Atypical Multi-ligamentous Knee Injury (MLKI): Binary Injury with Avulsion of One Cruciate and Tear of the Other, or Bi-cruciates Avulsion with or Without Collateral Ligament Injury Following Road Traffic Accidents (RTA).

Background: Multi-ligamentous knee injuries (MLKI) fall within a narrow spectrum, accounting for around 11% of all knee injuries. Atypical MLKI involve binary injury: avulsion of one cruciate and tear of the other, or both cruciates avulsion with or without collateral ligament injury.

Purpose: The purpose of this study is to analyse the clinical and radiological outcomes of patients diagnosed with atypical MLKI, and to assess the differences in outcomes between patients with collateral injury and those without.

Methods: 66 patients with atypical MLKI were studied and compared in this retrospective cohort. 32 of these patients did not have collateral injuries, while the remaining 34 patients did have collateral injuries. The duration of the study was from 2010 to 2022. Reconstruction for the cruciate tears and open or arthroscopic reduction and fixation (ORIF/ARIF) of the cruciate avulsion were performed. In earlier years (2010-2015), posterior cruciate ligament avulsions were open reduced and fixed using the double draping approach. However, in later years (2016-2022), the double draping method was replaced by the single draping technique. Conservative or surgical management of the collateral ligaments was determined based on factors such as intraoperative laxity, tissue quality, injury site, and chronicity. Group 1 comprised of atypical MLKI patients without collateral ligament injuries, while Group 2 included atypical MLKI patients with collateral ligament injuries and subgroup was based on the various combinations of cruciate avulsions, tears and collateral injuries. A comparative statistical analysis was conducted on the International Knee Documentation Committee (IKDC) score, Lysholm score, knee flexion range of motion (ROM), and laxity on stress radiographs.

Results: The male:female ratio were 54:12 patients. The average follow-up was 26.48 months (range 23-30 months). The average age of the patients is 37.66 (range 20-50 years). All patients had significant improvement from pre-operative scores to final follow-up scores (P < 0.001). There was no significant difference between the atypical MLKI with collateral and atypical MLKI without collateral injury in terms of the postoperative IKDC score (P = 0.154), Lysholm score (P = 0.387), knee flexion ROM (P = 0.314), and laxity on radiographs with anterior stress (P = 0.108) and posterior stress (P = 0.272). The intergroup analysis was not statistically significant. There was no significant difference in patients' functional outcomes at final follow-up based on fixation modality. Patients recovered to their pre-injury activity levels without knee joint giving way on daily activities. None of the patients in our series had infections.

Conclusion: The incidence of atypical MLKI in multi-ligamentous injury was 9.53% (66/692). Atypical MLKI with cruciate avulsion can be treated with ARIF and cruciate tears with reconstruction in single-stage single draping method with good clinical and radiographic results. Atypical MLKI with or without collateral ligament injury had similar outcomes when appropriate techniques are instituted to address collateral ligaments.