Orthopedics

Long-term Outcome of Shelf Grafts in Total Hip Arthroplasty for Developmental Hip Dysplasia

Markku T. Nousiainen, BA(Hons), MS, MEd, MD, FRCS(C); Anthony C. Maury, MBChB, MSc, FRCS(T&O); Ali Alhoulei, MD, FRCS(C); David J. Backstein, MD, MEd, FRCS(C); Allan E. Gross, MD, FRCS(C)

Abstract

Primary total hip arthroplasty (THA) in patients with osteoarthrosis secondary to developmental hip dysplasia is often complex due to anterolateral acetabular bone deficiency. The use of femoral head (shelf) autograft during the index arthroplasty provides nonimmunogenic, osteoconductive support with the potential for enhanced bone stock should revision surgery be required. Few long-term studies document the outcome of the use of shelf grafts in primary THA or quantify the need for further bone graft at revision surgery.

A retrospective analysis was conducted of a single surgeon’s series of 31 THAs performed in 25 patients with developmental hip dysplasia. Postoperative biplanar radiographic analysis was performed at 3 and 6 months and annually thereafter for a mean of 14 years (range, 8-18 years). Grafts were assessed for union, resorption, and displacement. The need for acetabular bone graft at revision surgery was recorded. Bony union was observed in 93% of cases; fibrous union developed in the remaining 7%. There was no graft displacement. In 71% of cases, less than one-third of the graft had resorbed; one-third to one-half had resorbed in the remaining 29% of cases. Of 10 patients revised (all for loosening of the acetabular component), 2 required structural allograft for inadequate bone stock.

Femoral head autograft allows effective acetabular coverage with excellent rates of union, exhibits minimal graft resorption in the long-term, and rarely requires further acetabular allograft in revision surgery.

Primary total hip arthroplasty (THA) in patients with osteoarthrosis secondary to developmental hip dysplasia is often complex due to anterolateral acetabular bone deficiency. Surgical options that manage this problem include use of a high hip center,1 placement of the acetabular component in a medialized or protruded position,2 or structural bone grafting to the superolateral aspect of the acetabulum (shelf graft).3

Shelf autograft provides a nonimmunogenic, osteoconductive lateral support with the potential for enhanced bone stock should revision surgery be required. The technique has been shown in some series to give reliable early clinical results,4 and series reporting results in the longer term show promising results as well.3,5-10 This study reports on the long-term performance (mean, 14 years) of the senior author’s (A.E.G.) series of shelf grafts in terms of radiological outcome and the need for further bone graft at revision surgery. This study aimed to report initial graft union rate, quantify long-term graft resorption, and quantify the need for further acetabular bone graft in patients requiring revision THA.

A retrospective analysis was conducted of a single surgeon’s (A.E.G.’s) consecutive series of 31 THAs in 26 patients with developmental hip dysplasia. This is a long-term report on the surgeon’s previously reported series.3 Each patient had undergone THA with an uncemented acetabular component in conjunction with a bulk femoral head autograft to supplement anterolateral coverage of the acetabular component. The same surgical technique as has been previously described was used.3,11

Using the obturator foramen as a landmark, the acetabular component was placed at the correct or nearly correct anatomic level. After the level for cup placement was identified, reaming was started with a 36-mm reamer. A drill hole was made through the medial part of the acetabulum and a depth gauge was used to determine how deep to ream. Reaming stopped at 5 to 10 mm from the inner cortex. A trial cup was then inserted, and, if <70% of the cup was found to be uncovered, shelf bulk femoral head autograft was used. The cartilage was reamed off but the subchondral bone was kept intact. The graft was placed at the superior edge of the acetabulum or just inside it and was fixed with two 4.5-mm cancellous screws. The screws were placed…

Abstract

Primary total hip arthroplasty (THA) in patients with osteoarthrosis secondary to developmental hip dysplasia is often complex due to anterolateral acetabular bone deficiency. The use of femoral head (shelf) autograft during the index arthroplasty provides nonimmunogenic, osteoconductive support with the potential for enhanced bone stock should revision surgery be required. Few long-term studies document the outcome of the use of shelf grafts in primary THA or quantify the need for further bone graft at revision surgery.

A retrospective analysis was conducted of a single surgeon’s series of 31 THAs performed in 25 patients with developmental hip dysplasia. Postoperative biplanar radiographic analysis was performed at 3 and 6 months and annually thereafter for a mean of 14 years (range, 8-18 years). Grafts were assessed for union, resorption, and displacement. The need for acetabular bone graft at revision surgery was recorded. Bony union was observed in 93% of cases; fibrous union developed in the remaining 7%. There was no graft displacement. In 71% of cases, less than one-third of the graft had resorbed; one-third to one-half had resorbed in the remaining 29% of cases. Of 10 patients revised (all for loosening of the acetabular component), 2 required structural allograft for inadequate bone stock.

Femoral head autograft allows effective acetabular coverage with excellent rates of union, exhibits minimal graft resorption in the long-term, and rarely requires further acetabular allograft in revision surgery.

Primary total hip arthroplasty (THA) in patients with osteoarthrosis secondary to developmental hip dysplasia is often complex due to anterolateral acetabular bone deficiency. Surgical options that manage this problem include use of a high hip center,1 placement of the acetabular component in a medialized or protruded position,2 or structural bone grafting to the superolateral aspect of the acetabulum (shelf graft).3

Shelf autograft provides a nonimmunogenic, osteoconductive lateral support with the potential for enhanced bone stock should revision surgery be required. The technique has been shown in some series to give reliable early clinical results,4 and series reporting results in the longer term show promising results as well.3,5-10 This study reports on the long-term performance (mean, 14 years) of the senior author’s (A.E.G.) series of shelf grafts in terms of radiological outcome and the need for further bone graft at revision surgery. This study aimed to report initial graft union rate, quantify long-term graft resorption, and quantify the need for further acetabular bone graft in patients requiring revision THA.

Materials and Methods

A retrospective analysis was conducted of a single surgeon’s (A.E.G.’s) consecutive series of 31 THAs in 26 patients with developmental hip dysplasia. This is a long-term report on the surgeon’s previously reported series.3 Each patient had undergone THA with an uncemented acetabular component in conjunction with a bulk femoral head autograft to supplement anterolateral coverage of the acetabular component. The same surgical technique as has been previously described was used.3,11

Using the obturator foramen as a landmark, the acetabular component was placed at the correct or nearly correct anatomic level. After the level for cup placement was identified, reaming was started with a 36-mm reamer. A drill hole was made through the medial part of the acetabulum and a depth gauge was used to determine how deep to ream. Reaming stopped at 5 to 10 mm from the inner cortex. A trial cup was then inserted, and, if <70% of the cup was found to be uncovered, shelf bulk femoral head autograft was used. The cartilage was reamed off but the subchondral bone was kept intact. The graft was placed at the superior edge of the acetabulum or just inside it and was fixed with two 4.5-mm cancellous screws. The screws were placed in an oblique-to-vertical direction. The subchondral surface of the autograft faced the soft tissue while the cancellous surface abutted the cup. In addition, a flying-buttress graft consisting of cancellous, morsellized, autogenous bone was routinely placed between the top of the shelf graft and ilium. The ilium at the junction and just proximal to the shelf graft was roughened or perforated with multiple small drill holes to encourage union and remodeling (Figure 1).

Figure 1: Illustration of a shelf autograft fixed with 2 cancellous screws

Figure 1: Illustration of a shelf autograft fixed with 2 cancellous screws placed in a vertical-to-oblique direction. Note the flying-buttress graft consisting of morsellized autograft bone. (Reprinted with permission from Gross AE, Solomon M. The flying buttress acetabular bone-graft. J Arthroplasty. 1997; 12(6):706-708. Copyright © 1997 Elsevier.)

In all cases, biplanar radiographic analysis was performed postoperatively at 3 and 6 months and annually thereafter for a mean of 14 years (range, 8-18 years). Pre- and postoperative radiographs of a typical case of an arthritic hip with developmental hip dysplasia treated with THA and shelf graft acetabular augmentation are shown in Figure 2.

To assess bone graft union, anteroposterior and lateral radiographs were analyzed for the presence of bony trabeculae crossing the graft–ilium junction site. To assess graft resorption, the classification of Gerber and Harris was used.4 The clinical record was reviewed to assess whether further bone grafting of the acetabulum was necessary at the time of revision surgery.

Figure 2A: Developmental hip dysplasia and secondary arthritis Figure 2B: Radiograph of the same patient 10 years postoperatively with shelf autograft

Figure 2: Preoperative radiograph of a 44-year-old woman with developmental hip dysplasia and secondary arthritis (A). Radiograph of the same patient 10 years postoperatively with shelf autograft (B).

Results

The cohort of patients included 7 men and 18 women. Mean patient age was 61 years (range, 22-82 years). Using the classification of Hartofilakidis et al,2 19 hips (61.2%) were type 1 (hip contained within original acetabulum), 8 hips (25.8%) were type 2 (lower lip of false acetabulum contacted upper lip of original acetabulum), and 4 hips (13%) were type 3 (no contact between original and false acetabulum).

Mean follow-up was 14 years (range, 8-18 years). At follow-up, there was no evidence of graft displacement in any case. Bony union of the shelf graft occurred in 29 of 31 cases (rate of union, 93%). The 2 other cases achieved a fibrous union. Twenty-two cases (71%) exhibited mild resorption; 9 cases (29%) exhibited moderate resorption. No cases exhibited severe resorption.

Ten patients underwent revision surgery of their acetabular component. In all cases, the reason for revision was aseptic loosening of the implant. Two hips underwent revision 9 years after the index procedure, 2 hips had revision surgery between 10 and 15 years after the index procedure, and 6 cases had revision surgery >15 years after the index procedure. With revision of the acetabulum as the endpoint, survival was 68% at a mean 14 years. Of these 10 cases, 2 required structural allograft for inadequate acetabular bone stock.

Discussion

Harris et al12 originally described the use of femoral head shelf autograft for reconstruction of the acetabulum for THA in developmental hip dysplasia. Since that time, several studies have reported encouraging early, mid-, and long-term results when either cemented12,13 or cementless cups3-5,14 have been used.

The present study’s findings are consistent with other studies describing the long-term outcomes of shelf autograft in uncemented acetabular components. Hendrich et al9 reported an 11-year survival rate of 91.6% and 88.9% for revision and loosening, respectively, in 56 uncemented cups. At 11-year follow-up, Farrell et al7 reported that 5 of 28 cups (17.9%) had undergone revision. Only 2 of these cases were found to have substantial graft resorption that required further bone grafting at the time of revision surgery. Hampton and Harris15 reported on the use of cementless cups for severe developmental hip dysplasia at an average follow-up of 16 years in 20 hips. The survivorship for the shell was 92%. All grafts united with <25% resorption, and all cups were well fixed.

Considering these results, shelf grafts have the potential to enhance acetabular bone stock at revision surgery. Our findings of only 2 of 10 revision cases requiring further structural allograft for the acetabulum at the time of revision surgery are in keeping with the literature. While no technique of dealing with the acetabular component in a THA for developmental hip dysplasia is ideal, femoral head shelf autograft provides effective acetabular coverage with an excellent rate of union, minimal graft resorption in the long term, and improved bone stock should revision surgery be required.

References

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  2. Hartofilakidis G, Stamos K, Karachalios T, Ioannidis TT, Zacharakis N. Congenital hip disease in adults. Classification of acetabular deficiencies and operative treatment with acetabuloplasty combined with total hip arthroplasty. J Bone Joint Surg Am. 1996; 78(5):683-692.
  3. Morsi E, Garbuz D, Gross AE. Total hip arthroplasty with shelf grafts using uncemented cups. A long-term follow-up study. J Arthroplasty. 1996; 11(1):81-85.
  4. Gerber SD, Harris WH. Femoral head autografting to augment acetabular deficiency in patients requiring total hip replacement. A minimum five-year and an average seven-year follow-up study. J Bone Joint Surg Am. 1986; 68(8):1241-1248.
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  8. Shetty AA, Sharma P, Singh S, Tindall A, Kumar SV, Rand C. Bulk femoral-head autografting in uncemented total hip arthroplasty for acetabular dysplasia: Results at 8 to 11 years follow-up. J Arthroplasty. 2004; 19(6):706-713.
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Authors

Dr Nousiainen is from Holland Orthopaedic and Arthritic Centre, Sunnybrook Health Sciences Centre, and Drs Maury, Alhoulei, Backstein, and Gross are from the Division of Orthopedic Surgery, Mount Sinai Hospital, Toronto, Ontario, Canada.

Drs Nousiainen, Maury, Alhoulei, Backstein, and Gross have 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: Allan E. Gross, MD, FRCS(C), Division of Orthopedic Surgery, Mount Sinai Hospital, 600 University Ave, Ste 476A, Toronto, Ontario, Canada M5G 1X5.

DOI: 10.3928/01477447-20090728-15

10.3928/01477447-20090728-15

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