Influence of rupture patterns of the medial patellofemoral ligament (MPFL) on the outcome after operative treatment of traumatic patellar dislocation.

PURPOSE: Patellar dislocation usually occurs to the lateral side, leading to ruptures of the medial patellofemoral ligament (MPFL) in about 90 % of all cases. Reliable prognostic factors for the stability of the patellofemoral joint after MPFL surgery and satisfaction of the patient have not been established as yet. METHODS: This multicentric study retrospectively included 40 patients with a mean age of 22.4 ± 8.1 years (range 9-48) from 5 German Trauma Departments with first-time traumatic patellar dislocation and operative treatment. Surgery was limited to soft tissue repairs, and a preoperative magnetic resonance imaging (MRI) was performed in all cases. Evaluation of the MRI included sulcus angle, dysplasia of the trochlea, depth and facet asymmetry of the trochlea, Insall-Salvati index, Tibial tuberosity to trochlear groove (TTTG) distance, and rupture patterns of the MPFL. Patients were interrogated after 2 years about recurrent dislocation, satisfaction, and the Kujala score. RESULTS: Trochlea facet asymmetry was significantly lower in patients with redislocation (23.5 ± 18.8) than in patients without redislocation (43.1 ± 16.5, p = 0.03). Patients with a patellar-based rupture were significantly younger (19.5 ± 7.2 years) than patients without patellar-based rupture (25.4 ± 8.1 years, p < 0.02). Patients with femoral-based ruptures were significantly older (25.7 ± 9.2 years) than patients without femoral-based rupture (19.7 ± 6.1 years, p < 0.02), and had a significantly higher TTTG distance (10.2 ± 6.9 vs. 4.5 ± 5.5, p < 0.02). Patients with incomplete ruptures of the MPFL had a significantly lower Insall-Salvati index (1.2 ± 0.2 vs. 1.4 ± 0.2, p = 0.05). The Kujala score in patients with redislocations was significantly lower (81.0 ± 10.5 points) than in patients without redislocation (91.9 ± 9.2 points, p < 0.02). CONCLUSION: Younger patients more often sustain patellar-based ruptures following first-time traumatic patella dislocation, while older patients more often sustain femoral-based ruptures of the MPFL. Incomplete MPFL ruptures are correlated with lower Insall-Salvati indices. Low trochlear facet asymmetry is correlated with higher rates of redislocation. These results may be of relevance for the operative and postoperative treatment in the future. LEVEL OF EVIDENCE: Prognostic study, Level IV.

α-Adrenergic receptor function, arousal and sleep: mechanisms and therapeutic implications.

Noradrenergic (NE) neurotransmission and particularly α-adrenergic receptor function has been identified as a critical component of the sleep/wake regulation in animals and humans. This work (i) provides an update on the impact of NE neurotransmission on the sleep/wake regulation, (ii) summarizes the effects of α-receptor agonists and antagonists on arousal and sleep in animals and healthy humans, and (iii) reviews the current body of evidence for the effectiveness and safety of these compounds in the treatment of clinical conditions characterized by alterations of arousal or sleep, including attention deficit and hyperactivity disorder (ADHD), post-traumatic stress disorder (PTSD), borderline personality disorder and primary sleep disorders. This systematic evaluation of the potential and limitations of the effects of α-adrenergic compounds might promote novel inroads for the treatment of these highly prevalent clinical conditions.

Effects of continuous perfusion on human bone marrow stromal cells seeded on a decellularized bovine Achilles tendon matrix.

Ruptures of tendons and ligaments are a widely common injury in traumatology. The aim of the study was the development of a substitute tissue for such defects by methods of tissue-engineering. Human bone marrow stromal cells (hBMSC) were seeded on a decellularized bovine Achilles tendon and cultivated in a special bioreactor. We examined the influence of continuous perfusion on proliferation and biomechanical stability compared to static cultivation. Samples were taken on day 0, 7 and 14. Decellularized tendons were chosen as a negative control. Cell quantity was measured by the MTS-Test. Histology was analyzed by Haematoxylin-Eosin- and Pentachrome-coulouring. The cultivated tendons were tested biomechanically compared with the decellularized control group. MTS-Test revealed an increase of cell count of 7% in the static group and a decrease of 9% in the perfusion group. The perfusion group showed a stronger network of the fibroblasts and a higher amount of produced extracellular matrix. Biomechanical testing revealed significantly higher stability in the decellularized control group. This trial shows up new possibilities of managing defects of tendons and ligaments. The continuous perfusion in a bioreactor can improve the structure of the matrix seeded with hBMSC.

No effect in combining chondrogenic predifferentiation and mechanical cyclic compression on osteochondral constructs stimulated in a bioreactor.

Traumatic and degenerative osteochondral lesions are a common problem in orthopaedic surgery. The concept of tissue engineering represents the possibility of a promising therapeutical approach. The purpose of this study has been to improve the characteristics of osteochondral grafts consisting of a human certified collagen I-bone hybrid matrix seeded with human bone marrow stromal cells and stimulated in a custom-made biomechanoreactor. This study was undertaken as a follow-up to our prior studies. Based on our established system, we added chondrogenic growth factors (IGF-1 and TGF-beta(2)) and evaluated their effect on chondrogenic differentiation. Constructs were stimulated for 14, 21 and 28 days respectively by different protocols, including cyclic mechanical stimulation, hormonal stimulation or a combination of both. More than 70% of the cells were viable throughout the entire experimental period. Histological analysis revealed a homogeneous distribution of cells in a cartilage-like matrix organization. Immunohistological collagen II staining was positive irrespective of stimulation manner and time. Levels of DNA and glycosaminoglycans, having been normalized to DNA, did not change. Analysis of the biomechanical stiffness after 14 days showed increased stiffness in the hormonally and mechanically stimulated group compared to the static group. Stimulation time did not have a significant influence. The media supplements to foster the quality of the tissue tested here did not show any progress in our system. We conclude that cyclic compression enhances matrix stiffness, but stimulation time should be kept short and growth factors should be left out in this system with regard to clinical applicability and financial concerns.