Orthogate Subspecialty Journal Scan: Hip Arthroplasty & Preservation
Curated critical appraisals of recent landmark trials in hip surgery, evaluating provider variation in dual-mobility utilization, randomized dislocation survivorship in high-risk primary THA, and joint containment mechanics following periacetabular osteotomy for DDH.
- 1. Patient, Surgeon, and Institutional Variation in Dual-Mobility Use in Primary THA - The Bone & Joint Journal Level III Registry Cohort
- 2. The John Charnley Award: RCT of Dual Mobility vs Single Bearings in High-Risk Primary THA - The Journal of Arthroplasty Level I RCT
- 3. Is Femoral Head Decentration Reversible After PAO for Developmental Dysplasia of the Hip? - Clinical Orthopaedics and Related Research Level III Prospective Cohort
1. Patient, Surgeon, and Institutional Variation in Dual-Mobility Component Use in Primary Total Hip Arthroplasty: A Retrospective Cohort Study Using Data from the National Joint Registry
Authors: Zucker B, Howard J, Whitehouse M, Judge A | Journal: The Bone & Joint Journal (Sep 2026) | View Source / DOI
Situation
Dual-mobility (DM) bearing constructs are increasingly utilized in primary total hip arthroplasty (THA) to prevent postoperative dislocation. However, widespread adoption introduces elevated implant costs, unique failure mechanisms such as intra-prosthetic dislocation, and increased modular junction fretting. It remains controversial whether contemporary DM adoption reflects evidence-based patient risk stratification or unwarranted provider-level and institutional practice variation.
Background
Prosthetic instability represents one of the most common causes of early THA failure and revision. Although dual-mobility designs demonstrate favorable stability profiles in selected high-risk cohorts, unrestricted utilization in standard primary cases strains healthcare budgets without proven cost-effectiveness. In national healthcare systems, quantifying the degree to which implant selection is driven by patient-specific clinical indications versus surgeon preference and hospital purchasing habits is essential to guide clinical pathways.
Assessment & Findings
- Design & Cohort: Cross-classified multilevel logistic regression analysis of 238,455 primary THAs captured in the National Joint Registry (NJR) linked with Hospital Episode Statistics (HES) for England between January 1, 2018, and December 31, 2022. Patient risk factors were specified as fixed effects, and random effects were assigned to surgeons and hospitals to isolate provider-level clustering.
- Primary Findings: A total of 7,032 patients (2.95%) underwent DM-THA. Multilevel modeling revealed that surgeon-level factors explained 32.4% and hospital institutional factors explained 22.9% of the overall variation in DM-THA utilization. Patient-level clinical characteristics accounted for only approximately 10% of the variance (marginal R2 = 0.10), while the full model accounted for 59.8% of total variance (conditional R2 = 0.598). Findings remained consistent in sensitivity analyses restricted to high-volume arthroplasty surgeons.
- Complications / Secondary Endpoints: While patients receiving DM-THA were older, frailer, and more frequently treated for displaced femoral neck fractures, more than half of the decision (55.3% combined surgeon and hospital contribution) to select a dual-mobility construct was independent of patient pathology, demonstrating substantial unwarranted provider variation across the National Health Service.
Recommendation & Practice Takeaway
Clinical Pearl: Over 55% of the variation in dual-mobility use in primary hip arthroplasty stems from surgeon habits and hospital culture rather than objective patient dislocation risk. Arthroplasty units and surgeons must move away from idiosyncratic, preference-driven implant selection. DM bearings should be reserved for validated high-risk profiles: such as rigid spinopelvic kinematics, neuromuscular disorders, cognitive impairment, or acute displaced femoral neck fractures: to avoid unnecessary hardware expenditures and unnecessary modular wear interfaces.
2. The John Charnley Award: A Randomized Controlled Trial of Dual Mobility and Single Bearings for Patients at High Risk of Dislocation Following Primary Total Hip Arthroplasty
Authors: Potluri A, Yadav A, Weintraub M, DeBenedetti A, Della Valle C et al. | Journal: The Journal of Arthroplasty (Sep 2026) | View Source / DOI
Situation
Patients presenting for primary posterior-approach total hip arthroplasty with defined high-risk features: including prior lumbosacral spinal fusion, advanced age, or neuromuscular disorders: experience disproportionately high dislocation rates. Whether dual-mobility (DM) bearings deliver superior stability over contemporary large-diameter single-bearing (SB) femoral heads in this population has lacked Level-I randomized validation.
Background
Spinopelvic rigidity eliminates normal pelvic tilt during postural transitions from standing to sitting, precipitating prosthetic impingement and dislocation. While dual-mobility constructs increase effective femoral head jump distance and range of motion prior to impingement, they introduce secondary polyethylene interfaces and higher implant costs. Rigorous randomized evidence directly comparing DM constructs against standard modern single bearings (utilizing 36 mm or larger heads) in high-risk primary THA has been critically needed.
Assessment & Findings
- Design & Cohort: Multicenter Level-I randomized controlled trial (The John Charnley Award) allocating 555 high-risk patients undergoing primary posterior-approach THA to dual-mobility bearings (n = 271; mean effective head size 42 mm, range 36 to 55 mm) or single-bearing femoral heads (n = 284; 28 mm [n = 2], 32 mm [n = 42], 36 mm [n = 168], 40 mm [n = 61], 44 mm [n = 11]). High-risk criteria comprised prior lumbosacral fusion (n = 170) or other validated risk indicators (age >= 75 years, preoperative combined flexion-adduction-internal rotation >= 115 degrees, substance abuse, inflammatory arthritis, neuromuscular disorders, hardware removal, cognitive impairment, acute displaced femoral neck fracture, or kyphoscoliosis; n = 385). Median follow-up was 23 months (range, 3.0 to 87.2 months; 527 patients [95.0%] followed beyond 90 days).
- Primary Findings: Dislocation occurred in 2 of 271 patients (0.7%) in the DM group compared to 6 of 284 patients (2.1%) in the SB group (p = 0.29). Although this represents a threefold absolute reduction in dislocation risk favoring dual mobility, the difference did not achieve statistical significance due to lower-than-anticipated event rates in the control group. Two-year dislocation-free survivorship was 99.0% for DM versus 97.6% for SB (p = 0.63).
- Complications / Secondary Endpoints: All-cause revision occurred in 16 hips (DM: 2.2% [6/271] vs SB: 3.5% [10/284], p = 0.45), with equivalent 2-year all-cause revision-free survivorship (DM: 97.5% vs SB: 96.4%, p = 0.53). Periprosthetic joint infection was the most common revision indication (two DM [0.7%] vs five SB [1.8%]). Patient-reported outcome measures (PROMs) demonstrated no significant differences between cohorts at any postoperative timepoint (p > 0.05).
Recommendation & Practice Takeaway
Clinical Pearl: In high-risk posterior-approach THA, dual-mobility bearings achieved a 3-fold reduction in early dislocation (0.7% vs 2.1%) compared to contemporary single bearings, without increasing revision or infection rates. In patients with rigid lumbosacral fusions or neuromuscular impairment, dual-mobility remains a potent mechanical safeguard. However, when dual mobility is unavailable, combining large-diameter femoral heads (36 mm or larger) with meticulous posterior capsulolabral repair offers excellent clinical stability with a 97.6% 2-year dislocation-free survivorship.
3. Is Femoral Head Decentration Reversible After Periacetabular Osteotomy for the Treatment of Developmental Dysplasia of the Hip?
Authors: Schmaranzer F, Heimann A, Millis M, Kiapour A, Liu D et al. | Journal: Clinical Orthopaedics and Related Research (Aug 2026) | View Source / DOI
Situation
Femoral head decentration: visualized on high-resolution radial MRI as an intra-articular fluid gap between the femoral head and acetabulum: represents an objective marker of dynamic micro-instability in developmental dysplasia of the hip (DDH). Whether periacetabular osteotomy (PAO) reliably reverses this joint decentration, or whether decentration persists due to coexisting femoral version abnormalities and chondrolabral pathology, remains a critical clinical question.
Background
Bernese periacetabular osteotomy is the surgical gold standard for reorienting the deficient dysplastic acetabulum, expanding weight-bearing contact area, and retarding secondary osteoarthritis. Nevertheless, a subset of patients experiences persistent groin pain or accelerated joint breakdown despite radiographically adequate acetabular correction. Establishing whether isolated acetabular reorientation restores concentric reduction is vital for refining surgical patient selection and determining indications for concurrent femoral osteotomy.
Assessment & Findings
- Design & Cohort: Secondary analysis of a prospective cohort comprising 34 patients (34 hips; median age 27 years [IQR 20 to 30], 94% female) undergoing isolated PAO for symptomatic DDH (lateral center-edge angle < 20 degrees). All patients underwent standardized 1.5-Tesla indirect MR arthrography with delayed gadolinium-enhanced MRI of cartilage (dGEMRIC) and isotropic T2-weighted radial sequences preoperatively and at 1-year follow-up. Patients with advanced osteoarthritis (Tonnis Grade >= II), neuromuscular disorders, or gross incongruity were excluded.
- Primary Findings: Preoperatively, femoral head decentration was present in 85% of hips (29 of 34). At 1-year post-PAO, decentration completely resolved in only 31% (9 of 29 hips) and persisted in 69% (20 of 29 hips). PAO significantly reduced the median decentration distance from 4 mm to 3 mm (p < 0.001) and median radial circumferential extension from 90 degrees to 53 degrees (p = 0.003).
- Structural & Biochemical Predictors: Hips with persistent decentration exhibited significantly higher preoperative femoral anteversion (median 22 degrees vs 10 degrees, p = 0.01) and a higher preoperative acetabular index (24 degrees vs 15 degrees, p = 0.01). Furthermore, persistent decentration was strongly correlated with severe baseline intra-articular degeneration: full-thickness cartilage damage (13 of 20 [65%] vs 1 of 9 [11%], p = 0.01), subchondral cysts (14 of 20 [70%] vs 0 of 9 [0%], p < 0.001), complex labral tears (18 of 20 vs 2 of 9, p < 0.001), extensive labral tears (17 of 20 vs 3 of 9, p < 0.001), and significantly worse biochemical cartilage health via dGEMRIC (median 436 msec vs 606 msec, p = 0.004).
Recommendation & Practice Takeaway
Clinical Pearl: Acetabular reorientation alone fails to achieve concentric joint reduction in over two-thirds of dysplastic hips displaying preoperative decentration. Persistent decentration is heavily driven by excessive femoral anteversion (median 22 degrees) and advanced chondrolabral degradation. In patients presenting with pre-op radial MRI decentration and excessive femoral anteversion, surgeons should not rely solely on acetabular reorientation; thorough 3D femoral version profiling and planned concomitant femoral derotational osteotomy should be strongly considered to restore true concentric containment and protect long-term cartilage viability.
