We used (31)P and (13)C solid-state nuclear magnetic resonance (NMR) spectroscopy to detect and analyze the major organic and inorganic components (collagen type I and bioapatite) in natural rabbit bone and beta-tricalcium phosphate implants loaded with osteogenically differentiated mesenchymal stem cells. High-resolution solid-state NMR spectra were obtained using the magic-angle spinning (MAS) technique. The (31)P NMR spectra of bone specimens showed a single line characteristic of bone calcium phosphate. (13)C cross-polarization (CP) MAS NMR spectra of bone exhibited the characteristic signatures of collagen type I with good resolution for all major amino acids in collagen. Quantitative measurements of (13)C-(1)H dipolar couplings indicated that the collagen segments are very rigid, undergoing only small amplitude fluctuations with correlation times in the nanosecond range. In contrast, directly polarized (13)C MAS NMR spectra of rabbit bone were dominated by signals of highly mobile triglycerides. These quantitative investigations of natural bone may provide the basis for a quality control of various osteoinductive bone substitutes. We studied the formation of extracellular bone matrix in artificial mesenchymal stem cell-loaded beta-tricalcium phosphate matrices that were implanted into the femoral condyle of rabbits. The NMR spectra of these bone grafts were acquired 3 months after implantation. In the (31)P NMR spectra, beta-tricalcium phosphate and bone calcium phosphate could be distinguished quantitatively, allowing recording of the formation of the natural bone matrix. Further, (13)C CPMAS allowed detection of collagen type I that had been produced in the implants. Comparison with the spectroscopic data from natural bone allowed assessment of the quality of the bone substitute material.

The modular endoprosthetic system Munich-Luebeck (MML) has been in clinical use since 1994. A total of 2.118 pelvic and lower extremity surgeries using the MML system were carried out up until 2010. The modular construction allows substituting or bridging any kind of bone defect. We analyzed 572 operative interventions, which were performed in 5 centers. The most frequent indications were tumors (50.3%) followed by revision arthroplasty due to loosening, periprosthetic fractures, and joint resection surgery due to infection (43.3%). Proximal and distal femoral replacement amounted to 78% of cases, whereas partial pelvic replacement accounted for 10.4% of the cases. Complications were reported in 27.27% of the cases, where dislocations (14.9% of the cases with simultaneous hip replacement) and infections (10.48%) were the most common, as expected. Revision surgery was necessary in 140 (24.8%) of the 572 patients, of which 68 were partial or total replacement of the implants, 16 removal of the implants and 10 above-knee amputations or rather exarticulations of the hip.

Since 1975 the usual treatment of hallux valgus and hallux rigidus at the Medical High School, Lübeck, has been arthrodesis of the metatarophalangeal joint of the great toe. We report 48 operations performed between 1975 and 1977 on 35 patients with a follow-up of 3-32 months. The operative technique, using the "dynamic compression plate" is described in detail. The patient's assessment and the clinical and radiological situations were recorded. There were only three poor results. Thus, arthrodesis of the metatarsophalangeal joint is considered to be a reliable therapeutic method in hallux valgus, with minimal post-operative complications. It compares well with other operations, including Keller's arthroplasty.

Preservation and repair of the hip joint capsule causes an 88-%-reduction of the dislocation rate in primary THA in this large series including 1972 cases, operated via the Bauer or the anterolateral approach. Several authors reported comparable results after THA using similar techniques of soft tissue and capsular repair through the posterior or posterolateral approach. Sparing and reconstructing the hip joint capsule therefore seems to reduce the dislocation rate after primary THA by one order of magnitude regardless of the surgical approach and, especially, if the acetabular origin is preserved. Capsule-related specific complications such as an increased revision rate, malfunction or pain were neither recorded in our study nor by others. Thus, careful preservation and reconstruction of the hip joint capsule may be expressly recommended in primary THA.

The subvastus region and its anatomical contents are important when performing a total knee replacement via a subvastus approach. Thirty-two human cadaver thighs were studied to provide a detailed anatomical description of the subvastus region and its contents, namely the descending genicular artery and its branches, and the saphenous nerve proximally. In 24 specimens the descending genicular artery arose from the femoral artery and divided into osteoarticular and saphenous branches, while in eight specimens it was absent. The osteoarticular and saphenous branches arose independently from the femoral artery. On the basis of these distribution patterns nine variations with regard to the number and origin of the muscular, musculoarticular and saphenomusculoarticular branches arising from these vessels could be identified. The musculoarticular branch should be preserved wherever possible; however, if it must be sacrificed to improve exposure of the knee joint via a proximal extension of the incision, the passage of the saphenous nerve and the saphenous branch through the vastoadductor membrane are additional structures which must be considered. The proximal limitation for the mobilisation is the adductor hiatus, with further mobilisation increasing the risk of damaging the femoral artery and vein.

Our measurements confirm the continual stabilising effect of AP on the hip joint, which can be quantified as the resting potential of stability (RPS) or luxation work (LW). The RPS is calculated by multiplying the difference of AP and saturated vapour pressure of synovial fluid with the cross-sectional area of the femoral head. It represents the force, necessary for luxation of the joint against the resistance of AP. The RPS is proportional to the square of the joint diameter. The LW, calculated by multiplying RPS with the luxation distance, is proportional to the joint diameter cubed. That is why a small increase of joint diameter leads to a significant increase of stability, while the rate of the increase of range-of-motion decreases. To achieve stability of a total hip arthroplasty the size of the joint components should depend on the size of the resected femoral head. Also the hermetically sealed capsule should be reconstructed carefully.

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The onetime epidural lavage presented in this small patient cohort proved to be an effective surgical adjunct with minimal exposure-related morbidity. We believe that the possibility of early mobilization and the patient's increased rehabilitation potential reduce the risk of nosocomial complications that often coincide with this multimorbid high-risk group of patients.