Reconstruction of the femur depends on the quantity of bone loss and the quality of the remaining bone stock. Multiple classifications and reporting systems can be used to characterize the bone defect. We present a simple algorithmic approach for proximal femoral bone loss reconstruction during revision total hip arthroplasty. Quantity of bone loss is assessed using radiographs based on different classification systems, whereas quality of the remaining bone stock is assessed intraoperatively. Based on the type of proximal bone loss and the quality of the available bone, we describe our preferred reconstruction technique.
For minor bone loss, the metaphysis is expanded but intact with partially absent calcar. There is minimal bone loss anteriorly and posteriorly, and the diaphysis is intact. For significant bone loss, the metaphysis is compromised, and there is no calcar. There is minimal bone loss anteriorly and posteriorly. The available proximal bone may be thin, sclerotic, and incapable of support. However, the diaphysis is intact. For massive bone loss, there is complete circumferential bone loss in the metaphysis, extending to the diaphysis. The anterolateral bone and supporting subtrochanteric metaphyseal bone are absent. The metaphysis is not stable and will not offer rotational stability. There is massive bone loss anteriorly and posteriorly. The stability of the implant is dependent on distal diaphyseal fixation. For complete proximal bone loss, there is extensive circumferential segmental bone loss proximally and extensive cavitary loss involving the entire diaphysis. Additionally, there is extensive ectasia of the diaphysis.
Total hip arthroplasty (THA) revision procedures have increased in volume significantly in the past decade.1 Revision of the femoral component and its reconstruction is a complex procedure that has shown improved outcomes with enhanced technology and the availability of different prosthetic options. To characterize the bone defect, multiple classifications and reporting systems have been described.2-4 Different options have been described to reconstruct the femoral bone defect during THA revision.3,5,6 Reconstruction of the femur depends on the quantity of bone loss and the quality of the remaining bone stock. A systematic approach to address the femoral bone defect using the current available options, based on the classification systems, may improve the reproducibility of good results and outcomes of THA revision.
The main goals of revision surgery are aimed at decreasing pain and improving function by using a stable construct that restores the hip biomechanics while preserving the bone and soft tissues, augmenting bone when necessary and, in some cases, providing a foundation for possible additional future procedures. This article presents a simple algorithmic approach for proximal femoral bone loss reconstruction during THA revision (Figure 1).
Figure 1: The algorithmic approach is summarized in the chart flow.
Classification Systems for Femoral Bone Loss
Multiple classifications and reporting systems have been described to characterize femoral bone loss.2-4 The main purpose of these classification systems is to describe the quantity and location of the remaining bone after bone loss in a standardized manner. Based on both quantity and location of the remaining bone, different reconstructive approaches can be used. Adequate radiographs, including anteroposterior (AP) views of the pelvis and AP and lateral views of the involved hip, are imperative in assessing bone loss. However, radiographs are not the most accurate method to assess bone quantity or quality. Computed tomography (CT) scans have been reliable for assessing bone loss,7 but logistically it may be difficult to obtain for every patient undergoing THA revision, and the metallic artifact when obtaining CT scans in the presence of previous arthroplasty may be a potential limiting factor. In complex cases where the quantity of bone loss is difficult to assess with radiographs, the use of CT scan images with metallic artifact subtraction may be a helpful alternative for the preoperative planning.
The algorithmic approach described in this article is based on the classification systems described by DAntonio et al2 and Longjohn and Dorr8 to characterize bone loss:
- Type 1. Minor bone loss: The metaphysis is expanded but intact with partially absent calcar. There is minimal bone loss anteriorly and posteriorly, and the diaphysis is intact.
- Type 2. Significant bone loss: The metaphysis is compromised, and there is no calcar. There is minimal bone loss anteriorly and posteriorly. The available proximal bone may be thin, sclerotic, and incapable of support. However, the diaphysis is intact.
- Type 3. Massive bone loss: There is complete circumferential bone loss in the metaphysis, extending to the diaphysis. The anterolateral bone and supporting subtrochanteric metaphyseal bone are absent. The metaphysis is not stable and will not offer rotational stability. There is massive bone loss anteriorly and posteriorly. The stability of the implant is dependent on distal diaphyseal fixation.
- Type 4. Complete proximal bone loss: There is extensive circumferential segmental bone loss proximally and extensive cavitary loss involving the entire diaphysis. Additionally, there is extensive ectasia of the diaphysis.
Proximal Femoral Bone Loss Algorithmic Approach in THA Revision
The algorithmic approach to address proximal femoral bone loss during revision THA depends on 2 main factors: the quantity and the quality of the bone available for reconstruction. Quantity is assessed on radiographs and using the above classification system, whereas quality is usually assessed intraoperatively. When there is intact or minimal bone loss proximally (types 1, 2), the reconstructive options depend more heavily on the quality of bone: If there is good bone quality, we use a proximally fixed stem, which usually is modular. This allows loading the proximal bone more physiologically (Figure 2). In a previous publication,we reported the results of using a modular stem in a cohort of 53 patients that underwent 55 THA revision procedures.9 We found significant postoperative improvements in the Harris Hip Scores and SF-12 (Physical and Mental Composite scores) at an average follow-up of 2.5 years. A small number of complications were reported.
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Figure 2: Radiograph of the left hip in a 78-year-old man with aseptic loosening and minimal proximal bone loss with good quality (type 1; A). Radiograph following reconstruction with a proximally-fixed modular stem (B). This particular modular stem (AccuMatch M-Series; Exactech, Gainesville, Florida) allows for seating regardless of the bow of the femur. A coronal slot (white arrow) allows the use of this stem without performing a transverse osteotomy to correct the femur deformity.
Alternately, if the bone quality is not good we use either a modular or nonmodular distally-fixed stem (Figure 3). Patel et al10 described a series of 84 patients who underwent THA revision using this technique. The main reported cause of revision was aseptic loosening. Patients femoral bone loss was classified according to the Paprosky classification.3 Most of the patients were type IIIA, IIIB, and IV. All patients had significant improvement of Harris Hip Score and SF-12 scores postoperatively. Seventeen patients (23.4%) had subsidence, and, of those, 6 did not stabilize and required revision. Undersizing of the femoral stem was the main cause of failure. This situation can be avoided with better fitting of the canal. It is essential to fill the canal completely with the stem when using this technique with conical type stems. This was found to be the main factor to prevent subsidence. Finally, it was reported that higher Paprosky classification types correlated with higher complication rates.
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Figure 3: Patient without an intact sleeve but with minimally preserved proximal bone (type 2; A). Reconstruction with a distally fixed modular stem (Restoration Modular System; Stryker Orthopaedics, Mahwah, New Jersey; B). The preservation of the proximal bone may allow for proximal bone ingrowth and decrease stresses on the modular junction.
If there is major bone loss proximally (types 3, 4) several options exist, as follows:
- Allograft prosthetic composite: We use allograft prosthetic composite in young and active patients who may require additional procedures in the future. The main goal of the allograft prosthetic composite is to recover function and preserve bone stock. This procedure is performed by cementing a press-fit prosthesis proximally into the allograft and then press-fitting the distal portion into the bone (Figure 4).
- Tumor prosthesis: We use tumor prosthetics in older and less active patients with severe bone loss (type 4) and when biologic proximal ingrowth is not possible (Figure 5).
- Distally-fixed stem: This may be nonmodular or modular depending on the necessity to adjust the neck version. It is important to note that with the use of distally fixed modular stems with proximal bone loss, we recommend that enough bone be present to get some ingrowth proximal to the taper junction to reduce stresses at the modular interface. If this is not possible, we would augment the reconstruction with strut grafts. Segmental defects on the diaphysis may need cortical strut graft and cerclage wiring; and cavitary defects may need impaction grafting (Figure 6).
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Figure 6: A 72-year-old man with aseptic loosening and osteolysis, but intact sleeve of diaphyseal bone (A). Reconstruction with a distally-fixed modular stem (Restoration Modular System; Stryker Orthopaedics, Mahwah, New Jersey), supplemented with cortical strut grafts and cerclage wiring (B). Preserved bone stock may allow for proximal bone ingrowth and decrease the stress on the taper.
The main factors that dictate reconstruction options are quantity and quality of the bone. Establishing the type of bone loss before the revision will allow selection of the best implant. Planning ahead is essential to assure that different options are available at the time of surgery. This algorithmic approach provides a simple reconstruction guide for patients undergoing revision THA with proximal femoral bone loss.
- 1. Kurtz SM, Ong KL, Schmier J, Zhao K, Mowat F, Lau E. Primary and revision arthroplasty surgery caseloads in the United States from 1990 to 2004. J Arthroplasty. 2009; 24(2):195-203.
- DAntonio J, McCarthy JC, Bargar WL, et al. Classification of femoral abnormalities in total hip arthroplasty. Clin Orthop Relat Res. 1993; (296):133-139.
- Della Valle CJ, Paprosky WG. The femur in revision total hip arthroplasty evaluation and classification. Clin Orthop Relat Res. 2004; (420):55-62.
- Johnston RC, Fitzgerald RH Jr, Harris WH, Poss R, Muller ME, Sledge CB. Clinical and radiographic evaluation of total hip replacement. A standard system of terminology for reporting results. J Bone Joint Surg Am. 1990; 72(2):161-168.
- Cameron HU. The long-term success of modular proximal fixation stems in revision total hip arthroplasty. J Arthroplasty. 2002; 17(4 Suppl 1):138-141.
- Weeden SH, Paprosky WG. Minimal 11-year follow-up of extensively porous-coated stems in femoral revision total hip arthroplasty. J Arthroplasty. 2002; 17(4 Suppl 1):134-137.
- Park JS, Ryu KN, Hong HP, Park YK, Chun YS, Yoo MC. Focal osteolysis in total hip replacement: CT findings. Skeletal Radiol. 2004; 33(11):632-640.
- Longjohn D, Dorr L. Bone stock loss and allografting: femur. In: Bono JV, ed. Revision Total Hip Arthroplasty. New York: Springer; 1999:100-111.
- Higuera CA, Hanna G, Florjancik K, Allan DG, Robinson R, Barsoum WK. The use of proximal fixed modular stems in revision of total hip arthroplasty. J Arthroplasty. 2006; 21(4 Suppl 1):112-116.
- Patel P, Klika AK, Krebs VE, Barsoum WK. The use of distally-fixed modular stems in total hip arthoplasty. Paper presented at: 26th Annual Meeting Mid-America Orthopaedic Association; April 16-20, 2008; Orlando, FL.
Drs Higuera and Barsoum are from the Department of Orthopedic Surgery, Cleveland Clinic, Cleveland, Ohio; and Dr Capello is from the Department of Orthopedic Surgery, Indiana University, Indianapolis, Indiana.
Dr Barsoum has received royalties from Exactech, Inc, Wright Medical, and SS White; has received research funding from Stryker, Zimmer, Smith & Nephew, Tissuelink, American Geriatrics Society, and OREF; and is a consultant for Stryker, Wright Medical, and SS White. Dr Capello is a consultant for Stryker. Dr Higuera has no relevant financial relationships to disclose.
Presented at Current Concepts in Joint Replacement 2008 Winter Meeting; December 10-13, 2008; Orlando, Florida.
Correspondence should be addressed to: Carlos A. Higuera, MD, 9500 Euclid Ave, A41, Cleveland, OH 44195.