Background & Aims

Chronic knee pain is a prevalent condition worldwide. Knee osteoarthritis (OA) is one of the most common causes. Acording to worldwide estimates, it has a global prevalence of 16%(1) and an incidence of 203 per 10.000 person-years(1).
In Chile the prevalence of knee OA is 19% and the annual cost per musculoeskeletal pain is 1.387,2 millions of dollars, being knee OA 27.1% of that cost(2).

Different neurolysis techniques have been used for genicular nerve ablation, being
radiofrecuency ablation (RFA), chemical denervation using mainly phenol and alcohol between the most used, These techniques offer mixed results, and are possibly painful procedures for the patient.

In this context we decide to start using cryoablation, being less painfull than RFA and longer lasting than chemical alternatives.

Our goal is to provide an alternative in the management of chronic knee pain and implement this tecnique in our medium-complexity hospital in southern Chile.

Methods

Genicular nerve cryoablation was performed on 51 patients, totalling 63 knees, between July 2020 and April 2024.
We used the classic approach described by Choi el al, targeting the superior medial genicualr nerve (SMGN), superior lateral genicular nerve (SLGN) and inferior medial genicular nerve (IMGN) using a METRUM CRYOFLEX CRYO-S Painless device and sacroiliac joint (SIJ) Cryoprobe needles taking advantage of the curve tip and ablation area of 4.5 cm.
Patients were placed in a supine position with a pillow under the knee to produce 30° of flexion, cryoablation was made after a positive diagnostic echoguided genicular nerve block using 1 ml of 2% lidocaine, defined as 50% pain relief using numeric rating scale (NRS).

Cryoablation needles were guided by fluoroscopy at the targetet points, then motor nerve activity was excluded by testing at 2 Hz and 2 mA. After that a 2 min -78°C degrees freezing cycle per nerve was permormed.

Results

The results of the procedures were evaluated using an adaptation of the IKDS subjective knee form, objectiveing the perceived pain during various activities of daily living, before the procedure and at the first and second month post-procedure, through a telephone survey

Out of the 51 patients who underwent the procedure, 10 of them completed the survey. Among those patients, 7 patients (70%) experienced a decrease of more than 50% in pain score at the first month, and 6 of them maintained that decrease at the second month. On the other hand, out of the 10 patients, 3 experienced an increase of over 30% in pain score at the first month, and 4 experienced it at the second month

Conclusions

With this study, we aim to present our initial experience in the use of cryoablation technique on genicular nerves for multimodal management of chronic knee pain, while also documenting its analgesic effects in the medium and long term.

Our results show a significant loss to follow-up of patients, primarily due to unanswered phone calls (30 out of 51 patients) and the death of one of them for causes not related to chronic knee pain.

These results highlight the need to improve our post-procedure monitoring, find a validated score that allows for better tabulation of results, and continue studying and using interventional techniques to aid in the management of chronic knee pain in our population

References

1.Blümel, Juan E., Aedo, Sócrates, Arteaga, Eugenio, Vallejo, María S., & Chedraui, Peter. (2022). Factores de riesgo de artrosis de rodilla, cadera o ambas en mujeres chilenas de mediana edad: un estudio de cohorte de tres décadas. Revista médica de Chile, 150(1), 46-53. https://dx.doi.org/10.4067/S0034-98872022000100046
2.Pacheco D, Vizcarra G, Castillo V, Fuentealba C,Alvarez M, Ballesteros F. Perfil de la consulta reumatológica. Comparación entre un policlínico de atención primaria vs uno de reumatología. Revista Chilena de Reumatología 1997; 13: 101.
3.Choi W-J, Hwang S-J, Song J-G, et al. Radiofrequency treatment relieves chronic knee osteoarthritis pain: a double-blind randomized controlled trial. Pain. 2011;152(3):481–7. https://doi.org/10.1016/j.pain.2010.09.029
4.Panagopoulos A, Tsiplakos P, Katsanos K, Antzoulas P, Lakoumentas J. Cooled radiofrequency ablation versus cryoneurolysis of the genicular nerves for the symptomatic pain management in knee osteoarthritis: a study protocol of a prospective, randomized, single-blinded clinical trial. J Orthop Surg Res. 2023 Apr 12;18(1):295. doi: 10.1186/s13018-023-03737-1. PMID: 37041607; PMCID: PMC10091842.

Presenting Author

German Acuña

Poster Authors

German Acuna Game

MD

Hospital Traumatologico de Concepcion CHILE

Lead Author

Francisco Bolbaran MD

Hospital Traumatologico de Concepcion CHILE

Lead Author

Oscar Paredes MD

Hospital Traumatologico de Concepción CHILE

Lead Author

Jose Ibarra

Hospital de Lirquen

Lead Author

Anibal Elgueta MD

Hospital Traumatologico de Concepciom

Lead Author

Juan Cerda MD

Universidad de Concepcion Facultad de Medicina

Lead Author

Topics

  • Treatment/Management: Interventional Therapies – Ablation Techniques