Locking compression hip screw

• US 20070270847A1
• Filed: 04/28/2006
• Published: 11/22/2007
• Est. Priority Date: 04/28/2006
• Status: Active Grant

• Current Assignee: James Shaw
• Original Assignee: James Shaw
• Inventors: Shaw, James
• Granted Patent: US 7,503,919 B2
• Time in Patent Office: Days
• US Class Current: 606/65
• CPC Class Codes: A61B 17/746 the longitudinal elements coupled to a plate opposite the femoral head

Abstract

A modification to the prototypical compression (dynamic or sliding) hip screw is described which expands the utility and surgical indications of this frequently used fracture fixation device to include the fracture pattern commonly referred to as a “reverse obliquity fracture” of the proximal femur. This fracture pattern is poorly secured with current generation hip screws, frequently necessitating the use of intramedulary fracture fixation devices or external fixation hardware. The described modification blocks telescopic sliding of the femoral head lag screw within the cylindrical barrel of the side plate and allows for secure locking of the lag screw within the side plate, preventing any relative motion between the screw and plate once fracture reduction has been achieved. In a locked mode, the proximal fracture fragment(s) is prevented from displacing laterally relative to the distal (diaphysial) fragment, as occurs commonly when a reverse obliquity fracture or a comminuted intertrochanteric femur fracture is fixed with a conventional hip screw. No change in routine fracture reduction or insertion technique is required to use the Locking Compression Hip Screw. Additionally, the described modification does not preclude use of the Locking Compression Hip Screw in a dynamic or sliding mode, if desired, when used to fix the more common femoral neck or intertrochanteric fracture patterns.

Claims

1. A compression hip screw device for treating proximal femur fractures with a design feature that allows optional locking of the femoral head lag screw within the cylindrical portion of the side plate.

2. The Locking Compression Hip Screw device in claim 1, consisting of four parts:

a) a metallic lag screw of variable length, which is screwed into the femoral neck and head during the course of fracture fixation, consisting of a smooth shank (with or without anti-rotational flats or key-ways) with course cancellous bone threads on the medial end and an axially threaded hole on the lateral end and,

b) a metallic side plate of variable size, length and angulations containing a hollow cylindrical portion (with or without anti rotational flats or key-ways) for sliding interdigitation with the lag screw and an integrally attached plate for screw fixation to the lateral femoral diaphysis and containing a threaded section within the lateral aspect of the cylindrical portion, into which a

c) metallic locking plug is screwed so that it abuts against the lateral end of the interdigitated lag screw to prevent lateral sliding translation of the lag screw within the side plate, and through its hollow central core a

d) metallic compressing screw may be inserted and threaded into the mating female threads of the lag screw and tightened against the locking plug or side plate, such that it pulls the lag screw tightly against the previously inserted plug, preventing sliding translation of the lag screw in either direction.

3. The Locking Compression Hip Screw device in claim 2, which, at the discretion of the operating surgeon, the locking plug and compression screw may be left out, allowing the device to function in an unlocked fashion with unimpeded sliding translation of the lag screw within the cylindrical portion of the side plate, or

the compressing screw may be inserted into the lag screw without the locking plug in place and tightened against the side plate, forcing a lateral translation of the lag screw within the cylindrical portion of the side plate and, as a result, compression of the typical femoral neck or intertrochanteric fracture fragments.