Classification system
Neer Classification
Neer Classification of Proximal Humerus Fractures
The Neer classification sorts proximal humerus fractures into one-, two-, three- and four-part injuries by counting how many of the four anatomical segments — articular surface, greater tuberosity, lesser tuberosity and shaft — are displaced more than 1 cm or angulated more than 45°, with separate categories for fracture-dislocations and articular surface fractures.
What the Neer category means
Neer scores run from 1 to 4, where a lower score is better. The bands below are conventional reporting categories, not diagnostic cut-offs.
- Minimally displaced1–1
Usually treated non-operatively with early mobilisation.
- Two-part2–2
Treatment depends on which segment is displaced and on patient demand; many two-part surgical neck fractures are still managed non-operatively.
- Three-part3–3
Unstable; reduction and fixation are usually considered in patients fit for surgery.
- Four-part4–4
High risk of avascular necrosis; arthroplasty is often preferred in older patients, except in the valgus-impacted variant.
Published criteria and reliability
The published cut-offs that define this instrument, and the measured agreement between observers using it. Each is reported with the population it was derived in.
| Type | Value | Subscale | Population | Follow-up | Source |
|---|---|---|---|---|---|
| Criterion | Displacement greater than 1 cm or angulation greater than 45° defines a part | — | Adults, plain radiographs or CT | — | Neer CS 2nd 1970 |
| Criterion | Interobserver kappa 0.48–0.52; intraobserver mean kappa 0.66. Collapsing the system from 16 to 6 categories did not significantly improve either | — | Five observers (shoulder specialist, traumatologist, skeletal radiologist, two residents) reading 50 proximal humerus radiographs twice | — | Sidor ML 1993 |
| Criterion | Adding CT to radiographs left interobserver reproducibility unchanged (kappa 0.52 to 0.50); intraobserver reliability rose slightly (0.64 to 0.72) | — | Orthopaedic surgeons classifying proximal humeral fractures on radiographs with and without CT | — | Bernstein J 1996 |
Criterion is a published cut-off, definition or performance figure belonging to a classification or decision rule — it is not a change score and should not be read as one.
How the score is calculated
Stated in full so the calculation can be independently checked, and reproduced by hand if needed.
The proximal humerus is divided into four segments, following the epiphyseal lines: the articular segment (anatomical neck), the greater tuberosity, the lesser tuberosity and the shaft (surgical neck). Each segment is judged displaced only if it is separated from its neighbours by more than 1 cm or angulated more than 45°. The number of parts equals the number of displaced segments plus one: no displaced segment is a one-part fracture however many fracture lines are present, one displaced segment is a two-part fracture, two displaced segments a three-part fracture, and three or more a four-part fracture. Neer’s original paper arranged these in six groups — I minimal displacement, II anatomical neck, III surgical neck, IV greater tuberosity, V lesser tuberosity and VI fracture-dislocation — each subdivided by part count, and described articular surface fractures (head-splitting and impression) separately.
Missing data
All four segments must be judged before a part count is reported; an unassessed segment is not treated as undisplaced. The dislocation and articular surface field may be left blank, in which case the result carries a note that those patterns have not been excluded.
Instrument profile
- Developer
- Charles S. Neer II
- Institution
- Columbia-Presbyterian Medical Center, New York
- First published
- 1970
- Items
- 5
- Response format
- Segment-by-segment radiographic assessment of displacement
- Score range
- 1 to 4
- Direction
- Lower score = better
- Completion time
- About 2 minutes
- Age range
- Adults; the fracture is commonest in women over 65 with osteoporotic bone
- Regions
- Shoulder
- Conditions
- Proximal humerus fracture, Greater tuberosity fracture, Surgical neck fracture, Shoulder fracture-dislocation, Fragility fracture
- Procedures
- Open reduction and internal fixation, Locking plate fixation, Intramedullary nailing, Hemiarthroplasty, Reverse total shoulder arthroplasty
- Validity
- The part count tracks the loss of soft-tissue attachment to the articular segment, which is why it predicts avascular necrosis reasonably well at the extremes — one-part fractures rarely develop it, four-part fractures often do.
- Reliability
- Reliability is the system’s recognised weakness, and it is not easily engineered away: collapsing the sixteen categories to six did not significantly improve either interobserver reliability or intraobserver reproducibility in the assessment by Sidor and colleagues, and adding CT did not improve interobserver agreement in the study by Bernstein and colleagues. The distinction that carries most of the management decision — minimally displaced against displaced — is the coarsest one, and is correspondingly the one observers agree on most readily.
Normative values
Reference values from published cohorts, for comparison against the score you calculated.
| Population | Age | Mean | SD |
|---|---|---|---|
| All proximal humerus fractures presenting to hospital | — | Approximately 80–85% are minimally displaced (one-part) | — |
| All adult fractures | — | Proximal humerus fractures account for roughly 5–6% of adult fractures and are the third commonest osteoporotic fracture | — |
When to use the Neer
Well suited to
- Describing and communicating a proximal humerus fracture on a trauma radiograph series or CT.
- Deciding between non-operative treatment, fixation and arthroplasty, where the part count is one input alongside age, bone quality and head perfusion.
- Reporting fracture severity in trials and registries, usually alongside the AO/OTA code.
Limitations and poor fits
- Physeal fractures in children and adolescents — use the Salter-Harris system, and treat remodelling potential as the dominant consideration.
- As the sole predictor of head viability: the Hertel criteria, in particular a posteromedial metaphyseal head extension shorter than 8 mm and a disrupted medial hinge, predict ischaemia better than the part count.
- For isolated greater tuberosity fractures, where the clinically relevant displacement threshold is far smaller than Neer’s 1 cm.
- Where only the anteroposterior view is available — a posterior fracture-dislocation cannot be excluded on that view alone.
Neer compared with other instruments
Instruments measuring a related construct, with the practical difference between them.
| Instrument | Items | Range | What it adds |
|---|---|---|---|
| AO/OTA | 3 | 1–3 | The AO/OTA classification gives every fracture an alphanumeric code in which the first digit is the bone, the second the segment and the letter the fracture type — extra-articular, partial articular or complete articular in an end segment, and simple, wedge or multifragmentary in a shaft — so that 32-A is a simple femoral shaft fracture and 43-C a complete articular pilon fracture. |
| Constant Score | 10 | 0–100 | The Constant-Murley score is a 100-point clinician-administered shoulder assessment combining 35 subjective points for pain and daily activities with 65 objective points for measured range of motion and abduction strength, where 100 represents a normal, pain-free shoulder. |
| Oxford Shoulder Score | 12 | 0–48 | The Oxford Shoulder Score is a 12-item patient-reported questionnaire about shoulder pain and everyday function over the past four weeks, each item scored 0 to 4 and summed to a total of 0 to 48 in which 48 represents the best possible shoulder — it is licensed by Oxford University Innovation, so the item wording is not reproduced here. |
Copyright and permitted use
Published openly because it is the question every clinician and researcher asks before using an instrument, and almost nobody answers it.
A published radiographic classification system. No licence is required to apply, reproduce or describe it.
References
- Neer CS 2nd. Displaced proximal humeral fractures. I. Classification and evaluation. Journal of Bone and Joint Surgery (American). 1970.
- Neer CS 2nd. Displaced proximal humeral fractures. II. Treatment of three-part and four-part displacement. Journal of Bone and Joint Surgery (American). 1970.
- Sidor ML, Zuckerman JD, Lyon T, Koval K, Cuomo F, Schoenberg N. The Neer classification system for proximal humeral fractures: an assessment of interobserver reliability and intraobserver reproducibility. Journal of Bone and Joint Surgery (American). 1993.
- Bernstein J, Adler LM, Blank JE, Dalsey RM, Williams GR, Iannotti JP. Evaluation of the Neer system of classification of proximal humeral fractures with computerized tomographic scans and plain radiographs. Journal of Bone and Joint Surgery (American). 1996.
- Neer CS 2nd. Four-segment classification of proximal humeral fractures: purpose and reliable use. Journal of Shoulder and Elbow Surgery. 2002.
- Court-Brown CM, Caesar B. Epidemiology of adult fractures: a review. Injury. 2006.
Editorial status
This page has not yet been signed off by a named clinical reviewer. The scoring logic is stated in full above so it can be independently verified, and every threshold is traceable to its source. See our editorial methodology.