Efficacy of Genicular Nerve Block in Patients with Osteoarthritis: A Comparative Study with and without Fluoroscopy Assistance

Abstract

Objective To compare the efficacy of fluoroscopy as an auxiliary method in genicular nerve block (GNB) with block guidance by anatomical parameters, without imaging aid, in reducing pain. Methods A total of 23 patients underwent fluoroscopy-guided or anatomical parameter-based GNBs. We applied the Western Ontario and McMaster Universities' Osteoarthritis Index (WOMAC) and the Visual Analog Scale (VAS) for pain at 6 time points (preblock, and after 1 hour, 24 hours, 7 days, 28 days, and 90 days). Results The mean age of the sample was of 64.5 ± 4.8 years, and the mean Body Mass Index (BMI), of 31.4 ± 6.1 Kg/m ² ; 16 subjects (69.6%) were women. The WOMAC pain subscale showed a significant reduction ( p < 0.05) in pain in both groups at all time points. This reduction was greater after 1 hour in both groups, with rates if 64.3% and 64.6% in the fluoroscopy and anatomical parameters groups respectively, with no significant difference. At the end of 90 days, the pain reduction rates were of 35.7% and 44.6% in the fluoroscopy and anatomical parameter groups respectively. The VAS also showed a significant reduction ( p < 0.05) in pain in both groups at all times. The reduction was more significant after 1 hour: 78.0% in the fluoroscopy group and 82.2% in the anatomical parameter group, with no significant difference. At the end of 90 days, the pain reduction was of in the fluoroscopy group 36.5% and of 24.6% in the anatomical parameters group. Conclusion The GNBs guided by fluoroscopy or by anatomical parameters alone were equally effective in terms of magnitude and duration of pain relief.

Keywords: fluoroscopy; nerve block; osteoarthritis, knee; pain; visual analog pain scale.

Fig. 1

Anteroposterior radiograph demonstrating the reference points at fluoroscopy. Abbreviations: SL, superolateral; SM, superomedial; IM, inferomedial.

Fig. 2

( A ) Anterior view with lines drawn through the head of the fibula; ( B ) oblique view showing the line drawn 4 cm above the femoral epicondyle.

Fig. 3

Graphical representation of the variation in the mean score on the pain subscale of the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) at the different evaluation times. Note: The mean pos-block scores are statistically lower than the mean preblock score for all evaluation times ( p  < 0.05). Abbreviation: GNB, genicular nerve block.

Fig. 4

Graphical representation of the variation in the mean score on the visual analog scale (VAS) for pain at the different evaluation times. Note: The mean postblock scores are statistically lower when compared to the mean preblock score for all assessment times ( p  < 0.05). Abbreviation: GNB, genicular nerve block.

Fig. 1

Radiografia anteroposterior demonstrando os pontos de referência a serem buscados com auxílio da fluoroscopia. Abreviaturas: SL, superolateral; SM, superomedial; IM, inferomedial.

Fig. 2

( A ) Visão anterior com as linhas traçadas através da cabeça da fíbula; ( B ) visão obliqua evidenciando a linha traçada 4 cm acima do epicôndilo femoral.

Fig. 3

Representação gráfica da variação da média da pontuação na subescala de dor do Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) nos diferentes momentos de avaliação. Nota: As médias das pontuações pós-bloqueio são estatisticamente menores quando comparadas com a média da pontuação pré-bloqueio para todos os momentos de avaliação ( p  < 0,05).

Fig. 4

Representação gráfica da variação da pontuação média na escala visual analógica de dor nos diferentes momentos de avaliação. Nota: As médias das pontuações pós-bloqueio são estatisticamente menores quando comparadas com a média da pontuação pré-bloqueio para todos os momentos de avaliação ( p  < 0,05).