Common Injections in Sports Medicine: General Principles and Specific Techniques
Christopher J. Lutrzykowski
Francis G. O’Connor
Thad Barkdull
INTRODUCTION
Injections are a common intervention provided by sports clinicians. Injections can be both diagnostic and therapeutic. If delivered properly and with sound indications, injections can be very rewarding for both the patient and the provider.
This chapter details the indications, benefits, risks, and technique for administering common injections in sports medicine. These injections, while in most cases simple to administer, should be done only after proper training and appropriate supervision. Most injections are simple to learn (see one, do one, teach one); judgment on their use, however, takes time and effort to acquire.
INDICATIONS
Injections/aspirations are indicated for both diagnosis and therapy.
Diagnosis:
□ Synovial fluid analysis to rule out infection, traumatic, rheumatic, or crystal-induced etiology (Table 74.1)
□ To perform a therapeutic trial to differentiate various etiologies
□ Imaging studies
□ Synovial biopsy
Therapy:
□ To remove tense effusions to relieve pain and improve function
□ To remove blood or pus from a joint
□ For injection of steroids and other intra-articular therapies
□ For therapeutic lavage of joints
Risks/Complications (58) (Table 74.2)
Infection (9,37,60): The risk of postinjection infection is extremely rare, on the order of one infection per 3,000-50,000 injections when sterile technique is used. Staphylococcus aureus is the most common organism involved, with recent reports also implicating methicillin-resistant S. aureus (MRSA).
Tendon rupture (29): Collagen atrophy and tendon rupture are rare but have been described in the literature. Injections into tendons should be avoided. In addition, corticosteroid injections into the synovial sheath or peritendinous region of major weight-bearing tendons (Achilles, patellar, and plantar fascia) should be done with extreme caution, and the athlete should be protected from weight-bearing exercise for a period of 2-4 weeks.
Postinjection flare: This entity is seen in 2%-10% of patients. In this setting, the patient develops a flare of pain in the immediate 6- to 12-hour period after an injection. The etiology for this reaction is thought to be secondary to a local reaction to the microcrystalline steroid suspension and is generally self-limited. The postinjection flare has also been attributed to the preservative that accompanies the anesthetic. This complication may be treated with ice, activity modification, and a short course of a nonsteroidal anti-inflammatory drug (NSAID). Patients with pain beyond 36 hours should be evaluated for a septic joint.
Skin atrophy/depigmentation/hyperpigmentation: When local steroid is applied too close to the surface of the skin, local atrophy and depigmentation/hyperpigmentation can occur. These changes may be irreversible.
Hyperglycemia: In some diabetics, there may be short-term difficulties with glycemic control secondary to the local absorption of corticosteroid. This effect has been rarely reported and may be overstated (53).
Cartilage degeneration: Traditional teaching limits injections into a weight-bearing joint to no more than three injections per year, because there is some concern about weakening articular cartilage or frank chondrotoxicity from
studies on postoperative bupivacaine continuous drips (18,44,58). Recent studies indicate that more frequent injections are well tolerated, particularly when used in a disease-specific manner (54). Please see later section on use of anesthetics.
Table 74.1 Classification of Synovial Fluid
Classification
Appearance
WBC
PMNs(%)
Crystals
Culture
Normal
Clear to straw colored
< 150
< 25
None
Negative
Noninflammatory
Yellow
< 3,000
< 30
None
Negative
Inflammatory
Yellow or cloudy
3,000-75,000
> 50
None
Negative
Infectious
Yellow or purulent
50,000-200,000
> 90
None
Positive
Crystal-induced
Cloudy, turbid
500-200,00
< 90
Yes
Negative
Hemorrhagic
Red-brown
50-10,000
< 50
None
Negative
PMNs, polymorphonuclear leukocytes; WBC, white blood cell.
SOURCE: O’Connell TX. Interpreting tests from joint aspirates. In: Phenninger JL, editor. The Clinics Atlas of Office Procedures — Joint Injection Techniques. Vol. 5 (no. 4). Philadelphia (PA): WB Saunders Company; 2002.
Intravascular injection
Traumatic injection: Possible to cause a pneumothorax and damage articular cartilage, local nerves, or soft tissue structures
Vasovagal reactions
Facial flushing (10): Up to 15% and described mostly in women
Intramuscular injection
CONTRAINDICATIONS (54)
Cellulitis or broken skin over the needle entry site would increase the risk for infection.
Table 74.2 Common Adverse Outcomes
Complication
Estimated Incidence (%)
Postinjection flare
2-10
Steroid arthropathy
0.8
Tendon rupture
< 1
Facial flushing
< 1
Skin atrophy, depigmentation
< 1
Iatrogenic infectious arthritis
< 0.001-0.072
Transient paresis of injected extremity
Rare
Hypersensitivity reaction
Rare
Asymptomatic pericapsular calcification
43
Acceleration of cartilage attrition
Unknown
SOURCE: Gray RG, Gottleib NL. Intra-articular corticosteroids. An updated assessment. Clin Orthop Relat Res. 1983;(177):253-63.
Unstable coagulopathy
Intra-articular fractures are a contraindication to a corticosteroid injection.
Septic effusion of a bursa or a periarticular structure
Lack of response to prior injections
More than three prior injections in the last year to a weight-bearing joint
Inaccessible joints, e.g., hip, spine, sternoclavicular (62), and sacroiliac joints
Joint prostheses — relative contraindication
Known hypersensitivity to any component of the injection
GENERAL PRINCIPLES (38,63)
Consent: Because there are inherent risks and complications associated with corticosteroid injections, informed consent should be obtained, witnessed, and documented.
Equipment: Most injections are performed using an alcohol, chlorhexidine, or povidone-iodine wipe; some authors recommend a sterile scrub before injecting into a large joint (9,54). Sterile versus nonsterile gloves are another area of controversy; as a rule, the authors teach that sterile gloves are used for joints and nonsterile gloves may be used for soft tissue structures. Some advocate sterile gloves for all injections, whereas others prefer using the one sterile glove technique. In this technique, the physician wears the sterile glove on the noninjecting hand to ensure proper positioning after the local preparation. Finally, the “sterile no touch” technique may be employed as well, with only the needle touching the patient after preparation. Other equipment includes the following:
Povidone-iodine wipes and/or alcohol wipes
Sterile or nonsterile gloves
Sterile drapes: optional
21- to 27-gauge 1.5-inches needles for injection
18- to 20-gauge needles for aspirations
1- to 10-cc syringes for injections
3- to 50-cc syringes for aspirations
Ethyl chloride surface coolant
1% lidocaine
0.5% bupivacaine
2 × 2 gauze sponges
Small dressings such as Band-Aids
Access to equipment to treat severe allergic reactions: oxygen; epinephrine 1:1,000; Benadryl 25-50 mg intramural (IM); advanced cardiac life support (ACLS) equipment
Anesthesia: The three main uses of anesthesia include diminishing pain, aiding in diagnosis, and providing a volume for corticosteroid injections. Although there are many local anesthetics, the two most commonly used are the amide compounds lidocaine and bupivacaine.
Recent studies have indicated evidence of chondrolysis in postoperative patients treated with continuous intraarticular bupivacaine (3,47). Because no minimum volume has been described, cautious use of intra-articular anesthetic is recommended until this risk has been clearly defined.
Lidocaine (Xylocaine) is available commercially as a 0.5%-2% concentration. The most commonly used concentration is 1%; 2% may be used in small areas where a small volume is required. Time from injection to onset of effect is 1-2 minutes, with duration of action of approximately 1-2 hours. The upper limit of dosing is 10 mL for 2% and 20 mL for 1%; above these levels, side effects can be expected.
Bupivacaine (Marcaine) is available commercially in 0.25%-0.5% concentrations. Time from injection to onset of effect is 5-30 minutes, with duration of action of approximately 8 hours. The upper limit of dosing is 30 mL for 0.5% and 60 mL for 0.25%; above these levels, side effects can be expected.
Table 74.3 Relative Potencies and Solubilities of Corticosteroids
Corticosteroid
Relative Anti-Inflammatory Potency
Equivalent Dose(mg)
Solubility
Concentration (mg · mL−1)
Short-acting
Cortisone
0.8
25
NA
25, 50
Hydrocortisone
1
20
0.002
25
Intermediate-acting
Triamcinolone
5
4
0.0002
20
Hexacetonide
Methylprednisolone
5
4
0.001
20, 40, 80
Long-acting
Dexamethasone
25
0.6
0.01
4, 8
Sodium phosphate
Betamethasone
25
0.6
NA
6
NA, not applicable.
SOURCE: Genovese MC. Joint and soft tissue injection: a useful adjuvant to systemic and local treatment. Postgrad Med. 1998;103(2):125-34.
Side effects including anaphylaxis can occur; resuscitation equipment should be available.
An alternative to a local anesthetic injection is topical ethyl chloride. When used, however, spray lightly to avoid cold injury and secondary skin changes.
It is recommended to draw the anesthetic prior to the corticosteroid with multiuse vials to limit anesthetic contamination by the steroid (“clear to cloudy”).
Corticosteroids (54): Corticosteroids are commonly used in musculoskeletal medicine. The corticosteroid treats the local inflammatory response and not the clinical problem. Steroids have both mineralocorticoid and glucocorticoid effects. The mineralocorticoid effects modify salt and water balance, while the glucocorticoid effect suppresses the inflammatory response. The ideal choice is to use a medication that maximizes the anti-inflammatory effect. Steroids also differ in their solubilities, potencies, and duration of action (Table 74.3). The duration of the effect is thought to vary inversely with the drug’s solubility. Shorter acting agents tend to have a lower incidence of postinjection flare. In general, higher solubility agents (e.g., betamethasone [Celestone], dexamethasone, and methylprednisolone) tend to be better for soft tissues, whereas lower solubility agents (e.g., triamcinolone hexacetonide) tend to favor joint injections. Selected dosing is found in Table 74.4.
Alternative injections such as platelet-rich plasma, autologous blood, and prolotherapy are discussed elsewhere in this text.
Technique
Patient: The patient should be in a comfortable position, preferably sitting or lying down. The most important
aspect of the patient’s position, however, is that the physician injecting is comfortable and can easily identify anatomic landmarks and administer the injection.
Table 74.4 Recommended Corticosteroid and Lidocaine Dosages for Injections
Site of Injection
Dose of 1% Lidocaine (mL)
Dose of Triamcinolone (mg)
Dose of Betamethasone (mg)
de Quervain
1-2
40
6
Carpal tunnel
0.5-1
40
6
Trigger finger
1
20
3
Tennis elbow
0.5-1
40
6
Subacromial space
6-8
40
6
Glenohumeral
6-8
40-60
6-9
Acromioclavicular
1-2
40
6
Plantar fascia
1-2
40
6
Anserine bursa
2-3
40
6
Trochanteric bursa
4-5
40-60
6-9
Intra-articular knee
4-6
40-60
6-9
Morton neuroma
1-2
20-40
3-6
Myofascial
1-2
NA
NA
Iliotibial band
1-2
20-40
3-6
Ankle
2-3
40
6
NA, not applicable.
SOURCE: Stankus SJ. Inflammation and the role of anti-inflammatory medications. In: Lillegard WA, Butcher JD, Rucker KS, editors. Handbook of Sports Medicine. 2nd ed. Boston (MA): Butterworth-Heinemann; 1999.
Be prepared: Have all your equipment ready so that you can move quickly. Have your combination of steroid and anesthetic already drawn up and ready to go. Remember to use separate needles for drawing up different agents.
Identify structure: Put the skin under traction and identify anatomic landmarks. If needed, the skin can be marked with a fingernail, a retracted end of a ballpoint pen, or ink.
Aseptic technique: The area may be cleansed with alcohol, povidone, or betadine using nonsterile gloves. When entering a joint, a sterile prep may be used, but swabbing with betadine or other suitable antimicrobial prep is common practice.Related posts:
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