Anatomic Center Research Articles

Biomechanical Analysis of Range of Motion and Failure Characteristics of Osteoporotic Spinal Compression Fractures in Human Cadaver.

Background:Vertebroplasty is a treatment for osteoporotic vertebral compression fractures. The optimal location of needle placement for cement injection remains a topic of debate. As such, the authors assessed the effects of location of two types of cement instillations. In addition, the motion and failure modes at the index and adjacent segments were measured.Materials and Methods:Seven human osteoporotic cadaver spines (T1-L4), cut into four consecutive vertebral segments, were utilized. Of these, following the exclusion of four specimens not suitable to utilize for analysis, a total of 24 specimens were evaluable. Segments were randomly assigned into four treatment groups: unipedicular and bipedicular injections into the superior quartile or the anatomic center of the vertebra using confidence (Confidence Spinal Cement System®, DePuy Spine, Raynham, MA, USA) or polymethyl methacrylate. The specimens were subjected to nondestructive pure moments of 5 Nm, in 2.5 Nm increments, using pulleys and weights to simulate six degrees of physiological motion. A follower preload of 200 N was applied in flexion extension. Testing sequence: range of motion (ROM) of intact specimen, fracture creation, cement injection, ROM after cement, and compression testing until failure. Nonconstrained motion was measured at the index and adjacent levels.Results:At the index level, no significant differences were observed in ROM in all treatment groups (P > 0.05). There was a significant increase in adjacent level motion only for the treatment group that received a unipedicular cement injection at the anatomic center.Conclusion:The location of the needle (superior or central) and treatment type (unipedicular or bipedicular) had no significant effect on the ROM at the index site. At the adjacent levels, a significant increase occurred with therapy through a unipedicular approach into the centrum of the vertebra at the treated segment.

Intraoperative Mulitplanar Alignment System to Guide Triplanar Correction of Hallux Valgus Deformity

Hallux valgus surgery or “bunion surgery” is one of the most common surgical procedures for the foot and ankle surgeon. As we continue to gain understanding of this complex deformity, it has become clear that our understanding may be incomplete. The Lapidus procedure was described over 80 years ago and still offers many challenges. Often the choice of a Lapidus procedure is not considered due to the complexity or perceived complications. As the traditional Lapidus procedure relied on multiple freehand steps that can be fraught with error, it was often relegated to be used as a last resort. As our understanding of the hallux valgus deformity has grown it is becoming clear that the anatomic Center of Rotation of Angulation of the deformity may lie at the tarsometatarsal joint. There is also the component of the 3-dimensional nature of the deformity that may be best addressed at this anatomic Center of Rotation of Angulation. With those issues in mind, it was necessary to address the shortcomings of the traditional Lapidus procedure and progress toward more consistent, instrumented steps that could address the 3-dimensional nature of the deformity. Level of Evidence: Level IV—Technique presentation.

Proper Distal Placement of Tibial Nail Improves Rate of Malalignment for Distal Tibia Fractures

We hypothesize that the anatomic center of the distal tibia is just lateral and anterior to the center of the distal tibia articular surface in the coronal and sagittal planes, respectively, and that placement of the nail along this axis results in improved rates of malalignment when treating distal tibia fractures. Retrospective study. Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence. One Level I and one Level II trauma center. Two hundred three distal tibia fractures treated with intramedullary nailing (IMN) (primary cohort) whose main fracture line extended within 5 cm of the plafond to evaluate the rate of malalignment with distal nail placement. Additionally, we retrospectively reviewed a secondary cohort of 15 patients with proximal tibia fractures treated with intramedullary nailing for evaluation of passive anatomic distal nail position. Primary malalignment ≤5 degrees on the anteroposterior (AP), mortise, and lateral planes were evaluated in distal tibia fractures on perioperative radiographs. Primary Cohort: 85 patients met inclusion criteria for evaluation in the coronal plane. Overall malalignment in the coronal plane was 17.6%. There was a 2.9% (1/34) fracture malalignment rate when the nail was placed lateral to the center of the joint versus 27.5% (14/51) when placed medial to the center of the joint, with all occurring in valgus. This achieved statistical significance (P = 0.04). Correlation was highest when measuring the trajectory on mortise view using the talus as reference point. When evaluating the sagittal plane, there were 64 patients that met inclusion criteria with a 48% malalignment rate. Malalignment was greatest when the nail was placed in the anterior quadrant 100% (4/4), versus 50% (22/44) in the anterior middle, and 31.3% (5/16) in the posterior middle quadrant. This achieved statistical significance (P = 0.05). No nails were placed in the most posterior quadrant. Secondary Cohort: 15 patients met inclusion criteria for distal nail placement. The position of the nail in the coronal plane was measured on both the anteroposterior and mortise ankle radiographs using both the plafond and talus as a reference, whereas sagittal nail placement was measured on the lateral ankle radiographs. In the coronal plane, the mean passive distal position of the nail when referenced from the lateral cortex was 45.2% of the tibia plafond and 45.5% the width of the talus, or just lateral to the center of each. In the sagittal plane, passive nail placement was 40% the sagittal width of the joint measured from the anterior cortex, or just anterior to the center of the joint. This is the first patient series that defines optimal tibial nail placement in the treatment of distal tibia fractures. Distal placement of the nail just lateral to the center of the talus and plafond, or along mechanical axis of the tibia, results in significantly reduced rates of malalignment on the coronal plane when compared to nail placement medial to the center of the talus or plafond. Fluoroscopic judgment of distal nail trajectory was improved on the mortise view using the talus as a reference when compared to using the anteroposterior view. On the sagittal plane, anatomic passive nail placement is just anterior to the center of the plafond. However, nonanatomic nail placement just posterior to the center of the plafond had a lower incidence of malalignment compared with nails placed anterior to the center of the plafond. Further study of appropriate nail positioning on the sagittal plane is needed.

Subtrochanteric shortening osteotomy during cementless total hip arthroplasty in young patients with severe developmental dysplasia of the hip

BackgroundThis retrospective study was designed to determine complications, functional and radiographic results of transverse subtrochanteric osteotomy during cementless, modular total hip arthroplasty (THA) in a series of active patients younger than 45 years with Crowe Type-III or IV developmental dysplasia of the hip (DDH).MethodsWe followed 49 patients (56 hips) with DDH who were treated with cementless THA, where the acetabular cup was positioned in the anatomic hip center and where a simultaneous transverse femoral osteotomy was performed. Complication rate evaluation and clinical outcomes were measured by validated clinical scores and radiographic evaluation were performed at a mean follow up of 10 years (range, 4.8–14.3 years).ResultsThe mean limb-length discrepancy was reduced from 4.2 cm to 1.1 cm (P < 0.01). The mean Harris hip score (HSS) significantly improved from 40.6 points to 87.4 points (P < 0.01). Similarly, severity of low back pain, modified MAP, HOOS, and SF-12 also showed significant improvement (P < 0.01). There were 3 cases of postoperative dislocation, 3 cases of transient nerve palsy, 2 cases of nonunion, and 4 cases of intraoperative fracture. At 10 years follow-up, the estimated survival rate with any component revision as end points was 92%.ConclusionThe cementless THA combined with transverse subtrochanteric osteotomy is a reliable technique with restoration of a more normal limb, satisfactory clinical outcomes, and mid-term survival of components.

A new aiming guide can create the tibial tunnel at a favorable position in transtibial pullout repair for the medial meniscus posterior root tear

An anatomical placement of the medial meniscus posterior root (MMPR) attachment is considered to be critical in transtibial pullout repair of the MMPR tear. However, tibial tunnel creation at the anatomical attachment of the MMPR is technically difficult using a conventional aiming deviee. The aim of this study was to compare two aiming guides. We hypothesized that a newly-developed guide creates the tibial tunnel at an adequate position rather than a conventional deviee. Twenty-six patients underwent transtibial pullout repairs using the Multi-use guide or the PRT guide that had a narrow twisting/curving shape. The MMPR anatomical center and tibial tunnel center were evaluated using the percentage-based posterolateral location on three-dimensional computed tomography images of the tibial surface (Tsukada's measurement method). Percentage distance between anatomical center and tunnel center was calculated. Anatomical center of the MMPR footprint located at a position of 78.5% posterior and 39.4% lateral. Both tunnels were anteromedial but tibial tunnel center located at a more favorable position in the PRT group. Percentage distance was significantly smaller in the PRT guide group (8.7%) than in the Multi-use guide group (13.1%). The PRT guide may have great advantage to achieve at a more anatomical location in MMPR pullout repair.

Computed Tomographic Evaluation of Bone Stock in Patients With Crowe Type III Developmental Dysplasia of the Hip: Implications for Guiding Acetabular Component Placement Using the High Hip Center Technique

BackgroundWe evaluated acetabular cup coverage (CC) and rim contact (RC) to evaluate the bone stock above the acetabulum for guiding acetabular component placement using the high hip center technique in patients with Crowe type III developmental dysplasia of the hip. MethodsUsing hip computed tomography and image processing software, pelvises were reconstructed digitally in 20 hips with Crowe type III developmental dysplasia of the hip. Mimicked cup was placed with anteversion angles of 0° (group I), 5° (group II), and 10° (group III) respectively. In each group, the cup was placed at the anatomical hip center at first, and then the cup was moved up to 40 mm vertically about the native rotation center with an increment of 2.5 mm at each step. CC and RC were calculated and documented with each movement. ResultsCC was 65.87%, 67.77%, and 68.98% for group I, group II, and group III at the native rotation center, and increased progressively to 86.45%, 85.85%, and 84.71% at 25 mm above. RC was 49.17%, 50.25%, and 51.92% for group I, group II, and group III at the native rotation center, and increased progressively to 86.87%, 86.39%, and 84.94% at 22.5 mm above. CC and RC were positively correlated, despite the different anteversion angles (r = 0.687 at 0°, 0.683 at 5°, and 0.645 at 10°; P < .001). ConclusionComputed tomography analysis and computer stimulation demonstrate that it is feasible to use high hip center technique in Crowe type III hips.

Restoration of the joint geometry and outcome after stemless TESS shoulder arthroplasty.

AIMTo evaluate the joint geometry and the clinical outcome of stemless, anatomical shoulder arthroplasty with the TESS system.METHODSTwenty-one shoulders with a mean follow-up 18 of months were included. On scaled digital radiographs the premorbid center of rotation (CoR) was assessed and compared to the CoR of the prosthesis by using the MediCAD® software. Additionally, the pre- and post-operative geometry of the CoR was assessed in relation to the glenoid, the acromion as well as to the proximal humerus. Radiological changes, such as radiolucencies, were also assessed. Clinical outcome was assessed with the Constant and DASH score.RESULTSBoth, the Constant and DASH scores improved significantly from 11% to 75% and from 70 to 30 points, P < 0.01 respectively. There were no significant differences regarding age, etiology, cemented or metal-backed glenoids, etc. (P > 0.05). The pre- and postoperative humeral offset, the lateral glenohumeral offset, the height of the CoR, the acromiohumeral distance as well as neck-shaft angle showed no significant changes (P > 0.05). The mean deviation of the CoR of the prosthesis from the anatomic center was 1.0 ± 2.8 mm. Three cases showed a medial deviation of more than 3 mm. These deviations of 5.1, 5.7 and 7.6 mm and were caused by an inaccurate humeral neck cut. These 3 patients showed a relatively poor outcome scoring.CONCLUSIONTESS arthroplasty allows an anatomical joint reconstruction with a very good outcome. Outliers described in this study sensitize the surgeon for an accurate humeral neck cut.

Some biomechanical features of medialization of the pressed and screwed-in cups in total hip arthroplasty in patients with dysplastic coxarthrosis

After total joint replacement in patients with dysplastic coxarthrosis, a significant number of negative results are observed. One of the ways of solving the problem of primary stability of the endoprosthetic cup is its mediation by deepening the acetabulum in the zone of its a natomical center.Objective: top erform a comparative biomechanical evaluation of the stability of the cups that are fastened and screwed up, in the event of their mediation performed under the conditions of joint replacement in patients with dysplastic coxarthrosis.Methods: with the help of mathematical modeling, the relatively strong characteristics of the pelvic bone in the area of the acetabulum and the quality of fixation of cup and cup after their mediation and immersion in the zone of the anatomical center of the depression. The total displacement of the head of the femoral component of the implant is analyzed.Results: it was found that using scintillating cup under the condition of dysplastic coxarthrosis provides total displacement in (2.2 ÷ 2.4) times greater than in the situations of its application without defect of the acetabulum. When the cup is pressed, the total displacement is 4.7 times larger than the screw cup. In these cases, hip replacement with the use of pressed cups is accompanied by a high risk of their primary instability.Conclusions: the use of screw-in cups in the case of their mediation under the conditions of total joint replacement in patients with dysplastic coxarthrosis provides a more reliable primary stability than the ones pushed into cups. The level of tension in the pelvic bone of the acetabulum is influenced by the depth of the cup setting, with the increase of which there is a significant destruction of bone tissue. It is advisable to carry out the hip joint replacement in the case of dysplastic coxarthrosis using a screw-in cup.

Is high hip center technique an acceptable choice for total hip arthroplasty of the developmental dysplasia of the hip?

Total hip arthroplasty (THA) is a successful method to treat osteoarthritis secondary to the developmental dysplasia of the hip (DDH). As anatomic deformity of acetabulum, anatomic hip center placing of the socket may lead insufficient host bone coverage, therefore, high hip center (HHC) technique is an alternative choice. Location of the hip rotation center can be referenced by inter teardrop line, the highest point of the obturator foramen, summit of the iliac crests, ischial tuberosities and other anatomic landmarks. The HHC technique is supposed to increase host bone coverage of socket without structural bone grafts, simplify surgical procedures, reduce anesthetic and surgical time, conserve adequate healthy bone stock for revision, however, it leads to insufficiency of the abductor muscles, is speculated to increase the hip load, lower the range of hip flexion and internal rotation (IR). Loosening rates and polyethylene wear vary in different studies. Concerning about these factors, HHC technique is acceptable while center of rotation located at a horizontal level with distance less than 35 mm from the inter teardrop line, moreover, medialization of these HHC reconstructions is suggested.

Impaction bone grafting with reinforcement metallic mesh and cemented cup for the treatment of Paprosky 3B acetabular defects

Depending on the bone defect, cup revision can be a highly complex operation. Cup loosening, produces cup migration and acetabular bone defects and the size of these bone defects will determine the technique used for acetabular cup revision. Migration of the cup also requires that to obtain a good clinical result, the center of rotation of the hip be reconstructed so the cup is played in the anatomic rotation center of the hip. The acetabular bone stock must be ideal to support the cup. There must be enough medial bone stock and supportive rims to obtain a long-term result.

Preliminary Model for the Design of a Custom Middle Ear Prosthesis.

Custom prostheses could be used to recreate the ossicular chain and improve hearing. Ossicular discontinuity or fixation occurs in 55% of cases of conductive hearing loss, with most cases involving the incus. Reconstruction has been achieved by a variety of methods; however, there has been little improvement in hearing outcomes in decades. Precise measurements of anatomic dimensions, weight, and center of gravity were taken from 19 cadaveric incudes. These measurements were combined with measurements from the medical literature and micro-computed tomography (micro-CT) of cadaveric temporal bones to generate a rasterizable incus model. As a proof of concept, incudal replacements including possible anatomic variations were then three-dimensionally (3-D) printed and inserted into a cadaveric temporal bone. Our measurements of cadaveric incudes corresponded well with those from the medical literature. These measurements were combined with anatomical information from micro-CT allowing identification of critical features of the incus, which remained constant. Other model features were modified to increase stability and facilitate synthesis, including broadening and thickening of the lenticular process and the incudomalleolar articulation. 3-D printed incudal replacements based on this model readily fit into a cadaveric temporal bone and successfully bridged the gap between malleus and incus. We have generated a model for custom 3-D synthesis of incudal prostheses. While current 3-D printing in biocompatible materials at the size required is limited, the technology is rapidly advancing, and 3-D printing of incudal replacements with polylactic acid (PLA) is of the correct size and shape.

Acetabular Reconstruction With the Medial Protrusio Technique for Complex Primary and Revision Total Hip Arthroplasties

BackgroundIn the setting of acetabular deficiency during total hip arthroplasty (THA), the medial protrusio technique (MPT) allows for increased component coverage while avoiding excessive component abduction or elevation of the hip center. The technique involves controlled reaming through the medial acetabular wall while maintaining the continuity of the anterior and posterior columns. The purpose of this study is to analyze the results of the largest reported series to date of primary and revision THAs using the MPT. MethodsA retrospective review of THAs performed by a single surgeon from July 2004 to July 2010 identified 102 patients who underwent THA necessitating the use of the MPT (primary 86 and revision 16), with at least 2 years follow-up. ResultsThis study reports the largest series to date of primary and revision THAs using the MPT for acetabular deficiency. Postoperatively, mean Harris hip score was 86 (range 31-96). There was no correlation with degree of medialization and change in Harris hip score (P = .12). At mean follow-up of 41.1 months (range 24-92 months), there were no intrapelvic structure injuries and no acetabular components required revision. The MPT provided a safe and effective method for addressing acetabular deficiency and avoiding component malposition. ConclusionThe MPT provided a safe and effective method for addressing acetabular deficiency in this large series of patients. The technique was successful at improving component coverage while maintaining an anatomic hip center and avoiding excessive component abduction. Fixation remained durable with no cases of loosening at final follow-up.

Fixation transtibiale des lésions de la racine postérieure du ménisque médial. Un guide de visée spécifique améliore le positionnement du tunnel tibial

IntroductionInjuries to the medial meniscus (MM) posterior root lead to accelerated cartilage degeneration of the knee. An anatomic placement of the MM posterior root attachment is considered to be critical in transtibial pullout repair of the medial meniscus posterior root tear (MMPRT). However, tibial tunnel creation at the anatomic attachment of the MM posterior root is technically difficult using a conventional aiming device. The aim of this study was to compare two aiming guides. We hypothesized that a newly-developed guide specifically designed creates the tibial tunnel at an adequate position rather than a conventional device. Materials and methodsTwenty-six patients underwent transtibial pullout repairs. Tibial tunnel creation was performed using the Multi-use guide (8 cases) or the PRT guide that had a narrow twisting/curving shape (18 cases). Three-dimensional computed tomography images of the tibial surface were evaluated using the Tsukada's measurement method postoperatively. Expected anatomic center of the MM posterior root attachment and tibial tunnel center were evaluated using the percentage-based posterolateral location on the tibial surface. Percentage distance between anatomic center and tunnel center was calculated. ResultsAnatomic center of the MM posterior root footprint located at a position of 78.5% posterior and 39.4% lateral. Both tunnels were anteromedial but tibial tunnel center located at a more favorable position in the PRT group: percentage distance was significantly smaller in the PRT guide group (8.7%) than in the Multi-use guide group (13.1%). DiscussionThe PRT guide may have great advantage to achieve a more anatomic location of the tibial tunnel in MMPRT pullout repair. Level of evidenceIV.

Accessory Spleen in the Greater Omentum: Embryology and Revisited Prevalence Rates

Purpose: To investigate in a large sample the prevalence rates of accessory spleens located in the greater omentum and to explain the embryological background and the vascular supply of this rare congenital disorder. Methods: Evaluation of the presence of accessory spleens located in the greater omentum was performed in 5 different international anatomical centers investigating a total of 1,045 body donors. Arterial and venous blood supply and the precise location of the respective vasculature within the splenic ligaments are described based on dissection of this rare condition in a male specimen. Results: The reported prevalence rates from 5 different centers were: 0.5% (out of 380 body donors), 0% (out of 230 donors), 0% (out of 200 donors), 2% (out of 200 donors), and 0% (out of 35 donors). The cumulative prevalence rate obtained from 1,045 anatomical dissections was 0.6%. The identified accessory spleen measured 3 × 3 × 2.5 cm and was located in the left upper abdominal quadrant. A vascular stag 7.5 cm in length was identified within the gastro-splenic ligament, containing an artery and a vein piercing the greater omentum from posterior. Conclusion: An accessory spleen located in the greater omentum is a rare congenital disorder. Physicians should be aware of the fact that in patients without any representative symptom history a nodular mass located within the greater omentum could be an accessory spleen.

FEATURES OF SURGICAL TACTICS FOR PATIENTS WITH COXO-VERTEBRAL SYNDROME

Purpose of the study – to design the algorithm of selection for rational surgical tactics for treatment of patients with coxo-vertebral syndrome.Material and methods. 175 patients with coxo-vertebral syndrome were included into the study who underwent total hip replacement in the period from 2009 till 2016. The authors analyzed outcomes of treatment of 134 patients at midterm follow up of 9 months (range from 8 to 10 months) after the surgery. Mean age of patients was 54,4±12,7 y.o. Patients were subdivided into a test group (94 patients) and control group (81 patients). Standard THR approaches were used in the control group by restoring anatomical center of rotation and lower leg length. The suggested algorithm of the optimal procedure selection was applied in the test group. Clinical and functional data was evaluated by Harris Hip Score and Oswestry score. Radiographic evaluation was performed based on x-rays of vertebral-pelvic complex in standing position, by functional x-rays, CT and MRI. Evaluation of differences significance between the groups was performed by MannWhitney U-test and McNemar test.Results. Application of proposed surgical approaches allowed to increase the number of patients with good clinical and functional outcomes (test group – 82,4%, control group – 26,7%) and achieve better function of hip joint and patients’ life quality in short-term postoperative period. Excellent outcomes by Harris hip score were observed in 53,2% of patients, in control group – in 9,7%. Share of the patients complaining of lumber pain, limping and need for a walking stick after THR in the test group was less than in control group. Share of patients demonstrating pain at palpation of spinous processes, with positive test of elevated extended leg and radicular syndrome was also significantly less in test group as compared to control group.Conclusion. Practical application of proposed algorithm for selection of a rational tactics of surgical treatment for patients with combined degenerative and distrophic pathology of the hip joint and spine allows in short-term after THR to statistically significantly improve treatment outcomes in comparison with patients that underwent conventional preoperative planning and THR.

Analysis of uncertainties in Monte Carlo simulated organ and effective dose in chest CT: scanner- and scan-related factors

In Monte Carlo simulation of CT dose, many input parameters are required (e.g. bowtie filter properties and scan start/end location). Our goal was to examine the uncertainties in patient dose when input parameters were inaccurate. Using a validated Monte Carlo program, organ dose from a chest CT scan was simulated for an average-size female phantom using a reference set of input parameter values (treated as the truth). Additional simulations were performed in which errors were purposely introduced into the input parameter values. The effects on four dose quantities were analyzed: organ dose (mGy/mAs), effective dose (mSv/mAs), CTDIvol-normalized organ dose (unitless), and DLP-normalized effective dose (mSv/mGy · cm). At 120 kVp, when spectral half value layer deviated from its true value by ±1.0 mm Al, the four dose quantities had errors of 18%, 7%, 14% and 2%, respectively. None of the dose quantities were affected significantly by errors in photon path length through the graphite section of the bowtie filter; path length error as large as 5 mm produced dose errors of ⩽2%. In contrast, error of this magnitude in the aluminum section produced dose errors of ⩽14%. At a total collimation of 38.4 mm, when radiation beam width deviated from its true value by ± 3 mm, dose errors were ⩽7%. Errors in tube starting angle had little impact on effective dose (errors ⩽ 1%); however, they produced organ dose errors as high as 66%. When the assumed scan length was longer by 4 cm than the truth, organ dose errors were up to 137%. The corresponding error was 24% for effective dose, but only 3% for DLP-normalized effective dose. Lastly, when the scan isocenter deviated from the patient’s anatomical center by 5 cm, organ and effective dose errors were up 18% and 8%, respectively.

A new aiming guide can create the tibial tunnel at favorable position in transtibial pullout repair for the medial meniscus posterior root tear

IntroductionInjuries to the medial meniscus (MM) posterior root lead to accelerated cartilage degeneration of the knee. An anatomic placement of the MM posterior root attachment is considered to be critical in transtibial pullout repair of the medial meniscus posterior root tear (MMPRT). However, tibial tunnel creation at the anatomic attachment of the MM posterior root is technically difficult using a conventional aiming device. The aim of this study was to compare two aiming guides. We hypothesized that a newly-developed guide, specifically designed, creates the tibial tunnel at an adequate position rather than a conventional device. Materials and methodsTwenty-six patients underwent transtibial pullout repairs. Tibial tunnel creation was performed using the Multi-use guide (8 cases) or the PRT guide that had a narrow twisting/curving shape (18 cases). Three-dimensional computed tomography images of the tibial surface were evaluated using the Tsukada's measurement method postoperatively. Expected anatomic center of the MM posterior root attachment and tibial tunnel center were evaluated using the percentage-based posterolateral location on the tibial surface. Percentage distance between anatomic center and tunnel center was calculated. ResultsAnatomic center of the MM posterior root footprint located at a position of 78.5% posterior and 39.4% lateral. Both tunnels were anteromedial but tibial tunnel center located at a more favorable position in the PRT group: percentage distance was significantly smaller in the PRT guide group (8.7%) than in the Multi-use guide group (13.1%). DiscussionThe PRT guide may have great advantage to achieve a more anatomic location of the tibial tunnel in MMPRT pullout repair. Level of evidenceIII.

Challenges in Total Hip Arthroplasty in the Setting of Developmental Dysplasia of the Hip

BackgroundDevelopmental dysplasia of the hip (DDH) is a recognized cause of secondary arthritis, which may eventually lead to total hip arthroplasty (THA). An understanding of the common acetabular and femoral morphologic abnormalities will aid the surgeon in preparing for the complexity of the surgical case. MethodsWe present the challenges associated with acetabular and femoral morphologies that may be present in the dysplastic hip and discuss surgical options to consider when performing THA. In addition, common complications associated with this population are reviewed. ResultsThe complexity of THA in the DDH patient is due to a broad range of pathomorphologic changes of the acetabulum and femur, as well as the diverse and often younger age of these patients. As such, THA in the DDH patient may offer a typical primary hip arthroplasty or be a highly complex reconstruction. It is important to be familiar with all the subtleties associated with DDH in the THA population. The surgeon must be prepared for bone deficiency when reconstructing the acetabulum and should place the component low and medial (at the anatomic hip center), and avoid oversizing the acetabular component. Femoral dysplasia is also complex and variable, and the surgeon must be prepared for different stem choices that allow for decoupling of the metaphyseal stem fit from the implanted stem version. In Crowe III and IV dysplasia, femoral derotation/shortening osteotomy may be required. Many complications associated with THA in the DDH patient may be mitigated with careful planning and surgical technique. ConclusionPerformed correctly, THA can yield excellent results in this complex patient population.

Anatomic Single-Bundle Anterior Cruciate Ligament Reconstruction Using the Modified Transtibial Technique

We present a technique for anterior cruciate ligament (ACL) reconstruction using hamstring tendon autograft with a modified transtibial technique. Our modified transtibial technique has the advantages of the conventional transtibial technique that is familiar to surgeons and that allows the press-fit fixing and enables us to make a relatively long femoral tunnel. To make the femoral tunnel at the anatomic position, the triangular, funnel-shaped bony trough was made to slip the eccentrically positioned guide pin into the anticipated anatomic center with a free-hand technique after marking the anatomic ACL footprint using a microfracture awl through the anteromedial portal. Gradual femoral reaming was performed with knee angle changes, which reduces the chances of posterior wall blowout, increases the femoral tunnel length, and avoids breakage of guide pin at the bending point. Our modified transtibial technique is anticipated to provide a more anatomic placement of the femoral tunnel during ACL reconstruction than the previous traditional transtibial techniques.

Total hip replacement in dysplastic hip joint dislocation

Objective: to assess current approaches to hip joint (HJ) ar­throplasty with high dysplastic dislocation and to evaluate out­comes. Methods: we studied the literature on the problem of to­tal hip arthroplasty under conditions of dysplastic coxarthrosis (DC) Crowe III–IV type classification and results of treatment in 322 patients (126 (39.1 %) — DC type III, 4 (4.4 %) — IV), wth domestic arthroplasty modular system with two types of ta­pered legs and two «dysplastic» with a square profile. Results: the main problem of hip joint arthroplasty in patients with DC Crowe III–IV type — selection of the optimal method of the femo­ral head construction, setting the cup on implant bed in the acetabulum (AC), prevention of cardiovascular and neurological complications. The method of low intertrochanteric osteotomy, femoral neck used in 126 cases (90 %) during the arthroplasty and length of limb offset from 2.8 to 4.5 cm without complica­tions. In 11 patients cup set to AC into true bed after osteotomy T. Paavilainen. In 3 cases subtrochanteric osteotomy performed with partial resection of the bone segment from 4 to 5 cm. Posi­tive results were obtained in 94.6 % of patients. Conclusions: in patients with DC III–IV type for Srowe when shortening the limb to 4 cm, treatment can be performed on the level or over minor trochanter intertrochanteric osteotomy, the release AC zone and immobilization of the proximal femur that saves its metaphysis and HJ muscular balance. In the case of complete dislocation of the femoral head with dysplastic genesis and shortening of the limbs over than 4 cm we recommend shorten­ing osteotomy together with the restoration of anatomic center of rotation of the head implant, ie setting the cup to the anatomic bed of AC combined with bone grafting defect in AC and use inserts 10o and 20o shed for prevent dislocation of the implant.