Session X - Pelvis

*Acetabular Fractures Associated with Femoral Head Fractures (Pipkin IV Injuries): Long-Term Follow-up of Open Reduction and Internal Fixation

Michael Zlowodzki, MD¹; Andrew Thomson, MD¹; George V. Russell, MD²; Philip J. Kregor, MD¹;

¹Vanderbilt University Medical Center, Nashville, Tennessee, USA;

²University of Mississippi Medical Center, Jackson, Mississippi, USA

(a-Synthes, USA; AO Research Foundation)

Purpose: The purpose of this prospective analysis was to delineate the clinical outcome of surgical treatment of acetabular fractures associated with femoral head fractures (Pipkin IV injuries).

Methods: During a 7-year period (1995 to 2002), the senior author operatively treated 445 acetabular fractures. Of these, 12 were associated with a femoral head fracture. Both components of the Pipkin IV injury (posterior wall fracture and femoral head fracture) were treated with open reduction and internal fixation. There were 10 male and 2 female patients, with an average age of 28 years (range, 18 to 48). In 11 of 12 cases there was a posterior hip dislocation, with time to relocation less than 6 hours in 10 cases, and 36 hours in 1 case (irreducible dislocation). The patients were observed in a prospective protocol established for the follow-up of all acetabular fractures. The average follow-up was 28 months (range, 12 to 60). Intraoperative and follow-up data were prospectively entered into a database. The choice of surgical approach was a Ganz trochanteric flip osteotomy in nine cases, Kocher-Langenbeck followed by a Smith-Peterson approach in two cases, and a Kocher-Langenbeck approach alone in one case. Significant intraoperative findings included osteochondral loss from the femoral head in 8 of 12 cases, osteochondral nonreconstructable fragments from the posterior wall in 3 cases, and marginal impaction in 3 cases. Patients were permitted toe-touch weightbearing for 10 to 12 weeks. No heterotopic ossification prophylaxis was used. Postoperative reduction was assessed as anatomical (0 to 1 mm), imperfect (1 to 3 mm), and poor (>3 mm). Patients were followed at yearly postoperative intervals and assessed via AP and Judet radiographs, a modified d'Aubigne/Postel clinical scale (Matta, 1996), and radiographic grade (Matta, 1996).

Results: Of the 12 patients with Pipkin IV injuries, the clinical outcome score was excellent in 4, good in 7, and poor in 1. Radiographic grade was excellent in 7, good in 4, and poor in 1. There were no postoperative infections or sciatic nerve injuries. There was no clinically significant heterotopic ossification. The poor result was in a 48-year old woman who sustained a left sacroiliac joint injury, symphysis pubis disruption, left posterior wall fracture, left infra foveal femoral head fracture, and an irreducible posterior hip dislocation. She underwent open reduction and internal fixation of both injuries with surgical dislocation of the hip and developed significant joint space narrowing by 10 months, necessitating a total hip arthroplasty at 16 months after her injury.

Discussion: Epstein, et al. reported on 55 Pipkin IV injuries in 1985 and noted that only 47% of patients had a good result. Our clinical impression has been that visualization of both injuries is challenging without combined approaches and that this poor visualization has resulted in poor reduction. The Ganz trochanteric flip osteotomy combined with surgical dislocation of the hip allows for optimal visualization and fixation of both injuries, controlled reduction of the hip, and thorough debridement of the hip joint. Our case series demonstrates that acceptable results (92% good or excellent) can be obtained at an average follow-up of 28 months if these principles are followed.

Significance: Pipkin IV injuries are rare and potentially devastating. However, with appropriate and timely anatomical reduction, acceptable results (92% good or excellent) have been achieved.