[Knee joint distraction: a solution for young patients with osteoarthritis of the knee?] / Kniedistractie: een oplossing voor jonge patiënten met knieartrose?

The current treatment for patients with end-stage generalised osteoarthritis of the knee is total knee replacement. In a recent paper in Plos One the authors examined an alternative approach, namely knee joint distraction. On the basis of a model, they claim that this treatment can postpone total knee replacement for about 20 years. This would reduce the costs for the healthcare services and improve quality of life for these patients. Although these claims seem promising, the model is only based on extrapolations of short-term results of small cohort studies. Furthermore, concerns about potential complications, e.g. osteomyelitis following pin-tract infections, are not mentioned. Further high quality studies in knee joint distraction are needed to prove its long-term efficacy and safety before this procedure can be implemented in standard clinical care.

[Orthopaedic surgeons can also treat their patients verbally: conservative treatment of osteoarthritis of the knee and hip using careful explanation]. / Orthopeed behandelt ook met woorden.

A recent study of factors that stimulate or hinder conservative treatment of osteoarthritis of the hip or knee concluded that orthopaedic surgeons' beliefs might obstruct application of conservative treatment. Orthopaedic surgeons, along with general practitioners, may play a key role in providing patient-specific conservative treatment. Patients who demand arthroplasty and who are not willing to try conservative treatment may be more problematic. An appreciable percentage of patients are not satisfied after total hip or total knee arthroplasty, so it is of the utmost importance that orthopaedic surgeons provide comprehensive information for all patients, including explaining potential complications and managing expectations. Orthopaedic surgeons should, therefore, treat patients both actively and conservatively.

Electromagnetic fields do not affect bone micro-architecture in osteoporotic rats.

OBJECTIVES: Electromagnetic fields (EMF) are widely used in musculoskeletal disorders. There are indications that EMF might also be effective in the treatment of osteoporosis. To justify clinical follow-up experiments, we examined the effects of EMF on bone micro-architectural changes in osteoporotic and healthy rats. Moreover, we tested the effects of EMF on fracture healing. METHODS: EMF (20 Gauss) was examined in rats (aged 20 weeks), which underwent an ovariectomy (OVX; n = 8) or sham-ovariectomy (sham-OVX; n = 8). As a putative positive control, all rats received bilateral fibular osteotomies to examine the effects on fracture healing. Treatment was applied to one proximal lower leg (three hours a day, five days a week); the lower leg was not treated and served as a control. Bone architectural changes of the proximal tibia and bone formation around the osteotomy were evaluated using in vivo microCT scans at start of treatment and after three and six weeks. RESULTS: In both OVX and sham-OVX groups, EMF did not result in cancellous or cortical bone changes during follow-up. Moreover, EMF did not affect the amount of mineralised callus volume around the fibular osteotomy. CONCLUSIONS: In this study we were unable to reproduce the strong beneficial findings reported by others. This might indicate that EMF treatment is very sensitive to the specific set-up, which would be a serious hindrance for clinical use. No evidence was found that EMF treatment can influence bone mass for the benefit of osteoporotic patients. Cite this article: Bone Joint Res 2014;3:230-5.

Chondrogenically differentiated mesenchymal stromal cell pellets stimulate endochondral bone regeneration in critical-sized bone defects.

Grafting bone defects or atrophic non-unions with mesenchymal stromal cells (MSCs)-based grafts is not yet successful. MSC-based grafts typically use undifferentiated or osteogenically differentiated MSCs and regenerate bone through intramembranous ossification. Endochondral ossification might be more potent but requires chondrogenic differentiation of MSCs. Here, we determined if chondrogenically differentiated MSC (ch-MSC) pellets could induce bone regeneration in an orthotopic environment through endochondral ossification. Undifferentiated MSC pellets (ud-MSC) and ch-MSC pellets were generated from MSCs of human donors cultured on chondrogenic medium for respectively 3 (ud-MSC) and 21 (ch-MSC) days. A 6 mm femoral bone defect was made and stabilised with an internal plate in 27 athymic rats. Defects were left empty for 6 weeks to develop an atrophic non-union before they were grafted with ch-MSC pellets or ud-MSC pellets. Micro-CT scans made 4 and 8 weeks after grafting showed that ch-MSC pellets resulted in significantly more bone than ud-MSC pellets. This regenerated bone could completely bridge the defect, but the amount of bone regeneration was donor-dependent. Histology after 7 and 14 days showed slowly mineralising pellets containing hypertrophic chondrocytes, as well as TRAP-positive and CD34-positive cells around the ch-MSC pellets, indicating osteoclastic resorption and vascularisation typical for endochondral ossification. In conclusion, grafting critical femoral bone defects with chondrogenically differentiated MSC pellets led to rapid and pronounced bone regeneration through endochondral ossification and may therefore be a more successful MSC-based graft to repair large bone defects or atrophic non-unions. But, since bone regeneration was donor-depend, the generation of potent chondrogenically differentiated MSC pellets for each single donor needs to be established first.

Real-time assessment of bone metabolism in small animal models for osteoarthritis using multi pinhole-SPECT/CT.

OBJECTIVE: Destructive techniques such as histology and biochemical assays are still regarded the gold standard to study the effects of novel therapies or etiologic aspects of osteoarthritis in small animal models. These techniques are time-consuming and require many animals. Multi-pinhole single photon emission computed tomography (MPH-SPECT) is a relatively novel, high resolution imaging technique which enables assessment of biological processes in real-time and thus it might provide a good substitute for destructive assessment techniques. DESIGN: For this study, we assessed mono-iodoacetate (MIA) induced osteoarthritic knees in 18 rats. The animals were scanned using MPH-SPECT/CT and a diphosphonate labelled with 99m-technetium as the radioactive tracer to monitor subchondral bone turnover (bone-scan) at 2 (n = 18), 14 (n = 12) and 42 (n = 6) days after injection of MIA. At each time-point six animals were sacrificed and also assessed with high-resolution micro-computed tomography (µCT) and histology. RESULTS: At 2 days after injection of MIA, the MPH-SPECT/CT already showed elevated bone turnover in the affected knee, whereas with histology and µCT we could not detect clear alterations at all this time-point. The increase in bone turnover induced by MIA was elevated further at 14 and 42 days after injection. At this time alterations on histology and µCT scanning also became visible. CONCLUSIONS: MPH-SPECT/CT proved to be a highly sensitive assessment technique for experimental osteoarthritis in small animal models, detecting real-time changes in bone turnover at a very early time point, which might make it a valuable technique to measure the direct effect of interventional strategies on osteoarthritis.

Unfocused extracorporeal shock waves induce anabolic effects in rat bone.

BACKGROUND: Extracorporeal shock waves are known to stimulate the differentiation of mesenchymal stem cells toward osteoprogenitors and induce the expression of osteogenic-related growth hormones. The aim of this study was to investigate if and how extracorporeal shock waves affected new bone formation, bone microarchitecture, and the mechanical properties of bone in a healthy rat model, in order to evaluate whether extracorporeal shock wave therapy might be a potential treatment for osteoporosis. METHODS: Thirteen rats received 1000 electrohydraulically generated unfocused extracorporeal shock waves to the right tibia. The contralateral, left tibia was not treated and served as a control. At two, seven, twenty-one, and forty-nine days after administration of the shock waves, in vivo single-photon-emission computed tomography (SPECT) scanning was performed to measure new bone formation on the basis of uptake of technetium-labeled methylene diphosphonate ((99m)Tc-MDP) (n = 6). Prior to and forty-nine days after the extracorporeal shock wave therapy, micro-computed tomography (micro-CT) scans were made to examine the architectural bone changes. In addition, mechanical testing, microcrack, and histological analyses were performed. RESULTS: Extracorporeal shock waves induced a strong increase in (99m)Tc-MDP uptake in the treated tibia compared with the uptake in the untreated, control tibia. Micro-CT analysis showed that extracorporeal shock waves stimulated increases in both trabecular and cortical volume, which resulted in higher bone stiffness compared with that of the control tibiae. Histological analysis showed intramedullary soft-tissue damage and de novo bone with active osteoblasts and osteoid in the bone marrow of the legs treated with extracorporeal shock waves. Microcrack analysis showed no differences between the treated and control legs. CONCLUSIONS: This study shows that a single treatment with extracorporeal shock waves induces anabolic effects in both cancellous and cortical bone, leading to improved biomechanical properties. Furthermore, treatment with extracorporeal shock waves results in transient damage to the bone marrow, which might be related to the anabolic effects. After further examination and optimization, unfocused extracorporeal shock waves might enable local treatment of skeletal sites susceptible to fracture.