This narrative review examines the Pauwels classification for femoral neck fractures — the first biomechanical classification system for this injury, introduced in 1935. It addresses three unresolved questions: how to measure the Pauwels angle reliably, whether the classification predicts complications, and what fixation best treats Type III fractures in young adults.
When you classify a femoral neck fracture by Pauwels type, you need to know two things: the correct thresholds and the limitations of the measurement. The thresholds are 30° and 50° (not 30° and 70° — the 70° figure is a decades-old misquotation of Pauwels' original work). Type III starts at 50°.
The measurement is inherently unreliable. An inter-observer kappa of 0.31 means two surgeons looking at the same film will often disagree on type — because leg position during the radiograph changes the angle. This is a known, unfixed problem in the classification, and it is why the literature on Pauwels type vs. complications is so heterogeneous.
For treatment, the clinical decision point is Pauwels type in young adults. Types I and II, where compression dominates, can be managed with three parallel cannulated screws. Type III, where shear dominates, likely requires a fixed-angle construct (dynamic hip screw, proximal femoral locking plate) to resist varus collapse — though the evidence comes mostly from biomechanical studies, and the single largest clinical series was underpowered to show a statistically significant difference in non-union rates.
This narrative review examines the Pauwels classification for femoral neck fractures — the first biomechanical classification system for this injury, introduced in 1935. It addresses three unresolved questions: how to measure the Pauwels angle reliably, whether the classification predicts complications, and what fixation best treats Type III fractures in young adults.
When you classify a femoral neck fracture by Pauwels type, you need to know two things: the correct thresholds and the limitations of the measurement. The thresholds are 30° and 50° (not 30° and 70° — the 70° figure is a decades-old misquotation of Pauwels' original work). Type III starts at 50°.
The measurement is inherently unreliable. An inter-observer kappa of 0.31 means two surgeons looking at the same film will often disagree on type — because leg position during the radiograph changes the angle. This is a known, unfixed problem in the classification, and it is why the literature on Pauwels type vs. complications is so heterogeneous.
For treatment, the clinical decision point is Pauwels type in young adults. Types I and II, where compression dominates, can be managed with three parallel cannulated screws. Type III, where shear dominates, likely requires a fixed-angle construct (dynamic hip screw, proximal femoral locking plate) to resist varus collapse — though the evidence comes mostly from biomechanical studies, and the single largest clinical series was underpowered to show a statistically significant difference in non-union rates.