Subtrochanteric fractures are proximal femur fractures that occur between the lesser trochanter and a point 5cm distal to the lesser trochanter. This region of the femur experiences high compression and tensile forces, has less blood supply, has a dense cortex that is less prone to healing, and has a lot of deforming forces in the proximal fragment. They may occur in the elderly and young patients following low-energy or high-energy mechanisms, respectively. Treatment is usually operative.
Subtrochanteric fractures account for 10% of proximal femur fractures .
Russell-Taylor classification (historical classification based on whether the fracture would be amenable to a standard IM nail (type I) vs. a lateral fixed-angle device (type II)
Classification Description Type I No extension into the piriformis fossa Type II Extension into the greater trochanter with involvement of the piriformis fossa
Mechanism of injury
High-energy mechanism, e.g., MVA, in young patients
Low-energy mechanism, e.g., a fall from standing height in elderly patients
Deforming forces (proximal fragment)
Flexion by psoas
Abduction by gluteus medius and minimus
External rotation by short rotators
Patient history
Signs and symptoms
Hip and thigh pain
Inability to bear the wait
Pain with motion
Obvious deformity (shortening and varus alignment)
Skin tenting (due to flexion of the proximal fragment)
Investigations
X-ray (AP and lateral hip, AP pelvis, full-length femur, including knee joint)
Transverse tension component on the lateral side and oblique compression component on the medial side in bisphosphonate-related fractures
Indications for non-operative treatment
Non-ambulatory patient
Co-morbidities that make the patient unfit for surgery
Non-operative treatment
Rarely used due to strong deforming forces and inability to mobilize without surgery
Operative treatment
Intramedullary nailing (cephalomedullary)
Fixed angle plate
Complications
Varus or procurvatum malunion
Nonunion
Biochemistry
ACTH P: <80 ng/L ALT P: 5–35 U/L Albumin P: 35–50 g/L Aldosterone P: 100–500 pmol/L Alk. phosphatase P: 30–130 U/L α-Amylase P: 0–180 IU/dL α-Fetoprotein S: <10 kU/L Angiotensin II P: 5–35 pmol/L ADH P: 0.9–4.6 pmol/L AST P: 5–35 U/L Bicarbonate P: 24–30 mmol/L Bilirubin P: 3–17 μmol/L BNP P: <50 ng/L CRP P: <10 mg/L Calcitonin P: <0.1 mcg/L Calcium (ionized) P: 1.0–1.25 mmol/L Calcium (total) P: 2.12–2.60 mmol/L Chloride P: 95–105 mmol/L Cholesterol P: <5.0 mmol/L VLDL P: 0.128–0.645 mmol/L LDL P: <2.0 mmol/L HDL P: 0.9–1.93 mmol/L Cortisol AM P: 450–700 nmol/L Cortisol Midnight P: 80–280 nmol/L CK ♂ P: 25–195 U/L CK ♀ P: 25–170 U/L Creatinine P: 70–100 μmol/L Ferritin P: 12–200 mcg/L Folate S: 2.1 mcg/L FSH P: 2–8 U/L ♂; >25 menopause GGT ♂ P: 11–51 U/L GGT ♀ P: 7–33 U/L Glucose (fasting) P: 3.5–5.5 mmol/L Growth hormone P: <20 mu/L HbA1C (DCCT) B: 4–6% HbA1C (IFCC) B: 20–42 mmol/mol Iron ♂ S: 14–31 μmol/L Iron ♀ S: 11–30 μmol/L Lactate (venous) P: 0.6–2.4 mmol/L Lactate (arterial) P: 0.6–1.8 mmol/L LDH P: 70–250 U/L LH P: 3–16 U/L Magnesium P: 0.75–1.05 mmol/L Osmolality P: 278–305 mosmol/kg PTH P: 0.8–8.5 pmol/L Potassium P: 3.5–5.3 mmol/L Prolactin ♂ P: <450 U/L Prolactin ♀ P: <600 U/L PSA P: 0–4 mcg/mL Protein (total) P: 60–80 g/L Red cell folate B: 0.36–1.44 μmol/L Renin (erect) P: 2.8–4.5 pmol/mL/h Renin (recumbent) P: 1.1–2.7 pmol/mL/h Sodium P: 135–145 mmol/L TBG P: 7–17 mg/L TSH P: 0.5–4.2 mU/L T4 P: 70–140 nmol/L Free T4 P: 9–22 pmol/L TIBC S: 54–75 μmol/L Triglycerides P: 0.50–2.3 mmol/L T3 P: 1.2–3.0 nmol/L Troponin T P: <0.1 mcg/L Urate ♂ P: 210–480 μmol/L Urate ♀ P: 150–390 μmol/L Urea P: 2.5–6.7 mmol/L Vitamin B12 S: 0.13–0.68 nmol/L Vitamin D S: 50 nmol/L
Arterial Blood Gases
pH 7.35–7.45 PaCO₂ 4.7–6.0 kPa PaO₂ >10.6 kPa Base excess ±2 mmol/L
Urine
Cortisol (free) <280 nmol/24h Hydroxyindole acetic acid 16–73 μmol/24h Hydroxymethylmandelic acid 16–48 μmol/24h Metanephrines 0.03–0.69 μmol/mmol cr. Osmolality 350–1000 mosmol/kg 17-Oxogenic steroids ♂ 28–30 μmol/24h 17-Oxogenic steroids ♀ 21–66 μmol/24h 17-Oxosteroids ♂ 17–76 μmol/24h 17-Oxosteroids ♀ 14–59 μmol/24h Phosphate (inorganic) 15–50 mmol/24h Potassium 14–120 mmol/24h Protein <150 mg/24h Protein/creatinine ratio <3 mg/mmol Sodium 100–250 mmol/24h
Haematology
WCC 4.0–11.0 ×10⁹/L RBC ♂ 4.5–6.5 ×10¹²/L RBC ♀ 3.9–5.6 ×10¹²/L Hb ♂ 130–180 g/L Hb ♀ 115–160 g/L PCV ♂ 0.4–0.54 L/L PCV ♀ 0.37–0.47 L/L MCV 76–96 fL MCH 27–32 pg MCHC 300–360 g/L RDW 11.6–14.6% Neutrophils 2.0–7.5 ×10⁹/L (40–75%) Lymphocytes 1.0–4.5 ×10⁹/L (20–45%) Eosinophils 0.04–0.44 ×10⁹/L (1–6%) Basophils 0–0.10 ×10⁹/L (0–1%) Monocytes 0.2–0.8 ×10⁹/L (2–10%) Platelets 150–400 ×10⁹/L Reticulocytes 0.8–2.0% / 25–100 ×10⁹/L Prothrombin time 10–14 s APTT 35–45 s
Paediatric
Pulse Rate (bpm) Neonate 140–160 Infant <1yr 120–140 1–5 years 110–130 5–12 years 80–120 >12 years 70–100 Respiratory Rate (tachypnoea) 0–2 months ≥60/min 2–12 months ≥50/min 1–5 years ≥40/min >5 years ≥30/min Blood Pressure (mmHg) Term 65/45 1 year 75/50 4 years 85/60 8 years 95/65 10 years 100/70 Weight Formulas 3–12 months (a + 9)/2 kg 1–6 years 2a + 8 kg >6 years (7a − 5)/2 kg Haemoglobin (g/dL) Term newborn 13–20 1 month 11–18 2 months 10–15 1–2 years 10–13 >2 years 11–14 MUAC (6 months–5 years) Obese >17.5 cm Normal 13.5–17.4 cm At risk 12.5–13.4 cm Moderate malnutrition 11.5–12.4 cm Severe malnutrition <11.5 cm Developmental Milestones Social smile 1.5 months Head control 4 months Sits unsupported 7 months Crawls 10 months Stands unsupported 10–12 months Walks 12–13 months Talks 18 months CSF WBC (/mm³) Term newborn 0–25 >2 weeks 0–5
