It is possible that podiatrists just may utilize injection therapy more than any other physicians as we perform injections on numerous patients on a daily basis. Our unique knowledge of foot and ankle anatomy allows us to have complete precision when we do surgery or inject into or around anatomical structures. When athletes do not desire surgical care or it is not an option, injection therapy gives us another route to heal the patient.
Injections have such a profound ability to change the direction of tissue response. We can use injections to control, reduce or eradicate inflammation, or reduce the bulk of damaged tissues. We have injections to cause neurolysis and we can now utilize injections to revive the inflammatory cascade to allow the immune system to come to the rescue to repair torn, thickened or scarred tissue. The armamentarium of injection products and protocols we have in our toolbox is great.
Although there are certainly conditions that will benefit from our traditional corticosteroid injections, a steroid will work to its fullest capability on specific conditions. Therefore, one needs to use injections properly and judiciously at that tissue site. When physicians overutilize injections or use them for the wrong diagnosis, injections have their downsides.
Since corticosteroids work best to reduce inflammation, they work best in fluid filled structures, like ganglions or other cysts. They also can reduce tissue bulk in neuromas, fibromas or even keloid scars. In these circumstances, the downside of the potential atrophy of the tissue is actually the desired effect.
As clinicians, we use the “-itis” term too regularly and forget that probably most of our patients are not in the acute phase but rather more of a semi-chronic or chronically injured state. This will commonly be evident when a typical corticosteroid injection does not relieve the pain. If clinicians repeatedly continue down the same pathway and there is little or no response, one needs to direct the protocol immediately toward a “chronic” treatment regimen. When a corticosteroid injection is the only type of injection the doctor offers, then continuity of care changes because there are no more conservative options to offer and often, physicians then suggest a surgical route to the athlete.
Keys To Proper Diagnosis And Effective Treatment
Obtaining the proper diagnosis is imperative. I generally prefer diagnostic ultrasound. This test determines the true echotexture, which describes collagen alignment and thickness, and will often detect if any linear tearing or deficits are present, even if they are very small. Since this test can look at the structures in multiple planes, there are no limits of slicing parameters or limited planes of imaging as determined by magnetic resonance imaging (MRI) protocols.
Functional testing can determine the presence of joint laxity and whether capsular or ligamentous tissues have true, complete tears. When the results show the tissue is in a chronic state, it is very reasonable to understand why the steroid did not work as there are no acute inflammatory cells present. This understanding is why it is important to have more than one injection option, which will benefit the patient and the doctor, and allow quicker resolution.
I believe the future of soft tissue repair is really biologically based. If we can manipulate and accelerate the biology of healing and augment the mechanical strength of the tissue by inducing growth factors and inciting the inflammatory cascade, we are truly making a difference in the future structure of the tissue that is injured. Encouraging the tissue to remodel and lay down type I collagen is the goal here as long-term chronic “inflammation” results in a loss of function, production of other non-desirable collagen types and sometimes complete fibrosis. Here the physician should consider the use of different injection therapies that induce growth factors and resurge the inflammatory cascade to redirect tissue repair back into the proper direction (see “An Overview Of The Stages Of Wound Healing” at right)
Choosing From The Various Injection Therapies
Available injection therapies include prolotherapy, platelet rich plasma (PRP) injections and needling injections. All of these injection therapies promote the inflammatory cascade via infusion of growth factors, which will eventually induce new type I collagen production. When one introduces a needle into any tissue, it produces the “needle effect” or “puncture phenomenon,” creating local inflammation at the injection site. It causes irritation of nerve endings, gait control reactions and often influences distant components of segmental nerves by reflex stimulation. Inserting a needle into tissue also releases opioid peptides (endorphins and enkephalins) in the nervous system.
Prolotherapy. Prolotherapy rehabilitates an incompetent structure, such as a ligament or tendon, by inducing the proliferation of new cells. The solutions that are typically in use are a mix of dextrose solution, lidocaine and Sarapin (High Chemical Company). Dextrose is a corn extract, which is more hypertonic than blood and will not affect blood sugar issues in patients with diabetes. Sarapin is an extract of the pitcher plant, has no known side effects and accelerates the cellular particles into the tissue. Lidocaine gives immediate relief and confirms the location of the problem. If a patient is corn intolerant, one can use other agents, such as sodium morrhuate, an extract of cod liver oil. Zinc sulfate or a dextrose-glycerin-phenol solution called P2G are other options.
Prolotherapy is effective on any chronically damaged tissues. Physicians can administer the injections every four weeks with a total of three to six visits. Injections occur at the site of injury or chronic pain with the goal of strengthening the tissues by inciting the inflammation response and encouraging the collagen type 1 to form. Hackett’s original study on prolotherapy showed increases in strength and proliferation of the tissues at the fibro-osseous junctions in the rabbits that he sacrificed.1 Holistic physicians have used this technique since approximately the 1950s.
Platelet rich plasma. The PRP injections utilize a completely autologous system. After extraction of a small amount of the patient’s own blood and with a centrifuge process, the blood spins down, producing a fibrin matrix scaffold product. One can then inject this platelet rich fibrin matrix into the patient’s injured soft tissues.
Depending on the system used, the platelets and the numerous growth factors they induce will persist for varying days at the tissue site. This will incite the introduction of the proper cascade of events to occur to produce new healthy collagen. With this technique, one can use the protocol for injection or if the product goes through the centrifuge twice, physicians can suture the product into a wound, around a surgically repaired tendon or soft tissue structure. Many podiatric and orthopedic physicians are knowledgeable of this protocol, but may be limited in using the technique due to insurance reimbursement issues. Physicians can use PRP more than once in a particular area but cost may limit the exposure or usage for many patients.
Needling. This is my choice as needling is a general injection therapy that one can use for most tissues: ligaments, tendons, fascia or muscle, and with various solutions. Some physicians or physical therapists even do needling “dry.” The benefits to this technique are that costly solutions or products are not necessary, the office visits are quick, and insurance typically covers the traditional injection CPT codes.
I utilize a homeopathic medication that induces growth factors. Although it has some mild anti-inflammatory effects unlike corticosteroids, the medication will not dampen the immune system but rather incite the properly mediated cells to do their job. Depending on location/injury size, it is helpful to fan the injection throughout the damaged tissue. These injections can occur weekly or bimonthly in combination with other office treatments. In over 10 years of performing these injections, I have found that the optimal timing of tissue repair, which has had a nice correlation with patients’ decreasing symptoms, has typically been approximately 10 to 16 weeks with continual repair/strengthening of the tissues occurring even after the last injection.
“Biopuncture” is another simple needling injection technique. With this technique, the physician raises small wheals in a pattern all around the injured tissue. It is similar to “ringing the dragon,” an acupuncture technique that some physicians use. Raising small wheals or just depositing the medication in individual or specific acupressure or acupuncture points will also work well.
Percutaneous alcohol nerve sclerosing injection. Also known as alcohol sclerosing injection, this is another injection therapy that podiatric physicians may be under-using. It is an excellent injection therapy that one can use in lieu of surgical intervention, especially for athletes.
Physicians typically use percutaneous alcohol nerve sclerosing injection for web space neuromas. Hughes and colleagues in 2007 followed 101 patients in a study on alcohol injections for Morton’s neuromas.2 The author related that alcohol injections had a very high success rate in eradicating interdigital web space neurtic pain. Some other studies have shown upwards of 90 percent success rate.3 In the podiatric world, the nerve injection technique can be credited to Marvin D. Steinberg, DPM, and later Max Weisfeld, DPM, and G. Dock Dockery, DPM.4-6
In theory, the 4% Dehydrated Alcohol Injection (Akorn Pharmaceuticals) produces injury to tissue cells by Wallerian degeneration, dehydration and precipitation of protoplasm, thus casing nerve degeneration. Clinicians would typically perform the injections weekly and approximately three to seven injections may be needed. With each injection, the symptoms diminish.
Akorn Pharmaceuticals notes that “the injection of alcohol used for therapeutic neurolysis involves amounts too small to produce significant systemic effects of ethyl alcohol.”7 Furthermore, the company states that “Ninety to 98 percent of the product that enters the body is completely oxidized.” The complications are minimal or even rare, but some post-injection neuritis or lymphatic reactions can occur. I have only observed the post-injection neuritis a few times.
Having a variety of injection techniques in our toolbox is essential for the podiatric physician as we traditionally use many conservative treatments even in the busiest surgical practices. Improving conservative options for any practice improves patient satisfaction, especially when surgery is not an option. This can even be helpful for improving practice revenue when reduced surgical reimbursements are the norm. Most injections have rare or minimal complications, and almost any patient population can benefit.
When treating chronic conditions, it is imperative for physicians to control any abnormal edema with formal compression products, offload the tissues when appropriate, evaluate for any shoe gear issues and help realign any abnormal foot mechanics with custom orthoses. Any and all of the aforementioned injection protocols will work to their fullest when clinicians address all of these other aspects of patient care as well.
Additionally, relative rest is important for athletes as continued sport or other aggravating activity will most likely interrupt the proper healing cascade as I mentioned above.
Dr. Schoene is a triple board certified sports medicine podiatrist and a certified athletic trainer. She is a Fellow of the American Academy of Podiatric Sports Medicine and the American College of Foot and Ankle Surgeons.
1. Hackett GS. Prolotherapy in whiplash and low back pain. Postgrad Med. 1960; 27:214-19.
2. Hughes RJ, Ali K, Jones H, et al. Treatment of Morton’s neuroma with alcohol injection under sonographic guidance: follow-up of 101 cases. AJR Am J Roentgenol. 2007; 188(6):1535-9.
3. Fanucci E, Masala S, Fabiano S, et al. Treatment of intermetatarsal Morton’s neuroma with alcohol injection under US guide: 10-month follow-up. Eur Radiol. 2004; 14(3):514-518.
4. Steinberg MD. The use of vitamin B-12 in Morton’s neuralgia. J Am Podiatr Assoc. 1955;97(4):293-5.
5. Weisfeld M. Understanding porokeratosis plantaris discrete. J Am Podiatr Assoc. 1973;63(4):138-144.
6. Dockery GL. The treatment of intermetatarsal neuromas with 4% alcohol sclerosing injections. J Foot Ankle Surg. 1999;38(6):403-406.
7. Available at http://www.akorn.com/prod_detail.php?ndc=17478-503-05 .
Editor’s note: For related articles, see “Platelet Rich Plasma: Can It Have An Impact For Tendinosis And Plantar Fasciosis?” in the May 2009 issue of Podiatry Today, “When Injection Therapy Can Help Relieve Painful Lesions” in the June 2002 issue or the March 29, 2011 DPM Blog “Do You Inject The Plantar Fascia On The First Visit For Plantar Heel Pain?” by Doug Richie, Jr., DPM.