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.

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.

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 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.

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.