The Use of Impaction Bone Grafting in Total Hip Arthroplasty Following Acetabular Fractures

Islam Nassar¹, Sameh Marei², Ahmad Zayda², Ahmed Zaki³ & Elsayed Morsi^4*

¹Specialist of Orthopedic Surgery, Department of Orthopedic Surgery, Faculty of Medicine, Alexandria University, Egypt
²Lecturer of Orthopedic Surgery, Department of Orthopedic Surgery, Faculty of Medicine, Menoufia University, Egypt
³Teaching Assistant of Analytical & Pharmaceutical Chemistry,Department of Analytical & Pharmaceutical Chemistry, Faculty of Pharmacy and Drug Manufacturing, Pharos University, Egypt
⁴Professor and Head of Orthopedic Surgery Department, Department of Orthopaedic Surgery, Menoufia University, Egypt

*Correspondence to: Dr. Elsayed Morsi, Professor and Head of orthopedic surgery Department, Department of Orthopaedic Surgery, Menoufia University, Egypt.

Copyright © 2019 Dr. Elsayed Morsi, et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Introduction
The major cause of failure in total hip arthroplasty is aseptic loosening, which is usually accompanied with bone loss. Bone loss is a major concern of revision total hip arthroplasty (THA). While the problem is easier on the femoral side by passing the defect by long stems, the problem on the acetabular side is more difficult due to the need of restoration of the bone stock and restoration of the hip biomechanics [1]. Acetabular bone deficiencies can be managed with biological techniques (namely bone grafting), and can be managed by modular augments in patients who are unlikely to undergo further revisions [2].

The acetabulum is composed mainly of cancellous bone and impaction bone grafting has been a successful method of restoration of the acetabular deficiencies in revision hip arthroplasty [3-5].

The impaction bone grafting (IBG) technique was introduced for use in the acetabulum by Slooff et al. (6) and has proven to be effective in revision surgery. Different series have confirmed excellent results using this technique [7-10].

Cup migration and graft resorption are the main the main complications of this technique as reported by many authors [8-10].

The use of IBG technique for acetabular bone loss after failed management of acetabular fractures is challenging. We therefore evaluated patients undergoing acetabular revision surgery following acetabular fracture using IBG and a cemented cup in large bone defects to determine the ability to restore hip function and biomechanics, and also to report the incorporation of the graft.

Patients and Methods
Between January 1, 2011 and December 31, 2014, 43 patients underwent acetabular revision surgeries using IBG technique. The indication for surgery was acetabular deficiency secondary to failed acetabular fixation or failed conservative treatment of acetabular fractures. All patients were treated with a cemented dual mobility cup and impaction bone grafting which was protected by Kerboul ring. Two patients had died due to causes unrelated to the operation. The remaining 41 patients were available for follow up at a minimum of 3 years (mean: 4.1 years; range, 3-7).

All patients signed written informed consents. The study had been approved by our Menoufia university hospitals ethics committee and had therefore been performed in accordance with the ethical standards laid down in the 1964 Declaration of Helsinki.

Mean age was 69 years (± 1.1). There were 26 females and 15 males. The right hip was affected in 21 patients, while the left hip in 20. The diagnosis was failed acetabular fixation in 36 patients and osteoarthritis of the hip following conservative treatment of acetabular fracture in 5 patients. The average time between the initial fracture and the revision acetabular surgery was 38 months (range, 11-44) (table 1).

Pre-operative defects were classified according to the American Academy of Orthopedic Surgeons (AAOS) [11]. Type 2 cavitary defects were present in 38 patients and type 3 combined defects in three.

All surgeries were done using a postero-lateral approach. The pervious metallic hardware in the group with previous acetabular fixation was removed when they interfere with the operating field (29 cases). The acetabular margins were defined and bone defects were determined. The acetabular bed was reamed and prepared in a standard fashion. Fresh-frozen femoral heads allograft from the bone bank was used in 31 cases and the patient head of femur was used in the other 10 cases. Bone chips were morselized manually using a rongeur with a size of 0.7 to 1cm³ and impacted with acetabular reaming in a reverse direction. The acetabulum was cleaned and filled with bone graft to a thickness of at least 5mm. A dual mobility cup was cemented using antibiotic-loaded PMMA in all patients. kerboul ring was used to protect the graft. Cemented femoral prostheses were used in all cases.

All patients received prophylactic antibiotics (cefazolin) for 5 days. Indomethacin 25mg three times daily were given for 7 days to prevent heterotopic ossification. All patients received thrombosis prophylaxis with low-molecular-weight heparin for 35 days.

The postoperative rehabilitation protocol involved early mobilization using a walking frame and partial weight-bearing on the operated side for 3-6 weeks depending on the degree of the bone defect. After that, graduated return to full weight-bearing was allowed as tolerated. The patients used a crutch or a cane for at least 6 months after the operation.

Clinical evaluation of the patients was performed using Harris hip score [12] preoperatively and at 3 and 6 months post-operative, and then yearly afterwards. Standard AP and lateral radiographs of both hips and pelvis were made for all patients immediately after operation and at every follow up examination. Displacement of the acetabulum component was used to define a definitely loose cup. Impending failure was used to describe acetabular components showing a continuous radiolucent line greater than 2mm thick. The radiolucencies were assessed using the zonal analysis suggested by De Lee and Charnley [13]. The true acetabular position was defined using the method of Ranawat et al. [14]. Bone graft incorporation was also assessed by observing trabecular bridging and remodeling in serial follow-up radiographs. Radiographs were also reviewed for heterotopic ossification.

Results
The follow up period ranged from 3 to 7.6 years; with a mean of 4.1. At the latest follow up, the mean Harris hip score was 92.1 (range 61-95), with a mean improvement of 46.4 (range 37-62). Hip pain was relieved in all patients. Only six patients used analgesics (paracetamol 500mg) on long distance walking. Walking ability was improved in all patients. 33 patients were able to walk without aids; and 8 patients used a cane for outside walking. Leg length discrepancy was restored to less than one cm in all patients.

Radiologically, according to the criteria listed above, 39/41 patients had stable implants with no signs of loosening (Figure I). Possible acetabular loosening was found only in two patients; but no revision was required till the end of follow up. Bone graft was completely incorporated in the acetabulum in all cases. Two patients had Brooker type I heterotropic ossification. At an average 4.1 years follow up, there was 100% implant survivorship and no evident risk for revision (Figure 1).

Regarding complications, one patient had a partial sciatic nerve palsy which was completely recovered by 3 months and two patients had signs of early infection which resolved by early debridement and antibiotics and retention of the components.

Discussion
Acetabular fractures are common fractures especially in elderly patients. Open reduction and internal fixation is the most commonly used method for management of these fractures [15]. Failed management of these fractures leads to significant disabilities and mal-function. Hip arthroplasty after failure of acetabular fracture surgery is challenging, and many problems may be encountered including bone loss in the acetabulum, pelvis deformities, infections, osteonecrosis, heterotopic ossification, old implants, and sciatic nerve palsy [16-18]. The principles of acetabular reconstruction include the creation of a stable acetabular bed, secure prosthetic fixation, bony reconstitution, and the restoration of a normal hip center of rotation with acceptable biomechanics. The type and the extent of acetabular bone loss (segmental or cavitary) determines the method of reconstruction.

Ronmess and Lewallen [16] reported revision and loosening rates for the cemented cups used in posttraumatic hip arthritis after acetabular fractures that were four-fold higher than those in osteoarthritic patients; their data demonstrated a cup revision rate of 13.7% and a loosening rate of 49%, with 27% of those hips having symptomatic loosening

More recently, Hammad et al [17] assessed 32 patients undergoing THA after failed dynamic hip screw fixation and found only one periprosthetic fracture and one dislocation. Clinical outcomes were good-excellent in 78% of patients at the final follow-up.

On the other hand, Pereira et al. [19] reported excellent results with 100% survivorship of impaction bone grafting in a retrospective review of 23 primary THAs at a mean 7.9-year follow-up. Similarly, Patil et al. [20] noted a good clinical outcome and satisfactory consolidation of autografts used for the treatment of protrusio in 30 primary THAs at a mean 4.2-year follow-up. Our results are comparable to those in primary THAs.

The advantage of grafting is that it avoids the need to use mega cups, oblong cups, or metallic tantalum augments to fill bony voids and to decrease the size of the bony socket, allowing the use of cups the same size as the normal contralateral side, thereby restoring the hip center of rotation to its proper site, restoring the normal biomechanics of the hip and improving the durability of the acetabular construct.

Due to the previous procedures the possibility of infection and heterotrophic ossification is high. In spit of applying strict aseptic maneuvers in our series, and using indomethacin, we had 2 cases of early infection and one case of heterotrophic ossification. The limitations of this study are the relatively small number of cases, and mid-term follow up. Longer follow up is needed to assess the longevity of this technique.

Conclusion
In conclusion, results of this research suggest that the conversion of posttraumatic acetabular arthritis after acetabular internal fixation to THA is clinically successful without increased risk of complications, and is a safe option that provides good functional and radiological results.

Bibliography

1. Luca Pierannunzii & Luigi Zagra. (2016). Bone grafts, bone graft extenders, substitutes and enhancers for acetabular reconstruction in revision total hip arthroplasty. EFORT Open Rev., 1(12), 431-439.
2. Michael Whitehouse, R., Bassam Masri, A., Clive Duncan, P. & Donald S. (2015). Continued Good Results With Modular Trabecular Metal Augments for Acetabular Defects in Hip Arthroplasty at 7 to 11 Years. Garbuz Clin Orthop Relat Res., 473(2), 521-527.
3. Gie, G. A., Linder, L., Ling, R. S., et al. (1993). Impacted cancellous allografts and cement for revision total hip arthroplasty. J Bone Joint Surg [Br]., 75(1), 14-21.
4. Halliday, B. R., English, H. W., Timperley, A. J., Gie, G. A. & Ling, R. S. (2003). Femoral impaction grafting with cement in revision total hip replacement. Evolution of the technique and results. J Bone Joint Surg [Br]., 85(6), 809-817.
5. Ornstein, E., Linder, L., Ranstam, J., et al. (2009). Femoral impaction bone grafting with the Exeter stem - the Swedish experience: survivorship analysis of 1305 revisions performed between 1989 and 2002. J Bone Joint Surg [Br]., 91(4), 441-446.
6. Slooff, T. J., Buma, P., Schreurs, B. W., Schimmel, J. W., Huiskes, R. & Gardeniers, J. (1996). Acetabular and femoral reconstruction with impacted graft and cement. Clin Orthop Relat Res., (324), 108-115.
7. El-Kawy, S., Hay, D. & Drabu, K. (2005). Clinical and radiological bone allograft technique results of impaction in acetabular revisions associated with massive bone stock deficiencies: four to seven years follow-up study. Hip Int., 15(1), 46-51.
8. Schreurs, B. W., Bolder, S. B. T., Gardeniers, J. W. M., Verdonschot, N., Slooff, T. J. J. H. & Veth, R. P. H. (2004). Acetabular revision with impacted morsellised cancellous bone grafting and a cemented cup. A 10- to 20-year follow-up. J Bone Joint Surg Br., 86(4), 492-497.
9. Schreurs, B. W., Keurentjes, J. C., Gardeniers, J. W. M., Verdonschot, N., Slooff, T. J. J. H. & Veth, R. P. H. (2009). Acetabular revision with impacted morsellised cancellous bone grafting and a cemented acetabular component. A 20- to 25-year follow-up. J Bone Joint Surg Br., 91(9), 1148-1153.
10. Schreurs, B. W., Slooff, T. J. J. H., Buma, P., Gardeniers, J. W. M. & Huiskes, R. (1998). Acetabular reconstruction with impacted morselized cancellous bone graft and cement. A 10- to 15-year follow-up of 60 revision arthroplasties. J Bone Joint Surg Br., 80(3), 391-395.
11. D’Antonio, J. A., Capello, W. N., Borden, L. S., Bargar, W. L., Bierbaum, B. F., et al. (1989). Classification and management of acetabular abnormalities in total hip arthroplasty. Clin Orthop Relat Res., (243), 126-137.
12. Harris, W. H. (1969). Traumatic arthritis of the hip after dislocation and acetabular fracture: treatment by mold arthroplasty. J Bone Joint Surg., 51(4), 737-755.
13. DeLee, J. G. & Charnley, J. (1976). Radiological demarcation of cemented sockets in total hip replacement. Clin Orthop Relat Res., (121), 20-32.
14. Ranawat, C. S., Dorr, L. D. & Inglis, A. E. (1980). Total hip arthroplasty in protrusio acetabuli of rheumatoid arthritis. J Bone Joint Surg Am., 62(7), 1059-1065.
15. Ali, E. (2015). Acetabular Fractures - A Review of their Management. J Trauma Treat., 4, 278.
16. Romness, D. W. & Lewallen, D. G. (1990). Total hip arthroplasty after fracture of the acetabulum: long-term results. J Bone Joint Surg Br., 72(5), 761-764.
17. El-Khadrawe., T. A., Hammad, A. S., Hassaan, A. E., El-Khadrawe, T. A., Hammad, A. S. & Hassaan, A. E. (2012). Indicators of outcome after internal fixation of complex acetabular fractures. Alexandria Med J., 48(2), 99-107.
18. Schnaser, E., Scarcella, N. R. & Vallier, H. A. (2014). Acetabular fractures converted to total hip arthroplasties in the elderly: how does function compare to primary total hip arthroplasty? J Orthop Trauma., 28(12), 694-699.
19. Pereira, G. C. T., Kubiak, E. N., Levine, B., Chen, F. S. & Di Cesare, P. E. (2007). Cavitary acetabular defects treated with morselized cancellous bone graft and cementless cups. Int Orthop., 31(4), 445-450.
20. Patil, N., Hwang, K. & Goodman, S. B. (2012). Cancellous impaction bone grafting of acetabular defects in complex primary and revision total hip arthroplasty. Orthopedics, 35(3), e306-312.