Pertrochanteric Hip Fracture Fixation with 3 Hole and 4 Hole DHS Side Plates ‑ A Retrospective Patient Record Review

Abstract

Introduction: Dynamic hip screw fixation (DHS) with a 4‑hole side plate and 4 bi‑cortical screws is considered by many to be the standard implant for extracapsular hip fractures. The 4‑hole side plate, however, has several disadvantages including longer incision, increase in operating time, bleeding and increased wound morbidity. Biomechanical studies have shown that most of the force in a 4‑hole DHS fixation is borne by the proximal three screws. This study (specifically) compares the outcome of fixation using 3‑hole and 4‑hole DHS in extracapsular hip fracture fixations (with the hypothesis being that 3‑hole plate is adequate even in unstable intertrochanteric fractures. Patients and Methods: Atotal of 72 consecutive patients who had DHS fixation with either a 3 hole or 4 hole DHS side plate and who were either directly operated or supervised by a single consultant were recruited. Fractures were classified using the AO fracture classification system as stable (AO/OTA 31A1–31A2.1) and unstable (31A2.2–31A3.3 subtypes) for ease of comparison. Failure was defined as metalwork breakage, nonunion, screw cut‑out or pull out or any other complications of bone healing requiring a revision. Results: A total of 23 patients (68.1%) were female, whereas 49 patients (31.9%) were male. Fractures in 33 patients were classified as stable with the (AO/OTA 31A1–31A2.1) and unstable in 39 patients with (31A2.2–31A3.3 subtypes). Thirty‑three (45.8%) patients had fixation with 3‑hole side plate, whereas 39 (55.2%) patients had fixation with 4‑hole side plate. In the 3 hole group, 17 patients had stable fractures, whereas 16 patients had unstable fracture configuration while in the 4‑hole DHS side plate group, 16 patients had stable fracture configuration, whereas 23 patients had unstable fracture. The mean change in hemoglobin was lower for the 3‑hole DHS group (3 hole‑6.64 g/l versus 4Hole 12.41 g/l) (t = 1.732, P = 0.090, P ≤ 0.05). One patient in each group also had metalwork failure with screw cut‑out through the head and the other being (screw breakage) complete failure of the screw necessitating conversion to total hip arthroplasty. Conclusion: Three‑hole DHS plate offers comparable outcome with its 4‑hole counterpart even with unstable intertrochanteric fractures, with slightly less blood loss and smaller scars.