Analyzing the behavior of a porous nano-hydroxyapatite/polyamide 66 (n-HA/PA66) composite for healing of bone defects

Figures & data

Figure 1 The morphology of porous n-HA/PA66 composite.

Notes: (A) A porosity of 75%–85% and an average pore size of 500 microns; (B) A size of 4 × 2 × 2 mm³.

Abbreviation: n-HA/PA66, nano-hydroxyapatite/polyamide 66.

Table 1 Details of patients after implantation of the porous n-HA/PA66 composite

Number	Age	Sex	Diagnosis	Location	Bone grafting	Follow-up	MSTS	Radiographic finding	G/N ratio
1	37	F	FD	Right proximal femur	30 g	5.2 years	29	Complete incorporation	0.82
2	20	F	BC	Left heel bone	10 g	5.5 years	30	Complete incorporation	0.41
3	18	M	BC	Right proximal femur	25 g	5.5 years	29	Complete incorporation	0.75
4	27	M	GCT	Left distal femur	25 g	5.4 years	29	Complete incorporation	0.74
5	34	F	FD	Right femur	25 g	5.1 years	30	Complete incorporation	0.82
6	49	F	FD	Right proximal tibia	10 g	5 years	29	Complete incorporation	0.75
7	36	F	BC	Right proximal humerus	20 g	5.2 years	29	Complete incorporation	0.79
8	21	M	FD	Left proximal femur	20 g	5.5 years	30	Complete incorporation	0.78
9	28	M	BC	Right proximal tibia	30 g	5.5 years	28	Complete incorporation	0.78
10	21	F	GCT	Right proximal femur	30 g	5 years	29	Complete incorporation	0.77
11	24	F	FD	Left distal femur	20 g	5.2 years	29	Complete incorporation	0.62
12	39	M	GCT	Left proximal femur	20 g	5.3 years	29	Complete incorporation	0.78
13	49	M	GCT	Left distal femur	15 g	5.5 years	30	Complete incorporation	0.75
14	18	F	BC	Right proximal femur	20 g	5 years	30	Complete incorporation	0.84
15	23	F	BC	Right distal femur	20 g	5.2 years	30	Complete incorporation	0.79
16	31	M	GCT	Right proximal tibia	10 g	5.3 years	30	Complete incorporation	0.92
17	43	M	GCT	Right proximal tibia	20 g	5 years	29	Complete incorporation	0.88
18	56	F	GCT	Right proximal femur	30 g	5.4 years	29	Complete incorporation	0.86
19	47	F	GCT	Right distal femur	15 g	5.4 years	29	Complete incorporation	0.78
20	55	F	GCT	Left proximal humerus	20 g	5.5 years	28	Complete incorporation	0.70
21	20	M	FD	Right proximal femur	25 g	5.1 years	30	Complete incorporation	0.83

Abbreviations: n-HA/PA66, nano-hydroxyapatite/polyamide 66; F, female; M, male; FD, fibrous dysplasia of bone; G/N ratio, grafting-to-non-lesion ratio; BC, bone cyst; GCT, giant cell tumor; MSTS, Musculoskeletal Tumor Society score.

Figure 2 Determination of the grafting-to-non-lesion count ratio (G/N ratio).

Figure 3 Figure showing how the amount of new bone and calcium crystals increased as the time goes on.

Notes: Bone and calcium crystals at (A) 2 weeks, (B) 8 weeks, (C) 12 weeks, and (D) 26 weeks. Masson staining was used, x200 magnification. After 26 weeks, interconnected porosity was filled completely with new bone tissue, which integrated into a whole.

Abbreviations: M, material; B, bone.

Figure 4 The SEM images (×2,000 magnification) of the porous n-HA/PA66 composite with implantation into the rabbit tibia.

Notes: The interface of material and bone at (A) 2 weeks, (B) 8 weeks, (C) 12 weeks, and (D) 26 weeks. After 26 weeks, the porous n-HA/PA66 composites integrated with host bone completely.

Abbreviations: SEM, scanning electron microscope; n-HA/PA66, nano-hydroxyapatite/polyamide 66; M, material; B, bone.

Table 2 Statistical data on 21 patients

Variable	Total (N=21)	G/N ratio	F	P
Agea	21	0.77±0.10	0.87	0.36
Sexb
Female	12	0.75±0.12	1.42	0.33
Male	9	0.80±0.06
Diagnosisb			0.83	0.45
GCT	9	0.80±0.07
FD	6	0.77±0.08
BC	6	0.73±0.16
Locationb			9.65	0.01
Metaphysis	12	0.67±0.10
Diaphysis	8	0.85±0.03
Bone grafted massb			1.02	0.33
≤20 g	13	0.73±0.16
>20 g	8	0.78±0.07

Note:

a Correlation between the two variables was analyzed with linear correlation

b one-way analysis of variance (ANOVA).

Abbreviations: G/N ratio, grafting-to-non-lesion ratio; FD, fibrous dysplasia of bone; BC, bone cyst; GCT, giant cell tumor.

Figure 5 A 20-year-old man suffering from fibrous dysplasia of the right proximal femur.

Notes: (A) The original image of the defect site. Periodic radiological assessments showed (B) during the period of 6 months, 50% of the grafting zones were replaced by new bones, and (C) fully occupied at 1.5 years after surgery. (D) With a more than 5 years follow-up, the porous n-HA/PA66 composite had been completely incorporated with the host bone. (E and F) grafting-to-non-lesion count ratio was 0.83, the patient was satisfied with the result, and the MSTS was 30.

Abbreviations: n-HA/PA66, nano-hydroxyapatite/polyamide 66; MSTS, Musculoskeletal Tumor Society score.

Figure 6 Images of a 47-year-old woman treated by a giant cell tumor resection and fixed with an internal steel plate after the porous n-HA/PA66 composite grafted in the right distal femur.

Notes: Periodic radiological assessments showed that the new bones developed and the porous n-HA/PA66 composite incorporated with the host bone gradually. The internal steel plate was still rigidly fixed and no joint surface subsidence occurred. (A) Preoperative; (B) a half-year after resection; (C) 1 year; and (D) 5 years later. The grafting-to-non-lesion count ratio was 0.78 and the MSTS score was 29 after 5 years follow-up (E and F).

Abbreviations: n-HA/PA66, nano-hydroxyapatite/polyamide 66; MSTS, Musculoskeletal Tumor Society score.

Figure 7 Comparing the G/N ratio between the metaphyseal and diaphyseal areas where the porous n-HA/PA66 composites were implanted after bone tumor resection.

Abbreviations: G/N ratio, grafting-to-non-lesion ratio; n-HA/PA66, nano-hydroxyapatite/polyamide 66.

Figure 8 Images of the female patient that did not meet inclusion criteria due to recurring giant cell tumor.

Notes: A woman, 46 years, suffered from giant cell tumor of the right proximal tibia and had shown recurrence after a follow-up of 2 years. She received treatment by tumor resection and single implantation of the porous composite. (A and B) show the X-ray image and magnetic resonance image of GCT recurrence; (C and D) show the histological images of GCT recurrence, (C) HE ×100, (D) HE ×200).

Abbreviations: n-HA/PA66, nano-hydroxyapatite/polyamide 66; GCT, giant cell tumor; M, material; B, bone; T, tumor; HE, hematoxylin and eosin staining.