Abstract Revision knee data from six joint arthroplasty centers were compiled for 2010 and 2011 to determine mechanism of failure and time to failure. Aseptic loosening was the predominant mechanism ...of failure (31.2%), followed by instability (18.7%), infection (16.2%), polyethylene wear (10.0%), arthrofibrosis (6.9%), and malalignment (6.6%). Mean time to failure was 5.9 years (range 10 days to 31 years). 35.3% of all revisions occurred less than 2 years after the index arthroplasty, 60.2% in the first 5 years. In contrast to previous reports, polyethylene wear is not a leading failure mechanism and rarely presents before 15 years. Implant performance is not a predominant factor of knee failure. Early failure mechanisms are primarily surgeon-dependent.
Abstract Background Despite increasing interest in the anterior approach for cementless, primary total hip arthroplasty (THA), studies examining the incidence of periprosthetic fractures with this ...approach are lacking. The purpose of this study was (1) to investigate the incidence of early periprosthetic fractures associated with primary THA performed through an anterior supine intermuscular (ASI) approach without the use of a specialized table and (2) to identify potential risk factors for these fractures. Methods We identified 2869 primary THA performed via the ASI approach using a single cementless, tapered titanium femoral component with short and standard length options between February 2007 and April 2014. Fifty-two percent of THA were in female patients while 48% were in males. Short stems were used in 59% versus standard length in 41%. Results There were 26 (0.9%) early periprosthetic femoral fractures, with 23 requiring revision. When looking at the potential risk factors of age, gender, BMI and stem length, the only significant finding was that increased age was associated with increased risk of femoral fracture. Logistic regression analysis revealed a significant age/fracture association for female gender only, which remained when controlled for BMI, stem length, or both. Conclusion The muscle-sparing ASI approach appears to be a safe technique for performing primary THA when used in a suitable patient population. The early periprosthetic femoral fracture rate in our series may warrant consideration of utilizing a different design or different approach in elderly female patients.
Abstract A total of 2235 primary total knee arthroplasties (TKAs) and 605 unicompartmental knee arthroplasties performed at 3 institutions over 5 years were reviewed to compare the incidence of ...postoperative complications between these groups. The overall risk of complications for patients undergoing TKA was 11.0%, compared with 4.3% for patients undergoing unicompartmental knee arthroplasty ( P < .0001). Total knee arthroplasty was associated with increased rates of manipulation (odds ratio OR, 13.0; P < .0001), transfusion (OR, 8.5; P = .036), intensive care unit admission (OR, 7.4; P = .049), discharge to a rehabilitation facility (OR, 5.2; P < .0001) and had longer hospital stays (mean, 3.3 vs 2.0 days; P < .0001). There was a trend toward an increased risk of deep infection (0.8% vs 0.2%, P = .13), readmission (4.2% vs 2.7%, P = .0795), thromboembolic events (1.0% vs 0.64%, P = .398), and any reoperation (1.4% vs 0.6%; P = .064). The increased risk of perioperative complications after TKA should be considered when counseling patients if they are an appropriate candidate for either procedure.
Abstract The femoral component and proprietary instrumentation of a mobile-bearing unicompartmental knee arthroplasty (UKA) was redesigned with an additional peg for enhanced fixation, 15° of extra ...femoral surface for contact in deep flexion, more rounded profile, better fit into the milled surface, and redesigned intramedullary based instrumentation. To assess the benefit of these changes, we compared postoperative radiographs of 219 single-peg and 186 twin-peg UKAs done in 2008–2011. All surviving knees demonstrated satisfactory position and alignment with no radiolucencies observed. Radiographic analysis showed improved and consistent component positioning with the twin-peg design implanted with updated instrumentation compared with the single-peg. The radiographic benefits of improved implant positioning using the twin-peg component and updated instrumentation are clear and carry tremendous potential. More robust follow-up is imperative.
Abstract Although ‘dual taper’ modular stems with interchangeable modular necks have the potential to optimize hip biomechanical parameters, there is increasing concern regarding the occurrence of ...adverse local tissue reactions from mechanically assisted crevice corrosion at the neck–stem taper junction. A systematic treatment approach (risk stratification algorithm) based on the currently available data is recommended to optimize patient management. While specialized tests such as metal ion analysis and MARS MRI are useful modalities in evaluating for adverse tissue reactions, over-reliance on any single investigative tool in the clinical decision-making process should be avoided. There should be a low threshold to perform a systematic evaluation of patients with dual taper stem total hip arthroplasty as early recognition and diagnosis will facilitate the initiation of appropriate treatment.
Abstract Background The purpose of this study was to compare patient-reported outcomes and revision rates between medial unicompartmental knee arthroplasty (UKA) patients based on the presence of ...medial bone marrow lesions (BMLs) and/or partial- versus full-thickness cartilage loss. Methods BML were graded on preoperative MRIs from 174 UKA performed between 2009 and 2013 using the MRI Osteoarthritis Knee Score (MOAKS) criteria by a single evaluator blinded to the patient’s outcome. A second evaluator blinded to the MRI findings and postoperative outcomes assessed medial joint space present on both weight-bearing and valgus stress radiographs. Pre- and postoperative Knee Society Knee Scores (KSS), Pain Scores (PS), and Function Scores (FS) were then compared between four groups of patients: patients with BML with either partial- or full-thickness cartilage loss, and patients without BML with either partial- or full-thickness cartilage loss. Results 152/174 (87%) had minimum two-year follow-up. One patient in the No BML/Full-thickness loss group was converted to TKA secondary to arthrofibrosis; however, there were no statistical differences in revision rate between the four groups as no other revisions were performed (p=0.61). Similarly, pre- and postoperative KSS, PS, and FS did not differ between groups, nor did postoperative UCLA activity scores. Conclusion Medial tibial BMLs were not associated with inferior outcomes, either in patients with partial- or full-thickness cartilage loss. While the current results do not allow for the presence of preoperative BML to be considered an indication for UKA, these results definitively support that BMLs are not a contraindication for medial UKA.
Abstract A total of 223 consecutive total hip or total knee arthroplasties were evaluated for periprosthetic joint infection (PJI) using leukocyte esterase reagent (LER) strips. Fifty-two LER strips ...were read as positive (23.3%), 106 were read as negative (47.5%), and 65 strips (29.2%) were unable to be read secondary to debris or blood in the aspiration. Using a synovial fluid white blood cell count of greater than 3000 white blood cell per microliter as an indicator of PJI, the sensitivity and specificity were 92.9% and 88.8%, respectively. When using positive cultures for diagnosis of PJI, sensitivity and specificity were 93.3% and 77.0% and 100% and 86.8% for the cases where a reoperation was performed and a combination of factors were used to define PJI. Leukocyte esterase reagent strips represent a rapid, inexpensive, and sensitive tool for the diagnosis of PJI. Their utility is limited, however, by blood or debris in the synovial fluid rendering them unreadable in one-third of cases.
Abstract Background Total knee arthroplasty is overall a very successful surgery, but complications do occur. These complications include aseptic loosening of the tibial component, and obese patients ...are among the highest risk group. High-viscosity cement (HVC) has been implicated as a possible cause for aseptic loosening of the tibial component. The purpose of this study was to evaluate the incidence of aseptic loosening of the tibial component in obese patients with the use of HVC and standard tibial tray. Methods We identified 1366 obese patients (1851 knees) with a body mass index >35 kg/m2 and 2-year minimum follow-up who underwent primary total knee arthroplasty using HVC and a symmetrical, grit-blasted, cobalt-chrome tibial component with 40-mm stem. Preoperative and postoperative range of motion, Knee Society (KS) scores, complications, and reoperations were evaluated. Specifically, we assessed the rate of tibial aseptic loosening. Results At a mean 5.4 years follow-up, only 1 in 1851 knees had aseptic loosening of the tibial component for an incidence of 0.054%. There was a mean increase of 3.3 degrees of knee range of motion. KS pain level decreased by 38.6 points (50 point scale). KS clinical scores improved by 52.2, Knee Society functional scores improved by 19.5, University of California, Los Angeles, activity score improved by 0.9, and Oxford Knee Score by 15.7. All these improvements were statistically significant with P < .001. Conclusion Standard tibial components and HVC can be used in most patients, including the high-risk obese group, with low rates of tibial aseptic loosening.
Abstract Background Revision TKA poses unique challenges compared with primary TKA such as bone loss, deformity and ligament instability. Modular component options allow flexibility to deal with ...these complexities. The purpose of this study was to evaluate midterm outcomes for revision TKA using a modular revision knee system with complete interchangeability and multiple options for augmentation, offset, constraint, and stem extensions. Materials and Methods A query of our practice registry revealed 257 consented patients (274 knees, 278 TKA) with minimum 2-year follow-up who underwent aseptic revision TKA with a modular system (Vanguard SSK, Zimmer Biomet, Warsaw, Indiana) between 2005 and 2013. Four patients were re-revised to a second Vanguard SSK within the study period. Mean age was 68 years, and mean number of previous surgeries was 2 (1-14). Results At mean follow-up of 6.0 years (range, 2-11 years) there have been 25 aseptic revisions involving one or more components (9.0%): 15 aseptic loosening with concomitant instability in two, 8 others with instability, one hypersensitivity, and one revised elsewhere for unknown cause. Ten knees were revised for infection. ROM improved from 100° preoperatively to 105° most recently. Knee Society clinical scores improved from 45 to 79, and function scores from 46 to 56. Radiographic evaluation revealed satisfactory position, fixation and alignment in 97% and abnormal findings in 7 knees: 4 limited to the patella, one tibial radiolucency, one femoral and tibial radiolucency, and one tibial subsidence. Conclusion The results of this modular TKA revision system at 6 years mean follow-up are promising for use in complex scenarios, with a low frequency of aseptic re-revision, good knee stability, and substantial improvements in ROM and clinical and functional outcomes.
The anterior-supine intermuscular approach is a truly muscle-sparing approach to total hip arthroplasty with a low complication rate. The advantages include improved early recovery and return to ...everyday activities. The authors found the learning curve to be around 40 cases and 6 months in a high-volume joint surgeon's practice. This article provides a detailed description of the surgical approach, including the use of a standard operating room table and fluoroscopy. Cadaver dissections and one-on-one mentoring are recommended when implementing this approach in one's practice.
