Background Sarcomas in or contaminating the knee are rare but extremely challenging to treat. Complete resection of the joint is necessary, and often the entire extensor mechanism is removed as well. Reconstruction of the knee is challenging, and the resulting function may be compromised. Description of technique We describe a surgical technique of extraarticular resection of the knee while preserving the extensor mechanism combined with prosthetic reconstruction. The medial and lateral retinaculum is prepared such that it allows extraarticular placement of K-wires that are driven through the patella and the proximal tibia, serving as in situ guides for the osteotomies. Patients and Methods We retrospectively reviewed 11 patients with sarcomas contaminating the knee. The minimum followup was 14 months (mean, 38 months; range, 14-80 months). Results At last followup patients had a mean flexion of 88°(range, 65°-120°). We observed no complications related to the extensor mechanism, and there was one local recurrence.

During periacetabular osteotomy (PAO) the acetabulum is reorientated and the correction monitored by one or more anteroposterior pelvic radiographs. Obtaining these images is time consuming and requires additional technical and personal resources. Such disadvantages could be overcome with the use of fluoroscopy. However, information obtained from fluoroscopy should have the same quality when compared to standard pelvic radiography. Our purpose was to define a suitable fluoroscopy setup and compare the information obtained from the fluoroscopic images to that obtained from a traditional anteroposterior pelvic radiograph. In a consecutive series of 22 patients the acetabular fragment was monitored by a defined intraoperative fluoroscopy setup in addition to a pelvic radiograph. The images were analyzed in random order utilizing common parameters to judge the quality of acetabular orientation. Agreement between the two images was assessed using kappa statistics and compared to the intra-observer reliability obtained from an independent experienced hip surgeon reading the same set of pelvic radiographs on two occasions. In 5 patients the radiation exposure during both fluoroscopy and standard AP pelvic radiography was measured and compared. Agreement of angular measurements of acetabular coverage and version as well as qualitative parameters of acetabular orientation and position between fluoroscopy and pelvic radiographs was at least equal to the intra-observer agreement of an independent experienced hip surgeon reviewing the pelvic radiographs alone. Significantly less radiation exposure was recorded with the use of fluoroscopy when compared to traditional pelvic radiography. We conclude that the use of intraoperative pelvic radiographs during PAO procedures can be replaced by fluoroscopy without quality impairment.

Background. Long-term survival of total knee arthroplasty (TKA) is mainly determined by optimal positioning of the components and prosthesis alignment. Implant positioning can be optimized by computer assisted surgery (CAS). Patient specific cutting blocks (PSCB) seem to have the potential to improve component alignment compared to the conventional technique and to be comparable to CAS. Methods. 113 knees were selected for PSI and included in this study. Pre- and postoperative mechanical axis, represented by the hip-knee-angle (HKA), the proximal tibial angle (PTA), the distal femoral angle (DFA), and the tibial slope (TS) were measured and the deviation from expected ideal values was calculated. Results. With a margin of error of ±3°, success rates were 81.4% for HKA, 92.0% for TPA, and 94.7% for DFA. With the margin of error for alignments extended to ±4°, we obtained a success rate of 92.9% for the HKA, 98.2% for the PTA, and 99.1% for the DFA. The TS showed postoperative results of 2.86 ± 2.02° (mean change 1.76 ± 2.85°). Conclusion. PSCBs for TKA seem to restore the overall leg alignment. Our data suggest that each individual component can be implanted accurately and the results are comparable to the ones in CAS.