Patient-specific instrumentation in total knee arthroplasty: a review of the current literature.

Total knee arthroplasty (TKA) is one of the most frequently performed interventions in the field of Orthopaedic surgery. Over the last decades the implantation technique has improved continuously. The majority of patients is satisfied with the clinical outcome of TKA. However in various clinical follow-ups, up to 20% of unsatisfied patients can be observed. Periprosthetic infection and aseptic loosening seem to be the most common reasons for failure. Malalignment has been discussed as a cause of aseptic loosening and often leads to revision surgery. In order to increase the precision of implant positioning and alignment, new technologies such as patient-specific instrumentation (PSI) have been developed. Since the introduction of PSI, multiple clinical studies have been performed analyzing the clinical and radiological outcome of TKA with PSI technique. This review covers the recent literature of PSI in respect to surgical accuracy, clinical outcome, time- and cost-effectiveness.

Complication rate after operative treatment of three- and four-part fractures of the proximal humerus: locking plate osteosynthesis versus proximal humeral nail.

PURPOSE: There is still disagreement regarding the optimal surgical treatment of three- and four-part fractures of the proximal humerus. The aim of this monocentric, retrospective study was to compare the complication rate of internal fixation with a locking plate versus proximal humeral nailing after a one-year follow-up. METHODS: From 2005 to 2016, 292 patients suffered a fracture of the proximal humerus and were treated surgically at our level-I trauma center. According to the inclusion criteria, 50 patients were included in this study: 19 of these (11 three-part fractures and 8 four-part fractures) were treated with a proximal humeral nail (HN) and 31 (12 three-part fractures and 19 four-part fractures) with a locking plate (LP) osteosynthesis. Classification was performed according to the Hertel classification. At a 1-year follow-up, the complication rate of the two treatment methods was compared. RESULTS: Twenty patients (40%) suffered at least one complication. Of these, six patients (12%) were treated with a HN and 14 (28%) with a LP (p = 0.39). The most frequent complication was screw perforation (22%), followed by non-union (16%). Humeral head necrosis (10%) occurred only in the LP cohort. One wound infection occurred in a patient treated with a HN. Four-part fractures were treated more frequently with a LP. However, the difference was non-significant in this sample (p = 0.186). CONCLUSIONS: The results of our study provide some evidence that in terms of complication rate, both treatment options are comparable for internal fixation of three- and four-part fractures of the proximal humerus. The type of fracture seems to be decisive for the choice of implant.