Evidence-Based Data for Stem Selection

1. High-Yield Summary

• Core Clinical Objective: Evidence-based selection of femoral stem components in primary total hip arthroplasty (THA) tailored to patient age, biological bone quality (Dorr classification), proximal canal geometry, and individual periprosthetic fracture risk profiles.
• Fixation Philosophy Paradigm: Cementless tapered-wedge stems dominate contemporary adult reconstruction practice; however, global registry data demonstrate clear clinical advantages for cemented femoral stems or collared cementless stems in patients aged 70 years and older, particularly females with osteoporotic bone.
• Morphological Classification: Modern cementless femoral stems are categorized according to the Khanuja classification (Types 1 through 6), differentiating single-wedge, double-wedge, tapered round/fluted, cylindrical fully coated, modular, and anatomic geometries by their distinct proximal versus diaphyseal load transfer zones.
• The Collared Stem Benefit: High-volume national registry studies confirm that incorporating a medial collar on cementless tapered-wedge stems reduces early postoperative periprosthetic femoral fracture rates by more than 60% in elderly female cohorts, achieving fracture risk profiles comparable to cemented fixation.
• Bone Quality Matching (Dorr Criteria): Dorr Type A bone favors cementless tapered-wedge fixation; Dorr Type B allows versatile fixation with careful canal preparation; Dorr Type C (stovepipe, thin cortices, osteopenic canal) strongly indicates cemented polished taper-slip stems or collared compaction-fit designs.

2. Anatomy and Biomechanics

Proximal Femoral Geometry and Anatomy

Successful femoral reconstruction requires anatomic restoration of the hip center of rotation, horizontal femoral offset, abductor lever arm length, and vertical limb length. The proximal femur presents complex three-dimensional geometric parameters:

• Neck-Shaft Angle: Averages 125 to 135 degrees. Coxa vara (< 120 degrees) increases bending moments and abductor mechanical advantage but increases shear stresses across the femoral neck and implant interface. Coxa valga (> 135 degrees) decreases abductor lever arm, necessitating lateralized or high-offset stem configurations.
• Femoral Anteversion: Typically ranges between 10 and 15 degrees anterior to the posterior condylar axis of the distal femur. Uncemented straight stems track native anteversion unless modularity or conical splined geometries allow independent version adjustment.
• Horizontal Femoral Offset: The perpendicular distance between the center of rotation of the femoral head and the long anatomical axis of the femoral shaft. Restoration of native offset restores soft-tissue abductor tension, minimizes polyethylene edge-loading, and eliminates impingement without artificially lengthening the limb.
• Calcar Femorale: A dense vertical plate of cortical bone originating at the posteromedial junction of the femoral shaft deep to the lesser trochanter, radiating toward the greater trochanter. The calcar represents the primary anatomical pillar resisting compressive and axial loads in the proximal medial femur.

Biomechanical Load Transfer Principles

Load transmission down the proximal femur follows Wolff’s law: bone remodels in response to mechanical stress. The location and extent of implant fixation dictate subsequent periprosthetic remodeling:

• Metaphyseal (Proximal) Load Transfer: Tapered-wedge and fit-and-fill designs engage the proximal metaphyseal trabeculae, transferring physiologic compressive and hoop stresses across Gruen zones 1 and 7 (calcar and greater trochanter). This preserves proximal cortical density and limits distal stress bypass.
• Diaphyseal Load Transfer and Stress Shielding: Cylindrical, extensively porous-coated stems achieve rigid axial and torsional stability in the femoral isthmus (Gruen zones 3, 4, and 5). Because the stiff metallic implant bears the mechanical load across the diaphysis, the bypassed proximal metaphysis undergoes adaptive bone resorption (stress shielding), particularly in Gruen zone 7.
• Hoop Stresses vs. Shear Stresses: Wedge-shaped cementless implants convert axial joint reaction forces into lateral expansion hoop stresses within the cortical ring. In thick, elastic bone (Dorr A), hoop stresses establish secure frictional interference fit. In thin, brittle, or osteopenic cortices (Dorr C), hoop stresses exceed the tensile yield strength of cortical bone, predisposing to intraoperative splitting or early postoperative periprosthetic fractures.

3. Pathogenesis and Mechanisms of Stem Failure

Implant failure and revision surgery in primary total hip arthroplasty stem from distinct biological, mechanical, and patient-specific failure pathways:

Aseptic Loosening and Micromotion

Stable biological fixation of cementless implants requires bone ingrowth into porous surface structures (mean pore size 100 to 400 micrometers). If initial primary mechanical stability is inadequate, interface micromotion exceeding 150 micrometers inhibits osteoblast differentiation and promotes the formation of an unstable fibrous interface membrane. Subsequent cyclic loading releases polyethylene or metallic wear particles into the effective joint space, activating macrophage-mediated osteoclastogenesis (RANK/RANKL pathway) and progressive periprosthetic osteolysis.

Periprosthetic Femoral Fractures

Periprosthetic fractures represent the most rapidly escalating complication in modern hip arthroplasty. Intraoperative fractures typically occur during canal preparation (broaching) or final implant seating, presenting as calcar fractures or vertical longitudinal splits. Postoperative fractures follow low-energy falls within the first 90 days after surgery. Modern registry analyses demonstrate that collarless, single-wedge cementless stems placed in elderly osteoporotic bone act as mechanical wedges during minor axial trauma, causing splitting of the proximal femoral cylinder.

Stem Subsidence and Thigh Pain

Early stem subsidence exceeding 2 to 3 millimeters within the first 6 to 12 weeks signifies undersizing or failure of initial cortical engagement. Subsidence alters limb length, slackens abductor tension, and leads to posterior cup impingement and anterior dislocation. Thigh pain reflects structural modulus mismatch, micro-motion at the stem tip, or excessive load transfer at the diaphyseal contact point.

4. Natural History and Registry Survivorship

Data from international total joint registries—including the National Joint Registry of England, Wales, Northern Ireland and the Isle of Man (NJR), the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR), the Swedish Hip Arthroplasty Register (SHAR), and the Swiss National Joint Registry (SIRIS)—provide conclusive long-term population-based survivorship curves:

• Young and Active Cohorts (< 65 Years): Cementless stems demonstrate superior or equivalent 15- to 20-year revision-free survivorship (> 96%), with robust biological fixation avoiding the late cement mantle fatigue failure documented in historic young cohorts.
• Elderly Cohorts (≥ 70 to 75 Years): Modern registries consistently document a significantly higher cumulative revision rate for collarless cementless stems compared to cemented stems. The primary driver of revision in elderly cementless cohorts is periprosthetic femoral fracture occurring within the first 12 to 24 months postoperatively.
• Sex-Specific Fracture Vulnerability: Female patients older than 70 years receiving collarless cementless stems have an adjusted hazard ratio for periprosthetic fracture revision between 2.0 and 2.5 compared to females receiving cemented stems. In contrast, male patients with dense cortical bone experience low fracture risks across both fixation philosophies.

5. Clinical Presentation and Patient Evaluation

Preoperative Clinical Stratification

Preoperative patient evaluation must identify systemic and local bone quality risk factors that dictate implant choice:

• Chronological and Biological Age: Assess physiological reserve, functional mobility, and life expectancy. Chronological age over 75 years, low body mass index (< 20 kg/m²), or severe frailty favors cemented or collared fixation.
• Bone Mineral Density (DEXA): History of fragility fractures (distal radius, vertebral compression, contralateral hip) or a femoral neck T-score < -2.5 indicates high fracture susceptibility, mandating cemented stems or collared compaction-fit stems.
• Secondary Osteoporosis Risk Factors: Chronic corticosteroid use, inflammatory arthropathies (rheumatoid arthritis, ankylosing spondylitis), chronic renal failure, and smoking compromise cortical architecture and cellular osteogenic healing capacity.

Physical Examination Benchmarks

Essential physical diagnostic evaluations include:

• Gait Analysis & Trendelenburg Test: Evaluates abductor muscle competence. Chronic abductor avulsion or severe insufficiency requires meticulous offset restoration to avoid persistent postoperative limp.
• Limb Length Measurement: Differentiate true structural leg length discrepancy (anterior superior iliac spine to medial malleolus) from apparent discrepancy due to fixed pelvic obliquity or adduction contractures.
• Neurovascular Examination: Document baseline sciatic and femoral nerve function, and palpate distal pulses.

6. Imaging, Radiographic Measurements, and Digital Templating

Standard Radiographic Series

Mandatory preoperative radiographs include a standing low anteroposterior (AP) pelvis centered on the superior border of the pubic symphysis with bilateral lower extremities positioned in 15 degrees of internal rotation, and a true lateral (cross-table or shoot-through) radiograph of the operative hip.

Radiographic Measurements

• Canal Flare Index (CFI): Calculated as the ratio of femoral canal width 20 mm proximal to the lesser trochanter to canal width at the narrowest isthmus. CFI > 4.7 defines a “champagne flute” canal (Dorr A); 3.0 to 4.7 defines a normal funnel shape (Dorr B); < 3.0 defines a cylindrical “stovepipe” canal (Dorr C).
• Cortical Thickness Index (CTI): Ratio of cortical width to total femoral diameter at 100 mm below the lesser trochanter. CTI < 0.50 signifies severe cortical thinning and heightened fracture risk.
• Horizontal and Vertical Offset: Measured from the femoral shaft axis to the center of the femoral head, and from the lesser trochanter reference line to the head center.

Digital Templating Workflow

Preoperative digital templating predicts component sizing within one size in over 90% of cases and guides critical operative benchmarks:

• Identify the planned femoral neck osteotomy height measured in millimeters above the lesser trochanter.
• Determine the optimal stem size that fills the proximal metaphysis without diaphysial contact impingement.
• Verify offset restoration: select high-offset or standard-offset geometries to recreate native abductor tension while keeping leg lengths equal.

7. Classification Systems

The selection of femoral stems relies on validated morphological and implant design classification systems formatted below.

Dorr Proximal Femoral Bone Morphology Classification

Dorr Type	Cortical Thickness & Canal Geometry	Canal Flare Index (CFI)	Histomorphometric Bone Quality	Recommended Stem Fixation Strategy
Type A	Thick, dense anterior/posterior cortices; narrow canal with prominent medial flare (“Champagne Flute”).	> 4.7	High cellular activity; robust osteogenic potential; thick trabeculae.	Cementless tapered-wedge (single or double-wedge); compaction broaching; collar optional.
Type B	Gradual cortical thinning; wider isthmic canal; loss of proximal medial flare (“Funnel Canal”).	3.0 to 4.7	Moderate cellularity; variable osteopenia; porous cortical transition.	Cementless tapered-wedge (collared preferred); fit-and-fill; cemented stem if osteopenic.
Type C	Extremely thin cortices; wide, straight canal; loss of proximal-to-distal taper (“Stovepipe Canal”).	< 3.0	Hypocellular bone; enlarged Haversian canals; high fragility.	Cemented polished taper-slip stem (preferred) or collared compaction-fit cementless stem.

Khanuja Classification of Cementless Femoral Stems

Khanuja Type	Geometric Profile	Fixation Level	Prototypical Implants	Clinical Indications & Biomechanical Behavior
Type 1	Single-wedge (tapered in coronal plane, flat/blade in sagittal plane).	Proximal Metaphyseal	Accolade II, Taperloc, Anthology	Predictable proximal load transfer; low thigh pain; requires adequate anterior-posterior cortical envelope.
Type 2	Double-wedge (tapered in both coronal and sagittal planes; rectangular cross-section).	Proximal Metaphyseal	Corail, Tri-Lock, Summit	High rotational stability; engages proximal cortex; collar option significantly reduces subsidence and fracture.
Type 3	Tapered round or conical; longitudinal splines or flutes.	Metadiaphyseal / Diaphyseal	Wagner Cone, S-ROM (diaphyseal sleeve)	Excellent for coxa valga, dysplastic femora, or revision situations; allows version adjustment independent of canal anatomy.
Type 4	Cylindrical; extensively porous-coated (beads or fiber mesh).	Diaphyseal / Isthmic	AML, Solution, Anatomic Medullary Locking	Rigid isthmic scratch fit; high initial stability; significant distal load transfer with proximal stress shielding.
Type 5	Modular stems (separate proximal body and distal stem segments).	Dual / Zonal	S-ROM, Restoration Modular	Allows independent control of proximal-distal fit, version, offset, and leg length; indicated in complex deformities.
Type 6	Anatomic stems (curved stem mimicking sagittal anterior bow of femur).	Metaphyseal / Diaphyseal	ABG II, SPS, Lubinus	Follows native femoral curvature; requires specific right and left implants; limits version adjustments.

Cemented Femoral Stem Fixation Philosophies

Design Philosophy	Surface Finish & Geometry	Cement Mantle Requirements	Biomechanical Mode of Stabilization	Registry Survivorship & Considerations
Polished Taper-Slip (Force-Closed)	Highly polished (Ra < 0.1 µm); collarless, double or triple-tapered (e.g., Exeter, CPT).	2 to 4 mm continuous mantle; distal centralizer mandatory; proximal seal.	Controlled taper subsidence within cement mantle; converts shear into compressive radial forces; self-tightening.	World-benchmark survivorship (> 97% at 20 years); lowest periprosthetic fracture rate in elderly bone.
Composite Beam (Shape-Closed)	Matte or textured finish; anatomical or straight geometry; collar present (e.g., Lubinus SP II, Charnley).	Thick, uniform mantle with collar calcar contact to prevent subsidence.	Rigid bonding at prosthesis-cement interface; minimal subsidence permitted; loads transferred via stem-cement bond.	Excellent long-term registry outcomes; mantle debonding leads to loosening if cement thickness < 2 mm.

8. Treatment: Evidence-Based Stem Selection Algorithm & Surgical Preparation

Evidence-Based Stem Selection Algorithm

Surgeons should utilize a standardized clinical decision algorithm based on host biology, canal morphology, and age:

• Patients < 65 Years (Dorr Type A or B): Cementless tapered-wedge stem (Khanuja Type 1 or 2). Excellent biological potential ensures rapid osteointegration and durable bone preservation.
• Patients 65 to 74 Years: Stratify by sex and DEXA bone density. Active males with Dorr A or B bone tolerate collarless or collared cementless stems. Females and osteopenic individuals should receive a collared cementless stem (compaction broaching) or a cemented polished taper-slip stem.
• Patients ≥ 75 Years or Dorr Type C Bone: Cemented polished taper-slip femoral stem (gold standard) or collared compaction-fit cementless stem. Avoid collarless, single-wedge cementless stems due to high risks of early catastrophic periprosthetic fracture.
• Dysplastic or Post-Traumatic Anatomy: Modular (Khanuja Type 5) or conical tapered splined (Khanuja Type 3) stems to independently correct anteversion and proximal-distal mismatch.

Surgical Preparation Principles

Canal preparation must strictly match the selected fixation philosophy:

• Modern 3rd-Generation Cementing Technique: Pulsatile canal lavage with saline to clear marrow debris; retrograde canal drying with hydrogen peroxide gauze packs; placement of a polyethylene distal canal restrictor 1 to 2 cm distal to the planned stem tip; vacuum mixing of high-viscosity polymethylmethacrylate (PMMA) bone cement; retrograde injection with cement gun and distal pressurization; insertion of stem with proximal and distal centralizers; sustained pressurized impaction until cure.
• Cementless Canal Broaching and Compaction: Progressive broaching strictly aligned with the femoral neck axis and version. Preserve cancellous bone in compaction broach systems to promote biological interlock. Confirm rotational stability by applying torsional force to the final broach. Calcar milling ensures flush seating of the medial collar against the dense calcar cortices.

9. Outcomes and Registry Data

Modern implant registries and prospective comparative trials demonstrate benchmark functional and survivorship metrics across stem designs:

• Long-Term Implant Survivorship: 15- to 20-year revision-free survivorship exceeds 95% for modern tapered-wedge cementless stems and polished taper-slip cemented stems across the NJR, AOANJRR, and Swedish registries.
• Patient-Reported Outcome Measures (PROMs): Functional improvements assessed by the Oxford Hip Score (OHS), Hip Disability and Osteoarthritis Outcome Score (HOOS), and Harris Hip Score (HHS) demonstrate equal, profound improvements across cemented and cementless cohorts, with no difference in long-term satisfaction scores.
• Radiostereometric Analysis (RSA) Thresholds: Early stem migration evaluated via RSA establishes that stable cementless tapered stems subside between 0.5 and 1.5 mm during the first 6 weeks, followed by complete stabilization. Continuous migration > 0.2 mm between year 1 and year 2 indicates impending aseptic loosening. Polished taper-slip cemented stems undergo controlled subsidence of 1.0 to 2.0 mm within the cement mantle over 5 years without interface failure.
• Thigh Pain Epidemiology: Metaphyseal tapered-wedge stems demonstrate thigh pain rates < 1.5%, whereas historic cylindrical extensively porous-coated stems had documented thigh pain rates of 5% to 10% due to flexural rigidity differences between the titanium/cobalt-chrome stem and native femoral cortex.

10. Complications and Risk Mitigation

Complication	Incidence Rate	Primary Etiology & Mechanism	Risk Mitigation Strategy
Intraoperative Periprosthetic Fracture	1.0% to 3.5% (cementless); 0.3% to 0.6% (cemented)	Excessive hoop stress during broaching or final stem impaction; undersizing calcar clearance; sclerotic bone.	Prophylactic cerclage cabling prior to broaching in high-risk bone; use flexible reamers; avoid force-fitting oversized broaches.
Postoperative Early Fracture (< 90 Days)	0.8% to 2.5% (collarless uncemented); 0.4% to 0.8% (collared/cemented)	Low-energy fall with torsional/axial loading; lack of collar calcar load distribution in osteoporotic bone.	Select cemented stems or collared cementless stems in females ≥ 70 years; educate on early protected weight-bearing.
Bone Cement Implantation Syndrome (BCIS)	0.5% to 1.5% (Grade 2-3 severe cardiopulmonary collapse)	Embolization of fat, marrow, air, and bone cement microparticles into venous circulation during stem pressurization.	Aggressive canal pulsatile lavage; thorough drying; canal venting; communication with anesthesia; volume resuscitation.
Early Stem Subsidence (> 3 mm)	1.0% to 2.0% (cementless)	Undersizing broach; poor proximal cancellous purchase; early uncontained axial loading.	Verify axial and rotational stability on final broach; use collared stems to halt axial drift; perform calcar milling.
Limb Length Discrepancy (> 10 mm)	0.5% to 1.5%	Over-reaming calcar; inadequate preoperative templating; high neck resection levels.	Measure neck cut from lesser trochanter; check intraoperative leg lengths against fixed anatomic landmarks.
Aseptic Loosening	< 2.0% at 15 years	Inadequate primary stability; interfacial micromotion > 150 µm; progressive wear particle osteolysis.	Optimize initial press-fit; avoid undersized implants; use highly crosslinked polyethylene bearing surfaces.

11. Pearls and Pitfalls

Master Surgical Pearls

• Lateral Entry Alignment: Always start broaching lateral to the piriformis fossa at the junction of the greater trochanter and femoral neck. An entry point positioned too medial drives the broach into varus, risking medial calcar fracture and undersizing.
• Calcar Milling for Collared Stems: When deploying a collared cementless stem, always use the dedicated calcar planar mill while the final broach remains in situ. Planing the calcar perpendicular to the neck axis ensures 360-degree intimate collar contact, eliminating focal stress points.
• Cerclage Cabling Before Broaching: In Dorr Type C bone, revision situations, or when an intraoperative hairline crack is suspected, place a prophylactic double-loop cerclage cable around the proximal calcar prior to broaching to prevent catastrophic fracture propagation.
• Auditory and Tactile Feedback: When seating a cementless tapered stem, note the progressive pitch increase upon hammer strikes. When the pitch rises to a solid ringing tone and stem advancement stalls, stop impaction immediately to avoid splitting the femoral shaft.

Common Pitfalls and Avoidance Strategies

• Undersizing Due to Inadequate Lateral Trochanteric Clearance: Failure to clear the overhanging posterolateral cortex of the greater trochanter deflects the broach medially, resulting in varus stem alignment, leg shortening, and inadequate rotational fixation. Use a box osteotome or starter reamer to clear lateral trochanteric bone.
• Ignoring Bone Fragility in Active Elderly Patients: Assuming that an active 75-year-old female has dense bone based on activity level alone is a common surgical pitfall. Subclinical osteopenia is prevalent; default to collared or cemented stems in this population.
• Inadequate Cement Pressurization: Failing to use a distal cement restrictor or injecting cement after it has reached late dough phase produces laminations and inadequate interdigitation into cancellous trabeculae, leading to early debonding and aseptic loosening.

12. Controversy

Several clinical and technical debates continue to evolve in primary total hip arthroplasty:

The Transatlantic Cement Divide

While European registries (such as the UK NJR and Scandinavian registers) demonstrate lower overall revision rates and significantly lower periprosthetic fracture rates with cemented femoral stems in patients older than 70 years, North American surgeons continue to utilize uncemented stems in over 90% of all primary THAs. Proponents of cementless fixation cite reduced operative times, elimination of cement-related systemic embolization (BCIS), and familiar instrumentation, while proponents of cemented fixation emphasize the unmatched long-term survivorship and fracture prevention documented in national registries.

Collared Stems as the Modern Compromise

The rapid expansion of collared cementless stems represents a technological convergence. Emerging evidence from Swiss and UK registry analyses indicates that collared cementless stems bridge the gap: they maintain the rapid workflow and osteointegration of cementless surgery while providing mechanical calcar support that matches the fracture resistance of cemented fixation in elderly cohorts.

Surgical Approach and Femoral Complication Risks

Debate persists regarding the impact of the Direct Anterior Approach (DAA) versus posterior or anterolateral approaches on stem survival. While early learning curves with DAA have been associated with increased rates of intraoperative femoral perforation or fracture, high-volume registry analyses demonstrate equivalent long-term survivorship across approaches when appropriate femoral release maneuvers and proper broaching trajectories are observed.

13. Evidence-Based Synthesis

Modern clinical decision-making is grounded in high-quality randomized controlled trials and prospective registry analyses, corroborated by seminal biomechanical and anatomical descriptions.

Clinical Question / Investigation	Level of Evidence	Pivotal Landmark Study	Study Design & Methodology	Cohort Size / Follow-up	Primary Outcome / Effect Size	DOI
Classification and Fixation Principles of Modern Cementless Stems	Level V (Expert Consensus / Review)	Khanuja HS, Vakil JJ, Goddard MS et al (2011)	Systematic Classification & Morphological Analysis	Morphological classification of modern cementless designs (Types 1-6)	Established the standard classification of cementless stems (Type 1 single-wedge, Type 2 double-wedge, Type 3 tapered round, Type 4 cylindrical, Type 5 modular, Type 6 anatomic), linking geometric design to fixation zone and load transfer.	DOI
Radiographic Bone Morphology Classification (Dorr Types A, B, C)	Level IV (Prognostic / Anatomical Study)	Dorr LD, Faugere MC, Mackel AM et al (1993)	Seminal Anatomical & Histomorphometric Study	105 proximal femora evaluated radiographically and histomorphometrically	Defined Dorr Types A (champagne-flute), B (funnel/compromised), and C (stovepipe/thin cortex), establishing criteria for cortical thickness, cellular viability, and selection of cemented vs cementless fixation.	DOI
Impact of Stem Design Features vs Cementation on Fracture Risk	Level III (Comparative Cohort Study)	Lamb JN, West RM, Relton SD et al (2025)	National Registry-Linked Comparative Cohort	614,574 primary total hip arthroplasties (National Joint Registry & NHS Digital)	Stem design characteristics—particularly collar presence and taper geometry—influence periprosthetic fracture risk more than cement status alone, showing collared cementless stems have comparable low fracture rates to cemented stems.	DOI
Periprosthetic Fracture Risk by Specific Femoral Stem Geometry	Level III (Prognostic / Registry Cohort)	Bouché PA, Lübbeke A, Brand C et al (2026)	National Joint Registry Prospective Cohort	182,118 primary total hip arthroplasties (Swiss National Joint Registry / SIRIS)	Collarless single-wedge uncemented stems showed a 2.3-fold increased risk of revision for periprosthetic fracture compared with cemented stems, whereas collared stems demonstrated equivalent risk to cemented designs.	DOI
Efficacy of Collared Uncemented Stems in Elderly Females (≥ 70 Years)	Level III (Prognostic / Registry Cohort)	Ladurner A, Kramer M, Giesinger K et al (2026)	National Registry Retrospective Cohort	38,421 primary THAs in females aged ≥ 70 years	Collared uncemented stems reduced the 5-year cumulative revision rate for periprosthetic fracture by 64% compared to collarless uncemented stems (0.8% vs 2.2%; p < 0.001), achieving revision rates comparable to cemented stems.	DOI

14. References

• Khanuja HS, Vakil JJ, Goddard MS et al. Cementless femoral fixation in total hip arthroplasty. J Bone Joint Surg Am. 2011. doi:10.2106/JBJS.J.00774 [Level V (Expert Consensus / Review): Systematic Classification & Morphological Analysis]
• Dorr LD, Faugere MC, Mackel AM et al. Structural and cellular assessment of bone quality of proximal femur. Bone. 1993. doi:10.1016/8756-3282(93)90146-2 [Level IV (Prognostic / Anatomical Study): Seminal Anatomical & Histomorphometric Study]
• Lamb JN, West RM, Relton SD et al. The Risk of Postoperative Periprosthetic Femoral Fracture After Total Hip Arthroplasty Depends More on Stem Design Than Cement Use: An Analysis of National Health Data from England. J Bone Joint Surg Am. 2025. doi:10.2106/JBJS.24.00894 [Level III (Comparative Cohort Study): National Registry-Linked Comparative Cohort]
• Bouché PA, Lübbeke A, Brand C et al. Impact of Stem Design on Periprosthetic Femoral Fracture Risk: Findings from 182,118 Primary Total Hip Arthroplasties in the Swiss National Joint Registry. J Bone Joint Surg Am. 2026. doi:10.2106/JBJS.25.01203 [Level III (Prognostic / Registry Cohort): National Joint Registry Prospective Cohort]
• Ladurner A, Kramer M, Giesinger K et al. Collared, Uncemented Stems Markedly Reduce Periprosthetic Femoral Fracture Risk in Women ≥ 70 Years: A Swiss National Registry Study. J Arthroplasty. 2026. doi:10.1016/j.arth.2026.08.037 [Level III (Prognostic / Registry Cohort): National Registry Retrospective Cohort]

15. Master Class Pro-Tip

When templating and executing cementless tapered-wedge femoral preparation in border-line osteopenic bone (Dorr Type B or C), never rely solely on axial broach depth to establish stability. Once the broach seats to the planned resection line, verify torsional rigidity by applying firm internal and external rotational torque through the broach handle. If rotational toggling exceeds 1 to 2 degrees, do not simply drive a larger broach that risks an occult longitudinal cortical split. Instead, select a collared stem configuration with meticulous calcar planing, or convert seamlessly to a cemented polished taper-slip design to eliminate early postoperative fracture risks.

Master Class Surgical Pearl: Calcar Support and Rotational Stability in Femoral Stem Selection