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Duke Orthopaedics
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Wheeless' Textbook of Orthopaedics

Proximal Tibiofibular Joint Injuries



- Discussion:
    - function of the PTFJ
    - accept 1/6 the axial load of the leg
    - resist torsional stresses originating from the ankle
    - resist tensile forces created with weight bearing
    - resists lateral bending forces
    - subluxation is common in preadolescent females and resolves with skeletal maturity
    - may be confused with a Lateral meniscus tear
    - anatomy:
           - synovial joint
                  - in 10% of the population, the proximal tibiofibular joint is contiguous with the knee joint
                  - product of embryogenesis
                  - anterior joint capsule significantly thicker than posterior
           - anterior joint capsule composed of three ligamentous bands
                  - bands pass obliquely upward and attach to the lateral tibial condyle
           - posterior tibiofibular ligament is composed of two broad, thick ligamentous bands
                  - bands pass obliquely from the fibular head to the posterior aspect of the tibial condyle
                  - reinforced by the popliteus tendon
           - additional Stabilizers
                  - LCL
                  - arcuate Ligament
                  - fabellofibular lig.
                  - popliteofibular lig.
                  - popliteus
                  - biceps femoris tendon (inserts on the styloid process and fibular head and helps prevent anterior movement of fibular head)
            - anatomic variation
                  - two general anatomic variants
                  - oblique
                        - several studies have identified a higher propensity for instability/dislocation with the oblique variant
                        - oblique variant defined as >20 degrees of inclination from horizontal plane
                        - variable surface area averaging 17mm2, which  predisposes to instability
                        - more constrained articulation which increases torsional loads and predisposes to instability
                  - horizontal
                        - horizontal variant
                        - less than 20 degrees of inclination
                        - fibular head is seated in a groove behind a prominent lateral tibial ridge which enhances stability
                        - planar, circular surface with on average 26mm2 of surface area
    - kinematics:
           - knee flexion
           - anterior shift of the proximal fibula in flexion
           - biceps relaxes in flexion
           - LCL relatively loose > 30 degrees of flexion
    - knee extension:
           - LCL and biceps femoris tighten and proximal fibula shifts posteriorly
    - mechanism of injury:
           - inherently stable joint
           - ligamentous support
           - protected position
           - added protection of the LCL in extension
           - injury occurs with knee in flexion, the ankle is internally rotated and plantar-flexed
           - isolated dislocations are typically seen in activities requiring aggressive twisting motions of the knee
                 - soccer
                 - parachuting
                 - horseback riding
                 - may also be seen in trauma cases with assoc:
                        - posterior hip dislocation;
                        - open tibiofibular fx
                        - ankle Fx
                        - twisting injury or direct blow (car bumper)
    - instability/dislocation patterns
           - subluxation
           - dislocation
           - anterolateral
           - posteromedial
           - superior
                 - typically preadolescent females
                 - may have generalized ligamentous laxity or CTD
           - exam findings
                 - lateral knee pain
                 - frequently bilateral
                 - may have locking/popping
                 - often present without Hx of trauma
                 - aggravated by direct pressure over the fibular head
    - dislocations:
           - patients c/o pain, swelling, and sometimes prominence of the fibular head
           - many are unable to bear weight secondary to pain
           - ankle motion exacerbates knee pain
           - transient peroneal nerve palsy especially with posteromedial and superior dislocations
           - anterolateral dislocation
                 - fall on a flexed knee with the foot inverted and plantarflexed
                 - flexion leads to LCL laxity, predisposing to lateral dislocation
                 - peroneal muscles, EHL and EDL pull the proximal fibula anteriorly
                 - most common pattern of proximal tibiofibular dislocation (>85%)
                 - lateral knee pain, swelling, and prominence of the fibular head
                 - ankle motion exacerbates knee pain
                 - may be unable to bear weight secondary to pain
           - posteromedial dislocation
                 - likely mechanism is direct trauma from car bumper of a horseback rider striking knee on gatepost
                 - often associated with a peroneal nerve injury
                 - about 10 percent of proximal TF dislocations
           - posteromedial dislocation
           - superior dislocation
                 - classically associated with a concomitant high-energy ankle injury and superior migration of the entire fibula
                 - interosseous membrane disrupted
                 - 2% of proximal tibiofibular dislocations
                 - physical examination
                        - important to evaluate and document Neuro exam
                        - knee and ankle exam
                        - including LCL
                        - prominent lateral mass
                        - extremely TTP, worsens with ankle dorsiflexion & eversion as well as knee extension
                        - biceps femoris tendon may appear as a tense cord
   - chronic subluxation:
           - best to examine c knee flexed at 90 degrees
           - translation assessed in ant/post and med/lat planes
           - radulescucent sign
                 - elicited in prone position
                 - one hand stabilizes the thigh and the leg is internally rotated in an attempt to produce anterior fibular subluxation
           - physical examination
                 - Helfet Sign
                 - patient bears full weight through the affected limb
                 - if the patient has PTF instability they will hook the contralateral limb about the affected calf in an attempt to stabilize the PTF joint
            - imaging
                 - plain radiographs in true AP and lateral planes (72% sensitive)
                 - comparison radiographs of the contralateral extremity (increases sensitivity to 82%)
                 - resnick’s line – follows the lateral tibial spine and should be found over the midpoint of the fibular head
                 - CT if dx is equivocal (86% sens compared c 82% on plain films)
   - treatment: atraumatic subluxation
            - non-surgical mgmt is usually successful
            - casting for 2-3 weeks
            - strap applied 1cm below fibular head
            - avoid activities that place knee in hyperflexion
            - usually in preadolescent females and Symptoms are self-limiting
   - treatment of acute dislocation:
            - closed reduction
                  - may be performed under local or general anesthesia
                  - knee in  80-110 degrees of flexion
                  - ankle dorsiflexed and externally rotated
                  - reverse the injury
                  - audible pop as head relocates
                  - reassess knee stability/LCL once relocated
            - immobilization?
                  - controversial
                  - some authors advocate casting for 3 weeks vs. soft dressing with protected WB advanced to full WB over 6 weeks
            - open reduction
                  - for failed closed reduction
                  - for posteromedial and superior dislocations
                  - closed reduction may fail if the fibula is perched on the lateral tibial ridge with an intact LCL
                  - following open reduction the joint should be stabilized with
                  - temporary screw
                  - K wire
                  - associated ligamentous injuries should be repaired
            - treatment of acute dislocation:
                  - after ORIF the knee and ankle should be immobilized for 6 weeks
                  - K-wires or screws can be removed after 6-12 weeks
                  - recurrent symptoms
                        - Ogden, et al. reported that 57% (N=33) of pts c acute dislocations required surgery for recurrent symptoms
                  - surgical options
                        - arthrodesis
                              - isolate/protect the peroneal nerve
                              - denude articular surfaces of cartilage
                              - joint reduction and fixation with a cancellous lag screw
                              - immobilization for 6 weeks
                              - full weight bearing in 8 weeks
                              - prevents fibular rotation
                                    - concern regarding increased rotational stress at ankle joint
                                    - ? may lead to pain and arthritic changes of the ankle joint
                                    - insufficient data to support/refute this theory
                        - resection of fibular head
                              - particularly appealing in the face of Peroneal nerve palsy in pts with chronic subluxation/dislocation
                              - LCL and biceps secured to the tibia
                              - similar concerns as PTF arthrodesis as well as concern of knee instability with compromise of PLC
                              - N = 6 (tumor or autograft), avg 61 months F/U
                              - ? Effect of unilateral marginal resection of the proximal fibula on knee stability and gait.
                        - reconstruction of the PTFJ
                              - using one half of the biceps femoris tendon and a strip of deep fascia the PTFJ is reconstructed
                              - knee immobilized for 6 weeks and then PWB
                              - Giachino, et al (1986) reported return to previous activity level s recurrent symptoms in 2 patients
                              - 20 x 2cm strip of ITB still attached to Gerdy’s tubercle can  be passed from anterior to posterior through a drill hole in the tibia and underneath the LCL
                               - Fractures of the tibial tuberosity in adolescents
                               - Recurrent dislocations of the proximal tibiofibular joint. Report of two cases.



Proximal tibiofibular joint ganglion cysts: excision, recurrence, and joint arthrodesis.



Original Text by Clifford R. Wheeless, III, MD.

Last updated by Data Trace Staff on Friday, August 31, 2012 1:23 pm