The HeMoVal study protocol: a prospective international multicenter cohort study to validate cerebrospinal fluid hemoglobin as a monitoring biomarker for aneurysmal subarachnoid hemorrhage related secondary brain injury.

INTRODUCTION: Preclinical studies provided a strong rationale for a pathophysiological link between cell-free hemoglobin in the cerebrospinal fluid (CSF-Hb) and secondary brain injury after subarachnoid hemorrhage (SAH-SBI). In a single-center prospective observational clinical study, external ventricular drain (EVD) based CSF-Hb proved to be a promising biomarker to monitor for SAH-SBI. The primary objective of the HeMoVal study is to prospectively validate the association between EVD based CSF-Hb and SAH-SBI during the first 14 days post-SAH. Secondary objectives include the assessment of the discrimination ability of EVD based CSF-Hb for SAH-SBI and the definition of a clinically relevant range of EVD based CSF-Hb toxicity. In addition, lumbar drain (LD) based CSF-Hb will be assessed for its association with and discrimination ability for SAH-SBI. METHODS: HeMoVal is a prospective international multicenter observational cohort study. Adult patients admitted with aneurysmal subarachnoid hemorrhage (aSAH) are eligible. While all patients with aSAH are included, we target a sample size of 250 patients with EVD within the first 14 day after aSAH. Epidemiologic and disease-specific baseline measures are assessed at the time of study inclusion. In patients with EVD or LD, each day during the first 14 days post-SAH, 2 ml of CSF will be sampled in the morning, followed by assessment of the patients for SAH-SBI, co-interventions, and complications in the afternoon. After 3 months, a clinical follow-up will be performed. For statistical analysis, the cohort will be stratified into an EVD, LD and full cohort. The primary analysis will quantify the strength of association between EVD based CSF-Hb and SAH-SBI in the EVD cohort based on a generalized additive model. Secondary analyses include the strength of association between LD based CSF-Hb and SAH-SBI in the LD cohort based on a generalized additive model, as well as the discrimination ability of CSF-Hb for SAH-SBI based on receiver operating characteristic (ROC) analyses. DISCUSSION: We hypothesize that this study will validate the value of CSF-Hb as a biomarker to monitor for SAH-SBI. In addition, the results of this study will provide the potential base to define an intervention threshold for future studies targeting CSF-Hb toxicity after aSAH. STUDY REGISTRATION: ClinicalTrials.gov Identifier NCT04998370 . Date of registration: August 10, 2021.

Dynamic intraligamentary stabilization of anterior cruciate ligament repair: hardware removal has no effect on knee laxity at 2-year follow-up.

INTRODUCTION: Dynamic intraligamentary stabilization (DIS) stabilizes the knee joint during anterior cruciate ligament (ACL) healing. After 6 months, tibial hardware removal is offered to the patients if local discomfort at the implant site is present. AIM: This study compared knee laxity and functional scores 2 years after DIS between patients with and without hardware removal. It is hypothesized that it does not affect ACL healing. MATERIALS AND METHODS: The study retrospectively analyzed prospectively collected data from 173 patients with either hardware removal (n = 47) or no additional intervention (n = 126). Inverse probability of treatment weighting using the propensity score was applied to balance the groups for baseline characteristics. The primary outcome was the side-to-side difference in knee laxity measured with the rolimeter at manual maximum force (Δ-Lachman). Secondary outcomes were the pivot-shift test and subjective scores. RESULTS: Mean age was 34 years in both groups, and female gender was 47% (hardware removal group) and 50% (control group), respectively. No significant differences were found for Δ-Lachman (p = 0.09), pivot-shift test (p = 0.41), and subjective scores (p > 0.10) two years after DIS. CONCLUSION: Knee laxity 2 years after DIS in patients with tibial hardware removal and patients without hardware removal was not significantly different. The groups were also similar regarding all the assessed functional scores. This study confirms the hypothesis that the healing ACL resumes its stabilizing role, and the hardware can be removed beginning 6 months after surgery without adverse consequences for joint stability. LEVEL OF EVIDENCE: Case-control study, Level III.

Correction to: Surgeon experience with dynamic intraligamentary stabilization does not influence risk of failure.

The original version of this article unfortunately contains mistake in Table 4.

Correction to: Patient and surgical characteristics that affect revision risk in dynamic intraligamentary stabilization of the anterior cruciate ligament.

The original version of this article unfortunately contained a mistake.

Reinterventions after dynamic intraligamentary stabilization in primary anterior cruciate ligament repair.

BACKGROUND: The goal of this study was to perform an in-depth analysis of the frequency and cause of secondary interventions subsequent to primary anterior cruciate ligament (ACL) repair with dynamic intraligamentary stabilization (DIS). METHODS: Between July 2009 and June 2014, 455 patients underwent DIS treatment. The minimum follow-up was 21months (mean 28months, range 21-64months). RESULTS: A total of 215 (48.2%) reinterventions were performed in 190 (42.6%) patients. One-hundred and seventy-six (39.4%) were non-revision reinterventions, and 39 (8.7%) were revision ACL reconstructions. Re-arthroscopies included 26 (5.8%) scar tissue debridements with hardware removal due to range of motion deficits, 14 (3.1%) partial meniscectomies, four (0.9%) meniscal sutures, and four (0.9%) arthroscopies due to crepitation or knee pain. Minor non-revision reinterventions performed under analgosedation consisted of 97 (21.7%) hardware removals, 20 (4.5%) hardware removals with manipulations under anesthesia, and four manipulations under anesthesia alone (0.9%). CONCLUSIONS: In our study, the revision rate was within the range of published results after ACL reconstructions. In over 90% of patients, the native ACL was preserved with no need for a secondary reconstruction. Most of the non-revision reinterventions were minor and included hardware removals and manipulations under anesthesia. The re-arthroscopy rate was lower than that after ACL reconstruction with fewer secondary meniscal sutures and partial meniscectomies. Early treatment of meniscal tears may be one crucial benefit of ACL repair with DIS.

Surgeon experience with dynamic intraligamentary stabilization does not influence risk of failure.

PURPOSE: Studies on dynamic intraligamentary stabilization (DIS) of acute anterior cruciate ligament (ACL) ruptures reported failure rates similar to those of conventional ACL reconstruction. This study aimed to determine whether surgeon experience with DIS is associated with revision rates or patient-reported outcomes. The hypothesis was that more experienced surgeons achieved better outcomes following DIS due to substantial learning curve. METHODS: The authors prospectively enrolled 110 consecutive patients that underwent DIS and evaluated them at a minimum of 2 years. The effects of independent variables (surgeon experience, gender, age, adjuvant procedures, tear location, preinjury Tegner score, time from injury to surgery, and follow-up) on four principal outcomes (revision ACL surgery, any re-operation, IKDC and Lysholm score) were analyzed using univariable and multivariable regressions. RESULTS: From the 110 patients enrolled, 14 patients (13%) were lost to follow-up. Of the remaining 96 patients, 11 underwent revision ACL surgery, leaving 85 patients for clinical assessment at a mean of 2.2 ± 0.4 years (range 2.0-3.8). Arthroscopic reoperations were performed in 26 (27%) patients, including 11 (11%) revision ACL surgeries. Multivariable regressions revealed: (1) no associations between the reoperation rate and the independent variables, (2) better IKDC scores for 'designer surgeons' (b = 10.7; CI 4.9-16.5; p < 0.001), higher preinjury Tegner scores (b = 2.5, CI 0.8-4.2; p = 0.005), and younger patients (b = 0.3, CI 0.0-0.6; p = 0.039), and (3) better Lysholm scores for 'designer surgeons' (b = 7.8, CI 2.8-12.8; p = 0.005) and preinjury Tegner score (b = 1.9, CI 0.5-3.4; p = 0.010). CONCLUSION: Surgeon experience with DIS was not associated with rates of revision ACL surgery or general re-operations. Future, larger-scaled studies are needed to confirm these findings. Patients operated by 'designer surgeons' had slightly better IKDC and Lysholm scores, which could be due to better patient selection and/or positively biased attitudes of both surgeons and patients. LEVEL OF EVIDENCE: Level II, prospective comparative study.

Dynamic Posterior Stabilization versus Posterior Lumbar Intervertebral Fusion: A Matched Cohort Study Based on the Spine Tango Registry.

PURPOSE: The primary aim of dynamic stabilization is to stabilize the spine and preserve function without overstressing adjacent segments, which is a potential risk of fusion surgery. However, direct comparative analyses of the two approaches are still limited, and little is known about the association of patient-reported outcomes with these treatment options. OBJECTIVE: To compare the clinical outcomes of dynamic posterior stabilization using the DSS Stabilization System (Paradigm Spine, LLC, New York, New York, United States) versus posterior lumbar intervertebral fusion (PLIF) based on data from a spine registry. We hypothesized that patient-reported outcomes of DSS are not inferior to those of PLIF. METHODS: We identified 202 DSS and 269 PLIF patients with lumbar degenerative disease with a minimum 2-year follow-up. A 1:1 propensity score-based matching was applied to balance the groups for various patient characteristics. The primary outcome was the change in the patient-reported Core Outcome Measures Index (COMI; a 0-10 scale) score. RESULTS: The matching resulted in 77 DSS-PLIF pairs (mean age: 67 years; average COMI follow-up: 3.3 years) without residual significant differences in baseline characteristics. The groups showed no difference in improved COMI score (p = 0.69), as well as in back (p = 0.51) and leg pain relief (p = 0.56), blood loss (p = 0.12), and complications (p > 0.15). Fewer repeat surgeries occurred after DSS (p = 0.01). The number of repeat surgeries per 100 observed person-years was 0.8 and 2.9 in DSS and in PLIF patients, respectively. Furthermore, shorter surgery time (p < 0.001) and longer hospital stays (p = 0.03) were observed for DSS cases. CONCLUSION: In a midterm perspective, DSS may be a viable alternative to PLIF because both therapies result in similar COMI score improvement. Advantages of DSS may be shorter duration of surgery and fewer repeat surgeries. However, more than half of DSS patients did not find a match with a PLIF patient, suggesting that the patient profiles may be different. Further multicenter studies are needed to better understand the most appropriate indication for each therapy.

Patient and surgical characteristics that affect revision risk in dynamic intraligamentary stabilization of the anterior cruciate ligament.

PURPOSE: Failure of dynamic intraligamentary stabilization (DIS) that requires revision surgery of the anterior cruciate ligament (ACL) has not been studied. The aim of this study was to investigate the incidence of revision ACL surgery, and the patient characteristics and surgery-related factors that are associated with an increased risk of ACL revision after DIS. METHODS: This study analysed a prospective, consecutively documented single-centre case series using standardized case report forms over a 2.5-year follow-up period. The primary endpoint was revision ACL surgery. We used Kaplan-Meier analysis to examine the revision-free survival time, and a multiple logistic regression model of potential risk factors including age, sex, BMI, smoking status, previous contralateral ACL injury, Tegner activity score, interval to surgery, rupture pattern, hardware removal, and postoperative side-to-side difference in knee laxity. Relative risk was calculated for subgroups of significant risk factors. RESULTS: In total, 381 patients (195 male) with a mean age of 33 ± 12 years were included in the analysis. The incidence of revision ACL surgery was 30/381 (7.9%). Younger age (p = 0.001), higher Tegner activity score (p = 0.003), and increased knee laxity (p = 0.015) were significantly associated with revision ACL surgery. The increased relative risk for patients who were less than 24 years old, participated in activities at a Tegner level >5 points, or had >2 mm of side-to-side difference in knee laxity was 1.6, 3.7, and 2.3, respectively. CONCLUSION: Young age, high level of sport activity, and high knee laxity observed in follow-up examinations increased the likelihood for revision surgery after DIS. Patients undergoing DIS should be informed of their potentially increased risk for therapy failure and carefully monitored during recovery. LEVEL OF EVIDENCE: Case series, Level IV.

Dynamic intraligamentary stabilization versus conventional ACL reconstruction: A matched study on return to work.

PURPOSE: The dynamic intraligamentary stabilization (DIS) technique is based on a different treatment approach than ACL reconstruction in that it intends to promote self-healing of the ligament. It is only recommended for acute injuries (<21days). The purpose of the present study was to compare DIS and ACLR with respect to the extent of work incapacity, revision rates, secondary arthroscopies, and treatment costs during recovery. METHODS: The study was a post-hoc analysis of prospectively collected data in the Swiss National Accident Insurance Fund (SUVA) database. All registered DIS cases treated until 31 December 2012 were included in the study. ACLR cases were matched to DIS cases using a propensity score approach and analysed in a follow-up period of 2 years after injury. Paired Student's T-test and the Chi-square test were used to compare the outcome measures. RESULTS: All 53 DIS patients were matched to an ACLR pair. The mean time period from injury to surgery was 14days for DIS and 50days for ACLR (p<0.001). Overall work incapacity was 13% for DIS and 17% for ACLR resulting in a difference of nearly 1 month of absence from work (p=0.03). The course of postoperative work incapacity was very similar between the groups, while the work incapacity prior to surgery lower in the DIS group. We found no difference in treatment costs, secondary arthroscopies and revision rates. CONCLUSION: DIS patients benefited from nearly one month shorter absence from work than ACLR patients. This difference is likely related to the early surgical timing that is recommended for DIS. Since no differences were found between DIS and ACLR in terms of treatment costs, secondary arthroscopies and revision rates, the study supports the choice of DIS as an additional treatment option for acute ACL injuries. Further comparative studies are proposed to improve the evidence about optimal timing and best practice in ACL treatment.

Functional recovery following primary ACL repair with dynamic intraligamentary stabilization.

BACKGROUND: Recently, a new technique, dynamic intraligamentary stabilization (DIS) was introduced for the acute repair of ACL ruptures. The purpose of this study was to report the functional recovery for patients undergoing acute anterior cruciate ligament (ACL) repair alongside DIS. METHODS: Forty five patients sustaining acute ACL rupture and treated with DIS repair were retrospectively evaluated. Limb symmetry index of the hop test as well as knee function by means of range of motion, knee swelling, pain and maximum strength were evaluated. Following completion of the rehabilitation program, the difference in anterior-posterior translation (Δ-AP Translation), IKDC, Tegner score (TAS) was additionally analyzed. RESULTS: Forty five (13 females, 32 males) patients were included in the study. Mean age was 26years (range 18 to 54years). Median time to successfully complete hop test was 22.0weeks (range 11 to 32weeks) postoperatively. Median limb symmetry index 91.6%±8.3%. Median delta anterior-posterior translation compared to the healthy side was plus 0.0mm±1.6mm. Median IKDC was 89.5±6.5. Mean Tegner score (TAS) at 12months of follow-up was seven (range four to nine). Three patients suffered a rerupture during the first 12 postoperative months. CONCLUSIONS: DIS technique with proper rehabilitation following acute ACL rupture provides successful functional recovery and low rerupture rate at one-year follow-up.

Beta-alanine supplementation improves jumping power and affects severe-intensity performance in professional alpine skiers.

INTRODUCTION: Supplementation with beta-alanine may have positive effects on severe-intensity, intermittent, and isometric strength-endurance performance. These could be advantageous for competitive alpine skiers, whose races last 45 to 150 s, require metabolic power above the aerobic maximum, and involve isometric muscle work. Further, beta-alanine supplementation affects the muscle force-frequency relationship, which could influence explosiveness. We explored the effects of beta-alanine on explosive jump performance, severe exercise energy metabolism, and severe-intensity ski-like performance. METHODS: Nine male elite alpine skiers consumed 4.8 g/d beta-alanine or placebo for 5 weeks in a double-blind fashion. Before and after, they performed countermovement jumps (CMJ), a 90-s cycling bout at 110% VO2max (CLT), and a maximal 90-s box jump test (BJ90). RESULTS: Beta-alanine improved maximal (+7 ± 3%, d = 0.9) and mean CMJ power (+7 ± 2%, d = 0.7), tended to reduce oxygen deficit (-3 ± 8%, p = .06) and lactate accumulation (-12 ± 31%) and enhance aerobic energy contribution (+1.3 ± 2.9%, p = .07) in the CLT, and improved performance in the last third of BJ90 (+7 ± 4%, p = .02). These effects were not observed with placebo. CONCLUSIONS: Beta-alanine supplementation improved explosive and repeated jump performance in elite alpine skiers. Enhanced muscle contractility could possibly explain improved explosive and repeated jump performance. Increased aerobic energy production could possibly help explain repeated jump performance as well.