A Comparison of Mineral Bone Graft Substitutes for Bone Defects


Table 3 (cont.): Study (Reference) Vehicle


(Trade Name)


Mattsson et al., CP cement (Norian SRS)


200685


Johal et al., 200891


CP cement (α-BSM)


Russell et al., CP cement (α-BSM)


200890 (Collagraft)


Design


Condition: Comparison


Prospective Femoral neck controlled


fractures: Norian SRS versus nothing


Prospective Calcaneus fractures: I controlled


Alpha-BSM versus nothing


Prospective Tibial plateau controlled


Chapman et al., HA/TCP + BTIC Prospective Long bone 199792


controlled fractures:


Collagraft versus ICBG


I


fractures: Alpha- BSM versus ICBG


I 297 24 97 12 47 12


Level Number I 118


Mean FU (Months)


24


Findings


Norian: statistically increased mobility <6 weeks, increased revisions; authors do not recommend use


α-BSM: statistically improved Bolher’s angle at 6 months and 1 year


α-BSM: statistically decreased articular subsidence (>2mm)


Unable to find differences with regard to union (88% power) or function; 5% developed bovine collagen antibodies without sequelae


α-BSM = alpha-bone substitiure material; β-TCP = beta-tricalcium phosphate; BTB = bone–tendon–bone; BTIC = bovine type I collagen; CA = carbonated apatite; CAl = calcium aluminate; CP = calcium phosphate; CS = calcium sulfate; CT = computed tomography; FU = follow-up; HA = hydroxyapatite; ICBG = iliac crest bone graft; N/A = not applicable; NS = not specified; PLA = polylactic acid; SF-36 = Short-Form 36 health questionnaire; Si-CP = silicon–calcium phosphate. Trademarks: FormPutty® (Theken Spine; Akron, OH), Vitoss® (Orthovita; Malvern, PA), Osteoset® (Wright Medical Technology; Arlington, TN), Prodense® (Wright Medical Technology; Arlington, TN), Actifuse® (ApaTech; London, UK), Pro Osteon® (Interpore; Irvine, CA), OSferion® (Olympus; Tokyo, Japan), BoneSource® (Stryker; Mahwah, NJ), Norian SRS® (Synthes; Paoli, PA), Alpha-BSM® (Depuy; Warsaw, IN), Collagraft® (Zimmer; Warsaw, IN).


age and bone quality, are important factors affecting the integration of β-TCP into host bone.70


In a level III retrospective study comparing HA


(Bonfil) with β-TCP (OSferion) in 53 patients with benign bone tumors, both groups had two pathologic fractures (7.6% overall). The authors found β-TCP to be a more attractive bone graft substitute since it showed evidence of graft resorption and new bone formation in all cases. One patient with subchondral giant cell tumor treated with HA graft sustained varus deformity requiring surgical revision.71


While most TCP ceramics are made through a high-pressure sintering technique with compaction, new proprietary formation techniques have been developed that may make these implants more biochemically favorable.4


an ultraporous β-TCP (Vitoss) that has been the subject of several studies. Vitoss consists of 75% 100–1,000µ pores for bone ingrowth and 25% smaller (<100µ) pores, theoretically aiding in diffusion.4,44


In a review


of six cases where Vitoss was used in human fractures, no adverse reactions were seen. One case of biopsy nine months post-operatively showed new bone formation, no inflammatory reaction, and ‘significant quantities of the graft remaining.72


The


post-operative fracture. Hak describes another proprietary process of β-TCP (x-link, TrueForm, FormPutty) formation that has been developed in which the β-TCP is laid down one layer at a time, creating 3D geometry that also allows for increased scaffolding, implantation of cells and factors, and bone ingrowth.5


In an interesting canine humerus


defect model, FormPutty, Vitoss, autograft, and no graft at all were compared head to head histopathologically and mechanically.75


Both One such proprietary technique of β-TCP machining creates


FormPutty and Vitoss had statistically increased tissue reaction scores at 12 weeks compared with autograft and no-graft sites. There was also a statistically increased reaction at 12 weeks with FormPutty and Vitoss compared with their six-week marks. Both TCPs had a statistically decreased residual graft at 12 weeks compared with six weeks. There were no significant differences found between any of the groups in terms of new bone formation, residual implant, yield force, stiffness, or failure force at 12 and 24 weeks. In a level II prospective study of 18 ankle fusions treated with x-link granules, the authors noted an 85% fusion rate at a mean of four months, with no graft complications.76


Calcium Phosphate Cements In a retrospective radiographic case


series, 60 patients with cavitary bone defects were treated with Vitoss. Bone marrow aspirate and resorption were determined on X-ray.73


authors noted that resorption and trabeculation increased steadily with time. One out of 60 cases (1.7%) had a pathologic fracture. There was no difference in graft incorporation rate based on age, size of defect, or use of local adjuvant treatment. Another retrospective review of 24 patients with cavitary lesions created after curettage of a benign bone tumor filled with Vitoss found faster resorption and statistically faster trabeculation for smaller lesions (<43cc) at all time intervals of three, six, nine, and 12 months, with trabeculation lagging behind resorption.74 None of the lesions was fully resorbed at 18-month follow-up. The graft in soft tissues was seen in most patients at six weeks, all of which eventually resorbed. Two patients (8.3%) had extrusion of the graft from the incision that resolved. Another two patients (8.3%) sustained


US ONCOLOGY & HEMATOLOGY


Neither HA nor TCP has greater compressive strength than cancellous bone and cannot be used in situations where greater strength is required. Studies using high-level investigations have analyzed the use of calcium phosphate cement in the treatment of fractures that require structural support. Although these studies involve traumatic and not true cavitary bone defects, their high level and potential applicability to tumor surgery warrants their mention. A modification of traditional TCPs, these injectable compounds consist of combinations of calcium phosphate, TCP, and calcium carbonate, which upon mixture and exothermic or isothermic crystallization reaction change from a temporary liquid into solid dahilite or carbonated apatite. This is similar to the mineral phase of bone, with greater compressive strength than cancellous bone.4,5


These substances set in less than 10 minutes and achieve maximal compressive strength at 24 hours. One study showed that its calcium phosphate cement had an initial set time of 2.75


45


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