Personalized Weight-Bearing With Smart Crutch Tips After Surgery for Tibial Plateau Fractures

Time in days from plate fixation to the first radiographic examination confirming complete fracture union. Complete union is defined as disappearance of the fracture line due to filling with bone tissue and complete bone remodeling at the fracture site. Anteroposterior, lateral, and oblique radiographs are compared with previous images and assessed by two independent radiologists blinded to treatment group allocation. Disagreements are resolved by a third blinded radiologist. Partial union does not meet the endpoint. The event date is the date of the first examination confirming complete union.

Proportion of participants with secondary loss of reduction on radiographs compared with the first postoperative radiographic examination. Loss of reduction is defined as at least one of the following changes: an increase in articular surface depression of at least 2 mm; an increase in interfragmentary gap of at least 2 mm; an increase in tibial plateau width of at least 5 mm; or worsening of varus/valgus alignment or posterior tibial slope by at least 5 degrees. These thresholds refer to changes from the postoperative baseline, not absolute residual displacement. Radiographs are assessed independently by radiologists blinded to treatment group allocation. Each participant is counted once, regardless of the number of criteria met. Insufficient imaging without a confirmed positive finding is classified as indeterminate, not as absence of loss of reduction

Patient-reported knee outcomes assessed using the five KOOS subscales: Pain, Other Symptoms, Activities of Daily Living, Sport and Recreation Function, and Knee-Related Quality of Life. Each subscale is scored separately from 0 to 100, with higher scores indicating fewer knee problems. No overall total score is calculated. Assessments are performed at all attended in-person follow-up visits. Weeks 8, 16, and 52 are the mandatory time points for comparison between groups. Assessments at conditional visits are analyzed accounting for cancellation of these visits after confirmed fracture union.

Knee function assessed using the Rasmussen Clinical Score, covering pain, walking capacity, knee extension, range of motion, and knee stability. Higher scores indicate better knee function. Range of motion is measured with a goniometer. Weight-bearing tests are performed only when clinically safe. Assessments are conducted at all attended in-person follow-up visits, with weeks 8, 16, and 52 serving as the mandatory time points for comparison between groups.

Fear of movement assessed using the 17-item Tampa Scale of Kinesiophobia (TSK-17). Total scores range from 17 to 68, with higher scores indicating greater fear of movement or reinjury. The first assessment is conducted remotely immediately after participant training at the week 3 visit, and the assessment is repeated at week 8. The first assessment is a post-training measurement and is not considered a pre-intervention baseline.

Percentage of technically valid recorded steps within the prescribed loading range in the individualized rehabilitation group. The analytical range is the prescribed target ±10 percentage points of body weight, with a lower limit of zero. Each step is compared with the prescription active at the time of recording. Only days with at least 20 technically valid steps and a known prescription are included. Adherence is calculated as 100 × valid steps within range / all valid steps on eligible days. It is summarized over the entire restriction period and separately by postoperative week. Higher percentages indicate greater adherence. Days with insufficient data are excluded, not assigned 0% or 100%. Participants without eligible data are classified as not evaluable. This outcome is not calculated in the usual-care group.

Proportion of participants with implant breakage or deformation, or implant migration or loosening associated with loss of stability. Events are documented using available imaging and clinical assessments. The date, type of failure, diagnostic findings, and treatment are recorded. Fixation failure is assessed separately from secondary loss of fracture reduction. Each participant with at least one qualifying event is counted once, regardless of the number of fixation failure events.

Proportion of participants with symptomatic deep vein thrombosis confirmed by diagnostic imaging or another appropriate instrumental examination. Routine ultrasound screening for asymptomatic thrombosis is not performed. The date, diagnostic findings, and treatment of each confirmed event are recorded. Each participant with at least one confirmed symptomatic event is counted once, regardless of the number of events.

Proportion of participants with at least one infectious complication related to the study fracture or its treatment, including deep infection. The date, infection site, diagnostic findings, and treatment are recorded. Each participant with at least one qualifying infection is counted once, regardless of the number of infectious events.

Proportion of participants undergoing at least one additional operation because of a complication of the study fracture or its treatment. Implant removal or replacement due to a complication is included, even if the procedure was scheduled in advance. Routine implant removal without complications and operations for unrelated diseases or injuries are excluded. The date and indication for each qualifying operation are recorded. Each participant is counted once, regardless of the number of qualifying reoperations.