Mark W. Pagnano

Background: Prior studies have reported higher rates of periprosthetic fracture, superficial infection, and neurologic deficit with the direct anterior approach (DAA), and higher rates of dislocation with the posterior approach (PA) for total hip arthroplasty (THA). Despite these differences, the overall clinical burden of complications between approaches remains unclear. The purpose of this study was to compare the profiles, severity, impact, and resolution of 5 clinically important complications between DAA and PA THA. Methods: A retrospective review was conducted of 11,783 consecutive primary THAs performed between 2010 and 2021 across 3 centers within a single healthcare system, using either the DAA (n = 4,451) or the PA (n = 7,332). Complications assessed included dislocation, infection, periprosthetic fracture (PPFx), aseptic loosening, and neurologic deficit. Severity was graded using the Clavien-Dindo classification (I = minor, V = death). Impact was defined by reoperation burden, and outcomes were categorized as resolved or persistent. Kaplan-Meier survivorship and propensity-weighted Cox proportional hazards models were used to compare complication risk. Results: The overall 1-year risk of surgical complications did not differ between DAA and PA (hazard ratio [HR], 0.89; 95% confidence interval [CI], 0.75-1.06; p = 0.208). Dislocation occurred more frequently with PA THA than DAA THA (1.9% vs. 0.4%; HR, 5.20; 95% CI, 3.04-8.90; p < 0.001). Superficial infections were more frequent with the DAA (1.6% vs. 0.8%; HR, 2.43; 95% CI, 1.68-3.53; p < 0.001). The risk of deep infection, PPFx, aseptic loosening, and neurologic deficit did not differ significantly between approaches. Among patients with complications, the proportion classified as severe (Clavien-Dindo III–V) was similar, and adjusted analyses showed no difference in the odds of severe complications (adjusted odds ratio 1.34 for PA vs DAA; 95% CI, 0.95-1.91; p = 0.099). Complication impact and resolution were likewise comparable. Conclusion: Although the profile of complications differed between DAA and PA THA, the severity, early clinical impact, and resolution of complications appeared similar. Notably, DAA was associated with a lower risk of dislocation and a higher risk of superficial infection compared with PA THA. Level of Evidence: Level III , Retrospective Comparative Study. See Instructions for Authors for a complete description of levels of evidence.

» The coronal plane alignment of the knee (CPAK) classification is a practical and straightforward framework to define a patient’s constitutional coronal knee limb alignment and joint line obliquity. » Patients are assigned to one of nine phenotypes using two straightforward calculations; the arithmetic hip-knee-ankle angle (aHKA) and the arithmetic joint line obliquity (aJLO). » CPAK allows clear understanding of the geographical and gender variations in knee alignment, as well as the differing outcomes of knee reconstructive surgery, based on phenotype. » CPAK enables surgeons to tailor their alignment strategy to best fit a patient’s constitutional phenotype and avoid the drawbacks of a “one-size fits all” approach.

Background: Second-generation highly cross-linked polyethylene (HXLPE) has revolutionized total hip arthroplasty. However, the long-term risks and benefits of HXLPE in primary total knee arthroplasty (TKA) remain unknown. This randomized clinical trial evaluated implant survivorship, complications, radiographic results, and clinical outcomes of HXLPE and conventional ultra-high molecular weight polyethylene (UHMWPE) inserts in primary TKAs. Methods: We enrolled 518 patients (518 knees) who underwent primary TKA in 3 centers within 1 tertiary referral network. The mean age was 67 years, the mean body mass index was 32 kg/m², and 58% of the patients were women. All of the patients underwent primary TKA with a cemented posterior-stabilized tibial insert and patellar resurfacing. Randomization proceeded via stratified dynamic allocation. The patients were blinded to their study group allocation: those in the control group (254 knees) underwent TKA with an UHMWPE insert (N2Vac; Stryker); those in the treatment group (264 knees) received an HXLPE insert (X3; Stryker). Kaplan-Meier survivorship, radiographic results, and clinical outcomes were assessed. This trial was registered with ClinicalTrials.gov. The mean follow-up was 11 years. Results: The 10-year overall survivorship free from any revision and from any reoperation was 96% and 94%, respectively. There were no differences in the risk of revision or reoperation between the groups (p > 0.05). There were a total of 19 revisions. Revision indications included periprosthetic joint infection (14 knees), instability (4 knees), and open reduction and internal fixation (ORIF) for a patellar fracture due to osteolysis around a UHMWPE insert (1 knee). There were no revisions due to polyethylene wear, osteolysis, or fracture of the post in the HXLPE group. The radiographic results and clinical outcomes were otherwise similar. Conclusions: Notably, no wear-related failures were identified in the HXLPE group, but there was 1 case of osteolysis in the UHMWPE group. Level of Evidence: Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.

Background: The rates of obesity among patients undergoing total knee arthroplasty (TKA) have substantially increased. In addition, obesity is a well-established risk factor for complications after TKA. The purpose of this study was to analyze trends in body mass index (BMI) and complication risk among obese patients undergoing primary TKA treated at a single institution over 3 decades. Methods: Utilizing an institutional total joint registry, 13,919 primary TKAs performed to treat osteoarthritis between 1990 and 2019 were identified. Patients were stratified by BMI according to the World Health Organization (WHO) classification into 3 groups: non-obese (BMI, 2), WHO Class-I and II obese (BMI, 30 to 39.9 kg/m²), and WHO Class-III obese (BMI, ≥40 kg/m²). Trends in BMI and survivorship free from reoperation, revision, and periprosthetic joint infection (PJI) were analyzed over time while controlling for age, sex, and the Charlson Comorbidity Index. Results: Over the study period, there was a 90% increase in the prevalence of Class-II obesity (13% to 25%) and a 300% increase in Class-III obesity (3% to 12%). Analysis of the entire cohort demonstrated a decrease in the 2-year risk of any reoperation, any revision, and PJI (p < 0.05 for all) with time. The risk decreased significantly over time for non-obese patients for any reoperation (p = 0.029) and any revision (p = 0.004) and for Class-III obese patients for any reoperation (p = 0.038) and any revision (p = 0.012), but it remained stable for Class-I and II obese patients. The risk of PJI decreased from 1990 to 2019 for non-obese patients (p = 0.005), but there were no significant changes in PJI risk for any obesity group. Conclusions: Despite increasing rates of obesity among our patients who underwent TKA, we observed decreasing risks of reoperation, revision, and PJI over time. The risks of reoperation and revision declined among non-obese patients, remained stable for Class-I and II obese patients, and declined for Class-III obese patients. The PJI risk declined for non-obese patients over the study period, but no such decline occurred for any category of obesity. Despite the decreasing risks of reoperation and revision, further work is needed to improve PJI risk in obese patients. Level of Evidence: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Background: Porous metaphyseal cones are frequently utilized during revision total knee arthroplasty (TKA) procedures. The purpose of the present study was to evaluate 3D-printed metaphyseal cones used for revision TKA, with specific emphasis on implant survivorship, radiographic appearance, and clinical outcomes after short-term follow-up. Methods: We identified 740 cones (498 tibial, 242 femoral) that had been inserted during 533 revision TKA procedures that had been performed at a single tertiary care academic institution. Aseptic loosening (n = 199), periprosthetic joint infection (PJI) (n = 183), and instability (n = 84) were the most common reasons for the index revision. Type-2B or 3 bone loss was present in 67% of the knees. The mean age was 66 years, the mean body mass index was 34 kg/m², and 55% of the patients were female. Serial radiographs were reviewed. The mean duration of follow-up was 4 years. Results: The 5-year cumulative incidence of cone revision for aseptic loosening was 1% (95% confidence interval [CI], 0% to 3%). The 5-year cumulative incidence of any cone revision or removal was 6% (95% CI, 4% to 9%). In total, 37 cones (19 femoral, 18 tibial) were revised, with PJI (n = 23; 14 recurrent), periprosthetic femoral fracture (n = 3), arthrofibrosis (n = 3), and aseptic loosening of the femoral component and femoral cone (n = 3) as the most common reasons for cone revision. The 5-year cumulative incidence of any TKA re-revision was 14% (95% CI, 11% to 18%). There were a total of 67 re-revisions, with PJI (n = 38), persistent drainage (n = 6), and extensor mechanism disruption (n = 3) being the most common reasons. Radiographically, 2 unrevised femoral cones and 1 unrevised tibial cone appeared to be possibly loose; all 3 cones were in knees with distal femoral replacements or hinged constructs. Conclusions: This large series showed that 3D-printed titanium metaphyseal cones were very durable at short-term follow-up, with a 5-year cumulative incidence of cone revision for aseptic loosening of 1%. PJI was the most common reason for cone revision and any revision. Level of Evidence: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

FEWER SUBSEQUENT REVISIONS WITH MODULAR DUAL-MOBILITY CONSTRUCTS THAN LARGE FEMORAL HEADS IN REVISION TOTAL HIP ARTHROPLASTIES AT TEN YEARS

Background: The specific advantages of spinal anesthesia compared with general anesthesia for primary total hip arthroplasty (THA) remains unknown. Therefore, this study aimed to investigate the pain control, length of stay, and postoperative outcomes associated with spinal anesthesia compared with general anesthesia in a large cohort of primary THAs from a single, high-volume academic institution. Methods: We retrospectively identified 13,730 primary THAs (11,319 patients) from 2001 to 2016 using our total joint registry. Of these cases, 58% had general anesthesia and 42% had spinal anesthesia. The demographic characteristics were similar between groups, with mean age of 64 years, 51% female, and mean body mass index (BMI) of 31 kg/m². Data were analyzed using an inverse probability of treatment weighted model based on a propensity score that accounted for numerous patient and operative factors. The mean follow-up was 6 years. Results: Patients treated with spinal anesthesia had lower Numeric Pain Rating Scale (NPRS) scores (p < 0.001) and required fewer postoperative oral morphine equivalents (OMEs) at all time points evaluated (p < 0.001). Patients treated with spinal anesthesia also had shorter hospital length of stay (p = 0.02), fewer altered mental status events (odds ratio [OR], 0.7; p = 0.02), and fewer intensive care unit (ICU) admissions (OR, 0.7; p = 0.01). There was no difference in the incidence of deep vein thrombosis (p = 0.8), pulmonary embolism (p = 0.4), 30-day readmissions (p = 0.17), 90-day readmissions (p = 0.18), all-cause revisions (p = 0.17), or all-cause reoperations (p = 0.14). Conclusions: In this large, single-institution study, we found that spinal anesthesia was associated with reduced pain scores and OME use postoperatively. Furthermore, spinal anesthesia resulted in fewer altered mental status events and ICU admissions. These data favor the use of spinal anesthesia in primary THAs. Level of Evidence: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.