Posterior Tibial Avulsion | Posterior Approach | Screw or Suture Fixation
AVULSION TYPES
Critical Must-Knows
- PCL avulsion fracture = PCL avulses from posterior tibia with bone fragment (better prognosis than midsubstance tear)
- Posterior approach - patient prone, popliteal vessels at risk, must protect neurovascular bundle
- Optimal timing: Within 3 weeks - earlier fixation has better outcomes (85-95% good results)
- Fixation options: Screw (large fragment) or suture anchors (small fragment) - both achieve excellent outcomes
- Advantage over reconstruction: Bony healing is faster and more reliable than ligament reconstruction
Clinical Pearls
- "PCL avulsion fracture = PCL avulses from posterior tibia with bone fragment - better prognosis than midsubstance tear
- "Posterior approach with patient prone - popliteal artery at risk, must protect neurovascular bundle
- "Optimal timing within 3 weeks - earlier fixation achieves 85-95% good results
- "Screw fixation for large fragments, suture anchors for small fragments - both excellent outcomes
Critical PCL Avulsion Fracture Exam Points
Better Prognosis Than Midsubstance Tear
PCL avulsion fracture has better prognosis than midsubstance PCL tear. Bony healing is faster and more reliable than ligament reconstruction. 85-95% good results with proper fixation. Always attempt fixation if fragment is adequate.
Posterior Approach Critical
Posterior approach with patient prone - popliteal artery and tibial nerve at risk. Must protect neurovascular bundle. Use posterior midline or posteromedial approach. Identify vessels before any dissection.
Optimal Timing
Within 3 weeks for best outcomes - earlier fixation achieves 85-95% good results. Delayed fixation (over 6 weeks) may require reconstruction instead of fixation. Timing is critical for success.
Fixation Options
Screw fixation (large fragment) or suture anchors (small fragment) - both achieve excellent outcomes. Screw provides compression, suture anchors for small or comminuted fragments. Choose based on fragment size.
PCL Avulsion Fractures - Quick Decision Guide
| Fragment Size | Timing | Fixation Method | Outcome |
|---|---|---|---|
| Large (over 1cm) | Within 3 weeks | Screw fixation | 85-95% good results |
| Small (under 1cm) | Within 3 weeks | Suture anchors | 85-95% good results |
| Comminuted | Within 3 weeks | Suture anchors | 80-90% good results |
| Any size | Over 6 weeks | May need reconstruction | 60-80% good results |
PCL AVULSIONPCL Avulsion Fracture Features
| P | Posterior approach Patient prone, popliteal vessels at risk |
| C | Critical timing Within 3 weeks for best outcomes |
| L | Large fragment Screw fixation (over 1cm) |
| A | Anchors Suture anchors for small fragments |
| V | Vessels Popliteal artery and tibial nerve at risk |
| U | Under 3 weeks Optimal timing for fixation |
| L | Ligament Better prognosis than midsubstance tear |
| S | Screw or suture Both achieve excellent outcomes |
| I | Identify Identify neurovascular bundle first |
| O | Outcomes 85-95% good results with proper fixation |
| N | Non-weight bearing 6 weeks postoperatively |
| P | Posterior approach Patient prone, popliteal vessels at risk | A | Anchors Suture anchors for small fragments | L | Ligament Better prognosis than midsubstance tear | O | Outcomes 85-95% good results with proper fixation |
| C | Critical timing Within 3 weeks for best outcomes | V | Vessels Popliteal artery and tibial nerve at risk | S | Screw or suture Both achieve excellent outcomes | N | Non-weight bearing 6 weeks postoperatively |
| L | Large fragment Screw fixation (over 1cm) | U | Under 3 weeks Optimal timing for fixation | I | Identify Identify neurovascular bundle first |
Hook:PCL AVULSION: Posterior approach, Critical timing (3 weeks), Large fragment = screw, Anchors for small, Vessels at risk, Under 3 weeks optimal, Ligament better than midsubstance, Screw or suture both good, Identify vessels first, Outcomes 85-95%, Non-weight bearing 6 weeks!
POSTERIORPosterior Approach Steps
| P | Prone position Patient prone on operating table |
| O | Open approach Posterior midline or posteromedial |
| S | Safely identify Identify popliteal vessels and tibial nerve first |
| T | Tibial fragment Expose PCL avulsion fragment |
| E | Expose Expose posterior tibia and fragment |
| R | Reduce Reduce fragment to tibial bed |
| I | Internal fixation Screw or suture anchors |
| O | Outcomes 85-95% good results |
| R | Repair Repair PCL to bone |
| P | Prone position Patient prone on operating table | T | Tibial fragment Expose PCL avulsion fragment | I | Internal fixation Screw or suture anchors |
| O | Open approach Posterior midline or posteromedial | E | Expose Expose posterior tibia and fragment | O | Outcomes 85-95% good results |
| S | Safely identify Identify popliteal vessels and tibial nerve first | R | Reduce Reduce fragment to tibial bed | R | Repair Repair PCL to bone |
Hook:POSTERIOR approach: Prone position, Open approach, Safely identify vessels, Tibial fragment exposure, Expose posterior tibia, Reduce fragment, Internal fixation, Outcomes excellent, Repair PCL!
RISKSComplications
| R | Retraction injury Popliteal vessels during exposure |
| I | Inadequate fixation Fragment displacement, nonunion |
| S | Stiffness Arthrofibrosis (5-10%) |
| K | Killer curve Not applicable (avulsion, not reconstruction) |
| S | Stiffness Prolonged immobilization |
| R | Retraction injury Popliteal vessels during exposure | K | Killer curve Not applicable (avulsion, not reconstruction) |
| I | Inadequate fixation Fragment displacement, nonunion | S | Stiffness Prolonged immobilization |
| S | Stiffness Arthrofibrosis (5-10%) |
Hook:RISKS: Retraction injury to vessels, Inadequate fixation causes nonunion, Stiffness from immobilization, Killer curve not applicable (avulsion), Stiffness prevention with early ROM!
Overview and Epidemiology
PCL avulsion fractures occur when the PCL avulses from its insertion on the posterior tibia, taking a bone fragment with it. This is better than midsubstance PCL tears because bony healing is faster and more reliable than ligament reconstruction. Treatment involves surgical fixation via posterior approach.
Mechanism of Injury
Dashboard injury (classic mechanism):
- Motor vehicle accident: Knee strikes dashboard with knee flexed
- Posterior force: Posteriorly directed force on proximal tibia
- PCL avulses: PCL insertion on posterior tibia avulses with bone fragment
- High energy: Usually high-energy trauma
Other mechanisms:
- Hyperflexion: Extreme knee flexion
- Direct trauma: Posterior blow to proximal tibia
- Fall: Landing on flexed knee
The PCL inserts on the posterior tibia, 1-1.5cm below the joint line. When excessive posterior force is applied, the PCL avulses from the tibia, taking a bone fragment with it.
Better Prognosis Than Midsubstance Tear
PCL avulsion fracture has better prognosis than midsubstance PCL tear. Bony healing is faster and more reliable than ligament reconstruction. 85-95% good results with proper fixation vs 60-80% for midsubstance tears. Always attempt fixation if fragment is adequate.
Epidemiology
- Incidence: 5-10% of PCL injuries
- Age: Peak 20-40 years (trauma population)
- Gender: Male predominance (3:1 ratio)
- Laterality: Usually unilateral
- Associated injuries: PLC injury (20-30%), ACL injury (10-15%), meniscal tears (10-20%)
Anatomy and Pathophysiology
PCL Anatomy
The posterior cruciate ligament (PCL):
- Origin: Posteromedial lateral femoral condyle (intercondylar notch)
- Insertion: Posterior tibia, 1-1.5cm below joint line (posterior intercondylar area)
- Two bundles: Anterolateral (AL) and posteromedial (PM)
- Blood supply: Middle genicular artery
- Function: Primary restraint to posterior tibial translation (95% at 90 degrees flexion)
PCL insertion site:
- Location: Posterior tibia, 1-1.5cm below joint line
- Size: 1-2cm area
- Relationship: Close to popliteal artery (separated by popliteus muscle)
- Bone quality: Good cancellous bone for fixation
Pathophysiology
Avulsion mechanism:
- Posterior force: Excessive posterior force on proximal tibia
- PCL tension: PCL experiences excessive tension
- Bone weaker than ligament: In some cases, bone-ligament interface fails
- Avulsion: PCL avulses from tibia with bone fragment
Why avulsion is better:
- Bony healing: Faster and more reliable than ligament healing
- Anatomic: Can restore native PCL insertion
- Outcomes: 85-95% good results vs 60-80% for midsubstance tears
- Timing: Earlier fixation has better outcomes
Fragment characteristics:
- Size: Usually 1-2cm (varies)
- Location: Posterior tibia, PCL insertion site
- Quality: Usually good bone quality
- Displacement: Usually displaced posteriorly
Popliteal Artery at Risk
Popliteal artery lies directly posterior to the tibia, separated by only the popliteus muscle. During posterior approach, the neurovascular bundle must be carefully protected. Tethering at the soleal arch makes it vulnerable to injury with posterior displacement.
Classification Systems
Fragment Size Classification
Large fragment (over 1cm):
- Usually single fragment
- Good bone quality
- Treatment: Screw fixation (compression)
- Outcomes: 85-95% good results
Small fragment (under 1cm):
- May be single or multiple fragments
- Treatment: Suture anchors
- Outcomes: 85-95% good results
Comminuted:
- Multiple fragments
- May be difficult to fix
- Treatment: Suture anchors or reconstruction
- Outcomes: 80-90% good results
Fragment size determines fixation method and predicts outcomes.
Clinical Assessment
History
Mechanism: Dashboard injury (classic)
- Motor vehicle accident (knee strikes dashboard)
- Posterior force on proximal tibia
- High-energy trauma
Symptoms:
- Immediate pain and swelling
- Inability to bear weight
- Knee "giving way" (instability)
- Posterior knee pain
Physical Examination
Inspection:
- Knee effusion (hemarthrosis)
- Antalgic gait
- Knee held in slight flexion
Palpation:
- Tenderness over posterior knee
- Posterior tibial step-off (abnormal - normal is 1cm anterior)
Range of Motion:
- Limited flexion (pain, effusion)
- Limited extension (pain, effusion)
Ligament Testing:
- Posterior drawer: Positive (posterior translation) - most sensitive
- Posterior sag sign: Positive (tibia sags posteriorly)
- Quadriceps active test: Positive (tibia reduces with quadriceps contraction)
- Dial test: May be positive (if PLC injured)
Clinical Examination Key Point
Posterior drawer test is most sensitive for PCL injury - assess posterior tibial translation and endpoint quality. Normal tibial step-off is 1cm anterior to femoral condyle. PCL injury causes posterior translation.
Associated Injuries
- PLC injury: 20-30% (posterolateral corner)
- ACL injury: 10-15%
- Meniscal tears: 10-20%
- Bone bruises: Anterior tibia, anterior femur (kissing contusion pattern)
Differential Diagnosis
Distinguishing PCL Tibial Avulsion From Mimics
| Condition | Key Distinguishing Feature | Confirming Investigation |
|---|---|---|
| PCL tibial bony avulsion | Posterior drawer/sag with bony fragment at posterior tibial insertion | Lateral radiograph + CT (fragment, displacement) |
| Midsubstance PCL tear | Posterior sag/drawer but no bony fragment | MRI (discontinuous PCL fibres, no avulsed bone) |
| Posterolateral corner (PLC) injury | Increased external rotation (dial test) at 30 degrees, varus laxity | MRI; stress radiographs; examine before attributing all laxity to PCL |
| Tibial plateau / Segond-type fracture | Lateral capsular/anterolateral fragment, not posterior insertion | AP radiograph + CT |
| Knee dislocation (multiligament) | Gross instability, dimple sign, vascular compromise | Urgent ABI/CT angiography - exclude before elective fixation |
| Physeal injury (skeletally immature) | Tibial spine/physeal avulsion rather than PCL insertion | Radiograph + MRI to define physis |
Controversies & Areas of Uncertainty
Open vs Arthroscopic Fixation
The biggest live debate. A Level II RCT (Sundararajan 2020) and two systematic reviews (Hooper 2017, Song 2018) show equivalent functional outcomes. Arthroscopy avoids open popliteal dissection but is longer, costlier, and carried the only popliteal artery injury and both non-unions in the RCT. No clear winner - surgeon expertise and fragment morphology decide.
Implant Choice
Lag screw (large solid fragment), suture/suture-bridge or suture-button (small/comminuted), and staple have all shown good results. Biomechanically, suture fixation is equivalent to a screw at time zero (Sasaki 2007). No construct is proven superior in clinical trials.
Timing & Chronicity
Early anatomic fixation is widely advocated, but the precise window is not defined by high-level evidence. Chronic/malunited fragments may need takedown, bone grafting or reconstruction; the threshold for abandoning fixation in favour of reconstruction is opinion-based.
Truly Non-Displaced Fragments
Whether minimally/non-displaced bony avulsions can be managed non-operatively (brace in extension) versus prophylactic fixation is unresolved - reasonable conservative trials exist, but displacement and instability lower the threshold to operate.
Investigations
Standard X-ray Protocol
Views: AP and lateral knee.
Key findings:
- PCL avulsion fragment: Visible on lateral view (posterior tibia)
- Fragment size: Assess size and displacement
- Posterior tibial step-off: Abnormal (normal is 1cm anterior)
- Associated fractures: Tibial plateau, femoral condyle
Lateral view is critical - shows fragment and posterior displacement.
Management Algorithm
Management Pathway
PCL Avulsion Fracture Management
Determine fragment size, displacement, and timing. Assess for associated injuries (PLC, ACL, meniscus). Plan surgical approach.
Optimal timing. Posterior approach, reduce fragment, fix with screw (large) or suture anchors (small). Excellent outcomes (85-95% good results).
May still be fixable. Attempt fixation if fragment mobile. May need reconstruction if fixed. Good outcomes (75-85%).
Fragment usually fixed. May require PCL reconstruction instead of fixation. Outcomes lower (60-80%).
Surgical Technique
Posterior Approach Technique
Patient Positioning:
- Prone on standard operating table
- Tourniquet on thigh (may deflate for exposure)
- Contralateral leg abducted
- Image intensifier positioned
Incision:
- Posterior midline or posteromedial approach
- 8-10cm incision
- Full-thickness flaps
Exposure:
- Identify neurovascular bundle first (popliteal artery, tibial nerve)
- Protect with vessel loops
- Retract medially or laterally
- Expose posterior tibia
- Identify PCL avulsion fragment
Critical: Popliteal artery at risk - must identify and protect before any dissection.
Popliteal Artery Protection
Popliteal artery lies directly posterior to the tibia, separated by only the popliteus muscle. During posterior approach, identify and protect the neurovascular bundle before any dissection. Use vessel loops to retract. Avoid excessive retraction. The artery is vulnerable to injury with posterior displacement.
Complications
| Complication | Incidence | Risk Factors | Prevention/Management |
|---|---|---|---|
| Neurovascular injury | Less than 5% | Inadequate exposure, excessive retraction | Identify vessels first, protect with vessel loops |
| Nonunion | 5-10% | Inadequate fixation, poor reduction | Secure fixation, good bone apposition |
| Residual laxity | 10-15% | Malreduction, inadequate fixation | Anatomic reduction, secure fixation |
| Stiffness | 5-10% | Prolonged immobilization | Early ROM (2-4 weeks) |
| Hardware issues | 5-10% | Prominent hardware | Countersink screws, use suture anchors if prominent |
Neurovascular Injury
Less than 5% incidence:
- Cause: Inadequate exposure, excessive retraction, direct injury
- Prevention: Identify popliteal artery and tibial nerve first, protect with vessel loops, avoid excessive retraction
- Management: Immediate vascular surgery consultation if arterial injury
Nonunion
5-10% incidence:
- Cause: Inadequate fixation, poor reduction, fragment devascularization
- Prevention: Secure fixation, good bone apposition, proper timing
- Management: Revision fixation with bone graft if needed
Residual Laxity
10-15% incidence:
- Cause: Malreduction, inadequate fixation, fragment resorption
- Prevention: Anatomic reduction, secure fixation
- Management: Revision fixation if symptomatic, PCL reconstruction if needed
Postoperative Care
Immediate Postoperative
- Immobilization: Hinged knee brace locked in extension (4-6 weeks)
- Weight bearing: Non-weight bearing initially (4-6 weeks)
- ROM: Begin passive ROM at 2-4 weeks (unlock brace)
- PT: Quadriceps sets, straight leg raises (immediate)
Rehabilitation Protocol
Weeks 0-2:
- Brace locked in extension
- Non-weight bearing
- Quadriceps sets, straight leg raises
- Ice and elevation
Weeks 2-4:
- Unlock brace for passive ROM (0-90 degrees)
- Continue non-weight bearing
- Stationary bike (when ROM allows)
- Continue quadriceps strengthening
Weeks 4-6:
- Progressive weight bearing (partial to full)
- Full passive ROM
- Continue quadriceps strengthening
- Balance and proprioception
Weeks 6-12:
- Full weight bearing
- Progressive strengthening
- Sport-specific training
- Return to sport (when strength and ROM normal)
Return to Sport
Criteria:
- Full ROM (equal to contralateral)
- Quadriceps strength greater than 90% of contralateral
- No instability (negative posterior drawer)
- Functional testing passed
Timeline: Usually 6-9 months postoperatively.
Outcomes and Prognosis
Overall Outcomes
Surgical fixation outcomes:
- Success rate: 85-95% (excellent with proper technique and timing)
- Functional outcomes: 80-85% return to pre-injury level
- Complications: 10-15% (nonunion, residual laxity, stiffness)
Timing effects:
- Acute (under 3 weeks): 85-95% good results
- Subacute (3-6 weeks): 75-85% good results
- Chronic (over 6 weeks): 60-80% good results (may need reconstruction)
Functional Outcomes
Return to sport:
- Timeline: 6-9 months postoperatively
- Rate: 80-85% return to pre-injury level
- Factors: Age, sport level, rehabilitation compliance, timing of fixation
Functional testing:
- Quadriceps strength: 90%+ of contralateral
- No instability (negative posterior drawer)
- Full ROM
Long-Term Prognosis
Residual laxity:
- 10-15% have some residual posterior laxity
- Usually asymptomatic (does not affect function)
- May require revision if symptomatic
Arthritis risk:
- Low risk with proper treatment (less than 5% at 10 years)
- Higher risk with malreduction or persistent instability
- Proper reduction and fixation minimize risk
Factors Affecting Outcomes
Positive factors:
- Early fixation (within 3 weeks)
- Anatomic reduction
- Secure fixation
- Complete rehabilitation
Negative factors:
- Delayed fixation (over 6 weeks)
- Malreduction
- Inadequate fixation
- Incomplete rehabilitation
Prevention and Return to Sport
Prevention
Primary prevention:
- Proper seatbelt use (prevents dashboard injury)
- Airbag deployment
- Safe driving practices
- Protective equipment in sports
Secondary prevention (after injury):
- Complete rehabilitation before return to sport
- Continued strength and conditioning
- Gradual return to activity
Return to Sport Criteria
Clinical:
- Full ROM (equal to contralateral)
- Quadriceps strength greater than 90% of contralateral
- No effusion
- No instability (negative posterior drawer)
Functional:
- Single-leg hop test (greater than 90% of contralateral)
- Agility testing passed
- Sport-specific drills completed
Timeline: Usually 6-9 months postoperatively, depending on sport and level.
Evidence Base
Open vs Arthroscopic Fixation - Systematic Review (637 patients)
- MVA caused 68.4% of injuries (motorcycle 59% of those) - confirms dashboard/high-energy mechanism
- Open and arthroscopic fixation give comparable validated outcome scores
- Arthrofibrosis is the most common complication for both approaches
ARIF vs ORIF - Randomised Controlled Trial
- Functional outcomes equivalent between open screw and arthroscopic suture fixation
- ORIF was faster, cheaper and had fewer complications in this trial
- The single popliteal artery injury occurred during the arthroscopic technique
Open vs Arthroscopic - Pooled Systematic Review (308 patients)
- Both approaches achieve good clinical outcomes and radiological union
- Residual side-to-side laxity 0-5 mm in both groups
- No clear superiority of one fixation strategy over the other
All-Arthroscopic High-Strength Suture Fixation
- Arthroscopic suture fixation suitable for small or comminuted fragments not amenable to a screw
- Large Lysholm/IKDC gains with restoration of posterior stability (KT-3000 1.1 mm)
- Avoids open popliteal dissection and a second hardware-removal procedure
Open Screw vs Arthroscopic Suture - Cadaveric Biomechanics
- Arthroscopic suture fixation is biomechanically equivalent to open screw fixation at time zero
- No difference in posterior displacement or construct stiffness
- Provides rationale for suture techniques that avoid popliteal fossa exposure
Open Staple Fixation - Stress Radiograph Outcomes
- Staple fixation is a simple, reliable alternative for the bony avulsion fragment
- Stress radiography confirmed restoration of posterior stability vs contralateral knee
- All fractures united without implant migration
Exam Viva Scenarios
Use these scenarios to practise clinical reasoning and management decisions
Scenario 1: Acute PCL Avulsion Fracture
"A 30-year-old man presents to ED after a motor vehicle accident. He was the driver and his knee struck the dashboard. He has a swollen, painful knee and cannot bear weight. Examination shows positive posterior drawer test and posterior sag sign. X-ray shows a PCL avulsion fracture with a 1.5cm fragment displaced posteriorly."
Scenario 2: Comminuted PCL Avulsion
"A 35-year-old athlete presents 2 weeks after a high-energy knee injury. He has persistent instability and cannot return to sport. Examination shows positive posterior drawer and posterior sag. CT scan shows a comminuted PCL avulsion fracture with multiple small fragments (largest 8mm)."
Scenario 3: Open or Arthroscopic - Justify Your Choice
"An examiner shows you a lateral radiograph and a CT of a displaced single-fragment PCL tibial avulsion in a 28-year-old motorcyclist. MRI shows an associated lateral meniscal tear. The examiner asks: 'Would you fix this open or arthroscopically, and what does the evidence say?'"
MCQ Practice Points
Better Prognosis
Q: Why do PCL avulsion fractures have better prognosis than midsubstance PCL tears? A: Bony healing is faster and more reliable - PCL avulsion fractures achieve 85-95% good results with proper fixation vs 60-80% for midsubstance tears. Bony healing is more predictable than ligament reconstruction.
Optimal Timing
Q: What is the optimal timing for PCL avulsion fracture fixation? A: Within 3 weeks - Earlier fixation achieves 85-95% good results. Delayed fixation (over 6 weeks) has lower success rate (60-80%) and may require reconstruction instead of fixation.
Surgical Approach
Q: What is the surgical approach for PCL avulsion fracture fixation? A: Posterior approach with patient prone - Popliteal artery and tibial nerve at risk. Must identify and protect neurovascular bundle before any dissection. Use vessel loops to retract.
Fixation Method
Q: What fixation method is used for large PCL avulsion fragments (over 1cm)? A: Screw fixation - Provides compression across fracture. For small fragments (under 1cm) or comminuted, use suture anchors. Both achieve excellent outcomes (85-95% good results).
Neurovascular Risk
Q: What structure is at risk during posterior approach for PCL avulsion fracture? A: Popliteal artery - Lies directly posterior to the tibia, separated by only the popliteus muscle. Must identify and protect before any dissection. Injury risk is less than 5% with proper technique.
Outcomes
Q: What are the outcomes of PCL avulsion fracture fixation? A: 85-95% good results with proper technique and timing (within 3 weeks). Better than midsubstance PCL tears (60-80%). Bony healing is faster and more reliable than ligament reconstruction.
Guidelines, Registries & Global Practice
Global Epidemiology
- PCL injuries account for roughly 3-20% of acute knee ligament injuries; isolated bony tibial avulsions are a small subset.
- In pooled series, motor vehicle and motorcycle trauma cause the majority of tibial-sided avulsions (around 68% in the largest systematic review, with motorcycle crashes dominant in many Asian cohorts).
- High-energy mechanisms drive a male predominance and a 20-40 year peak. In limited-resource and high-motorcycle-density regions the absolute burden is higher.
Side-by-Side Guidance
How Different Bodies Frame PCL Avulsion Management
| Source | Position on Operative Fixation | Approach Emphasis |
|---|---|---|
| AAOS / AOSSM (US) | Surgical fixation for displaced bony avulsions; repair favoured over reconstruction when fragment adequate | Arthroscopic or open, surgeon-dependent |
| BOA / UK practice | Reduce and fix displaced fragments; protect neurovascular structures | Open posterior or arthroscopic in specialist centres |
| AO Foundation | Anatomic reduction and stable fixation (lag screw for large fragment) with early protected motion | Open posterior (Burks/Trickey) approach detailed |
| ESSKA / European | No single mandated technique; emphasis on stability and addressing concomitant injury | Arthroscopic suture-button techniques increasingly favoured |
There is no high-level guideline mandating a single technique. Consensus across societies is: displaced fragments should be reduced and stably fixed, repair is preferred over reconstruction when a fixable fragment exists, and concomitant ligament/meniscal injury must be addressed.
Registry & Resource Notes
- No dedicated arthroplasty-style registry tracks PCL avulsion fixation; evidence is limited to Level II RCTs and Level IV series/systematic reviews.
- High-resource settings: increasing use of arthroscopic suture-button/suture-bridge fixation to avoid open popliteal dissection, despite longer operative time and higher cost (Sundararajan RCT).
- Limited-resource settings: open posterior screw or staple fixation remains the workhorse - faster, cheaper, and not dependent on advanced arthroscopic instrumentation.
Orthopaedic Exam Relevance
A high-yield global viva topic. Be ready to discuss: bony avulsion is repairable (favour fixation over reconstruction), the dashboard/high-energy mechanism, prone open posterior versus arthroscopic fixation (equivalent functional outcomes - Hooper, Sundararajan, Song), the popliteal artery at risk, and screw-for-large versus suture-for-small/comminuted fragment selection. Arthrofibrosis is the commonest complication.
PCL AVULSION FRACTURES
Clinical summary
Key Anatomy
- •PCL insertion: Posterior tibia, 1-1.5cm below joint line
- •Popliteal artery: Directly posterior to tibia, separated by popliteus muscle
- •PCL function: Primary restraint to posterior tibial translation (95% at 90° flexion)
- •Two bundles: Anterolateral (AL) and posteromedial (PM)
Classification
- •By fragment size: Large (over 1cm) = screw, Small (under 1cm) = suture anchors
- •By displacement: Minimal (under 2mm), Moderate (2-5mm), Severe (over 5mm)
- •By timing: Acute (under 3 weeks), Subacute (3-6 weeks), Chronic (over 6 weeks)
- •Comminuted: Multiple fragments - use suture anchors (2-3), not screw fixation
Treatment Algorithm
- •Acute (under 3 weeks): Surgical fixation (screw or suture anchors) - 85-95% good results
- •Subacute (3-6 weeks): Attempt fixation if mobile - 75-85% good results
- •Chronic (over 6 weeks): May need reconstruction - 60-80% good results
- •Timing is critical - earlier fixation has better outcomes
Surgical Pearls
- •Posterior approach with patient prone
- •Identify popliteal artery and tibial nerve first (critical for safety)
- •Screw fixation for large fragments (compression), suture anchors for small
- •Optimal timing within 3 weeks for best outcomes
Complications
- •Neurovascular injury: Less than 5% (prevent by identifying vessels first)
- •Nonunion: 5-10% (prevent with secure fixation, good apposition)
- •Residual laxity: 10-15% (prevent with anatomic reduction)
- •Stiffness: 5-10% (prevent with early ROM at 2-4 weeks)