Biologic Treatment Options for the Hip: A Narrative Review

H. Thomas Temple, MD

Disclosures

Curr Orthop Pract. 2019;30(6):501-509. 

In This Article

Pelvic Osteoarticular Allografts

Large pelvic allografts are used after pelvic resections that involve all or a large portion of the acetabulum (type II resections).[5] Candidly, outcomes, both oncologic and functional are guarded after resection and allograft reconstruction especially for patients with large and high-grade tumors.[6] In fact patients with pelvic allografts have worse outcomes compared to other patients with femoral allografts with similar diagnoses. Allografts used for reconstruction should be processed aseptically by a tissue bank that preferably is accredited by the American Association of Tissue Banks. Because of the relationship of bowel to the pelvis, post-mortem bacterial contamination is frequent. For this reason, other steps that may or may not affect graft incorporation are taken, specifically, decontamination steps using proprietary solutions containing detergents, peroxide and alcohol, and/or gamma irradiation. Preoperative planning is critical to achieve the closest fit possible. Although intuitively obvious, unlike other transplantable bones in the body, pelvic allograft matching is gender-specific as the morphology of the male and female pelvis is substantially different. Soft-tissue attachments, especially the hip capsule, are very useful in achieving early hip stability as well as maintaining abductor attachments and tension.

There are many complications associated with resection and allograft reconstruction of the pelvis. The major complications that are associated with pelvic allograft reconstruction include: nonunion, fracture, hip dislocation, aseptic loosening, and infection.[7] There are many other potential risks associated with the resection as well. One study comparing various reconstructive techniques after tumor resection reported a risk of infection of 23.6% but showed no statistical difference between allograft reconstruction and other types of reconstruction.[8–12] This suggests that extensive dissection, patient comorbidities, the use of preoperative adjuvants, operative time, and blood loss may play a prominent role in postoperative infections in these patients independent of the allograft and subsequent reconstruction itself.

Despite the considerable time, effort, and potential complications, results can be successful in many patients. In a retrospective study, Donati et al.[13] reviewed 35 patients who underwent resection of the entire acetabulum and subsequent reconstruction with an allograft-prosthetic composite. Follow-up in 24 survivors averaged 120 mo. They found that 75% of the allografts were still in place at last follow-up, and the original prosthetic reconstruction was still intact in 56%. The average MSTS score was 72%.[13] An example of a durable allograft is illustrated in the following case:

A 35-year-old woman presented with right hip pain. She had previously undergone a type II resection of the pelvis 13 yr previously followed by reconstruction using an osteoarticular allograft for a giant cell tumor of bone with extensive periacetabular bone destruction. She presented 13 yr later with right hip pain. Her radiographs demonstrated obvious degenerative changes of the hip; however, the allograft was healed and appeared to be incorporated (Figure 2A). At the time of surgery to replace her hip, upon reaming the acetabulum, there was bleeding in the cancellous bone. She was subsequently treated with an uncemented acetabular cup and cemented stem. Two years later, at last follow-up, she had normal function and no pain. Interestingly, curettings of the residual acetabular cartilage were obtained and examined histologically. For the most part, fibrocartilage was observed but in other areas, small islands of chondrocytes were seen in a hyaline matrix to suggest that these cells survived freezing and thawing and persisted for many years (Figure 2B and C).

Figure 2.

A, Anteroposterior pelvic radiograph of a 34-year-old woman who underwent a type II resection of the pelvis and an osteoarticular pelvic allograft reconstruction 12 yr ago. The graft is healed, and it is difficult to see the junction sites. There are advanced arthritic changes in the hip with joint space narrowing and osteophyte formation. B, This slide demonstrates the predominate histopathologic (200x H&E) fibrocartilage. C, Although fibrocartilage was predominate, there were small areas of hyaline cartilage with nests of chondrocytes in this cryopreserved allograft 12 yr after implantation (400x H&E).

Other biologic alternatives include the use of autografts that are either autoclaved[14,15] or irradiated.[16] Harrington[15] reviewed a subset of patients in a series of 14 patients who underwent resection and subsequent reconstruction with the resected pelvis that was subsequently autoclaved. Although good results were reported in 12 patients at 2-year follow-up, later, three grafts failed due to fracture; many other complications were observed.[15] The use of extracorporeal radiation or autoclaving requires minimal structural compromise of the affected bone and requires augmentation with PMMA. Fracture therefore is the likeliest complication in the intermediate and long-term follow-up of these grafts. Freezing, using either a pedicle or free-graft technique has been described. Subhadrabandhu et al.[17] described 22 patients treated by this technique. Only one hemipelvis was included in the series. They reported "excellent" MSTS functional results. Complications included: fracture (one), infection (two), soft-tissue recurrence (three) and nerve injury (one). Most concerning perhaps are the soft-tissue recurrences and the question being whether or not liquid nitrogen freezing and thawing is sufficient to cause adequate tumor cell death.

Recent advances in navigation[18,19] and 3-D printing[20] may improve outcomes in pelvic resection and reconstruction, respectively. CT can be used to create 3-D prototypes of the pelvic bone tumor (Onkos Surgical, Persippany, NJ) from which printed cutting guides can be created. The 3-D models are then used to plan the resection as well as to select an appropriate allograft. The guides are used to accurately cut the patient's pelvis in three dimensions. Similar guides are placed on the pelvic allograft that is cut on the back table (Figure 3A and B). The obvious advantage is a near-perfect match between the defect and the allograft, with restoration of the osseous anatomy (Figure 3C and D). In addition, there is considerable time saved by not having to cut the pelvic allograft free hand to create the best match by trial and error.

Figure 3.

A and B, This is an osteoarticular allograft with cutting guides placed on the surface of the allograft to precisely cut the graft to fit into the defect after resection. These guides were three-dimensionally (3-D) printed and based on a 3-D model of the patient pelvis and tumor reconstructed from a CT scan. The surgeon works with the engineers to select the appropriate cut maintaining an adequate tumor margin.

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