Subtalar Dislocations

1. Subtalar Dislocations Jennifer Gerres DPM, PGY-3

2. Objectives To discuss… The Mechanism of Injury Types of Subtalar Dislocations Therapeutic Approach Prognosis

3. Introduction Simultaneous dislocation Talocalcaneal and talonavicular joints Four types described Uncommon injury = 1 -2% of dislocations Most published series = small number of patients Occur in the 3 rd decade of life Men > women (6-10x more) 55% of medial and 72% of lateral dislocations have associated injury 30 % are irreducible by closed means

4. Mechanisms of Injury High energy MVA, falls from a height 68% of all dislocations with trend toward open Sports injury “basketball foot” Low energy Tripping over a step 10% in the literature = heavy selection bias? Grantham SA. J Trauma . 1964.

5. Anatomy Talus free of muscular insertions and origins Tendons encircle it Ligamentous stability Interosseous ligament = majority Deep deltoid and calcaneofibular ligaments

6. Types of Dislocation Medial, Lateral, Posterior, and Anterior Direction of the foot in relation to the talus

7. Medial Dislocation Most common = 80% Inversion/rotation Sustentaculum tali acts as a fulcrum Calcaneus displaced medially “Acquired clubfoot deformity” Barg A, et al. Foot Ankle Int . 2012 http:// eorif.com / AnkleFoot /subtalar%20dis%20C1.html

8. Medial Dislocation Rupture dorsal talonavicular ligament Talus externally rotates TNJ dislocation Sinus tarsi widens Interosseous ligament ruptures Talocalcaneal joint ruptures anterior to posterior Heck BE, et al . Foot Ankle Int . 1996.

9. Lateral Dislocation 17% of all dislocations High energy/eversion Anterior calcaneal process acts as a fulcrum Foot appears pronated/abducted “Acquired flatfoot” Toes plantarflexed De Palma L, et al. Arch Orthop Trauma Surg . 2008. Bibbo C, et al. Foot Ankle Int . 2003.

10. Lateral Dislocation Rupture anterior bundles of deltoid ligament Interosseous ligament ruptures STJ dislocation Dorsal talonavicular ligament ruptures Talus externally rotates TNJ dislocation Waldrop J, et al. Foot Ank l e . 1992.

11. Posterior Dislocation 2% of all dislocations Plantar hyper-flexion Tearing of the interosseous ligament Sliding of talar head over navicular Very high instability Convert to medial dislocation Jungbluth P, et al. J Bone Joint Surg Am . 2010

12. Anterior Dislocation < 1% of dislocations Traction force/excessive dorsiflexion Tearing interosseous ligament Sliding posterior facet beyond calcaneal tuber Very high instability Convert to lateral dislocation

13. Approach Physical Exam, Ancillary Studies, Treatment

14. Physical Exam Risk of skin necrosis Medial dislocation Lateral malleolus and dorsolateral talar head Lateral dislocation M edial malleolus and prominent medial talar head Open dislocation = 20 – 40% Bibbo C, et al. Foot Ankle Int . 2003: 88% had concomitant injuries to the foot and ankle Bryant J, Levis JT. West J Emerg Med . 2009.

15. Radiographs AP view is most helpful Talar head and navicular Congruent Lateral view Medial dislocation Talar head superior to navicular Lateral dislocation Talar head inferiorly displaced De Palma L, et al. Arch Orthop Trauma Surg . 2008 . Pesce D, et al. J Emerg Med . 2011.

16. CT Scan Bibbo C, et al. Foot Ankle Int . 2001: 9 cases in a 3 year period Plain films diagnosed subtalar joint dislocation in all cases 5 associated injuries observed CT identified additional injuries missed = 100% Total of 13 new findings 44% of cases, new information changed treatment Subtalar fusion (n=3), tarsal tunnel release, excision of bone fragments Bohay DR and Manoli A 2 nd . Foot Ankle Int . 1996: Occult intra-articular fractures identified on CT of 4 patients “…invaluable tool to assess for associated injuries in STJ dislocation, and should be performed in all cases of STJ dislocation.” Bibbo C, et al. Foot Ankle Int . 2001

17. Treatment Immediate closed reduction under sedation Prevent additional soft tissue damage Minimize neurovascular complications How To: Knee bent to relax gastrocnemius Traction applied at heel Counter-traction to thigh Deformity accentuated Medial dislocations = invert Lateral dislocations = evert Reverse with direct pressure over talar head and foot in plantar flexion

18. Treatment Bulky splint Medial dislocations = eversion Lateral dislocations = inversion Non- weightbearing 4 to 6 weeks Physical therapy program Strengthening and ROM Splint photo: Hsu RY, et al. Orthopedics . 2013.

19. Obstacles to Reduction Medial Dislocation “Buttonholing” of the talar head through: E xtensor digitorum brevis Extensor retinaculum Talonavicular ligaments Heck BE, et al. Foot Ankle Int . 1996: Cadaveric study did not demonstrate entrapment of EDB Entrapment of deep peroneal nerve Heck BE, et al . Foot Ankle Int . 1996 . Wagner R, et al. Injury . 2004

20. Obstacles to Reduction Lateral Dislocation Posterior tibial tendon Osteochondral fx fragments TNJ or STJ M ay act as bony block Waldrop J, et al. Foot Ank l e . 1992.

21. Open Treatment Medial Dislocation Longitudinal anteromedial incision over talar head/ neck Lateral Dislocation Longitudinal medial incision over talar head Allows access to posterior tibial tendon Disimpaction of talus and navicular Small, loose fragments removed Larger fragments fixed with k-wires or screws Immobilization in SLC for 4 to 6 weeks

22. External Fixation Between 20 – 40% are open dislocations Milenkovic S, et al. Injury . 2006: 11 Gustilo II and III subtalar dislocations Follow up 18 – 28 months Outcome E x fix removed 4 – 6 weeks No infection Avascular necrosis = 1 ( Gustilo IIIB medial dislocation) 7 associated fractures Arthrosis = 8 Reduced ROM = 9 Pain with prolonged activity = 8

23. Prognosis

24. Complications Acute Skin necrosis Nerve injury Tibial nerve Lateral dislocation Medial plantar nerve Medial dislocation Chronic Joint stiffness/ ROM Arthritis Chronic pain Instability Avascular necrosis of the talus Reflex sympathetic dystrophy Complications are more frequent in lateral dislocations High trauma energy Higher incidence of associated bone/ osteochondral lesions

25. Prognosis Factors Time to reduction Type of dislocation Soft tissue damage Duration of immobilization Intra-articular fractures associated with poor prognosis 20% complication rate Minimal disability despite subtalar motion loss 80% have restricted ROM 50 – 80% radiographic evidence of arthritis Wagner R, et al. Injury . 2004

26. Prognosis: Open Dislocations Goldner JL, et al. J bone Joint Surg Am . 1995: 15 patients Gustilo Grade 3 I&D followed by reduction and immobilization Mean 18 year follow up Associated injuries: Tibial nerve injury = 10 PTT rupture = 5 PT artery laceration = 5 Articular fx = 12 Navicular fx = 3 Talar dome fx = 3 Malleolar fx = 3 Outcome O steonecrosis of the talus = 5 Triple arthrodesis = 4 Pantalar arthrodesis = 1 STJ arthrosis = 2 STJ arthrodesis = 2 All reported pain in ankle Most had difficulty climbing stairs and walking uneven ground Wagner R, et al. Injury . 2004

27. Prognosis: Closed Dislocations Perugia D, et al. Int Orthop . 2002: 45 patients (37 medial and 8 lateral) Mean follow up of 7.5 years (2-17 years) Treatment Closed reduction, SLC x 4 weeks, aggressive rehab Outcome Mean AOFAS score = 84 No significant difference between medial and lateral Minimal or no limitation to activity 1 STJ arthrodesis due to chronic instability and pain “…pure subtalar dislocation produced by low energy trauma, promptly reduced and immobilized for four weeks has a favorable long-term outcome.”

28. Prognosis: Closed Dislocations Jungbluth P, et al. J Bone Joint Surg Am . 2010: 23 patients (16 medial, 6 lateral, 1 posterior) Mean follow up = 58.3 months Treatment 13 closed reduced 7 open reduction with external fixation NWB 6 weeks with progressive WB and aggressive PT Full weight 10.6 weeks Outcome AOFAS Score Closed = 83.3 Open = 80.9 Mean = 82.3 No differences observed between medial and lateral dislocations No difference in ROM of affected and unaffected side 9 patients Minor degenerative changes No pain or restriction of movement

29. Conclusion

30. Subtalar Dislocations… Uncommon Injury = <2% 88% have concomitant injuries to foot/ankle Prompt reduction is key CT invaluable tool Intra-articular fractures = worse prognosis

31. References

32. References Barg A, Tochigi Y, Amendola A, Phisitkul P, Hintermann B, Saltzmann CL. Subtalar instability: diagnosis and treatment. Foot Ankle Int . 2012; 33(2):151-160. Bibbo C, Lin SS, Abidi N, Berberian W, Grossman M, Gebauer G, Behren FF. Missed and associated injuries after subtalar dislocation: the role of ct. Foot Ankle Int. 2001; 22(4):324-328. Bibbo C, Robert B, Anderson RB, Hodges W, Davis WH. Injury characteristics and the clinical outcome of subtalar dislocations: a clinical and radiographic analysis of 25 cases. Foot Ankle Int . 2003; 24(2)158-163 . Bohay DR, Manoli A II. Occult fractures following subtalar joint injuries. Foot Ankle Int . 1996; 17(3):164-169. Bohay DR, Manoli A II. Subtalar joint dislocations. Foot Ankle Int . 1995; 16(12):803-808 . Conesa X, Barro V, Barastegui D, Batalla L, Tomas J, Molero V. Lateral subtalar dislocation associated with bimalleolar fracture: case report and literature review. J Foot Ankle Surg . 2011; 50(5):612-615 .

33. References DeLee JC, Curtis R. Subtalar dislocation of the foot. J Bone Joint Surg Am . 1982; 64(3):433-437 . de Palma L, Santucci A, Marinelli M. Irreducible isolated subtalar dislocation: a case report. Foot Ankle Int . 2008; 29(5): 523-526 . Goldner JL, Poletti SC, Gates HS III, Richardson WJ. Severe open subtalar dislocations. Long-term results. J Bone Joint Surg Am . 1995; 77(7):1075-1079 . Heck BE, Ebraheim NA, Jackson WT. Anatomical considerations of irreducible medial subtalar dislocation. Foot Ankle Int . 1996; 17(2):103-106 . Horning J, DiPretaJ . Subtalar Dislocation. Orthopedics . 2009; 32(12 ):904-908. Hyder N, Jones S, Nair B. Medial subtalar dislocation. The Foot . 1997; 7:34-36. Jungbluth P, Wild M, Hakimi M, Gehrmann S, Djurisic M, Windolf J, Muhr G, Kälicke T. Isolated subtalar dislocation. J Bone Joint Surg Am . 2010; 92:890-894.

34. References Lasanianos NG, Lyras DN, Mouzopoulos G, Tsutseos N, Garnavos C. Early mobilization after uncomplicated medial subtalar dislocation provides successful functional results. J Orthop Traumatol . 2011: 12(1):37-43. Love JN, Dhindsa HS, Hayden DK. Subtalar dislocation: evaluation and management in the emergency department. J Emer Med . 1995; 13(6):787-793. Merchan ECR. Subtalar dislocations: long-term follow-up of 39 cases. Injury . 1992; 23(2):97-100. Milenkovic S, Mitkovic M, Bumbasirevi . External fixation of open subtalar dislocation. Injury. 2006; 37(9): 909-913. Perugia D, Basile A, Massoni C, Gumina S, Rossi F, Ferretti A. Conservative treatment of subtalar dislocations. Int Orthop . 2002; 26(1):56-60 .

35. References Pesce D, Wethern J, Patel P. Rare case of medial subtalar dislocation from a low-velocity mechanism. J Emer Med . 2008; 41(6):121-124. Sanders DW. Fractures of the talus. In: Bucholz RW, Heckman JD, Court-Brown C, eds. Rockwood and Green’s Fractures in Adults . Vol 1. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2006:2249-2292 . Tucker DJ, Burian G, Boylan J. Lateral subtalar dislocation: review of the literature and case presentation. J Foot Ankle Surg . 1998; 37(3):239-247 . Wagner R, Blattert TR, Weckbach A. Talar dislocations. Injury . 2004; 35(Suppl2):SB36-45. Waldrop J, Ebraheim NA, Shapiro P, Jackson WT. Anatomical considerations of posterior tibialis tendon entrapment in irreducible lateral subtalar dislocation. Foot Ankle . 1992; 13(8):458-461.

36. Thank You