Objective To explore the value of acupuncture at “relative point” combined with isometric contraction training of quadriceps femoris (QF) for knee osteoarthritis (KOA) in the elderly patients. Methods Clinical data of 106 elderly KOA patients admitted to our hospital from May 2021 to May 2023 were collected and retrospectively analyzed. According to their rehabilitation treatment regimens, they were divided into observation group (n=51, acupuncture at “relative point” combined with QF isokinetic contraction training) and control group (n=55, QF isokinetic contraction training). The rehabilitation efficacy, visual analogue scale (VAS) score, score of ability of daily living (ADL) scale, Lysholm score, serum levels of interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α) and vascular endothelial growth factor (VEGF), and peak torque value, total muscular work and average muscular power of QF were compared between the two groups. SPSS statistics 22.0 was used for data analysis. Based on data type, student′s t test orχ² test was employed for intergroup comparison. Results The total effective rate of rehabilitation efficacy was significantly higher in the observation group than the control group (90.20% vs 70.91%, P<0.05). The observation group had obviously lower VAS and ADL scores after intervention [(2.04±0.67) and(2.08±0.80)points] when compared with the scores before intervention [(6.18±1.51) and (7.56±1.49)points], and with those in the control group after intervention [(3.88±1.05) and (3.97±1.22)points], and notably higher Lysholm score (75.19±10.15) after intervention than that before intervention (55.95±6.53) and that of the control group (69.44±8.36) after intervention (all P<0.05). The levels of IL-1β, TNF-α and VEGF in synovial fluid of the observation group after intervention [(6.19±1.00) pg/ml, (1.14±0.46) pg/ml, (320.36±37.12) ng/ml] were significantly lower than those before intervention [(15.81±3.19) pg/ml, (5.50±1.03) pg/ml, (557.15±84.06) ng/ml] and control group after intervention [(9.16±2.12) pg/ml, (2.88±0.73) pg/ml, (411.50±50.27) ng/ml, all P<0.05]. Statistical increments were observed in the observation group after intervention in terms of QF peak torque value, total muscular work and average muscular power than before intervention and in the control group after intervention [(70.22±14.11) vs (52.14±10.36) and (63.28±13.06) N.m; (418.94±73.15) vs (249.28±67.30) and (355.24±70.27) J; (42.57±11.19) vs (30.69±8.25) and (38.14±10.26) W; P<0.05]. During rehabilitation treatment, adverse reactions occurred only in the observation group, including subcutaneous hematoma in one case and needle stagnation in two cases. All these symptoms disappeared after symptomatic treatment, and no pain or swelling of knee joint was observed. Conclusion Acupuncture to “relative point” combined with QF isometric contraction training can alleviate pain and improve joint function in elderly KOA patients.