The efficacy of dual-mobility cup in preventing dislocation after total hip arthroplasty: a systematic review and meta-analysis of comparative studies.

PURPOSE: Although long-term reports of total hip arthroplasty (THA) showed successful results, instability remains a major complication. Recently, dual-mobility cups (DMC) have gained more and more interest among clinicians, with encouraging results in terms of lower rate of dislocation associated with good clinical results, but a lack of evidence exists regarding the real efficacy of this implant design compared to traditional fixed-bearing total hip arthroplasties. METHODS: A systematic search was performed in PubMed, Google scholar, Cochrane Library, and EMBASE by two independent reviewers for comparative studies available till December 2017, with the primary objective to demonstrate a real lower dislocation rate of DMC implants compared to unipolar fixed-bearing cup designs. A meta-analysis was conducted with the collected pooled data about dislocation rate, calculating the risk difference (RD) and relative risk (RR) with 95% CI for dichotomous variables. Heterogeneity was tested using the χ2 and Higgins' I2 tests. A fixed-effect model was used because the statistical heterogeneity was below 50%. RESULTS: After performing a critical exclusion process, the number of eligible studies included for final synthesis considered was 15, describing the results of a total of 2408 total hip arthroplasties (50.6% with a dual-mobility acetabular cup design, 49.4% with a standard fixed-bearing design). The fixed-effect meta-analysis showed a slight significant risk ratio of 0.16 (95% CI, 0.09, 0.28; I2 = 0%, p < 0.00001); a statistically significant difference in favor of the DMC group was maintained also considering only primary or revision arthroplasties, traumatic fractures or elective patients with diagnosis of osteoarthritis, avascular osteonecrosis or rheumatic arthritis. CONCLUSIONS: With the intrinsic limitations of our study design and based on the current available data, this study demonstrates that dual-mobility acetabular components decrease the risk of post-operative instability also in high-risk patients, both in primary and revision hip arthroplasties. However, new high-quality studies, possibly with a randomized control design, should be undertaken in order to strengthen the present data. STUDY DESIGN: Level of Evidence III, therapeutic study.

Physical exam of the adolescent shoulder: tips for evaluating and diagnosing common shoulder disorders in the adolescent athlete.

PURPOSE OF REVIEW: In the young athlete, the shoulder is one of the most frequently injured joints during sports activities. The injuries are either from an acute traumatic event or overuse. Shoulder examination can present some challenges; given the multiple joints involved, the difficulty palpating the underlying structures, and the potential to have both intra- and/or extra-articular problems. RECENT FINDINGS: Many of the shoulder examination tests can be positive in multiple problems. They usually have high sensitivity but low specificity and therefore low predictive value. The medical history coupled with a detailed physical exam can usually provide the information necessary to obtain an accurate diagnosis. A proficient shoulder examination and the development of an adequate differential diagnosis are important before considering advanced imaging. SUMMARY: The shoulder complex relies upon the integrity of multiple structures for normal function. A detailed history is of paramount importance when evaluating young athletes with shoulder problems. A systematic physical examination is extremely important to guiding an accurate diagnosis. The patient's age and activity level are very important when considering the differential diagnosis. Findings obtain through history and physical examination should dictate the decision to obtain advanced imaging of the shoulder.

Focal osteonecrosis in the femoral head following stable anatomic fixation of displaced femoral neck fractures.

INTRODUCTION: Femoral head (FH) osteonecrosis (ON) and subsequent segmental collapse is a major concern following displaced femoral neck fractures (FNF). We aimed to quantify residual perfusion to the FH following FNF and evaluate the viability of the FH overtime after surgical fixation. MATERIALS AND METHODS: Twenty-three patients with FNF underwent dynamic contrast-enhanced (DCE)-MRI to estimate bone perfusion in the FH, using the contralateral side as control. Following open anatomic reduction and a length/angle-stable fixation, a special MRI sequence evaluated the FH for ON changes over time at 3 and 12 months after surgery. RESULTS: We found significant compromise of both arterial inflow [83.1%-initial area under the curve (IAUC) and 73.8%-peak) and venous outflow (243.2%-elimination rate (K el)] in the FH of the fractured side. The supero-medial quadrant suffered the greatest decrease in arterial inflow with a significant decrease of 71.6% (IAUC) and 68.5% (peak). Post-operative MRI revealed a high rate (87%-20/23) of small ON segments within the FH, and all developed in the anterior aspect of the supero-medial quadrants. Fracture characteristics, including subcapital FNF, varus deformity, posterior roll-off ≥20° and Pauwel's angle of 30°-50° demonstrated a greater decrease in perfusion compared to contralateral controls. CONCLUSION: FNF significantly impaired the vascular supply to the FH, resulting in high incidence of small ON segments in the supero-medial quadrant of the FH. However, maintained perfusion, probably through the inferior retinacular system, coupled with urgent open anatomic reduction and stable fixation resulted in excellent clinical and radiographic outcomes despite a high rate of small ON segments noted on MRI. LEVEL OF EVIDENCE: Level I: Prognostic Investigation.

Comminuted olecranon fractures: biomechanical testing of locked versus minifragment non-locked plate fixation.

INTRODUCTION: Open reduction and internal fixation has long been accepted as optimal treatment for displaced olecranon fractures based on poor results seen with conservative management. With the presence of comminution, tension-band wiring constructs are contraindicated due to tendency to compress through fragments, thereby shortening the articular segment. Therefore, plate fixation is typically employed. Our hypothesis was that in a comminuted fracture model, 2.7 mm reconstruction plating without locking screws will perform equally to 3.5 mm locked plating in terms of fracture displacement and rotation (shear). MATERIALS AND METHODS: A three-part comminuted olecranon fracture pattern was created in nine matched pairs of cadaveric specimen using an oscillating saw in standardized, reproducible fashion. Each matched pair was then randomized to receive either 2.7 mm reconstruction plating or 3.5 mm proximal ulna locked plating. Random allocation software was used to assign the 2.7 mm plate construct to either the right or left side of each pair with the contralateral receiving the 3.5 mm plate construct. Specimens were cyclically loaded simulating passive range of motion exercises commonly performed during rehabilitation. Displacement and rotation in relation to the long axis of the ulna were measured through motion capture. Fragment gapping and rotation was quantified following 100 cycles at 10 N and again following 100 cycles at 500 N. RESULTS: No significant differences were detected between the 2.7 and 3.5 mm plates in fracture rotation or gapping following loads at 10 N (0.5° and 0.7°; 0.6 and 1.2 mm; respectively; p > 0.05) or 500 N (2.3° and 1.6°; 3.8 and 3.1 mm; respectively; p > 0.05) loading. Fragment rotation and gapping were positively correlated within each plate construct (R 2 > 0.445; p < 0.05). CONCLUSIONS: 2.7 mm plating is an alternative to 3.5 mm locked plating with decreased plate prominence without significantly sacrificing displacement and rotational control. This is beneficial in fracture patterns where the traditional dorsal plating does not offer optimal screw trajectory.

Surgical options for anterior cruciate ligament reconstruction in the young child.

Injury to the anterior cruciate ligament (ACL) is becoming increasingly common in the skeletally immature population. Historically, there was a reluctance to operate on skeletally immature patients due to potential damage to the physis and subsequent growth disturbances; however, more recently, ACL reconstruction techniques specifically developed for this young population have shown good outcomes and low complication rates. In this article, we briefly discuss the modifiable and non-modifiable risk factors for ACL injury in children, options for conservative management for ACL rupture, and outcomes for delayed operative management. The main focus of the manuscript is to describe three operative technique options designed for ACL reconstruction in skeletally immature patients and to review the literature on outcomes and complications of these techniques. Two of these techniques, namely the Modified MacIntosh and the all-epiphyseal techniques, are often referred to as physeal-sparing, while the third, i.e. the transphyseal technique, is not. While different in approach and technique, these procedures have been shown to produce good outcomes and minimal complications in the skeletally immature population. Despite these positive reports, it is also essential to be aware of potential complications and the potential risk of recurrence.

Quantitative assessment of patellar vascularity following bone-patellar tendon-bone autograft harvest for ACL reconstruction.

PURPOSE: Recent anatomic studies have suggested that the dominant arterial supply of the patella enters through the inferior pole. Based upon these findings, we hypothesized that bone-patellar tendon-bone graft harvest can significantly diminish patellar vascularity. METHODS: Nine matched pair cadaveric knee specimens (mean age 47.4 years) were dissected and cannulated. A single knee was selected to undergo routine graft harvest, and the contralateral knee was left intact to serve as a control. Gadolinium was injected, and magnetic resonance imaging (MRI) signal enhancement was quantified to determine differences in uptake. Each matched pair was subsequently injected with a urethane polymer compound and dissected to correlate vessel disruption with MRI findings. RESULTS: We identified two predominating patterns of vessel entry. In one pattern, the vessel entered the inferomedial aspect (five o'clock/right, seven o'clock/left) of the patella and was disrupted by graft harvest in 2/9 (22.2 %) pairs. In the second pattern, the vessel entered further medial (four o'clock/right, eight o'clock/left) and was not disrupted (7/9, 78.8 %). The mean decrease in gadolinium uptake following disruption of the predominant vessel measured 56.2 % (range 42.6-69.5 %) compared to an average decrease of 18.3 % (range 7.1-29.1 %) when the dominant arterial supply to the inferior pole remained intact (p < 0.04). CONCLUSION: Medial entry of the predominant vessel precluded vessel disruption. Disruption of the dominant arterial supply can result in a significant decrease in patellar vascularity. Modification of graft harvest techniques and areas of surgical dissection should be explored to minimize vascular insult. Further correlation with clinical studies/outcomes is necessary to determine a potential association between vascular insult and anterior knee pain.

Dislocation is a risk factor for poor outcome after supination external rotation type ankle fractures.

INTRODUCTION: Ankle fractures are one of the most common fractures requiring surgical treatment. Ankle fracture-dislocations are significant injuries to the osseous and soft tissue envelope, but studies focused on the effect of dislocation on radiographic and functional outcomes are lacking. The objective of this study was to evaluate the effect of dislocations on postoperative outcomes in SER IV ankle fracture patients. MATERIALS AND METHODS: From 2004 through 2010, all operative SER IV ankle fractures treated by a single surgeon were enrolled in a prospective database. SER IV ankle fractures were separated into two groups based on clinical or radiographic evidence of dislocation. The primary and secondary functional outcomes measures were the Foot and Ankle Outcome Score (FAOS) and ankle and subtalar range of motion (ROM) with a minimum of 1-year follow-up, respectively. RESULTS: 108 patients with SER IV ankle fractures were identified, with 73 in the non-dislocation group (68%) and 35 patients in the dislocation group (32%). Patient demographics and co-morbidities were similar between the two groups. The incidence of open fractures and the application of an external fixator were significantly higher in the dislocation group (p = 0.037 and p = 0.003, respectively). The dislocation group showed a significant decrease in the accuracy of articular reduction (p = 0.003). At a mean follow-up of 21 months, ankle fracture-dislocation patients had increased pain (p = 0.005) and decreased activities of daily living (p = 0.014) on FAOS outcome measures and significantly worse ankle and subtalar ROM. CONCLUSIONS: The results of this study suggest that concurrent dislocation at time of ankle fracture is associated with worse radiographic and functional outcomes, but not an increase in superficial or deep infection. The results from this study may be helpful in counseling patients regarding expected clinical outcomes after ankle fracture-dislocation and in the surgical management of this complex injury.

Regional analysis of femoral head perfusion following displaced fractures of the femoral neck.

PURPOSE: To assess regional variations in the arterial and venous blood supply to the femoral head following displaced fracture of the femoral neck using dynamic contrast enhanced (DCE)-MRI quadrant analysis. MATERIALS AND METHODS: A total of 27 subjects with displaced femoral neck fractures were enrolled in the study. Quadrant specific DCE-MRI perfusion analysis was performed on a 1.5 Tesla MRI scanner. Simultaneous imaging of control and displaced fractured hips was done for comparison. RESULTS: Quadrant specific decreases were found in the arterial (A (0.52 versus 0.27; P = 5.7E-13), Akep (1.0/min(-1) versus 0.41/min(-1) ; P = 1.3E-9) and venous (kel (0.05/min(-1) versus -0.02/min(-1) ; P = 5.1E-5) supply to the femoral head between control and injured sides using a two-factor analysis of variance test. The fractional perfusion (initial area under the curve) in the supero/inferolateral quadrants was 49% min/54% min, in the supero/inferomedial quadrants was 43% min/46% min and for the total femoral head was 39% min on the fracture versus control sides. CONCLUSION: Quadrant specific decreases in arterial and venous perfusion on the fracture side were observed when compared with control.

Geriatric proximal humeral fracture patients show similar clinical outcomes to non-geriatric patients after osteosynthesis with endosteal fibular strut allograft augmentation.

BACKGROUND: Osteosynthesis of proximal humeral fractures is challenging in geriatric patients. The purpose of this investigation was to compare postoperative clinical outcomes between cohorts of geriatric (aged ≥65 years) and non-geriatric proximal humeral fracture patients treated via locked plating with endosteal fibular strut allograft augmentation. METHODS: From March 2007 to January 2013, 71 adult patients with 2-, 3-, and 4-part proximal humeral fractures according to the Neer classification underwent osteosynthesis with locked plating and fibular allograft augmentation and had at least 12 months of clinical follow-up. All patients followed the same postoperative rehabilitation protocol. We compared the following between geriatric and non-geriatric patients: Disabilities of the Arm, Shoulder and Hand scores; University of California, Los Angeles shoulder ratings; Constant-Murley scores; and range of motion; as well as injury characteristics and radiographic outcomes. RESULTS: Geriatric patients comprised 48% of the study cohort (34 of 71 patients). The mean age of the geriatric and non-geriatric cohorts was 74 years and 53 years, respectively. Geriatric patients showed significantly reduced forward flexion (147° vs 159°, P = .04) when compared with non-geriatric patients. There were no significant differences in functional scores, radiographic outcomes, or complication rates between the 2 cohorts, although in 1 geriatric patient, osteonecrosis developed and screw penetration through the collapsed head was present 3 years after surgery. CONCLUSIONS: Osteosynthesis of proximal humeral fractures via locked plating with fibular strut allograft augmentation results in similar clinical outcomes between geriatric and non-geriatric patients. We believe that enhanced stability provided by this fixation construct allows early intensive postoperative therapy and results in excellent outcomes despite patient age.

The effect of antegrade femoral nailing on femoral head perfusion: a comparison of piriformis fossa and trochanteric entry points.

INTRODUCTION: Piriformis fossa entry antegrade femoral nailing is a common method for stabilizing diaphyseal femur fractures. However, clinically significant complications such as chronic hip pain, hip abductor weakness, heterotopic ossification and femoral head osteonecrosis have been reported. A recent cadaveric study found that piriformis entry nailing damaged either the deep branch of the medial femoral circumflex artery (MFCA) or its distal superior retinacular artery branches in 100% of specimens and therefore recommended against its use. However, no study has quantitatively assessed the effect of different femoral entry points on femoral head perfusion. MATERIALS AND METHODS: Twelve fresh-frozen cadaveric lower extremity specimens were randomly allocated to either piriformis fossa or trochanteric entry nailing using a 13-mm reamer. The contralateral hip served as an internal matched control. All specimens subsequently underwent gadolinium-enhanced fat-suppressed gradient-echo sequence MRI to assess femoral head perfusion. Gross dissection was also performed to assess MFCA integrity and distance to the opening reamer path. RESULTS: MRI quantification analysis revealed near full femoral head perfusion with no significant difference between the piriformis and trochanteric starting points (95 vs. 97%, p = 0.94). There was no observed damage to the deep MFCA in either group. The mean distance from the reamer path to the deep MFCA was 3.2 mm in the piriformis group compared to 18.5 mm in the trochanteric group (p = 0.001). Additionally, there was a significantly greater number of mean terminal superior retinacular vessels damaged by the opening reamer in the piriformis cohort (1 vs. 0; p = 0.007). CONCLUSIONS: No statistically significant difference in femoral head perfusion was found between the two groups. Therefore, we cannot recommend against the use of piriformis entry femoral nails. However, we caution against multiple errant starting point attempts and recommend meticulous soft tissue protection during the procedure.

Contributions of the Abductor Muscles to Rotational and Distractive Stability of the Hip in a Biomechanical Cadaveric Model.

Background: The gluteus minimus (GMin) and gluteus medius (GMed) are important dynamic stabilizers of the hip, but quantitative data on their biomechanical roles in stabilizing the hip are currently lacking. Purpose: To (1) establish a reproducible biomechanical cadaveric model of the hip abductor complex and (2) characterize the effects of loading the GMin and GMed on extraneous femoral rotation and distraction. Study Design: Controlled laboratory study. Methods: A total of 10 hemipelvises were tested in 4 muscle loading states: (1) unloaded, (2) the GMin loaded, (3) the GMed loaded, and (4) both the GMin and GMed loaded. Muscle loads were applied via cables, pulleys, and weights attached to the tendons to replicate the anatomic lines of action. Specimens were tested under internal rotation; external rotation; and axial traction forces at 0°, 15°, 30°, 60°, and 90° of hip flexion. Results: When loaded together, the GMin and GMed reduced internal rotation motion at all hip flexion angles (P < .05) except 60° and reduced external rotation motion at all hip flexion angles (P < .05) except 0°. Likewise, when both the GMin and GMed were loaded, femoral distraction was decreased at all angles of hip flexion (P < .05). Conclusion: The results of this study demonstrated that the GMin and GMed provide stability against rotational torques and distractive forces and that the amount of contribution depends on the degree of hip flexion. Clinical Relevance: Improved understanding of the roles of the GMin and GMed in preventing rotational and distractive instability of the hip will better guide treatment of hip pathologies and optimize nonoperative and operative therapies.

Complications following treatment of supination external rotation ankle fractures through the posterolateral approach.

BACKGROUND: The posterolateral approach to the ankle is a valuable approach for the treatment of ankle fractures (SER) ankle fractures. The purpose of this study was to determine the complication rate for ankle fractures treated through the posterolateral approach. We hypothesized that this approach would be associated with a low incidence of complications and good clinical outcomes. METHODS: A total of 112 patients with SER ankle fractures treated through a posterolateral approach met inclusion criteria. Prospectively collected data were examined retrospectively from chart review, preoperative plain radiographs, and MRI as well as postoperative radiographs. The mean age was 51.5 (range, 18 to 86) years. The primary outcome of the study was major (surgical debridement, flap, or split thickness skin graft) and minor (epidermolysis requiring local wound care) wound complications. The secondary outcomes included infection, symptomatic hardware, reoperation, loss of reduction, malreduction, nonunion, Foot and Ankle Outcome Scores, range of motion, and other perioperative complications. RESULTS: There were 11 minor wound related complications (9.8%) and 3 major wound complications (2.7%), 1 of which required a split thickness skin graft. The overall postoperative wound infection rate was 4.4% (5 of 112); 2 patients required hardware removal due to deep infection. Of patients, 7% (8 of 112) reported symptomatic lateral sided hardware and thus underwent removal of implants. The overall reoperation rate was 12.5%. The complication rate was 23%. No patients experienced loss of reduction. CONCLUSIONS: The posterolateral approach to the ankle was a valuable approach for SER ankle fractures. This series demonstrated many key aspects of this approach including access to the apex of the fibula fracture for posterior antiglide plating, access to the posterior malleolus for fixation, access to the posterior inferior tibiofibular ligament for repair, minimal major wound complications, good functional outcomes, and minimal need for reoperation.

Comparison of supination external rotation type IV ankle fractures in geriatric versus nongeriatric populations.

BACKGROUND: Geriatric patients' (defined as those older than 65 years old) inherent comorbidities, functional limitations, and bone quality present obstacles to successful clinical outcomes for operatively treated supination external rotation (SER) ankle fractures. We retrospectively reviewed a prospectively collected series of SER injuries between 2004 and 2010. This is a comparison of the radiographic and clinical outcomes of our geriatric (27 patients) and nongeriatric (81 patients) populations. We hypothesized that geriatric patients would have worse outcomes when compared to nongeriatric patients. METHODS: All SER ankle fractures (176) treated by a single surgeon were enrolled in a prospective database. All patients fulfilled inclusion criteria (108) consisting of 1 year of having clinical follow-up, postoperative radiographs, and Foot & Ankle Outcome Scores (FAOS). The primary outcome evaluated was functional outcome as exhibited by the FAOS. The secondary outcomes included adequacy of reduction, loss of reduction, postoperative complications (wound complications, infection, pain-driven hardware removal), and range of motion. RESULTS: Despite significantly higher rates of diabetes (P < .001) and peripheral vascular disease (P < .001), there were statistically significantly better FAOS outcomes in the symptoms subcategory among the geriatric population. There was no significant difference in the articular reduction, syndesmotic reduction, wound complications, postoperative infections, or range of motion between these groups. CONCLUSION: Geriatric patients exhibited equivalent complication rates, radiographic outcomes, and functional outcomes compared to nongeriatric patients in this series. Anatomic fixation and soft tissue management counter the inherent risks of operative intervention in geriatric populations that report higher rates of comorbidities. This study supports aggressive fracture- and ligament-specific operative intervention in geriatric patients presenting with unstable SER injuries.

Femoral Head Vascularity After Arthroscopic Femoral Osteochondroplasty: An In Vivo Dynamic Contrast-Enhanced MRI Study.

Background: A serious concern with surgical procedures around the hip joint is iatrogenic injury of the arterial supply to the femoral head (FH) and consequent development of FH osteonecrosis. Cam-type morphology can extend to the posterosuperior area. Understanding the limit of the posterior superior extension of the femoral osteochondroplasty is paramount to avoid underresection and residual impingement while maintaining FH vascularity. Purpose/Hypothesis: The aim of this study was to quantify the impact of arthroscopic femoral osteochondroplasty on the FH vascular supply. It was hypothesized that keeping the superior extension of the resection zone anterior to the 12-o'clock position would maintain FH vascularity. Study Design: Case series; Level of evidence, 4. Methods: Ten adult patients undergoing arthroscopic femoroacetabular impingement (FAI) surgery were included in the study. Computed tomography (CT) scans were obtained before and after arthroscopic osteochondroplasty to define the extension of resection margins. To quantify FH vascularity, postoperative dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) was obtained at 2 time points: immediately after surgery and at the 3-month follow-up. Custom MRI analysis software was used to quantify perfusion. Results: CT scan analysis demonstrated that the superior resection margin was maintained anterior to the 12-o'clock position in half of the patients. The remining 5 patients had a mean posterior extension of 11.4° ± 7.5°. The immediate postoperative DCE-MRI revealed diminished venous outflow in the operative side but no difference in overall FH perfusion. At the 3-month follow-up DCE-MRI, there was no perfusion difference between the operative and nonoperative FHs. Conclusion: This study provides previously unreported quantitative MRI data on in vivo perfusion of the FH after the commonly performed arthroscopic femoral osteochondroplasty for the treatment of cam-type FAI. Maintaining resection margins anterior to the 12-o'clock position, or even 10° posteriorly, was not observed to impair perfusion to the FH.

Differential regional perfusion of the human anterior cruciate ligament: quantitative magnetic resonance imaging assessment.

PURPOSE: Surgical reconstruction is the current standard for ACL rupture treatment in active individuals. Recently, there is renewed interest in primary repair of proximal ACL tears. Despite this, ACL biology and healing potential are currently not well understood. Vascularity is paramount in ACL healing; however, previous ACL vascularity studies have been limited to qualitative histological and dissection-based techniques. The study objective was to use contrast-enhanced quantitative-MRI to compare relative perfusion of proximal, middle, and distal thirds of the in situ ACL. We hypothesized perfusion would be greatest in the proximal third. METHODS: Fourteen cadaveric knees were studied (8 females, 6 males), age 25-61 years. Superficial femoral, anterior tibial, and posterior tibial arteries were cannulated; without intraarticular dissection. Contrast-enhanced quantitative-MRI was performed using a previously established protocol. ACL regions corresponding to proximal, middle, and distal thirds were identified on sagittal-oblique pre-contrast images. Signal enhancement (normalized to tibial plateau cartilage) was quantified to represent regional perfusion as a percentage of total ACL perfusion. Comparative statistics were computed using repeated measures ANOVA, and pairwise comparisons performed using the Bonferroni method. RESULTS: Relative perfusion to proximal, middle, and distal ACL zones were 56.0% ±17.4%, 28.2% ±14.6%, and 15.8% ±16.3%, respectively (p = 0.002). Relative perfusion to the proximal third was significantly greater than middle (p = 0.007) and distal (p = 0.001). No statistically relevant difference in relative perfusion was found to middle and distal thirds (p = 0.281). Post-hoc subgroup analysis demonstrated greater proximal perfusion in males (66.9% ± 17.3%) than females (47.8% ± 13.0%), p = 0.036. CONCLUSION: Using quantitative-MRI, in situ adult ACL demonstrated greatest relative perfusion to the proximal third, nearly 2 times greater than the middle third and 3 times greater than the distal third. Knowledge of differential ACL vascular supply is important for understanding pathogenesis of ACL injury and the process of biological healing following various forms of surgical treatment.

Vascularity of the early post-natal human distal femoral chondroepiphysis: Quantitative MRI analysis.

Purpose: Injury to or abnormality of developing distal femoral chondroepiphysis blood supply has been implicated in osteochondritis dissecans development. Progressive decrease in epiphyseal cartilage blood supply occurs in normal development; however, based on animal studies, it is hypothesized that there is greater decrease in regions more prone to osteochondritis dissecans lesions. We aimed to quantify differential regional perfusion of the immature distal femoral chondroepiphysis. We hypothesized there is decreased perfusion in the lateral aspect of the medial femoral condyle, the classic osteochondritis dissecans lesion location. Methods: Five fresh-frozen human cadaveric knees (0-6 months old) were utilized. The superficial femoral artery was cannulated proximally and contrast-enhanced magnetic resonance imaging performed using a previously reported protocol for quantifying osseous and soft tissue perfusion. Regions of interest were defined, and signal enhancement changes between pre- and post-contrast images, normalized to background muscle, were compared. Results: When comparing average normalized post-contrast signal enhancement of whole condyles, as well as distal, posterior, and inner (toward the notch) aspects of the medial and lateral condyles, no significant perfusion differences between condyles were found. In the medial condyle, no significant perfusion difference was found between the medial and lateral aspects. Conclusion: We quantified immature distal femoral chondroepiphysis regional vascularity in the early post-natal knee. In specimens aged 0-6 months, no distinct watershed region was detected. Despite possible limitations, given small sample size, as well as resolution of magnetic resonance imaging and analysis, our results suggest the hypothesized vascular abnormality predisposing osteochondritis dissecans either does not occur universally or occurs after this developmental age.

Proximal Overresection During Femoral Osteochondroplasty Negatively Affects the Distractive Stability of the Hip Joint: A Cadaver Study.

BACKGROUND: Contact between the acetabular labrum and articular cartilage of the femoral head creates a suction seal that helps maintain stability of the femoral head in the acetabulum. A femoral osteochodroplasty may occasionally extend proximally into the femoral head, diminishing the articular surface area available for sealing contact. PURPOSE: To determine whether proximal overresection decreases the rotational and distractive stability of the hip joint. STUDY DESIGN: Controlled laboratory study. METHODS: Six hemipelvises in the following conditions were tested: intact, T-capsulotomy, osteochondroplasty to the physeal scar, and 5- and 10-mm proximal extension. The pelvis was secured to a metal plate, and the femur was potted and attached to a multiaxial hip jig. Specimens were axially distracted using a load from 0 to 150 N. For rotational stability testing, 5 N·m of internal and external torque was applied. Both tests were performed at different angles of flexion (0°, 15°, 30°, 60°, 90°). Displacement and rotation were recorded using a 3-dimensional motion tracking system. RESULTS: The T-capsulotomy decreased the distractive stability of the hip joint. A femoral osteochondroplasty up to the physeal scar did not seem to affect the distractive stability. However, a proximal extension of the resection by 5 and 10 mm increased axial instability at every angle of flexion tested, with the greatest increase observed at larger angles of flexion (P < .01). External rotation increased significantly after T-capsulotomy in smaller angles of flexion (0°, P = .01; 15°, P = .01; 30°, P = .03). Femoral osteochondroplasty did not create further external rotational instability, except when the resection was extended 10 mm proximally and the hip was in 90° of flexion (P = .04). CONCLUSION: This cadaveric study demonstrated that proximal extension of osteochondroplasty into the femoral head compromises the distractive stability of the hip joint but does not affect hip rotational stability. CLINICAL RELEVANCE: Clinically, this study highlights the importance of accuracy when performing femoral osteochondroplasty to minimize proximal extension that may increase iatrogenic instability of the hip joint.

Quantitative assessment of the vascularity of the skeletally immature patella: a cadaveric study using MRI.

PURPOSE: While predominant blood supply to the adult patella enters inferomedially, little is known about skeletally immature patellar perfusion. Improved knowledge of immature patella vascularity can further understanding of osteochondritis dissecans, dorsal defects of the patella and bipartite patella, and help ensure safe surgical approaches. We hypothesized that the immature patella would exhibit more uniform blood flow. The study purpose was to quantify immature patella regional perfusion in comparison with adults. METHODS: Ten cadaveric knees were utilized (five immature, five mature). The superficial femoral artery was cannulated proximally. Signal enhancement increases were compared from pre- to post-contrast MRI to assess relative arterial contributions to patella regions (quadrants, anterior/posterior, superior/inferior, medial/lateral, and outer/inner). RESULTS: Quantitative-MRI analysis revealed similar distribution of enhancement between the immature and mature patella. The inferior pole exhibited significantly higher arterial contribution versus superior pole in both immature and mature groups (p = 0.009; both groups), while the inferomedial quadrant had the highest arterial contribution of all quadrants in both groups. The superolateral quadrant demonstrated the lowest arterial contribution in the immature group and second lowest in the adult group. The patella outer periphery had significantly greater arterial contribution than the inner central region in both immature (p = 0.009) and mature (p = 0.009) groups. CONCLUSION: Distribution of arterial contributions between the immature and mature patella was similar. Our results highlight the importance of inferior and inferomedial blood supply in both immature and mature patellas. These findings have implications for paediatric and adult patients; surgical damage to inferior patellar vessels should be avoided to prevent associated complications.

Increased Vascularity in the Neonatal versus Adult Meniscus: Evaluation with Magnetic Resonance Imaging.

Objective. Quantification of meniscus vascularity has been limited with previous techniques, and minimal data exist describing differential vascular zones in the skeletally immature meniscus. The objective of this study is to use quantitative contrast-enhanced magnetic resonance imaging (MRI) to compare meniscal vascularity in neonatal specimens with adults. We hypothesized that the developing meniscus has greater and more uniform vascularity throughout all zones. Design. Ten fresh-frozen human cadaveric knees (5 neonatal, age 0-6 months; 5 adult, 34-67 years) underwent gadolinium-enhanced MRI using an established vascularity quantification protocol. Regions of interest corresponding to peripheral and central zones of the meniscus were identified on pre-contrast coronal images, and signal enhancement within the same regions (normalized against background tissue) was compared between pre- and post-contrast images. Results. The medial and lateral menisci had similar distribution of perfusion (45.8% ± 8.1% medial vs. 54.2% ± 8.1% lateral in neonatal knees; 50.6% ± 11.3% medial vs. 49.4% ± 11.3% lateral in adult knees, P = 0.47). Increased perfusion was demonstrated in the periphery compared with the central zone (2.3:1 in neonatal knees and 3.25:1 in adult knees, P = 0.31). Neonatal specimens demonstrated 6.0-fold greater overall post-contrast meniscal signal enhancement compared with adults (P < 0.0001), with the 0-month specimen demonstrating the greatest proportional signal enhancement. Conclusions. While blood flow to the periphery is greater than to central zones in all menisci, younger menisci receive proportionally greater overall blood flow compared to adults, including to the central zone, suggesting that the immature meniscus is a more biologically active tissue than its adult counterpart.

The Use of Bone Marrow Concentrate in the Treatment of Full-Thickness Chondral Defects.

This article is a critical analysis of a study, "Minimally Manipulated Bone Marrow Concentrate Compared with Microfracture Treatment of Full-Thickness Chondral Defects: A One-Year Study in an Equine Model," by Chu et al. (J Bone Joint Surg Am. 100(2):138-146, 2018). The investigation compared two interventions in the management of full-thickness chondral defects in an equine model: autologous bone marrow concentrate without concomitant microfracture treatment versus microfracture treatment alone. This review analyzes the methodology and results of their investigation and examines how their findings may influence the continued development of therapeutic options for full-thickness cartilage injuries. The study utilized in vitro analysis, arthroscopic assessment, magnetic resonance imaging (MRI) evaluation, and histological analysis to compare the treatments and their influence on the quality of cartilage repair. Although Chu et al. reported similar results between groups, their findings offer insight into the role of arthroscopy, MRI, and histology in the evaluation of repair quality. We compare their findings to those of similar investigations, highlighting the limited therapeutic options and variable clinical outcomes related to the treatment of full-thickness articular cartilage defects.