- See:
- Growth of Proximal Tibial Epiphysis
- Avulsion of the Tibial Tubercle
- Discussion:
- injuries of prox tibial epiphysis are rare (3 % of lower extremity epiphyseal frx);
- injury is uncommon because knee ligaments bypass proximal tibial epiphysis and instead insert more distally;
- proximal tibial epiphysis is becomes separated from metaphysis, however, nutrient vessels are usually not damaged & therefore future growth is not disturbed;
- frequency of Salter Harris Injuries:
- SH type I: 15 %;
- SH type II: > 40 %;
- most common proximal tibial epiphyseal frx ( > 40%);
- injury occurs primarily in older children and adolescents;
- SH type III > 20 %;
- SH type IV > 15%
- SH type-V: 2 %
- Anatomy:
- attachment of tibial collateral ligament to metaphysis transmits stress to metaphysis rather than to epiphysis;
- w/ growth, proximal tibial physis fuses asymmetrically from posterior to anterior;
- Mechanism:
- hyperextension force that displaces tibial metaphysis posteriorly;
- flexion force may also cause a Salter-Harris type-II or III injury;
- w/ growth, proximal tibial physis fuses asymmetrically from posterior to anterior, & flexion force may cause fracture anteriorly where the physis is still open;
- Physical Findings:
- severe pain & swelling & limitation of extension & flexion of knee;
- beware of compartment syndrome;
- tenderness usually is present over proximal tibial physis distal to joint line, but soft-tissue swelling may make it difficult to localize tenderness.
- posterior displacement of proximal tibial metaphysis will produce visible & palpable concavity anteriorly at level of tibial tuberosity;
- Radiographs:
- non-displaced frx may not be visible on plain AP or lateral x-rays so consider oblique radiographs;
- frx lines may extend upward thru epiphysis or distally into metaphysis.
- small fleck of bone at periphery of metaphysis may be only finding;
- occasionally, CT scanning or MRI may be helpful.
- stress x-rays in coronal & sagittal planes may be helpful;
- if pt has sustained abduction injury, medial portion of physis will open w/ valgus stress;
- on lateral radiograph, posterior portion of physis may open w/ hyperextension stress.
- Non Operative Treatment
- most SH I & II frx can be treated w/ closed reduction & immobilization.
- Operative Treatment:
- Displaced Salter-Harris type-III and IV Frx;
- closed reduction & percutaneous pinning;
- two smooth K wires or small cannulated screws are inserted horizontally across epiphysis w/o crossing the physis;
- open reduction:
- indicated if anatomic reduction cannot be obtained;
- pes anserinus may be interposed in frx which may prevent reduction;
- Post Reduction Care:
- always beware of compartment syndrome;
- limb is immobilized in above-knee splint w/ knee in 10-20 deg of flexion;
- after several days, above-knee cast is applied & is worn until frx unites;
- fracture union usually occurs in six to eight weeks;
- Complications:
- angular deformity:
- most common complication (up to 30%);
- most common after SH type-IV frx;
- limb-Length Deformity:
- limb-length discrepancy occurred in 19 % (11) of 57 pts in two series, & both type-I & type-II fractures can cause growth arrest;
- neurovascular injuries:
- commonly occur because popliteal artery lies adjacent to tibial epiphysis & is tethered as anterior tibial artery crosses interosseous membrane & courses into anterior compartment;
- sagittal plane displacement can injure either the popliteal or anterior tibial artery.
- see popliteal artery injury follow knee dislocation;
- because of high risk of vascular injury w/ this frx, arteriogram is indicated if foot is cool & pale or if any abnormality in pulses is noted.
- vascular impairment may be subtle;
- references:
- Popliteal arterial thrombosis resulting from disruption of the upper tibial epiphysis.
Trauma involving the proximal tibial epiphysis.
Epiphyseal fractures of the proximal tibia.
Fractures of the tibia through the proximal tibial epiphyseal cartilage.