Injuries of the lower limb

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Injuries of the Lower Limb

A systematic overview covering fractures, dislocations, soft tissue injuries, and muscle injuries of the lower extremity, drawn from Rockwood and Green's Fractures in Adults (10th ed., 2025) and Gray's Anatomy for Students.

1. Proximal Femur Fractures

Femoral Neck Fractures

These are predominantly fragility fractures of the elderly (average age ~80 years, 64% female). The majority (80%) result from a simple fall from standing height.

Subtype	Prevalence	Average Age	M/F
Displaced	63%	81.1 yr	34/66
Minimally displaced	25%	78.5 yr	34/66
Basiocervical	12%	80.2 yr	42/58

Key complications:

1-year mortality in elderly: ~30%
15–20% cannot return to previous residence

Trochanteric (Intertrochanteric/Subtrochanteric) Fractures

Also predominantly fragility fractures (84% from standing falls, average age >81 years, 69–78% female).

Subtype	Prevalence	1-yr Mortality
Intertrochanteric	78%	~26%
Subtrochanteric	22%	~26%

The femoral head fracture is rare and strongly associated with hip dislocation (25% of hip dislocations have a concomitant femoral head fracture).

2. Femoral Diaphysis Fractures

Historically considered a "young person's fracture" from high-energy trauma (road traffic accidents), the epidemiology has shifted. Today the femoral diaphyseal fracture is a fragility fracture, increasingly seen in elderly patients, particularly elderly women. Periprosthetic fractures are now 17% of cases (average age 78 years). The annual overall incidence is approximately 14.3 per 100,000 population.

3. Distal Femur Fractures

Regarded as the classic fracture of elderly women — rare in young males, rising in incidence with age in both sexes, with a marked female predominance. 27.9% are periprosthetic (70% around knee prostheses).

Type	Prevalence	Avg Age	M/F
Extra-articular	38.6%	64.6 yr	33/67
Partial articular	17.6%	60.2 yr	55/45
Complete articular	6.4%	63.1 yr	45/55
Periprosthetic	27.9%	77.4 yr	18/82

1-year mortality is approximately 21%.

4. Patella Fractures

Relatively rare, with a bimodal distribution (type F curve). About two-thirds result from a standing fall in older patients; in younger males, motorcycle injuries account for two-thirds of cases. Transverse fractures are most common.

5. Proximal Tibia (Tibial Plateau) Fractures

Account for 2% of all fractures. Show a bimodal distribution (type H): high-energy injuries in younger males (>60% occur in men under 50), and fragility-type injuries in older women (>77% of women are over 50).

Type	Prevalence	Avg Age	M/F
Partial articular	64%	54 yr	38/62
Extra-articular	18%	56 yr	50/50
Complete articular	18%	53 yr	47/53

Key complications:

Compartment syndrome: 8.3%
Post-traumatic arthritis: 9–27%
Open fractures: 1.6%

6. Tibial Diaphysis Fractures

Now account for only ~1.1% of fractures treated by orthopaedic surgeons (declining incidence, likely reflecting improved road safety). The distribution remains type A (bimodal, but shifting). About 35% result from high-energy mechanisms.

7. Ankle Fractures

One of the most common lower limb fractures, accounting for 10.3% of all fractures. Annual incidence: 137–158 per 100,000 population (rising trend).

Classification (OTA/Weber):

Type	Prevalence	Avg Age	M/F
Transsyndesmotic (B)	63.6%	57 yr	38/62
Infrasyndesmotic (A)	24.3%	53 yr	36/64
Suprasyndesmotic (C)	12.1%	52 yr	52/48

65.7% are caused by a standing fall
Bimalleolar and trimalleolar fractures should be regarded as fragility fractures in the elderly
Open ankle fractures in elderly women carry mortality comparable to proximal femoral fractures

8. Calcaneal Fractures

The most common tarsal fracture. The dominant mechanism is a fall from a height (69%). Two main types:

Articular (type C): younger males, high-energy — more commonly bilateral, with associated lumbar spine fractures (8–17%) and contralateral calcaneal fracture (3–8%)
Non-articular: older patients

9. Midfoot & Metatarsal Fractures

Metatarsal fractures are common (6.6% of all fractures; incidence ~124/100,000). The 5th metatarsal is most frequently fractured. Bimodal distribution: young males and older females.
Midfoot (navicular, cuboid, cuneiform) fractures are rare; navicular is the most frequently injured midfoot bone (42% of midfoot fractures).

10. Dislocations

Hip Dislocations

Rare, typically high-energy (motor vehicle accidents, contact sport)
Annual incidence: 0.8 per 100,000 (adults)
96% are posterior dislocations
75% associated with fractures (acetabular rim, femoral head)
Prosthetic hip dislocations are far more common (22/100,000 in adults)

Knee Dislocations

Very rare (tibiofemoral): ~0.6/100,000; require high-energy trauma; associated with multiligament injury and vascular injury risk
Patellofemoral dislocations: much more common (21.6/100,000 overall); peak in adolescents and young adults, especially females aged 10–17; 22.7% risk of recurrence. Annual incidence in Finnish/Danish studies: 30–43/100,000.

Ankle & Foot Dislocations

Typically associated with high-energy trauma or fracture-dislocations
Isolated dislocations are rare

11. Soft Tissue (Ligamentous & Tendon) Injuries

Major lower limb soft tissue injuries by incidence (per 100,000/year):

Injury	Incidence	M/F	Avg Age
Meniscal tear	23.8	75/25	33–35 yr
Achilles tendon rupture	11.3	68/32	43–47 yr
Anterior cruciate ligament (ACL)	8.1	76/24	~28 yr
Medial collateral ligament (MCL)	5.2	75/25	31–39 yr
Posterior cruciate ligament (PCL)	—	male > female	younger
Lateral collateral ligament (LCL)	—	male > female	younger

ACL injuries: type C distribution (young adults). Swedish MRI-based studies report much higher incidence (~77/100,000), likely reflecting improved diagnostics.

12. Muscle Injuries

Muscle injuries result from direct trauma or overuse. They range from minor fiber tears (focal fluid on imaging) to complete muscle tears.

Hamstring Injuries

The most clinically important lower limb muscle injury. Common in athletes requiring power and speed (sprinting, football, track and field).

Mechanism: sudden acceleration/deceleration or rapid change of direction
Usual site: musculotendinous junction in adults
In adolescents: ischial apophysis avulsion (the apophysis is the weakest link in the proximal hamstring unit)
Diagnosed with ultrasound or MRI — MRI also gives prognostic information (re-tear risk, functional loss)

Coronal MRI of the Posterior Pelvis and Thigh Showing a Hamstring Avulsion Injury

Coronal MRI showing hamstring avulsion injury at the ischial tuberosity — Gray's Anatomy for Students

Soleus & Lower Leg Muscles

Below the knee, the soleus is the most common site of muscle tears, though other muscles of the posterior compartment may be affected.

Summary: Key Clinical Pearls

Injury	Typical Patient	Mechanism	Key Complication
Femoral neck fracture	Elderly woman	Low fall	30% 1-yr mortality, AVN
Intertrochanteric fracture	Elderly woman	Low fall	26% 1-yr mortality
Femoral shaft fracture	Historically young male; now also elderly	RTA / fragility	Fat embolism, blood loss
Distal femur fracture	Elderly woman / post-TKR	Low fall	Periprosthetic (28%)
Tibial plateau fracture	Young male / elderly female	High energy / low fall	Compartment syndrome (8.3%)
Ankle fracture	All ages	Twisting fall	Bimalleolar = fragility in elderly
Calcaneal fracture	Young to middle-aged male	Fall from height	Spinal fracture (8–17%)
ACL tear	Young adult	Sports	Meniscal injury, instability
Achilles rupture	Active middle-aged male	Eccentric load	Re-rupture
Hamstring avulsion	Adolescent athlete	Sudden hip flexion	Chronic pain, weakness

Sources: Rockwood and Green's Fractures in Adults, 10th ed. (2025), pp. 205–219 | Gray's Anatomy for Students, pp. 702–703

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