Injection Techniques in Orthopaedics John Ebnezar
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1Introduction to Injection Techniques
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INTRODUCTION

Injections have always fascinated me. I have seen many patients yearning for that one wonder shot into the arm or buttocks, which can revert a patient from the gloom and despair of ill health to the comfort of normal health. I have always wondered how this unpleasant painful prick can restore normalcy in a jiffy. It took me some years of experience to realize that it mainly acted as a morale booster kindling a feeling of well-being in the patient that more often than not that did the trick and not its actual therapeutic effects.
However, there is a small group that is averse to the painful discomfiture an injection provides. Children in particular jump out of their skins at the very mention of the word injection. While the child cries its lungs out on being pricked, the parents seen to believe that louder the cry of their child faster will the disease flee from their beloved! A doctor with an injection in his hand appear as a villain to the child while he appears as a Messiah to the parents. This is the magic of injection in the field of medicine.
 
ROLE OF INJECTION IN ORTHOPAEDICS
The routine intramuscular and intravenous injection do find a place in orthopaedics in treating the fractures, dislocations, injections, arthritis, tumours, etc. Through these routes an orthopaedician seeks to administer painkillers, anaesthetics, intravenous fluids, blood, antibiotics, etc. to help him combat the orthopaedic 4disorders. However in orthopaedics apart from these routine techniques there are a few specialized injection techniques quite peculiar and specific to orthopaedicrelated problems. Unlike the conventional injections, injections in orthopaedics can play a dual interesting role of diagnosis and treatment. This is what makes the injection in orthopaedics very special and interesting. It is a specialized skill that needs to be developed with lots of diligence and practice in the backdrop of sound bony anatomy and landmarks. Needless to say it is not everybody's cup of tea!
 
THE PURPOSE OF INJECTIONS IN ORTHOPAEDICS
 
The Diagnostic Role
Aspiration of the synovial fluid and diagnostic injections are the diagnostic techniques commonly employed in orthopaedics to make a diagnosis in specific cases.
  1. Diagnostic aspiration of the synovial fluid: Examination of the aspirated synovial fluid helps confirm the diagnosis of different types of arthritis and also helps identify whether the disease is inflammatory or noninflammatory.
  2. Diagnostic injection techniques: This helps to:
    • Identify the source of pain
    • Indicate the exact area of the problem
    • Sort out the confusion regarding the diagnosis
    • Confirm the diagnosis
    • Provides a helpful guide to the future course of therapeutic action.5
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Fig 1.1: Wound over the anterior aspect of the knee joint due to fall. This has led to the development of traumatic synovitis. Note the fullness in the suprapatellar pouch. Mark the superomedial margin of the knee
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Fig. 1.2: Push the patella laterally and insert the needle through the point marked
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Fig. 1.3: Aspiration of the synovial fluid through an 18-gauge needle
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Fig. 1.4: Aspiration continued and the aspirate appears straw coloured indicating synovitis
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Fig 1.5: Collection of the blood tinged synovial fluid in a kidney tray. This confirms the diagnosis of traumatic synovitis. This has both therapeutic (pain relieved) and diagnostic (cause detected) value
Materials used: It is a mixture of a local anaesthetic preferably a 2 per cent plain lignocaine and a few cc of normal saline. While the first one alleviates the existing pain while the latter heightens it. But both indicate the course of origin of the unpleasant pain and thus indirectly help in making a diagnosis.
 
Diagnostic Injection Techniques
These have a wide role in identifying the source of pain in some soft tissue conditions and in low-backache conditions. The disappearance of pain after injecting local anaesthetic drug into the facets, nerve roots, foramen, disc, etc helps 8clearly establish the source of pain and with it the correct diagnosis.
 
Therapeutic Injection Techniques in Orthopaedics
As in diagnosis, so in therapeutics, injection techniques consists of joint aspirations and specific injection techniques.
  1. Therapeutic joint aspirations: Therapeutic joint aspirations are sometimes necessary to remove blood, pus, large effusions, sinovial fluid, etc. (See Box).
  2. Therapeutic injections: A lot many orthopaedic conditions affecting different joints and parts of the body can be treated by injections.
 
INDICATIONS
Injection treatment techniques are useful in the following conditions:
  • Arthritis
  • Synovitis
  • Bursitis9
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Fig. 1.6: Swelling of the knee joint within 2 hours of the injury suggests hemarthrosis
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Fig. 1.7:
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Figs 1.7 and 1.8: The part is being painted with povidone-iodine
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Fig. 1.9: The part is draped with a sterile towel
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Fig. 1.10: Superolateral corner of the patella is marked with a sterile marker
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Fig. 1.11: Infiltration of the skin with 2 per cent plain local anaesthesia
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Fig. 1.12: No 18 needle is being introduced into the joint through the point marked
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Fig. 1.13: Aspiration of dark colored blood
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Fig. 1.14: Aspirated blood without fat globules indicating that the source of blood is from the torn ligaments and not from an intra-articular fracture within the knee
  • Tendinitis
  • Tenosynovitis
  • Nodules
  • Enthesopathies
  • Trigger points
  • Compression neuropathies like the compartmental syndrome, etc
  • Crystal-induced arthritis: Gout, pseudogout, etc.
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Contraindications
  • Overlying cellulitis
  • Severe coagulopathy
  • Anticoagulant therapy
  • Septic effusion
  • More than 3 injections per year in weight-bearing joints.
  • Lack of response after 2 to 4 injections
  • Bacteraemia
  • Unstable joints
  • Inaccesible joints
  • Joint prosthesis
  • Osteochondral fractures
  • Overlying soft tissue infections or dermatitis
When does injection treatment make its grand entry as treatment modality in the field of orthopaedics?
  • When peripheral joints are affected
  • When two or more joints are actively inflamed and other joints are controlled by drugs
  • In conditions mentioned previously
  • When routine conservative measures fail to relieve pain as in Tennis elbow, golfer's elbow, low-backache, osteoarthritis, etc.
 
ABOUT DRUGS
  • Long-acting steroid preparation: These are more useful in chronic diseases like osteoarthritis, rheumatoid arthritis, etc
  • Short-acting steroid preparation: These are useful in soft tissue lesions like trigger point conditions, etc.15
Note: If long-acting steroids are used for soft tissue lesions, it may cause atrophy of fat, subcutaneous tissue, skin, etc.
  • Dosage: For larger joints: 50 mg of hydrocortisone acetate,40 mg of methylprednisolone and 20 mg of triamcinolone acetate
  • For smaller joints half of these dose
  • In a large joint like the knee adequate amounts of fluid is used along with the steroid to prevent it from remaining in one place
 
 
Choice of a needle:
  • For very large effusions—19-gauge needle
  • For injections without aspiration and for smaller joints like the interphalangeal joints, etc—23-gauge needle
  • Widely used needles—23-gauge.
 
Materials Required for the Injection Techniques
  • For skin preparation 1% chlorhexidine in spirit or a weak iodine solution
  • A range of needles and syringes of different sizes
  • Specimen sterile bottles to collect the aspirates
  • Local anesthetics without adrenalin
  • Steroids: hydrocortisone acetate (20 mg/ml), methylprednisolone acetate (40 mg/ml) and triamcinolone hexachloride
  • Swab, dressings and gauge
  • Elastocrepe bandages
  • Saline to distend the joints
  • Forceps for removing the jammed needles.16
Note:
  • Strict asepsis or a non-touch technique and disposable syringes and needles are a must.
  • Single dose ampoules are usually preferred
  • Sterile towels, masks and gloves are often not required.
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Fig. 1.15: Showing various joints in the body where injection techniques can be practiced both for therapeutic and diagnostic purposes
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Fig. 1.16: Showing the materials required for injection in orthopaedics. Disposable syringes, 2 per cent lignocaine, steroid injection vials, sterile needles, etc
 
DO YOU KNOW THE MANTRAS FOR SUCCESS IN INJECTIONS?
  1. During the procedure
    • Want first time success? Well, carefully palpate the bone landmarks and surfaces before injecting
    • Mark the site of injection with a marker or a thumbnail mark
    • It is better to approach the joint from the extensor surface to prevent damage to the important neurovascular structures lying on the flexor aspects
    • For skin preparation liberally apply chlorhexidine solution in spirit or weak iodine solution
    • For prolonged procedures like arthrography use towels.18
    To minimize the pre- and post-injection discomfort do the following:
    • Infiltrate the skin with 1 to 2 per cent solution of lignocaine
    • A local anaesthetic spray
    • A quick insertion of the needle into the joint causes minimum pain. However, this requires practice and skill.
  2. About the patient
    • The patient should be relaxed because injection becomes difficult if the muscles are tensed
    • The best position is supine with the head supported over a pillow. This is the ideal position to treat a vasovagal attack if encountered
    • To position the limb correctly and to reassure the patient use the services of a nurse
    • The patients who are going to benefit are those with warm swollen joints and with stiffness in the morning
    • Those not likely to benefit are those with crepitus, severe X-ray changes or instability.
  3. Certain important precautions that needs to be observed for better results.
    • Do not give more than three injections in the same joint or area for fear of suppressing the inflammation and causing neuropathic joint due to the use of local anaesthetics
    • Maintain a gap of one month between the injections
    • Do not inject if there is a possibility of septic arthritis or sepsis elsewhere
    • Aspirate before the injection to confirm no vessel19
    • While injecting into the soft tissues, jam the needle tightly as the contents have to be injected with force
    • Warn the patient about the post-injection pain
    • Instruct the patient to use the joint carefully for 24 hours after the injection
    • The first injection is often the most successful
    • The response in smaller joints is better and long lasting than the larger joints
    • The maximum beneficial effects of an injection will be seen in the first few days itself
    • Do not inject directly into the vessels, nerves, tendons etc.
    • Avoid damaging the articular cartilage
    • Limit to one large joint per visit.
 
 
Do You Know the Reasons for Failure of the Injections?
  • Improper identification of the site
  • Improper penetration
  • Improper diagnosis
  • Improper technique
  • Improper drugs
  • Improper dosage
  • Improper person giving it.
 
Post-injection Advice and Follow-up
After the injection give the patients the following advice:
  • Post-injection, the joint may remain painful for 24 hours
  • The benefits of the injection may be seen several days later20
  • After the injection the joint needs to be rested for 1 to 2 days
  • Avoid sports for at least 5 days
  • No exercises for few days
  • No heat therapy immediately after the injection.
 
Complications
  • Post-injection flare (2-5%)
  • Steroid arthropathy (0-8%)
  • Tendon rupture (<1%)
  • Facial flushing (<1%)
  • Skin atrophy or depigmentations (<1%)
  • Iatrogenic infectious arthritis
  • Transient paraesis of injected extremity (rare)
  • Hypersensitivity reaction
  • Asymptomatic pericapsular calcification
  • Hyperglycaemia in diabetes mellitus patients
  • Acceleration of cartilage attrition
Before we begin let us try to get familiarized with certain basic requirements of drugs for injection techniques in the field of orthopaedics:
 
RECOMMENDED LOCAL ANAESTHETICS
 
Commonly Used Drugs
  1. Lignocaine also called lidocaine
    • Dose: 3 mg/kg
    • Onset of action: Quick
    • Duration of action: 1 to 2 hours.21
  2. Levobupivacaine
    • Dose: 4 mg/kg
    • Onset of action: Slow
    • Duration of action: 2 to 4 hours.
  3. Bupivacaine
    • Dose: 2 mg/kg
    • Onset of action: Slow
    • Duration of action: 2 to 4 hours.
  4. Ropivacaine
    • Dose: 4 mg/kg
    • Onset of action: Fast
    • Duration of action: 2 to 4 hours.
 
RECOMMENDED CORTICOSTEROID INJECTIONS
  1. Triamcinolone
    • Duration of action: 12 to 36 hours
    • Equivalent dosage: 4
    • Relative anti-inflammatory potency: 5
    • Relative mineralocorticoid potency: 0
  2. Methylprednisolone
    • Duration of action: 12 to 36 hours
    • Equivalent dosage: 4
    • Relative anti-inflammatory potency: 5
    • Relative mineralocorticoid potency: 0.5
  3. Dexamethasone
    • Duration of action: 48 hours
    • Equivalent dosage: 0.75
    • Relative anti-inflammatory potency: 25
    • Relative mineralocorticoid potency: 022
  4. Hydrocortisone
    • Duration of action: 12
    • Equivalent dosage: 20
    • Relative anti-inflammatory potency: 1
    • Relative mineralocorticoid potency: 2
Note: Triamcinolone diacetate injections are best used for the spine.
 
Well Known Side Effects of Corticosteroids
  1. General side effects
    • Arthropathy
    • Impaired glucose tolerance
    • Irregularity of the menstrual cycle
    • Myopathy and muscle wasting
    • Osteoporosis
    • Psychologic upset
    • Suppression of the adrenal function.
  2. Local side effects
    • Depigmentation of the skin
    • Atrophy of the subcutaneous tissue23
    • Infection
    • Rupture of the injected tendons.
 
RECOMMENDED NEEDLES
  1. Joint injection: Needle gauges 22-25 with length of 1.5 inches.
  2. Joint aspiration: Needle gauges 18-20 with length of 1.5 inches.
  3. Special circumstances: Spinal needle.
e.g.
  1. Obesity: interferes with joint or bursa access
  2. Trochanteric/bursitis.
 
RECOMMENDED NEUROLYTIC AGENTS
  • Aqueous phenol 6 per cent
  • 100 per cent alcohol diluted to 50 per cent
 
RECOMMENDED RESUSCITATION DRUGS
  1. Atropine
    • Recommended dosage: 0.2 to 0.4 mg
    • Indication: Bradycardia due to vagal dominance.
  2. Ephedrine
    • Recommended dosage: 5 to 10 mg
    • Indication: Hypotension due to sympathetic block.
  3. Lignocaine
    • Recommended dosage: 50 to 100 mg iv bolus
    • Indication: Ventricular arrhythmias.
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  4. Midazolam
    • Recommended dosage: 1 to 3 mg iv increments
    • Indication: Seizures due to local anaesthetics.
  5. Diazepam
    • Recommended dosage: 2.5 to 5 mg iv increments
    • Indication: Seizures due to local anaesthetics.
  6. Thiopental
    • Recommended dosage: 50 to 100 mg iv increments
    • Indication: Seizures due to local anaesthetics.
  7. Succinylcholine
    • Recommended dosage: 50 to 100 mg iv bolus
    • Indication: Muscle relaxation airway control.
Note: A full range of drugs necessary for ACLS (Advanced Cardiac Life Support) with prefilled syringes should be made available in the operating room.
 
RECOMENDED RESUSCITATION EQUIPMENT
  • Oxygen cylinders
  • Endotracheal tubes of different sizes
  • Magill's forceps
  • Full range—oro and nasopharangeal airways
  • Full range—laryngoscopes and blades
  • Full range masks and bags
  • Breathing system for positive pressure ventilation.
Now, let us try to know the injection procedures for individual joints and other conditions is a systematic manner.