Aims. Guided growth has been used to treat coxa valga for cerebral palsy (CP) children. However, there has been no study on the optimal
Study design: A retrospective evaluation of
Minimizing tip-apex distance has been shown to reduce clinical failure of sliding hip screws used to fix peritro-chanteric fractures. The purpose of this study was to determine if such a relationship exists for the position of the lag screw in the femoral head using a cephalomedullary device. Methods: Thirty intact synthetic femur specimens (Model #3406, Pacific Research Laboratories, Vashon, WA) were potted into cement blocks distally for testing on an Instron 8874 (Instron, Canton, MA). A long cephalomedullary nail (Long Gamma 3 Nail, Stryker, Mahwah, NJ) was inserted into each of the femurs. An unstable four-part fracture was created, anatomically reduced, and repaired using one of 5 lag screw placements in the femoral head:. Superior (N=6),. Inferior (N=6),. Anterior (N=6),. Posterior (N=6),. Central (N=6). Mechanical tests were repeated for axial, lateral and torsional stiffness. All specimens were radiographed in the anterioposterior and lateral planes and tip-apex (TAD) distance was calculated. A calcar referenced tip-apex distance (CalTAD) was also calculated. ANOVA was used to compare means of the five treatment groups. Linear regression analysis was used to compare axial, lateral and torsional stiffness (dependant variables) to both TAD and CalTAD (independent variables). Results: ANOVA testing proved that the mean axial (p<
0.01) and torsional stiffness (p<
0.01) between the 5 groups was significantly different, but lateral stiffness was not statistically different (p=0.494). Post hoc analysis showed that the inferior lag
Purpose: Minimizing tip-apex distance (TAD) has been shown to reduce clinical failure of extramedullary sliding hip screws used to fix peritrochanteric fractures. There is debate regarding the optimal position of the lag screw in the femoral head when a cephalomedullary nail is used to treat a peritrochanteric fracture. Some authors suggest the TAD should be minimized as with an extramedullary sliding hip screw, while others suggest the lag screw should be placed inferior within the femoral head. The primary goal of this study was to determine which of 5 possible lag
Intra-operative Tip-Apex Distance (TAD) estimation optimises dynamic hip screw (DHS) placement during hip fracture fixation, reducing risk of cut-out. Thread-width of a standard DHS screw measures approximately 12.5 millimetres. We assessed the effect of introducing screw thread-width as an intra-operative distance reference to surgeons. The null hypothesis was that there were no differences between hip fracture fixation before and after this intervention. Primary outcome measure was TAD. Secondary outcome measures included position of the screw in the femoral head, quality of reduction, cut-out and surgeon accuracy of estimating TAD. 150 intra-operative DHS radiographs were assessed before and after introducing screw thread-width distance reference to surgeons. Mean TAD reduced from 19.37mm in the control group to 16.49mm in the prospective group (p=<0.001). The number of DHS with a TAD > 25mm reduced from 14% to 6%.
Introduction Concentric interference screw placement has been proposed as having potentially better biological graft integration than eccentric interference screw placement during soft tissue ACL reconstruction. The purpose of this study was to determine whether a wedge shaped concentric screw was at least equivalent to an eccentric screw in stiffness, yield load, ultimate load and mode of failure. Methods Seven matched pairs of human cadaveric tendon in porcine tibia with titanium wedge shaped screws were randomly allocated to either the eccentric or concentric groups. Bone tunnels were drilled 45° to the long axis of the tibia, akin to standard ACL reconstruction. Tendon diameter was matched to tunnel diameter and a screw one millimetre larger than tunnel diameter was inserted. An Instrom machine was used to pull in the line of the tendon. Tendons were inspected after construct disassembly. Results The concentric screw configuration showed significantly higher stiffness (p<
0.0085), yield load (p<
0.0135) and ultimate load (p<
0.0075). The mode of failure in the eccentric
Biomechanical stability is important for fracture healing. With standard plate and screw constructs, longer plates with screws well spaced, near and far from the fracture site, are biomechanically superior. Newer locked plates have been shown to be superior to conventional plating for difficult fractures. The ideal screw configuration for fixation with locked plates has yet to be addressed. This study investigates the effects of
Introduction: Since the introduction of locked implants new possibilities in the treatment of proximal humeral fractures have evolved. Despite the success using locked plates recent publications report the cutting of screws through the humeral head in up to 30% of the cases. The distribution of the bone strength in the humeral head is not linear. Can polyaxial
Open-wedge high tibial osteotomy (OWHTO) is an operation involving proper load re-distribution in the treatment for medial uni-compartmental arthritis of the knee joint. Therefore, stable fixation is mandatory for safe healing of this additive type of osteotomy to minimize the risk of non-union and loss of correction. For stability, screws provide optimal support and anchorage of the fixator in the condylar area without risking penetration of either the articulating surface. The purpose of the study was to evaluate the screw insertion angle and orientation with an anatomical plate that is post-contoured to the surface geometry of the proximal tibia after OWHTO. From March 2012 to June 2014, 31 uni-planar and 38 bi-planar osteotomies were evaluated. Postoperative computed tomography data obtained after open wedge high tibial osteotomy using a locking plate were used for reconstruction of the 3 dimensional model with Mimics v.16.0 of the proximal tibia and locking plate. Measurement data were compared between 2 groups (gap lesser than or equal to 10 mm (Group 1) and gap greater than 10 mm(Group 2)). These data were also compared between the uniplanar (Group 3) and bi-planar (Group 4) osteotomy groups.Background
Methods
The purpose of this study was to evaluate the
risk of late displacement after the treatment of distal radial fractures with
a locking volar plate, and to investigate the clinical and radiological
factors that might correlate with re-displacement. From March 2007
to October 2009, 120 of an original cohort of 132 female patients
with unstable fractures of the distal radius were treated with a
volar locking plate, and were studied over a follow-up period of
six months. In the immediate post-operative and final follow-up
radiographs, late displacement was evaluated as judged by ulnar
variance, radial inclination, and dorsal angulation. We also analysed
the correlation of a variety of clinical and radiological factors
with re-displacement. Ulnar variance was significantly overcorrected
(p <
0.001) while radial inclination and dorsal angulation were
undercorrected when compared statistically (p <
0.001) with the unaffected
side in the immediate post-operative stage. During follow-up, radial
shortening and dorsal angulation progressed statistically, but none
had a value beyond the acceptable range. Bone mineral density measured
at the proximal femur and the position of the screws in the subchondral
region, correlated with slight progressive radial shortening, which
was not clinically relevant. Volar locking plating of distal radial fractures is a reliable
form of treatment without substantial late displacement. Cite this article:
Soft tissue balancing in total knee replacement may well be the determining factor in raising the fair patient satisfaction. The development of intelligent implants allows quantification of reactive loads to applied pressures. This can be tested in dynamic mode such as heel push test at surgery, or in static mode such as when testing for varus/valgus (VV) laxity of the collateral ligaments of the knee. We postulate that a well-balanced knee will have comparable if not equal load distribution across compartments in dynamic loading. When tested for laxity, we anticipate an equal or comparable response to VV applied loads under physiologic load range of 10–50N. This study sought to analyze the relationship between the kinematic (joint motion) and kinetic (force) effects to VV testing in the 0–15 degrees range of flexion. One goal was to demonstrate that testing the knee in locked extension (Screw Home effect) is unreliable and should be abandoned in favor of the more reliable VV testing at 10–15 degrees of flexion. This is a preliminary cadaveric study utilizing data from two hemibodies. The pelvis was fixed in a custom test rig with open or closed chain lower leg testing capability along a sliding rail with foot VV translational. Forces were applied at the malleoli with a wireless hand held dynamometer. Kinematic analysis of the hip-knee-ankle (HKA) tibiofemoral angle was derived from a commercial navigation system with mounted infrared trackers. Kinetic analysis was derived from a commercially available sensor imbedded in a tibial trial liner. Balance was optimized by conventional methods with the use of the sensor feedback until loads were roughly symmetrical and VV testing yielded symmetrical rise in opposite compartments. The VV testing was then performed with the knees locked at the femoral side in axial rotation and translational motion in any plane. Sagittal flexion was pre-set at 0, 10, and 15 degrees and progressive load was applied. From the graphs one can observe significant differences between VV testing at 0 degrees (locked Screw Home), 10 degrees, and 15 degrees of flexion. The shaded area corresponds to the common range of VV stress testing loading pressure, typically less than 35N. The HKA deviates from neutrality no sooner than by the middle of the physiologic test zone. By 35N, the magnitude of the effect is also much less than that observed at 10 and 15 degrees (unlocked from Screw Home). From the kinetic analysis one can also note the significant difference in the High-Low spread throughout the testing range of applied pressure. If the surgeon tests in the low range of applied loads, he/she may not observe the kinematic joint opening effect. The kinetic effect seems more reliable as sensed loads are detectable earlier on. It is clear however that testing at 10–15 degrees offers a much better sensitivity to the VV laxity or stiffness as exemplified in the bottom portions of the figure. Therefore testing in locked Screw Home full extension may lead to underestimation of the true coronal laxity of the joint.Results
Lag screw cut-out is a serious complication of dynamic hip screw fixation in trochanteric hip fractures. Lag
Reverse shoulder arthroplasty (RSA) is commonly used to treat patients with rotator cuff tear arthropathy. Loosening of the glenoid component remains one of the principal modes of failure and is the main complication leading to revision. For optimal RSA implant osseointegration to occur, the micromotion between the baseplate and the bone must not exceed a threshold of 150 µm. Excess micromotion contributes to glenoid loosening. This study assessed the effects of various factors on glenoid baseplate micromotion for primary fixation of RSA. A half-fractional factorial experiment design (2k-1) was used to assess four factors: central element type (central peg or screw), central element cortical engagement according to length (13.5 or 23.5 mm), anterior-posterior (A-P) peripheral screw type (nonlocking or locking), and bone surrogate density (10 or 25 pounds per cubic foot [pcf]). This created eight unique conditions, each repeated five times for 40 total runs. Glenoid baseplates were implanted into high- or low-density Sawbones™ rigid polyurethane (PU) foam blocks and cyclically loaded at 60 degrees for 1000 cycles (500 N compressive force range) using a custom designed loading apparatus. Micromotion at the four peripheral
Aims. Paediatric triplane fractures and adult trimalleolar ankle fractures both arise from a supination external rotation injury. By relating the experience of adult to paediatric fractures, clarification has been sought on the sequence of injury, ligament involvement, and fracture pattern of triplane fractures. This study explores the similarities between triplane and trimalleolar fractures for each stage of the Lauge-Hansen classification, with the aim of aiding reduction and fixation techniques. Methods. Imaging data of 83 paediatric patients with triplane fractures and 100 adult patients with trimalleolar fractures were collected, and their fracture morphology was compared using fracture maps. Visual fracture maps were assessed, classified, and compared with each other, to establish the progression of injury according to the Lauge-Hansen classification. Results. Four stages of injury in triplane fractures, resembling the adult supination external rotation Lauge-Hansen stages, were observed. Stage I consists of rupture of the anterior syndesmosis or small avulsion of the anterolateral tibia in trimalleolar fractures, and the avulsion of a larger Tillaux fragment in triplanes. Stage II is defined as oblique fracturing of the fibula at the level of the syndesmosis, present in all trimalleolar fractures and in 30% (25/83) of triplane fractures. Stage III is the fracturing of the posterior malleolus. In trimalleolar fractures, the different Haraguchi types can be discerned. In triplane fractures, the delineation of the posterior fragment has a wave-like shape, which is part of the characteristic Y-pattern of triplane fractures, originating from the Tillaux fragment. Stage IV represents a fracture of the medial malleolus, which is highly variable in both the trimalleolar and triplane fractures. Conclusion. The paediatric triplane and adult trimalleolar fractures share common features according to the Lauge-Hansen classification. This highlights that the adolescent injury arises from a combination of ligament traction and a growth plate in the process of closing. With this knowledge, a specific sequence of reduction and optimal
Aims. To develop a core outcome set of measurements from postoperative radiographs that can be used to assess technical skill in performing dynamic hip screw (DHS) and hemiarthroplasty, and to validate these against Van der Vleuten’s criteria for effective assessment. Methods. A Delphi exercise was undertaken at a regional major trauma centre to identify candidate measurement items. The feasibility of taking these measurements was tested by two of the authors (HKJ, GTRP). Validity and reliability were examined using the radiographs of operations performed by orthopaedic resident participants (n = 28) of a multicentre randomized controlled educational trial (ISRCTN20431944). Trainees were divided into novice and intermediate groups, defined as having performed < ten or ≥ ten cases each for DHS and hemiarthroplasty at baseline. The procedure-based assessment (PBA) global rating score was assumed as the gold standard assessment for the purposes of concurrent validity. Intra- and inter-rater reliability testing were performed on a random subset of 25 cases. Results. In total, 327 DHS and 248 hemiarthroplasty procedures were performed by 28 postgraduate year (PGY) 3 to 5 orthopaedic trainees during the 2014 to 2015 surgical training year at nine NHS hospitals in the West Midlands, UK. Overall, 109 PBAs were completed for DHS and 80 for hemiarthroplasty. Expert consensus identified four ‘final product analysis’ (FPA) radiological parameters of technical success for DHS: tip-apex distance (TAD); lag
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
Recently, a new generation of superior clavicle plates was developed featuring the variable-angle locking technology for enhanced
Introduction and Objective. The aim of this study was to evaluate whether CT-based pre-operative planning, integrated with intra-operative navigation could improve glenoid baseplate fixation and positioning by increasing screw length, reducing number of screws required to obtain fixation and increasing the use of augmented baseplate to gain the desired positioning. Reverse total shoulder arthroplasty (RSA) successfully restores shoulder function in different conditions. Glenoid baseplate fixation and positioning seem to be the most important factors influencing RSA survival. When scapular anatomy is distorted (primitive or secondary), optimal baseplate positioning and secure screw purchase can be challenging. Materials and Methods. Twenty patients who underwent navigated RSA (oct 2018 and feb 2019) were compared retrospectively with twenty patients operated on with a conventional technique. All the procedures were performed by the same surgeon, using the same implant in cases of eccentric osteoarthritis or complete cuff tear. Exclusion criteria were: other diagnosis as proximal humeral fractures, post-traumatic OA previously treated operatively with hardware retention, revision shoulder arthroplasty. Results. The NAV procedure required mean 11 (range 7–16) minutes more to performed than the conventional procedure. Mean screw length was significantly longer in the navigation group (35.5+4.4 mm vs 29.9+3.6 mm; p . .001). Significant higher rate of optimal fixation using 2 screws only (17 vs 3 cases, p . .019) and higher rate of augmented baseplate usage (13 vs 4 cases, p . .009) was also present in the navigation group. Signficant difference there is all in function outcomes, DASH score is 15.7 vs 29.4 and constant scale 78.1 vs 69.8. Conclusions. The glenoid component positioning in RSA is crucial to prevent failure, loosening and biomechanical mismatch, coverage by the baseplate of the glenoid surface, version, inclination and offset are all essential for implant survival. This study showed how useful 3D CT-based planning helps in identifying the best position of the metaglena and the usefulness of receiving directly in the operation theater real-time feedback on the change in position. This study shows promising results, suggesting that improved baseplate and
Summary Statement. In this study, excellent positioning of custom-made glenoid components was achieved using patient-specific guides. Achieving the preoperatively planned orientation of the component improved significantly and more screws were located inside the scapular bone compared to implantations without such guide. Introduction. Today's techniques for total or reverse shoulder arthroplasty are limited when dealing with severe glenoid defects. The available procedures, for instance the use of bone allografts in combination with available standard implants, are technically difficult and tend to give uncertain outcomes (Hill et al. 2001; Elhassan et al. 2008; Sears et al. 2012). A durable fixation between bone and implant with optimal fit and implant positioning needs to be achieved. Custom-made defect-filling glenoid components are a new treatment option for severe glenoid defects. Despite that the patient-specific implants are uniquely designed to fit the patient's bone, it can be difficult to achieve the preoperatively planned position of the component, resulting in less optimal screw fixation. We hypothesised that the use of a patient-specific guide would improve implant and
Introduction:- We reviewed 69 patients with subcapital fracture neck of femur treated with two hole plate DHS and parallel de-rotation screw into the cranial part of the femoral head between January 2000 to January 2005. Methods:- Patients were selected for fixation by having Garden 1 to 4 fractures, being younger, more active and mobile. Reduction was classified as “good” when residual angulation in the lateral projection was less than 15 degrees, no varus angulation and good alignment in the calcar area.
