CASE SERIES

https://doi.org/10.5005/jojs-10079-1130
Journal of Orthopedics and Joint Surgery
Volume 6 | Issue 1 | Year 2024

Effect of Synthetic Bone Graft Substitutes in Management of Nonunion in Long Bones: A Case Series

Muthamilselvan Kumanan1, Manikandan Navaneethakrishnapandian2, Mohamed Ibrahim3

1–3Department of Orthopaedics, Tirunelveli Medical College Hospital, Tirunelveli, Tamil Nadu, India

Corresponding Author: Manikandan Navaneethakrishnapandian, Department of Orthopaedics, Tirunelveli Medical College Hospital, Tirunelveli, Tamil Nadu, India, Phone: +91 9443164800, e-mail: nithishkowshik@gmail.com

Received: 14 June 2023; Accepted: 10 October 2023; Published on: 12 January 2024

ABSTRACT

Introduction: Treating nonunion is a major concern for any orthopedic surgeon. Preparation of autograft for use in nonunion itself is associated with various complications, starting from donor site morbidities to postoperative wound infections. To overcome these complications, an artificial substance that is biocompatible, which mimics all the properties of an autograft, may be an ideal thing for the management of nonunion. One such thing that was put forth in our study is ”Synthetic Bone Graft.” All the pros and cons and their effectiveness in today’s modern orthopedic management of nonunion are discussed below.

Aim: To evaluate the efficacy and outcome of synthetic bone grafting substances in the management of nonunion in long bones.

Materials and methods: This is a cross-sectional study. Patients with noninfected nonunion are selected. A total of 20 patients were treated with specific fracture fixation augmented with synthetic bone grafts and were followed for about 18 months in the Department of Orthopaedics, Tirunelveli Medical College Hospital, Tirunelveli, Tamil Nadu, India.

Results and discussion: In our study of 20 cases with nonunion of long bones, 90% of cases (18 cases out of 20 cases) showed clinical and radiological union among our case study. A bone substitute with the composition of tricalcium phosphate and calcium sulfate is used in our study. Functional and radiological outcomes of synthetic bone graft materials in the management of nonunion in long bones showed far better results compared to other bone graft materials. In the future, the use of these synthetic bone graft materials in bone regeneration under specific indications and with safety roles will simulate the normal bone formation cascade with reduced morbidity and cost in the long-term.

How to cite this article: Kumanan M, Navaneethakrishnapandian M, Ibrahim M. Effect of Synthetic Bone Graft Substitutes in Management of Nonunion in Long Bones: A Case Series. J Orth Joint Surg 2024;6(1):39–43.

Source of support: Nil

Conflict of interest: None

Patient consent statement: The author(s) have obtained written informed consent from the patient for publication of the case report details and related images.

Keywords: Case report, Bone graft substitutes, Calcium sulfate, Calcium triphosphate, Synthetic bone graft substitutes

INTRODUCTION

A major complication for any fracture management is nonunion. Treating nonunion is a major concern for any orthopedic surgeon. When a fracture shows no visible progressive signs of healing, it should be intervened to make the bone into union. Rather than the normal modality of fixation of fracture, it needs to be augmented with bone grafting to unite the nonuniting structures.1 Preparation of autograft for use in nonunion itself is associated with various complications starting from donor site morbidities to postoperative wound infections. To overcome these complications, an artificial substance, which is biocompatible and mimics all the properties of an autograft, may be an ideal thing for the management of nonunion. One such thing was put forth in our study is “Synthetic Bone Graft Substitute.” All the pros and cons and their effectiveness in today’s modern orthopedic management of nonunion were discussed.

SYNTHETIC BONE GRAFT SUBSTITUTES IN MANAGEMENT OF NONUNION

Inclusion Criteria

  • Age 10–60 years.
  • Noninfected nonunion.
  • Bone defects <1 cm.
  • Nonresponsive to conservative treatment.

Exclusion Criteria

  • High-grade malignancies.
  • Patient on immunosuppressive treatments.
  • Metabolic bone disease.
  • Infected nonunion.
  • Larger bone defect >1 cm.
  • Elderly people age >60 years.
  • Pregnancy.
  • Uncontrolled diabetes.

CLINICAL AND RADIOLOGICAL EXAMINATION

MATERIALS AND METHODS

STUDY PROCEDURE

Synthetic Bone Graft Substitute

Bone graft substitute acts as a catalyst for bony union process. It aids the natural healing processes of bone and enables the remodeling capacity of native bony architecture. Bone graft substitute is completely absorbed by 10–12 months and remodeling occurs simultaneously. It is designed to promote regeneration of bone in osseous defects.2

Synthetic bone graft substitute materials used in our study:

  • Combination of β-tricalcium phosphate along with calcium sulfate.
  • Properties of the synthetic bone graft materials used.

β-tricalcium phosphate:

  • Osteoconductive.
  • Chemical composition similar to native bone.
  • Absorption is far better compared to other ceramics.
  • Porosity better to handle.
  • Biodegradation occurs within 6–8 weeks.3
  • Tensile strength and compression property is same as native bone.

Calcium sulfate:

  • Clinical applications for calcium sulfate and even the filling of autogenous bone harvest sites.
  • It transforms into a solid substance through recrystallization.
  • Biodegradation occurs by 8 weeks.
  • Quick resorption is a mechanical disadvantage.

On combining the above two materials such as β-tricalcium phosphate and calcium sulfate characteristics of the bone graft substitute obtained:

  • Remodeling capacity.
  • Inflammatory pyrophosphates are not found.
  • Nonabsorbing compound not used.
  • Osteogenic property.
  • Powerful scaffold for bone growth.
  • Absorption without remains.4

Substitute can be made into paste form and can be injected in desired quantity to the bony void and molded into appropriate shape.

The molded form can be drilled after 15–20 minutes.

INTRAOPERATIVE PREPARATION AND APPLICATION OF SYNTHETIC BONE GRAFT

The bone graft substitute is available in powder form, which is provided along with distilled water for constituting the powder into a semisolid substance so that it can be injected or applied into the desired bone defect or the nonunion area (Figs 1 and 2).

Figs 1A to D: The above picture shows the synthetic bone graft substitute used. It contains: (A) Container for the substitute; (B) Distilled water for reconstituting the substitute; (C) Spatula for mixing the constitute; (D) Syringe for filling and applying the constitute

Fig. 2: Above pictures show reconstituting the substitute for application

CASE ILLUSTRATION

Case 1

  • Name: Mr Raskin.
  • Age/sex: 21/male.
  • IP No: 41085.
  • Diagnosis: Nonunion both bone forearm # (6 months old) right side.
  • Procedure: Open reduction and internal fixation with plating and synthetic bone grafting (Figs 3456).

Fig. 3: Preoperative images

Fig. 4: Six months follow-up

Fig. 5: Intraoperative image

Fig. 6: Clinical image showing patient lifting heavy weight postoperatively on follow-up

Case 2

  • Name: Mrs Mallika.
  • Age/sex: 52/female.
  • IP No: 7810.
  • Diagnosis: Nonunion distal third shaft of femur with failed implant in situ.
  • Procedure: Implant exit followed by open reduction and internal fixation with plating and synthetic bone grafting (Figs 78910).

Fig. 7: Preoperative images

Fig. 8: Eight months follow-up

Fig. 9: Intraoperative image

Fig. 10: Postoperative follow-up

EVALUATION OF THE OUTCOME OBSERVATION

Among the complications, joint stiffness and shortening were the most common, constituting around 75% of cases. Joint stiffness was managed with physiotherapy and the average shortening was about 2 cm, which is within the acceptable limit (Fig. 11 and Table 1).

Table 1: Table showing complications
S. No. Complication Number of cases Percentage (%)
1 Deformity 4 20
2 Nonunion 2 10
3 Surgical wound infection 3 15
4 Joint stiffness 7 35
5 Shortening 7 35

Fig. 11: Complications

RESULTS

In our study of 20 cases with nonunion of long bones, mostly young individuals were studied. A total of 16 were males and four were females; six of them were upper limb cases and 14 being lower limb case, road traffic accident being the most common mode of injury in our study. All the cases were noninfected nonunion and were treated with fracture-specific surgery like plating, nailing, and K-wire fixation, provided all the procedures were augmented with synthetic bone graft material intraoperatively (Fig. 12).5 All the patients were followed up postoperatively, and radiological signs of union of the nonunion bones were assessed. Complications postoperatively were addressed and treated adequately.6 The duration of treatment (time for union) varies from a minimum of 4 months to a maximum of 12 months, with a mean duration of 7.4 months. Nonunion was seen in two patients. Postoperative period infection was seen in three patients. Out of the three infected cases, one patient has gone for nonunion (Fig. 13). The cause for nonunion in another patient is unknown. Other complications like joint stiffness seen in seven patients shortening were seen in seven patients. Around 75% of cases returned to normal life function postsurgery. Around 90% of cases (18 cases out of 20 cases) showed clinical and radiological union in our case study.

Fig. 12: Upper limb vs lower limb cases

Fig. 13: Return to normal function

DISCUSSION

Mechanical stability and a biological microenvironment are required for normal fracture union in long bones. Osteoinductive, osteoconductive, and osteogenic properties are required for an ideal bone graft. Also, an ideal bone graft should provide mechanical support and a biological platform for the bony healing process. Synthetic bone graft substitutes possess two characteristics of an ideal bone graft material (osteointegration and osteoconduction). Ideally, synthetic bone graft substitutes should be biocompatible, show minimal fibrotic reaction, undergo remodeling, and support new bone formation. Also, it should be absorbed from the site of application to aid in remodeling of bone after union.6

A bone substitute fulfilling the abovementioned characteristics is ideal for the application and management of nonunion in long bones.

The chemical composition of tricalcium phosphate is similar to that of native bone. It has better absorption than hydroxyapatite. Absorption is fast, with some weakness in mechanical strength. Biodegradation occurs within 6–8 weeks. Since its compression and tensile strength are very similar to that of cancellous bone, it is used in regions with no mechanical load. Osteoconductive and biocompatible properties of β-tricalcium phosphate (β-TCP) make it possible to inject into bony void and defects.

Calcium sulfate transforms into a solid substance, providing mechanical stability to the area where it is implanted. Following its injection into the bone defect, calcium sulfate typically experiences biodegradation within 6–8 weeks.7

A bone substitute with the composition of tricalcium phosphate and calcium sulfate is used in our study. Thus, it fulfills the requirements of an ideal bone graft substitute. The substitute is available in a sterile package, and its directions of usage are easier for preparation and application in the treatment of nonunion of all long bones. Complications met with autograft harvesting, and the postoperative adverse effects following the autograft harvesting procedure are thus curtailed. Moreover, the union rate following the use of synthetic bone graft materials is almost 90% (18 cases showed union out of 20 nonunion cases). Functional and radiological outcomes of synthetic bone graft materials in the management of nonunion in long bones showed far better results compared to other bone graft materials without any complications resulting from donor site morbidity as encountered in autograft harvesting.

CONCLUSION

Hence, from our study, the management of nonunion in long bones, which is a meticulous procedure and follow-up with donor site morbidities following autograft harvesting, is no longer encountered in the usage of synthetic bone graft materials in nonunion management and follow-up. The functional and radiological outcome of synthetic bone graft materials in the management of nonunion in long bones showed far better results.

Thus, synthetic bone graft substitutes are ideal for the bony healing process under specific indications with reduced morbidity and cost-effective in the long-term.

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