High-yield overview
4 typesI valgus impacted, II complete undisplaced, III partial displacement, IV full displacement
I and IIundisplaced group — lower AVN and nonunion risk
III and IVdisplaced group — higher AVN (up to 30 percent) and nonunion risk
Dichotomyundisplaced versus displaced used for treatment decisions and reliability
Critical Must-Knows
- Garden classifies intracapsular femoral neck fractures by the degree of displacement on the anteroposterior radiograph and guides urgency of reduction, fixation method and counselling on complication risk.
- Type I is valgus-impacted or incomplete; Type II is complete but undisplaced; Type III shows partial displacement; Type IV is fully displaced with no cortical contact.
- Undisplaced fractures (I and II) are usually fixed with cannulated screws or a sliding hip screw; displaced fractures (III and IV) in younger patients need urgent open or closed reduction and internal fixation, while older patients often receive arthroplasty.
- Displacement increases the risk of avascular necrosis and nonunion because the retinacular vessels are stretched or torn; the risk rises sharply once the fracture is displaced.
The classification examiners actually use
The Garden system is the standard language for intracapsular neck of femur fractures, but inter-observer reliability is only moderate for the four-type version. In practice and in most exam answers, fractures are dichotomised into undisplaced (Garden I-II) versus displaced (Garden III-IV) because this binary split drives treatment and has better reproducibility. Always state both the full Garden type and the clinical dichotomy when describing a fracture.
The Garden Classification System
The Garden classification is based on the appearance of the femoral head and neck on the anteroposterior radiograph. It describes the position of the capital fragment relative to the acetabulum and the degree of cortical continuity.
| Type | Description | Key Radiographic Signs | Displacement Status |
|---|---|---|---|
| I | Valgus-impacted or incomplete | Head tilted into valgus on neck; trabeculae still aligned or slightly impacted; cortical break incomplete | Undisplaced |
| II | Complete but undisplaced | Full fracture line visible across neck; head and neck remain aligned; no varus or valgus tilt | Undisplaced |
| III | Partially displaced | Head tilted into varus; partial cortical contact remains; fracture line oblique | Displaced |
| IV | Fully displaced | No cortical contact; head free in acetabulum or rotated; shaft displaced proximally and externally rotated | Displaced |
Mnemonic
Incomplete • Complete • Partial • FreeGarden I to IV progression
Clinical Pearl
The critical distinction is between undisplaced (I-II) and displaced (III-IV). Undisplaced fractures preserve the retinacular blood supply far better; once displacement occurs the superior retinacular vessels are at risk and avascular necrosis becomes a real threat.
Garden Types and Management Implications
Management decisions are driven by patient age, comorbidities, fracture displacement and the viability of the femoral head.
| Garden Type | Patient Group | Preferred Treatment | Key Considerations |
|---|---|---|---|
| I or II (undisplaced) | Any age | Internal fixation — cannulated screws or sliding hip screw | Preserve the head; low AVN risk; allow early mobilisation |
| III or IV (displaced) | Young, fit (< 60-65 years) | Urgent closed or open reduction and internal fixation | Within 6-12 hours ideally; aim for anatomical reduction; higher AVN risk |
| III or IV (displaced) | Older, frail (> 75-80 years) | Cemented hemiarthroplasty or total hip arthroplasty | Avoid prolonged surgery; allow immediate full weight-bearing; lower re-operation rate than fixation |
Caution
In a young patient with a displaced Garden III or IV fracture, time is critical. Every hour of delay increases the risk of avascular necrosis. Reduce anatomically, compress the fracture, and protect the reduction with a sliding hip screw or cannulated screws placed in an inverted-triangle configuration.
Mnemonic
Undisplaced fix • Displaced young reduce • Displaced old replaceTreatment by displacement
Limitations and Reliability
- The four-type Garden system has only moderate inter-observer reliability; many surgeons cannot consistently distinguish Type II from Type III on plain radiographs.
- The binary split into undisplaced versus displaced is far more reproducible and is what most guidelines and registries actually use for outcome reporting.
- Garden does not account for posterior comminution, which is visible on the lateral radiograph and increases the risk of fixation failure.
- The classification is purely radiographic and does not incorporate patient factors such as bone quality, comorbidities or time to presentation.
- Modern CT and MRI can detect occult Garden I fractures and assess femoral head perfusion, but the Garden label itself remains a plain-film tool.
Evidence Base
Evidence
Garden classification of femoral neck fractures: inter-observer reliability
Thomsen NO, Jensen CM, Skovgaard N, et al. • Int Orthop (1996)
Key Findings:
- Moderate kappa values for the four-type Garden classification among orthopaedic surgeons
- Agreement improved substantially when fractures were grouped as undisplaced versus displaced
- Posterior comminution on the lateral view was an important but under-recognised prognostic factor
Clinical implication: Supports the routine use of the binary undisplaced/displaced dichotomy in clinical practice and exam answers.
Limitation: Single-centre study; did not correlate classification with actual clinical outcomes.
Source: Int Orthop 1996;20(5):326-9
Evidence
Internal fixation versus arthroplasty for displaced femoral neck fractures in the elderly
Parker MJ, Gurusamy K • Cochrane Database Syst Rev (2006)
Key Findings:
- Meta-analysis showed lower re-operation rate with arthroplasty than with internal fixation for displaced fractures in older patients
- Functional outcomes similar at two years but arthroplasty avoided the complications of nonunion and AVN
- Cemented hemiarthroplasty offered the best balance of low re-operation and acceptable morbidity
Clinical implication: Provides level-1 evidence that older patients with Garden III or IV fractures should usually receive arthroplasty rather than attempted fixation.
Limitation: Heterogeneous trials; variable implant designs and surgical techniques.
Source: Cochrane Database Syst Rev 2006;(3):CD001706
Evidence
Does Garden type I incomplete femoral neck fracture really exist in older adults? To evaluate the stability and consistency of Garden classification.
Cai Z, Zhang Z, Ren L, et al. • BMC Surg (2022)
Key Findings:
- Garden classification shows only moderate inter-observer reliability even among experienced surgeons
- Many apparent Garden I fractures are complete on CT, questioning the existence of truly incomplete fractures in osteoporotic bone
- Simplifying to undisplaced versus displaced improves both reliability and clinical utility
Clinical implication: Reinforces that the binary Garden I-II vs III-IV split is more reliable and clinically relevant than the four-type system.
Limitation: Single-centre study; CT used selectively for confirmation.
Source: BMC Surg 2022;22(1):276
Evidence
Femoral neck fracture: the reliability of radiologic classifications.
Cazzato G, Oliva MS, Masci G, et al. • BMC Musculoskelet Disord (2022)
Key Findings:
- Garden classification demonstrated only fair to moderate inter-observer agreement (kappa approximately 0.4-0.6)
- The undisplaced versus displaced dichotomy showed better reproducibility than the four individual Garden types
- Similar limitations in reliability were observed with the AO/OTA classification
Clinical implication: Confirms that Garden's four-type system has limited reliability; the clinical dichotomy is preferred for treatment algorithms and research.
Limitation: Based on radiographs alone; no direct correlation with patient outcomes.
Source: BMC Musculoskelet Disord 2022;22(Suppl 2):1063
Exam Viva
Practise clinical reasoning and management decisions out loud
Viva scenarioStandard
Clinical prompt
“A 68-year-old woman falls at home and sustains a left femoral neck fracture. The anteroposterior radiograph shows a complete fracture line with the head tilted into slight varus and partial cortical contact. What is the Garden classification and how would you manage her?”
Practical approach
This is a Garden Type III fracture — partially displaced. In a 68-year-old patient the standard management is cemented hemiarthroplasty or total hip arthroplasty depending on her activity level and acetabular wear. I would confirm the classification on both anteroposterior and lateral views, stage her medically, give thromboprophylaxis and operate within 24 hours. The lateral radiograph is essential to assess posterior comminution, which would further support replacement over fixation.
Key clinical points
Correctly identify Garden III (partial displacement, varus tilt, some contact)
Recognise that age and displacement favour arthroplasty over fixation
Mention the importance of the lateral view for posterior comminution
Emphasise timely surgery and medical optimisation
Common pitfalls
Misclassifying as Garden II because the fracture is not fully displaced
Suggesting cannulated screws in an older patient with a displaced fracture
Forgetting to mention the lateral radiograph
Further questions
“How would your management change if she were 45 years old?”
“What is the risk of avascular necrosis after fixation of a Garden III fracture?”
“Why is posterior comminution important?”
Viva scenarioAdvanced
Clinical prompt
“A 52-year-old man is brought in after a high-energy road-traffic collision. He has a displaced femoral neck fracture that you classify as Garden IV. Outline your operative plan and the key discussion points for consent.”
Practical approach
Garden IV indicates complete displacement with no cortical contact; the retinacular vessels are at high risk. In a fit 52-year-old I would plan urgent closed reduction under image intensifier, aiming for an anatomical reduction, followed by internal fixation with a sliding hip screw or three cannulated screws in an inverted-triangle configuration. I would obtain informed consent covering a 20-30 percent risk of avascular necrosis, possible nonunion, the need for later arthroplasty, and the importance of immediate postoperative weight-bearing restrictions if reduction is imperfect. If closed reduction fails I would proceed to open reduction via an anterolateral approach.
Key clinical points
State Garden IV explicitly and link displacement to vascular risk
Urgent reduction within 6-12 hours in a young patient
Anatomical reduction and stable fixation are mandatory
Consent must cover AVN, nonunion and possible future surgery
Common pitfalls
Delaying surgery for further imaging when the diagnosis is clear
Accepting a non-anatomical reduction
Using a single cannulated screw or DHS without anti-rotation control
Further questions
“What radiographic signs confirm an anatomical reduction?”
“How does the choice of implant change if there is posterior comminution?”
“What is the role of capsulotomy or decompression in this setting?”
Exam day cheat sheet
Garden Classification — Exam Cheat Sheet
The four Garden types
- Type I: valgus-impacted or incomplete — head tilted into valgus, trabeculae aligned
- Type II: complete but undisplaced — full fracture line visible, head and neck aligned
- Type III: partially displaced — varus tilt, some cortical contact remains
- Type IV: fully displaced — no cortical contact, head free or rotated
Clinical dichotomy that actually matters
- Undisplaced (Garden I-II): fix with screws or sliding hip screw in almost all patients
- Displaced (Garden III-IV): young patient — urgent reduction and fixation; older patient — arthroplasty
- Displacement increases AVN risk from under 10 percent to 20-30 percent
- Always obtain and review the lateral radiograph for posterior comminution
Key exam points and pitfalls
- Reliability is moderate for four types; excellent for the binary undisplaced versus displaced split
- Garden does not replace clinical judgement — bone quality, comorbidities and time since injury all matter
- In young patients with displaced fractures, document the time of injury and aim for theatre within 6-12 hours
- Posterior comminution on the lateral view predicts loss of reduction even if the anteroposterior view looks acceptable