Larson, Dirk R.

We previously reported 5-year results of 57 patients with major acetabular defects (Paprosky 2B through 3B) who underwent full (31) or half (26) cup-cage reconstructions. This study provides an update with 8.8-year mean follow-up. The 10-year cumulative incidence of and survivorship free from revision, reoperation, and complications were estimated. The 10-year cumulative incidence of revision was 14% for full and 12% for half constructs. The incidence of revision for aseptic loosening was 4.3% and 4.6%, respectively. The 10-year survivorship free from aseptic loosening for patients with pelvic discontinuity was 88.9% (95% confidence interval [CI], 70.6% to 100%) and 85.7% (95% CI, 61.8% to 100%), respectively; no patient without pelvic discontinuity required revision for aseptic loosening. The 10-year cumulative incidence of complications was 42% for all patients, including a 15% incidence of dislocation. Thus, both full and half cup-cage constructs provided durable fixation for complex acetabular bone loss at 10 years, although dislocation remains a concern. Level of Evidence: Therapeutic Level IV . See Instructions for Authors for a complete description of levels of evidence.

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.

Aims Total knee arthroplasty (TKA) for end-stage osteonecrosis has historically been associated with concerns regarding aseptic loosening, and long-term data are limited. The purpose of this study was to update and expand our previous series with long-term follow-up, with specific emphasis on implant survivorship, risk factors for failure, complications, and clinical outcomes in a consecutive cohort of TKAs performed for primary and secondary osteonecrosis. Methods We retrospectively identified 295 consecutive TKAs in 266 patients for osteonecrosis performed at a single tertiary care academic institution from January 2002 to July 2022. Of these, 207 TKAs (70%) were performed for primary osteonecrosis, and 88 (30%) for secondary osteonecrosis. The predominant cause of secondary osteonecrosis was steroid use (59%; n = 52), followed by post-traumatic (25%; n = 22), radiation-induced (9%; n = 8), and alcohol-induced (7%; n = 6) osteonecrosis. Implant survivorship was analyzed as a time-to-event outcome using Kaplan-Meier estimation. The mean age was 61 years (18 to 93), with 67% being female (n = 197). The mean follow-up was nine years (2 to 20). Results The 15-year survivorship free of any revision for the entire cohort was 92% (95% CI 87 to 97), with similar rates between primary and secondary osteonecrosis (92% (95% CI 87 to 98) vs 93% (95% CI 87 to 100), respectively; p = 0.459). Varus-valgus constraint implant designs (HR 10.8 (95% CI 2.7 to 43.4); p < 0.001) and tibial stem use (HR 12.0 (95% CI 4.1 to 35.1); p < 0.001) were associated with an increased risk of any revision. The 15-year survivorship free of aseptic loosening was 97% (95% CI 93 to 100) for the entire cohort. Age under 65 years (HR 2.7 (95% CI 1.4 to 5.4); p = 0.005) and secondary osteonecrosis (HR 1.9 (95% CI 1.0 to 3.4); p = 0.044) were associated with an increased risk of any reoperation at 15 years. Conclusion TKA is a durable and reliable option for primary osteonecrosis at long-term follow-up. However, TKAs performed for secondary osteonecrosis carry a higher reoperation risk. Cite this article: Bone Joint J 2026;108-B(4):455–462.

Abstract Waldenström macroglobulinemia (WM) is characterized by recurrent MYD88 and CXCR4 mutations, whose prognostic value in patients treated with chemoimmunotherapy remains unclear. Moreover, the typically prolonged progression-free survival (PFS) correlates inconsistently with overall survival (OS), underscoring the importance of examining other surrogates. Progression of disease within 24 months (POD24), an established early end point, delineates functionally high-risk patients in other indolent lymphomas. This international study evaluated 253 patients receiving frontline fixed-duration bendamustine-rituximab (BR), a common chemoimmunotherapy for WM. At a median follow-up of 5.9 years, 5-year PFS and OS were 65% and 87%, respectively; 5-year PFS was similar between MYD88L265P (90%) and MYD88wild-type (WT) subcohorts (64% each; P = .4). Among 89 patients with known CXCR4 status, the subcohort with CXCR4mutation (28%) had shorter PFS (median 3.3 vs 8.8 years; hazard ratio [HR], 2.8; P = .0036) and OS (HR, 2.6; P = .036) compared with CXCR4WT. POD24 occurred in 11.5% of patients who demonstrated inferior subsequent OS (5-year OS, 71% vs 86%; HR, 3.1; P = .005) and higher mortality (standardized mortality ratio [SMR], 3.7), unlike the non-POD24 group, whose mortality was comparable to the matched general population (SMR, 1.1). In conclusion, BR is effective irrespective of the MYD88 status, but CXCR4 mutations and POD24 portend worse outcomes. Patients without POD24 represent a cohort with distinctly favorable outcome.

ABSTRACT Tendon adhesion is a major complication following tendon reconstruction surgery in the hand. Previous studies showed that a combination of hyaluronic acid (HA) and gelatin, covalently bound to the tendon surface, can provide a durable gliding surface to reduce adhesions in animal models both in‐vitro and in‐vivo. We have developed a similar product using good manufacturing practice (GMP) standards, in preparation for use in humans. This study aimed to examine the frictional properties and elastic modulus of the Manufactured Tendon Lubricant (MTL) when applied to an extrasynovial canine peroneus longus (PL) tendon in‐vitro. Twenty PL tendons along with the 2nd and 5th digits from adult canine forepaws, were obtained (mean age: 12 months, weight: 35 kg) from animals sacrificed in Institutional Animal Care and Use Committee (IACUC) approved protocols. Tendons were treated either with the MTL or saline solution, as a control. Eight tendons from each group (MTL vs saline‐treated) underwent friction testing, using a previously described protocol, followed by indentation testing to assess tendon elastic modulus (a marker of successful crosslinking). Two tendons from each group were not tested and were sent for scanning electron microscopy (SEM). The MTL group had significantly ( p < 0.001) lower friction and gliding resistance as well as higher elastic modulus of the PL tendons, compared to the saline group. This study demonstrates that MTL provides lubricating effects and fixation to the tendon surface and may be suitable for human testing.

Aims Arthrofibrosis affects a notable percentage of patients after total knee arthroplasty (TKA). Elevated serum mast cell tryptase (SMCT) levels have been linked to fibrosis, suggesting that SMCT could serve as a biomarker for arthrofibrosis. As such, the aims of this study were to assess SMCT levels in TKA patients, and their possible association with arthrofibrosis and clinical outcomes in a prospective clinical trial. Methods We conducted a prospective study involving 219 patients undergoing primary TKA at a single academic medical centre between January 2018 and December 2022. SMCT levels were measured preoperatively, immediately postoperatively, and at six weeks, three months, and one year postoperatively. Secondary outcomes included revision rates, complications, and Knee Society Scores (KSSs). Allergic and inflammatory conditions were assessed for their influence on SMCT levels. Results At one year postoperatively, eight patients had developed arthrofibrosis (4%), and three (1.5%) had undergone manipulation under anaesthesia. The mean preoperative SMCT level was 5.6 µg/L (SD 3.4), which decreased significantly to 4.1 µg/L (SD 2.7) immediately postoperatively (p < 0.001). At six weeks the mean SMCT level was 6.4 µg/l (SD 4.1), and was 6.1 µg/l at both three months (SD 4.1) and one year (SD 4.0). Elevated preoperative SMCT levels were not significantly associated with the risk of arthrofibrosis development (OR 3; p = 0.370), nor were immediate postoperative levels (OR 2; p = 0.754) or those at six weeks (OR 1; p = 0.989). Of note, elevated SMCT levels at three months (OR 5; 95% CI 0.4 to 64; p = 0.191) and one year (OR 13; 95% CI 1 to 232; p = 0.077) trended toward an increased risk of arthrofibrosis development, without reaching significance. Conclusion In patients undergoing TKA, with the numbers included in this study, there was no significant difference in SMCT levels between patients who did and did not develop arthrofibrosis at any timepoint. However, there was a trend towards elevated SMCT levels at three months and one year in those who developed arthrofibrosis, which merits further study. Cite this article: Bone Joint Res 2025;14(11):1045–1052.

Background: The U.S. Food and Drug Administration has approved a bupivacaine and meloxicam extended-release (ER) intra-articular injection for pain during total knee arthroplasty (TKA). However, the real-world evidence with regard to analgesic efficacy of that medication has been limited. This randomized clinical trial investigated the efficacy of this new medication compared with our standard periarticular injection for postoperative analgesia after primary TKA. Methods: Eligible patients undergoing primary, unilateral TKA for osteoarthritis at our academic center were enrolled. Patients were blinded and were randomized 1:1 to the bupivacaine-meloxicam ER (ZYNRELEF) injection group or the standard injection (ropivacaine, ketorolac, epinephrine) control group. A standardized, multimodal analgesic pathway was implemented. Numeric Rating Scale (NRS) pain scores and tallies of opioid consumption were collected. The primary outcome was the area under the curve (AUC) for NRS pain, adjusted for opioid consumption, over 72 hours. The minimal clinically important difference was considered to be 30%. Power analysis determined a minimum of 44 patients per group. The final groups included 53 patients in the experimental group and 48 patients in the control group. Results: Similar postoperative analgesia was observed, with an AUC for the adjusted NRS pain score up to 72 hours of 331 in the experimental group and 373 in the control group (p = 0.09). The mean maximum NRS pain scores were similar and reflected good, but not complete, analgesia. Scores were 3 to 5 on the day of the surgery, 4 to 6 on postoperative day (POD) 1, 5 to 6 on POD 2, and 4 to 5 on POD 3 (p > 0.05). One patient in the experimental group and 2 patients in the control group had early postoperative complications, none of which was deemed to be related to the analgesic choice. Conclusions: This randomized clinical trial demonstrated similar analgesia with a bupivacaine-meloxicam ER solution and a standard periarticular injection up to 72 hours after primary TKA. Cost, reimbursement, and convenience may ultimately prove to be more important than analgesic differences when choosing between these 2 effective options for managing postoperative pain. Level of Evidence: Therapeutic Level I . See Instructions for Authors for a complete description of levels of evidence.

We sought to develop a survival model in chronic myelomonocytic leukemia (CMML) that is primarily based on clinical variables and examine additional impact from mutations and karyotype. 457 molecularly-annotated patients were considered. Multivariable analysis identified circulating Blasts ≥2% (1 point), Leukocytes ≥13 x 109/L (1 point), and severe (2 points) or moderate (1 point) Anemia as preferred risk variables in developing a clinical risk Stratification Tool for overall survival (OS), acronymized to "BLAST": low-risk (0 points; median 63 months); intermediate-risk (1 point; median 28 months; HR 2.2, 95% CI 1.6-3.0), and high-risk (2-4 points; median 13 months; 5.4, 4.1-7.3); the corresponding 3/5 year OS rates were 68%/53%, 43%/18%, and 12%/1%. BLAST model performance (AUC 0.77/0.85 at 3/5-years) was shown to be comparable to that of the molecular CMML-specific prognostic scoring system (CMML-mol; AUC 0.73/0.75) and the international prognostic scoring system-molecular (IPSS-M; AUC 0.73/0.74). Multivariable analysis of mutations and karyotype identified PHF6MUT and TET2MUT as being "favorable" and DNMT3AMUT, U2AF1MUT, BCORMUT, SETBP1MUT, ASXL1MUT, NRASMUT, PTPN11MUT, RUNX1MUT, TP53MUT, and adverse karyotype, "unfavorable". Molecular information was subsequently encoded in a combined clinical-molecular risk model (BLAST-mol; AUC 0.80/0.86 at 3/5-years) that included the aforementioned BLAST clinical risk variables and a 3-tiered molecular risk score. BLAST and BLAST-mol were subsequently validated by two separate external cohorts. Independent risk factors for blast transformation included DNMT3AMUT, ASXL1MUT, PHF6WT, leukocytes ≥13 x 109/L, and ≥2% circulating or ≥10% bone marrow blasts. The current study proposes an easy to implement, globally applicable, and molecularly adaptive risk model for CMML.

Background Overhead athletes are susceptible to shoulder injuries, among which rotator cuff injuries are common and often directly associated with muscle weakness. Therefore, valid and reliable measures of rotator cuff strength at sport specific positions may be a vital part of sports physical therapy practice. Purpose: The current study aimed to determine the inter- and intra-tester reliability of measuring shoulder internal rotation (IR) and external rotation (ER) strength at a novel testing position, 130° of abduction and compared to the 90°/90° position. A secondary aim was to assess concurrent validity between measurements taken with the Humac® Norm™ Isokinetic Dynamometer (IKD) and Microfet® 2 hand-held dynamometer (HHD). Study Design Inter-Rater and Intra-Rater Reliability and Criterion Validity Methods Twenty-five (n=25) healthy participants were recruited for this study. Exclusion criteria included prior shoulder surgery, shoulder injury within the last three months, and contraindications to exercise according to ACSM guidelines. Participants performed maximal isometric shoulder external and internal rotation strength testing at both 90° and 130° of shoulder abduction. On the first day, participants were tested on the IKD at both positions, followed by each tester using the HHD. Participants returned 7-14 days later for repeat testing using the HHD only. ICC values were calculated for each rater, instrument, and testing position. Bland-Altman plots were created to establish limits of agreement. Minimal detectable change values were calculated. Results Inter- and intra-rater reliability for testing isometric strength using a hand-held dynamometer was good to excellent for both shoulder positions with ICC values consistently above 0.8. Concurrent validity between the HHD and IKD was poor to moderate with ICC values ranging from 0.1-0.4. However, Bland-Altman plots demonstrated that the difference in strength measures was within the limits of agreement. Conclusion Shoulder IR and ER strength testing at 130° of abduction shows strong inter-rater and intra-rater reliability for measurement in sport specific positions. Level of Evidence Level 3

Background: The direct anterior approach (DAA) is a popular approach for primary total hip arthroplasty (THA). However, the contemporary outcomes for DAA THA need further elucidation. Therefore, we aimed to describe implant survivorship, complications, and clinical outcomes after DAA THA. Methods: From our multi-institutional total joint registry, 3,184 patients who had undergone 3,698 primary DAA THA between 2010 and 2019 were identified. The identified patients had a mean age of 65 years and a mean body mass index (BMI) of 29 kg/m 2 , and 53% of patients were female. The indications for revision and reoperation and the incidence of complications were collected and analyzed. Potential risk factors, including age, sex, BMI, and high-volume compared with low-volume operating surgeons, were examined. Descriptive statistics and Kaplan-Meier survivorship with Cox regression analyses were performed. Results: At 10 years following primary DAA THA, the cohort had 96% (95% confidence interval [CI], 95% to 98%) survivorship free of any revision and 94% (95% CI, 92% to 96%) survivorship free of any reoperation. The leading indications for revision were periprosthetic joint infection (PJI) (n = 24; 5-year cumulative incidence, 0.93% [95% CI, 0.6% to 1.5%]), periprosthetic fracture (n = 20; 5-year cumulative incidence, 0.62% [95% CI, 0.4% to 1.0%]), and aseptic loosening (n = 14; 11 femoral, 3 acetabular; 5-year cumulative incidence, 0.84% [95% CI, 0.5% to 1.5%]). A BMI of ≥40 kg/m 2 was found to be significantly associated with PJI (hazard ratio [HR], 6.4; p < 0.001), reoperation (HR, 3.5; p < 0.001), and nonoperative complications (HR, 2.3; p = 0.018). Survivorship free of recurrent instability was 99.6% (95% CI, 99.4% to 99.8%) at 5 and 10 years, and the cumulative incidence of revision for instability was 0.14% at 5 years. Conclusions: In one of the largest published series to date, survivorship following DAA THA was satisfactory at early to intermediate follow-up. The leading indications for revision were PJI, periprosthetic fracture, and aseptic loosening. Instability after DAA THA was uncommon and infrequently led to revision. As a note of caution, a BMI of ≥40 kg/m 2 was identified as a risk factor for adverse outcome after DAA THA. Level of Evidence: Therapeutic Level IV . See Instructions for Authors for a complete description of levels of evidence.