Calcium‐Based Bone Substitutes

Calcium‐Based Bone Substitutes

Ross Leighton BSc MD FRCSC1, Kelly Trask BEng MSc CCRP1, Thomas A. Russell MD2, Mohit Bhandari MD MSc3 and Richard E. Buckley MD FRCSC4

1QEII Health Sciences Centre, Division of Orthopaedic Surgery, Halifax Infirmary, Halifax, NS, Canada

2University of Tennessee Campbell Clinic Department of Orthopaedic Surgery, Eads, TN, USA

3Department of Surgery, McMaster University, Hamilton, ON, Canada

4Division of Orthopaedic Surgery, Department of Surgery, University of Calgary, Calgary, AB, Canada

Clinical scenario

  • A 54‐year‐old female presents with a fractured tibial plateau following a low energy injury at home.
  • The patient’s X‐rays indicate a split depression injury laterally, with an associated medial condylar injury with a posterior medial split.

Top three questions

  1. In periarticular fractures with joint depression, can calcium phosphate bone substitutes enhance the standard fixation when compared with autogenous bone grafting and fixation or fixation alone?
  2. In patients with a fracture requiring bone graft augmentation, does the use of calcium phosphate cement instead of autogenous iliac crest bone graft result in fewer complications?
  3. In osteoporotic fractures, does calcium phosphate augmentation improve fixation of implants when compared with no augmentation of fixation?


Periarticular fractures are common injuries that result from indirect coronal and/or direct axial compressive forces. As the patient ages, the fracture pattern is usually a split depression type without associated ligamentous injury. Surgical guidelines advocate anatomic reduction, re‐establishment of the long bone alignment, subchondral bone grafting to support the articular cartilage, and stable internal fixation.1

Clinical comment

Metaphyseal fractures are among the most difficult fractures to treat. Depressed articular fragments can crush the underlying weak subchondral cancellous bone, leaving a void when the articular segments are reduced surgically. Potential long‐term problems including pain, post‐traumatic arthritis secondary to apoptosis of the chondrocyte, and limitation of motion and function might occur if joint surface subsidence cannot be prevented or at least limited.

Available literature and quality of the evidence

Russell et al. compared the treatment of subarticular bone defects in tibial plateau fractures with conventional autogenous iliac bone graft (AIBG) to bioabsorbable calcium phosphate paste (alpha‐BSM, Etex Corporation) in a randomized controlled trial (RCT).1 All fractures united in both groups within the same time periods.

There was an unexpected statistically significant (p = 0.009, Fisher’s exact two‐tailed test) higher rate of articular subsidence in the AIBG group compared to the alpha‐BSM group. Subsidence of equal to or greater than 2 mm on the anteroposterior radiographs was found in 31% of patients in the AIBG group compared to 8% in the alpha‐BSM group in the final evaluation. This provided level I evidence that bioabsorbable calcium phosphate material, such as alpha‐BSM, appeared to be a better choice for the treatment of subarticular defects than AIBG in tibial plateau fractures.

Johal et al. performed a similar RCT on os calcis fractures comparing open reduction and internal fixation (ORIF) plus alpha‐BSM to ORIF alone in the treatment of calcaneal bone voids encountered after operative treatment of displaced intra‐articular fractures of the calcaneous.2 There was no difference between the groups in the degree of collapse of Bohler’s angle at six weeks and three months when compared to initial postoperative values. However, at six months the mean collapse of the alpha‐BSM and ORIF group was 5.6° (standard deviation [SD] 4.5) and ORIF alone was 9.1° (SD 5.8). This was statistically significant (p <0.01).


Level I evidence suggests that the addition of calcium phosphate to internal fixation in periarticular fractures is more supportive than fixation alone or fixation with autologous bone graft. Although the radiographic outcomes were better with calcium phosphate, these studies were not powered to detect differences in patient‐reported outcome scores.

Resolution of clinical scenario

  • For ORIF of tibial plateau fractures, calcium phosphate reduces articular subsidence better than autogenous iliac crest bone graft.
  • For ORIF of os calcis fractures, calcium phosphate reduces articular subsidence better than fixation alone.

Question 2: In patients with a fracture requiring bone graft augmentation, does the use of calcium phosphate cement instead of autogenous iliac crest bone graft result in fewer complications?


Autogenous bone graft, typically from the iliac crest, has been stated in the past to be the gold standard of bone grafting. However, it is associated with donor site morbidity including chronic pain and wound complications.39 Calcium phosphate cement has increased compression strength and improved custom‐filling of bone defects. However, any alternative graft material should have a better risk/benefit profile than the current standard.

Clinical comment

Alternative grafting materials for filling fracture voids include allograft and synthetic bone materials. While using allograft avoids the donor site morbidity associated with autograft, it also can lead to complications including potential disease transmission, host–donor incompatibility, and possibly lower union rates.1012 Therefore, synthetic bone materials, such as calcium phosphate bone cement, appear to be an attractive alternative. They perform better acutely and over the first year and lack the disadvantage of bone site morbidity or the potential for infection and disease transmission associated with allograft.

Available literature and quality of the evidence

There are several narrative review articles that address the use of bone grafting in fractures and trauma situations.316 In addition, Bajammal et al. have completed a meta‐analysis (level I evidence) of studies comparing calcium phosphate bone cement to bone graft.17 The meta‐analysis included 14 RCTs. The studies had documented outcomes that included pain, maintenance of fracture reduction, infection, and functional outcomes.


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Nov 28, 2021 | Posted by in ORTHOPEDIC | Comments Off on Calcium‐Based Bone Substitutes
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