III.

OCT is an effective therapy even for large chondral defects >3 cm(2). By filling the defects with TruFit implants, no clinical improvements could be found since the donor site morbidity was already low anyway. However, the regeneration of defects filled with TruFit implants took more than 2 years.

Arthroscopic irrigation with stage-related debridment of all 6 recesses in combination with antibiotic therapy is the standard procedure for knee joint infections when there is no arthroplasty. Open surgery with debridement of infected bone tissue is indicated in patients with stage IV according to Gächter. Decisive for good results is an early intervention.

Up to 30% of patients after distal radius fractures suffer from ulnar-sided wrist pain. 1 This is manifested in the form of wrist pain, restricted movement, weakness, and instability, even after correct reduction of the fracture and bony union. The integrity of the distal radioulnar joint (DRUJ) is necessary for stability and load transfer from the forearm to the wrist. [2][3][4] Osteoarthritis of the DRUJ may occur after trauma due to a bony deformity, a ligamentous injury, or combination of both. 1,5,16 In the surgical treatment of osteoarthritis, "salvage operations" are often necessary, in which the ulnar head is resected partially or completely. 7-10 Numerous clinical studies have demonstrated a reduction of painful clinical symptoms for all these techniques. 11-14 Biomechanically, even a partial resection of the distal ulna destabilizes the wrist, and clinically, it may lead to instability of the distal ulnar stump and the radius. 15,16 Distal radioulnar impingement occurs because the distal support of the radius for rotation and the "cam effect" of the distal ulna have been ablated. As a result, instability of the DRUJ may again lead to restriction of motion and strength as well as to increased pain. [17][18][19] To reduce DRUJ instability, various "soft tissue stabilization operations" have been developed. The most common techniques are the pronator quadratus-interposition flap (Johnson procedure) 20 and the extensor carpi ulnaris (ECU)-flexor carpi ulnaris (FCU) tenodesis (Breen-Jupiter tenodesis). [21][22][23] Biomechanical studies, however, show that these procedures do not provide adequate stabilization of the distal ulna. 24 Ulnar head prostheses have also been developed to restore the integrity of the DRUJ, which has been shown experimentally 6 and clinically. [25][26][27][28] Keywords ► distal radioulnar joint (DRUJ) ► osteoarthritis ► arthroplasty ► ulnar head resection ► ulnar head prosthesis AbstractA stable distal radioulnar joint (DRUJ) is mandatory for the function and load transmission in the wrist and forearm. Resectional salvage procedures such as the Darrach procedure, Bowers arthroplasty, and Sauvé-Kapandji procedure include the potential risk of radioulnar instability and impingement, which can lead to pain and weakness. Soft tissue stabilizing techniques have only limited success rates in solving these problems. In an attempt to stabilize the distal forearm mechanically following ulnar head resection, various endoprostheses have been developed to replace the ulnar head. The prostheses can be used for secondary treatment of failed ulnar head resection, but they can also achieve good results in the primary treatment of osteoarthritis of the DRUJ. Our experience consists of twenty-five patients (follow-up 30 months) with DRUJ osteoarthritis who were treated with an ulnar head prosthesis, with improvement in pain, range of motion, and grip strength. An ulnar head prosthesis should be considered as a treatment option for a painful DRUJ.

Minimally invasive and arthroscopic procedures have become an integral part of orthopedics and arthroscopy of the knee in particular has extensively evolved during recent years. Therefore, the purpose of this article is to show the indications and possibilities and also the limitations of arthroscopy-assisted fracture fixation of the knee joint. Based on the literature and our own experiences we consider the following indications for arthroscopy-assisted fracture fixation in the knee to be appropriate: 1) simple fractures of the tibial plateau, depression fractures of the tibial plateau and simple fractures of the patella, 2) arthroscopic control of reconstruction of the articular surface in complex fractures, 3) bony avulsions of the posterior or anterior cruciate ligament, 4) osteochondral flakes, 5) therapy of concomitant intra-articular lesions in fractures of the knee joint and 6) arthroscopy in posttraumatic situations. The various indications are discussed in relation to the current literature and on the basis of case reports. Arthroscopy is not only an assisting and helpful instrument in the therapy of fractures of the knee joint but in some cases it is also indispensable to guarantee optimal fracture management.