The Use of a Blocking Screw to Prevent Malalignment of Proximal Third Tibial Shaft Fractures During Intramedullary Naili

1. The Use of a Blocking Screw to Prevent Malalignment of Proximal Third Tibial Shaft Fractures During Intramedullary Nailing By Adam Morse, D.O. Garden City Hospital Garden City, Michigan

2. Introduction • Fractures of the proximal 1/3 of the tibia are relatively rare (5-7%, Lang et al), however, • Malalignment after IM nailing of these fractures has been reported at rates from 58% (Freedman et al) to 84% (Lang et al) • Most authors agree that there is a high learning curve to nailing these fractures

3. Introduction • Numerous Authors have recommended abandoning the IM nail for these fractures including lang et al, 1995 • Others have recommended the following modifications: • Nailing in a semiextended position through a total knee incision: Tornetta & Collins, 1996 • Combining anterior unicortical buttress plating with IM nailing: Mathews et al, 1997

4. Introduction • Reduction of the fracture to within 5 degrees of anatomic has the following theoretical advantages: • returns a more normal range of motion in all planes • increases the rate of union • decreased rate of cosmetic functional deformities • normalizes joint forces to prevent uneven wear and progression of degenerative changes

5. Operative Technique • Pt supine, Tourniquet at 350, knee flexed over a well padded triangle or large bump • 6 cm midline incision is made from the inferior pole of the patella to the tibial tubercle • The medial patellar retinaculum is sharply incised along the border of the tendon • An Anterocentral starting hole in made with an awl after verification of position on both AP and Lateral x-rays

6. Posteriorly Directed Nail Insertion Leads to Apex Anterior Angulation and Posterior Displacement

7. Medial Starting Point Leads to Valgus Angulation and Lateral Displacement

8. Operative Technique • The Nail is then passed with or without a guide wire, and with or without reaming, based on physician preference • The alignment is checked in AP and Lateral planes for angulation and displacement • If the alignment is unacceptable the nail is backed out and a blocking screw is placed prior to reinsertion of the nail • The nail is locked proximally and distally based on physician preference and stability

9. The Blocking Screw • Any screw placed in bone with with the intent of effectively narrowing canal diameter to prevent translation of the nail • It is a concept, not a specific technique, which does not require a specific screw • It can be placed in any bone in any plane which necessitates increased translational stability of the nail in a widened medullary canal

10. The Blocking Screw • It has been successfully utilized in the supracondylar femur fracture, the proximal tibia fracture, and the pilon fracture • In the proximal tibia it is most frequently placed from medial to lateral in the metaphyseal bone as close to the fracture site as good fixation can be achieved • It’s effects are most pronounced in fractures with significant posterior comminution

11. Canal Narrowing with Blocking Screw

12. Apex Anterior Angulation and Posterior Displacement

13. Blocking Screw Placement (AP View)

14. Final Reduction After Blocking Screw Placement

15. Thank You