Purpose. Addressing posterior tibial plateau fractures is increasingly recognized as an important prognostic factor for functional outcome. The treatment of posterior tibial plateau fractures is rather demanding and the implants are still standard, off-the-shelf implants. This emphasizes the need for a more thorough morphological study of the posterior tibial plateau, in order to treat these posterior fractures more adequately. We aimed to demonstrate anatomical variations of the tibia in order to develop better implants. Method. After approval of the ethical committee 22 historically available CT scans of intact left tibia”s were segmented using Mimics (Materialise, Belgium). In order to perform principal component analysis, corresponding meshes are necessary. Mesh correspondence was achieved by deforming one selected source tibia to every other target tibia, through non rigid registration. The non-rigid registration algorithm was based on the algorithm described by Amberg et al (ref). After performing the non-rigid registration, principal component analysis was performed in Matlab (Mathworks, USA). Results. The first 3 components account for 98,1% of the anatomical shape variation of the tibia. The first principal component accounts for 95,4, the second accounts for 1,6% and the third component accounts for the remaining 1,1% of variation. In the first principal component the most marked variation was the length and the shaft width. Shorter tibia”s have a steeper and more angled posterior medial and lateral plateau as where longer tibia”s have a more rounded posterior tibia plateau. On the distal end, the tip of the medial malleolus is more prominent in shorter tibia”s than in longer tibia”s. The orientation of the tibiofibular joint is directed more posteriorly in larger tibias where it is orientated more laterally in smaller tibia”s. The slope of the medial and lateral tibia plateau is not related to the length or width of the plateau. The second principal component shows a relationship between a valgus shaped tibia shaft and its relation to a relatively smaller medial plateau”s compared with straight tibia”s of the same length. Valgus shaped, small tibia shafts have more posteriorly tilted lateral plateau”s compared with straight, broad shafted tibias. The third principal component shows that an angular shaped posterior tibia plateau is related to a more increased anterior bowing. The increase in the posterior tilt is mostly marked in the medial tibia plateau. Conclusion. The majority of tibia shape variations is directly related to the length of the shaft. The clinically known varus and valgus deformations represent only a small percentage of the total variation. Nevertheless, their variation within the second component is large and has a direct relation to the morphology of the tibia plateau. This data coud furthermore be used to improve implant design

Artificial bone models (ABMs) are commonly used in traumatology and orthopedics for training, education, research and development purposes. The aim of this study was to develop the first evidence-based generic Asian pelvic bone model and compare it to an existing pelvic model. A hundred clinical CT scans of intact adult pelvises (54.8±16.4 years, 161.3±8.3 cm) were acquired. They represented evenly distributed female and male patients of Malay (n=33), Chinese (n=34) and Indian (n=33) descent. The CTs were segmented and defined landmarks were placed. By this means, 100 individual three-dimensional models were calculated using thin plate spline transformation. Following, three statistical mean pelvic models (male, female, unisex) were generated. Anatomical variations were analyzed using principal component analysis (PCA). To quantify length variations, the distances between the anterior superior iliac spines (ASIS), the anterior inferior iliac spines (AIIS), the promontory and symphysis (conjugate vera) as well as the ischial spines (diameter transversa) were measured for the three mean models and the existing ABM. PCA demonstrated large variability regarding pelvic surface and size. Principal component one (PC 1) contributed to 24% of the total anatomical variation and predominantly displayed a size variation pattern. PC 2 (17.7% of variation) mainly exhibited anatomical variations originating from differences in shape. Female and male models were similar in ASIS (225±20 mm; 227±13 mm) and AIIS (185±11 mm; 187±10 mm), whereas differed in conjugate vera (116±10 mm; 105±10 mm) and diameter transversa (105±7 mm; 88±8 mm). Comparing the Asian unisex model to the existing ABM, the external pelvic measurements ASIS (22.6 cm; 27.5 cm) and AIIS (186 mm; 209 mm) differed notably. Conjugate vera (111 mm; 105 mm) and diameter transversa (97 mm; 95 mm) were similar in both models. Low variability of mean distances (3.78±1.7 mm) was found beyond a sample number of 30 CTs. Our analysis revealed notable anatomical variations regarding size dominating over shape and gender-specific variability. Dimensions of the generated mean models were comparatively smaller compared to the existing ABM. This highlights the necessity for generation of Asian ABMs by evidence-based modeling techniques

Variations in pelvic anatomy are a major risk factor for misplaced percutaneous sacroiliac screws used to treat unstable posterior pelvic ring injuries. A better understanding of pelvic morphology improves preoperative planning and therefore minimises the risk of malpositioned screws, neurological or vascular injuries, failed fixation or malreduction. Hence a classification system which identifies the clinically important anatomical variations of the sacrum would improve communication among pelvic surgeons and inform treatment strategy. 300 Pelvic CT scans from skeletally mature trauma patients that did not have pre-existing posterior pelvic pathology were identified. Axial and coronal transosseous corridor widths at both S1 and S2 were recorded. Additionally, the S1 lateral mass angle were also calculated. Pelvises were classified based upon the sacroiliac joint (SIJ) height using the midpoint of the anterior cortex of L5 as a reference point. Four distinct types could be identified:. Type-A – SIJ height is above the midpoint of the anterior cortex of the L5 vertebra. Type-B – SIJ height is between the midpoint and the lowest point of the anterior cortex of the L5 vertebra. Type-C – SIJ height is below the lowest point of the anterior cortex of the L5 vertebra. Type-D – a subgroup for those with a lumbosacral transitional vertebra, in particular a sacralised L5. Differences in transosseous corridor widths and lateral mass angles between classification types were assessed using two-way ANOVAs. Type-B was the most common pelvic type followed by Type-A, Type-C, and Type-D. Significant differences in the axial and coronal corridors was observed for all pelvic types at each level. Lateral mass angles increased from Types-A to C, but were smaller in Type-D. This classification system offers a guide to surgeons navigating variable pelvic anatomy and understanding how it is associated with the differences in transosseous sacral corridors. It can assist surgeons’ preoperative planning of screw position, choice of fixation or the need for technological assistance

Abstract. Objectives. Ultrasound speckle tracking is a safe and non-invasive diagnostic tool to measure soft tissue deformation and strain. In orthopaedics, it could have broad application to measure how injury or surgery affects muscle, tendon or ligament biomechanics. However, its application requires custom tuning of the speckle-tracking algorithm then validation against gold-standard reference data. Implementing an experiment to acquire these data takes months and is expensive, and therefore prohibits use for new applications. Here, we present an alternative optimisation approach that automatically finds suitable machine and algorithmic settings without requiring gold-standard reference data. Methods. The optimisation routine consisted of two steps. First, convergence of the displacement field was tested to exclude the settings that would not track the underlying tissue motion (e.g. frame rates that were too low). Second, repeatability was maximised through a surrogate optimisation scheme. All settings that could influence the strain calculation were included, ranging from acquisition settings to post-processing smoothing and filtering settings, totalling >1,000,000 combinations of settings. The optimisation criterion minimised the normalised standard deviation between strain maps of repeat measures. The optimisation approach was validated for the medial collateral ligament (MCL) with quasi-static testing on porcine joints (n=3), and dynamic testing on a cadaveric human knee (n=1, female, aged 49). Porcine joints were fully dissected except for the MCL and loaded in a material-testing machine (0 to 3% strain at 0.2 Hz), which was captured using both ultrasound (>14 repeats per specimen) and optical digital image correlation (DIC). For the human cadaveric knee (undissected), 3 repeat ultrasound acquisitions were taken at 18 different anterior/posterior positions over the MCL while the knee was extended/flexed between 0° and 90° in a knee extension rig. Simultaneous optical tracking recorded the position of the ultrasound transducer, knee kinematics and the MCL attachments (which were digitised under direct visualisation post testing). Half of the data collected was used for optimisation of the speckle tracking algorithms for the porcine and human MCLs separately, with the remaining unseen data used as a validation test set. Results. For the porcine MCLs, ultrasound strains closely matched DIC strains (R. 2. > 0.98, RMSE < 0.59%) (Figure 1A). For the human MCL (Figure 1B), ultrasound strains matched the strains estimated from the optically tracked displacements of the MCL attachments. Furthermore, strains developed during flexion were highly correlated with AP position (R = 0.94) with strains decreasing the further posterior the transducer was on the ligament. This is in line with previously reported length change values for the posterior, intermediate and anterior bundles of the MCL. Conclusions. Ultrasound speckle tracking algorithms can be adapted for new applications without ground-truth data by using an optimisation approach that verifies displacement field convergence then minimises variance between repeat measurements. This optimisation routine was insensitive to anatomical variation and loading conditions, working for both porcine and human MCLs, and for quasi-static and dynamic loading. This will facilitate research into changes in musculoskeletal tissue motion due to abnormalities or pathologies. Declaration of Interest. (a) fully declare any financial or other potential conflict of interest

The purpose of this anatomical study was to explore the morphological variations of the semitendinosus and gracilis tendons in length and cross-section and the statistical relationship between length, cross-section, and body height. We studied the legs of 93 humans in 136 cadavers. In 43 specimens (46.2%) it was possible to harvest the tendons from both legs. We found considerable differences in the length and cross-section of the semitendinosus and the gracilis tendons with a significant correlation between the two. A correlation between the length of the femur, reflecting height, and the length of the tendons was only observed in specimens harvested from women. The reason for this gender difference was unclear. Additionally, there was a correlation between the cross-sectional area of the tendons and the length of the femur. Surgeons should be aware of the possibility of encountering insufficient length of tendon when undertaking reconstructive surgery as a result of anatomical variations between patients

The morphology of the proximal part of the humerus varies largely. Morphometric features characterizing the three-dimensional geometry of the proximal humerus have revealed a wide difference within individuals. These parameters include head size, radius of curvature, inclination angle, retroversion angle, offsets and neck-shaft angle. Different implant designs have been adapted so as to make provision for these anatomical variations. However, the optimal design criteria are yet to be established. Implant design is one of the main factors determining the success of Total Shoulder Arthroplasty (TSA) since slight modifications in the implant anatomy could have significant biomechanical effects. Therefore, this study investigates the three-dimensional morphometric parameters of the South African proximal humerus which will serve as a basis for designing a new Total Shoulder Prosthesis for the South African population. Sixteen South African (SA) fresh cadaveric humeri (8 left, 8 right; 8 paired) were used in this study. The data consisted of 6 men and 2 women with ages ranging from 32 to 55 years (43.13 ±8.51). The humeri were scanned using a Computer Tomography (CT) scanner. The Digital Imaging and Communications in Medicine (DICOM) files from the CT data were imported into medical modelling software, MIMICS for reconstruction. The 3D reconstructed model of the humeri as an STL file was used for further processing. The STL data were generated as a cloud of points in a CAD software, SolidWorks. These were then remodeled by defining the detailed Referential Geometric Entities (RGEs) describing the anatomical characteristics. Anatomical reference points were defined for the anatomical neck plane, the epiphyseal sphere and the metaphyseal cylinder. Also, axes were defined which comprises of the humeral head axis and the metaphyseal axis. Thereafter, the posterior offsets medial offsets and the inclination angles were measured based on the RGEs. The posterior offset varied from 0.07 mm to 2.87 mm (mean 1.20 mm), the medial offset varied from 4.40 mm to 8.45 mm (mean 6.50 mm) while the inclination angle varied from 114.00º to 133.87º (mean 121.05º). The outcome of the study showed that the shape and dimensions of the proximal humerus varies distinctively. The articular surface is not a perfect sphere and differs independently with respect to the inclination angles. In addition, variations were noticeable in the medial and lateral offsets. The morphometric data on the African shoulder is very limited and this study will significantly contribute to the shoulder data repository for the SA population. The morphometric parameters measured in this study will be useful in designing a South African shoulder prosthesis that mimics the native shoulder hence eliminating post-surgical complications

Summary. Anatomical variations in hip joint anatomy are associated with both the presence and location of tibiofemoral osteoarthritis (OA). Introduction. Variations in hip joint anatomy can alter the moment-generating capacity of the hip abductor muscles, possibly leading to changes in the magnitude and direction of ground reaction force and altered loading at the knee. Through analysis of full-limb anteroposterior radiographs, this study explored the hypothesis that knees with lateral and medial knee OA demonstrate hip geometry that differs from that of control knees without OA. Patients and Methods. This cross-sectional study is an ancillary to the Multicenter Osteoarthritis Study (MOST), an observational cohort study of incident and progressive knee OA in community-dwelling men and women, ages 50–79 years. We report on 160 knees with lateral OA (LOA), 168 knees with medial OA (MOA), and 336 controls. All participants with LOA at the baseline MOST visit were included. An equal number of knees with MOA, and twice the number of control knees were then randomly selected. In participants with bilateral eligibility, a single knee was randomly selected so that all participants contributed only one case or one control knee to the analysis. Case knees were identified as having Kellgren/Lawrence (K/L) ≥ 2 with joint space narrowing (JSN) ≥ 1 in the specified compartment with no JSN in the adjoining compartment. Controls had no radiographic OA (K/L=0 or 1 and JSN=0) in either compartment. Hip joint anatomy parameters were assessed from full-limb standing radiographs using custom OsiriX software by an author (AB) blinded to knee OA status, and unreadable radiographs (N = 8) were discarded prior to unblinding. We measured parameters that influence the abductor moment arm of the hip, including: abductor lever arm, femoral offset, femoral neck length, femoral neck-shaft angle, height of hip centre, body weight lever arm, acetabular version, and abductor angle. All hip measurements were taken from the ipsilateral side of the knee in interest. Each variable was then compared independently among the three groups via analysis of covariance (ANCOVA), controlling for age, sex, and body mass index (BMI), and followed up with a post-hoc Bonferroni analysis to distinguish pairwise group differences. Results. The ANCOVA analysis showed a significant difference in height of hip centre (p=0.001), femoral neck-shaft angle (p=0.009), and abductor angle (p=0.001). Compared to controls, knees with LOA had an increased height of hip centre (p=0.001) and knees with MOA had a decreased abductor angle (p=0.046). Compared to knees with MOA, those with LOA had a more valgus neck-shaft angle (p=0.007) and increased abductor angle (p=0.001). Conclusion. Our study demonstrates that variations in hip geometry that affect the moment-generating capacity of the hip abductors are associated with the presence and compartmental distribution of tibiofemoral OA in the ipsilateral knee. Anatomical arrangements that reduce the hip abductor moment arm are more strongly associated with LOA than with MOA

The meniscofemoral ligaments (MFL) of the knee have both functional and clinical importance, but have been poorly described. We examined 42 human cadaver knees: there was at least one MFL in every joint and both ligaments were present in 27. The anterior MFL was present in the knees in all 18 males and in 17 of the 24 females. The posterior MFL was present in 16 males and 22 females. Measurement of the ligaments showed that they were of significant size. The mean midpoint width for the anterior MFL was 5.09 ± 1.41 mm in males and 2.99 ± 1.29 mm in females. The mean width of the posterior MFL was 5.48 ± 2.13 mm in males and 3.79 ± 2.56 mm in females. The average length of the anterior MFL was 27.09 ± 2.15 mm in males and 24.38 ± 3.39 mm in females, and the posterior MFL was 31.13 ± 2.54 mm and 27.59 ± 3.74 mm, respectively. There were anatomical variations in 16 (38%) knees (62.5% female, 37.5% male), more commonly in the posterior ligament. We conclude that the meniscofemoral ligaments are anatomically and probably functionally important structures in the human knee

Objectives

Acetabular retractors have been implicated in damage to the femoral and obturator nerves during total hip replacement. The aim of this study was to determine the anatomical relationship between retractor placement and these nerves.

In order to determine the potential for an internervous safe zone, 20 hips from human cadavers were dissected to map out the precise pattern of innervation of the hip capsule. The results were illustrated in the form of a clock face. The reference point for measurement was the inferior acetabular notch, representing six o’clock. Capsular branches from between five and seven nerves contributed to each hip joint, and were found to innervate the capsule in a relatively constant pattern. An internervous safe zone was identified anterosuperiorly in an arc of 45° between the positions of one o’clock and half past two.

Our study shows that there is an internervous zone that could be safely used in a capsule-retaining anterior, anterolateral or lateral approach to the hip, or during portal placement in hip arthroscopy.

Anatomical descriptions of the lateral retinaculum have been published, but the attachments, name or even existence of its tissue bands and layers are ill-defined. We have examined 35 specimens of the knee. The deep fascia is the most superficial layer and the joint capsule is the deepest. The intermediate layer is the most substantial and consists of derivatives of the iliotibial band and the quadriceps aponeurosis. The longitudinal fibres of the iliotibial band merge with those of the quadriceps aponeurosis adjacent to the patella. These longitudinal fibres are reinforced by superficial arciform fibres and on the deep aspect by transverse fibres of the iliotibial band. The latter are dense and provide attachment of the iliotibial band to the patella and the tendon of vastus lateralis obliquus.

Our study identifies two important new findings which are a constant connection of the deep fascia to the quadriceps tendon superior and lateral to the patella, and, a connection of the deeper transverse fibres to the tendon of vastus lateralis obliquus.

We have evaluated the effect of the short-term administration of low therapeutic doses of modern COX-2 inhibitors on the healing of fractures.

A total of 40 adult male New Zealand rabbits were divided into five groups. A mid-diaphyseal osteotomy of the right ulna was performed and either normal saline, prednisolone, indometacin, meloxicam or rofecoxib was administered for five days. Radiological, biomechanical and histomorphometric evaluation was performed at six weeks.

In the group in which the highly selective anti-COX-2 agent, rofecoxib, was used the incidence of radiologically-incomplete union was similar to that in the control group. All the biomechanical parameters were statistically significantly lower in both the prednisolone and indometacin (p = 0.01) and in the meloxicam (p = 0.04) groups compared with the control group. Only the fracture load values were found to be statistically significantly lower (p = 0.05) in the rofecoxib group. Histomorphometric parameters were adversely affected in all groups with the specimens of the rofecoxib group showing the least negative effect.

Our findings indicated that the short-term administration of low therapeutic doses of a highly selective COX-2 inhibitor had a minor negative effect on bone healing.

We used a canine intercalary bone defect model to determine the effects of recombinant human osteogenic protein 1 (rhOP-1) on allograft incorporation. The allograft was treated with an implant made up of rhOP-1 and type I collagen or with type I collagen alone.

Radiographic analysis showed an increased volume of periosteal callus in both test groups compared with the control group at weeks 4, 6, 8 and 10. Mechanical testing after 12 weeks revealed increased maximal torque and stiffness in the rhOP-1 treated groups compared with the control group.

These results indicate a benefit from the use of an rhOP-1 implant in the healing of bone allografts. The effect was independent of the position of the implant. There may be a beneficial clinical application for this treatment.