Knee Pain: Pain Patterns of Myofascial Pain Syndrome and Degenerative Arthritis

OBJECTIVE: To evaluate the pain patterns of patients with osteoarthritis (OA) of the knee. METHOD: Forty-four patients (mean age 56.1 years) with pain around the knee who met the Simons' criteria for myofascial pain syndrome (MPS). Patients drew in their pain areas on a pain drawing diagram. The pain areas were input into the Pain Chart System (PCS) software program for analysis. Physical examination, trigger point injection, and exercises for knee muscles were performed. Oral analgesics were not prescribed. RESULTS: MPS was clinically diagnosed in all 44 patients. Radiologic examination revealed degenerative changes in 49 knees. Pain patterns detected by the PCS revealed pain patterns compatible with myofascial trigger point in the vastus medialis in 37 cases, rectus femoris in 32 cases, adductor longus in 5 cases, sartorius in 2 cases, vastus lateralis in 1 case, and the popliteus in 1 case. Following treatment, 36 of the 44 patients experienced pain relief. CONCLUSION: Degenerative changes of the joint seem not to be cause of the knee joint pain. Instead, pain relief following MPS treatment indicates the cause of knee pain as MPS. We recommend that the first step in the treatment for knee pain include recognition and treatment of MPS before applying invasive treatment.

Chronic Myofascial Pain Syndrome and Postherpetic Neuralgia

Postherpetic neuralgia(PHN) is a common complication of herpes zoster and one of most common intractable conditions in pain clinics. The PHN is defined solely by the persistence of pain after the herpes zoster. There has been no known pathophysiology for the PHN and the role of scars, local muscles, tendons and ligaments has not been addressed. The characteristics, duration, and location of the referred pain were evaluated along with the electromyographic(EMG) examination of involved muscles. Then treatment was given under the concept of a myofascial pain syndrome till the pain was completely resolved. Most of the patients with acute or chronic pain were relieved from the pain. This study revealed a practical and important new concept on herpes zoster related pains. In some cases of herpes zoster, acute herpes zoster seems to be an initiating factor to form an acute trigger point in the muscles of the related area. And uncomplicated trigger points neglected in an acute stage become chronic intractable problems, when they were neglected. In conclusion, myofascial pain syndrome should be taken into account when a postherpetic neuralgia is diagnosed. The recognition of this possible relationship between PHN and myofascial pain syndrome and an early proper care can greatly reduce the suffering of patents from chronic pain.