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Fractures around the Knee
LOWER LIMB TRAUMA
thigh muscles. The quadriceps cause shortening, and the adductors produce varus deformity, while the gastrocnemius gives rise to posterior angulation. Classifications distinguish between extra- and intra-articular fractures. Articular fractures are partial (one condyle involved) or complete (both T- and Y-shaped fractures). The AO system is the most comprehensive (Figure 1). CT may be used to detect articular fragments. Open fractures constitute 5–10% of all supracondylar fractures. Vascular injury occurs in 2–3%, usually with damage to the superficial femoral artery at the adductor hiatus.
Fractures around the Knee Murtaza Adeeb Christopher G Moran
Fractures around the knee account for about 6% of all trauma admissions. They are broadly divided into three groups, namely supracondylar fractures of the femur, tibial plateau fractures and fractures of the patella. The age distribution is bimodal: high-energy fractures are seen in young men involved in road accidents and sports; the other high-risk group is elderly women with osteoporosis who suffer simple falls. This contribution should be read in conjunction with McGrath/Royston, page 231.
Management The aims of management are to obtain union in an anatomical position whilst allowing early motion. Closed treatment is indicated for patients with undisplaced/ incomplete fractures and patients unfit for surgery. It is very demanding and involves skeletal traction using proximal tibial and distal femoral pins with early cast bracing. Operative management is indicated for: • displaced fractures • patients with multiple injuries • open fractures • associated vascular or ligament injury requiring repair • irreducible fractures • pathological fractures. Good preoperative planning is essential. Various implants are available and the choice is determined by fracture configuration and the preference of the surgeon. The 95° condylar blade plate is a one-piece implant. It affords good control of the fracture, but is technically difficult to insert because the surgeon has to consider alignment in three planes simultaneously. The dynamic condylar screw applies interfragmentary compression across the femoral condyles. The condylar buttress plate is a broad dynamic compression plate with a clover leaf-shaped distal portion designed for the lateral distal femur. It is used for complex coronal fractures. Supracondylar nail is a retrograde intramedullary device inserted in the intercondylar notch just anterior to the femoral attachment of the posterior cruciate ligament. It can stabilize osteoporotic bone fractures and may be particularly helpful in the elderly. Locking plates are a recent development. These plates have threaded screw heads that allow the screws to lock into the plate, producing a fixed-angle device. The Less Invasive Stabilization System (LISS) plate is an example. This implant allows minimal access surgery and gives an excellent hold in osteoporotic bone. The external fixator is used as a temporary device, to span the knee, for initial management of severe open fractures. Advantages include rapid application, minimal soft tissue dissection and the ability to maintain length and wound access.
Initial management Initial management must always follow Advanced Trauma Life Support® (ATLS®) principles. Examination of an injured limb should include an assessment for: • open wounds • deformity • swelling • joint effusion • local tenderness • distal neurovascular status. Adequate analgesia should be given, the limb splinted, neurovascular status re-examined and radiographs obtained. Open fractures are a surgical emergency. After initial assessment: • the wound should be photographed to avoid repeated examination • the wound covered with saline or betadine swabs • broad-spectrum intravenous antibiotics administered • tetanus status established. Surgical debridement of the wound and skeletal stabilization should be performed within 6 hours.
Supracondylar fractures The supracondylar area is the distal 9 cm of the femur. The usual mechanism of injury is axial loading with varus, valgus or rotational forces. Deformities are produced primarily by the direction of initial fracture displacement and secondarily by the pull of
Murtaza Adeeb is a Clinical Fellow in Trauma and Orthopaedic Surgery at University Hospital, Nottingham, UK.
Supervised rehabilitation is essential. Patients should not bear weight on the joint for 8–12 weeks. The knee must be mobilized early and a functional range of movement (full extension to 110° of flexion) should be obtained.
Christopher G Moran is Special Professor in Trauma and Orthopaedic Surgery at University Hospital, Nottingham, UK.
SURGERY
228
© 2003 The Medicine Publishing Company Ltd
LOWER LIMB TRAUMA
��������������������������������������������������������� �� Simple
�� Metaphyseal wedge
�� Metaphyseal complex
�� Lateral condyle sagittal
�� Medial condyle sagittal
�� Posterior condyle coronal
�� Metaphyseal simple
�� Metaphyseal complex
�� Metaphyseal and articular complex
Articular simple
Articular simple
������ Metaphyseal fracture
������ Partial articular fracture
������ Complete articular fracture
Fractures of the distal femur are divided into three types, which are subdivided into three groups. These groups can be further subdivided into three subgroups (not shown), depending on the configuration of the fracture 1
Complications include infection (3%) particularly in high-energy open fractures. It should be aggressively managed by debridement and intravenous antibiotics. The implant should be retained until fracture union unless it is loose. Late complications include: • non-union (4%) • malunion with varus deformity and osteoarthritis of the patellofemoral joint (20%) • tibiofemoral joint (5%).
Clinical examination must include careful assessment for compartment syndrome and neurovascular status. Radiographs should include anteroposterior, lateral and 45° oblique views to assess displacement and joint congruity. CT provides useful information on the fracture in 75% of cases; ligament and meniscal injuries can be evaluated using MRI. Management The aims of management are to obtain union in an anatomical position whilst allowing early motion.
Outcome following these fractures is largely dictated by the extent of the initial injury. Good results have been reported in 70–85% of patients. Knee stiffness is a common problem.
Non-operative management can be used for undisplaced fractures and those with less than 10° valgus instability in full extension. The leg is placed into a hinged brace, allowing 0–90° of motion and the patient is mobilized, non-weight-bearing for 8 weeks.
Tibial plateau fractures Tibial plateau fractures involve the tibial articular surface of the knee. The mechanism of injury is strong valgus or varus force combined with axial loading resulting in the femoral condyle being forced against the tibial plateau. Most of the injuries affect the lateral plateau (60%) or both plateaus (30%). Isolated fracture of the medial plateau is less common (10%), but is a serious injury as it occurs in fracture dislocations of the knee and is associated with severe ligament and vascular injuries. These fractures are classified by the Schatzker classification (Figure 2). Types I–III are fractures of the lateral plateau, type IV is fracture of the medial plateau and types V and VI are bicondylar plateau fractures.
SURGERY
Surgery is indicated for many displaced fractures (Figure 3). Most fractures are treated by open reduction and internal fixation. The menisci must be preserved and ruptured ligaments repaired if possible. Bone graft is often required to fill defects below the articular surface and a buttress plate is used to provide fixation. Fractures with severe soft tissue injury may be treated with external fixation and circular frames (Ilizarov) can produce good results. Some simple fractures can be treated by arthroscopy-assisted minimal access surgery.
229
© 2003 The Medicine Publishing Company Ltd
LOWER LIMB TRAUMA
Treatment for tibial plateau fracture
����������������������������������������������������
Non-operative management • Undisplaced fracture • Medical co-morbidities • Advanced osteopenia • Selected spinal cord injuries
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Type I Split
Type II Split–depression
��������������
Surgery Lateral condyle fracture • Lateral tilt (valgus) >10° • Articular step >4 mm • Articular gap >5 mm
Type III Depression
�������������
Medial condyle • All except non-displaced fissures
Type IV
Type V
Bicondylar fractures • Any medial tilt (varus) • Lateral tilt (valgus) >10° • Axial: all displaced
Type VI
2
3
Rehabilitation must begin early, with active knee movements within 2 weeks. Patients should remain non-weight-bearing until fracture union (8–12 weeks).
Clinical examination should seek a palpable gap and bony tenderness, and assess the extensor mechanism with an active straight leg raise. Radiographs should include anteroposterior and lateral views of the knee in extension to show displacement of the fragments and step off of the articular surface. Skyline views can reveal marginal fractures. Bipartite patella (a normal variant) occurs when a secondary centre of ossification produces a second fragment at the superolateral corner. It may be mistaken for a fracture, but can be differentiated by site, rounded edges and lack of tenderness.
Complications are more common with high-energy fractures. Early local complications include infection (3–5%), wound necrosis and peroneal nerve palsy. Late complications include fixation failure. Non-union is rare, but malunion is common. Post-traumatic arthritis is rare in undisplaced fractures, but common in displaced lateral fractures (15%), medial fractures (20%) and bicondylar fractures (40%). Varus deformity and instability are important predisposing factors for arthritis.
Management The aim is to restore congruity of the patellofemoral joint and continuity of the extensor mechanism.
Outcome depends largely on the type of fracture sustained, its initial displacement and associated soft tissue injuries. Non-operative management of undisplaced fractures produces good-to-excellent long-term results in about 90% of patients. Similar results are seen in 65–75% of patients when open reduction and internal fixation are used to treat displaced unstable fractures. Knee stiffness remains the most common problem.
Closed treatment is indicated for undisplaced fractures with intact straight leg raise. This involves 6 weeks in an extension splint or cylinder cast, during which the patient may bear weight . Surgery is indicated for patients who are unable to perform straight leg raise. Open reduction and internal fixation using a tension band wire is the treatment of choice. In multifragmentary fractures, partial patellectomy with extensor tendon repair may be indicated. Total patellectomy may be necessary for the shattered patella, but has a poor outcome.
Patella fractures The patella is the largest sesamoid bone in the body. It is subcuticular and functions as a fulcrum to improve leverage of the quadriceps muscle and increase the extensor power. The mechanism of injury is either direct or indirect. A direct blow (e.g. a car dashboard injury, simple fall) causes incomplete, stellate or comminuted fractures, and is associated with other injuries (e.g. posterior dislocation of the hip, femoral shaft fractures). Patellar fractures from indirect forces occur when the intrinsic strength of the patella is exceeded by pull of the attached musculotendinous and ligamentous units and result in transverse fractures (50–80% of patellar fractures). SURGERY
Rehabilitation commences within a few days of surgery with active knee movements. Patients should not bear weight for 6 weeks and require physiotherapy to increase quadriceps strength. Complications include wound infection, residual weakness when climbing stairs and walking downhill and difficulty in kneeling. Outcome is generally good, and 70–80% of patients return to full function by 1 year. u 230
© 2003 The Medicine Publishing Company Ltd
thigh muscles. The quadriceps cause shortening, and the adductors produce varus deformity, while the gastrocnemius gives rise to posterior angulation. Classifications distinguish between extra- and intra-articular fractures. Articular fractures are partial (one condyle involved) or complete (both T- and Y-shaped fractures). The AO system is the most comprehensive (Figure 1). CT may be used to detect articular fragments. Open fractures constitute 5–10% of all supracondylar fractures. Vascular injury occurs in 2–3%, usually with damage to the superficial femoral artery at the adductor hiatus.
Fractures around the Knee Murtaza Adeeb Christopher G Moran
Fractures around the knee account for about 6% of all trauma admissions. They are broadly divided into three groups, namely supracondylar fractures of the femur, tibial plateau fractures and fractures of the patella. The age distribution is bimodal: high-energy fractures are seen in young men involved in road accidents and sports; the other high-risk group is elderly women with osteoporosis who suffer simple falls. This contribution should be read in conjunction with McGrath/Royston, page 231.
Management The aims of management are to obtain union in an anatomical position whilst allowing early motion. Closed treatment is indicated for patients with undisplaced/ incomplete fractures and patients unfit for surgery. It is very demanding and involves skeletal traction using proximal tibial and distal femoral pins with early cast bracing. Operative management is indicated for: • displaced fractures • patients with multiple injuries • open fractures • associated vascular or ligament injury requiring repair • irreducible fractures • pathological fractures. Good preoperative planning is essential. Various implants are available and the choice is determined by fracture configuration and the preference of the surgeon. The 95° condylar blade plate is a one-piece implant. It affords good control of the fracture, but is technically difficult to insert because the surgeon has to consider alignment in three planes simultaneously. The dynamic condylar screw applies interfragmentary compression across the femoral condyles. The condylar buttress plate is a broad dynamic compression plate with a clover leaf-shaped distal portion designed for the lateral distal femur. It is used for complex coronal fractures. Supracondylar nail is a retrograde intramedullary device inserted in the intercondylar notch just anterior to the femoral attachment of the posterior cruciate ligament. It can stabilize osteoporotic bone fractures and may be particularly helpful in the elderly. Locking plates are a recent development. These plates have threaded screw heads that allow the screws to lock into the plate, producing a fixed-angle device. The Less Invasive Stabilization System (LISS) plate is an example. This implant allows minimal access surgery and gives an excellent hold in osteoporotic bone. The external fixator is used as a temporary device, to span the knee, for initial management of severe open fractures. Advantages include rapid application, minimal soft tissue dissection and the ability to maintain length and wound access.
Initial management Initial management must always follow Advanced Trauma Life Support® (ATLS®) principles. Examination of an injured limb should include an assessment for: • open wounds • deformity • swelling • joint effusion • local tenderness • distal neurovascular status. Adequate analgesia should be given, the limb splinted, neurovascular status re-examined and radiographs obtained. Open fractures are a surgical emergency. After initial assessment: • the wound should be photographed to avoid repeated examination • the wound covered with saline or betadine swabs • broad-spectrum intravenous antibiotics administered • tetanus status established. Surgical debridement of the wound and skeletal stabilization should be performed within 6 hours.
Supracondylar fractures The supracondylar area is the distal 9 cm of the femur. The usual mechanism of injury is axial loading with varus, valgus or rotational forces. Deformities are produced primarily by the direction of initial fracture displacement and secondarily by the pull of
Murtaza Adeeb is a Clinical Fellow in Trauma and Orthopaedic Surgery at University Hospital, Nottingham, UK.
Supervised rehabilitation is essential. Patients should not bear weight on the joint for 8–12 weeks. The knee must be mobilized early and a functional range of movement (full extension to 110° of flexion) should be obtained.
Christopher G Moran is Special Professor in Trauma and Orthopaedic Surgery at University Hospital, Nottingham, UK.
SURGERY
228
© 2003 The Medicine Publishing Company Ltd
LOWER LIMB TRAUMA
��������������������������������������������������������� �� Simple
�� Metaphyseal wedge
�� Metaphyseal complex
�� Lateral condyle sagittal
�� Medial condyle sagittal
�� Posterior condyle coronal
�� Metaphyseal simple
�� Metaphyseal complex
�� Metaphyseal and articular complex
Articular simple
Articular simple
������ Metaphyseal fracture
������ Partial articular fracture
������ Complete articular fracture
Fractures of the distal femur are divided into three types, which are subdivided into three groups. These groups can be further subdivided into three subgroups (not shown), depending on the configuration of the fracture 1
Complications include infection (3%) particularly in high-energy open fractures. It should be aggressively managed by debridement and intravenous antibiotics. The implant should be retained until fracture union unless it is loose. Late complications include: • non-union (4%) • malunion with varus deformity and osteoarthritis of the patellofemoral joint (20%) • tibiofemoral joint (5%).
Clinical examination must include careful assessment for compartment syndrome and neurovascular status. Radiographs should include anteroposterior, lateral and 45° oblique views to assess displacement and joint congruity. CT provides useful information on the fracture in 75% of cases; ligament and meniscal injuries can be evaluated using MRI. Management The aims of management are to obtain union in an anatomical position whilst allowing early motion.
Outcome following these fractures is largely dictated by the extent of the initial injury. Good results have been reported in 70–85% of patients. Knee stiffness is a common problem.
Non-operative management can be used for undisplaced fractures and those with less than 10° valgus instability in full extension. The leg is placed into a hinged brace, allowing 0–90° of motion and the patient is mobilized, non-weight-bearing for 8 weeks.
Tibial plateau fractures Tibial plateau fractures involve the tibial articular surface of the knee. The mechanism of injury is strong valgus or varus force combined with axial loading resulting in the femoral condyle being forced against the tibial plateau. Most of the injuries affect the lateral plateau (60%) or both plateaus (30%). Isolated fracture of the medial plateau is less common (10%), but is a serious injury as it occurs in fracture dislocations of the knee and is associated with severe ligament and vascular injuries. These fractures are classified by the Schatzker classification (Figure 2). Types I–III are fractures of the lateral plateau, type IV is fracture of the medial plateau and types V and VI are bicondylar plateau fractures.
SURGERY
Surgery is indicated for many displaced fractures (Figure 3). Most fractures are treated by open reduction and internal fixation. The menisci must be preserved and ruptured ligaments repaired if possible. Bone graft is often required to fill defects below the articular surface and a buttress plate is used to provide fixation. Fractures with severe soft tissue injury may be treated with external fixation and circular frames (Ilizarov) can produce good results. Some simple fractures can be treated by arthroscopy-assisted minimal access surgery.
229
© 2003 The Medicine Publishing Company Ltd
LOWER LIMB TRAUMA
Treatment for tibial plateau fracture
����������������������������������������������������
Non-operative management • Undisplaced fracture • Medical co-morbidities • Advanced osteopenia • Selected spinal cord injuries
���������������
Type I Split
Type II Split–depression
��������������
Surgery Lateral condyle fracture • Lateral tilt (valgus) >10° • Articular step >4 mm • Articular gap >5 mm
Type III Depression
�������������
Medial condyle • All except non-displaced fissures
Type IV
Type V
Bicondylar fractures • Any medial tilt (varus) • Lateral tilt (valgus) >10° • Axial: all displaced
Type VI
2
3
Rehabilitation must begin early, with active knee movements within 2 weeks. Patients should remain non-weight-bearing until fracture union (8–12 weeks).
Clinical examination should seek a palpable gap and bony tenderness, and assess the extensor mechanism with an active straight leg raise. Radiographs should include anteroposterior and lateral views of the knee in extension to show displacement of the fragments and step off of the articular surface. Skyline views can reveal marginal fractures. Bipartite patella (a normal variant) occurs when a secondary centre of ossification produces a second fragment at the superolateral corner. It may be mistaken for a fracture, but can be differentiated by site, rounded edges and lack of tenderness.
Complications are more common with high-energy fractures. Early local complications include infection (3–5%), wound necrosis and peroneal nerve palsy. Late complications include fixation failure. Non-union is rare, but malunion is common. Post-traumatic arthritis is rare in undisplaced fractures, but common in displaced lateral fractures (15%), medial fractures (20%) and bicondylar fractures (40%). Varus deformity and instability are important predisposing factors for arthritis.
Management The aim is to restore congruity of the patellofemoral joint and continuity of the extensor mechanism.
Outcome depends largely on the type of fracture sustained, its initial displacement and associated soft tissue injuries. Non-operative management of undisplaced fractures produces good-to-excellent long-term results in about 90% of patients. Similar results are seen in 65–75% of patients when open reduction and internal fixation are used to treat displaced unstable fractures. Knee stiffness remains the most common problem.
Closed treatment is indicated for undisplaced fractures with intact straight leg raise. This involves 6 weeks in an extension splint or cylinder cast, during which the patient may bear weight . Surgery is indicated for patients who are unable to perform straight leg raise. Open reduction and internal fixation using a tension band wire is the treatment of choice. In multifragmentary fractures, partial patellectomy with extensor tendon repair may be indicated. Total patellectomy may be necessary for the shattered patella, but has a poor outcome.
Patella fractures The patella is the largest sesamoid bone in the body. It is subcuticular and functions as a fulcrum to improve leverage of the quadriceps muscle and increase the extensor power. The mechanism of injury is either direct or indirect. A direct blow (e.g. a car dashboard injury, simple fall) causes incomplete, stellate or comminuted fractures, and is associated with other injuries (e.g. posterior dislocation of the hip, femoral shaft fractures). Patellar fractures from indirect forces occur when the intrinsic strength of the patella is exceeded by pull of the attached musculotendinous and ligamentous units and result in transverse fractures (50–80% of patellar fractures). SURGERY
Rehabilitation commences within a few days of surgery with active knee movements. Patients should not bear weight for 6 weeks and require physiotherapy to increase quadriceps strength. Complications include wound infection, residual weakness when climbing stairs and walking downhill and difficulty in kneeling. Outcome is generally good, and 70–80% of patients return to full function by 1 year. u 230
© 2003 The Medicine Publishing Company Ltd