Operative Indications for Lateral Compression Type 1 Pelvic Ring Injuries: A Systematic Review of Reported Selection Criteria

Background/Objectives: Lateral compression type 1 (LC-1) injuries range from stable patterns to injuries whose instability is not evident on initial imaging. How published studies define the criteria for operative fixation has not been characterized. Methods: We systematically reviewed studies reporting operative-selection criteria for LC-1 injuries. MEDLINE and Embase were searched (last update 14 August 2026) without date or language filters; English-language full text was required for eligibility, and dedicated fragility-fracture cohorts were excluded. Reports of the same or nested cohorts were linked into study-level units. Each unit was coded for indication category, assessment method, quantitative threshold, and selection-rule reconstructibility (whether the assessment, positive rule, and link to the operation could be reconstructed). A second clinician independently recoded three of these fields for all units. Registration (retrospective): OSF, 10.17605/OSF.IO/WSDGX. Results: Thirty-seven eligible reports contributed 29 study-level units. Selection was multifactorial in 15 units (51.7%), 16 (55.2%) used dynamic or stress assessment, and 18 (62.1%) reported a quantitative threshold, most often approximately 1 cm (10 units; 7 after collapsing four units from one institutional registry). Only 6 units (20.7%) met the prespecified definition of a fully reconstructible operative-selection rule. Of the remaining 23, two, by design, had no ascertainable clinical selection pathway; the other 21 all lacked a reconstructible positive rule (14 units), a clear criterion-to-treatment linkage (16), or both, whereas the assessment itself was non-reconstructible in only two. Inter-coder agreement for selection-rule reconstructibility was 89.7% (26/29). Conclusions: Operative indications for LC-1 injuries remain heterogeneous and incompletely operationalized. What to assess was almost always identifiable; reconstruction failed after it. Studies should report how instability is elicited, how a positive test is defined, and what that result caused.