The Prevalence of Chronic Interosseous Membrane Lesions Following Mason II and III Radial Head Fractures in Complex Elbow Instability-A Retrospective Observational Cohort Study.

PURPOSE: The primary aim of the present study was to assess the prevalence of chronic lesions of the central band of the interosseous membrane (cbIOM) in complex elbow instability (CEI) in a consecutive series of patients who had previously undergone surgical treatment for Mason II and III radial head (RH) fractures. The secondary aim was to define its clinical significance. METHODS: We performed a retrospective study on a prospective database. Our study population comprised 93 patients affected by CEI with type II or III RH fractures according to Mason's classification who were analyzed in the chronic setting. All patients were treated according to the current therapeutic algorithms. At the last follow-up, the "muscular hernia sign" was investigated by means of a bilateral ultrasonographic examination to assess any chronic cbIOM lesions; the Mayo Elbow Performance Score (MEPS) was used to evaluate the clinical significance of these lesions. RESULTS: All 93 patients were assessed after a mean time of 7.3 years (range: 2-12). No positive "hernia signs" were found, while five patients (5.4%) displayed an increased laxity of the cbIOM when compared with the contralateral side despite a negative "hernia sign". The clinical outcome in all five patients was excellent with a mean MEPS of 96 (range, 90-100). CONCLUSIONS: Chronic cbIOM lesions are very rare in CEI with RH fractures. No patients in this large sample displayed a cbIOM complete lesion; in cases with increased laxity, satisfactory mid-term clinical results were observed. Considering that previous studies reported (1) a high prevalence of cbIOM lesions in patients with Mason II and III RH fractures and (2) the current expert opinion about the scarce healing potential of the cbIOM, this study also suggests that the IOM may heal better than previously believed when RH fractures are treated appropriately in the acute setting.

Multiple fractures of the femur: Case report, literature review, and proposal for a shared algorithm of treatment.

Multiple fractures of the femur, defined for the purposes of this study as the association of three or more non-contiguous fractures on the same bone segment, is an exceedingly rare condition with an unknown incidence in the literature. A limited number of studies, mainly consisting of case reports or small case series, have addressed this topic, and no shared consensus or guidelines exist on what the ideal timing and sequence of multiple fracture fixation is. The present paper reports the clinical case of a 36 years old man who sustained a blunt chest injury, a non-concussive head injury, a displaced intracapsular fracture of the left femur (AO 31B2), a left diaphyseal multifragmentary fracture (AO 32B3), a supradiacondylar fracture of the distal end of the left femur (AO 33C1.1), a Hoffa fracture of the lateral left femoral condyle (AO 33B3.2 f), and a multifragmentary fracture of the left patella with bone loss (AO 34C3) due to a vehicular high-energy trauma. The patient was surgically treated by open reduction and internal fixation according to a proposed algorithm of treatment and reported excellent clinical and radiological outcomes at 32 months follow-up. The primary aim of this study is to describe our experience in the treatment of such complex fractures, by presenting our clinical and radiological results, and to propose a treatment algorithm. The secondary aim is to provide a comprehensive review of the literature on this topic.

Stress Shielding around Press-Fit Radial Head Arthroplasty: Proposal for a New Classification System Based on the Analysis of 97 Patients with a Mid-Term Follow-Up and a Review of the Literature.

Stress shielding (SS) around press-fit radial head arthroplasty (RHA) was recently reported as a cause of a new type of proximal radial neck resorption (PRNR). Very few studies have analyzed this phenomenon. No comprehensive classification is currently available. We thus decided to clinically and radiographically analyze 97 patients who underwent a press-fit RHA and who were followed up for a mean period of 72 months (range: 2-14 years). PRNR in the four quadrants of the radial neck was assessed. We designed a novel SS classification based on (1) the degree of resorption of the length of the radial neck and (2) the number of neck quadrants involved on the axial plane. The mean PRNR (mPRNR) was calculated as the mean resorption in the four quadrants. mPRNR was classified as mild (<3 mm), moderate (3 to 6 mm), and severe (>6 mm). Eighty-four percent of the patients presented PRNR. mPRNR was mild in 33% of the patients, moderate in 54%, and severe in 13%. In total, 6% of the patients with mild mPRNR displayed resorption in one quadrant, 18% displayed resorption in two quadrants, 4% displayed resorption in three quadrants, and 72% displayed resorption in four quadrants. All four quadrants were always involved in moderate or severe mPRNR, with no significant differences being detected between quadrants (p = 0.568). mPRNR has no apparent effect on the clinical results, complications, or RHA survival in the medium term. However, longer-term studies are needed to determine the effects of varying degrees of PRNR on implant failure.

A pathogenic role for brain-derived neurotrophic factor (BDNF) in fibrous dysplasia of bone.

Brain derived neurotrophic factor (BDNF) is a neurotrophin, expressed in the central nervous system and in peripheral tissues, that is regulated by the Gsα/cAMP pathway. In bone, it regulates osteogenesis and stimulates RANKL secretion and osteoclast formation in osteolytic tumors such as Multiple Myeloma. Fibrous dysplasia (FD) of bone is a rare genetic disease of the skeleton caused by gain-of-function mutations of the Gsα gene in which RANKL-dependent enhanced bone resorption is a major cause of bone fragility and clinical morbidity. We observed that BDNF transcripts are expressed in human FD lesions. Specifically, immunolocalization studies performed on biopsies obtained from FD patients revealed the expression of BDNF in osteoblasts and, to a lower extent, in the spindle-shaped cells within the fibrous tissue. Therefore, we hypothesized that BDNF can play a role in the pathogenesis of FD by stimulating RANKL secretion and bone resorption. To test this hypothesis, we used the EF1α-GsαR201C mouse model of the human disease (FD mice). Western blot analysis revealed a higher expression of BDNF in bone segments of FD mice compared to WT mice and the immunolabeling pattern within mouse FD lesions was similar to that observed in human FD. Treatment of FD mice with a monoclonal antibody against BDNF reduced the fibrous tissue along with the number of osteoclasts and osteoblasts within femoral lesions. These results reveal BDNF as a new player in the pathogenesis of FD and a potential molecular mechanism by which osteoclastogenesis may be nourished within FD bone lesions. They also suggest that BDNF inhibition may be a new approach to reduce abnormal bone remodeling in FD.

Higher rates of fully preserved posterior cruciate ligament in total knee arthroplasty using a double tibial cut: a prospective randomized controlled trial.

PURPOSE: In cruciate retaining total knee arthroplasty, posterior cruciate ligament damage may occur during tibial cutting. A prospective randomized study was conducted to investigate whether a novel tibial cutting technique was more effective than the currently used techniques. MATERIALS AND METHODS: Patients undergoing cruciate retaining total knee arthroplasty were recruited in a prospective, randomized, controlled trial. In 25 patients (group 1) the tibial cut was performed using a double tibial cut technique; in 25 (group 2) and 25 (group 3) patients, the bone island and en bloc resection techniques were performed, respectively. Posterior cruciate ligament integrity and femoral rollback were assessed at the end of surgery. The Oxford Knee Score, WOMAC score and range of motion were assessed postoperatively. RESULTS: Posterior cruciate ligament was completely preserved in 92% of patients in group 1 and in 64% in group 2 and 3, respectively (p = 0.03). The Oxford Knee Score and WOMAC scores did not differ between groups (p = 0.4). The mean knee flexion was 126.4°, 121.5° and 123.9° in groups 1, 2 and 3, respectively (p = 0.04). The femoral rollback at 120° flexion was 80.7%, 72.2% and 75.4% in groups 1, 2 and 3, respectively (p = 0.01). CONCLUSIONS: The double cut technique preserves the posterior cruciate ligament at significantly higher rates than the bone island or en bloc resection techniques. Better posterior cruciate ligament preservation may improve the femoral rollback and knee flexion. LEVEL OF EVIDENCE: Prospective randomized controlled trial, Level I.

Assessment of progression and clinical relevance of stress-shielding around press-fit radial head arthroplasty.

Aims: The aim of this study was to analyze how proximal radial neck resorption (PRNR) starts and progresses radiologically in two types of press-fit radial head arthroplasties (RHAs), and to investigate its clinical relevance. Methods: A total of 97 patients with RHA were analyzed: 56 received a bipolar RHA (Group 1) while 41 received an anatomical implant (Group 2). Radiographs were performed postoperatively and after three, six, nine, and 12 weeks, six, nine, 12, 18, and 24 months, and annually thereafter. PRNR was measured in all radiographs in the four radial neck quadrants. The Mayo Elbow Performance Score (MEPS), the abbreviated version of the Disabilities of the Arm, Shoulder, and Hand questionnaire (QuickDASH), and the patient-assessed American Shoulder and Elbow Surgeons score - Elbow (pASES-E) were used for the clinical assessment. Radiological signs of implant loosening were investigated. Results: The mean follow-up was six years (2 to 14). PRNR started after a mean of 7.5 weeks (SD 2.1) and progressed significantly during the first two years, by the end of which the bone resorption stabilized. PRNR was detected in 81% (n = 45) of patients in Group 1 and 88% (n = 36) in Group 2. The final mean PRNR was 3.0 mm (SD 2.3) in Group 1 and 3.7 mm (SD 2.5) in Group 2. The mean MEPS, QuickDASH, and pASES-E were 95.9 (SD 11.5), 4.4 (SD 9.2), and 94.8 (SD 10.9) in Group 1 and 92.2 (SD 16.2), 9.9 (SD 21.5), and 90.8 (SD 15) in Group 2, respectively. No significant differences were observed between groups in the clinical and radiological outcomes. No correlations were found between PRNR and the clinical results. Conclusion: PRNR after press-fit RHA is a common radiological finding that develops in the first 24 months before stabilizing definitively. PRNR does not affect the clinical results or implant survival in the mid term.

The iliac stemmed cup in reconstruction of the acetabular defects secondary to tumor resection: a systematic review of literature.

INTRODUCTION: Stemmed acetabular cups are suitable for reconstruction in case of important bone loss. Nevertheless, their use is not so common, because generally judged very invasive and technically difficult to implant. The aim of the present review is to verify the results of their use and to evaluate indications and complications. MATERIALS AND METHODS: Literature research was performed in the main healthcare databases; indications, surgical technique, related complications, functional results and implant survival were valued and analyzed for every selected paper. RESULTS: 13 studies were selected, for a population of 424 patients and 428 hips. The main indication was reconstruction after tumor removal; the primary non-oncologic indication was revision for aseptic loosening. The most frequent complications were aseptic loosening and implant failure (16.2%), followed by deep infection (11.3%) and dislocation (9.8%). The average MSTS score was 65.9%; while data regarding functional results for degenerative cases are quite fragmented. The 5-years implant survival was 73.6%. CONCLUSIONS: Data regarding SAC prostheses are quite rare in the literature; no prospective studies with comparisons with other reconstruction techniques are available so their use is mainly based on the experience of single centers. While data for tumors are more consistent and supported by studies, information on revisions of hip prosthesis implanted for degenerative problems is quite scarce. Preliminary results on the SAC prosthesis as a valid alternative both for tumoral and degenerative revision cases are encouraging. Prospective randomized studies are advocated to value results compared to alternative techniques.

Morphometric analysis of the lateral column of the distal humerus with an interest on radio-capitellar arthroplasty design. A computed tomography anatomical study on 50 elbows.

PURPOSE: To perform a morphometric analysis of the distal humerus lateral column medullary canal (LCMC). METHODS: Fifty computed tomography(CTs) from 24 males and 26 females were examined. Two observers measured: (1) the capitellum sagittal (RS) and axial (RT) radii of curvature; (2) the sagittal(Sd) and coronal(Cd) diameters of the LCMC in 5 different disto-proximal sites spaced 4 mm apart; (3) the capitellum and LCMC axis offsets on the sagittal (capSO,axSO) and coronal (capCO,axCO) planes; (4) the sagittal (Si) and coronal (Ci) inclination of the LCMC axis. RESULTS: The mean RS and RT were 1.07 cm (SD, 0.11) and 1.30 cm (SD, 0.11), respectively. The mean Sd and Cd values were 1.17 cm (SD, 0.17) and 1.58 cm (SD, 0.24), respectively, with a disto-proximal decrease on both planes. The capSO, capCO, axSO and axCO mean values were 0.76 (SD, 0.21), 1.60 (SD, 0.27), - 0.16 (SD, 0.30) and 0.79 cm (SD, 0.30), respectively. Si and Ci were 70° and 72°, respectively. A strong correlation (r = 0.78) was found between RS and RT and between adjacent levels of Sd and Cd. AxSO and axCO yielded a strong inverse correlation. Male patients showed higher values than female ones in all variables (p < 0.03). The intra-class correlation coefficient (ICC) was always > 0.9. CONCLUSION: The dimensions of the LCMC decrease disto-proximally, with the coronal diameters being greater than the sagittal diameters, resembling a portion of an elliptic torus with an antero-medial concavity. The articular surface of the humeral capitellum is non-spherical, with two strongly correlated radii of curvature. The results of this study may be relevant to the stem design of radiocapitellar arthroplasty.

Epidemiology of isolated olecranon fractures: a detailed survey on a large sample of patients in a suburban area.

BACKGROUND: Literature lacks data concerning several epidemiologic aspects of isolated olecranon fractures (IOFs). The few studies that have analyzed this type of fracture show a low sample size and contradicting results. METHODS: This retrospective study included 165 consecutive patients (82 men and 83 women) who sustained an IOF in the past 10 years. Participants who were aged <16 years or had a previous elbow fracture or had a fracture that involved other bones of the elbow joint were excluded. Data regarding age, sex, season, date, and fracture side were collected. As per the mechanism of injury, we arbitrarily distinguished 7 subgroups. IOFs were classified as per the Mayo and AO classifications using x-ray. Statistics were performed. RESULTS: The patients' mean age was 58.5 (standard deviation [SD], 21.3) years, and men and women were aged 48.1 (SD, 19.8) years and 67.9 (SD, 18.8) years, respectively. The most frequent fracture patterns were the MAYO 2A and the AO 2U1B1(d). Low-energy mechanisms caused simple dislocated-stable fractures, whereas high-energy mechanisms caused both simple and comminuted displaced-stable fractures. Significant differences in the trauma mechanism were found between male and female patients. The former fractures showed a bimodal distribution depending on the patients' age group, whereas in women, the traumatic event was mainly represented by a low-energy mechanism. Overall, the most common cause of fracture was a low-energy accident. The seasonal distribution of fractures was different for male and female patients being more frequent in summer among young men and more frequent in winter among the elderly, both men and women. The left side was involved in 87 patients. CONCLUSION: IOFs occur equally in both genders, although with different age distribution. The most common fracture pattern was a simple displaced-stable fracture (MAYO 2A and AO 2U1B1[d]). Young men are more often subject to high-energy injuries that occur in road accidents, whereas with aging, they become more prone to fragility fractures as women. Female patients are usually older and are mostly affected by low-energy traumas as a fall from a standing height.

Primary complex total knee arthroplasty with severe varus deformity and large bone defects: mid-term results of a consecutive series treated with primary implants.

INTRODUCTION: In recent years, the use of constrained implants in complex primary TKA has gained popularity since these implants may better and more easily address severe instability present in complex primary cases (CPC). However, the need for a constrained TKA in CPC is controversial. We hypothesized that a standard TKA may be successful in most of CPC and that an intraoperative switching to a constrained device is rarely need even in the presence of severe instability and bone loss. MATERIALS AND METHODS: A consecutive series of 24 CPC (28 knees) were analysed retrospectively. Inclusion criteria were a femoro-tibial angle > 12° and bone defect of grade 2-3 (group 1). Forty-eight patients (52 knees) were analysed as controls (group 2). Patients were followed up clinically and radiographically up to a minimum of 5 years. RESULTS: In group 1, a PS was used in 24 knees and a CR in 4. In no patient, a CCK or RHK was implanted. Bone defect was treated with bone cement plus cortical screws in 15 knees (53.5%), a medial wedge in 8 (28.5%), a medial wedge plus bone grafting with cancellous screws in 5 (17.8%). Metaphyseal sleeve or cone was not used. At the last follow-up, no significant difference was found in the clinical scores between the 2 groups. CONCLUSION: In CPC with marked varus deformity, instability and bone loss, the use of primary TKA is associated with a clinical outcome comparable to standard cases. Ligamentous balancing may be addressed using primary implants and simple cost-effective techniques may be used to manage an extensive bone loss. In most CPC, an intraoperative switching to a constrained device is not necessary.

Does shape and size of the stems affect the stress-shielding around press-fit radial head arthroplasty?

AIMS: It has been hypothesized that proximal radial neck resorption (PRNR) following press-fit radial head arthroplasty (RHA) is due to stress-shielding. We compared two different press-fit stems by means of radiographs to investigate whether the shape and size of the stems are correlated with the degree of PRNR. METHODS: The radiographs of 52 RHAs were analyzed both at 14 days postoperatively and after two years. A cylindrical stem and a conical stem were implanted in 22 patients (group 1) and 30 patients (group 2), respectively. The PRNR was measured in the four quadrants of the radial neck and the degree of stem filling was calculated by analyzing the ratio between the prosthetic stem diameter (PSD) and the medullary canal diameter (MCD) at the proximal portion of the stem (level A), halfway along the stem length (level B), and distally at the stem tip (level C). RESULTS: Overall, 50 of the 52 patients displayed PRNR. The mean PRNR observed was 3.9 mm (0 to 7.4). The degree of endomedullary stem filling at levels A, B, and C was 96%, 90%, and 68% in group 1, and 96%, 72%, and 57%, in group 2, with differences being significant at levels B (p < 0.001) and C (p < 0.001). No significant correlations emerged between the severity of PRNR and the three stem/canal ratios either within each group or between the groups. CONCLUSION: PRNR in press-fit RHA appears to be independent of the shape and size of the stems. Other causes besides stem design should be investigated to explain completely this phenomenon. Cite this article: Bone Joint J 2021;103-B(3):530-535.

Correlations Between Radial Head Diameters and Humeral Articular Dimensions: Bilateral MRI Morphometric Analysis on 39 Healthy Subjects.

PURPOSE: Choosing the correct size of head component in radial head arthroplasty is often challenging, particularly in comminuted fractures, deformities, and revision surgery. The main aim of this study was to investigate possible correlations between radial head diameters and the morphometric parameters of the articular distal humerus in order to find mathematical equations that may be used to infer radial head dimensions indirectly. METHODS: We performed bilateral elbow magnetic resonance imaging on 39 healthy young subjects, comprising 19 women and 20 men, with a mean age of 28 years (range, 21-32 years). The following measurements, which included cartilage thickness, were calculated on the axial plane: maximum (Dmax) and minimum (Dmin) radial head diameters, capitellum width, capitellum to lateral trochlear ridge width (CAP-TROCHridge), humeral articular width (HUMwidth), capitellum radius of curvature, and lateral, medial, and total trochlear width. The anteroposterior diameters of the capitellum, trochlear sulci, and lateral and medial trochlear ridges were measured on the sagittal plane. RESULTS: CAP-TROCHridge and HUMwidth were found to be the parameters most strongly correlated with the radial head diameters. Four mathematical equations that allowed Dmax and Dmin to be calculated with an average residual error less than 1 mm, were obtained. The intraclass coefficient was greater than 0.95 for all the measurements. CONCLUSIONS: Radial head diameters can be accurately inferred from 2 humeral dimensions by magnetic resonance imaging. The HUMwidth, which is not influenced by cartilage thickness, may be useful for planning with preoperative imaging because it can also be calculated by computed tomography scan, whereas CAP-TROCHridge, which is influenced by cartilage thickness, might be useful for direct intraoperative measurement. TYPE OF STUDY/LEVEL OF EVIDENCE: Diagnostic III.

Plain films are not accurate in planning internal fixation in vancouver type B1 periprosthetic femoral fractures and in distinguishing between subtypes B1 And B2.

BACKGROUND: While few studies analysed the diagnostic validity of preoperative radiographs in distinguishing between Vancouver type B1 and B2 periprosthetic femoral fractures (PFFs), no investigation has been conducted to assess the degree of diagnostic validity of preoperative radiographs in identifying the fracture course and planning the most appropriate treatment. We analysed the diagnostic validity of radiographs in detecting the fracture course and stem stability in Vancouver type B PFFs. METHODS: Vancouver type B PFFs with different fracture courses were randomly performed in 36 dried cadaveric femurs in which a femoral broach had previously been implanted. Radiographic images, taken in the coronal and sagittal views, were analysed by 5 orthopaedic surgeons and 2 radiologists who were asked to reproduce the fracture course and to evaluate stem stability. A scoring system was used to determine the injured femoral cortex correctly identified by the examiners. RESULTS: The identification of the fracture course was scored as poor in 52.4% and 56.%, fair in 23% and 23.4% and good in 24.6% and 19.8%, The identification of the fracture course in the coronal and axial vies radiographs was scored in coronal and axial view radiographs respectively. There was no significant difference in the average score obtained by senior and young examiners. In the coronal plane, the fracture course was poorly identified by all examiners in 11 (30.5%) femurs and by 5 or more examiners in 17 (47%). The fracture course was correctly identified by 5 or more examiners in 8 femurs (22%). A vertical fracture involving an emidiaphysis was found in 8 of the 11 femurs in which the PFF was poorly diagnosed by all examiners. Stem instability was correctly diagnosed in 45% of cases. CONCLUSIONS: In type B PFFs preoperative radiographs show a reduced diagnostic validity in identifying the fracture course and, hence, in planning a correct treatment. Potentially unstable vertical fractures involving an emidiaphysis are likely to be poorly diagnosed since most of the fracture course is hidden by the femoral stem. In cementless stems the diagnostic validity of radiographs in diagnosing between Vancouver type B1 and B2 seems to be lower than that reported for cemented stems.

Revisiting the tibial crest as reference for the mechanical alignment of the tibial component in total knee arthroplasty: a cadaveric study on Caucasian tibiae.

PURPOSE: The accuracy of the tibial crest (TC) in guiding the mechanical alignment of the tibial component in total knee arthroplasty (TKA) has been investigated in a few studies on Asian patients. No study analyzed the anatomical variants of the TC. We analyzed the morphological types of the TC in cadaveric tibiae of Caucasian subjects and assessed whether the TC may be considered an accurate guide for the mechanical alignment of the tibial component in TKA. METHODS: The TC and mechanical axis (MA) were identified in 86 dried cadaveric tibiae by placing metal landmarks along the TC course and a guidewire overlapping the MA. Coronal view radiographs were taken in different positions of tibial axial rotation, and the relationships between the TC and MA were analyzed. RESULTS: The TC showed three different patterns, comprising a curved, mixed and straight course in 47 (54.6%), 21 (24.4%) and 18 (20.9%) tibiae, respectively. When a curved course was found, the TC intersected the MA at proximal and distal points located, on average 22.4% and 63.3% along the tibial length, respectively. When a straight course was found, the mean angle between the TC and MA was 2.9°. In 35% of the cases, the two axes differed by more than 3°. CONCLUSION: The TC of Caucasian subjects exhibits a marked variability in its course and relationship with the MA. Unlike the TC in Asian subjects, the TC of Caucasians cannot be considered an accurate anatomical reference to guide the coronal alignment of the tibial component in TKA.

Chronic complex persistent elbow instability: a consecutive and prospective case series and review of recent literature.

BACKGROUND: Chronic complex persistent elbow instability (CCPEI) is a condition that even expert elbow surgeons find challenging to treat. The results of the few studies that have dealt with the treatment of this condition are conflicting. We describe the surgical results of a consecutive prospective series of patients with CCPEI and provide a review of the recent literature. METHODS: We assessed 21 patients with previous failed surgical or conservative treatment, with a terrible-triad injury in 13, Monteggia-like lesion in 6, humeral shear fracture-dislocation in 1, and radial head fracture-dislocation in 1. Overall, 21 open débridement procedures, 15 ulnar nerve transpositions, 6 ulnar in situ neurolysis procedures, 7 total elbow arthroplasties, 8 radial head arthroplasties, 1 radial head resection with humeroradial anconeus interpositional arthroplasty, 4 coronoid graft reconstructions, 14 ligament retensioning procedures, 3 ulnar nonunion treatments, and 2 ulnar osteotomies were performed. Two dynamic external fixators were applied. The Mayo Elbow Performance Score, quick Disabilities of the Arm, Shoulder and Hand score, and modified American Shoulder and Elbow Surgeons score were used preoperatively and postoperatively. RESULTS: The mean follow-up period was 29.4 months. A significant improvement was found between preoperative and postoperative clinical scores and range-of-motion values. The reintervention and major complication rates were 19% and 23%, respectively. Arthritic evolution was observed in 71% of the cases. CONCLUSIONS: CCPEI is a challenging condition with an uncertain prognosis. The variability in patients' pathoanatomic conditions requires customized surgical treatment aimed at elbow stabilizer reconstruction when the ulnohumeral joint is preserved or aimed at joint replacement in case of severe articular degeneration. The time interval between the initial trauma and index surgical procedure significantly affects the feasibility of reconstructive procedures.

Changes in gene expression in human skeletal stem cells transduced with constitutively active Gsα correlates with hallmark histopathological changes seen in fibrous dysplastic bone.

Fibrous dysplasia (FD) of bone is a complex disease of the skeleton caused by dominant activating mutations of the GNAS locus encoding for the α subunit of the G protein-coupled receptor complex (Gsα). The mutation involves a substitution of arginine at position 201 by histidine or cysteine (GsαR201H or R201C), which leads to overproduction of cAMP. Several signaling pathways are implicated downstream of excess cAMP in the manifestation of disease. However, the pathogenesis of FD remains largely unknown. The overall FD phenotype can be attributed to alterations of skeletal stem/progenitor cells which normally develop into osteogenic or adipogenic cells (in cis), and are also known to provide support to angiogenesis, hematopoiesis, and osteoclastogenesis (in trans). In order to dissect the molecular pathways rooted in skeletal stem/progenitor cells by FD mutations, we engineered human skeletal stem/progenitor cells with the GsαR201C mutation and performed transcriptomic analysis. Our data suggest that this FD mutation profoundly alters the properties of skeletal stem/progenitor cells by pushing them towards formation of disorganized bone with a concomitant alteration of adipogenic differentiation. In addition, the mutation creates an altered in trans environment that induces neovascularization, cytokine/chemokine changes and osteoclastogenesis. In silico comparison of our data with the signature of FD craniofacial samples highlighted common traits, such as the upregulation of ADAM (A Disintegrin and Metalloprotease) proteins and other matrix-related factors, and of PDE7B (Phosphodiesterase 7B), which can be considered as a buffering process, activated to compensate for excess cAMP. We also observed high levels of CEBPs (CCAAT-Enhancer Binding Proteins) in both data sets, factors related to browning of white fat. This is the first analysis of the reaction of human skeletal stem/progenitor cells to the introduction of the FD mutation and we believe it provides a useful background for further studies on the molecular basis of the disease and for the identification of novel potential therapeutic targets.

Post-traumatic proximal radioulnar synostosis: results of surgical treatment and review of the literature.

BACKGROUND: Post-traumatic proximal radioulnar synostosis is a very rare and disabling condition whose surgical treatment has traditionally been viewed with pessimism. The results of the few case series in the literature are conflicting. Our aims were (1) to describe the clinical results of a case series treated surgically by a single elbow surgeon and (2) to review the literature. METHODS: Twelve patients were evaluated. Preoperative radiographs and computed tomography scans were performed. According to the Viola and Hastings classification, there was 1 case of type IC synostosis; 3, type IIA; 2, type IIIA; and 8, type IIIB. Two patients had a double synostosis. The synostosis was excised in 10 cases; in addition, radial head excision, radial head arthroplasty, and proximal radial diaphyseal resection were performed in 1, 3, and 2 cases, respectively. The Mayo Elbow Performance Score, modified American Shoulder and Elbow Surgeons score, and QuickDASH (short version of Disabilities of the Arm, Shoulder and Hand questionnaire) score were used for the preoperative and postoperative evaluation. The nonparametric Wilcoxon signed rank test was used for the statistical analysis. RESULTS: The mean follow-up period was 20.5 months. The final mean extension-flexion and pronation-supination arcs were 116° and 123°, respectively. Significant improvements were found in the Mayo Elbow Performance Score (P = .005), modified American Shoulder and Elbow Surgeons score (P = .012), and QuickDASH score (P = .002), with mean values of 24, 28, and 17, respectively. One synostosis recurrence and one late disassembly of the radial head arthroplasty were observed. CONCLUSIONS: Post-traumatic proximal radioulnar synostosis surgery is effective, but careful preoperative planning based on the pathoanatomic characteristics of each type of synostosis and associated lesions is mandatory. Synostosis excision is performed in most cases, whereas additional surgical procedures should be considered in selected cases.

Midterm results of radiocapitellar arthroplasty of the elbow: a multicentre prospective study on two different implants.

AIMS: The aim of this study was to analyze the results of two radiocapitellar prostheses in a large case series followed prospectively, with medium-term follow-up. PATIENTS AND METHODS: A total of 31 patients with a mean age of 54 years (27 to 73) were analyzed; nine had primary osteoarthritis (OA) and 17 had post-traumatic OA, three had capitellar osteonecrosis, and two had a fracture. Overall, 17 Lateral Resurfacing Elbow (LRE) and 14 Uni-Elbow Radio-Capitellum Implant (UNI-E) arthroplasties were performed. Pre- and postoperative assessment involved the Mayo Elbow Performance Score (MEPS), the Quick Disabilities of the Arm, Shoulder and Hand (Q-DASH) score, and the modified American Shoulder Elbow Surgeons (m-ASES) score. RESULTS: The mean follow-up was 6.8 years (3.8 to 11.5). The mean MEPS, m-ASES, and Q-DASH scores improved significantly by 50 (p < 0.001), 55 (p < 0.001), and 54 points (p < 0.001), respectively, with no differences being detected between the implants. Preoperative pronation and supination were worse in patients in whom the UNI-E was used. Two patients with the UNI-E implant had asymptomatic evidence of gross loosening. CONCLUSION: Radiocapitellar arthroplasty yielded a significant improvement in elbow function at a mean follow-up of 6.8 years, with a high implant survival rate when the LRE was used in patients with primary or post-traumatic OA, without radial head deformity, and when the UNI-E was used in patients in whom radial head excision was indicated. Cite this article: Bone Joint J 2019;101-B:1362-1369.

The attempt of spontaneous repair of rotator cuff tear: The role of periostin.

The development of a periostin-rich microenvironment in areas associated with insult, orchestrating pathways of repair and rebuilding, is documented. Literature lacks information regarding the presence of periostin in the context of rotator cuff tear (RCT). 55 consecutive patients with RCT were enrolled. Immunohistochemical periostin detection was performed on tissue samples excised from tear margins. Our study documented the presence of periostin in the margins of RCT. It is plausible that, when a tear occurs, multiple stimuli, both mechanical and inflammatory, lead to the development of a periostin-rich microenvironment as an attempt to tendon healing.

The native coronal orientation of tibial plateaus may limit the indications to perform a kinematic aligned total knee arthroplasty.

PURPOSE: To investigate the coronal alignment of tibial plateaus in normal and osteoarthritic knees and to simulate the effects of a tibial cut performed in total knee arthroplasty (TKA) using a kinematic alignment technique with standard instrumentation. METHODS: The coronal alignment of tibial plateaus was measured in three groups including group 1 (reference group), 50 cadaveric tibiae showing no evidence of degenerative changes of tibial plateaus; group 2, 49 patients who underwent MR of the knee, showing no or mild degenerative changes of the knee joint and, group 3, 54 patients with knee osteoarthritis who underwent computer-assisted total knee arthroplasty. RESULTS: The coronal alignment of tibial plateaus averaged 2.4° with no significant differences between groups. The mean coronal orientation of tibial plateaus was 3° ± 2° in men and 1.6° ± 2° in women (p = 0.03). A coronal alignment of tibial plateaus of 3° or more was found in 69 cases (45%) and 5° or more in 23 (14.7%). The simulation of a tibial cut performed with an error of 3° in varus in 15% of the subjects showing a native coronal orientation of tibial plateaus of 3° or more, led to a final tibial cut greater 6° in 13.7% of cases. CONCLUSIONS: A coronal alignment of tibial plateaus of 3° or more in varus was found in near half of normal subjects and osteoarthritic patients. A preoperative measurement of the coronal alignment of tibial plateaus is advisable in any patients scheduled for kinematic aligned TKA. As errors in the alignment of the tibial component of 3° or more may occur using standard instrumentations, the results of this study raise questions on performing a kinematic aligned TKA with standard instrumentations. LEVEL OF EVIDENCE: IV.