Bone Graft (Substitutes) in Distal Radius Fractures





Key Points





  • The use of bone grafts or bone graft substitutes for treatment of comminuted distal radius fractures is dictated by tradition, training, and personal experience.



  • The use of bone grafts (substitutes) for treatment of comminuted distal radius fractures does not improve outcome in elderly patients.



  • The use of autologous bone graft is characterized by a significant number of complications related to the procedure of harvesting.





Panel 1: Case Scenario


A 50-year-old male presents with a grade 2 open comminuted distal radius and ulna fracture after a motor vehicle accident. Initial treatment consists of debridement of the wound, removal of devascularized bone and stabilization by means of joint-spanning external fixation. Postoperative radiographs show a comminuted extraarticular distal radius and ulna fracture with a significant segmental metaphyseal defect of 5 cm of the distal radius ( Fig. 1 ).




Fig. 1


Radiographs after initial stabilization in an external fixator. Comminuted extraarticular distal radius and ulna fracture with a significant segmental metaphyseal defect of 5 cm of the distal radius.


What is the most effective approach for this metaphyseal defect in this patient?



Importance of the Problem


Principles of treatment of distal radius fractures have changed in the last decades. While in the past, alignment of the bony fragments and maintenance of radial length were considered to be most important, nowadays meticulous reduction of the articular surface and adequate reconstruction of metaphyseal comminution along with reliable stabilization are key principles in most surgically treated distal radius fractures.


As more patients presenting with distal radius fractures are of older age, many clinicians are confronted with problems of osteoporosis when treating distal radius fractures. Osteoporotic fractures have an impaired ability to heal and often require more time to heal. The degree of comminution is generally high and alignment is often lost, despite of some remaining healing potential of osteoporotic bone. As a result, metaphyseal comminution and impaction, especially in patients with osteoporotic bone, may result in a metaphyseal bony void with subsequent instability, loss of reduction, and malunion. This may lead to serious functional impairment on short and long term.


Although healing of metaphyseal defects in distal radius fractures can be a slow process, the risk of nonunion in distal radius fractures is minimal. As a consequence, bone grafts or bone graft substitutes are primarily used to provide structural stability and thereby support early return to function. By using bone grafts or bone graft substitutes for treatment of bony defects in the distal radius, the construct can be stabilized by providing mechanical support for the radiocarpal joint surface and a scaffold for ingrowth of new bone is provided. The ideal implanted material is biocompatible, bio-resorbable and will lead to optimal structural stability by providing substantial initial compression strength while allowing rapid ingrowth of new bone with preservation of anatomical reduction of the joint surface.


Addressing bone defects as part of primary treatment of distal radius fractures is a challenge for the treating surgeon, since outcome of the fracture is dependent on how successful the defect is treated. Remodeling of metaphyseal defects in distal radius fractures that are fixated without additional bone graft or bone graft substitute does not lead to optimal bone quality after trabecular modeling. Additionally, clinical evidence supports the hypothesis that the use of bone graft substitutes for treatment of metaphyseal defects may lead to faster healing. On the other hand, structural stability is also directly influenced by the method of fixation. As advances in plate design have led to the applicability of anatomically shaped and variable angle locking plates in recent years, perhaps bone graft substitutes are not essential in most situations.


Main Question





  • What is the role and additional value of bone graft substitutes in comminuted distal radius fractures?



  • Which type of bone graft is most effective for treatment of bone defects in comminuted distal radius fractures? (autograft, allograft, or bone substitutes)



Current Opinion


There are many surgical options for treatment of metaphyseal bone defects in distal radius fractures including autografts, allografts and bone substitutes, both biological and synthetic. However, the use of bone grafts or bone graft substitutes for treatment of comminuted distal radius fractures is dictated by tradition, training, and personal experience. In highly exceptional cases of bone defects larger than 6–8 cm, vascularized bone grafts are recommended. Strategies based on potential robust scientific evidence are very limited for treatment of bone defects in comminuted distal radius fractures.


Finding the Evidence


We provide below a list of search algorithms used to retrieve evidence for the main question:




  • Cochrane search: “distal radius fracture” OR “distal radial fracture” AND “bone substitutes”



  • Pubmed (Medline): “Radius Fractures” [Mesh] OR “radius fracture” [tiab] OR “radial fracture” [tiab] OR “distal radius fracture” [tiab] OR “distal radial fracture” [tiab] AND “Bone Substitutes” [Mesh] OR “bone substitutes” [tiab]



  • Only articles written in English, French or German were included.



  • Study protocols or abstracts of oral or poster presentations at congresses were excluded.



Quality of the Evidence


Overall, we found one cochrane systematic review and six prospective studies of relevance to the use of bone grafts or bone graft substitutes for treatment of distal radius fractures. We also found one level 3 study and one level 4 case series.


Level I: Systematic review: 1


Level II: Randomized trial with methodological limitations: 6


LEVEL III: Case-controlled study: 1


Level IV: Case series: 1


Findings


Evidence From Level-I Studies


A Cochrane systematic review from 2008 provided the only level-1 evidence available.


For this review randomized or quasirandomized controlled clinical trials evaluating the use of bone grafts or bone graft substitutes for treatment of distal radius fractures in adults were included. Overall, 10 trials involving 874 adults with distal radius fractures were included in this review. All trials showed significant heterogeneity and no trial had proof of allocation concealment. For this reason, trials could be considered as level-2 evidence.


Overall, six comparisons regarding the use of bone grafts or bone graft substitutes could be made.



  • (1)

    Four trials with 239 participants compared the use of bone scaffolding with plaster cast immobilization for comminuted distal radius fractures. Improved anatomical outcomes were obtained when using bone grafts or bone graft substitutes. Differences between the intervention group and control group were significant with regards to dorsal angulation in favor of the intervention group ( Fig. 2 ). The type of bone scaffolding used was quite different among studies. (Autogenous bone graft, Norian SRS, a calcium phosphate bone cement or methylmetacrylate cement. ) Two studies showed that improved functional outcomes were obtained in the bone substitute group. Significantly more patients in the bone substitute group obtained excellent or good results ( Fig. 3 ).




    Fig. 2


    Differences between the intervention group and control group regarding dorsal angulation.



    Fig. 3


    Differences between the intervention group and control group regarding functional outcome.


  • (2)

    One trial with 323 participants compared the use of percutaneous application of Norian SRS calcium phosphate cement to plaster cast or external fixation after closed reduction. Subjects were followed clinically and radiographically up to 1 year. Initial functional recovery was faster in the Norian group, but no differences in functional outcome were seen at 1 year. No clinically relevant differences in anatomical outcomes were seen at 1 year. There were significantly more infections in the control group, always related to external fixator pins or Kirschner wires (16.7% vs 2.5%, P < .001). Subjects in the intervention group showed significantly more complications due to extraosseous Norian SRS deposits.


  • (3)

    One trial with 48 participants reported outcomes of autologous bone graft with surgical fixation by means of external fixation compared with surgical fixation alone. All subjects had severely displaced and comminuted distal radius fractures. At 1-year follow up, there were no significant differences in functional outcome or anatomical measurements. There was no significant difference in numbers of malunions between both groups.


  • (4)

    One trial with 21 participants compared the use of hydroxyapatite cement with Kapandji’s intrafocal pinning in 21 subjects with intraarticular distal radius fracture. Grip strength was significantly worse in the bone substitute group (56% vs 73%). Furthermore, subjects in the bone substitute group showed significantly less palmar flexion at 6 months follow up (mean difference − 10 degrees, 95% CI − 18.89 to − 1.11 degrees). No complications occurred in either group.


  • (5)

    Three trials with 180 participants with secondary displaced distal radius fractures compared the use of autogenous bone or bone substitutes (Norian SRS or methylmetacrylate cement ) with external fixation. No significant differences in functional outcome were seen between both groups. However, anatomical outcomes were somewhat superior in the groups using autogenous bone or bone substitutes when compared to external fixation only.


  • (6)

    One trial compared allogenic bone-graft substitutes with autologous bone graft for repair of comminuted distal radius fractures in 93 patients undergoing open reduction and dorsal plate fixation. No clinically significant differences were seen regarding functional outcome between both groups. There was a significant number of complications in the autograft group due to the harvesting from the iliac crest. Half of these patients suffered postoperative pain and 13 patients still reported complaints of pain 1 year after iliac crest harvesting.



Overall, results from this review led to the conclusion that the use of bone grafts or bone graft substitutes for treatment of comminuted distal radius fractures may improve anatomical outcomes when compared to treatment with a cast alone, but there was insufficient evidence to draw any conclusions regarding other comparisons. No conclusions can be drawn with regards to functional outcome or safety.


Evidence From Level-II Studies


Two studies compared the use of bone graft substitutes with nonoperative treatment for comminuted distal radius fractures. Their data could not be pooled due to heterogeneous treatment groups.


Except for improved ulnar variance in favor of the calcium phosphate bone cement group in one study, no significant differences with regards to clinical, functional, and radiographical outcome were seen at final follow up.


One study compared percutaneous pinning and cast immobilization with the use of injectable calcium phosphate bone cement with supplemented pin or screw fixation in 52 menopausal women with unstable intraarticular distal radius fractures. Subjects were evaluated clinically and radiographically at 2 years.


Patients treated with injectable calcium phosphate had better DASH scores, better active range of motion in frontal and sagittal plane, better forearm rotation, and better grip strength ( P < .001). Additionally, there was a significantly higher loss of reduction (radial length, radial inclination, and palmar tilt) in the control group ( P < .001).


Two studies randomized between plate osteosynthesis with additional bone graft substitute and plate osteosynthesis alone in distal radius fractures. Data could not be pooled successfully because of the fact that groups were too heterogeneous. In one study, both intra- and extraarticular unstable distal radius fractures in an elderly population of 48 subjects were randomized between volar plate osteosynthesis alone and a combination of volar plate osteosynthesis and augmentation with calcium phosphate bone cement. No statistic differences in clinical or radiographic outcome were seen between subjects at 1 year follow up.


In the other study, 39 patients with intraarticular fractures of the distal radius were randomized in 2 groups, one being treated with internal fixation by means of dorsal plating only while the second group received an additional bone graft substitute (compressed beta-tricalcium phosphate granules). Subjects were followed clinically and radiographically up to 1 year. There was no statistically significant difference in functional or radiological outcome between groups at 12 months postoperatively, and complications were similar.


One study assessed clinical and radiological outcome of cancellous allograft compared to autologous bone grafting in comminuted distal radius fractures. Ninety patients were randomized between allograft or autologous bone grafting. Subjects were followed for 12 months. Regarding range of motion, grip strength and radiological outcome parameters, no significant differences between groups were seen. Obviously, there were more complications related to the procedure of iliac crest bone graft harvesting. One year postoperatively, six patients (13%) still suffered from discomforting paresthesias of the upper lateral thigh. Operating time was significantly shorter in the allograft group ( P = .03).


Evidence From Level-III Studies


One study assessed radiographic outcomes of hydroxyapatite bone graft substitute augmentation for volar plate osteosynthesis compared to volar plate osteosynthesis alone in elderly patients with comminuted distal radius fractures. There were no significant differences between groups in terms of palmar tilt ( P = .80) or radial inclination ( P = .17). Ulnar variance increased significantly in the group treated with volar plate osteosynthesis alone ( P < .05).


Evidence From Level-IV Studies


One study assessed functional, clinical, and radiological outcomes of synthetic hydroxyapatite bone graft substitute with closed reduction and Kirschner wire fixation for unstable distal radius fractures in elderly patients. At 16 weeks postoperatively, subjects showed satisfactory clinical outcome without metaphyseal collapse in all fractures.


In recent literature, there are reports of successful reconstruction of large posttraumatic bone defects in distal radius fractures with free vascularized grafts, especially free vascularized fibular grafts. Although the majority of free vascularized fibular grafts are used for reconstructive option in patients with septic skeletal defects, they are also applied for indications of posttraumatic bony defects larger than 6–8 cm, often accompanied by poor vascularity of the surrounding soft tissues ( Figs. 4–10 ). This technique offers the advantage of a 1-stage reconstruction, in which bony reconstruction and soft tissue coverage are addressed in a single procedure. However, experience in microsurgical techniques and careful postoperative surveillance is mandatory and satisfactory anatomical and functional outcomes have been achieved by the authors when addressing bone defects larger than 6–8 cm with nonvascularized techniques, such as the Masquelet technique, as well. As a result, the latter technique may be the preferred technique in the majority of cases when addressing large metaphyseal bone defects in distal radius fractures.


Mar 15, 2021 | Posted by in RHEUMATOLOGY | Comments Off on Bone Graft (Substitutes) in Distal Radius Fractures
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