BACKGROUND

Knee osteoarthritis (KOA) is a prevalent degenerative joint disease. The primary pathological manifestations of KOA include articular cartilage degeneration, joint space narrowing, and osteophyte formation, leading to a spectrum of symptoms, including joint pain, stiffness, reduced mobility, diminished muscle strength, and severe disability. We aimed to utilize a meta-analysis to evaluate the efficacy of isokinetic muscle strengthening training (IMST) as a rehabilitation treatment for KOA in lowland areas.

METHODS

The study conducted a comprehensive search of the CNKI, WanFang Data, VIP Database, PubMed, Ovid MEDLINE (1946-), Cochrane Library, Embase, and CBM databases. The databases were conducted from establishing each database to September 31, 2024. The studies included were randomized controlled trials (RCTs) with participants from the plains who met the diagnostic criteria for KOA as outlined in the 2019 edition, with no restrictions on gender, age, or disease course, and no patients with advanced disease; studies where in the control group was either a non-intervention group or a group receiving treatment, other than IMST, and the experimental group received IMST alone or in addition to the treatment administered to the control group; and studies with at least two of the following outcome indicators: (i) knee flexors (Flex)/extensors (Ext) peak torque (PT), (ii) knee Flex/Ext total work (TW), (iii) knee Flex/Ext max rep total work (MRTW), (iv) knee Flex/Ext average power (AP), (v) visual analogue scale (VAS) for pain, (vi) Lequesne index (LI), (vii) Western Ontario and McMaster University Osteoarthritis Index (WOMAC), (viii) Lysholm Knee Scoring Scale (LKSS), (ix) range of motion (ROM) of the knee joint, and (x) 6-min walk test. We systematically reviewed the RCTs in both Chinese and English and evaluated the quality of the included literature. Data were processed and analyzed using ROB 2, RevMan 5.4, Stata17, and GRADEpro. The study protocol was registered on PROSPERO (CRD42024607528).

RESULTS

Thirty-three (46 studies, 2,860 patients) had low-to-some concerns risk. IMST significantly improved physical therapy outcomes, including knee Flex PT and knee Ext PT at an angular velocity of 60°/second (standardized mean difference 13.19 [95% confidence interval 6.44, 19.94], P = 0.0001 and 16.34 [11.47, 21.22], P < 0.00001, respectively), and 180°/second (11.17 [2.86, 19.48], P = 0.008 and 12.62 [3.49, 21.75], P = 0.0077, respectively); knee Flex TW (79.77 [49.43, 110.10], P < 0.0001), Ext TW (86.27 [58.40, 114.15], P < 0.00001), knee Flex MRTW (9.38 [3.20, 15.56], P = 0.003), knee Ext MRTW (15.52 [8.96, 22.08], P < 0.0001), knee Flex AP (8.66 [0.70, 16.61], P = 0.03), knee Ext AP (7.27 [3.30, 11.23], P = 0.0003), knee Flex ROM (10.62 [7.94, 13.30], P < 0.00001), and LKSS scores (7.90 [5.91, 9.89], P < 0.00001). Additionally, it reduced VAS scores (- 0.70 [- 0.92, - 0.49], P < 0.00001), LI scores (- 1.24 [- 1.65, - 0.83], P < 0.00001), and WOMAC scores (- 6.05 [- 10.37, - 1.73], P = 0.006). Compared to the control group, superior clinical efficacy was noted in the experimental group. The quality of evidence the studies reported was poor, mainly due to original trials with high inter-study heterogeneity and imprecise results. The therapeutic effect of IMST on KOA remained significant after rigorous testing of subgroup and sensitivity analyses.

CONCLUSIONS

In patients with KOA, IMST improves muscle strength and relieves joint pain and stiffness. However, large-scale, high-quality, randomized controlled trials with extended observation periods are urgently needed to popularize the use of IMST in KOA patients.