Temperature-Mediated Neural Interventions in Knee Osteoarthritis: a Review of Cryoneurolysis and Cooled Radiofrequency Ablation with Ultrasound Guidance.

PURPOSE OF REVIEW: Knee osteoarthritis is a debilitating chronic disease affecting nearly half of the world's population at some point in their lives. Treatment of pain and loss of function associated with this disease has been limited. In this review, we seek to explore how neural interventions with ultrasound guidance may be an emerging option for non-pharmacologic pain relief in patients with knee osteoarthritis. RECENT FINDINGS: Cryoneurolysis techniques have been demonstrated to provide pain relief out to 150 days post-treatment in knee osteoarthritis in select individuals. There have also been studies of cryoneurolysis pre-operatively to total knee replacement providing reduced pain, reduced opioid use post-operatively, and shorter hospital length of stay. Cooled radiofrequency ablation (CRFA) has been demonstrated to significantly reduce pain, improve functionality, and reduce pharmacologic needs in knee osteoarthritis out to 2 years. Both interventions appear to have increased accuracy with ultrasound, and CRFA appears to be associated with improved patient outcomes. The research demonstrates the efficacy of both cryoneurolysis and cooled radiofrequency ablation in the treatment of knee osteoarthritis. Ultrasound guidance in neurolysis provides an additional tool with real-time, high-accuracy nerve localization. These therapies should be considered for certain patients to assist in pain management in the non-operative and post-operative phase of knee osteoarthritis management. Further research is needed to further define the long-term effects and the long-term utility of the techniques in knee pain.

Infrapatellar Branch of the Saphenous Nerve: Therapeutic Approaches to Chronic Knee Pain.

PURPOSE OF REVIEW: The infrapatellar branch of the saphenous nerve (IPS) is an under-investigated nerve that can be a source of chronic knee pain. This literature review aims to deliver an up-to-date review of chronic pain transmitted via the IPS along with therapeutic approaches available for pain refractory to conservative measures. RECENT FINDINGS: Knee pain transmitted via the IPS can arise from several etiologies. Damage to the IPS is often iatrogenic and develops following total knee arthroplasty, anterior cruciate ligament reconstruction, and other knee surgical procedures. Other causes of IPS-derived pain include entrapment of the nerve, neuromas, Schwannomas, and pain from knee osteoarthritis transmitted through the IPS.This article investigated therapeutic approaches to pain derived from the IPS. Common approaches included radiofrequency ablation, neuroma excisions, Schwannoma excision, nerve blocks, surgical exploration, surgical release of an entrapped nerve, cryoablation, and peripheral nerve stimulation. Pain scores, duration of pain relief, adverse events, and secondary outcomes were all included in this review. A subset of the patient population experiences chronic pain deriving from the IPS that is refractory to conservative treatment measures. This review aims to evaluate the etiologies and therapeutic approaches for chronic pain arising from the IPS refractory to conservative treatments.

Effectiveness of the Cooled Radiofrequency Ablation of Genicular Nerves in Patients with Chronic Knee Pain Due to Osteoarthritis: A Double-Blind, Randomized, Controlled Study.

Background: Increasing evidence supporting the clinical effectiveness of cooled radiofrequency ablation (RFA) therapy for genicular nerves in patients with chronic knee osteoarthritis (OA) exists. However, no study has been conducted to eliminate the potential influence of a placebo effect associated with this procedure. Therefore, we evaluated the efficacy of cooled RFA compared with a sham procedure in patients with painful knees due to OA. Methods: In this double-blind, randomized, controlled study, participants were randomly assigned to receive cooled RFA of the knee (cooled RFA group, n = 20) or a sham procedure (sham group, n = 20). The primary outcome was the proportion of successful responders at the three-month follow-up. The secondary outcomes were successful responders at one and six months; pain intensity of the knee; functional status; medication; and satisfaction at one, three, and six months after the procedures. Results: For the primary outcome, the successful responder rate was significantly higher in the cooled RFA group (76.5%) than in the sham group (33.3%) (p = 0.018). For the secondary outcome, more successful responders were observed in the cooled RFA group than in the sham group at one and six months after the procedure (p = 0.041 and 0.007, respectively). The decreased knee pain intensity was maintained throughout the six-month follow-up period in the cooled RFA group. No differences were observed in functional status, medication change, or satisfaction in both groups. Conclusions: The cooled RFA of genicular nerves offers significant pain relief and surpasses the effects attributable to a placebo.

Anatomical Variation of Infrapatellar Innervation Determines Clinical Risk of Infrapatellar Neuropathy.

BACKGROUND: Infrapatellar neuropathy arises from traumatic, iatrogenic, or compression injury to the infrapatellar branch (IB) of the saphenous nerve. The risk of infrapatellar neuropathy has been shown to depend on the IB's anatomical course. The infrapatellar branch of the saphenous nerve (ISBN) has been discovered to take varying courses, and the IB can emerge directly from the femoral nerve. The variety of the IBSN's courses and the prevalence of cases involving the infrapatellar branch of the femoral nerve (IBFN) call the uniform IB course described in textbooks into question. OBJECTIVES: In this study, we aim to identify sites of IB emergence and their anatomical relations and evaluate them for their risk of neuropathy. STUDY DESIGN: The study is an anatomical prospective pilot study. SETTING: The setting is a single-center cadaveric study performed at the anatomical institute of the Medical University of Vienna. METHODS: Twenty-two anatomical specimens were evaluated for the relationship of their IBs to anatomical risk sites. The subsartorial course, distal sartorial penetration, and the crossing of the medial femoral epicondyle were assessed. The measurements and relations of the IB were determined with callipers and assessed by computational modelling. RESULTS: Nine IBs originated from the saphenous nerve, 11 originated from the femoral nerve, and 2 originated from both. The subsartorial course was most frequent in IBs of saphenous origin. Penetrating and profound distal sartorial relations correlated moderately with emergence type and were highest in the saphenous group. The crossing of the medial femoral epicondyle was the most common relation of IBs that emerged femorally. LIMITATIONS: The study's limitations were the low number of cadavers to examine and the confining of the exploration of knee extension to anatomical specimens that restricted an inferential analysis. CONCLUSION: Infrapatellar innervation can emerge from the saphenous nerve, the femoral nerve, or a combination of both, and the origin of the innervation determines the clinical risk for infrapatellar neuropathy. While innervation from the IBSN may lead to compression at the subsartorial course, distal sartorial penetration, and the crossing of the medial femoral epicondyle, innervation from the IBFN carries reduced anatomical risk for infrapatellar neuropathy.

Effectiveness of Radiofrequency Ablation of the Genicular Nerves of the Knee for the Management of Intractable Pain from Knee Osteoarthritis.

BACKGROUND: The knee joint is one of the most common diseases in elderly individuals. This is a progressive and debilitating condition. The purpose of knee osteoarthritis treatment is to manage pain, increase mobility, and improve the quality of life. OBJECTIVES: This study evaluated the therapeutic effect of radiofrequency thermocoagulation (RFTC) on the genicular nerves in patients with intractable pain due to knee osteoarthritis, as well as its effects on pain severity and magnetic resonance imaging (MRI) findings. STUDY DESIGN: A prospective outcome study. SETTING: The outpatient clinic of a single academic medical center. METHODS: We conducted a prospective study. Fifty consecutive patients with intractable knee pain due to osteoarthritis were enrolled and underwent ultrasound (US)-guided RFTC of the genicular nerves (medial superior genicular nerve, medial inferior genicular nerve, and lateral superior genicular nerve). Pain severity was measured using the Numeric Rating Scale (NRS), and knee osteoarthritis-associated symptoms were evaluated using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) at pretreatment and one, 3, and 6 months after RFTC treatment. We also analyzed the relationship between therapeutic outcomes and pain severity based on pre-treatment and knee MRI findings. RESULTS: No dropouts were observed. The most significant reduction in knee symptoms associated with knee osteoarthritis was observed after one month of treatment; however, at 3 and 6 months, there was a rebound effect, leading to a decrease in therapeutic efficacy. Nonetheless, there was still a noticeable decrease in symptoms due to knee osteoarthritis compared to those prior to RFTC treatment. The effect of RFTC treatment was better when pre-treatment pain was relatively less severe, knee effusion was not severe, there were no meniscal tears in the middle or posterior zones, no bone marrow edema in the middle and posterior zones of the femur and tibia, and no severe cartilage defects in the posterior femur and middle and posterior tibia. LIMITATIONS: We conducted our study without a control or a placebo group. CONCLUSION: RFTC of the genicular nerve is a good therapeutic option for controlling intractable pain following knee osteoarthritis. In addition, we found that a lower level of pain prior to treatment, along with the absence or lesser degree of knee joint effusion, as well as an absence or less severe middle or posterior knee pathologies associated with knee osteoarthritis, can predict a more favorable therapeutic outcome.

Low-frequency fatigue at maximal and submaximal muscle contractions

Skeletal muscle force production following repetitive contractions is preferentially reduced when muscle is evaluated with low-frequency stimulation. This selective impairment in force generation is called low-frequency fatigue (LFF) and could be dependent on the contraction type. The purpose of this study was to compare LFF after concentric and eccentric maximal and submaximal contractions of knee extensor muscles. Ten healthy male subjects (age: 23.6 ± 4.2 years; weight: 73.8 ± 7.7 kg; height: 1.79 ± 0.05 m) executed maximal voluntary contractions that were measured before a fatigue test (pre-exercise), immediately after (after-exercise) and after 1 h of recovery (after-recovery). The fatigue test consisted of 60 maximal (100 percent) or submaximal (40 percent) dynamic concentric or eccentric knee extensions at an angular velocity of 60°/s. The isometric torque produced by low- (20 Hz) and high- (100 Hz) frequency stimulation was also measured at these times and the 20:100 Hz ratio was calculated to assess LFF. One-way ANOVA for repeated measures followed by the Newman-Keuls post hoc test was used to determine significant (P < 0.05) differences. LFF was evident after-recovery in all trials except following submaximal eccentric contractions. LFF was not evident after-exercise, regardless of exercise intensity or contraction type. Our results suggest that low-frequency fatigue was evident after submaximal concentric but not submaximal eccentric contractions and was more pronounced after 1-h of recovery.

Importância da inervaçåo macro e microscópia do joelho no tratamento das gonalgias pela acupuntura e sua relaçåo com a teoria dos canais de energia e pontos de acupuntura da medicina chinesa / The importance of knee inervation (macro and micro) during acupuntural treatment and it's relationship with energy channels theory and the chosen acunputural points in Chinese medicine

O conhecimento da inervaçåo macro e micróscopia do joelhoé importante para compreender-se a origem e o mecanismo das gonalgias. Såo descritos os principais ramos dos nervos articulares e os nociceptores, que eståo presentes nas diferentes estruturas anatomicas que compöem o joelho. Ambos såo importantes na gênese dos arcos reflexos sômato-somático e sômato-viscerais, estes reflexos explicam as gonalgias bcom alteraçöes estruturais do membro inferior e com as manifestaçöes viscerais e psíquicas. Os autores relacionam estes conhecimentos neurofisiológicos com a teoria dos canais de energia e dos pontos de acupuntura da medicina tradicional chinesa, evidenciando-se a importância da inervaçåo e dos nociceptores no mecanismo de açåo das agulhas de acupuntura

Relación entre la cirugíaartroscópica de rodillay la activación de puntosgatillo miofasciales:presentaciónde una hipótesis / Relationship between arthroscopic surgery of the knee and activation of myofascial trigger points: presentation of a hypothesis

Desde que el Dr. Severin Nordentoft realizara la primera exploración del interior de una rodilla utilizando la artroscopia, este procedimiento ha evolucionado muchísimo a lo largo de todo el siglo XX siendo indicación absoluta en gran cantidad de procesos patológicos. Si bien la técnica a disminuido mucho las complicaciones postoperatorias, los fisioterapeutas encontramos en el tratamiento de los pacientes sometidos a artroscopia de rodilla, la activación de diferentes Puntos Gatillo Miofasciales (PGM) que explican diversos cuadros dolorosos presentados. Las posibles causas de aparición de estos PGM son: - Las adherencias y el dolor de los portales de entrada.- La isquemia quirúrgica.- El flexo de rodilla causado por el hidrartros secundario a la cirugía. Parece ser que cada causa podría activar de manera específica un grupo de PGM en los músculos flexores o extensores de rodilla. Este trabajo sugiere una hipótesis que pretende explicar esta relación de especificidad entre origen de la activación y PGM activados y pretende comprobarla en el seno de una investigación clínica (AU)

Los fibrocartílagos de la articulación femoro-tibial. Morfología y función / The knee joint menisci: morphology and function

Los meniscos de la articulación de la rodilla son estructuras fundamentales en la mecánica articular pues actúan en la distribución de las solicitaciones; la absorción de cargas; la regulación de la lubricación y en la propiocepción y estabilidad articular. Los meniscos son estructuras intermedias entre el tejido fibroso y el cartílago con fibras de colágeno dispuestas con distintas orientaciones para permitir un comportamiento mecánico adecuado. Tienen una pobre vascularización e inervación limitada al tercio externo y a los cuernos anterior y posterior aunque la superficie de la zona avascular presenta unos poros que sirven de entrada a los nutrientes del líquido synovial (AU)

The meniscus of the knee joint are fundamental structures in the articular mechanic because they act in the distribution of stresses; the absorption of loadings; the regulation of lubrication and in the proprioception and articular stability. The meniscus are intermediate structures between the fibrous tissue and the cartilage with collagen fibres disposed with different orientations to allow an appropriate mechanical behavior. They have a poor vascularization and innervation limited to the external third (vascular or red area) and the anterior and posterior horns although the avascular or white area surface presents some pores that serves as entrance to the nutriente of the synovial fluid (AU)