Acupuncture Versus Non-Steroidal Anti-Inflammatory Drugs for Treatment of Chondromalacia Patellae: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Chondromalacia patellae is a condition that causes pain behind the kneecap due to softening and deterioration of the cartilage. It affects approximately 25% of the general population and is even more common in athletes. Symptoms include retropatellar pain, joint swelling, crepitus, and quadriceps weakness, frequently aggravated by activities such as climbing stairs or sitting for prolonged periods. This systematic review and meta-analysis aimed to evaluate the efficacy of acupuncture compared with nonsteroidal anti-inflammatory drugs (NSAIDs) in the treatment of this condition.

The researchers performed a comprehensive search in eight databases through June 2016, including both Western databases (PubMed, EMBASE, CENTRAL) and Chinese databases (CNKI, Wanfang, VIP, CBM). Initially, 406 studies were identified, of which only 7 randomized clinical trials met the strict inclusion criteria. All included studies were conducted by Chinese researchers and published between 2006 and 2015, involving 707 participants aged 20 to 79 years. Study methodology varied, including electroacupuncture, heated needles, silver needles, and modified needling techniques.

The most frequently used acupuncture points were EX-LE4 and EX-LE5, located in the knee region. In the control group, the anti-inflammatory drugs used included diclofenac sodium, meloxicam, and celecoxib, with treatment duration ranging from 2 to 6 weeks. The meta-analysis results demonstrated significant superiority of acupuncture over NSAIDs. For clinical efficacy, analyzed in 5 studies with 465 patients, acupuncture showed a risk ratio of 2.57 (95% CI: 2.02-3.27), indicating that patients treated with acupuncture had more than twice the probability of obtaining clinical improvement.

As for pain scores, evaluated in 2 studies with 242 patients through the visual analog scale, acupuncture demonstrated superior pain reduction with a mean difference of -1.49 points (95% CI: -2.37 to -0.62). The proposed mechanisms for the efficacy of acupuncture include multiple pathways of action. According to traditional Chinese medicine theory, chondromalacia patellae is classified as 'Bi syndrome,' characterized by muscle tension on a basis of deficient 'upright Qi.' Stimulation of the EX-LE4 and EX-LE5 acupoints with heated needles would help strengthen muscles and bones, warm the channels, disperse cold, and promote blood circulation. From a biomedical standpoint, acupuncture stimulates afferent fibers that coordinate somatomotor and autonomic responses, leading to pain relief.

Electroacupuncture blocks pain by activating bioactive mechanisms including endogenous opioids, which desensitize peripheral nociceptors and reduce pro-inflammatory cytokines both peripherally and in the spinal cord. Additionally, acupuncture promotes blood and synovial fluid circulation in the joint, strengthening articular cartilage nutrition. An important aspect was the absence of reported adverse events in the acupuncture studies, contrasting with the known side effects of NSAIDs, such as gastrointestinal, cardiovascular, and renal problems. Only one study performed detailed safety analysis, showing that blood, urine, stool tests, and hepatic and renal functions remained normal after acupuncture treatment.

However, the results should be interpreted with caution due to the low methodological quality of the included studies. All studies presented high risk of bias in multiple domains. Only 2 studies reported adequate methods of random sequence generation, none provided information on allocation concealment, and it was not possible to blind patients and therapists due to the nature of the interventions. The absence of placebo groups and the impossibility of blinding may have led to overestimation of acupuncture effects.

Funnel plot analysis revealed asymmetry, suggesting publication bias. Heterogeneity among studies was also observed, particularly in pain scores. For clinical practice, these findings suggest that acupuncture can be a valid alternative to NSAIDs for patients with chondromalacia patellae, especially considering the superior safety profile. Acupuncture may be particularly useful for patients who do not tolerate NSAIDs or prefer non-pharmacologic approaches.

The combination with rehabilitation exercises, as used in some studies, may potentiate the therapeutic benefits.