BackgroundOsteoarthritis (OA) of the hip and the knee is common and leads to pain, stiffness and disability. Clinical practice guidelines (CPG) provide recommendations to assist healthcare professionals in clinical decision-making. Although evidence-based physiotherapy has been shown to be effective in the management OA, a gap between clinical practice and guideline recommendations exists. Little is known about OA management provided by physiotherapists in Germany and whether treatment aligns with CPGs. The objectives of this study were (1) to investigate the current physiotherapy practice in patients with hip and/or knee OA in Germany, (2) to evaluate physiotherapists’ adherence to guideline recommendations and (3) to explore barriers and facilitators to guideline use.MethodsA cross-sectional online survey was conducted among physiotherapists. The questionnaire collected information on demographic characteristics, physiotherapists’ management of hip and knee OA and the use of CPGs in clinical practice. Guideline adherence was evaluated by comparing the survey findings with guideline recommendations. Full adherence was assumed if all recommended treatment options were chosen.ResultsIn total, 447 (74.9%) of 597 eligible physiotherapists completed the survey. Data from 442 participants (mean age 41.2 ± 12.8 years; 288 female (65.1%)) were included in the analysis. The most common treatment choices for both hip and knee OA were exercise therapy (hip OA: 424/442, 95.9%; knee OA: 426/442, 96.4%), self-management advice (hip OA: 413/442, 93.2%; knee OA: 395/442, 89.4%) and education (hip OA: 325/442, 73.5%; knee OA: 331/442, 74.9%), followed by manual therapy (hip OA: 311/442, 70.4%; knee OA: 311/442, 70.4%) and joint traction (hip OA: 208/442, 47.1%; knee OA: 199/442, 45.0%). Full guideline adherence was found in 17.2% (76/442) of physiotherapists for hip OA management and in 8.6% (38/442) for knee OA. Less than half of the respondents (212/430, 49.3%) were aware of an OA guideline.ConclusionsIn accordance with current guideline recommendations, most physiotherapists provide exercise therapy and education for patients with hip and/or knee OA. Interventions with low or conflicting evidence were also frequently provided. The limited awareness of existing OA guidelines and the low guideline adherence indicate an insufficient implementation of CPGs in German physiotherapy practice.Trial registrationGerman Clinical Trials Register (DRKS00026702). Registered 14 October 2021.Supplementary InformationThe online version contains supplementary material available at 10.1186/s12891-023-06464-0.