Femoral Component Revision through a DAA THA
The authors describe a unique case of a total hip arthroplasty patient with failure at the modular head neck junction due to trunnion wear that was revised through a direct anterior approach.
Snir Heller MD, and William J. Hozack MD
The authors have no disclosures relevant to this article.
A 61-year-old healthy male was referred for revision right total hip arthroplasty (THA). Eight years prior, he had undergone primary THA for end-stage osteoarthritis, and he had been pain-free for those 8 years.
On the day of admission, he heard a crack upon standing up and felt severe lateral hip pain. A Stryker Trident shell with X3 polyethylene and Accolade TMZF stem with cobalt chromium (CoCr) v-40 head had been used during the primary surgery.
Past Surgical History
- Right THA as described
- Left THA 9 years prior with a similar implant but ceramic-on-ceramic bearing surfaces
- Right leg 1.5 cm shorter than the left
- Right hip pain with all movement
- Swelling of the right lower limb
- Neuromuscular function intact
- Incision intact
- Complete blood count normal
- Erythrocyte sedimentation rate: 18; C-reactive protein: 0.6
- Cobalt – 2.5 (ref 1.8 or less); chromium – 2.1 (ref less than 1.8)
- Radiographs show prosthesis failure at the modular neck-head junction (Figure 1).
Figure 1. Preoperative AP pelvic radiograph showing failure of the right hip prosthesis at the neck-head interface.
- THA implant failure at the neck-head junction
The patient underwent revision THA through the direct anterior approach. Exposure of the hip joint revealed metallosis, dissociation between the head and the neck, severe trunnion damage (Figure 2), and polyethylene damage (Figure 3).
Figure 2. Severe damage to the trunnion due to corrosion reaction.
Figure 3. Damage to the polyethylene liner.
The femoral stem was extracted with the use of an extended trochanteric osteotomy (ETO).
The femoral component was revised to a diaphyseal fixated stem with a Restoration Modular System (RMS; Stryker Orthopaedics, Mahwah, New Jersey) (Figure 4).
Figure 4. Postoperative radiograph with the RMS femoral component.
The patient’s postoperative course was uneventful.
Modular component dissociation is a rare complication of THA. Most of the reported cases of neck-head dissociation are associated with constrained liners or the reduction of dislocations. [1-4] The present case is a unique form of a non-traumatic head-neck dissociation due to excessive trunnion wear as a result of corrosion reaction.
The authors revised the femoral component through the direct anterior approach. The following are technical tips for femur exposure during this procedure:
- The patient is placed supine on a standard operating table. A bump is placed under the anterior superior iliac spine (ASIS) to provide additional hip extension.
- A standard Smith-Peterson approach is made starting 2 cm distal and 2 cm lateral to the ASIS.  The previous incision is incorporated, if possible.
- If the interval is not clearly identified, dissect proximally or distally through healthy tissue to identify the landmarks of the tensor fascia lata (TFL)
- For extended proximal exposure, the TFL can be split toward the ASIS. Make sure to protect the lateral femoral cutaneous nerve. The TFL is repaired as one sleeve during wound closure.
- When distal extension is needed, split the TFL and either split or elevate the vastus lateralis to expose the femur. If greater exposure is needed, the TFL can be detached. 
- For circumferential exposure of the acetabular cup, excise the pseudocapsule.  Change the liner as needed.
- For stem removal, a partial longitudinal ETO with a single longitudinal bone cut may suffice for its release.
- When a formal ETO is needed, use a high-speed burr to avoid a stress riser at the junction of the vertical and horizontal osteotomies.
- Maintain an intact muscle-osseous sleeve to promote healing of the osteotomy. 
- The osteotomy is closed with cables or wires.
Snir Heller, MD, and William J. Hozack, MD, are from The Rothman Institute, Philadelphia, Pennsylvania.
Adult Reconstruction Section Editor, The Rothman Institute Grand Rounds
- Chu CM, Wang SJ, Lin LC. Dissociation of modular total hip arthroplasty at the femoral head-neck interface after loosening of the acetabular shell following hip dislocation. J Arthroplasty. 2001 Sep;16(6):806-9
- Sporer SM, DellaValle C, Jacobs J, Wimmer M. A case of disassociation of a modular femoral neck trunion after total hip arthroplasty. J Arthroplasty. 2006 Sep;21(6):918-21.
- Star MJ, Colwell CW Jr, Donaldson WF 3rd, Walker RH. Dissociation of modular hip arthroplasty components after dislocation. A report of three cases at differing dissociation levels. Clin Orthop Relat Res. 1992 May;(278):111-5
- Chu CM, Wang SJ, Lin LC. Dissociation of modular total hip arthroplasty at the femoral head-neck interface after loosening of the acetabular shell following hip dislocation. J Arthroplasty. 2001 Sep;16(6):806-9.
- Bender B, Nogler M, Hozack WJ. Direct anterior approach for total hip arthroplasty. Orthop Clin North Am 2009;40:321–8
- Mast NH, Laude F. Revision total hip arthroplasty performed through the Hueter interval. J Bone Joint Surg Am 2011;93 Suppl 2:143–8.
- Kennon R, Keggi J, Zatorski LE, Keggi KJ. Anterior approach for total hip arthroplasty: beyond the minimally invasive technique. J Bone Joint Surg Am 2004;86-A Suppl:91–7.
- Younger TI, Bradford MS, Magnus RE, Paprosky WG. Extended proximal femoral osteotomy. A new technique for femoral revision arthroplasty. J Arthroplasty 1995;10:329–38.