Survivorship of Modern Cementless Total Knee Arthroplasty: Analysis From the Canadian Joint Replacement Registry.

BACKGROUND: Cementless total knee arthroplasty (TKA) is rising in popularity. The literature supporting its use over cemented TKA remains sparse. Using the Canadian Joint Replacement Registry (CJRR), we sought to investigate cementless versus cemented fixation in modern primary TKA and (1) determine whether there is an overall difference in revision by fixation, (2) perform a subanalysis of the most-commonly used cementless TKA brand in Canada, and (3) identify the reasons for revision. METHODS: The CJRR data was used to analyze TKA designs with cemented and cementless versions. Revision risk is reported as all-cause cumulative percent revision (CPR). Reasons for revision were analyzed. Cox proportional hazards models were used to report adjusted hazard ratios (HR) controlling for age, sex, patella resurfacing, and bearing constraints. We included 202,880 primary TKAs performed between 2012 and 2021. Of those, 9,163 (4.5%) were cementless. RESULTS: The CPR at 8 years was 4.49% for cementless and 3.14% for cemented implants. After adjusting for confounders, we did not detect a difference in revision risk overall (HR 0.87 [95% CI (confidence interval) 0.73 to 1.04], P = 0.128). However, the most commonly used cementless TKA brand demonstrated a CPR of 1.95% compared to 2.19% for its cemented version at 4 years. Furthermore, we detected a significantly lower revision risk compared to its cemented version after adjusting for confounders (HR 0.66 [95% CI 0.51 to 0.85], P = 0.001). The 4 most common reasons for revision in both groups were the following: (1) infection, (2) instability, (3) aseptic loosening, and (4) pain of unknown origin. CONCLUSIONS: Using CJRR data adjusted for confounding factors, no difference in revision risk was detected between cemented and cementless implants overall. However, for the most common brand of cementless TKA used in Canada, there was a lower risk of revision than its corresponding cemented version. The reasons for revision were similar.

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.

Minimum 15-Year Survival of a Biconvex Inlay Patellar Component in Primary Total Knee Arthroplasty: An Analysis of 2,530 Total Knee Arthroplasties From a Single Institution.

BACKGROUND: Routine patellar resurfacing during primary total knee arthroplasty (TKA) remains controversial. To our knowledge, there are no studies reporting the long-term performance of a cemented biconvex all-polyethylene inlay component implanted at the time of primary TKA. The purpose of this study was to examine the 15-year survivorship and long-term clinical outcomes of this biconvex inlay patella used at our institution. METHODS: We retrospectively reviewed our prospectively collected institutional database and identified 2,530 patients who underwent cemented TKA with a single prosthetic design (from 1996 to 2007) where the patella was resurfaced using this cemented biconvex inlay patella. The mean age at surgery was 68 years (range, 29 to 93). The mean body mass index was 33.0 (range, 16.4 to 76.3), with 61.9% women. At the time of analysis, the mean time from surgery was 20.4 years (range, 15 to 26). We used Kaplan-Meier analysis to calculate survivorship at 15 years. We analyzed clinical outcomes using 3 patient-reported outcome measures collected prospectively. RESULTS: The 15-year survivorship with revision surgery for all causes as the end point was 97.1% (95% confidence interval 96.1 to 98.1%). The 15-year survivorship with revision surgery for a patella-related complication as the end point was 99.7% (95% confidence interval 99.4 to 1.0). At the final follow-up, patients showed significant improvement in scores for the Knee Society Clinical Rating System (P < .001), Western Ontario and McMaster University Osteoarthritis Index (P < .001), and Veterans Rand 12-Item Health Survey physical component (P < .001). CONCLUSIONS: Routine patellar resurfacing using a biconvex inlay patellar component has excellent survivorship and a low rate of complications at 15 years post-TKA.

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.

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.

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.

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 2-Year Outcomes of a Novel 3D-printed Fully Porous Titanium Acetabular Shell in Revision Total Hip Arthroplasty.

Background: Fully porous acetabular shells are an appealing choice for patients with extensive acetabular defects undergoing revision total hip arthroplasty (rTHA). This study reports on the early outcomes of a novel 3-D printed fully porous titanium acetabular shell in revision acetabular reconstruction. Methods: A multicenter retrospective study of patients who received a fully porous titanium acetabular shell for rTHA with a minimum of 2 years of follow-up was conducted. The primary outcome was rate of acetabular revision. Results: The final study cohort comprised 68 patients with a mean age of 67.6 years (standard deviation 10.4) and body mass index of 29.5 kg/m2 (standard deviation 5.9). Ninety-four percent had a preoperative Paprosky defect grade of 2A or higher. The average follow-up duration was 3.0 years (range 2.0-5.1). Revision-free survivorship at 2 years was 81% for all causes, 88% for acetabular revisions, and 90% for acetabular revision for aseptic acetabular shell failure. Eight shells were explanted within 2 years (12%): 3 for failure of osseointegration/aseptic loosening (4%) after 15, 17, and 20 months; 3 for infection (4%) after 1, 3, and 6 months; and 2 for instability (3%). At the latest postoperative follow-up, all unrevised shells showed radiographic signs of osseointegration, and none had migrated. Conclusions: This novel 3-D printed fully porous titanium shell in rTHA demonstrated good survivorship and osseointegration when used in complex acetabular reconstruction at a minimum of 2 years. Level of evidence: IV, case series.

Cement Mantle Quality and Stem Alignment in Cemented Collarless Polished Tapered Stems Implanted via the Direct Anterior and Direct Lateral Approaches: A Single Institution Experience.

BACKGROUND: The aim of this study was to compare the stem alignment and the quality of cement mantle of collarless polished tapered cemented stems inserted through the direct anterior approach (DAA) and the direct lateral approach (DLA). METHODS: A comparative retrospective study of 232 hybrid total hip arthroplasties using a cemented collarless polished tapered stem through either the DAA (n = 147) or DLA (n = 85) was performed. Radiographic evaluation included stem alignment, cement mantle quality, and cement mantle thickness. RESULTS: On anteroposterior radiographs, stems implanted through the DLA were more likely to be in neutral alignment, than those implanted through the DAA (83.5%[n = 71] versus 71.4% [n = 105]; P = <.001). No difference between approaches was noted for stem alignment on lateral radiographs or cement mantle quality. Multivariate analysis revealed factors associated with suboptimal cement mantle and included Dorr type B or C femur as well as male gender. A mean cement mantle thickness ≥2mm was achieved in all Gruen zones for both approaches. CONCLUSION: In our series, the DAA was associated with a higher incidence of coronal plane stem malalignment compared to the DLA when using cemented tapered polished femoral components for total hip arthroplasty. No difference in lateral stem alignment or cement mantle quality was found.