THA, further investigation into differences in MoM implant designs is warranted.

Impact of perivascular lymphocytic infiltration in aseptic total knee revision.

AIMS: A limited number of investigations with conflicting results have described perivascular lymphocytic infiltration (PVLI) in the setting of total knee arthroplasty (TKA). The purpose of this study was to determine if PVLI found in TKAs at the time of aseptic revision surgery was associated with worse clinical outcomes and survivorship. METHODS: A retrospective review was conducted on 617 patients who underwent aseptic TKA revision who had histological analysis for PVLI at the time of surgery. Clinical and radiological data were obtained pre- and postoperatively, six weeks postoperatively, and then every year thereafter. RESULTS: Within this cohort, 118 patients (19.1%) were found to have PVLI on histological analysis. Re-revision was performed on 83 patients (13.4%) with no significant differences in all-cause or aseptic revisions between groups. A higher incidence of PVLI was noted in female patients (p = 0.037). There was no significant difference in improvement in the range of motion (p = 0.536), or improvement of KSC (p = 0.66), KSP (p = 0.61), or KSF (p = 0.3) clinical outcome scores between PVLI and no PVLI sub-groups. There was a higher incidence of a preoperative diagnosis of pain in the PVLI group compared with patients without PVLI (p = 0.002) present. CONCLUSION: PVLI found on large-scale histological analysis in TKAs at aseptic revision surgery was not associated with worse clinical outcomes or rates of re-revision. Cite this article: Bone Joint J 2021;103-B(6 Supple A):145-149.

Mid-Term Clinical Outcomes and Survivorship of a Second-Generation Modular Revision Knee System.

INTRODUCTION: Revision knee systems have adapted to the challenges of revision knee arthroplasty with offset stems, augments, cones, and various levels of constraint. The purpose of this study is to review the mid-term outcomes of a second-generation modular knee revision system. MATERIALS AND METHODS: A retrospective review was conducted from 2011 through 2014 on all patients who underwent knee arthroplasty with the Vanguard® 360 revision knee system (Zimmer Biomet, Warsaw, Indiana). Patients were included in the study if they were eligible for five-year minimum follow up and had signed a general research consent. The initial query revealed 253 patients (267 knees) that met inclusion criteria. Complications assessed were manipulation under anesthesia (MUA) and revision of any component. Statistical analysis using paired t-test was performed to evaluate changes in clinical outcomes and Kaplan-Meier survival analysis. RESULTS: Mean follow up was 6.6 years. The Vanguard® 360 knee system was used in four (1.5%) primary total knee arthroplasties (TKAs), 66 (24.7%) second-stage reimplantation TKAs after infection, and 197 (73.8%) aseptic revisions. There were significant improvements in knee range of motion and Knee Society Scores (all p<0.05). Manipulations under anesthesia were performed in 17 knees (6.4%). A total of 41 knees (15.4%) failed for any cause and required re-revision surgery. Of these, 11 (4.1%) failed due to aseptic loosening. Kaplan-Meier analysis revealed overall survival to endpoint of aseptic loosening to be 96.4% (95% CI: ±1.2%) at five years and 95.2% (95% CI: ±1.4%) at 9.5 years. When comparing survivorship in patients who underwent initial revision for aseptic indications compared with those whose underwent revision for second-stage reimplantation after infection, Kaplan-Meier survival to endpoint of revision for any cause at 9.5 years was higher for patients with aseptic than septic indication for TKA (87.0% [95% CI: ±2.4%] vs. 75.3% [95% CI: ±5.4%], p=0.0156). CONCLUSION: The findings of this study demonstrate greater than 95% aseptic survivorship with the use of the Vanguard® revision knee system at mid-term follow up.

Manipulation under Anesthesia after Knee Arthroplasty Is Associated with Worse Long-Term Clinical Outcomes and Survivorship.

The literature is mixed on the long-term fate of knees that undergo manipulation under anesthesia (MUA). The purpose of this study is to evaluate the long-term outcomes and survivorship of patients who required a MUA after primary total knee arthroplasty (TKA) compared with a cohort of patients who did not undergo a MUA. Between 2003 and 2007, 2,193 patients (2,783 knees) underwent primary TKA with 2-year minimum follow-up; 182 knees (6.5%) had a MUA. Patients who had a manipulation were younger (p < 0.001) and had worse preoperative range of motion (ROM) (p < 0.001). Postoperative ROM, Knee Society clinical (KSC), functional, and pain (KSP) scores, revisions, and survivorship were compared between MUA and no MUA. Mean follow-up was 9.7 years. MUA patients had lower postoperative ROM (p < 0.001), change in ROM (p < 0.001), KSC (p < 0.001), KSP (p < 0.001), and change in KSP scores (0.013). Revisions occurred in 18 knees (9.9%) in the MUA group compared with 77 knees (3%) without a MUA (p < 0.001). Most common reason for revision after MUA was continued stiffness (50%). Relative risk for revision after one MUA was 2.01 (95% confidence interval [CI], 1.1-3.8, p < 0.001) and after three or more MUAs were 27.02 (95% CI, 16.5-44.1, p < 0.001). Ten-year survival after MUA was 89.4% (95% CI, 87.1-91.7%) compared with 97.2% (95% CI, 96.9-97.5%) without a MUA (p < 0.001). Patients who undergo a MUA after primary TKA may have a knee at risk with higher revision rates, worse long-term clinical scores, ROM and survivorship.

The feasibility of outpatient conversion and revision hip arthroplasty in selected patients.

BACKGROUND: Total hip arthroplasty (THA) continues moving to the outpatient arena, and may be feasible for some conversion and revision scenarios. Controversy surrounds appropriate patient selection. The purpose of this study is to report complications associated with outpatient revision and conversion THA, and to determine if comorbidities are associated with complications or overnight stay. METHODS: From June 2013 through August 2018, 46 patients (47 hips) underwent conversion (n = 10) or revision (n = 37) THA at a free-standing ambulatory surgery centre. This represented only 6.3% of revision THA cases at our institution during the study period that were selected for outpatient surgery. Mean patient age was 58.0 years, and 52% of patients were males. 1 or more major comorbidities were present in 15 patients (32%) including 1 valvular disease, 7 arrhythmia, 2 thromboembolism history, 3 obstructive sleep apnoea, 3 chronic obstructive pulmonary disease, 2 asthma, 4 frequent urination, and 1 renal disease. RESULTS: 44 (94%) patients were discharged same day without incident, none required transfer to acute facility, and 3 stayed overnight (2 convenience, 1 for medical reasons - urinary retention). The patient kept overnight for medical reasons had no major comorbidities. 3 patients were placed on an extended course of antibiotics, including 2 with positive intraoperative cultures and 1 for cellulitis. There were no major complications, readmissions, or subsequent surgeries within 90 days. CONCLUSIONS: Outpatient revision hip arthroplasty is safe in selected patients undergoing minor or partial revisions. Presence of medical comorbidities was not associated with risk of complications. Medical optimisation and a multimodal programme to mitigate risk of blood loss and reduce narcotic need facilitate the safe performance of arthroplasty in an outpatient setting.

Interval Between Staged Bilateral Total Knee Arthroplasties Does Not Affect Early Medical or Surgical Complications.

BACKGROUND: The purpose of this study is to evaluate early postoperative surgical and medical complications in patients undergoing staged bilateral total knee arthroplasty (TKA) and determine if the interval to the second stage influences the risk of complications. METHODS: A retrospective review was performed from 2016 through 2018 of all staged bilateral primary TKA procedures, yielding a cohort of 1005 patients (2010 TKAs). Four groups were created based on the timing of the second stage: 3 to 6 weeks, 7 to 12 weeks, 13 to 24 weeks, and >24 weeks. Clinical data compared between groups included demographics, knee range of motion, University of California, Los Angeles (UCLA) activity score, Knee Society pain score, Knee Society clinical score, and Knee Society functional score. Postoperative complications within 90 days were evaluated, with complications after the second knee being the primary outcome. RESULTS: The mean follow-up after second stage was 10.7 months (range, 3 to 37 months). No significant differences were found between groups in the range of motion, Knee Society pain, Knee Society clinical score, Knee Society functional score, or University of California Los Angeles activity score in either the first or second knee. After the first knee surgery, medical complications were highest in the >24-week group. After the second knee, there were no significant difference in manipulation (P = .9), wound complications (P = .7), venous thromboembolism (P = .8), or other medical complications (P = 1) based on the interval duration. CONCLUSION: The interval between staged TKA did not affect early medical or surgical complications after the second stage. Early clinical and function results were not different based on timing of the second surgery.

Long-Term Outcomes of a Modular System in Revision Total Knee Arthroplasty.

INTRODUCTION: With the growing demand for total knee arthroplasty (TKA), the burden of revision surgery will continue to rise. Revision knee arthroplasty has historically had worse survivorship than primary knee arthroplasty. The purpose of this study is to review the 10-year outcomes and survivorship of a modular revision knee system. MATERIALS AND METHODS: A retrospective review was conducted on 109 patients (117 knees) who underwent a revision knee arthroplasty with the Vanguard® Super Stabilized Knee (SSK) Revision System (Zimmer Biomet; Warsaw, Indiana) who were eligible for 10-year minimum follow up. Clinical and radiographic data was obtained pre- and postoperatively, six weeks postoperatively, and then every year thereafter. RESULTS: With an average follow up of 10.7 years (range, 2.3 to 14.1 years), the SSK revision system exhibited a notable improvement in both clinical and functional outcomes. Average knee range of motion improvement was 4.2 degrees (SD ±18). Manipulations under anesthesia were performed in six knees (5%). Re-revisions occurred in 27 knees (23%). Ten of the re-revisions were for aseptic loosening (37%), eight for periprosthetic infection (30%), five for instability (19%), and the remainder for other aseptic causes. Mean time to failure was 4.6 years (range, 1 to 9.1 years). The 10-year all-cause survival was 77% (95% confidence interval [CI], 73 to 81%). The 10-year aseptic survival was 83% (95% CI, 79 to 87%). CONCLUSION: The findings of this study show an 83% 10-year aseptic survivorship with the Vanguard® SSK knee revision system. These results are comparable to long-term follow up of other revision knee systems.

Isolated RingLoc Polyethylene Liner Revision for Treatment of Liner Wear.

Polyethylene wear and osteolysis has long been an issue with the survivorship of total hip arthroplasty. The purpose of this study was to assess the survivorship after isolated liner exchange with the use of the RingLoc acetabular cup. A query of our practice registry revealed 106 patients (112 hips) with a single cementless titanium plasma sprayed acetabular component (RingLoc, Zimmer Biomet, Warsaw, IN), who underwent acetabular liner exchange for treatment of polyethylene wear between January 2001 and March 2015. Eighty patients (85 hips) met inclusion criteria. Clinical outcomes were assessed with the Harris hip score and radiographic evaluation was performed. The mean follow-up after liner exchange was 6 years (range, 2-15.7 years). Harris hip scores improved from 70.9 (range, 28-100) preoperatively to 79 (range, 29-100) at most recent evaluation (p < 0.001). Subsequent surgery was required in 11 patients (11 hips, 13%). Components were revised in 7 hips (8.2%). One acetabular revision was performed for aseptic loosening and four for instability (4.7%). One metal-polyethylene sandwich liner was revised for metal hypersensitivity. One patient underwent two-staged exchange for infection. In our early to mid-term experience with the RingLoc acetabular cup, isolated liner exchange for treatment of polyethylene wear yielded 98.8% acetabular survival for aseptic loosening at up to 15 years. (Journal of Surgical Orthopaedic Advances 29(2):59-64, 2020).

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.

Higher Activity Level Following Total Knee Arthroplasty Is Not Deleterious to Mid-Term Implant Survivorship.

BACKGROUND: The impact of a patient's activity level following total knee arthroplasty (TKA) remains controversial, with some surgeons concerned about increased polyethylene wear, aseptic loosening, and revisions. The purpose of this study is to report on implant survivorship and outcomes of high activity patients compared to low activity patients after TKA. METHODS: A retrospective review identified 1611 patients (2038 knees) that underwent TKA with 5-year minimum follow-up. Patients were divided in 2 groups based on their University of California Los Angeles (UCLA) activity level: low activity (LA) (UCLA ≤5) and high activity (HA) (UCLA ≥6). Outcomes included range of motion, Knee Society scores, complications, and reoperations. Parametric survival analysis was performed to evaluate the significance of activity level on survivorship while controlling for age, gender, preoperative pain, Knee Society clinical scores, Knee Society functional scores, and body mass index (BMI). RESULTS: Mean follow-up was 11.4 years (range 5.1-15.9). The LA group had significantly more female patients, were older, had higher BMI, and had lower functional scores preoperatively (all with P < .001). The HA group had significantly higher improvements in Knee Society scores (P < .001) and pain postoperatively (P < .001). Revisions were performed in 4% of the LA group and 1.7% knees of the HA group (P = .003). After controlling for age, gender, preoperative pain, Knee Society clinical scores, Knee Society functional scores, and BMI, a higher postoperative activity level remained a significant factor for improved survivorship with an odds ratio of 2.4 (95% confidence interval 1.2-4.7, P = .011). The all-cause 12-year survivorship was 98% for the HA group and 95.3% for the LA group (P = .003). The aseptic 12-year survivorship was 98.4% for the HA group and 96.3% for the LA group (P = .02). CONCLUSION: Highly active patients had increased survivorship at 5-year minimum follow-up compared to lower activity patients after TKA. Patient activity level after TKA may not need to be limited with modern implants.

Low complication rates in outpatient total knee arthroplasty.

PURPOSE: The primary purpose of this study is to report the incidence of complications associated with outpatient total knee arthroplasty (TKA). Secondarily, 2-year minimum outcomes are reported. METHODS: Between 2013 and 2016, 928 patients underwent 1143 outpatient TKAs with the Vanguard Complete Knee System (Zimmer Biomet, Warsaw, IN). Patients were selected for outpatient surgery if they were medically optimized without a failing organ system and had sufficient support at home. Overnight stays, medical complications and early perioperative complications were assessed in this entire cohort. Two-year minimum follow-up was available on 793 patients (978 knees). Patient records were analyzed for outcome measures and revisions. RESULTS: In 124 procedures, the patient stayed overnight for 23-h observation. Thirty-seven (3.2%) were for convenience reasons and 87 (7.6%) for medical observation. Heart disease and chronic obstructive pulmonary disease were associated with increased risk of overnight stay. Excluding manipulations, reoperation within 90 days occurred in eight (0.7%) knees. Patients with 2-year minimum follow-up had significant improvements in ROM, Knee Society Clinical, Functional and Pain scores (p < 0.005). Nine (0.8%) patients required revision. Manipulations were performed on 118 (10.3%) patients. The overall deep infection rate was 0.17% (2/1143). CONCLUSIONS: Outpatient TKA is safe for a large proportion of patients. Certain medical co-morbidities increase the risk of overnight stay. Patients had significant improvement in ROM and outcome scores with low revision rate. LEVEL OF EVIDENCE: III.

Mid-Term Survivorship of a Novel Constrained Acetabular Device.

BACKGROUND: Recurrent instability after total hip arthroplasty is a difficult complication. In certain cases, a constrained acetabular device is needed to address these issues. The purpose of this study is to report the midterm outcomes and survivorship of a single novel constrained liner device. METHODS: A retrospective review as performed on all procedures (except first stage exchange for infection) in which a Freedom Constrained (Zimmer Biomet, Warsaw, IN) liner was used between December 2003 and November 2016. Patients with 2-year minimum follow-up or failure were included, yielding a cohort of 177 patients. Procedures were 130 aseptic revisions, 40 reimplantations following infection eradication, and 7 complex primaries. The constrained mechanism was implanted in 46 hips (26%) to treat active instability and 131 hips (74%) for increased risk of instability and intraoperative instability. Patients had on average 3.4 previous surgeries. RESULTS: With an average 7.1-year follow-up, 11 hips dislocated (6.2%), and 13 hips (7.3%) were revised for acetabular aseptic loosening, resulting in an overall constrained aseptic or mechanical failure rate of 13.6%. Nineteen hips (10.7%) failed from infection with 58% of these having had a previous infection. Patients with active instability had significantly higher failure for dislocation than patients who were at risk (15.2% vs 3%, P = .01). All-cause survival rate at 7 years was 74.8%, aseptic survival was 83.6%, and survival for instability was 91.8%. CONCLUSION: Revision for instability remains challenging as many patients have had numerous previous surgeries and at-risk anatomy. Constrained inserts are one option to manage instability, but a high rate of recurrence can still occur.

Partial 2-Stage Exchange for Infected Total Hip Arthroplasty: An Updated Report.

BACKGROUND: Management of an infected total hip arthroplasty (THA) is challenging. The eradication of infection as well as complications of component removal must all be considered. This study is an update on previous reports of treating periprosthetic infection of the hip with a partial 2-stage exchange with retention of the femoral component. METHODS: A retrospective review of our practice's arthroplasty registry from 2000 to 2018 revealed 41 hips with 2-year minimum follow-up that were treated with a 2-stage partial exchange for an infected THA. All first-stage procedures allowed an articulating construct with 1 of 3 variations: cemented constrained liner (13 hips), StageOne Hip Cement Spacer Mold (14 hips), or an antibiotic polymethylmethacrylate head molded from a bulb syringe (14 hips). Of 41 cases, 34 were culture positive, with 3 cases having methicillin-resistant Staphylococcus. RESULTS: Mean follow-up was 5.5 years (range, 1.5-18.5 years). The second-stage reimplantation was accomplished in 39 of the 41 hips (95%) at a mean interval of 9.2 weeks (range, 5-9 weeks). Two patients underwent repeat radical debridement with removal of all components before reimplantation for persistent clinical evidence of infection. Thirty-three of the 41 hips (81%) were infection free at most recent follow-up. The mean postoperative Harris hip score at most recent evaluation was 63.6 (range, 24-100). CONCLUSION: Eradication of periprosthetic joint infections, while minimizing patient morbidity, continues to be a challenge. Partial 2-stage exchange may be considered in cases where removal of a well-fixed femoral component may result in significant bony destruction.

Revision of Failed Metal-on-Metal Total Hip Arthroplasty: Midterm Outcomes of 203 Consecutive Cases.

BACKGROUND: Metal-on-metal (MoM) revisions have shown high rates of complications from aseptic loosening, deep infection, and dislocation. The purpose of this study is to report on outcomes and complications of a large consecutive series of patients who were revised for failed MoM total hip arthroplasty (THA). METHODS: We evaluated 188 patients (203 hips) who underwent revisions of failed MoM THA. Mean age at the revision was 60 years old. Gender was female in 112 hips (55%) and male in 91 hips (45%). Mean interval to failure after primary THA was 4.9 years (range, 0-18 years). The acetabular component was revised in 183 cases (92%). Clinical outcomes assessed included pain score and Harris hip score. RESULTS: Mean follow-up from revision was 4.2 years. Harris hip score improved from 53.6 pre-revision to 73.5 at most recent follow-up (P < .001). Pain level significantly improved from 17.2 pre-revision to 32.8 post-revision (P < .001). Reoperations occurred in 28 (14%) hips. Re-revision was required in 16 hips (7.9%). The most common reasons for re-revision were aseptic loosening (5), dislocation (3), infection (2), and iliopsoas tendonitis (2). Re-revision was significantly higher in cases of pseudotumor. There was no difference in survival with ultraporous cups. Three hips required re-revision to custom triflange components. All-cause survival was 90.5% at 4.2 years. Metal ion levels significantly declined after revision. CONCLUSION: Revisions of failed MoM THA showed improvements in clinical outcomes, but present significant surgical challenges and complications especially in cases with soft tissue damage and pseudotumor.