Ultrasound-based evaluation revealed reliable postoperative knee stability after combined acute ACL and MCL injuries

Abstract

Purpose Anterior cruciate ligament (ACL) injuries are often combined with lesions of the medial collateral ligament (MCL). The aim of this study was to evaluate treatment outcome of combined acute ACL and MCL lesions using functional US and clinical examination. Methods Patients aged > 18 years undergoing primary ACL reconstruction with concomitant operative (group 1) or non-operative treatment of the MCL (group 2) between 2014 and 2019 were included after a minimum follow-up of 12 months. Grade II MCL injuries with dislocated tibial or femoral avulsions and grade III MCL ruptures underwent ligament repair whereas grade II injuries without dislocated avulsions were treated non-operatively. Radiological outcome was assessed with functional US examinations. Medial knee joint width was determined in a supine position at 0° and 30° of knee flexion in unloaded and standardized loaded (= 15 Dekanewton) conditions using a fixation device. Clinical examination was performed and patient-reported outcomes were assessed by the use of the subjective knee form (IKDC), Lysholm score, and the Tegner activity scale. Results A total of 40 patients (20 per group) met inclusion criteria. Mean age of group 1 was 40 ± 12 years (60% female) with a mean follow-up of 33 ± 17 months. Group 2 showed a mean age of 33 ± 8 years (20% female) with a mean follow-up of 34 ± 15 months. Side-to-side differences in US examinations were 0.4 ± 1.5 mm (mm) in 0° and 0.4 ± 1.5 mm in 30° knee flexion in group 1, and 0.9 ± 1.1 mm in 0° and 0.5 ± 1.4 mm in 30° knee flexion in group 2, with no statistically significant differences between both groups. MCL repair resulted in lower Lysholm scores (75 ± 19 versus 86 ± 15; p < 0.05). No significant differences could be found for subjective IKDC or Tegner activity scores among the two groups. Conclusion A differentiated treatment concept in combined ACL and MCL injuries based on injury patterns leads to reliable postoperative ligamentous knee stability in US-based and clinical examinations. However, grade II and III MCL lesions with subsequent operative MCL repair (group 1) result in slightly poorer subjective outcome scores. Level of evidence Retrospective cohort study; Level III

The medial knee gap measured on ultrasound images is wider during a valgus stress test compared to the anterior medial knee rotation test

“…Slane et al 29 reported a medial joint gap width of 8.7 mm in an unloaded condition and 10.7 mm with an applied 10 daN valgus force in cadaveric knees. The most recent report by Lutz et al 30 reported an unloaded medial joint gap width of 6.1 mm and with an applied 15 daN force a medial joint gap width of 7.4 mm. The investigators of the current study did not control or measure the applied valgus and knee rotational forces, but all test trials were performed by the same athletic trainer with 20 years of clinical experience.…”

Dynamic Ultrasound Can Accurately Quantify Severity of Medial Knee Injury: A Cadaveric Study

“…The assessment of MCL reconstruction and repair techniques could benefit from the measurement of medial compartment gapping, as improvements in technique have been linked to better results. 9,26-28 Lutz et al 18 recently used ultrasonography and clinical examination to evaluate treatment outcomes of combined acute ACL and MCL injuries. In this retrospective study, 40 patients with ACL and MCL injuries were equally assigned to 1 of 2 treatment groups.…”

“… 9 , 26 , 27 , 28 Lutz et al. 18 recently used ultrasonography and clinical examination to evaluate treatment outcomes of combined acute ACL and MCL injuries. In this retrospective study, 40 patients with ACL and MCL injuries were equally assigned to 1 of 2 treatment groups.…”

“…In recent years, dynamic portable ultrasonography is increasingly being applied to musculoskeletal conditions. 17 , 18 , 19 Apart from almost universal portability, other benefits of this modality include its low cost, lack of radiation, ready availability at the point of care, and ability to easily visualize and compare contralateral healthy anatomic structures under applied stress. Previous studies have demonstrated that ultrasonography is a reliable and accurate tool for qualitatively assessing medial knee injuries and that it is comparable with MRI in assessing medial knee ligaments.…”