Impaction grafted bone chip size effect on initial stability in an acetabular model: Mechanical evaluation

Impaction bone grafting for contained acetabular defects in total hip arthroplasty

BACKGROUND

Acetabular bone loss is a technical challenge in total hip arthroplasty (THA). This study sought to report the functional and radiological results of acetabular reconstruction using impaction bone grafting (IBG) in patients with acetabular bone deficiency undergoing primary or revision THA.

METHODS

In this prospective study, full history taking, preoperative clinical and radiological evaluation, and preoperative planning and templating were performed. The Paprosky classification and the American Academy of Orthopaedic Surgeons classification were used to assess the acetabular deficiencies. Clinical outcomes were assessed utilizing the Harris hip score (HHS) and a 4-question satisfaction questionnaire. Graft incorporation was evaluated in the last follow-up X-rays.

RESULTS

This study included 50 patients with a mean age of 46.7 ± 15.3 years. The THA was primary in 14 (28%) patients and revision in 36 (72%) patients. The mean HHS improved significantly from 28.8 ± 24.1 preoperatively to 76.6 ± 6.1, with a mean follow-up period of 23 months. Overall, 88% of patients were very satisfied. Complete radiological graft incorporation to host bone was achieved in 35 (70%) patients, and the remaining patients had partial incorporation. Complete graft incorporation was associated more frequently with primary THA, autografts, cementless cups, decreased defect size, and decreased graft layer thickness.

CONCLUSIONS

IBG for acetabular reconstruction in THA can achieve excellent clinical and radiological outcomes with a low complication rate.

LEVEL OF EVIDENCE

Level IV.

Surgical management of hip prosthetic failure in metallosis: A case series and literature review

Local and remote complications can be observed in hip prosthesis failures associated with metallosis. Structural changes in the periprosthetic bone and soft tissues may not always be precisely assessed preoperatively due to metal artifacts. The unpredictability of the damage extension, potentially leading to complex and insidious surgeries, requires the availability of alternative surgical plan(s) for the reconstruction of the joint. The aim of the study is to present and analyze, with the literature data support, practical tips for the revision of the prosthetic components, the management of ARMD and of intraoperative complications in the unusual scenario of metallosis.

Determination of structural femoral head allograft viability and integrity with a novel diagnostic tool: SPECT/CT. A preliminary study

OBJECTIVE

To evaluate the viability and integrity of fresh frozen bulk femoral head allografts obtained from the institutional bone bank that were used to reconstruct severe acetabular defects and to validate the SPECT/CT method which gives both anatomical and functional data for this purpose.

METHODS

We retrospectively reviewed 9 patients (6 female, 3 male; mean age 63.6 years). Preoperative and postoperative leg lengths, existence of the Trendelenburg sign, range of motion of the hip, visual analogue score (VAS), Harris Hip Score (HHS) and any complication were assesed at each follow-up. Radiographically, position of the cup, signs of loosening or migration, and union of the graft were all determined. At the latest follow-up, patients were evaluated with hybrid SPECT/CT.

RESULTS

The average duration of follow-up was 38.1 months (24-50 months). The overall mean HHS and VAS scores were significantly improved (p<0.05). When hybrid SPECT/CT results were evaluated, the vascular phase of scintigraphy showed hyperaemia of the graft and the bone phase of scintigraphy showed normal or increased radiotracer uptake in the graft site in 7 patients. SPECT/CT images were used to determine the exact localisation of osteoblastic activity. 1 patient with minor resorption of the graft without clinical symptoms revealed mild osteoblastic activity. The patient who had no activity in the graft site was rerevised because of infection.

CONCLUSIONS

Institutional bank allografts are still excellent options for treating large acetabular defects in revision total hip arthroplasty where trabecular metals are not available or in common use. The Hybrid SPECT/CT method is a reliable, noninvasive method for evaluating both the integrity and viability of a bulk graft in 3-D.

Reconstruction of non-contained acetabular defects with impaction grafting, a reinforcement mesh and a cemented polyethylene acetabular component

This review summarises the technique of impaction grafting with mesh augmentation for the treatment of uncontained acetabular defects in revision hip arthroplasty.

The ideal acetabular revision should restore bone stock, use a small socket in the near-anatomic position, and provide durable fixation. Impaction bone grafting, which has been in use for over 40 years, offers the ability to achieve these goals in uncontained defects. The precepts of modern, revision impaction grafting are that the segmental or cavitary defects must be supported with a mesh; the contained cavity is filled with vigorously impacted morselised fresh-frozen allograft; and finally, acrylic cement is used to stabilise the graft and provide rigid, long-lasting fixation of the revised acetabular component.

Favourable results have been published with this technique. While having its limitations, it is a viable option to address large acetabular defects in revision arthroplasty.

Cite this article: Bone Joint J 2017;99-B(1 Supple A):25–30.

Effect of thermodisinfection on mechanic parameters of cancellous bone

Revision surgery of joint replacements is increasing and raises the demand for allograft bone since restoration of bone stock is crucial for longevity of implants. Proceedings of bone grafts influence the biological and mechanic properties differently. This study examines the effect of thermodisinfection on mechanic properties of cancellous bone. Bone cylinders from both femoral heads with length 45 mm were taken from twenty-three 6-8 months-old piglets, thermodisinfected at 82.5 °C according to bone bank guidelines and control remained native. The specimens were stored at -20 °C immediately and were put into 21 °C Ringer's solution for 3 h before testing. Shear and pressure modulus were tested since three point bending force was examined until destruction. Statistical analysis was done with non-parametric Wilcoxon, t test and SPSS since p < 0.05 was significant. Shear modulus was significantly reduced by thermodisinfection to 1.02 ± 0.31 GPa from 1.28 ± 0.68 GPa for unprocessed cancellous bone (p = 0.029) since thermodisinfection reduced pressure modulus not significantly from 6.30 ± 4.72 GPa for native specimens to 4.97 ± 2.23 GPa and maximum bending force was 270.03 ± 116.68 N for native and 228.80 ± 70.49 N for thermodisinfected cancellous bone. Shear and pressure modulus were reduced by thermodisinfection around 20 % and maximum bending force was impaired by about 15 % compared with native cancellous bone since only the reduction of shear modulus reached significance. The results suggest that thermodisinfection similarly affects different mechanic properties of cancellous bone and the reduction of mechanic properties should not relevantly impair clinical use of thermodisinfected cancellous bone.

Increased risk for extended acetabular reconstruction in failed hip resurfacing as compared to failed total hip arthroplasty

INTRODUCTION

Hip resurfacing (HR) is intended to preserve the femoral bone stock during primary arthroplasty. On the other hand, little has been reported regarding the intraoperative need of bone reconstruction for extended acetabular defects during hip resurfacing revision. Thus, the aim of the presented study was to identify whether there is an increased need for acetabular bone reconstruction in HR revision surgery.

MATERIALS AND METHODS

We analyzed the data of 38 patients who underwent 39 conversions from a HR to a total hip arthroplasty (THA). Acetabular bone defects and the respective revision technique were compared against a temporary cohort of patients undergoing revision surgery of a conventional THA.

RESULTS

In 29 HR patients revision required either autogenous or allogenous impaction bone grafting to adequately manage acetabular host bone degradation. In 10 cases additional implantation of a reinforcement device was necessary. Compared to the THA cohort revision of failed HR is associated with a significantly increased risk of higher grade bone defects (Paprosky classification) and extended acetabular reconstruction (p < 0.05).

CONCLUSIONS

This study provides evidence that revision of failed HR devices is associated with an increased risk for extensive acetabular defects. Furthermore, the preoperative radiographic assessment of HR devices often underestimates the intraoperative acetabular defect. Surgeons should be aware of this fact not to technically underestimate HR revision procedures.

Antibiotics in frozen bone grafts can cause allergic reactions in recipient patients

Antibiotic prophylaxis is a routine procedure during total hip arthroplasty (THA), and the vast majority of cadavers within the multitissue procurement receive one or more antibiotics. Upon harvesting, bone grafts are stored in the bone banks on the temperature as low as -80°C for up to 5 years. It is shown in the literature that the antibiotics remain active and viable in the bone grafts even after being exposed to extremely low temperatures in the prolonged periods. Possibility of remnant antibiotic concentrations in the bone grafts and the fact that these antibiotic remnants maintain active even after being exposed to extremely low temperatures create the environment in which the possibility for the allergic reaction in sensitive patient receiving bone graft exists. We hypothesize that harvested bone grafts containing active antibiotic substance have the potential for local and systemic allergic reaction in sensitive recipient patients thus increasing morbidity and the costs of the treatment. Allergic reactions can mimic surgical site infections as well with the consequent substantial pitfalls in the treatment. Following that, in the setting of an assumed but not confirmed surgical site infection, the immunological evaluation on antibiotics for recipients of bone grafts could be added to the standard diagnostic algorithms. In addition, bone banks should be obliged to provide information of all potential drugs that can be found in every specific bone graft to the end users.