Knee osteoarthritis (KOA) represents a clinical challenge due to poor potential for spontaneous healing of cartilage lesions. Several treatment options are available for KOA, including oral nonsteroidal anti-inflammatory drugs, physical therapy, braces, activity modification, and finally operative treatment. Intra-articular (IA) injections are usually used when the non-operative treatment is not effective, and when the surgery is not yet indicated. More and more studies suggesting that IA injections are as or even more efficient and safe than NSAIDs. Recently, research to improve intra-articular homeostasis has focused on biologic adjuncts, such as platelet-rich plasma (PRP). The catabolic and inflammatory intra-articular processes that exists in knee osteoarthritis (KOA) may be influenced by the administration of PRP and its derivatives. PRP can induce a regenerative response and lead to the improvement of metabolic functions of damaged structures. However, the positive effect on chondrogenesis and proliferation of mesenchymal stem cells (MSC) is still highly controversial. Recommendations from in vitro and animal research often lead to different clinical outcomes because it is difficult to translate non-clinical study outcomes and methodology recommendations to human clinical treatment protocols. In recent years, significant progress has been made in understanding the mechanism of PRP action. In this review, we will discuss mechanisms related to inflammation and chondrogenesis in cartilage repair and regenerative processes after PRP administration in in vitro and animal studies. Furthermore, we review clinical trials of PRP efficiency in changing the OA biomarkers in knee joint.

Tendons are connective tissue structures of paramount importance to human ability of locomotion. The understanding of their physiology and pathology is gaining importance as advances in regenerative medicine are being made today. So far, very few studies were conducted to extend the knowledge about pathology, healing response and management of tendon lesions. In this paper we summarize actual knowledge on structure, process of healing and ageing of the tendons. The structure of tendon is optimized for the best performance of the tissue. Despite the simplicity of the healing response, numerous studies showed, that the problems with full recovery are common and much more significant than we thought, that is why we discussed the issue of immobilization and mechanical stimulation during healing process. The phenomenon of tendons' ageing is poorly understood, although it seems to be a natural and painless process, it is completely different to degeneration in tendinopathy. Recent studies of biological treatment reported faster and optimal healing of the tendons when augmented by growth factors and stem cells. Despite advances in biology of tendons, management of their injuries is still a challenge for physicians, therefore further studies are required to improve treatment outcomes. Tendons are connective tissue structures of paramount importance to human ability of locomotion. The understanding of their physiology and pathology is gaining importance as advances in regenerative medicine are being made today. So far, very few studies were conducted to extend the knowledge about pathology, healing response and management of tendon lesions. In this paper we summarize actual knowledge on structure, process of healing and ageing of the tendons. The structure of tendon is optimized for the best performance of the tissue. Despite the simplicity of the healing response, numerous studies showed, that the problems with full recovery are common and much more significant than we thought, that is why we discussed the issue of immobilization and mechanical stimulation during healing process. The phenomenon of tendons' ageing is poorly understood, although it seems to be a natural and painless process, it is completely different to degeneration in tendinopathy. Recent studies of biological treatment reported faster and optimal healing of the tendons when augmented by growth factors and stem cells. Despite advances in biology of tendons, management of their injuries is still a challenge for physicians, therefore further studies are required to improve treatment outcomes.

To perform a feasibility study of dynamic sonography for the diagnosis of medial plica syndrome of the knee. The study design was approved by the university bioethics board, and all the participants gave informed consent. Inclusion criteria were a palpable medial band, history of painful aching, and giving way or locking, which limited the subject's activity for at least 6 months. Exclusion criteria were a history of trauma with hemarthrosis, previous knee surgery, and arthrosis detectable on radiographs. A prospective evaluation in 88 subjects (56 female subjects, 32 male subjects; mean age, 20 years; range, 7-47 years) who were suspected of having a medial plica and 91 knees was performed. Three sonographic criteria were assessed during patellar movement by using a 12-MHz 38-mm linear transducer: (a) continuous echo sliding over the medial femoral condyle during medial and lateral movement of the patella, (b) entry of the echo under the patella during medial movement of the patella, and (c) pain or discomfort during dynamic sonography. Arthroscopy was the reference standard. An asymptomatic control group consisting of 32 volunteers (mean age, 28 years; range, 10-52 years) and 60 knees was also assessed. Arthroscopy revealed 68 plicae with pathologic findings, 61 of which met all three sonographic criteria. Medial plicae with pathologic findings were absent in 23 knees; 19 plicae were correctly diagnosed by using sonography. Diagnostic accuracy was 88%, sensitivity was 90%, and specificity was 83%. In the asymptomatic control group, there were 37 knees without a plica echo, 16 knees with a plica echo that met one criterion, and seven knees that met two criteria. Dynamic sonography allows detection of abnormalities of medial plicae in the knee, with good sensitivity and specificity.

Cartilage lesions have a multifactorial nature, and genetic factors are their strongest determinants. As biochemical and genetic studies have dramatically progressed over the past decade, the molecular basis of cartilage pathologies has become clearer. Several homeostasis abnormalities within cartilaginous tissue have been found, including various structural changes, differential gene expression patterns, as well as altered epigenetic regulation. However, the efficient treatment of cartilage pathologies represents a substantial challenge. Understanding the complex genetic background pertaining to cartilage pathologies is useful primarily in the context of seeking new pathways leading to disease progression as well as in developing new targeted therapies. A technology utilizing gene transfer to deliver therapeutic genes to the site of injury is quickly becoming an emerging approach in cartilage renewal. The goal of this work is to provide an overview of the genetic basis of chondral lesions and the different approaches of the most recent systems exploiting therapeutic gene transfer in cartilage repair. The integration of tissue engineering with viral gene vectors is a novel and active area of research. However, despite promising preclinical data, this therapeutic concept needs to be supported by the growing body of clinical trials.

Background: The current standard of treatment of anterior cruciate ligament (ACL) is reconstruction (ACLR). This technique has some disadvantages: poor proprioception, donor site morbidity and the inability to restore joint kinematics. ACL repair could be an alternative treatment. The purpose of the study was to compare the stability and the function after ACL primary repair versus single-bundle ACLR. Methods: In a retrospective study, 12 patients underwent primary ACL repair with internal bracing, 15 patients underwent standard ACLR. Follow-up examinations were evaluated at up to 2 years postoperatively. One patient in the ACL repair group was lost to follow-up due to re-rupture. The absolute value of anterior tibial translation (ATT) and the side-to-side difference in the same patient (ΔATT) were evaluated using the GNRB arthrometer. The Lysholm knee scoring was obtained. Re-ruptures and other complications were recorded. Results: Anterior tibial translation (ATT) was significantly decreased in the ACL repair group compared with the ACLR group (5.31 mm vs. 7.18 mm, respectively; p = 0.0137). Arthrometric measurements demonstrated a mean side-to-side difference (ΔATT) 1.87 (range 0.2 to 4.9) mm significantly decreased compared to ACLR 3.36 (range 1.2–5.6 mm; p = 0.0107). The mean Lysholm score was 85.3 points in the ACL repair group and 89.9 in ACLR group. No significant differences between ACL repair and ACLR were found for the Lysholm score. There was no association between AP laxity and clinical outcomes. There were two complications in the internal bracing group: one patient had re-rupture and was treated by ACLR, another had limited extension and had arthroscopic debridement. Conclusions: Anterior tibial translation was significantly decreased after ACL repair. Additionally, the functional results after ACL repair with internal bracing were comparable with those after ACLR. It should be noted that the two complications occurred. The current study supports further development of ACL repair techniques.

Tendinopathy of the long head of the biceps tendon is a difficult medical issue. Its pathogenesis and etiology is multifactorial and unclear. Tendinopathy is thought to be primarily degenerative in nature, as tendons are characterized by impaired regeneration and healing. Thirty–five patients with preoperatively diagnosed tendinopathy of long head of the biceps tendon were referred to the Orthopedics Department. All patients underwent an arthroscopic–assisted biceps tenodesis or tenotomy. The intra-articular portion of the long head of the biceps tendon was obtained from each of the patients who underwent arthroscopy. A macroscopic and microscopic evaluation of biceps tendon samples revealed degeneration among all specimens. This study demonstrates the prevalence of the degeneration process and the presence of marginal inflammation process in tendinopathy of the long head of biceps tendon. The role, that inflammation process plays in tendinopathy is important in the early phase and gradually becomes secondary to the developing degeneration. The inflammatory cells, occasionally seen in pathological tendons, could be an evidence of re–injury and recent healing response.