Individual and Combined Anatomic Risk Factors for the Development of an Anterior Cruciate Ligament Rupture in Men: A Multiple Factor Analysis Case-Control Study

Background: No comparative studies have evaluated anatomic risk factors in a large cohort including both patients with anterior cruciate ligament (ACL) ruptures and healthy participants. Purpose: To determine which anatomic parameters are independently associated with an ACL rupture and the diagnostic values of the individual and combined anatomic parameters. Study Design: Case-control study; Level of evidence, 3. Methods: A total of 352 male patients who underwent arthroscopic ACL reconstruction because of a primary ACL rupture and 350 age-, sex-, body mass index–, and side dominance–matched healthy participants were included. Measurements of 32 previously determined parameters and 7 calculations were performed. Between-group differences were calculated. Univariate and multivariate logistic regression models and receiver operating characteristic curve analysis were conducted for the individual and combined independently associated factors. Results: The mean age and body mass index of all participants were 29.9 ± 7.7 years and 27.2 ± 3.1, respectively. There were significant differences between the groups regarding the notch width (NW), notch shape index, anterior tibial slope, notch width index, NW–eminence width (NW:EW) ratio, notch height, axial lateral wall angle, medial intercondylar ridge thickness, alpha angle, medial tibial depth (MTD), lateral tibial slope (LTS), coronal tibial plateau width, eminence width index, tibial proximal anteroposterior distance (TPAP), lateral condylar anteroposterior distance (LCAP)/TPAP, ACL cross-sectional area, ACL volume, medial and lateral meniscal cartilage height, medial and lateral meniscal cartilage angle (MCA), and medial and lateral meniscal cartilage bone height. The NW:EW ratio (odds ratio [OR], 4.419; P = .017), MTD (OR, 8.617; P = .001), LTS (OR, 2.254; P = .011), LCAP/TPAP (OR, 2.782; P = .037), and medial MCA (OR, 1.318; P = .010) were independently associated with the development of an ACL rupture. Combining the independently associated factors revealed a sensitivity of 93% and a specificity of 94% (area under the curve, 0.968). Conclusion: Patients with ACL ruptures could be distinguished from uninjured controls with high sensitivity and specificity via the combined use of the NW:EW ratio, MTD, LTS, LCAP/TPAP, and medial MCA. In clinical practice, these findings may contribute to the development of preventive strategies for ACL ruptures.

The influence of anesthesia- body mass index and chronicity of the injury on the reliability of diagnostic tests for anterior cruciate ligament rupture

This study aimed to analyze the accuracy and interobserver reliability of the four common diagnostic tests for anterior cruciate ligament (ACL) rupture. The effect of anesthesia, chronicity of the injury and patient’s body mass index (BMI) on the reliabilities was also assessed. Patients who underwent arthroscopic knee surgery were examined before the surgery and under anesthesia by three observers categorized based on their experience levels. One hundred two patients were evaluated to determine the accuracy of these tests. Sixty-two patients with ACL rupture were further examined to assess the effect of BMI (≤ 25 kg/m2, or > 25 kg/m2) and chronicity (≤ 4 or > 4 weeks) of the injury on reliabilities with using the Fleiss kappa method. The Lachman test performed under anesthesia had the highest sensitivity (100%, 100%, and 96.7%). In contrast, pivot shift and lever sign tests had the lowest sensitivity both in awake (24.2%, 17.7%, 8.1% and 37.1%, 33.8%, 29%) and anesthetized condition (75.8%, 75.8%, 67.7% and 41.9%, 43.5%, 40.3%). Specificities of the tests except pivot shift were negatively affected when performed under anesthesia. The reliability of the anterior drawer test was perfect under anesthesia. The lever sign test had the highest reliability in the awake condition in patients with a BMI of > 25 kg/m2. Furthermore, the reliabilities of the anterior drawer, Lachman, and pivot-shift tests in awake condition were found to be increased in patients with a chronic injury. Finally, the examiner’s experience is not important for the physical diagnosis of ACL rupture.

Reconstruction of Anterior Cruciate Ligament Over 50 Years Old? Yes, or No

Background: The aim of the study is to compare the results of anterior cruciate ligament reconstruction (ACL-R) in people aged more than 50 and under 30 years of age. Methods: A total of 64 patients with ACL rupture were evaluated for eligibility. Thirty-two patients with ACL rupture, aged more than 50 years (54.38 ± 1.26) were matched in all of the background factors, with 32 patients suffering from ACL rupture under 30 years old. They were followed for clinical and functional results at six and on average 45.58 months after surgery. These evaluations included the Lachman test, KT-1000, International Knee Documentation Committee (IKDC) score, Lysholm knee score (LKS), return to exercise activity, post-operative satisfaction rate, and pain intensity based on Visual Analogue Scale (VAS) and rates of extension and flexion loss. Results: Our findings indicated that knee stability, return to exercise activity, LKS and IKDC scores, as well as pain intensity and satisfaction were significantly improved in both groups. Indeed, the satisfaction rate of patients over 50 years at six months after surgery was less than those under 30 years (P < 0.001); however, it was approximately similar to the group under 30 years of age in the final follow-up (P > 0.05). The rate of return to sports activity was also lower in patients over 50 years. Conclusions: The comparable results at the patients with < 30 years demonstrated that arthroscopic ACL-R in patients over 50 years of age with no or mild DJD has good results.

Laxity measurement of internal knee rotation after primary anterior cruciate ligament rupture versus rerupture

Purpose The aim of the current study was to objectify the rotational laxity after primary anterior cruciate ligament (ACL) rupture and rerupture after ACL reconstruction by instrumented measurement. It was hypothesized that knees with recurrent instability feature a higher internal rotation laxity as compared to knees with a primary rupture of the native ACL. Study design Cross-sectional study, Level of evidence III. Methods In a clinical cross-sectional study successive patients with primary ACL rupture and rerupture after ACL reconstruction were evaluated clinically and by instrumented measurement of the rotational and antero-posterior laxity with a validated instrument and the KT1000®, respectively. Clinical examination comprised IKDC 2000 forms, Lysholm Score, and Tegner Activity Scale. Power calculation and statistical analysis were performed (p value < 0.05). Results 24 patients with primary ACL rupture and 23 patients with ACL rerupture were included. There was no significant side-to-side difference in anterior translation. A side-to side difference of internal rotational laxity ≥ 10° was found significantly more frequent in reruptures (53.6%) compared to primary ruptures (19.4%; p < 0.001). A highly significant relationship between the extent of the pivot-shift phenomenon and side-to-side difference of internal rotation laxity could be demonstrated (p < 0.001). IKDC 2000 subjective revealed significantly better scores in patients with primary ACL tear compared to patients with ACL rerupture (56.4 ± 7.8 vs. 50.8 ± 6.2; p = 0.01). Patients with primary ACL tears scored significantly better on the Tegner Activity Scale (p = 0.02). No significant differences were seen in the Lysholm Score (p = 0.78). Conclusion Patients with ACL rerupture feature significantly higher internal rotation laxity of the knee compared to primary ACL rupture. The extend of rotational laxity can be quantified by instrumented measurements. This can be valuable data for the indication of an anterolateral ligament reconstruction in ACL revision surgery.

Coronal subluxation of the tibiofemoral joint before and after anterior cruciate ligament reconstruction

Background Studies have shown that medial subluxation of the tibia occurs after anterior cruciate ligament (ACL) rupture. However, it is unclear whether anterior cruciate ligament reconstruction (ACLR) can correct tibial coronal subluxation. Purpose To determine whether the tibia is medially subluxated after ACL rupture, and whether ACLR can correct medial subluxation of the tibia. Study design Case series; Level of evidence, 4, Retrospective clinical study. Methods The distance of tibial coronal subluxation before and after ACLR surgery was measured in 48 patients with ACL rupture and meniscus injury. Tibiofemoral subluxation was defined as the perpendicular distance between the long axis of the tibia and a second parallel line originating at the most proximal aspect of the femoral intercondylar notch. To determine the long axis of the tibia, two circles separated by 5 cm were centered on the proximal tibia. The proximal circle is 5 cm from the tibial plateau, and the distal circle is 5 cm from the proximal circle. The line passing through the center of the two circles was considered the long axis of the proximal tibia. Care was taken to ensure that each patient lied on the back with their patellae facing upward, to minimize rotational variation among the radiographs. At the same time, 30 patients with simple meniscus injury who underwent arthroscopy during the same period were selected to determine the degree of tibiofemoral coronal subluxation as the baseline value. The changes before and after operation were compared, as well as the differences with the baseline data. Result The average follow-up period was 21.2 ± 5.8 months. The average distance of tibial coronal subluxation before ACLR was 5.5 ± 2.1 mm, which was significantly different from that of baseline group (7.3 ± 2.1 mm) (P < 0.001). The tibial subluxation after ACLR was 7.7 ± 2.6 mm, which was significantly different from that before operation (P < 0.001). There was no significant difference in the distance between postoperative tibial subluxation and baseline group (P = 0.472). Conclusion The tibia was coronally medially subluxated after ACL rupture. ACLR can correct the medial subluxation of tibia. This finding is helpful in the diagnosis of ACL rupture, and can be used to assess the imaging status of the tibiofemoral joint on the coronal plane during or after ACLR.

“I don't opt out of things because I think I will get a sore knee, but I don't expose myself to stupid risks either”: patients’ experiences of a second ACL injury—an interview study

Purpose The purpose of this qualitative study was to describe women’s experiences with anterior cruciate ligament reconstruction (ACLR) and a subsequent ACL rupture, and to identify potential facilitators and barriers for coping with rehabilitation after the second injury. Methods Eight women between 17 and 36 years (mean 26, SD 6.5) who had experienced ACLR, followed by another ACL rupture, participated in the study. Semi-structured interviews were conducted, and data were analyzed using qualitative content analysis. Results One overarching theme, “Rehabilitation after a second ACL injury—A lifelong adaptive coping process”, emerged from analyses. Undergoing a second rehabilitation is described as a process of adaptation, beginning with the first injury and still ongoing, more than 5 years later. Participants applied different coping strategies to adapt to these life-altering injuries, but the common denominator was of major life adjustments with no return to previous activity levels. Initially, after the reinjury, it was about coping with the catastrophe of the dreaded second injury. Over time, they accepted their “new” life and reset their recovery/rehabilitation goal not just as “return to sport” but rather as a “personal life goal”. Conclusion Undergoing a second ACL injury is a long process that challenges the patient’s coping skills. Given these results, rehabilitation programs need to be more person centred according to the patients-adjusted life goals. Level of evidence 3.

An Anterior Cruciate Ligament Rupture Increases Levels of Urine N-terminal Cross-linked Telopeptide of Type I Collagen, Urine C-terminal Cross-linked Telopeptide of Type II Collagen, Serum Aggrecan ARGS Neoepitope, and Serum Tumor Necrosis Factor–α

Background: An anterior cruciate ligament (ACL) rupture results in an increased risk of developing knee osteoarthritis (OA) at an early age. Before clinical signs become apparent, the OA process has already been initiated. Therefore, it is important to look at the cascade of changes, such as the activity of cytokines and proteases, which might be associated with the later development of OA. Purpose: To compare biomarker levels in patients with a recent ACL rupture with those in controls with a healthy knee and to monitor biomarker levels over 2 years after an ACL rupture. Study Design: Descriptive laboratory study. Methods: Patients were enrolled after an ACL tear was identified. Serum and urine samples were collected at the time of enrollment in the study (3-25 weeks after the injury) and then at 14 and 27 months after the injury between January 2009 and November 2010. Reference samples were obtained from participants with healthy knees. The following biomarkers were measured with immunological assays: aggrecan ARGS neoepitope (ARGS-aggrecan), tumor necrosis factor–α (TNF-α), interferon-γ, interleukin (IL)–8, IL-10, IL-13, N-terminal cross-linked telopeptide of type I collagen (NTX-I), and C-terminal cross-linked telopeptide of type II collagen (CTX-II). Results: Samples were collected from 152 patients with an acute ACL rupture, who had a median age of 25 years (interquartile range [IQR], 21-32 years). There were 62 urine reference samples (median age, 25 years [IQR, 22-36 years]) and 26 serum reference samples (median age, 35 years [IQR, 24-39 years]). At a median of 11 weeks (IQR, 7-17 weeks) after trauma, serum levels of both ARGS-aggrecan and TNF-α were elevated 1.5-fold ( P < .001) compared with reference samples and showed a time-dependent decrease during follow-up. Urine NTX-I and CTX-II concentrations were elevated in an early phase after trauma (1.3-fold [ P < .001] and 3.7-fold [ P < .001], respectively) compared with reference samples, and CTX-II levels remained elevated compared with reference samples at 2-year follow-up. Strong correlations were found between serum ARGS-aggrecan, urinary NTX-I, and urinary CTX-II ( rs = 0.57-0.68). Conclusion: In the first few months after an ACL injury, there was a measurable increase in serum levels of ARGS-aggrecan and TNF-α as well as urine levels of NTX-I and CTX-II. These markers remained high compared with those of controls with healthy knees at 2-year follow-up.

Collagen XII Deficiency Increases the Risk of Anterior Cruciate Ligament Injury in Mice

Anterior cruciate ligament (ACL) rupture is a common knee injury for athletes. Although surgical reconstruction is recommended for the treatment of ACL ruptures, 100% functional recovery is unlikely. Therefore, the discovery of risk factors for ACL ruptures may prevent injury. Several studies have reported an association between polymorphisms of the collagen XII gene COL12A1 and ACL rupture. Collagen XII is highly expressed in tendons and ligaments and regulates tissue structure and mechanical property. Therefore, we hypothesized that collagen XII deficiency may cause ACL injury. To elucidate the influence of collagen XII deficiency on ACL, we analyzed a mouse model deficient for Col12a1. Four- to 19-week-old male Col12a1-/- and wild-type control mice were used for gait analysis; histological and immunofluorescent analysis of collagen XII, and real-time RT-PCR evaluation of Col12a1 mRNA expression. The Col12a1-/- mice showed an abnormal gait with an approximately 2.7-fold increase in step angle, suggesting altered step alignment. Col12a1-/- mice displayed 20–60% ACL discontinuities, but 0% discontinuity in the posterior cruciate ligament. No discontinuities in knee ligaments were found in wild-type mice. Collagen XII mRNA expression in the ACL tended to decrease with aging. Our study demonstrates for the first time that collagen XII deficiency increases the risk of ACL injury.