Atrophic non-unions are usually attributed to impaired blood supply but the events that lead to atrophic non-union remain poorly understood. Recent studies. 1,. 2. have shown that vascularity is not reduced in established non-unions but these studies have not examined vascularity at an early stage. The aims of this study were to: 1) develop and validate a clinically relevant small animal model of atrophic non-union and 2) test the hypothesis that the vessel density of atrophic non-unions reaches that of normal healing bones but at a later time point. Twenty eight adult female Wistar rats underwent application of a novel circular frame external fixator to the right tibia under general anaesthesia. The fixator construct was standardised, with eight needles that were drilled through the skin into the proximal and distal metaphyses of the tibia. An osteotomy was performed with a 1mm burr under irrigation. The periosteum was removed on 14 of the 28 animals using a scalpel and the intramedullary canal was curetted. Both insults were performed proximally and distally for a distance equivalent to 1 diameter of the tibia. A 1mm gap was introduced at the osteotomy site and the wound was closed. Once the animal had recovered it was allowed unrestricted weight bearing. Anteroposterior X rays were performed every 2 weeks. Animals were killed at 1, 3, 8 and 16 weeks. Callus areas were measured from X rays using an image analysis system. The average callus area was calculated for each rat every 2 weeks as an indicator of callus production. Specimens were fixed, decalcified, embedded in paraffin wax and 6 ìm sections were stained with H& E. Vascularity was assessed immunohistochemically with monoclonal antibody against smooth muscle actin. The total number of blood vessels in the interfragmentary gap was counted. At 8 and 16 weeks post-osteotomy all animals where stripping and curetting had been performed went on to an atrophic non-union. All animals where this was not performed went on to unite successfully. Histological observations support these radiological findings. Significantly less callus formed in the non-unions than in those that united. There were significantly fewer vessels in the non-unions at week 1 compared to the controls but, by 8 weeks the blood vessel density in the established atrophic non-unions had reached the same level as the vessel density during normal healing. An atrophic non-union model that closely resembles the clinical situation has been developed and validated in rats. The results support the hypothesis that the number of vessels in atrophic non-unions reaches the same level as in those that unite but at a later time point. It is concluded that diminished vessel density within the first 3 weeks may prevent fractures from uniting

Dual plating of the medial and lateral distal femur has been proposed to reduce angular malunion and hardware failure secondary to delayed union or nonunion. This strategy improves the strength and alignment of the construct, but it may compromise the vascularity of the distal femur paradoxically impairing healing. This study investigates the effect of dual plating versus single plating on the perfusion of the distal femur.

Ten matched pairs of fresh-frozen cadaveric lower extremities were assigned to either isolated lateral plating or dual plating of a single limb. The contralateral lower extremity was used as a matched control. A distal femoral locking plate was applied to the lateral side of ten legs using a standard sub-vastus approach. Five femurs had an additional 3.5mm reconstruction plate applied to the medial aspect of the distal femur using a medial sub-vastus approach.

The superficial femoral artery and the profunda femoris were cannulated at the level of the femoral head. Gadolinium MRI contrast solution (3:1 gadolinium to saline ration) was injected through the arterial cannula. High resolution fat-suppressed 3D gradient echo sequences were completed both with and without gadolinium contrast. Intra-osseous contributions were quantified within a standardized region of interest (ROI) using customized IDL 6.4 software (Exelis, Boulder, CO). Perfusion of the distal femur was assessed in six different zones. The signal intensity on MRI was then quantified in the distal femur and comparison was made between the experimental plated limb and the contralateral, control limb. Following completion of the MRI protocol, the specimens were injected with latex medium and the extra-osseous vasculature was dissected.

Quantitative MRI revealed that application of the lateral distal femoral locking plate reduced the perfusion of the distal femur by 21.7%. Within the dual plating group there was a reduction in perfusion by 24%. There was no significant difference in the perfusion between the isolated lateral plate and the dual plating groups. There were no regional differences in perfusion between the epiphyseal, metaphyseal or meta-diaphyseal regions.

Specimen dissection in both plating groups revealed complete destruction of any periosteal vessels that ran underneath either the medial or lateral plates. Multiple small vessels enter the posterior condyles off both superior medial and lateral geniculate arteries and were preserved in all specimens. Furthermore, there was retrograde flow to the distal most aspect of the condyles medially and laterally via the inferior geniculate arteries. The medial vascular pedicle was proximal to the medial plate in all the dual plated specimens and was not disrupted by the medial sub-vastus approach in any specimens.

Fixation of the distal femur via a lateral sub-vastus approach and application of a lateral locking plate results in a 21% reduction in perfusion to the distal femur. The addition of a medial 3.5mm reconstruction plate does not significantly compromise the vascularity of the distal femur. The majority of the vascular insult secondary to open reduction, internal fixation of the distal femur occurs with application of the lateral locking plate.

The meniscus is at the cornerstone of knee joint function, imparting stability and ensuring shock absorption, load transmission, and stress distribution within the knee joint. However, it is very vulnerable to injury and age-related degeneration. Meniscal tears are reported as the most common pathology of the knee with a mean annual incidence of 66 per 100,000. Knee osteoarthritis progresses more rapidly in the absence of a functional meniscus. Historically, tears extending to the avascular inner portion of the meniscus (white-white zone, “WW”), such as radial tears were considered as untreatable and were often resected, due to the lack of vascularity in the WW zone. Perfusion-based anatomical studies performed on cadaveric menisci in the 1980s shaped the current dogma that human meniscus has poor regenerative capacity, partly due to limited blood supply that only reaches 10 to 25% of the meniscus, commonly referred to as red-red zone (“RR”). Previous studies, including those utilizing animal models have shown mobilization of Mesenchymal Stem Cells (MSCs) upon injury into the WW zone, and successful MSC recruitment when administered externally to the injury site. We and others have recently reported positive outcomes of repaired tears in the inner zone of patients. We hypothesized that the “avascular” white-white zone of the meniscus possesses regenerative capacity due to a resident stem/progenitor cell population. Further, we sought to redefine the presence of microvessels in all meniscal zones using advanced stereology and imaging modalities.

Fifteen menisci from fresh human cadaveric knees (mean age: 21.53±6.53 years) without evidence of previous injury were obtained from two tissue banks (JRF, Centennial, CO) and Biosource Medical (Lakeland, FL) and utilized for this study. The use of cadaveric specimens for research purposes was approved by the institutional review board. Tibial plateaus were dissected to harvest medial and lateral menisci along their entire length. The RR, red-white (RW) and WW zones were dissected and separated into three thirds from the inner aspect to the marginal border of the meniscus and their wet weights recorded (Fig.1A). Meniscus tissue cellular content in each zone was obtained from dissociation of meniscus tissue using 0.02% w/v pronase (Millipore) for 1h at 37oC, followed by 18h 0.02% w/v collagenase II (Worthington) at 37oC with shaking. Isolated cells were characterized immediately after harvest using flow cytometry with antibodies against MSCs surface markers (CD105, CD90, CD44 and CD29) as well as respective isotype controls. Further, meniscal cells were cultured and split twice when confluence was reached, characterized at P2 and compared to bone marrow-derived MSCs (BM-MSCs) using the same markers. Self-renewal of cells was assessed using colony forming unit (CFU) assay. Differentiation assays were performed to assess whether colony-forming cells retained multilineage potential. For morphological examination of bigger vessels, samples were fixed in 10% formalin for 1 week, paraffin embedded, sectioned (4 μm thick) and stained with H&E and Masson's trichrome. Presence of microvessels was assessed by CD31 immunofluorescence staining. Further, menisci were cleared using the uDisco protocol labeled with the TO-PRO®-3 stain, a fluorescent dye that stains cell nuclei and imaged using light-sheet microscopy. All continuous data are presented as mean ±standard deviation. Non-repeated measures analysis of variance (ANOVA) and Tukey-Kramer HSD post hoc analysis were performed on sample means for continuous variables. Statistical significance was set at p < 0 .05.

Menisci were successfully cleared using a modified uDISCO procedure, imaged and analyzed for total cell density. As expected, bigger vessels were observed in RR but not in WW. However, immunofluorescent staining for CD31 showed a subset of CD31+endothelial cells present in the WW zone, indicating the presence of small vessels, most likely capillaries. In order to assess whether enzymatic digestion had a differential result depending on meniscus zone due to cellular content, we analyzed yields per meniscus per zone. The wet weight of different zones (WW:RW:RR) was at a ratio of ∼1:3:5 respectively, however, the ratio of cells isolated from each zone was at ∼1:4:20, indicating that RR has a denser population of mononuclear cells. However, the difference between all zones in cell yields was not significant. The clonogenic potential of isolated cells was shown to be non-significantly different between the three zones. Differentiation of isolated cells to osteogenic lineage using osteogenic media in vitroshowed no difference between the three zones. Flow cytometry analysis of cells from the three meniscal zones displayed presence of two distinct subpopulations of cells immediately after isolation. One subpopulation was positive to MSC surface markers and the other negative. Additionally, flow cytometry of cultured meniscal cells at P2 displayed that the entire cell population was CD44+CD105+CD29+CD90+, suggesting that culturing meniscal cells results in selection of stem/progenitor cells (plastic adherence). Surface marker expression analysis showed differential expression patterns between markers depending on zone. Similar fraction of cells was detected to express both MSC markers CD90 and CD105 (7–10%) and similar fraction of cells expressed both MSC markers CD29 and CD44 (1–2%) in all three zones, indicating similar density of resident stem/progenitor cells in each zone. Importantly, WW showed significantly higher expression for all four MSC markers compared to the RR zone, indicating higher relative density of stem/progenitor resident cells in the WW zone.

Our results determine that CD31-expressing microvessels were present in all zones, including the WW zone, which was previously considered completely avascular. Additionally, stem/progenitor cells were shown to be present in all three zones of the menisci, including the WW zone, showcasing its regenerative potential.

For any figures or tables, please contact the authors directly.

Purpose: To investigate the relationships between vascular endothelial growth factor (VEGF), a proliferation marker (Ki-67) and the cell cycle inhibitor p27 (cyclin-dependent kinase inhibitor p27), in endothelial cells in chronic degeneration of the rotator cuff.

Background: The rotator cuff is subject to constant pressure from the head of the humerus. This tends to ‘wring out’ the blood supply resulting in a functionally avascular critical zone, although microvessels can be identified. This zone is the site of degeneration and tears. Attempts at repair under these circumstances could be compromised by inadequate local function of the vascular system particularly sprouting of the capillaries to support the repair process.

Methods: Rotator cuff tissue was obtained from ten patients (age 40–80y) undergoing surgical repair. The size of tear was 1–4.5cm, time from presentation to surgery was 1 month (acute) to between 0.5–4y (chronic). Immunohistochemical staining with commercial mono-clonal antibodies to VEGF, p27, Ki-67 was performed on formalin fixed paraffin embedded tissues. Endothelial cells were identified by CD31 and smooth muscle actin (SMA) positivity. Visualisation used a standard DAB chromagen technique.

Results: Microvessel distribution varied according to tissue location, being pronounced towards the muscle insertion and torn edges of tissue, but much reduced in areas of healthy tendon and absent from areas with clear signs of advanced matrix degeneration without tears. Widespread VEGF positivity was observed in fibroblast and endothelial cell populations and diffusely within the matrix. Strong P27 positivity was observed in many endothelial cells which consequently demonstrated little Ki-67 staining.

Conclusion: Thus the endothelial cells appear to be simultaneously under both a mitogenic, VEGF drive, and subject to an inhibition of proliferation i.e. p27 positivity.

Objectives. To study the vascularity and bone metabolism of the femoral head/neck following hip resurfacing arthroplasty, and to use these results to compare the posterior and the trochanteric-flip approaches. Methods. In our previous work, we reported changes to intra-operative blood flow during hip resurfacing arthroplasty comparing two surgical approaches. In this study, we report the vascularity and the metabolic bone function in the proximal femur in these same patients at one year after the surgery. Vascularity and bone function was assessed using scintigraphic techniques. Of the 13 patients who agreed to take part, eight had their arthroplasty through a posterior approach and five through a trochanteric-flip approach. Results. One year after surgery, we found no difference in the vascularity (vascular phase) and metabolic bone function (delayed phase) at the junction of the femoral head/neck between the two groups of patients. Higher radiopharmaceutical uptake was found in the region of the greater trochanter in the trochanteric-flip group, related to the healing osteotomy. Conclusions. Our findings using scintigraphic techniques suggest that the greater intra-operative reduction in blood flow to the junction of the femoral head/neck, which is seen with the posterior approach compared with trochanteric flip, does not result in any difference in vascularity or metabolic bone function one year after surgery

Femoral neck fractures remain the leading cause of early failure after metal-on-metal hip resurfacing. Although its' exact pathomechanism has yet to be fully elucidated, current retrieval analysis has shown that either an osteonecrotic event and/or significant surgical trauma to the femoral head neck junction are the leading causes. It is most likely that no single factor like patient selection and/or femoral component orientation can fully avoid their occurrence. As in osteonecrosis of the native hip joint, a certain cell injury threshold may have to be reached in order for femoral neck fracture to occur. These insults are not limited to the surgical approach, but also include femoral head preparation, neck notching, and cement penetration.

Although some have argued that the posterior approach does not represent an increased risk fracture for ON after hip resurfacing because of the so-called intraosseous blood supply to the femoral head, to date, the current body of literature on femoral head blood flow in the presence of arthritis has confirmed the critical role of the extraosseous blood supply from the ascending branch of the medial circumflex, as well as the lack of any substantial intraosseous blood supply. Conversely, anterior hip dislocation of both the native hip joint as well as the arthritic hip preserves femoral head vascularity. The blood supply can be compromised by either sacrificing the main branch of the ascending medial femoral circumflex artery or damaging the retinacular vessels at the femoral head-neck junction. Thus an approach which preserves head vascularity, while minimizing soft tissue disruption would certainly be favorable for hip resurfacing. This presentation will review the current state of knowledge on vascularity of the femoral head as well as surgical techniques enhancing its preservation.

The evolution of bone plate design has been with a view to reducing the interface contact between the plate and the underlying bone thereby limiting the perfusion deþciency that developes. Little consequence however, has been attributed to the drilling of holes in the steps prior to bone plate application; the work present herein attempts to deþne the vascular response of bone to the trauma of drilling holes.

Anaesthetized sheep underwent the creation of drill holes in both tibiae and metatarsi. Animals were then heparinized and euthanatized. Utilizing femoral cannula, perfusion of the vasculature ensued; Spalteholz (India ink), Disulphine blue and radiocontrast material (Barium sulfate). Decalciþed histology was performed and correlated with the perfusion studies.

Regions of perfusion deþciency were observed immediately adjacent to, and removed from, the drill hole site. Radiographic images showed substantial haematoma formation and vascular disruption in the vicinity of the drill hole site. Histologically, blood vessels immediately adjacent and distal to the drill hole site, contained a proteinaceous/ cellular material occluding the vascular space.

Our þndings support the proposal of a short-term obstruction in cortical blood ßow which may contribute to later adaptational osteopaenia following bone plate application. We have observed an acute vascular insufþciency in cortical bone directly related to the trauma of drilling screw holes.

Purpose: The purpose of this study is to investigate the external and internal vascular anatomy of the lunate bone. The genesis of lunatomalacia requires some combination of load, vascular risk and mechanical predisposition. The findings will be correlated with the major existing theories of the cause of lunatomalacia and the most frequent fractures associated with Kienbocks disease: transverse shear fracture and midcoronal fracture.

Material and methods: We studied 21 cadaver upper limbs using latex injection and Spalteholz technique. We investigated the extra- and intraosseous blood supply. In 17 wrists we evaluate the incidence and distribution of anatomic features, arthrosis, and soft tissue lesions.

Results: The lunate morphology was 5 Type I (29.4%), 11 Type II (64.7%) and 1 Type III (5.9%). The lunate was found to have a separate facet for the hamate in 47.1% (Size 3–6 mm). Most frequent arthrosis was identified in the radius (88.2%) and lunate (94.1%). The triangular fibrocartilage complex (TFCC) was found torn in 47%, the lunotriquetral interosseous ligament (LTIL) was torn in 23.5%, and the scapholunate interosseous ligament (SLIL) was torn in 53% of the wrists. Statistical analysis found a correlation between the presence of arthrosis at the proximal pole of the hamate and the presence of a lunate facet. There was also a correlation between the presence of a tear in the SLIL and the presence of cartilage erosion in the scaphoid (p= 0.002). Arthrosis on the lunate was found to have a correlation with an SLIL tear or TFCC tear. The nutrient vessels entered the lunate throught the dorsal and volar poles in all the specimens. Dorsal vessels enter the bone through one or two foramina in the proximal, ulnar, and nonarticular aspect of the bone. Two to six nutrient vessels were observed entering the volar pole throught a ligament insertion: radioscapholunate ligament of Testut-Kuentz, radio-lunate-triquetrum ligament and ulnar-lunate-triquetrum ligament.

Conclusions: The lunate had consistent dorsal and palmar arteries entering the bone in all the specimens. The supply blood and foramina number is more important in the volar pole of the lunate than the dorsal pole. The vascular patterns support a theory of compression fracture from repeated trauma, or anatomical predispositions as the most likely cause of Kienbocks disease.

Fourteen hips with osteoarthritis had femoral head blood flow measured with laser Doppler flowmeter while undergoing during total hip replacement through a modified lateral approach. Mean age sixty-five years (48–77); eight males & six females. Two measurements were taken within the femoral head one after anterior hip dislocation and one after simulated notching of the femoral neck. All hips had a significant decrease in blood flow with a median percentage decrease of 76% (range 4.4–90.4). During surface arthroplasty of the hip, notching of the femoral neck may not only mechanically weaken the bone but also put the femoral head at risk of osteonecrosis.

To evaluate femoral head blood supply in patients with osteoarthrtis of the hip undergoing simulated notching of the femoral neck during total hip replacement and its potential implications in hip resurfacing.

During surface arthroplasty of the hip, notching of the femoral neck may not only mechanically weaken the femoral neck but also put the femoral head at risk of osteonecrosis and subsequent femoral loosening.

It would appear that the retinacular vessels (extraosseous blood supply) are as important in the arthritic femoral head as they are in the nonarthritic state, contradicting the notion that arthritic femoral heads in humans rely mainly on an intraosseous blood supply.

Fourteen hips with a diagnosis of degenerative arthritis had femoral head blood flow measured with laser Doppler flowmeter while undergoing during total hip replacement through a modified lateral approach. With the femoral head exposed and leg in neutral position, a 3.5mm drill hole was made into the anterior lateral quadrant and the fiber optic probe of the laser Doppler flowmeter (Moor Instruments, Wilmington Delaware, 20mW laser, wavelength 780nm) was inserted. Mean age was sixty-five years (48–77). Eight males and six females. Two measurements were taken one after anterior hip dislocation and one after simulated notching of the femoral neck. All but four hips had a significant decrease of more than 50% in blood flow after neck notching with a median percentage change of 76% (range 4.4–90.4), p< 0.001.

Introduction:

A surgical hip dislocation provides circumferential access to the femoral head and is essential in the treatment pediatric and adult hip disease. Iatrogenic injury to the femoral head blood supply during a surgical may result in the osteonecrosis of the femoral head. In order to reduce vessel injury and incidence of AVN, the Greater Trochanteric Osteotomy (GTO) was developed and popularized by Ganz. The downside of this approach is the increased morbidity associated with the GTO including non-union in 8% and painful hardware requiring removal in 20% of patients. (reference) Recent studies performed at our institution have mapped the extra-osseous course of the medial femoral circumflex artery and provide surgical guidelines for a vessel preserving posterolateral approach. In this cadaveric model using Gadolinium enhanced MRI, we investigate whether standardized alterations in the postero-lateral surgical approach may reliably preserve femoral head vascularity during a posterior surgical hip dislocation

We investigated the blood flow to the femoral head during and after Resurfacing Arthroplasty of the hip.

In a previous study, we recorded the intra-operative blood flow in 12 patients who had a posterior approach to the hip and 12 who had a trochanteric flip approach. Using a LASER Doppler flowmeter, we found a 40% drop in blood flow in the posterior group and an 11% drop in the trochanteric flip group (p<0.001). The aim of this current study was to find out whether the intra-operative fall in blood flow persists during the post-operative period.

We therefore conducted a Single Positron Emission Tomography (SPECT) scan on 14 of the same group of patients. The proximal femur was divided into four regions of interest. These were the mid-shaft, proximal shaft, inter-trochanteric and head-neck regions. The data was analysed for bone activity and comparisons made between the two groups for each region of the femur. We found that the bone activity in the mid-shaft, upper-shaft, and head-neck regions was the same eleven months after the surgery irrespective of the approach to the hip. However there was higher activity in the trochanteric flip group in the inter-trochanteric region.

We conclude that the intra-operative deficit in blood flow to the head-neck region of the hip associated with the posterior approach does not seem to persist in the late post-operative period. We believe the reason for increased bone activity in inter-trochanteric region to be due to the healing of the trochanteric flip osteotomy.

Objectives

Metal-on-metal hip resurfacing (MOMHR) is available as an alternative option for younger, more active patients. There are failure modes that are unique to MOMHR, which include loosening of the femoral head and fractures of the femoral neck. Previous studies have speculated that changes in the vascularity of the femoral head may contribute to these failure modes. This study compares the survivorship between the standard posterior approach (SPA) and modified posterior approach (MPA) in MOMHR.

Introduction. In the setting of periprosthetic joint infection, the complete removal of implants and cement can be challenging with well-fixed, cemented implants about the knee. This can get especially complex in the setting of long cemented femoral stems. Osteotomies are well described in the proximal femur and tibia for removal of implants and cement. There is little information available on distal femoral osteotomies to facilitate knee implant and retained cement removal. Methods. We describe a novel anterolateral oblique distal femoral osteotomy for the removal of well-fixed, cemented components during resection knee arthroplasty that preserves vascularity to the osteotomized segment. Cadaveric anatomic vascular injection studies were performed to document vascularity of the osteotomized segment. Clinical examples, and results will be presented. Results. Anatomic vascular studies documented preserved vascularity to the osteotomized segment. In two patients intramedullary infected implant and cement was completely removed. At reimplantation and final followup the osteotomy was radiographically healed, implants well fixed, and no recurrent infections were noted. Conclusions. This osteotomy appears to be useful when removing well fixed, cemented femoral components during periprosthetic infection. Vascularity and union was preserved and obtained in all patients. For figures, tables, or references, please contact authors directly

Incidence of Congenital talipes equino varus [CTEV] is 1 to 2 per 1000 birth, Out of all cases 20% cases are Non-idiopathic. The management of non-idiopathic CTEV, however, continues to be challenging due to Rigidity, Poor skin condition, Bony changes, Vascularity and Associated congenital abnormalities. In recent literature, short term results of Ponseti method for correction of non-idiopathic CTEV have been encouraging. As Ponseti method decreases the severity of deformity and hence decreases the need for extensive surgery. The aim of current study is to evaluate the results of Ponseti method in Non-idiopathic CTEV. Total 7 children below the age of one year with Non idiopathic clubfoot presented to us in the duration of 2013 to 2015 who were treated by us. The cases included are Streeters Dysplasia with congenital constriction rings 3, Arthrogryposis multiplex congenita with Developmental dysplasia of hip 2, Arthrogryposis multiple congenita spina Bifida 1, Pierre Robinson Syndrome with Ichthiosis 1. Initially all the patients treated with Ponseti casting technique and scoring was done using modified pirani scoring. At an average we could correct the foot from Pirani 7 to 2.5 with a relapse in 4 patients. 2 patients were treated again by Ponseti's method with success while treatment was discontinued in 2 feet. We recommended Ponseti's technique in Syndromic clubfoot as an non-surgical initial modality with good results given. The final outcome may depend more on the underlying condition than the CTEV

Aims

A revision for periprosthetic joint infection (PJI) in total hip arthroplasty (THA) has a major effect on the patient’s quality of life, including walking capacity. The objective of this case control study was to investigate the histological and ultrastructural changes to the gluteus medius tendon (GMED) in patients revised due to a PJI, and to compare it with revision THAs without infection performed using the same lateral approach.

Introduction. We present a single surgeon series of 20 modified Dunn osteotomies without surgical dislocation of the femoral head for slipped upper femoral epiphysis (SUFE). Method. All patients from 2007 to 2011 who had a Dunn osteotomy for SUFE had their notes reviewed and we obtained an updated Non Arthritic Hip Score. Results. 20 patients were identified, of which 5 were female, with a combined average age of 14. The average duration of symptoms prior to the procedure was 10.2 weeks (range, 4–78). Classifications divided the cases into 7 chronic slips, 7 acute-on-chronic, and 5 acute., and 7 of the cases were unstable slips with an average slip angle of 71 degrees (range 65–85). All slips were grade 3. Average follow up was 26.2 months (range, 2–62). 3 developed avasular necrosis (2 unstable, 1 stable) and 2 patients had symptomatic leg length discrepancy. Preoperative MRI scans were performed in 4 patients and showed vascular compromise, but this did not always correlate with intraoperative findings of avascularity when the head was drilled. The average Nonarthritic hip score was 71.6 (range, 60–80). Summary. Dunn osteotomies are safe in patients with chronic slips, and have a low incidence of AVN. Overall function was good, even in those patients with segmental AVN scoring highly on their hip scores. Keeping the ligamentum teres intact and not dislocating the femoral head may improve vascularity of the head. Vascularity may also be assessed by preoperative MRI scans, although radiological suggestion of an avascular head which contradicted clinical findings and postoperative outcome may be due to transient vessel spasm

Aims

The localization of necrotic areas has been reported to impact the prognosis and treatment strategy for osteonecrosis of the femoral head (ONFH). Anteroposterior localization of the necrotic area after a femoral neck fracture (FNF) has not been properly investigated. We hypothesize that the change of the weight loading direction on the femoral head due to residual posterior tilt caused by malunited FNF may affect the location of ONFH. We investigate the relationship between the posterior tilt angle (PTA) and anteroposterior localization of osteonecrosis using lateral hip radiographs.

Skin necrosis after total knee arthroplasty can rapidly lead to infection of the prosthetic components. Risk factors for the development of skin necrosis include rheumatoid arthritis, steroid use, immunosuppression, malnutrition, peripheral vascular disease, and multiple prior scars. Vascularity of the skin over the knee will affect the rate of healing postoperatively and risk of necrosis. Johnson measured transcutaneous skin oxygen tension and found that the oxygen tension decreases for the first two to three days after surgery and then increases. In addition, the lateral skin edge is more hypoxic than the medial edge. This suggests that when multiple prior scars are present, the most vertical lateral incision should be used to minimise skin hypoxia. Constant passive motion further decreases skin oxygen tension. Particularly for patients with multiple risk factors for developing wound complications, avoidance or delayed used of early range of motion exercises may be beneficial in reducing the development of skin necrosis. If skin necrosis does occur after total knee arthroplasty, early recognition of the problem and treatment will minimise the risk of deep infection of the prosthetic components. Necrosis of the proximal wound including the area over the patella may be treated by local wound care and skin grafting. However, necrosis over the tibial tubercle or patellar tendon requires muscle flap coverage to prevent infection involving the patellar tendon. If the patellar tendon is not viable and the extensor mechanism disrupted, the medial gastrocnemius flap can also be used to augment the extensor mechanism. The tendon of the gastrocnemius is repaired to the quadriceps tendon maintaining continuity between the tibia and extensor mechanism

Shoulder Arthroscopy techniques may pose surgical risk to vascular structures that may cause active bleeding during surgery. The vascularity of the subacromial structures showed constant patterns of distribution and specific sources of bleeding were analyzed. Knowledge of the vascular anatomy may decrease the bleeding during subacromial arthroscopy surgery. Shoulder Arthroscopy techniques may pose surgical risk to vascular structures that may cause active bleeding during surgery. A detailed anatomy map of frequent sources of bleeding is more than desired in order to properly identify these bleeding points, and avoid the unnecessary overuse of thermal tools and pressure pumps to control the hemorrhage. Our purpose is to study the vascular anatomy of the subacromial space, and to map the major sources of expected bleeding during subacromial arthroscopy surgery. Ten shoulders of five adult cadavers underwent whole body arterial perfusion with a mixture of lead oxide, gelatin and water. The shoulders were dissected, photographed, tissue specimens were radio graphed, scanned and analyzed with a digital software analyzer. Careful dissection of the different arteries of the subacromial bursa, and anatomic landmarks of the walls were documented. Correlations of bleeding areas during subacromial arthroscopic surgery and cadaver dissection were carried out. A vascular map of the bursa was created. The vascularity of the subacromial structures showed constant patterns of distribution and specific sources of bleeding were analyzed. We divided this space into walls with their major arteries as follows: Anterior wall: Acromial branch of the thoracoacromial artery. Posterior wall: Acromial branch of the suprascapular artery. Medial wall: Anterior and posterior Arteries of the AC joint. Lateral wall: No major arteries identified. Vascularity of the roof and floor is also described. The subacromial space is highly vascular. Knowledge of the vascular anatomy may decrease the bleeding during subacromial arthroscopy surgery

Aims

Mechanical stimulation is a key factor in the development and healing of tendon-bone insertion. Treadmill training is an important rehabilitation treatment. This study aims to investigate the benefits of treadmill training initiated on postoperative day 7 for tendon-bone insertion healing.