Cementless Total Knee Arthroplasty: Does Age Affect Survivorship and Outcomes?

BACKGROUND: Despite the growing popularity of cementless total knee arthroplasty (TKA) in younger patients, the outcomes are unclear in the elderly population. We aimed to compare the clinical outcomes and survivorship of cementless TKA between different age groups. METHODS: Utilizing our prospectively collected institutional database, we retrospectively reviewed all patients undergoing primary cementless TKAs at a tertiary care institute. We identified 347 TKA, which were divided into 3 groups based on age at the time of surgery. Group A was ≤ 60 years, Group B was 60 to ≤ 70 years, and Group C was > 70 years. We compared clinical outcomes (Knee Society Clinical Rating System [KSCRS], Western Ontario and McMaster University Osteoarthritis Index [WOMAC], and Veterans Rand 12 Item Health Survey [VR-12]) and survivorship between the groups. RESULTS: At final follow-up, range of motion, KSCRS, WOMAC, and VR-12 physical score were comparable (P > .05). The VR-12 Mental score was higher in Group B and Group C than in Group A (P = .003). Compared to preoperative scores, the change in KSCRS, WOMAC, and VR-12 physical and mental scores was comparable at the final follow-up (P > .05). No patient underwent revision for aseptic loosening. CONCLUSIONS: There were no cases of revision surgery for aseptic loosening in our cohort of 347 cementless TKAs. Patients > 70 years of age undergoing cementless TKA can achieve clinical scores equivalent to those of younger patients at short term (2-year) follow-up. Longer-term survivorship is still required, but based on early data, cementless TKA can be a safe option for older patients.

Minimum 2-Year Outcomes of a Modern Monoblock Titanium Fluted Tapered Revision Stem for Complex Primary and Revision Total Hip Arthroplasty.

BACKGROUND: Modular titanium fluted tapered (TFT) stems have demonstrated excellent clinical success for femoral revision total hip arthroplasty (THA) surgery. This study reports the short-term outcomes of a novel modern monoblock TFT stem used for revision and complex primary THA with a minimum of 2 years of follow-up. METHODS: We identified 126 patients who received a single monoblock TFT stem: 26 patients for complex THA (failed fracture fixation) and 100 patients for revision THA. The reasons for revision THA included 40 for previous periprosthetic joint infection, 42 for aseptic loosening, 9 for trunnionosis, and 9 for periprosthetic fractures. The Paprosky grading for femoral bone loss at the time of surgery and the measured subsidence of femoral stems at 3-month follow-up were determined. We evaluated the number and indications for reoperations. RESULTS: The mean time from surgery was 3.9 years (range, 2.0 to 6.9). A paired t-test analysis showed significant improvement from preoperative versus postoperative clinical outcome scores (P < .001) for Harris Hip Score (38.76 ± 15.24 versus 83.42 ± 15.38), Western Ontario and McMaster Universities Arthritis Index (45.6 ± 19.0 versus 69.9 ± 21.3), Veterans RAND 12 Item Health Survey Physical component (31.7 ± 8.1 versus 37.8 ± 11.3), and Veterans RAND 12 Item Health Survey Mental component (48.2 ± 12.2 versus 51.6 ± 12.5). The Paprosky grading for femoral bone loss was Grade 1 (3.9%), Grade 2 (35.7%), Grade 3A (47.6%), Grade 3B (11.1%), and Grade 4 (1.6%) cases. There were 18 reoperations (14.7%), with 13 for periprosthetic joint infection (7 treated with implant retention and 6 treated with a 2-stage revision), 4 for instability, and 1 for acetabular aseptic loosening. There were no aseptic failures of the stem. CONCLUSIONS: This novel modern monoblock TFT stem provided reliable femoral fixation and has increasingly supplanted the use of modular TFT stems for complex primary and revision surgery in our institution.

Effect of Surgical Technique, Implant Design, and Time of Examination on Contact Kinematics: A Study of Bicruciate-Stabilized and Posterior-Stabilized Total Knee Arthroplasty.

BACKGROUND: Bicruciate-stabilized (BCS) total knee arthroplasty (TKA) designs attempt to approximate natural knee mechanics. Multiple surgical techniques, including gap balancing (GB) and measured resection (MR), have been developed to provide optimal implant positioning and soft-tissue balance. The goal of this study was to determine the effect of surgical technique on BCS TKA contact kinematics. Secondary goals included investigating the change of kinematics over time and comparing BCS TKA kinematics to a posterior-stabilized (PS) design. METHODS: The study included the BCS-GB, BCS-MR, and PS-MR groups. The BCS-GB and BCS-MR groups underwent weight-bearing radiostereometric analysis for multiple knee flexion angles at 3 months and 1 year postoperatively, whereas the PS-MR group was imaged at 1 year postoperatively. The medial and lateral contact kinematics were determined from implant poses. RESULTS: There were no differences in BCS TKA kinematics between the GB and MR techniques. There were differences in the mid-flexion ranges when comparing the 3-month and 1-year kinematics of the BCS design; however, they were less than 1.5 mm. Differences existed between the kinematics of the BCS and PS designs at all flexion angles for the medial condyle (P < .0006) and at 0° of flexion on the lateral condyle (P < .0001). CONCLUSIONS: Contact kinematics for a BCS design were similar for both surgical techniques, suggesting both are appropriate for this design. Small, likely clinically insignificant differences were found between 3-month and 1-year kinematics. The BCS TKA kinematics differed from the PS design; however, it is unclear whether these differences improve clinical outcomes.

Survivorship and Outcomes of 2-Stage Revision for Infected Total Hip Arthroplasty at a Mean of 7-Year Follow-Up.

BACKGROUND: Periprosthetic joint infection (PJI) continues to be one of the leading causes of failure following total hip arthroplasty (THA). The objectives of the study were to (1) determine the minimum 2-year infection-free survivorship of 2-stage revision THA, (2) determine the causative organisms for repeat 2-stage revision THA, and (3) characterize the results of failed 2-stage revisions and evaluate patient-reported outcome measures (PROMs). METHODS: A retrospective chart review was completed for patients who underwent 2-stage revision THA for PJI. Prospective data were collected on each patient, including demographics, causative organisms, complications, and type of reoperation. The PROMs, including Harris Hip Score, 12-item Short-Form Health Survey, and Western Ontario and McMaster Universities Osteoarthritis Index scores were obtained prior to 2-stage revision THA surgery and annually as part of standard clinical and radiographic follow-up. RESULTS: A total of 328 patients who underwent a 2-stage revision THA for a PJI were included in the study (mean age 67 years [range, 28 to 90], mean body mass index of 30.6 [range, 15 to 57]). The overall infection-free survivorship for 2-stage revision THA was 73.8% at a minimum of 2 years (range, 2 to 20). Overall, 194 (59.1%) patients who had successful infection eradication underwent a 2-revision THA only. The most common single organisms infected were Staphylococcus aureus (12.5%) and Staphylococcus epidermidis (11%). Higher reoperation rates were found in cases with methicillin-resistant Staphylococcus aureus and polymicrobial infections. All PROMs showed statistical improvement from preoperatively to the latest follow-up appointment. CONCLUSIONS: Two-stage revision THA is associated with a good success rate in the treatment of PJIs at mid-term to long-term follow-up. Polymicrobial and methicillin-resistant Staphylococcus aureus infections are poor prognostic factors, making the eradication of infection more difficult. The management of PJIs continues to be one of the most important orthopaedic challenges to treat.

Predictors of Undergoing Revision Within 5 Years of Total Knee Arthroplasty: A Population-Based Study.

BACKGROUND: The objective of this study was to identify the rate and risk factors for revision total knee arthroplasty (TKA) within the first 5 years postoperative. Our secondary objective was to identify the rate of additional surgical procedures and death. METHODS: We conducted a retrospective cohort study among patients in Ontario, Canada who underwent an elective, primary TKA between April 1, 2007, and March 31, 2014, for osteoarthritis. We excluded patients under 40 years and who had undergone a TKA within the previous 15 years. Our final study cohort included 94,193 patients. We reported the proportion of the study cohort who experienced revision surgery within 2 and 5 years of the primary TKA; secondary surgery within 5 years. We conducted Cochran-Armitage tests for trends to assess changes in the proportion of patients who experienced each of the study outcomes, and multivariable logistic regressions to evaluate predictors of a revision TKA. RESULTS: There were 3,112 (3.3%) patients who had a revision within 5 years, and 1,866 (2.0%) within 2 years of their primary TKA. 3,316 (3.5%) had a secondary surgery (0.6% patellar resurfacing; 1.6% manipulation; 1.3% synovectomy; 0.5% washout; 0.9% debridement). Lower age, men, lower income, higher comorbidity score, depression, previous arthroscopy, lower surgeon volume, and general anesthesia were all significant positive predictors of revision. CONCLUSIONS: In our study cohort, 2.0% of patients had a revision TKA within 2 years, and 3.3% within 5 years of their primary TKA. Preoperative identification of risk factors may reduce the future prevalence of revision TKAs.

Axial and Sagittal Rotation of Cementless Tibial Baseplates Occurs in Bone Under Joint Loading.

BACKGROUND: There has been a recent increase in the use of cementless fixation for primary total knee arthroplasty. While the early results of contemporary cementless implants are promising, understanding the behavior of cementless tibial baseplates under loading remains an ongoing interest. The objective of this study was to identify the pattern of displacement that occurred under loading for a single cementless tibial baseplate design at one year post operation for stable and continuously migrating implants. METHODS: There were 28 subjects from a previous trial of a pegged highly porous cementless tibial baseplate evaluated. Subjects underwent supine radiostereometric exams from two weeks through one year after surgery. At one year, subjects also underwent a standing radiostereometric exam. Fictive points on the tibial baseplate model were used to relate translations to anatomical locations. Migration over time was calculated to determine if subjects displayed stable or continuous migration. The magnitude of inducible displacement between the supine and standing exams was calculated. RESULTS: Inducible displacement patterns were similar between stable and continuously migrating tibial baseplates. Displacements were greatest in the anterior-posterior axis followed by the lateral-medial axis. Correlation of displacements between adjacent fictive points in these axes indicated an axial rotation of the baseplate occurred under loading (r2 = 0.689-0.977, P < .001). Less displacement occurred in the superior-inferior axis and correlations indicated an anterior-posterior tilt of the baseplate occurred under loading (r2 = 0.178-0.226, P = .009-.023). DISCUSSION: From supine to standing position the predominant pattern of displacement for this cementless tibial baseplate was axial rotation, with some subjects also displaying an anterior-posterior tilt.

Correlating Contact Kinematics to Tibial Component Migration Following Cemented Bicruciate Stabilized Total Knee Arthroplasty.

BACKGROUND: Contact kinematics in total knee arthroplasty (TKA) has been shown to affect tibial component migration. However, previous studies correlating kinematic variables to implant migration were completed with older TKA designs. The goal of this study was to determine if there are associations between contact kinematics and tibial component migration for a cemented, bicruciate stabilized (BCS) TKA system. METHODS: A total of 54 knees implanted with a BCS TKA system were analyzed using radiostereometric analysis (RSA). Patients underwent RSA exams at 2 weeks, 6 weeks, 3 months, 6 months, 1 year, and 2 years post operation to measure tibial component migration. At 1 year, contact kinematics was evaluated during a quasi-static deep knee bend. Linear regression analyses were performed between kinematic variables and migration values. RESULTS: Significant correlations were found between contact kinematics and tibial component migration. Excursion on the lateral condyle was the most consistent variable correlating with implant migration. Six patients had > 0.2 mm migrations from 1 to 2 years post operation indicating continuously migrating tibial components, and most had atypical contact kinematics. CONCLUSION: Kinematics was shown to influence tibial component migration. Reduced lateral excursion, suggesting a more constrained lateral condyle, resulted in greater implant migration. The 6 patients who had continuously migrating tibial components had demographic factors that may limit the ability to endure unintended force transmissions caused by abnormal kinematics. These results highlight the importance of restoring knee kinematics with this BCS TKA design to minimize improper force transmissions and resultant increased implant migrations.

Extensively Porous-Coated Stems Demonstrate Excellent Long-Term Survivorship in Revision Total Hip Arthroplasty.

BACKGROUND: Extensively porous-coated cylindrical stems have demonstrated excellent results in revision total hip arthroplasties (THAs). However, most studies are midterm follow-ups and of modest cohort size. This study aimed to evaluate long-term outcomes of a large series of extensively porous-coated stems. METHODS: From 1992 to 2003, 925 extensively porous-coated stems were utilized in revision THAs at a single institution. The mean age was 65 years, and 57% of patients were males. Harris hip scores were calculated, and clinical outcomes were assessed. Radiographic assessment for stem fixation was categorized as either in-grown, fibrous stable, or loose according to Engh criteria. Risk analysis used Cox proportional hazard method. The mean follow-up was 13 years. RESULTS: Mean Harris hip scores improved from 56 to 80 at the last follow-up (P < .001). Fifty-three femoral stems (5%) were rerevised: 26 for aseptic loosening, 11 for stem fractures, 8 for infection, 5 for periprosthetic femoral fractures, and 3 for dislocation. Cumulative incidence of aseptic femoral loosening and femoral rerevision for any reason were 3% and 6.4% at 20 years, respectively. Nine of eleven stem fractures occurred with 10.5-13.5 mm diameters (mean 6 years). Radiographic review of unrevized stems demonstrated 94% bone-ingrown. Demographics, femoral bone loss, stem diameter, and length were not predictors of femoral rerevision. CONCLUSION: In this large series of revision THAs using a single extensively porous-coated stem design, the cumulative incidence of rerevision for aseptic femoral loosening was 3% at 20 years. These data confirm the durability of this stem in femoral revision, providing a long-term benchmark for newer uncemented revision stems. LEVEL OF EVIDENCE: Level IV, retrospective study.

No Difference in Subsidence Between Modern Monoblock and Modular Titanium Fluted Tapered Femoral Stems.

BACKGROUND: Subsidence remains a concern when utilizing tapered fluted titanium (TFT) femoral stems and may lead to leg length discrepancy, impingement, instability, and failure to obtain osseointegration. This study aims to compare stem subsidence across 3 modern TFT stems. Our secondary aim was to investigate the influence of bicortical contact or "scratch fit" on subsidence, as well as the role of intraoperative imaging in maximizing bicortical contact and preventing stem subsidence. METHODS: A retrospective review of 271 hip arthroplasties utilizing modern TFT stems at a single institution was performed. Three stem designs were included in the analysis: 1 monoblock TFT stem (n = 91) and 2 modular TFT stems (n = 90; n = 90). Patient demographics, Paprosky femoral bone loss classification, bicortical contact, utilization of intraoperative imaging, and stem subsidence (comparison of initial postoperative radiograph to the latest follow-up radiograph-minimum 3 months) were recorded. RESULTS: There was no statistically significant difference in overall subsidence (P = .191) or the incidence of subsidence >5 millimeters between stems (P = .126). Subgroup analysis based on femoral bone loss grading showed no difference in subsidence between stems. Increased bicortical contact was associated with reduced subsidence (P = .004). Intraoperative imaging was used in 46.5% (126 of 271) of cases; this was not correlated with bicortical contact (P = .673) or subsidence (P = .521). CONCLUSION: All 3 modern TFT stems were highly successful and associated with low rates of subsidence, regardless of modular or monoblock design. Surgeons should select the stem that they feel is most clinically appropriate.

Minimum 5-Year Clinical Outcomes and Survivorship for a Single Revision Total Knee Arthroplasty System Using Hybrid Fixation and Press-Fit Stems.

BACKGROUND: Hybrid fixation, utilizing diaphyseal press-fit stems and cement fixation in the tibial and femoral metaphyseal areas, has long been a strategy for revision total knee arthroplasty (rTKA). The purpose of this study was to evaluate the clinical outcomes and survivorships of hybrid fixation using a single rTKA revision system with a minimum of 5 years follow-up. METHODS: We reviewed our prospectively collected database to identify 281 patients who underwent rTKA using a single revision system with hybrid fixation and press-fit stems between July 2006 and August 2016. We reviewed the clinical outcome scores, including the Knee Society Score, Western Ontario and McMaster Universities Osteoarthritis index, and Veterans RAND 12 Item Health Survey. We also evaluated the 5 and 10-year survivorships and the indications for reoperations. The cohort had a mean age of 70 years (range, 45.2 to 92.0) and a mean body mass index of 33.4 (range, 17.3 to 55.8). The mean time from rTKA surgery was 11.1 years (range, 5.3 to 15.5). RESULTS: Paired t-test analyses showed significant improvements from preoperative versus postoperative clinical outcome scores (P < .001) for Knee Society Score, Western Ontario and McMaster Universities Osteoarthritis, and Veterans RAND 12 Item Health Survey Physical component. Prosthetic joint infections after index rTKA were the most common failure mode with 29 patients requiring reoperations. Rerevision due to aseptic loosening was uncommon (6 patients) with a cumulative survival rate of 95.2% at 5 years and 94.2% at 10 years. CONCLUSION: The use of this single rTKA system utilizing press fit stems combined with hybrid fixation provided significant improvements in the clinical outcomes and excellent survivorships at 5 and 10 years.

Major complications after total hip arthroplasty with the direct anterior approach at a high-volume Ontario tertiary care centre.

BACKGROUND: The rate of major surgical complications for high-volume orthopedic surgeons using the direct anterior approach (DAA) in Ontario, Canada, is not known. The purpose of this study was to investigate the rate of major surgical complications after total hip arthroplasty (THA) using DAA performed by experienced orthopedic surgeons at a high-volume tertiary care centre in Ontario. METHODS: We conducted a retrospective cohort review of primary THA through DAA performed by 2 experienced fellowship-trained surgeons at an academic hospital in London, Ontario, between Jan. 1, 2012, and May 1, 2019. We excluded the first 100 cases to allow for surgeon learning curves. We recorded major surgical complications (intraoperative events, postoperative periprosthetic fractures, dislocation requiring closed or open reduction, implant failure [aseptic loosening or subsidence], early (< 6 wk) deep wound infection requiring irrigation and débridement, late (≥ 6 wk) deep wound infection requiring irrigation and débridement, and wound complications [wound dehiscence, stitch abscess, erythema, hematoma or seroma]) within 1 year of THA. RESULTS: A total of 875 primary DAA THA procedures were included. The rates of surgical complications were 0.9% for intraoperative events, 1.5% for postoperative periprosthetic fractures, 0.8% for implant failure, 0.7% for early deep wound infection, 0.1% for late deep wound infection and 3.2% for wound complications; there were no cases of dislocation. The rate of revision for implant failure within 1 year was 0.1%. Male sex was associated with a greater risk of implant failure (p = 0.01), and having a higher body mass index was associated with both increased rates of infection (p < 0.01) and having a wound complication (p < 0.01). CONCLUSION: Intraoperative events, postoperative periprosthetic fractures, implant failure, deep wound infection and wound complications accounted for the major surgical complications within 1 year of THA through DAA. The low revision rate suggests that DAA is a safe approach for THA.

Patient and Implant Performance of Satisfied and Dissatisfied Total Knee Arthroplasty Patients.

BACKGROUND: Implant migration and altered kinematics have been thought to impact patient-reported outcome measures (PROMs) and postoperative patient satisfaction. In this study comparing satisfied and dissatisfied total knee arthroplasty (TKA) patients, we hypothesized that dissatisfied patients will have greater continuous implant migration and that there will be differences in joint kinematics, objective functional measurements, and PROMs between satisfied and dissatisfied patients. METHODS: The Knee Society Score Satisfaction Subsection questions regarding satisfaction with function were used at least 6 months postoperation to split 50 patients into satisfied and dissatisfied groups. Patients underwent radiostereometric analysis to evaluate migration and kinematics. A wearable sensor system obtained objective measurements of patient function during timed up and go tests. PROMs were recorded preoperation and postoperation. RESULTS: No statistically significant differences were found in migration between satisfied and dissatisfied groups. Statistical kinematic differences existed in lateral anteroposterior contact location at 20° and 40° of flexion at 1 year, where the dissatisfied group had more anteriorly located lateral contact. No statistically significant differences were present in objective functional measurements. Satisfied and dissatisfied groups had differing PROMs at 4 timepoints or greater for each questionnaire. CONCLUSIONS: No differences were found in tibial component migration or objectively measured function between satisfied and dissatisfied patients. Functionally dissatisfied patients had more anteriorly positioned contact on the lateral condyle in early flexion and reported more pain and unmet expectations. These findings suggest that improving the functional satisfaction of TKA requires restoration of kinematics in early flexion and management of patient's pain and expectations.

Survivorship of Metaphyseal Cones and Sleeves in Revision Total Knee Arthroplasty.

BACKGROUND: Bone loss remains an anticipated challenge in revision total knee arthroplasty (rTKA). Recent efforts to enhance rTKA fixation and stability have focused on metaphyseal implants, namely cones and sleeves. We sought to compare cone and sleeve implant survivorship in rTKA. METHODS: One hundred eighty patients who underwent rTKA with metaphyseal implants from 2005 to 2018 were retrospectively reviewed. A total of 83 cones (22 femoral, 62 tibial) and 121 sleeves (58 femoral, 63 tibial) were identified. The mean age at the time of surgery was 72 years (range 43-97). Intraoperative Anderson Orthopaedic Research Institute bone loss classifications included the following: type 2A (25), type 2B (98), and type 3 (81). Mean follow-up was 41 months. RESULTS: Revision-free survival for cones was 91.3% vs 92.2% for sleeves (P = .29). Twelve knees (4 cones, 8 sleeves) underwent irrigation, debridement, and polyethylene exchange with metaphyseal implant retention for acute postoperative periprosthetic joint infection (PJI). Development of chronic PJI warranted removal of 7 cones (8.4%), 6 of which were initially placed as part of a 2-stage revision TKA. Eight sleeves (6.6%) were removed for PJI, with all initially placed during a second stage reimplantation. In the absence of infection, survival was 100% and 99.1% for cones and sleeves, respectively. One sleeve was revised for periprosthetic fracture. CONCLUSION: Metaphyseal cones and sleeves offer equally durable survivorship in revision TKA. PJI was the most common mode of implant failure in this series. Importantly, no cases of cone or sleeve aseptic loosening were observed.

Migration and Inducible Displacement of the Bicruciate-Stabilized Total Knee Arthroplasty: A Randomized Controlled Trial of Gap Balancing and Measured Resection Techniques.

BACKGROUND: The goal of this study is to investigate the migration and inducible displacement of a bicruciate-stabilized (BCS) total knee arthroplasty implanted using gap balancing (GB) or measured resection (MR) surgical techniques. We hypothesized equal migration and displacement between the techniques. METHODS: The study is a single-blinded, prospective, randomized controlled trial, with allocation of 71 patients to either GB or MR groups. Fifteen patients were withdrawn, resulting in 31 patients in the GB group and 25 in the MR group. Patients received the JOURNEY II™ BCS implant. Migration and inducible displacement were evaluated using radiostereometric analysis and patient examinations were performed at a 2-week baseline, and at 6 weeks, 3 months, 6 months, 1 year, and 2 years postoperation. RESULTS: No differences (P > .05) existed between GB and MR groups for any measurement of tibial or femoral migration. Both groups had tibial migrations below 0.5 mm from baseline to 6 months, and below 0.2 mm from both 6 months to 1 year and 1-2 years postoperation. No differences (P > .05) were found between GB and MR groups for inducible displacement. CONCLUSION: No differences were found in implant migration or inducible displacement between GB and MR groups. The BCS implant can be expected to have migration risks on par with industry standards and both surgical techniques are safe and effective options for implantation of this implant design.

A Randomized Trial Investigating the Cost-Utility of Patient-Specific Instrumentation in Total Knee Arthroplasty in an Obese Population.

BACKGROUND: Patient-specific instrumentation (PSI) has been introduced in total knee arthroplasty (TKA) with the goal of increased accuracy of component positioning by custom fitting cutting guides to the patient's bony anatomy. A criticism of this technology is the associated cost. The purpose of this randomized controlled trial was to determine the cost-utility of PSI compared with standard of care (SOC) instrumentation for TKA in an obese population. METHODS: Patients with body mass index greater than 30 with osteoarthritis and undergoing primary TKA were randomized to SOC or PSI. Patients completed a health care resource use diary and the EuroQol-5D at three, six, nine, and 12 months and the Western Ontario and McMaster Universities Osteoarthritis Index at three and 12 months postsurgery. We performed cost-utility and cost-effectiveness analyses from public health care payer and societal perspectives. RESULTS: One hundred seventy-three patients were included in the analysis with 86 patients randomized to PSI and 87 to SOC. PSI was dominated (more costly and less effective) by SOC from a health care payer perspective. From a societal perspective, an incremental cost-utility ratio was calculated at $11,230.00 per quality-adjusted life year gained, which is cost-effective at a willingness to pay threshold of $50,000. Net benefit analyses found PSI was not significantly cost-effective at any willingness to pay value from either perspective. CONCLUSION: Our results suggest that widespread adoption of PSI may not be economically attractive or clinically indicated. Future considerations are to compare long-term clinical outcomes and radiographic alignment between the groups.

Perioperative gait analysis after total hip arthroplasty: Does outpatient surgery compromise patient outcomes?

Background: There has been a continuing trend toward decreasing the length of hospital stay for patients undergoing total hip arthroplasty (THA). We aimed to investigate the impact of timing of discharge on gait and patient-reported outcomes early after THA. Methods: In this prospective observational cohort study conducted from May 2014 to November 2015, we measured gait velocity, stride length, single-limb support and single-limb support symmetry in adults aged 18-75 years before direct anterior THA, at discharge from the hospital, and 2, 6 and 12 weeks postoperatively. All procedures were performed by a single surgeon. Patients were discharged on the same day as surgery (outpatient group) or stayed at least 1 night in hospital (inpatient group). Participants also completed the Timed Up and Go test (all postoperative time points) and a series of questionnaires (Western Ontario and McMaster Universities Osteoarthritis Index [6 and 12 wk], 12-Item Short Form Health Survey [2, 6 and 12 wk], Harris Hip Score [12 wk] and a pain visual analogue scale [all postoperative time points]). Results: Thirty-six participants were enrolled in the study, of whom 16 were outpatients and 20 were inpatients. The mean pain rating at the time of discharge was lower in the outpatient group than in the inpatient group (adjusted mean difference -1.5, 95% confidence interval -3.0 to 0.0). We found no other significant differences between the groups for any gait, patient-reported or surgical outcome. Conclusion: There were no statistically significant differences in gait or patient-reported outcomes after direct anterior THA between patients who stayed overnight and those who were discharged as outpatients. Patients discharged as outpatients were younger than those who stayed overnight. Our results suggest that discharging patients as an outpatient after direct anterior THA may have a similar impact on patient function and outcomes as a standard overnight stay in hospital.

Clinical Outcomes and Midterm Survivorship of an Uncemented Primary Total Hip Arthroplasty System.

BACKGROUND: The rise in total hip arthroplasty (THA) has led to a concomitant increase in revision THAs. Tracking implant performance therefore remains a significant element of scientific inquiry to garner and maintain public trust in this procedure. There are few available reports of outcomes of a single manufacturer's total hip system outside registry data. METHODS: We performed a retrospective review of a prospectively generated database to evaluate outcomes of a single manufacturer's femoral stem and acetabular shell for THA. We report the functional outcomes, revision data, and survivorship for this total hip system. RESULTS: A total of 1942 primary THAs were implanted into 1672 patients. There were of 57 revisions. There were no cases of acetabular failure at 10-year follow-up. All functional outcome scores demonstrated significant improvements following THA. Kaplan-Meier survival analysis for all-cause revisions demonstrated 2-year implant survival of 97.6% (95% confidence interval [CI], 96.9-98.3), 5-year implant survival of 97.3% (95% CI, 96.5-98.1), and 10-year implant survival of 97.0% (95% CI, 96.0-98.0). When infection was excluded, implant survivorship improved to 99.2% (95% CI, 98.8-99.6) at 2 years, 98.9% (95% CI, 98.5-99.4) at 5 years, and 98.7% (95% CI, 98.1-99.4) at 10 years. CONCLUSION: This THA implant system comprising an uncemented press-fit acetabulum used alongside a triple-tapered femoral stem is an excellent option for THA. Implant survivorship at 2, 5, and 10 years is among the best reported for any total hip system in the world.

Indications, Survivorship, and Clinical Outcomes of a Rotating Hinge Total Knee and Distal Femoral Arthroplasty System.

BACKGROUND: Rotating hinge knee prostheses (with or without distal femoral replacement) are indicated in cases of unreconstructible bony or soft tissue compromise. Despite their versatility, these implants have demonstrated high rates of mechanical failure. We aimed to review clinical outcomes of a novel hinged knee arthroplasty system. METHODS: We reviewed all cases in a prospective database of hinged total knee arthroplasty (with and without distal femoral arthroplasty) involving a single manufacturer's implant system at a large tertiary-level academic health sciences center. We collected reasons for surgery, implant survivorship, reasons for revision, and clinical outcomes (Short Form 12, Western Ontario and McMaster Universities Osteoarthritis Index, and Knee Society Scores). RESULTS: Seventy-six cases of hinged knee implants using the knee system under investigation were performed (39 hinged total knee and 37 distal femoral replacements) between 2011 and 2018, inclusive. Indications for surgery varied, with second-stage reimplantation most common for rotating hinge and fracture most common for distal femoral arthroplasty. There were 6 revisions in the rotating hinge group (none for aseptic loosening) and 5 in the distal femoral arthroplasty group (1 for aseptic loosening). Average follow-up was 2.89 ± 2.09 years. Postoperative Short Form 12 (Physical Component), Western Ontario and McMaster Universities Osteoarthritis Index, and Knee Society Scores were 30.12 ± 10.17, 55.90 ± 21.51, and 115.62 ± 45.20, respectively. CONCLUSION: This novel hinged knee system is a highly durable option for complex and revision knee arthroplasty. Early failures tend to be secondary to infection. We observed only a single case of aseptic loosening. Although these early results are encouraging, ongoing follow-up is required to determine long-term prognosis in patients receiving this implant.

The economic impact of periprosthetic infection in total hip arthroplasty

Background: Periprosthetic joint infection (PJI) is the third leading cause of total hip arthroplasty (THA) failure. Although controversial, 2-stage revision remains the gold standard treatment for PJI in most situations. To date, there have been few studies describing the economic impact of PJI in today's health care environment. The purpose of the current study was to obtain an accurate estimate of the institutional cost associated with the management of PJI in THA and to assess the economic burden of PJI compared with primary uncomplicated THA. Methods: We conducted a review of primary THA cases and 2-stage revision THA for PJI at our institution. Patients were matched for age and body mass index. All costs associated with each procedure were recorded. Descriptive statistics were used to summarize the collected data. Mean costs, length of stay, clinic visits and readmission rates associated with the 2 cohorts were compared. Results: Fifty consecutive cases of revision THA were matched with 50 cases of uncomplicated primary THA between 2006 and 2014. Compared with the primary THA cohort, PJI was associated with a significant increase in mean length of hospital stay (26.5 v. 2.0 d, p < 0.001), mean number of clinic visits (9.2 v. 3.8, p < 0.001), number of readmissions (12 v. 1, p < 0.001) and average overall cost (Can$38 107 v. Can$6764, t = 8.3, p < 0.001). Conclusion: Treatment of PJI is a tremendous economic burden. Our data suggest a 5-fold increase in hospital expenditure in the management of PJI compared with primary uncomplicated THA.

Contexte: L'infection articulaire périprothétique (IAP) arrive au troisième rang des principales causes d'échec de l'arthroplastie (ou prothèse) totale de la hanche (PTH). Même si elle est controversée, la révision en 2 étapes demeure le traitement standard pour l'IAP dans la plupart des cas. À ce jour, peu d'études ont décrit l'impact économique de l'IAP dans l'environnement actuel des soins de santé. Le but de la présente étude était d'obtenir une estimation précise des coûts institutionnels associés à la prise en charge de l'IAP dans la PTH et d'évaluer le fardeau économique de l'IAP comparativement à une PTH primaire non compliquée. Méthodes: Nous avons passé en revue les cas de PTH primaire et de révision de PTH en 2 étapes pour cause d'IAP dans notre établissement. Les patients ont été assortis selon l'âge et l'indice de masse corporelle. Tous les coûts associés à chaque intervention ont été consignés. Des statistiques descriptives ont servi à résumer les données recueillies. Nous avons comparé les coûts moyens, la durée des séjours, les visites à la clinique et les taux de réadmission associés aux 2 cohortes. Résultats: Cinquante cas consécutifs de révision de PTH ont été assortis à 50 cas de PTH primaire non compliquée entre 2006 et 2014. Comparativement à la cohorte de PTH primaire, les cas d'IAP ont été associés à une augmentation significative de la durée moyenne du séjour hospitalier (26,5 j c. 2,0 j, p < 0,001), du nombre moyen de visites à la clinique (9,2 c. 3,8, p < 0,001), du nombre des réadmissions (12 c. 1, p < 0,001) et du coût global moyen (38 107 $ CA c. 6764 $ CA, t = 8,3, p < 0,001). Conclusion: Le traitement de l'IAP représente un énorme fardeau économique. Selon nos données, les dépenses hospitalières associées à sa prise en charge sont 5 fois plus grandes que pour la PTH primaire non compliquée.

Does Recession of the Posterior Cruciate Ligament Influence Outcome in Total Knee Arthroplasty?

BACKGROUND: For a PCL-retaining (posterior cruciate ligament) total knee arthroplasty (TKA) to function suitably, proper soft tissue balancing, including PCL recession, is required. Yet, when the recession of the PCL is needed, there is still a debate as to whether a cruciate-retaining (CR) TKA should be converted to a posterior-stabilized TKA due to the concern of instability and poorer clinical outcomes. The purpose of this study is to determine whether recession of the PCL adversely affects clinical outcomes in patients who undergo CR TKA. METHODS: CR TKAs of the same design performed by the senior author (J.M.) were identified between December 2006 and July 2015. Clinical outcome measurements were collected and included the Western Ontario and McMaster Universities Osteoarthritis Index score, the Knee Society Clinical Rating System, Short Form-12 Physical Composite Score/Mental Health Composite Score, and revision rates. RESULTS: There were no significant differences in clinical outcome when the PCL was retained, partially recessed, or completely released during PCL-retaining TKA (Western Ontario and McMaster Universities Osteoarthritis Index: P = .54, Knee Society Clinical Rating System: P = .42, Short Form-12 Mental Health Composite Score: P = .89, Short Form-12 Physical Composite Score: P = .527). CONCLUSION: This study presents evidence of similar clinical outcomes when the PCL is retained or released during PCL-retaining TKA, provided attention is paid to appropriate soft tissue balancing. CR TKA undergoing partial or complete release of the PCL should not routinely be converted to a posterior-stabilized knee design. LEVEL OF EVIDENCE: Level II, Prognostic study.