Comparing Hip Dysplasia in Dogs and Humans: A Review

Hip dysplasia (HD) is common in both humans and dogs. This interconnection is because humans and dogs descended from a common ancestor and therefore have a similar anatomy at micro- and macroscopic levels. Furthermore, dogs are the animals of choice for testing new treatments for human hip dysplasia and orthopedic surgery in general. However, little literature exists comparing HD between the two species. Therefore, the aim of this review is to describe the anatomy, etiology, pathogenesis, diagnostics, and treatment of HD in humans and dogs. HD as an orthopedic condition has many common characteristics in terms of etiology and pathogenesis and most of the differences can be explained by the evolutionary differences between dogs and humans. Likewise, the treatment of HD shows many commonalities between humans and dogs. Conservative treatment and surgical interventions such as femoral osteotomy, pelvic osteotomy and total hip arthroplasty are very similar between humans and dogs. Therefore, future integration of knowledge and experiences for HD between dogs and humans could be beneficial for both species.

The influence of M-CSF on fracture healing in a mouse model

Macrophage colony-stimulating factor 1 (M-CSF) is known to play a critical role during fracture repair e.g. by recruiting stem cells to the fracture site and impacting hard callus formation by stimulating osteoclastogenesis. The aim of this experiment was to study the impact of systemic M-CSF application and its effect on bony healing in a mouse model of femoral osteotomy. Doing so, we studied 61 wild type (wt) mice (18-week-old female C57BL/6) which were divided into three groups: (1) femoral osteotomy, (2) femoral osteotomy + stabilization with external fixator and (3) femoral osteotomy + stabilization with external fixator + systemic M-CSF application. Further, 12 op/op mice underwent femoral osteotomy and served as proof of concept. After being sacrificed at 28 days bony bridging was evaluated ex vivo with µCT, histological and biomechanical testing. Systemic M-CSF application impacted osteoclasts numbers, which were almost as low as found in op/op mice. Regarding callus size, the application of M-CSF in wt mice resulted in significantly larger calluses compared to wt mice without systemic M-CSF treatment. We further observed an anabolic effect of M-CSF application resulting in increased trabecular thickness compared to wt animals without additional M-CSF application. Systemic M-CSF application did not alter biomechanical properties in WT mice. The impact of M-CSF application in a mouse model of femoral osteotomy was oppositional to what we were expecting. While M-CSF application had a distinct anabolic effect on callus size as well as trabecular thickness, this on bottom line did not improve biomechanical properties. We hypothesize that in addition to the well-recognized negative effects of M-CSF on osteoclast numbers this seems to further downstream cause a lack of feedback on osteoblasts. Ultimately, continuous M-CSF application in the absence of co-stimulatory signals (e.g. RANKL) might overstimulate the hematopoietic linage in favor of tissue macrophages instead of osteoclasts.

Femoral Osteotomies for Osteonecrosis of the Femoral Head

Femoral osteotomy is performed for osteonecrosis of the femoral head to prevent the progression of collapse and promote the repair process by transposing the necrotic lesion to the nonweight-bearing portion. The purpose of this review article was to summarize the current knowledge on two types of femoral osteotomy: transtrochanteric anterior or posterior rotational osteotomy and transtrochanteric curved varus osteotomy, both of which are currently performed for osteonecrosis, mainly in Japan and Korea. Osteotomy can be expected to cure osteonecrosis, and no matter how much the durability of artificial joints improves, there will always be young patients for whom the procedure is indicated. We should continue to verify the results of this surgery and refine the techniques involved.

Derotational Femoral Osteotomy for Treating Recurrent Patellar Dislocation in the Presence of Increased Femoral Anteversion: A Systematic Review

Background: Studies on the clinical outcomes of derotational femoral osteotomy to treat recurrent patellar dislocation in the presence of increased femoral anteversion are limited. Purpose: To investigate the role of derotational femoral osteotomy in the treatment of recurrent patellar dislocation in the presence of increased femoral anteversion. Study Design: Systematic review; Level of evidence, 4. Methods: A systematic review was performed according to the PRISMA guidelines (Preferred Reporting Items for Systematic Reviews and Meta-analyses) by searching the Medline, Embase, Web of Science, and Cochrane Library databases through February 10, 2021. Included were studies of skeletally mature patients presenting with recurrent patellar dislocation and exhibiting increased femoral anteversion who subsequently underwent derotational femoral osteotomy. Methodological quality was assessed using the MINORS (Methodological Index for Nonrandomized Studies) score. The basic characteristics of each study were recorded and analyzed: characteristic information, radiological parameters, surgical techniques, patient-reported outcomes, and complications. Results: A total of 6 studies with 163 patients (170 knees) were included. Sample sizes ranged from 7 to 66 patients, and the patients were predominantly women (range, 79%-100%). The mean age and follow-up ranges were 18 to 28 years and 16 to 44 months, respectively. The mean femoral anteversion decreased significantly from 34° preoperatively to 12° postoperatively. In studies reporting pre- and postoperative outcomes, significant improvements were found in the Lysholm score (from 24.8 to 44.1), Kujala score (from 15.8 to 41.9), International Knee Documentation Committee score (from 11.0 to 28.0), and visual analog scale for pain (from 2.0 to 3.7). All studies reported postoperative complications, giving an overall reported complication rate of 4.7%, but no redislocations occurred during the follow-up period. Conclusion: For recurrent patellar dislocation in the presence of increased femoral anteversion, combination treatment with derotational femoral osteotomy led to favorable clinical outcomes with a low redislocation rate. However, there was no consensus among researchers on the indications for derotational femoral osteotomy in the treatment of recurrent patellar dislocation.