Deep deltoid ligament injury is related to rotational instability of the ankle joint: a biomechanical study.

PURPOSE: In the athletic population, the prevalence of isolated syndesmotic lesions is high. To detect potential instability of the ankle is crucial to define those lesions in need of surgical management. The aim was to define how the extent of tibio-fibular syndesmotic ligament injury influences the overall stability of the ankle joint in a cadaver model. METHODS: Twenty fresh-frozen through knee cadaveric leg specimens were subjected to different simulated syndesmotic ligament lesions. In Group 1 (n = 10), the order of ligament sectioning was: anterior tibio-fibular ligament (ATFL), superficial deltoid ligament (SDL), deep deltoid ligament (DDL), posterior tibio-fibular ligament (PTFL), and progressive sectioning at 10, 50 and 100 mm of the distal interosseous membrane (IOM). In Group 2 (n = 10), the sequence was: ATFL, PITFL, 10 and then 50 mm of the distal IOM, SDL, DDL, and 100 mm of the distal IOM. Diastasis of 4 mm in the coronal or sagittal plane and external rotation of the ankle greater than 20° were considered indicative of instability. RESULTS: Both coronal and sagittal diastasis exceeded 4 mm with injury patterns characterized by IOM lesions extending beyond 5 cm. External rotation of the ankle exceeded 20° with injury patterns characterized by a DDL lesion. CONCLUSION: Coronal and sagittal plane diastases of the tibio-fibular syndesmosis are particularly affected by sequential lesions involving the IOM, whereas increased external rotation of the ankle most depends on DDL. The identification of the specific syndesmotic and deltoid ligament injuries is crucial to understanding which lesions need operative management. The knowledge of which pattern of tibio-fibular syndesmotic ligament injury influences the ankle joint stability is crucial in defining which lesions need for surgical management.

Gene expression, protein profiling, and chemotactic activity of infrapatellar fat pad mesenchymal stem cells in pathologies of the knee joint.

The infrapatellar fat pad (IPFP) is a periarticular adipose knee tissue. This tissue contains a large number of mesenchymal stem cells (MSCs). In the present work, we wanted to study the IPFP MSCs and their relationship and differences in two groups, anterior cruciate ligament (ACL) ruptures knees and ostheoarthrosis (OA). The IPFP of 42 patients with OA or ACL rupture were analyzed. Isolation, primary culture, and a genetic and proteomic study of MSCs from IPFP were performed. Gene expression of IL-6, tumor necrosis factor (TNF), IL-8, HSPA1A (Hsp70), CXCL10, RANTES, MMP1, MMP3, TIMP1, and BMP7 was analyzed by real-time quantitative polymerase chain reaction (RT-qPCR). We analyzed MSCs from from 12 diferents patients in two cellular pools (6 from AO disease and 6 from ALC rupture to form two cell pool), for the iTRAQ Proteomic Assay. The conditional media were used in quantitative analysis of MSC soluble factors by Luminex and for de migration assay. A higher gene expression of IL-6, TNF, CXCL10, RANTES, and MMP1 and OPG in MSCs from OA versus ACL (p < 0.05) was observed. Conversely HSPA1A, TIMP1, and RANKL showed a significant lower expression in OA-MSCs (p < 0.05). In the secretome analysis, adipsin and visfantin levels in the supernatants from OA-MSCs were lower (p < 0.05) respect to ACL-MSCs. Also, the monocytic cells migrated two-folds in the presence of conditioned media from OA-MSCs patients versus patients with ACL-MSC. The infrapatellar pad should be considered as an adipose tissue capable of producing and excreting inflammatory mediators directly in the knee joint, influencing the development and progression of knee joint pathologies.

Does Orientation of the Femoral Head Affect Acetabular Development? An Experimental Study in Lamb.

BACKGROUND: Derotational osteotomy of the proximal femur has proved to be effective in the treatment of residual acetabular dysplasia. However, the reason why this osteotomy is effective remains debatable. The purpose of this study is to investigate if an alteration of femoral head orientation affects acetabular growth. METHODS: A proximal femoral osteotomy was performed in 21 lambs aged 3 months: 5 varus osteotomies (110 degrees), 4 valgus osteotomies (150 degrees), and 12 derotation osteotomies. Results were compared with a control group (5 animals). Osteotomy was fixed with a screw-plate device. Version was controlled intraoperatively with K-wires. Animals were killed 3 months after surgical procedure. A morphometric study of both proximal femur and acetabulum was performed, including deepness, volume and diameters of the acetabulum, neck-shaft angle and femoral version. RESULTS: The average neck-shaft angle for the normal, anteversion, and retroversion groups was 129 degrees, whereas it was 110 degrees for the varus group and 149 degrees for the valgus group. The average femoral version for the normal, valgus, and varus groups was 21 degrees of anteversion, whereas it was 38 degrees of anteversion for the so-called anteversion group and 17 degrees of retroversion for the retroversion group. Nor the neck-shaft angle, nor the femoral version correlated with the acetabular anteroposterior diameter (P=0.698, 0.6, respectively), the acetabular inferosuperior diameter (P=0.083, 0.451, respectively) or the acetabular deepness (P=0.14, 0.371, respectively). The neck-shaft angle correlated significantly with acetabular volume (P=0.023), so that the lower the neck-shaft angle, the higher the acetabular volume (r=-0.453). The femoral version did not correlated with acetabular volume (P=0.381). CONCLUSIONS: Decreasing the neck-shaft angle provokes an increase in acetabular volume, whereas changes in femoral version do not affect the acetabular growth. Extra-articular osteotomies that alter femoral orientation affect intra-articular gross morphology. LEVEL OF EVIDENCE: Level II-therapeutic study.

Long-term results of total knee arthroplasty after failed high tibial osteotomy.

PURPOSE: Sometimes, total knee replacement (TKR) is performed after a tibial osteotomy. It is not known if the osteotomy influences the clinical process of a TKR. The aim of this study was to look at the clinical outcome of a TKR after high tibial osteotomy (HTO) compared to a TKR with no HTO. METHODS: Between 1995 and 2005, 41 post-HTO TKRs (group A) with a minimum follow-up of ten years were selected. In parallel, it was selected a control group undergoing simple TKR, consisting of 41 patients (group B) matched with group A. The Knee Society Knee Score (KS), Knee Score Functional Score (FS), the Oxford Knee Score (OKS), and the range of motion (ROM) were used for evaluation at one, five and ten years after surgery. The Insall-Salvatti ratio (ISR), the posterior tibial slope (PTS), and the joint height line (JHL) were also measured both pre-operatively and post-operatively. RESULTS: No differences were found between both groups in KS, FS, OKS, and ROM at the pre-operative stage or at any of the post-operative controls. Higher patellar height was found in group A, both pre-operatively and post-operatively (p < 0.005), and the same for PTS pre-operative (p < 0.001) and post-operative (p < 0.05). No differences were found regarding the JHL. Post-operative differences were found among the post-HTO subgroups at the FS (p < 0.02), the OKS (p < 0.05), and the ROM (p < 0.01) as a function of whether there was a varus or a valgus deformity before the TKR. CONCLUSION: A HTO was not determinant for having a worse outcome at the TKR, even when there were radiographic differences. The coronal alignment with valgus deformity pre-TKR after a HTO showed better functional results than in the case of varus deformity. Level of evidence III.

Evaluation of lower limb kinetics during gait, sprint and hop tests before and after anterior cruciate ligament reconstruction.

BACKGROUND: The purpose of this study was to evaluate the functional status prior to and at different times after anterior cruciate ligament reconstruction (ACLR), and to analyze the changes in the kinetic patterns of the involved and uninvolved lower limb during gait, sprint and three hop tests. MATERIALS AND METHODS: Seventy-four male patients with an ACL injury were included in the study. All patients performed a standardized kinetic protocol including gait, sprint and three hop tests (single-leg hop, drop vertical jump and vertical jump tests), preoperatively and at 3, 6, and 12 months after ACLR with a semitendinosus gracilis tendon autograft. Measurements were performed with two force plates. The lower limb symmetry index (LSI) was calculated to determine whether a side-to-side leg difference was classified as normal (LSI >90%) or abnormal (LSI <90%). RESULTS: The LSI presented high values (>90%) at almost all times before and after ACLR in gait, sprint and single-leg hop tests (p < 0.005), with a tendency to increase postoperatively. A lower LSI was observed (<90%) in tests where both extremities were tested simultaneously, such as the drop vertical jump and vertical hop tests (p < 0.05). CONCLUSION: We observed a tendency to increase symmetry restoration in the kinetics of the involved and uninvolved limb up to twelve months after ACLR, especially in those tests, in which, both limbs were tested individually (gait analysis, sprint and single-leg hop tests). Therefore, the isolation of the involved and uninvolved limb seems to be a critical component in the functional rehabilitation and evaluation of patients before and after ACLR. LEVEL OF EVIDENCE: level III.

The safe zone for avoiding suprascapular nerve injury in bone block procedures for shoulder instability. A cadaveric study.

PURPOSE: The purpose of the study is to identify the safe zone in which the surgeon can place the screws for fixation of the coracoid graft during the Latarjet procedure to avoid injuries of the suprascapular nerve with the shoulder in internal and external rotation. METHODS: The dissection on twelve fresh-frozen shoulders was performed according to a standard posterior approach to the gleno-humeral joint. The suprascapular nerve and its branches for the infraspinatus muscle were identified at the spinoglenoid notch region. Then, the distance between the glenoid and the suprascapular nerve at the spinoglenoid notch region was measured by using a ruler with the shoulder at 90° internal rotation and at 90° of external rotation. RESULTS: The median distance between the glenoid and the suprascapular nerve was 12 mm (range 6-15 mm) with the shoulder at 90° of internal rotation and 19 mm (range 11-23 mm) with the shoulder at 90° of external rotation. The distance between the glenoid and the suprascapular nerve was statistically significantly greater with the shoulder at 90° of external rotation than 90° of internal rotation (P = 0.002). CONCLUSIONS: The suprascapular nerve is furthest away from the glenoid with the shoulder at 90° of external rotation. Therefore, the placement of screws in external rotation of the humerus during glenoid bone block procedures likely reduces the risk of iatrogenic injuries of the suprascapular nerve.

Evaluation of Elution and Mechanical Properties of High-Dose Antibiotic-Loaded Bone Cement: Comparative "In Vitro" Study of the Influence of Vancomycin and Cefazolin.

Use of antibiotic-loaded bone cements is one of the most effective methods for the prevention and treatment of prosthetic joint infection. However, there is still controversy about the optimal combination and doses of antibiotics that provide the maximum antimicrobial effect without compromising cement properties. In this study, vancomycin and cefazolin were added to a bone cement (Palacos R+G). Antibiotic release, fluid absorption, and mechanical properties were evaluated under physiological conditions. The results show that the type of antibiotic selected has an important impact on cement properties. In this study, groups with cefazolin showed much higher elution than those containing the same concentration of vancomycin. In contrast, groups with cefazolin showed a lower strength than vancomycin groups.

Biomechanical analysis of acromioclavicular joint dislocation repair using coracoclavicular suspension devices in two different configurations.

BACKGROUND: The best treatment option for some acromioclavicular (AC) joint dislocations is controversial. For this reason, the aim of this study was to evaluate the vertical biomechanical behavior of two techniques for the anatomic repair of coracoclavicular (CC) ligaments after an AC injury. MATERIALS AND METHODS: Eighteen human cadaveric shoulders in which repair using a coracoclavicular suspension device was initiated after injury to the acromioclavicular joint were included in the study. Three groups were formed; group I (n = 6): control; group II (n = 6): repair with a double tunnel in the clavicle and in the coracoid (with two CC suspension devices); group III (n = 6): repair in a "V" configuration with two tunnels in the clavicle and one in the coracoid (with one CC suspension device). The biomechanical study was performed with a universal testing machine (Electro Puls 3000, Instron, Boulder, MA, USA), with the clamping jaws set in a vertical position. The force required for acromioclavicular reconstruction system failure was analyzed for each cadaveric piece. RESULTS: Group I reached a maximum force to failure of 635.59 N (mean 444.0 N). The corresponding force was 939.37 N (mean 495.6 N) for group II and 533.11 N (mean 343.9 N) for group III. A comparison of the three groups did not find any significant difference despite the loss of resistance presented by group III. CONCLUSION: Anatomic repair of coracoclavicular ligaments with a double system (double tunnel in the clavicle and in the coracoid) permits vertical translation that is more like that of the acromioclavicular joint. Acromioclavicular repair in a "V" configuration does not seem to be biomechanically sufficient.

Opening wedge high tibial osteotomy: plate position and biomechanics of the medial tibial plateau.

PURPOSE: To ascertain whether changing position and size of the spacer may modify the load and displacement of the tibial plateau when performing an opening wedge high tibial osteotomy. METHODS: Fifteen sawbones tibia models were used. In the axial plane, the anterior, medial, and posterior thirds of the tibial plateau were marked, and the medial and posterior thirds were called "point 1" and "point 2", respectively. A 7.5-mm-stainless steel indenter was used to apply the load over these two points: the load applied to point 1 simulated the load to that site when the knee was extended, and the load to point 2 simulated the load to the same area when the knee was flexed. Maximum load (N) and displacement (mm) were calculated. RESULTS: The system was shown to withstand higher loads with less displacement when the plate was posterior than it could do with the plate in the middle position. Significant differences were also found when comparing the anterior and middle position of the plate with the greatest displacement when the plate was anterior. The differences were increased when comparing the anterior and posterior positions of the plate. No statistical differences (n.s.) were found when using different spacers. The maximum stiffness was achieved if the plate was posterior and in point 1 indenter position, in which the force vector stands on the points of the lateral and medial supports (Fµ = 198.8 ± 61.5 N). The lowest stiffness was observed when the plate was anterior, and the force was applied to point 2 (Fµ = 29.7 ± 5.1 N). CONCLUSIONS: Application of the plate in a more posterior position provides greater stability.

Reliability, validity and responsiveness of the Spanish version of the Knee Injury and Osteoarthritis Outcome Score (KOOS) in patients with chondral lesion of the knee.

PURPOSE: The purpose of this study was to perform a cross-cultural adaptation of the Knee Injury and Osteoarthritis Outcome Score (KOOS) into Spanish and to evaluate the psychometric properties of this version in patients with chondral lesion of the knee, as expressed by its validity, reliability and responsiveness. METHODS: The translation followed an established forward-backward translation procedure with independent translations and counter-translation, according to the recommendations for the cross-cultural adaptation of HRQL measures. Twenty Spanish-speaking patients who underwent arthroscopic surgery for knee cartilage defects with a microfracture technique were enrolled in the study. Diagnosis was made based on clinical criteria and radiological confirmation through magnetic resonance imaging. Patients showing signs of instability, axial malalignment or generalised knee osteoarthritis were excluded from the study. RESULTS: Cronbach's alpha value for the study of the questionnaire was >0.7 in all the KOOS domains except for Symptoms domain. The test-retest reliability was confirmed with an ICC value greater than 0.8 in all the KOOS domains. A significant agreement between the KOOS domains and the scales of the SF-36 with related content, particularly in the areas of physical function and pain, was observed. CONCLUSION: Spanish KOOS questionnaire is valid, reliable and responsive for use in Spanish patients with symptomatic chondral lesion of the knee receiving surgical intervention.

Effects of vancomycin, cefazolin and test conditions on the wear behavior of bone cement.

Antibiotic cement has been recommended in the treatment of prosthetic infections. The purpose of this study was to investigate the mechanical behavioral changes in cement loaded with two antibiotics, vancomycin and cefazolin, in dry and liquid medium. Six groups and four study conditions were established according to the doses of antibiotic used and the ageing (immersion in phosphate buffered saline) of the samples. Properties evaluated were friction coefficient and wear. Samples in dry medium showed higher wears than in liquid. Antibiotic selection did not influence wear properties tested in dry conditions, however, in liquid medium, there were higher frictional coefficients and wear for cefazolin loaded cement after one week and for vancomycin and cefazolin after one month. The results suggest that antibiotic cements behave differently in liquid and that the molecular characteristics of antibiotics are essential for determining this influence.

Analysis of the Initial Learning Curve for Robotic-Assisted Total Knee Arthroplasty Using the ROSA® Knee System.

Background/Objectives: Total knee arthroplasty (TKA) is a frequent procedure in orthopedic surgery. Advances in TKA include the development of robotic-assisted systems. Training in raTKA entails a learning curve to achieve proficiency comparable to conventional manual TKA (maTKA). Methods: We conducted a prospective study of the learning curve in raTKA using the Robotic Surgical Assistant (ROSA) Knee System. The study included 180 patients (90 raTKAs; 90 maTKAs) and three surgeons (one with >15 years of experience in maTKA). The cumulative sum control chart method (CUSUM) was used to define the transition from the learning phase to the mastered phase in raTKA. Results: The learning curves were 43 cases (experienced surgeons) and 61 cases (all surgeons). Mean operative times for both phases in raTKA were longer than in maTKA (p < 0.001). In raTKA, operative times in the learning phase were longer compared to those in the mastered phase (p < 0.001). Operative times in the learning and mastered phases for all surgeons in raTKA were significantly longer compared to those in maTKA (p < 0.001); however, operative times of the experienced surgeon in the mastered phase of raTKA and in maTKA showed no differences. Conclusions: The learning curve in raTKA is dependent upon the surgeon's previous experience in maTKA.

Genome-Wide Association Screens for Anterior Cruciate Ligament Tears.

BACKGROUND: The etiopathogenesis of ACL rupture is not clarified. The aim of this study is to identify genomic regions and genetic variants relevant to anterior cruciate ligament injury susceptibility that could be involved in non-contact anterior cruciate ligament ruptures. METHODS: A systematic review of the literature was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines with a PRISMA checklist and algorithm. A search of PubMed, MEDLINE, CINAHL, Cochrane, EMBASE, and Google Scholar databases was conducted using combinations of the terms "anterior cruciate ligament", "ACL", "rupture", "genetics", "single nucleotide polymorphisms", and "SNP" since the inception of the databases until 2021. RESULTS: Twenty-three studies were included. A total of 7724 patients were analyzed. In total, 3477 patients had ACL ruptures and 4247 patients were controls. Genetic variants in genes encoding for collagens, elastin, fibrillin, matrix metalloproteinases, proteoglycans, angiogenesis-associated signaling cascade proteins, growth differentiation factors, tissue inhibitors of metalloproteases, interleukins, and fibrinogen were analyzed. CONCLUSION: Findings regarding the association between genes encoding for collagen (COL3A1, COL1A1, and COL12A1), aggrecan (ACAN), decorin (DCN), matrix metalloproteinase (MMP3), interleukin 6 (IL-6), vascular endothelial growth factor A (VEGFA), biglycan (BGN), fibrinogen (FGB), and ACL injuries were found to be inconclusive. Additional evidence is required in order to establish substantial conclusions regarding the association between genetic variants and ACL rupture.

Selective epiphysiodesis of the triradiate cartilage for treatment of residual experimental acetabular dysplasia.

BACKGROUND: The purpose of the study is to evaluate the effect of a selective epiphysiodesis of the ilioischial limb of the triradiate cartilage (TC) in an experimental dysplastic hip. MATERIALS AND METHODS: A hip dysplasia was obtained in 23 New Zealand rabbits 3 weeks old by immobilizing the knee in extension with a K-wire, in 4 groups: (1) control group; (2) K-wire maintained until sacrifice; (3) K-wire removed 1 week later without epiphysiodesis; and (4) K-wire removed 1 week later with selective epiphysiodesis of the ilioischial limb of the TC. Radiographic evaluation was performed previous to knee immobilization, after K-wire removal and after sacrifice. Acetabular index (AI), Sharp's angle, ACM angle, acetabular floor thickness ratio (AFTR) were measured and presence of dysplasia, subluxation, or dislocation was noted. The acetabular version, the acetabular sector angles, and the pelvis rotation were obtained using CT evaluation. A morphology score was developed and a morphometric study of both proximal femur and acetabulum was performed. RESULTS: No differences between groups in the radiographic assessment before immobilization or K-wire removal were found. All cases in group 2 showed dysplasia, subluxation, or dislocation of the hip. The radiographic assessment of group 4, compared with group 3, showed a lower AI (P=0.027), Sharp's angle (P=0.005), ACM angle (0.049), and AFTR (P=0.017). No differences between groups 1 and 4 regarding AI (P=0.08), Sharp's angle (P=0.484), and AFTR (P=0.639) were obtained. The morphology score was lower in group 4 than in groups 2 and 3. Group 4 showed a deeper acetabulum than group 2 (P=0.008) and group 3 (P=0.033), while it was similar to group 1 (P=0.364). CONCLUSIONS: A selective epiphysiodesis of the ilioischial limb of the TC in a dysplastic hip normalized the radiographic measurements of the acetabulum and the acetabular deepness, and it improved the previous gross morphology of the capsule, labrum, and ligamentum teres in rabbits. LEVEL OF EVIDENCE: Level II-therapeutic study.

Relationship of the Cruciate and Meniscofemoral Ligaments with the Knee Osteology. An Anatomical Study.

Objective To analyze the dimensions of the posterior cruciate ligament (PCL), anterior cruciate ligament (ACL), the presence of meniscus-femoral ligaments MFLs in human knees, and the correlation with the dimensions of the knee skeleton. Methods Anatomical study on 29 specimens of human knees in which we measured the length and width of the cruciate and meniscus-femoral ligaments and the dimensions of femoral and tibia condyles and the femoral notch. The ACL length was calculated with different degrees of knee flexion. The relationship between the ligaments and bone dimensions were analyzed. Results The length of the ACL and the PCL were similar. Posterior MFL was more frequent and longer than the anterior MFL. We found the posterior MFL in the 72.41% of the knees and anterior MFL in 20.69%. The ACL presented 30% of its maximum length up to 60°, approximately half of its length between 90° and 120°, reaching its maximum length at 170°. We found a strong correlation between the length of the ACL and that of the PCL ( p = 0.001). However, the lengths of the ACL and PCL were not related with the bone dimensions. Conclusion We have found no correlations between the cruciate and MFLs and the anatomical dimensions of the intercondylar notch and the proximal tibia and distal femur. The presence of the posterior MFL was more frequent and longer than that of the anterior ligament.

Safety of International Professional Sports Competitions During the COVID-19 Pandemic: The Association Football Experience.

Major sporting events were suspended during the most acute phase of the COVID-19 pandemic. Competitions are resuming with enhanced hygiene protocols and altered mechanics. While risks for players and staff have been studied, the impact of large-scale tournaments on the communities that host them remains largely unstudied. CONMEBOL Copa América is one of the first wide-scale international tournaments to be conducted in its original format since the beginning of the COVID-19 pandemic. The tournament saw 10 national teams compete in four Brazilian cities during a period of heightened viral transmission. The analysis of over 28,000 compulsory PCR tests showed that positive cases did not lead to the uncontrolled spread of the disease among staff and players. More importantly, the data indicate that locally hired staff were not exposed to increased risk while working. The Copa América experience shows that international sporting competitions can be conducted safely even under unfavourable epidemiological situations.

Variation in Juvenile Long Bone Properties as a Function of Age: Mechanical and Compositional Characterization.

Bone is a heterogeneous, hierarchical biocomposite material made of an organic matrix filled with a mineral component, which plays an important role in bone strength. Although the effect of the mineral/matrix ratio on the mechanical properties of bone during aging has been intensively investigated, the relationship between the mechanical properties and the chemical composition of bone with age requires additional research in juvenile individuals. In this study, bone coupons from bovine and ovine animal species were machined from cortical areas of long bones to quantify whether the variation in mechanical properties at different stages of development is related to the change in the composition of bone tissue. An energy-dispersive X-ray detector (EDX) attached to a scanning electron microscope (SEM) was used to perform a compositional analysis of the tissue. In addition, nanoindentation analyses were carried out to address how the elastic modulus changed with age. Nonparametric statistical analyses found significant differences (p < 0.05) in Ca content and elastic modulus between species, but no differences were found within each species with development. A multiple linear regression model found that the elastic modulus was significantly related to the decrease in P and C in the samples, to the animal species (larger in bovine), and development, although not linearly. This model also found an interaction between Ca and development that could explain the lack of significance of the relationship between the elastic modulus and development in the univariate models.

Early Identification and Treatment of Trochlear Knee Dysplasia.

A shallow sulcus characterizes trochlear dysplasia (TD) of the femoral trochlea, which can lead to chronic pain or instability of the patellofemoral joint. Breech presentation at birth has been identified as a risk factor for developing this condition, which an ultrasound can identify early. Early treatment could be considered at this stage, given the potential for remodelling in these skeletally immature patients. Newborns with breech presentation at birth who meet the inclusion criteria will be enrolled and randomised in equal proportions between treatment with the Pavlik harness and observation. The primary objective is to determine the difference in the means of the sulcus angle between the two treatment arms at two months. Ours is the first study protocol to evaluate an early non-invasive treatment for TD in the newborn with breech presentation at birth using a Pavlik harness. We hypothesised that trochlear dysplasia could be reverted when identified and treated early in life with a simple harness, as it is done with developmental dysplasia of the hip.

Intraosseous injection of mesenchymal stem cells for the treatment of osteonecrosis of the immature femoral head and prevention of head deformity: A study in a pig model.

BACKGROUND: Cell therapy has been proposed as part of the therapeutic arsenal to assist bone formation and remodeling in the early stages of osteonecrosis of the femoral head. The purpose of this study is to determine the effects of intraosseous inoculation of mesenchymal stem cells on bone formation and remodeling in an established experimental model of osteonecrosis of the femoral head in immature pigs. METHODS: Thirty-one 4-week-old immature Yorkshire pigs were used. Experimental osteonecrosis of the femoral head was created in the right hip of all included animals (n = 31). The month after surgery, hip and pelvis radiographs were taken to confirm osteonecrosis of the femoral head. Four animals were excluded following surgery. Two groups were established: (A) mesenchymal stem cell-treated group (n = 13) and (B) saline-treated group (n = 14). One month after surgery the mesenchymal stem cell-group received an intraosseous injection of 10 × 106 mesenchymal stem cell (5 cc) and the saline-treated group of 5 cc of physiological saline solution. Osteonecrosis of the femoral head progression was assessed by monthly X-rays (1-, 2-, 3- and 4-months post-surgery). The animals were sacrificed 1 or 3 months following the intraosseous injection. Repair tissue and osteonecrosis of the femoral head were histologically evaluated immediately after sacrifice. RESULTS: At time of sacrifice, radiographic images showed evident osteonecrosis of the femoral head with associated severe femoral head deformity in 11 of the 14 animals (78%) in the saline group and in only 2 of the 13 animals (15%) in the mesenchymal stem cell group. Histologically, the mesenchymal stem cell group showed less osteonecrosis of the femoral head and less flattening. In the saline group, there was pronounced femoral head flattening and the damaged epiphyseal trabecular bone was largely replaced with fibrovascular tissue. CONCLUSION: Intraosseous mesenchymal stem cells inoculation improved bone healing and remodeling in our immature pig osteonecrosis of the femoral head model. This work supports further investigation to determine whether mesenchymal stem cells enhance the healing process in immature osteonecrosis of the femoral head.

A biomechanical comparison of the primary stability of two minimally invasive techniques for repair of ruptured Achilles tendon.

PURPOSE: To compare the primary stability of two minimally invasive procedures of Achilles tendon (AT) repair, namely a modified percutaneous repair of ruptured AT and the Achillon suture configuration. METHODS: Eighteen (nine matched pairs) frozen ovine ATs were tenotomized 5 cm from the calcaneal insertion. In each pair, one tendon was randomly allocated to one of the two techniques: a modified percutaneous repair group and the Achillon device suture configuration. Specimens were tested performing an unidirectional tensile load to failure using a servo-hydraulic testing device (MTS Systems, Eden Prairie, MN, USA), controlled by an electropulse e3000 INSTRON machine (Instron Ltd, Buckinghamshire, UK). The tendons were then loaded to failure at a rate of 10 mm/s. RESULTS: Two of the nine pairs of specimens were discarded because one specimen for each of the pair pulled out of the pneumatic clamp during mechanical testing. The remaining seven matched pairs were successfully tested. There were no differences in mean strength, mean maximum load, mean failure elongation, tension, stiffness and mode of failure between the two groups. CONCLUSION: The Achillon-like configuration and the modified percutaneous repair of ruptured AT provided similar biomechanical performance.