Delayed Meniscus Repair Lowers the Functional Outcome of Primary ACL Reconstruction

Background: Our purpose was to evaluate whether the time of intervention and the type of meniscus surgery (repair vs. partial meniscectomy) play a role in managing anterior cruciate ligament (ACL) reconstructions with concurrent meniscus pathologies. Methods: We performed a prospective cohort study which differentiated between early and late ACL reconstructions with a cut-off at 3 months. Patients were re-evaluated after 2 years. Results: Thirty-nine patients received an operation between 2–12 weeks after the injury, and thirty patients received the surgery between 13–28 weeks after trauma. The strongest negative predictive factor of the International Knee Documentation Committee subjective knee form in a hierarchical regression model was older age (ß = −0.49 per year; 95% CI [−0.91; −0.07]; p = 0.022; partial R2 = 0.08)). The strongest positive predictive factor was a higher preoperative Tegner score (ß = 3.6; 95% CI [0.13; 7.1]; p = 0.042; partial R2 = 0.07) and an interaction between meniscus repair surgery and the time of intervention (ß = 27; 95% CI [1.6; 52]; p = 0.037; partial R2 = 0.07), revealing a clinical meaningful difference as to whether meniscus repairs were performed within 12 weeks after trauma or were delayed. There was no difference whether partial meniscectomy was performed early or delayed. Conclusions: Surgical timing plays a crucial role when surgeons opt for a meniscus repair rather than for a meniscectomy

What is the relationship of fear avoidance to physical function and pain intensity in injured athletes?

Background Fear avoidance can play a prominent role in maladaptive responses to an injury. In injured athletes, such pain-related fear or fear avoidance behavior may have a substantial influence on the recovery process. Specifically, it may explain why some are able to reach their preinjury abilities, whereas others are unable to return to sport. Questions/purposes (1) Is fear avoidance in athletes associated with decreased physical function after injury? (2) To what degree is fear avoidance associated with athletes’ pain intensity? Methods In a cross-sectional study, we recruited injured athletes—defined as patients with sports-related injury, weekly engagement in sport activities, participation in competitive events as part of a team or club, self-identification as an athlete, and a desire to return to sport after recovery—from an orthopaedic sports medicine center at a major urban university hospital. Of 130 approached patients, 102 (84% men; mean 6 SD age 25 6 8.5 years) met the inclusion criteria. Participants completed a demographic questionnaire, the Athlete Fear Avoidance Questionnaire, which assesses injury-related fear and avoidance behavior specifically in an athletic population, the Pain Catastrophizing Scale, the Hospital Anxiety and Depression Scale, and two Patient-Reported Outcomes Measurement Information System measures: Physical Function Computerized Adaptive Testing (CAT) and Pain Intensity CAT. Results After controlling for age, injury region (upper versus lower extremity), catastrophic thinking, and emotional distress, we found that an increase in athletes’ fear avoidance was associated with a decrease in physical function (b = -0.32; p = 0.002). The model explained 30% of the variation in physical function with 7.3% explained uniquely by fear avoidance. After controlling for initial appointment/ followup, surgery for the current condition, multiple pain conditions, history of prior sport-related injury/surgery, pain medication prescription, catastrophic thinking, and emotional distress, athletes’ fear avoidance was not associated with pain (b = -0.14; p = 0.249).Themodel explained 40%of the variation in pain intensity and pain catastrophizing (b = 0.30; p = 0.001) uniquely explained 7.1% of this variation. Conclusions In injured athletes, fear avoidance is independently associated with decreased physical function, whereas pain catastrophizing is associated with high pain intensity. Both level of an athlete’s fear avoidance and catastrophic thinking about pain should be accounted for in clinical interventions aimed at helping athletes improve recovery and return to sport. Level of Evidence Level II, prognostic study

Long-term in vivo degradation of Mg–Zn–Ca elastic stable intramedullary nails and their influence on the physis of juvenile sheep

The use of bioresorbable magnesium (Mg)-based elastic stable intramedullary nails (ESIN) is highly promising for the treatment of pediatric long-bone fractures. Being fully resorbable, a removal surgery is not required, preventing repeated physical and psychological stress for the child. Further, the osteoconductive properties of the material support fracture healing. Nowadays, ESIN are exclusively implanted in a non-transphyseal manner to prevent growth discrepancies, although transphyseal implantation would often be required to guarantee optimized fracture stabilization. Here, we investigated the influence of trans-epiphyseally implanted Mg–Zinc (Zn)–Calcium (Ca) ESIN on the proximal tibial physis of juvenile sheep over a period of three years, until skeletal maturity was reached. We used the two alloying systems ZX10 (Mg-1Zn-0.3Ca, in wt%) and ZX00 (Mg-0.3Zn-0.4Ca, in wt%) for this study. To elaborate potential growth disturbances such as leg-length differences and axis deviations we used a combination of in vivo clinical computed tomography (cCT) and ex vivo micro CT (μCT), and also performed histology studies on the extracted bones to obtain information on the related tissue. Because there is a lack of long-term data regarding the degradation performance of magnesium-based implants, we used cCT and μCT data to evaluate the implant volume, gas volume and degradation rate of both alloying systems over a period of 148 weeks. We show that transepiphyseal implantation of Mg–Zn–Ca ESIN has no negative influence on the longitudinal bone growth in juvenile sheep, and that there is no axis deviation observed in all cases. We also illustrate that 95 % of the ESIN degraded over nearly three years, converging the time point of full resorption. We thus conclude that both, ZX10 and ZX00, constitute promising implant materials for the ESIN technique.ISSN:2772-9508ISSN:2772-951

Long-term in vivo degradation behavior and near-implant distribution of resorbed elements for magnesium alloys WZ21 and ZX50

We report on the long-term effects of degrading magnesium implants on bone tissue in a growing rat skeleton using continuous in vivo micro-Computed Tomography, histological staining and Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS). Two different magnesium alloys—one rapidly degrading (ZX50) and one slowly degrading (WZ21)—were used to evaluate the bone response and distribution of released Mg and Y ions in the femur of male Sprague-Dawley rats. Regardless of whether the alloy degrades rapidly or slowly, we found that bone recovers restitutio ad integrum after complete degradation of the magnesium implant. The degradation of the Mg alloys generates a significant increase in Mg concentration in the cortical bone near the remaining implant parts, but the Mg accumulation disappears after the implant degrades completely. The degradation of the Y-containing alloy WZ21 leads to Y enrichment in adjacent bone tissues and in newly formed bone inside the medullary space. Locally high Y concentrations suggest migration not only of Y ions but also of Y-containing intermetallic particles. However, after the full degradation of the implant the Y-enrichment disappears almost completely. Hydrogen gas formation and ion release during implant degradation did not harm bone regeneration in our samples.ISSN:1742-7061ISSN:1878-756