Morselized Cancellous Bone Research Articles

Reconstruction of Acetabular Defects With Impaction Grafting in Primary Cemented Total Hip Arthroplasty Produces Favorable Results: Clinical and Radiographic Outcomes Over 6.4 Years on Average

BackgroundCemented primary total hip arthroplasty (THA) associated with acetabular reconstruction (AR) involving impacted bone grafting has been employed successfully in the revision of cavitary defects but the results are reportedly less predictable for segmental defects. The objective of the study is to evaluate the clinical and radiographic results of patients who had presented cavitary, segmental, and combined acetabular defects and received THA/AR involving impacted morselized cancellous bone autografts followed by rigorous postoperative management. MethodsClinical outcomes were assessed retrospectively of 154 patients who had been submitted to 169 THA/AR procedures performed by a single surgeon over a 15-year period. The Harris Hip Score system was applied to 103 patients, and the degree of acetabular migration was determined from radiograph images of 91 AR procedures, of which 40 were segmental/combined and 51 were cavitary reconstructions. ResultsThe frequency of aseptic acetabular loosening was 3% while that of thromboembolic events was 4.1%. According to Harris Hip Score, 87.4% of outcomes were classified as excellent/good after an average follow-up period of 6.4 years irrespective of the type of acetabular defect. Horizontal and/or vertical acetabular migrations and changes in angular tilt were observed in all ARs, although the minor movements detected did not undermine the structural stability of the reconstructions or the functional capacity of patients. ConclusionThe described THA/AR technique can be used effectively in the reconstruction of segmental/combined and cavitary acetabular defects. The success of the technique as applied to segmental/combined defects was attributed in part to the rigorous rehabilitation protocol with temporary postoperative weight-bearing restriction.

Patient-Specific 3-Dimensional Printing Titanium Implant Biomechanical Evaluation for Complex Distal Femoral Open Fracture Reconstruction with Segmental Large Bone Defect: A Nonlinear Finite Element Analysis

This study proposes a novel titanium 3D printing patient-specific implant: a lightweight structure with enough biomechanical strength for a distal femur fracture with segmental large defect using nonlinear finite element (FE) analysis. CT scanning images were processed to identify the size and shape of a large bone defect in the right distal femur of a young patient. A novel titanium implant was designed with a proximal cylinder tube for increasing mechanical stability, proximal/distal shells for increasing bone ingrowth contact areas, and lattice mesh at the outer surface to provide space for morselized cancellous bone grafting. The implant was fixed by transverse screws at the proximal/distal host bone. A pre-contoured locking plate was applied at the lateral site to secure the whole construct. A FE model with nonlinear contact element implant-bone interfaces was constructed to perform simulations for three clinical stages under single leg standing load conditions. The three stages were the initial postoperative period, fracture healing, and post fracture healing and locking plate removal. The results showed that the maximum implant von Mises stress reached 1318 MPa at the sharp angles of the outer mesh structure, exceeding the titanium destruction value (1000 MPa) and requiring round mesh angles to decrease the stress in the initial postoperative period. Bone stress values were found decreasing all the way from the postoperative period to fracture healing and locking plate removal. The overall construct deformation value reached 4.8 mm in the postoperative period, 2.5 mm with fracture healing assisted by the locking plate, and 2.1 mm after locking plate removal. The strain value at the proximal/distal implant-bone interfaces were valuable in inducing bone grafting in the initial postoperative period. The proposed patient-specific 3D printed implant is biomechanically stable for treating distal femoral fractures with large defect. It provides excellent lightweight structure, proximal/distal bone ingrowth contact areas, and implant rounded outer lattice mesh for morselized cancellous bone grafting.

The use of hardened bone cement as an impaction grafting extender for revision hip arthroplasty.

Impaction bone grafting is a method of restoring bone stock to patients who have suffered significant bone loss due to revision total hip surgery. The procedure requires morsellised cancellous bone (MCB) to be impacted into the site of bone loss in order to stabilise the prosthesis with the aim of long term resorption and reintegration of the impacted bone graft. Due to financial cost and the potential to transmit disease, the use of supplementary material, known as an extender, is frequently used to increase the graft material volume. This study investigates the use of hardened Hydroset (Stryker Corp, MA, USA), an injectable bone cement (IBC), as an extender material and compares the performance of the IBC in different weight percent inclusions to a commercially available bone graft extender (GCP, BoneSave, Stryker Corp, MA, USA). The surgical impaction procedure was standardised and samples were evaluated in terms of graft stiffness and height. It was observed that 30wt% IBC extended samples had significantly improved graft stiffness (p = 0.02) and no significant different in height (p = 0.067) over a 100% MCB control sample. Cyclic loading, representative of gait, found that the IBC subsided similarly to the commercial bone substitute in wt% above 10%. Shear testing of the impacted grafts showed no significant differences between GCP and IBC with impaction forces determining the shear parameters of impacted grafts. The effects of the impaction and cyclical loading procedures on extender particle sizes was assessed via particle size analysis. It was found that the IBC extended samples demonstrated reduced friability, evident in the better retention of particle size as a result of both impaction and gait representative loading compared to that of the GCP samples. This indicates a potential reduction in issues arising from small particle migration to joint surfaces. Scanning electron microscopy of the MCB particles with both GCP and IBC as extenders showed retention of the porous trabecular structure post-testing which is essential for revascularisation and bone growth into the graft.

Femoral impaction allografting for significant bone loss in revision hip arthroplasty.

Femoral impaction bone allografting in revision hip arthroplasty facilitates physiological reconstruction with restoration of bone stock, allowing implantation of a standard cemented femoral component. The purpose of this study was to report our experience in femoral component revision arthroplasty with impaction morsellised cancellous bone allograft using custom impactors and a cemented triple-taper polished stem. Retrospective analysis of all cases of femoral component revision hip arthroplasty with impaction bone grafting undertaken by a single surgeon from 2005 to 2011. Outcome measures included radiographic analysis of stem subsidence over time, graft remodelling and incorporation, and clinical progress. We reviewed 47 consecutive hips in 44 patients, mean age 62 years (37-88). Femoral impaction with allograft was performed as either single stage (41 cases) or 2-stage (6 cases) procedures. All patients received a cemented C-stem prosthesis. The mean follow-up period was 5.1 (1.3-9.4) years. The median preoperative bone defect score was 3 (interquartile range [IQR] 2-3) using the Endo-Klinik classification. Radiological evidence of graft incorporation was observed in 89% (281 of 315 zones) with additional remodelling observed in 33% (103 of 315 zones). The median stem subsidence at 1-year follow-up was 1.1 mm (standard deviation [SD] 1.24 mm, range 0-6 mm). The median Oxford Hip Score at the most recent follow-up was 36.5. To date no femoral component has undergone further revision. Encouraging results have been obtained with this technique for the treatment of significant bone loss in revision hip arthroplasty, allowing implantation of a standard prosthesis.

Morsellised sawbones is an acceptable experimental substitute for the in vitro elastic and viscoelastic mechanical characterisation of morsellised cancellous bone undergoing impaction grafting

Impaction grafting using morsellised bone chips is widely used during surgery to mitigate the effects of bone loss. The technique typically involves the packing of morsellised allograft cancellous bone into bone defects, and has found extensive application in revision hip and knee surgery. In the ideal situation, the presence of the bone graft prevents subsidence of the revised prosthesis in the short term, and integrates with the host bone in the longer term. However, the configuration of particles within the graft remains to be optimised, and is highly likely to vary across potential sites and loading conditions. Human bone, for use in experimental investigation, is often difficult to obtain with properties that are relevant from a clinical point of view. This study, therefore, has explored the mechanical response of a Sawbones based experimental substitute. An established confined compression technique was used to characterise the morsellised Sawbones material. Comparison of the results with published values for bovine and human bone indicate that the mechanical response of the morsellised Sawbones material map well onto the elastic and viscoelastic response of bone of a biological origin.

Biomechanical Analysis of Acetabular Defects Reconstruction with Impaction Bone Grafting in Revision Total Hip Arthroplasty

An objective of this study is to investigate the influence of an amount of mixture of hydroxyapatite (HA) granules and morsellised cancellous bone (MCB) on the initial stability of reconstructed acetabulum through mechanical testing. Reconstruction was carried out using impaction bone grafting technique with four mixture ratio, then, cyclically loaded as a simulation of the motion of gait and analyzed the migration. The initial stability is highly dependent on mixture ratio and larger HA mixture ratio could give us better initial stability of the cup.

Acetabular revision with impacted morsellised cancellous bone grafting and a cemented acetabular component

We present an update of the clinical and radiological results of 62 consecutive acetabular revisions using impacted morsellised cancellous bone grafts and a cemented acetabular component in 58 patients, at a mean follow-up of 22.2 years (20 to 25). The Kaplan-Meier survivorship for the acetabular component with revision for any reason as the endpoint was 75% at 20 years (95% confidence interval (CI) 62 to 88) when 16 hips were at risk. Excluding two revisions for septic loosening at three and six years, the survivorship at 20 years was 79% (95% CI 67 to 93). With further exclusions of one revision of a well-fixed acetabular component after 12 years during a femoral revision and two after 17 years for wear of the acetabular component, the survivorship for aseptic loosening was 87% at 20 years (95% CI 76 to 97). At the final review 14 of the 16 surviving hips had radiographs available. There was one additional case of radiological loosening and four acetabular reconstructions showed progressive radiolucent lines in one or two zones. Acetabular revision using impacted large morsellised bone chips (0.5 cm to 1 cm in diameter) and a cemented acetabular component remains a reliable technique for reconstruction, even when assessed at more than 20 years after surgery.

Impaction Grafting for Femoral Component Revision in a Goat Model Using Washed Morselized Cancellous Allograft

To determine whether washing morselized cancellous bone allograft in impaction grafting for revision hip arthroplasty would improve mechanical and biologic performance, left hip hemiarthroplasty with a collarless stem cemented into impacted morselized cancellous bone was performed in 22 goats. Washed allograft was used in the experimental group, and standard allograft was used in the control group. One of 11 experimental and 4 of 11 control implants were observed to be loose at 8 weeks. Washing allowed significantly more morselized cancellous bone to be placed in the experimental group compared to the control group (7.7±1.9 and 6.2±2.0 g, respectively, P <.05). Significantly less in vivo subsidence over the 8-week study period also was demonstrated in the experimental group compared to the control group (0.4±0.4 and 2.2±2.3 mm, respectively, P <.05). Angular motion during cyclic ±1.5 Nm loading demonstrated significant differences between the 2 groups at time zero (2.67°±1.02° for the control group and 1.98°±0.47° for the experimental group, P <.05) and at 8 weeks (2.40°±0.38° for the control group and 1.74°±0.55° for the experimental group, P <.05). Histology showed little difference between the 2 groups, but there was a trend toward less inflammation in the experimental group.

Impaction Grafting for Femoral Component Revision in a Goat Model Using Washed Morselized Cancellous Allograft

To determine whether washing morselized cancellous bone allograft in impaction grafting for revision hip arthroplasty would improve mechanical and biologic performance, left hip hemiarthroplasty with a collarless stem cemented into impacted morselized cancellous bone was performed in 22 goats. Washed allograft was used in the experimental group, and standard allograft was used in the control group. One of 11 experimental and 4 of 11 control implants were observed to be loose at 8 weeks. Washing allowed significantly more morselized cancellous bone to be placed in the experimental group compared to the control group (7.7+/-1.9 and 6.2+/-2.0 g, respectively, P<.05). Significantly less in vivo subsidence over the 8-week study period also was demonstrated in the experimental group compared to the control group (0.4+/-0.4 and 2.2+/-2.3 mm, respectively, P<.05). Angular motion during cyclic +/-1.5 Nm loading demonstrated significant differences between the 2 groups at time zero (2.67 degrees +/-1.02 degrees for the control group and 1.98 degrees +/-0.47 degrees for the experimental group, P<.05) and at 8 weeks (2.40 degrees +/-0.38 degrees for the control group and 1.74 degrees +/-0.55 degrees for the experimental group, P<.05). Histology showed little difference between the 2 groups, but there was a trend toward less inflammation in the experimental group.

Histologic Analysis of Allograft Mixed With Hydroxyapatite-Tricalcium Phosphate Used in Revision Femoral Impaction Bone Grafting

Failed total hip arthroplasty (THA) often is accompanied by loss of bone stock. In cases in which revision THA becomes necessary, adequate stabilization of the implant can be difficult because of the bone loss. Bone can be reconstructed by using tightly packed morselized cancellous bone graft in combination with a cemented stem. However, worldwide availability of human bone is limited, and risks such as infection and antigenicity are associated with the use of allogeneic bone. These risks have led to the development of synthetic bone graft extenders. The objective of impaction bone grafting is to achieve stability of an implant and subsequently allow the restoration of living bone stock. To reduce the amount of allograft consumed, a mixture of morselized allograft and hydroxyapatite-tricalcium phosphate was used for impaction grafting in a series of 15 patients. In 2 patients who required re-revision arthroplasty, the areas of impacted graft were analyzed histologically. The results showed a complex mixture of residual hydroxyapatite-tricalcium phosphate, necrotic bone (graft), viable bone, and fibrous tissue. Although several pre-clinical studies have described the expansion of allograft with synthetic materials, this article represents the first description of histologic findings in human femoral impaction grafting with a combination of allograft and hydroxyapatite-tricalcium phosphate.

Stability Differentials for Proximal vs Distal Fusion of Total Hip Arthroplasty Femoral Impaction Grafts

In impaction grafting for revision joint arthroplasty, the morselized cancellous bone ideally remodels into a new contiguous lattice. However, the use of biologically active factors may sometimes be indicated to enhance fusion. The purpose of this study was to determine the stability of femoral impaction-graft constructs for which either only the proximal or distal half of the morselized cancellous bone volume was modeled as fused. Fusing the proximal half of the impaction-graft volume resulted in a higher femoral stem stability than did fusing the distal half. This proximal graft fusion also resulted in a stem stability that was similar to that of fusing the entire graft. These results emphasize the importance of proximal fixation of an impaction-grafted femoral stem.

Stability of fused versus nonfused THA femoral impaction grafts.

Impaction grafting for THA involves compacting morselized cancellous bone (MCB) into a cavitary defect to build up bone stock. Ideally, the MCB subsequently remodels into a new contiguous cancellous lattice. A recent laboratory model of MCB fusion allows simulating an impaction graft construct in this ideal eventual clinical state. The purpose of the present study was to determine the relative stability of femoral impaction graft constructs in which the MCB has fused versus that for MCB in the freshly impacted nonfused condition. Cemented femoral impaction graft constructs were created in composite femurs. For fused constructs, the MCB was mixed with an amine epoxy that causes the MCB to set up into a contiguous structure biomechanically comparable to intact cancellous bone in compression. The constructs were loaded with 500,000 physiologic gait cycles. Three-dimensional motion was measured between the femur and the stem. The fused femoral impaction grafts were much more stable than the nonfused grafts at the proximal stem location, but MCB fusion had only a modest effect on distal stem stability. These results indicate that most of the opportunity to reduce femoral stem micromotion and migration lies proximal, and that steps to enhance impaction graft remodeling and fusion are most effectively focused proximally.

Cavitary acetabular defects treated with morselized cancellous bone graft and cementless cups

The use of impacted morselized cancellous bone grafts in conjunction with cementless hemispherical acetabular cups for treatment of AAOS type II acetabular cavitary deficiencies was evaluated in a retrospective study of 23 primary and 24 revision total hip arthroplasties, at a mean follow-up of 7.9 and 8.1 years, respectively. All primary hips received autografts, while all revision hips received allografts. Modified Harris Hip Scores for primary and revision hip replacements increased from a pre-operative mean of 37 and 47 to a postoperative mean of 90 and 86, respectively. All 23 autografts and 23 out of 24 cancellous allografts were radiographically incorporated without evidence of resorption. There were no instances of infection, component migration, or cases requiring subsequent acetabular revision. We conclude that impacted morselized cancellous bone-graft augmentation of cementless cups is a viable surgical option for AAOS type II cavitary acetabular defects.

Cells seeded on MBG scaffold survive impaction grafting technique: Potential application of cell‐seeded biomaterials for revision arthroplasty

The objective of this study was to investigate the potential application of cell-seeded biomaterials for revision arthroplasty and the reconstruction of major joints using the impaction grafting technique. Using morselized cancellous bone graft as a porous scaffold, MG63 cells were seeded on the scaffold and impacted into an acetabulum cup model using a mechanical device constructed from data obtained during impaction grafting by an orthopedic surgeon. Immediately after impaction, cells were trypsinized from the scaffold and processed for cell survival rates using the double-stranded DNA PicoGreen assay. Significant reductions in viable cells were observed between the fifth impact and both the first and second impacts (p < 0.01 and p < 0.05, respectively). Cell survival rate was 21.5% after five impacts. The biological performance of cell-seeded biomaterials may be enhanced by these surviving cells. Compared to allograft bone that is not osteogenic, a cell-seeded biomaterial might also be a suitable substitute for allograft bone for major joint reconstruction at revision arthroplasty.

No Negative Effects of Bone Impaction Grafting with Bone and Ceramic Mixtures

Reconstructing large loaded bone defects with ceramic bone graft extenders is tempting considering the expected future donor bone shortage. However, whether there are negative effects is unknown. Standardized large defects in the acetabulum of goats were created and subsequently reconstructed with metal mesh and impacted morselized cancellous bone grafts or a 50/50% volume mixture of tricalcium phosphate-hydroxyapatite granules and morselized cancellous bone grafts using the bone impaction grafting technique. Subsequently, a cemented total hip prosthesis was inserted. Clinically, no differences were observed between groups. Most of the morselized cancellous bone graft had been resorbed and incorporated into new bone after 15 weeks. The large tricalcium phosphate-hydroxyapatite granules were integrated, the smaller crushed tricalcium phosphate-hydroxyapatite granules were surrounded by osteoclasts or engulfed by macrophages and giant cells. The cement penetration into the reconstructive layer and the quality of the bone based on a semiquantitative score were similar in both groups. We found no suggestion of tricalcium-hydroxyapatite granule-induced third-body wear in this short-term followup study. No negative effects were observed in this study, and therefore, it seems reasonable to use tricalcium-hydroxyapatite granules in a 50/50% volume mix with morselized cancellous bone graft as a bone graft extender in acetabular revision surgery with the bone impaction grafting technique.

TCP-HA Granules and Impacted Morselized Cancellous Bone Graft Mixes for Acetabular Reconstruction with the Bone Impaction Grafting Technique. A Loaded and Critical Sized Defect Model in the Goat

With the bone impaction grafting technique, a 50/50 volume mix of morselized cancellous bone (MCB) with TCP-HA granules was used to reconstruct a critical sized acetabular defect in the goat. The biological activity of the MCB/TCP-HA mix was assessed after 15 weeks. Defects filled with 100% MCB, currently the gold standard for this technique, were used as controls. In the 100% MCB defects, a new trabecular bone structure was found in which scarce incorporated remnants of the original graft material were present. In the MCB/TCP-HA defects, MCB was also resorbed or incorporated into new bone. Deep in the MCB-TCP-HA defects, large TCP-HA granules were generally totally osseous-integrated with new bone. Superficially, more fragmented TCP-HA granules of various sizes were present in the medullar tissue or in the interface with the cement layer. Here, the crushed TCP-HA granules were generally surrounded by osteoclasts and giant cells. The soft tissue interface between the reconstruction and cement did not differ between both groups. In conclusion, from a biological point of view, this short-term follow-up study suggests that TCP-HA granules can be safely used in a mix with MCB as bone graft extender in acetabular revision surgery with the bone impaction grafting technique.

Cemented Cup Stability during Lever-Out Testing after Acetabular Bone Impaction Grafting with Bone Graft Substitutes Mixes Containing Morselized Cancellous Bone and Tricalcium Phosphate-Hydroxyapatite Granules

Bone defects after failed total hip arthroplasty can be reconstructed with impacted morselized bone grafts and a cemented cup. In the near future the amount of bone grafts available for surgical purposes will be insufficient. Ceramic calcium phosphates [tricalcium phosphate (TCP) and hydroxyapatite (HA)] have been widely considered as potential bone graft substitutes or bone graft extenders. In the past, mechanical experiments have been performed to determine implant stability of bone grafts and ceramic TCP-HA granules mixes under a compressive load. However, in-vivo migration studies suggest that shear loading may be equally important. This in-vitro study investigated the initial stability of cups reconstructed with various mixes of bone grafts and ceramic TCP-HA granules in a lever-out situation, where shearing is the predominant loading mode. It was found that the cups reconstructed with mixes of bone graft and TCP-HA granules exhibited greater mechanical stability than the cups reconstructed with bone grafts only. It is concluded that from a mechanical standpoint, when considering shear force resistance, 50-50 per cent volume mix and 25-75 per cent volume mix of morselized cancellous bone graft and TCP-HA granules both provide adequate initial cup stability and can be used for acetabular reconstructions with the bone impaction grafting technique.

A laboratory simulation for morselized bone graft fusion: apparent modulus under operatively based femoral impaction kinetics

The purpose of this study was to determine the apparent modulus changes accompanying a novel procedure for simulating in situ fusion of morselized cancellous bone femoral impaction grafts. An experienced surgeon's habitual intra-operative impaction grafting protocol was first quantified in human cadaver femurs, using a customized impulse force hammer. A corresponding standardized impaction procedure was then defined, and was used to prepare impaction grafts in axisymmetric metallic fixturing designed to replicate the nominal geometry of femoral canal confinement. Impaction graft fusion was simulated by mixing morselized cancellous bone with an amine-based epoxy adhesive before the impaction, then allowing the mixture to fuse after the impaction (J. Biomech. 34 (2001) 811). Force/deflection behavior of the unfused and fused impaction grafts was measured for both the (tapered) proximal and (untapered) distal portions of the grafts. Apparent modulus was then calculated from force/deflection stiffness. The impaction graft fusion simulation increased apparent modulus by an order of magnitude over the unfused state, for mixture parameters appropriate to have the fused graft apparent modulus be comparable to the compressive modulus of intact femoral cancellous bone.

Acetabular revision with impacted morsellised cancellous bone grafting and a cemented cup

This study presents the clinical and radiological results of 62 consecutive acetabular revisions in 58 patients, at a mean of 16.5 years follow-up (15 to 20). The Kaplan-Meier survivorship for the cup with end-point revisions for any reason, was 79% at 15 years (95% confidence interval (CI); 67 to 91). Excluding two revisions for septic loosening at three and six years, and one revision of a well-fixed cup after 12 years in the course of a femoral revision, the survivorship was 84% at 15 years (95% CI; 73 to 95). At review there were no additional cases of loosening, although seven acetabular reconstructions showed radiolucent lines in one or two zones. Acetabular revision using impacted large morsellised bone chips (0.7 cm to 1.0 cm) and a cemented cup, is a reliable technique of reconstruction, when assessed at more than 15 years.

Impacted morselized cancellous bone: mechanical effects of defatting and augmentation with fine hydroxyapatite particles

Geotechnical engineering testing techniques were used to study the mechanical properties of morselized cancellous bone (MCB) and the effects of defatting and augmentation with fine hydroxyapatite (HA) particles. Bovine and human cancellous bone was morselized, rinsed, and manually squeezed to remove excess fluid, producing a standard surgical MCB sample that was also used as a control. Some of the MCB was defatted with heat and detergent and mixed with HA particles in ratios ranging from 0% to 100% HA. Compaction tests were used to determine the effects of moisture content and the amount of MCB that can be packed into a confined space. One-dimensional consolidation tests were used to determine the uniaxial strain behavior, confined modulus, and steady-state creep rate. The compaction tests demonstrated that defatting and adding HA particles significantly increased density. The one-dimensional consolidation tests showed that strain was decreased, modulus was increased and the creep rate was decreased by defatting and adding HA.