Year 11 Depth Study Report 2023-06-26
Metal reactivity and
compatibility of usage in
orthopaedic procedures
By Students 37317993 & 37316946
Word Count ≈ 2035
Table of Contents
........................................................................................................................................... 1
........................................................................................................................................... 2
Abstract.............................................................................................................................. 3
Introduction......................................................................................................................... 3
Aim..................................................................................................................................... 4
Prediction............................................................................................................................ 4
Materials and Methods.......................................................................................................5
Results................................................................................................................................ 7
Discussion.......................................................................................................................... 9
Conclusion........................................................................................................................ 11
Appendix A: Definitions.....................................................................................................12
Appendix B: Reference List..............................................................................................13
Logbook............................................................................................................................ 15
16/05 Initial Brainstorming................................................................................................21
24/05 Equipment & Risk Assessment...............................................................................23
25/05 Application of Experiment Research.......................................................................25
26/05 Theory Revisions....................................................................................................29
30/05 Practical Revisions..................................................................................................31
01/06 Experiment Preparations........................................................................................34
02/06 Experiment Part 1...................................................................................................38
07/06 Collating Results.....................................................................................................39
08/06 Working on Report..................................................................................................39
09/06 Collecting Data: Mass.............................................................................................39
15/06 Working on Report..................................................................................................39
Table 1: Change in water basicity when reacting to metal (pH) with balanced chemical
equations.......................................................................................................................... 40
★1★
,★2★
,Abstract
Orthopaedic implants restore function and support damaged bones or replace missing joints
due to trauma defects, diseases, or abnormal congenital[1] development. Materials used in these
implants are selected based on biocompatibility, corrosion resistance, and mechanical
properties (Mohamed, 2016a).
The broadening of research into benefits of alternative metal orthopaedic implants reveal
potential improvements in both patient outcomes and technological furtherment. This
experiment aimed to investigate the reactivity of various metals (copper, zinc, and magnesium)
in water and sodium chloride solution at body temperature as a rudimentary in vitro simulation of
their compatibility in common procedural conditions in orthopaedics, i.e. sterilisation and
implantation. It was hypothesised that copper would be less reactive than zinc and magnesium
through knowledge of metal properties (Discussion, p.8), making it the most biocompatible.
Results measuring changes in pH and changes in mass (avg. loss% (Mg) = 2.66%; (Zn) =
0.660%; (Cu) = 0.00%, Fig.1) over 5 days showed that this hypothesis was correct (Mg > Zn >
Cu).
Sources of error were also identified as variations in surface area and temperature fluctuations,
which may have affected the experiment accuracy. Future research could focus on improving
sources of error and investigating supplementary metal alloys as biomaterials to eliminate risks
of corrosion, metal ion release, and inflammation and infection from reactive metals, etc.
Introduction
Metallic implants, known for their strength and durability, are commonly used for load-bearing[2]
orthopaedic prostheses (Mohamed, 2016b). However, recent research aims to cultivate and
incorporate unconventional metallic implants to improve patient outcomes as surgical metals
like stainless steel, cobalt-based alloys, and titanium alloys used in current implants can have
negative post-surgery effects on patients, including stress shielding[3], metal ion releases, and
toxicity (Tsakiris et al., 2021). It is important for metals used in orthopaedic procedures to exhibit
minimal reactivity with bodily fluids, including blood in the periosteum[4] as well as during
sterilisation.
To simulate this, copper, zinc, and magnesium were placed in contact with cold distilled water
and 0.154 mol L-1 sodium chloride solution to replicate standard salt contents in blood (0.9%).
Established observations of the reactivity series as demonstrated by Jackson (2014) sustains
the hypothesis that copper is less reactive than zinc, which is less reactive than magnesium.
Selection of Metals
● Currently commercialised magnesium alloys in orthopaedics include MAGNEZIX® (Mg-Y-
RE-Zr) or RESOMET™ (Mg-Ca) in bioabsorbable screws and pins (Kose, 2019). The main
advantage to this field involves magnesium’s special osteoconductive[5] properties,
dissolution in bodily fluids, and harmless corrosion products even in the case of hydrogen
emission (Hassan et al., 2022; Antoniac et al., 2022).
● Zinc has potential for bioabsorbable orthopaedic implants as it exhibits promising
biodegradation behaviour, already prevalent in medical treatments such as in ointments,
cream, powders, etc, which require non-reactiveness with bodily fluids (Su et al., 2023).
★3★
, ● Due to copper’s antibacterial properties, its promising uses in water, wound dressings, and
medical equipment to prevent infections are currently investigated. E.g. An ongoing study
on osteomyelitis[6] implants by the Royal College of Surgeons in Ireland combines copper
ions with bioactive glass and collagen, found to cause a 3.6-fold increase in bone
development (Ryan et al., 2019).
Figure 0.1: Applications of biodegradable magnesium Figure 0.2: (A) Osteosynthetic
implants: (a) cardiovascular stents; (b) screws for zinc alloy plate and screws, (D)
orthopaedic fixation; (c) biodegradable microclips; (d) Fixed mandibular bone
biodegradable orthopaedic implants; (e) wound-closing fractures immediately after
devices. (Bordbar-Khiaban et al., 2019) surgery. (Wang et al., 2019)
Aim
To investigate the reactivity and biocompatibility of various metals by simulating conditions in
orthopaedic procedures.
Prediction
Copper will be less reactive to cold water and NaCl solution than zinc and magnesium, and thus
more biocompatible in orthopaedic procedures.
★4★
Metal reactivity and
compatibility of usage in
orthopaedic procedures
By Students 37317993 & 37316946
Word Count ≈ 2035
Table of Contents
........................................................................................................................................... 1
........................................................................................................................................... 2
Abstract.............................................................................................................................. 3
Introduction......................................................................................................................... 3
Aim..................................................................................................................................... 4
Prediction............................................................................................................................ 4
Materials and Methods.......................................................................................................5
Results................................................................................................................................ 7
Discussion.......................................................................................................................... 9
Conclusion........................................................................................................................ 11
Appendix A: Definitions.....................................................................................................12
Appendix B: Reference List..............................................................................................13
Logbook............................................................................................................................ 15
16/05 Initial Brainstorming................................................................................................21
24/05 Equipment & Risk Assessment...............................................................................23
25/05 Application of Experiment Research.......................................................................25
26/05 Theory Revisions....................................................................................................29
30/05 Practical Revisions..................................................................................................31
01/06 Experiment Preparations........................................................................................34
02/06 Experiment Part 1...................................................................................................38
07/06 Collating Results.....................................................................................................39
08/06 Working on Report..................................................................................................39
09/06 Collecting Data: Mass.............................................................................................39
15/06 Working on Report..................................................................................................39
Table 1: Change in water basicity when reacting to metal (pH) with balanced chemical
equations.......................................................................................................................... 40
★1★
,★2★
,Abstract
Orthopaedic implants restore function and support damaged bones or replace missing joints
due to trauma defects, diseases, or abnormal congenital[1] development. Materials used in these
implants are selected based on biocompatibility, corrosion resistance, and mechanical
properties (Mohamed, 2016a).
The broadening of research into benefits of alternative metal orthopaedic implants reveal
potential improvements in both patient outcomes and technological furtherment. This
experiment aimed to investigate the reactivity of various metals (copper, zinc, and magnesium)
in water and sodium chloride solution at body temperature as a rudimentary in vitro simulation of
their compatibility in common procedural conditions in orthopaedics, i.e. sterilisation and
implantation. It was hypothesised that copper would be less reactive than zinc and magnesium
through knowledge of metal properties (Discussion, p.8), making it the most biocompatible.
Results measuring changes in pH and changes in mass (avg. loss% (Mg) = 2.66%; (Zn) =
0.660%; (Cu) = 0.00%, Fig.1) over 5 days showed that this hypothesis was correct (Mg > Zn >
Cu).
Sources of error were also identified as variations in surface area and temperature fluctuations,
which may have affected the experiment accuracy. Future research could focus on improving
sources of error and investigating supplementary metal alloys as biomaterials to eliminate risks
of corrosion, metal ion release, and inflammation and infection from reactive metals, etc.
Introduction
Metallic implants, known for their strength and durability, are commonly used for load-bearing[2]
orthopaedic prostheses (Mohamed, 2016b). However, recent research aims to cultivate and
incorporate unconventional metallic implants to improve patient outcomes as surgical metals
like stainless steel, cobalt-based alloys, and titanium alloys used in current implants can have
negative post-surgery effects on patients, including stress shielding[3], metal ion releases, and
toxicity (Tsakiris et al., 2021). It is important for metals used in orthopaedic procedures to exhibit
minimal reactivity with bodily fluids, including blood in the periosteum[4] as well as during
sterilisation.
To simulate this, copper, zinc, and magnesium were placed in contact with cold distilled water
and 0.154 mol L-1 sodium chloride solution to replicate standard salt contents in blood (0.9%).
Established observations of the reactivity series as demonstrated by Jackson (2014) sustains
the hypothesis that copper is less reactive than zinc, which is less reactive than magnesium.
Selection of Metals
● Currently commercialised magnesium alloys in orthopaedics include MAGNEZIX® (Mg-Y-
RE-Zr) or RESOMET™ (Mg-Ca) in bioabsorbable screws and pins (Kose, 2019). The main
advantage to this field involves magnesium’s special osteoconductive[5] properties,
dissolution in bodily fluids, and harmless corrosion products even in the case of hydrogen
emission (Hassan et al., 2022; Antoniac et al., 2022).
● Zinc has potential for bioabsorbable orthopaedic implants as it exhibits promising
biodegradation behaviour, already prevalent in medical treatments such as in ointments,
cream, powders, etc, which require non-reactiveness with bodily fluids (Su et al., 2023).
★3★
, ● Due to copper’s antibacterial properties, its promising uses in water, wound dressings, and
medical equipment to prevent infections are currently investigated. E.g. An ongoing study
on osteomyelitis[6] implants by the Royal College of Surgeons in Ireland combines copper
ions with bioactive glass and collagen, found to cause a 3.6-fold increase in bone
development (Ryan et al., 2019).
Figure 0.1: Applications of biodegradable magnesium Figure 0.2: (A) Osteosynthetic
implants: (a) cardiovascular stents; (b) screws for zinc alloy plate and screws, (D)
orthopaedic fixation; (c) biodegradable microclips; (d) Fixed mandibular bone
biodegradable orthopaedic implants; (e) wound-closing fractures immediately after
devices. (Bordbar-Khiaban et al., 2019) surgery. (Wang et al., 2019)
Aim
To investigate the reactivity and biocompatibility of various metals by simulating conditions in
orthopaedic procedures.
Prediction
Copper will be less reactive to cold water and NaCl solution than zinc and magnesium, and thus
more biocompatible in orthopaedic procedures.
★4★
