Proximal humerus fractures (PHFs) are the third most common non-vertebral fractures in the elderly. Most elderly experience loss of function following a PHF regardless of treatment. A Cochrane review from 2015 concluded that surgical management is not superior to non-surgical management, and that the optimal non-surgical management after PHF is not known. Therefore, the aim of this study is to evaluate the effectiveness of usual rehabilitation care after displaced PHF compared with one-time physiotherapy instruction.

Proximal humerus fractures (PHFs) are the closely related to osteoporosis. The lifetime risk of suffering a PHF in females aged 50 or above is 13%. About half of the fractures are minimally displaced and usually managed by short immobilization, analgetics, and early mobilization. The remaining half of the patients suffer from displaced fractures, traditionally managed surgically by open reduction and internal fixation or shoulder replacement. Within the last decades, an increasing number of high-quality randomized controlled trials (RCTs) and meta-analyses have failed to document the superiority of surgical management in displaced PHFs. Therefore, an increasing number of patients are being offered nonsurgical treatment consisting of immobilization followed by rehabilitation that may vary across countries and regions. Most elderly experience loss of function following a PHF regardless of treatment. However, optimal management and recovery of function are paramount to prevent a substantial impact on the patient's independent living and morbidity. A systematic review and metaanalysis from 2021 concluded a need for high-quality RCTs to substantiate the current evidence regarding the need for supervision after a PHF.

It is assumed that rehabilitation delivered as structured training benefits patients with PHFs, but this is not known from current evidence. It is possible that patients are even harmed with intensive training programmes. Most RCTs with a non-surgically treated group use the same exercise intervention in the two groups to best identify the difference between surgery and non-surgical treatment. Therefore, the effect of training cannot be concluded from these studies. This is supported by an expectation of more nonsurgically treated displaced PHFs due to the growing evidence of no benefit from surgery. The current study is a prerequisite for future rehabilitation studies comparing different training modalities. Therefore, this study aims is to evaluate the effectiveness of usual rehabilitation care after displaced PHF compared with one-time physiotherapy instruction.

Inclusion Criteria:

• Patients aged 60 years or above with displaced PHFs (Neer's definition) including 2-, 3-, or 4-part fractures after a low energy trauma will be recruited.

Prior to first visit in the outpatient clinic all patients with PHFs will be screened for eligibility based on initial radiographs and medical records by an experienced orthopaedic consultant (senior author SB) at Zealand University Hospital, Køge, Denmark. The senior author classifies fracture categories.

• Patients should be cognitively capable of answering patient-reported outcome measures.

Exclusion Criteria:

• Dependent on daily personal care for basic activities of daily living
• Diagnosed with dementia or institutionalized
• Does not understand written and spoken guidance in Danish
• Pathological fracture or previous fracture in the same proximal humerus
• Concomitant injury or fracture.
• Polytrauma, high-energy trauma, or multiple fractures
• Fracture dislocation or articular surface fracture
• Isolated tuberosity fracture
• Fractures not expected to heal by non-surgical treatment (no bony contact between head and shaft in both views)
• The senior author considers the patient unsuitable to attend the study for medical reasons (substance abuse, affective or psychotic disorders, apoplexy, chronic pain, malignant disease)
• Symptomatic glenohumeral osteoarthritis, rheumatoid arthritis, or rotator cuff-arthropathy

Anonymised data on group level will be made available upon reasonable request after the primary publications have been published.

Patients will not know the direction of our hypothesis. A blinded statistician will perform the primary analysis.