Patients
This randomized prospective blinded study was carried out on all consecutive patients with radiologically proven symptomatic knee joint osteoarthritis not responding to medical treatment, referred to the university hospital for pain management from January 2019 to November 2020. The study protocol was approved by the local ethics committee before the start of the study. Radiological severity was assessed using the Kellgren and Lawrence global scale [15] as follow: Grade 0; means absence of radiological finding; grade 1: suspected narrowing of joint space; grade 2 refers to osteophytes and possible narrowing; grade 3 is defined as multiple osteophytes, definite narrowing of joint space and grade 4 comprises large osteophytes, marked narrowing of joint space.
All patients were evaluated by a consultant of physical medicine, rheumatology and rehabilitation. Patients with knee pain of moderate or greater intensity on most or all days for ≥ 3 months, showing significant radiological OA (Kellgren-Lawrence grade 2 to 4) were initially included in the study. Patients with previous knee surgery, acute knee pain, connective tissue diseases affecting the knee joint, sciatic pain, previous intra-articular or peri-articular interventions and those who were lost to follow up to 8 weeks after knee joint injection were excluded. The study included 40 patients and were randomly distributed to two equal groups. Groups 1 was managed with ultrasound-guided IACSI and group 2 with ultrasound-guided GNB. All patients were blinded to the management procedure. Informed written consent to participate in the study was obtained from all participants.
Interventional procedures
All procedures were performed with patients placed in supine position, under complete aseptic conditions and were guided with ultrasound (ACUSON X 300, Siemens Healthineers AG, Erlangen, Germany) using a 10 MHz linear transducer. Single operator with four years’ experience in ultrasound guided interventions performed all the injections. Evaluation of the management response at all follow up periods were assessed by another physician who was blind to the management procedure.
For the GNB group, GNB was carried out using the same technique previously described by Kim et al. [1]. GNB target points for injection were close to the superior lateral, superior medial, and inferior medial genicular arteries that were identified near the periosteal areas at the junctions of the epicondyle and the shafts of the femur and tibia and this was confirmed with Doppler ultrasound [1] (Fig. 1).
Target point for the IACSI group was the suprapatellar bursa, determined as a thin anechoic space in the mid-longitudinal ultrasound view, deep to the quadriceps tendon, and superficial to the metaphysis of the femur, referring the superior margin of patella as a landmark to identify its inferior aspect [8] (Fig. 2).
All procedures were performed with a spinal needle (22 G) introduced with ultrasound guidance till reaching the designated target points at both groups. For the GNB group, a mixture of 20 mg of Triamcinolone Acetonide (TA) and 6 mL of lidocaine was equally divided and injected near each of three genicular arteries [1]. While for the IACSI group, a total mixture of 6 cc consisting of 1 mL TA (40 mg) and 5 mL lidocaine inside the suprapatellar bursa [16, 17].
Outcome measurements and follow-up
The severity of pain and the functional capacity of the managed knee joint were evaluated before procedures (as a baseline) and at 2, 4 and 8 weeks after injection at both groups using the visual analog score (VAS) and Oxford knee score (OKS) respectively.
VAS consisted of a graded scale from 0 to 100 (point zero: no pain and point 100 is unbearable pain) and patients were asked to plot a point that corresponds to their pain severity. OKS consist of 12-item questionnaires. Each question was scored from 1 to 5 (one is the least symptoms). Scores from the 12 questions were added to end with a total score between 12 and 60 (12 presents the most favorable outcome) [18]. The absolute values of these scores were collected and compared. The overall benefit from either techniques was evaluated and the differences between the mean values of VAS and OKS obtained at initial pre-procedural baseline and those obtained at 2, 4 and 8 weeks were recorded separately.
Clinical success was defined as decrease of VAS score by at least 5 points [19].
After the injection and during the whole period of follow up, patients were not instructed to adopt any particular recommendations or precautions, didn't receive any oral analgesics, and were not assigned to any rehabilitation program.
Statistical analysis
Data were fed to the computer and analyzed using IBM SPSS software package version 20.0. (Armonk, NY: IBM Corp). Qualitative data were described using number and percent. The Kolmogorov–Smirnov test was used to verify the normality of distribution. Quantitative data were described using range (minimum and maximum), mean, standard deviation, median, and interquartile range (IQR). Significance of the obtained results was judged at the 5% level.
Chi-square test was used for categorical variables to compare between different groups, Fisher’s Exact Correction for chi-square when more than 20% of the cells have expected count less than 5, Student t-test For normally distributed quantitative variables, to compare between two studied groups, ANOVA with repeated measures for normally distributed quantitative variables, to compare between more than two periods or stages, Post Hoc test (Bonferroni adjusted) for pairwise comparisons, and Mann Whitney test For abnormally distributed quantitative variables, to compare between two studied groups.