Arthroscopic Treatment of Slipped Capital Femoral Epiphysis Screw Impingement and Concomitant Hip Pathology Elizabeth A. Howse, M.D., Benjamin M. Wooster, B.S., Sandeep Mannava, M.D., Ph.D., Brad Perry, B.S., and Allston J. Stubbs, M.D., M.B.A.
Abstract: Impingement caused by screws used for stabilization of slipped capital femoral epiphysis can be treated arthroscopically. Although troublesome screws have traditionally been removed by open techniques, arthroscopic removal can successfully be achieved. In addition to affording the patient the beneﬁts of minimally invasive surgery, surgeons also have the ability to arthroscopically address any concomitant hip pathology responsible for pain, including femoroacetabular impingement and labral tears.
lipped capital femoral epiphysis (SCFE) is the most common form of hip pathology in adolescents, with consequential changes in anatomy predisposing the hip to further pathologic processes.1-4 Both the deformity of the proximal femur and the hardware used to repair this defect can result in femoroacetabular impingement, causing prolonged pain and disability.3-6 To our knowledge, there have been no studies describing the role of hip arthroscopy as an option to treat iatrogenic impingement in previously surgically corrected SCFE hips.
Surgical Technique Patients may be given a lumbar plexus sciatic regional block to achieve regional anesthesia and are then brought to the operating room, where general From the Department of Emergency Medicine, Long Island Jewish Medical Center, Hofstra North Shore-LIJ School of Medicine (E.A.H.), New Hyde Park, New York; Wake Forest University School of Medicine (B.M.W., B.P.) and Department of Orthopaedic Surgery, Division of Sports Medicine, Wake Forest University School of Medicine (S.M., A.J.S.), Winston-Salem, North Carolina, U.S.A. The authors report the following potential conﬂict of interest or source of funding: S.M. receives support from Wake Forest Innovations Spark Award; Orthopaedic Research and Education Foundation OREF Resident Clinician Scientist Award. A.J.S. receives support from Smith & Nephew Endoscopy, Bauerfeind, Johnson & Johnson shareholder. Received February 20, 2014; accepted May 20, 2014. Address correspondence to Allston J. Stubbs, M.D., M.B.A., Department of Orthopaedic Surgery, Wake Forest University School of Medicine, Medical Center Boulevard, Winston Salem, NC 27157, U.S.A. E-mail: [email protected]
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anesthesia with complete paralysis is induced. Each patient was placed in the modiﬁed supine position on a fracture table (OrthoVision; Steris, Mentor, OH). Under ﬂuoroscopic guidance, the operative hip was carefully and gently distracted, prepared, and draped according to standard protocol. Two primary working portals, anterolateral and modiﬁed anterior, were used. A 70 arthroscope was placed in the anterolateral portal, and dynamic assessment of the femoroacetabular articulation of the hip was conducted. Each pathologic hip showed abutment between the rim of the acetabulum and the SCFE screw (Figs 1 and 2). A hexagonal screwdriver (Smith & Nephew, Andover, MA) was then placed in the anterolateral portal. The screw (as well as the washer when applicable) was subsequently removed under direct visualization with the hip out of traction and positioned in 40 to 50 of ﬂexion. Each screw was advanced one-quarter to one-half turn before removal. In one case a Nitinol guidewire (Smith & Nephew) was threaded through the cannulated portion of the screw to assist with removal. In one patient bony overgrowth over the screw head was visualized and required removal with a 5.5-mm burr, pituitary rongeur, and arthroscopic angulated elevator (Smith & Nephew) before screw removal. Fluoroscopy was used after screw removal to conﬁrm that there was no evidence of retained hardware. Continued abutment of the head-neck junction with the acetabular rim was then addressed using an arthroscopic shaver and arthroscopic burr to achieve a gentle tapered femoroplasty without step-off or notching. The surgical technique is demonstrated in Video 1. Additional forms of pathology were also identiﬁed and subsequently addressed. Labral tears were repaired by the Iberian
Arthroscopy Techniques, Vol 3, No 4 (August), 2014: pp e515-e517
E. A. HOWSE ET AL.
Fig 1. (A) Anteroposterior and (B) lateral intraoperative radiographs of a left hip. Screw prominence is best demonstrated on the lateral radiograph (arrow) with decreased anterior femoral headneck offset, possible screw cam formation, and cephalad retrograde acetabular morphology.
suture technique.8 If dynamic examination showed continued conﬂict between the acetabulum and femoral head, then additional decompression was performed along the acetabulum and femoral head-neck junction. Postoperative rehabilitation was individualized based on the additional arthroscopic procedures performed, with protected weight bearing for all patients for 2 weeks to 8 weeks based on the treatment of concomitant pathology.
Discussion Impingement resulting from surgical ﬁxation of SCFE was recognized as early as 1936 and until recently has been treated by open procedures.9 As hip arthroscopy has gained popularity over the past few decades, the indications for arthroscopic treatment of hip pathology have grown exponentially, including treatment of pathology associated with the pediatric hip.5 Stabilization with in situ single-screw ﬁxation is currently the recommended treatment for SCFE to prevent slippage progression.1,6 Stabilization alone, however, may not relieve symptoms completely. Femoroacetabular impingement can be due to the deformity of the proximal femur associated with SCFE but may also develop as a consequence of the treatment.1,4,6 Goodwin et al.6 showed that
the head of the screw could abut with the acetabular rim in the case of an 11-year-old girl and 2 cadaveric hips. They proposed screw placement lateral to the intertrochanteric line as opposed to perpendicular to the physis as a potential method to reduce the risk of ensuing impingement, but they recognized that this is not always possible. Leunig et al.3 presented 3 cases in which they performed simultaneous correction of both the capital alignment and its associated impingement. They performed in situ ﬁxation of the SCFE followed by immediate arthroscopic osteoplasty to eliminate the prominence of the anterior metaphysis and reshape the femoral head-neck junction. Although all 3 patients had positive outcomes, Leunig et al. recognized that the arthroscopic correction of deformity is technically difﬁcult. Consequently, they recommended that the procedure should only be performed by an experienced hip arthroscopist and not necessarily by the surgeon performing the pinning, which may not always be feasible. Furthermore, although immediate osteoplasty may correct the associated anatomic pathologic impingement, thereby eliminating the need for additional femoroplasty, it cannot address the potential iatrogenic impingement caused by a prominent screw head. Traditionally, these problematic screws have been
Fig 2. (A) Preoperative and (B) intraoperative radiographs of a right hip showing early arthritis with the saber tooth sign7 (ST) and screw abutment against the acetabulum (arrow).
SCFE SCREW IMPINGEMENT Table 1. Advantages and Disadvantages of Arthroscopic Removal of SCFE Screws Advantages
Ability to address concomitant hip pathology Direct visualization Minimize need for intraoperative ﬂuoroscopy Dynamic examination
Risks of hip distraction Screw breakage Failure of removal Learning curve of arthroscopy
removed by open techniques; however, we believe that the described arthroscopic technique yields better clinical outcomes because it allows offending hardware removal in a minimally invasive manner. The speciﬁc advantages and disadvantages of arthroscopic screw removal are detailed in Table 1. Further studies are required to determine its long-term efﬁcacy regarding patient return to function and development of osteoarthritis.
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