Insufficiency of the lateral collateral ligamentous complex causes posterolateral rotatory instability (PLRI). During reconstruction surgery the joint capsule is repaired, but its biomechanical influence on elbow stability has not been described. We hypothesized that capsular repair reduces ROM and varus angle after reconstruction of the lateral collateral complex. Six fresh frozen cadaveric elbow specimens were used.
Knee varus malalignment increases medial knee compartment loading and is associated with knee osteoarthritis (OA) progression and severity1. Altered biomechanical loading and dysregulation of joint tissue biology drive OA progression, but mechanistic links between these factors are lacking. Subchondral bone structural changes are biomechanically driven, involve bone resorption, immune cell influx, angiogenesis, and sensory nerve invasion, and contribute to joint destruction and pain2. We have investigated mechanisms underlying this involving RANKL and alkaline phosphatase (ALP), which reflect bone resorption and mineralisation respectively3 and the axonal guidance factor Sema3A. Sema3A is osteotropic, expressed by mechanically sensitive osteocytes, and an inhibitor of sensory nerve, blood vessel and immune cell invasion4. Sema3A is also differentially expressed in human OA bone5.HYPOTHESIS: Medial knee compartment overloading in varus knee malalignment patients causes dysregulation of bone derived Sema3A signalling directly linking joint biomechanics to pathology and pain. Synovial fluid obtained from 30 subjects with medial knee OA (KL grade II-IV) undergoing high tibial osteotomy surgery (HTO) was analysed by mesoscale discovery and ELISA analysis for inflammatory, neural and bone turnover markers. 11 of these patients had been previously analysed in a published patient-specific musculoskeletal model6 of gait estimating joint contact location, pressure, forces, and medial-lateral condyle load distribution in a published data set included in analyses. Data analysis was performed using Pearson's correlation matrices and principal component analyses. Principal Components (PCs) with eigenvalues greater than 1 were analysed.Abstract
OBJECTIVE
METHODS
To analyze the short-term outcome after medial open-wedge high tibial osteotomy with a 3D-printing technology in early medial keen osteoarthritis and varus malalignment. 32 knees(28 cases) of mOWHTO (fixation with an angular-stable TomoFix implant(Synthes)) with a 3D-printing technology combined with arhtroscopy were prospectively surveyed with regard to functional outcome(Hospital for special knee score [HSS] score). Pre- and postoperative tibial bone varus angle (TBVA), mechanical medial proximal tibial angle (MPTA), and alignment were analyzed with regard to the result.Objective
Design and Method
Cubitus varus following paediatric supra-condylar humeral fracture represents a complex three-dimensional malunion. This affects cosmesis, function and subsequent distal humeral fracture risk. Operative correction is however difficult with high complication rates. We present the 40-year Yorkhill experience of managing this deformity. From a total of 3220 supracondylar humeral fractures, 40 cases of post-traumatic cubitus varus were identified. There were ten undisplaced fractures, treated in cast, and thirty displaced fractures. Five were treated in cast, thirteen manipulated (MUA), four MUA+k-wires, seven ORIF (six k-wire, one steinman pin) and one in skeletal-traction. Sixteen malunions were treated operatively. The mean pre-operative varus was 19°. All had cosmetic concerns, three mild pain, one paraesthesia/weakness and three reduced movement (ROM). The operative indication was cosmetic in fifteen and functional in one (concern about instability). Twelve patients had lateral closing-wedge osteotomies; three complex/3D osteotomies (dome, unspecified rotational, antero-lateral wedge) and two had attempted 8-plate guided-growth correction. Complications occurred in eight patients (50 %): Fixation was lost in three (two staples, one k-wiring), incomplete correction in six (both 8-plates, both staples, two standard plates) and one early wound infection requiring metalwork removal resulting in deformity recurrence. One patient underwent revision lateral wedge osteotomy with full deformity correction but marked ROM restriction (20–100°) secondary to loose bodies. Those without complications were satisfied (50 %). All patients with residual deformity were unsatisfied. 1 patient with keloid scarring was unsatisfied despite deformity correction.
After anterior cruciate ligament reconstruction one of the risk factors for graft (re-)rupture is an increased posterior tibial slope (PTS). The current treatment for PTS is a high tibial osteotomy (HTO). This is a free-hand method, with 1 degree of tibial slope correction considered to be equal to 1 or even 1.67 mm of the anterior wedge resection. Error rates in the frontal plane reported in literature vary from 1 – 8.6 degrees, and in the sagittal plane outcomes in a range of 2 – 8 degrees are reported when planned on PTSs of 3 – 5 degrees. Therefore, the free-hand method is considered to have limited accuracy. It is expected that HTO becomes more accurate with patient specific saw guides (PSGs), with an accuracy margin reported in literature of 2 degrees. This proof of concept porcine cadaver case study aimed to investigate whether the use of PSGs improves the accuracy of HTO to less than 2 degrees. Secondly, the reproducibility of tibial slope measurement was evaluated. Preoperative MRI images of porcine cadaver knees (n = 3) were used to create 3D anatomical bone models (Mimics, Materialise, Belgium). These 3D models were subsequently used to develop PSGs (3-Matic, Materialise, Belgium) to correct all tibias for 3 degrees PTS and 4 degrees varus. The PSG mediated HTOs were performed by an experienced orthopaedic surgeon, after which postoperative MRI images were obtained. 3D anatomical models of postoperative tibias were created, and tibial slopes were assessed on both pre- and postoperative tibias. The tibial slope was defined as the angle between the mechanical axis and 3D tibial reference plane in the frontal and sagittal plane. The accuracy of the PSG mediated HTO (median and range) was defined as the difference in all possible combinations of the preoperatively planned and postoperatively obtained tibial slopes. To ensure reproducibility, the pre- and postoperative tibial slopes were measured thrice by one observer. The intra-class correlation coefficients (ICCs) were subsequently calculated to assess the intra-rater reliability (SPSS, IBM Corp., Armonk, N.Y., USA).Introduction and Objective
Materials and Methods
Constitutional knee varus increases the risk of medial OA disease due to increase in the knee adduction moment and shifting of the mechanical axis medially. Hueter-Volkmann’s law states that the amount of load experienced by the growth plate during development influences the bone morphology. For this reason, heightened sports activity during growth is associated with constitutional varus due to added knee adduction moment. In early OA, X-rays often show a flattened medial femoral condyle extension facet (EF). However, it is unknown whether this is a result of osteoarthritic wear, creep deformation over decades of use, or an outcome of Hueter-Volkmann’s law during development. A larger and flattened medial EF can bear more weight, due to increased load distribution. However, a flattened EF may also extrude the meniscus, leading meniscus degeneration and joint failure. Therefore, this study aimed to investigate whether varus knees have flattened medial EFs of both femur and tibia in a cohort of patients with no signs yet of bony attrition. Segmentation and morphology analysis was conducted using Materialise software (version 8.0, Materialise Inc., Belgium). This study excluded knees with bony attrition of the EFs based on Ahlbäck criteria, intraoperative findings, and operation notes history. Standard reference frames were used for both the femur and tibia to ensure reliable and repeatable measurements. The hip-knee-angle (HKA) angle defined varus or valgus knee alignment. Femur: The femoral EFs and flexion facets (FFs) had best-fit spheres fitted with 6 repetitions. Tibia: The slopes of the antero-medial medial tibial plateau were approximated using lines. Results 72 knees met the inclusion and exclusion criteria. The average age was 59 ± 11 years. The youngest was 31 and the oldest 84 years. Thirty-three were male and 39 were female. There was good intra- and inter-observer reliability for EF sphere fitting. Femur: The results demonstrated that the medial femoral condyle EF is flattened in knees with constitutional varus, as measured by the Sphere Ratios between the medial and lateral EF (varus versus straight: p = 0.006), and in the scaled values for the medial EF sphere radius (varus versus straight: p = 0.005). There was a statistically significant, moderate and positive correlation between the medial femoral EF radius, and the medial femoral EF-FF AP offset. Tibia: There was a statistically significant difference between the steepness of the slopes of the medial tibial plateau EF in varus and valgus knees, suggesting varus knees have a less concave (flatter) medial EF. Conclusions In comparison to straight knees, varus knees have flattened medial EFs in both femur and tibia. As this was the case in knees with no evidence of bony attrition, this could mean flattened medial EFs may be a result of medial physis inhibition during development, due to Hueter-Volkmann’s law. Flattened medial EFs may increase load distribution in the medial compartment, but could also be a potential aetiology in primary knee OA due to over extrusion of the medial meniscus and edge loading.
Posterolateral rotatory instability (PLRI) is the most common type of elbow instability. It is caused by an insufficiency of the lateral ligamentous complex, which consists mainly of the radial collateral ligament (RCL) and the lateral ulnar collateral ligament (LUCL). Investigate the influence of serial sectioning of the lateral ligamentous complex on elbow stability in a cadaveric model of PLRI. Kinematics of six fresh frozen cadaveric elbow specimens were measured by digitizing anatomical marks with a Microscribe 3DLX digitizing system (Revware Inc, Raleigh, NC). Each specimen was tested under four conditions: Intact, LUCL tear, LUCL and RCL tear, and complete Tear (LUCL, RCL and capsule tear). Each specimen was tested in 30°, 60° and 90° elbow flexion angles. Varus- laxity was measured in supination, pronation, and neutral forearm rotation positions and total forearm rotation was measured with 0.3 Nm of torque. Statistical significant differences between the conditions were detected using a two-way ANOVA with Tukey's post-hoc test. The radial head dislocated in all specimens in LUCL and RCL tear and Comp but not in LUCL tear. Total forearm ROM did not increase form intact to LUCL tear (p>0.05) but significantly increased in LUCL and RCL tear (p=0.0002) and complete tear (p<0.0001) in all flexion angles. Additionally, ROM in LUCL tear significantly differed from LUCL and RCL tear and complete tear (p=0.0027 and p=0.0002). A similar trend was seen with the varus angle. While there was a significant difference when the intact condition was compared to both the LUCLand RCL tear and complete tear conditions (p<0.0001 and p<0.0001), there was no difference between the intact and LUCL tear conditions. LUCL tear alone is not sufficient to cause instability and increase ROM and varus angle, meanwhile the increase of ROM and varus angle with additional capsular tear was not significant compared to LUCL and RCL tear. The increase of ROM after LUCL and RCL tear is an unknown symptom of PLRI.
Our objective was to perform a systematic review of the literature and conduct a meta- analysis to investigate the effect of initial varus or valgus displacement of proximal humerus on the outcomes of patients with proximal humerus fractures treated with open reduction and internal fixation. In accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement standards, we performed a systematic review. Electronic databases MEDLINE, EMBASE, CINAHL and the Cochrane Central Register of Controlled Trials (CENTRAL) were searched to identify randomised and non-randomised studies comparing postoperative outcomes associated with initial varus versus initial valgus displacement of proximal humerus fracture. The Newcastle–Ottawa scale was used to assess the methodological quality and risk of bias of the selected studies. Fixed-effect or random-effects models were applied to calculate pooled outcome data.Objectives
Methods
Osteonecrosis of the femoral head occurs in young patients. The preservation of the hip joint is vitally important, because hip arthroplasty does not guarantee satisfactory long-term results in young and active patients. Curved intertrochanteric varus osteotomy is one of several joint preserving procedures used for this disease. Between June 2004 and June 2007, 52 patients (55 hips) who had osteonecrosis of the femoral head were treated with curved intertrochanteric varus osteotomy. There were 29 men and 23 women who had a mean age at the time of osteotomy of 33 years (range, 18 to 52 years). The osteotomy was fixed with a 120 degree compression hip screw in the first 34 hips and with a 95 degree dynamic condylar screw in the remaining 21 hips. Clinical evaluation was performed using the scoring system of Merle d'Aubigne et al.Introduction
Methods
Transtrochanteric curved varus osteotomy is one of the effective joint-preserving operations for osteonecrosis (ON) of the femoral head. We correlated various factors with the radiological outcome of this procedure. We reviewed 74 hips in 63 patients who had a minimum follow-up of 5 years after transtrochanteric curved varus osteotomy for the treatment of ON. There were 28 men and 35 women who had a mean age of 33 years (range, 15 to 68 years) at the time of surgery. Clinical assessment was made based on the Harris hip score (HHS). Radiographically, we investigated various factors; affected lesion, stage and type (localization of the necrotic lesion) of ON, varus degree, post-operative intact ratio, progression of collapse, and joint-space narrowing. On the basis of postoperative radiographs, the hips were divided into 2 groups (Group I: either the progression of collapse or joint-space narrowing, Group II: neither progression of collapse or joint-space narrowing). The related factors with radiological outcome were analyzed by using multivariate analysis (Stepwise discriminant analysis).Introduction
Methods
Curved varus intertrochanteric osteotomy of the femur is an excellent and minimally invasive method for the treatment of osteonecrosis of the femoral head or osteoarthritis of the hip for joint preservation. However, the early postoperative complications of this procedure may be due to separation at the osteotomy site and an increase in varus angle due to early partial weight bearing. We modified the curved varus intertrochanteric osteotomy of the femur by performing an additional rotation. Regarding the surgical technique, curved varus osteotomy is performed at an angle of 30 degrees to the femoral shaft and an additional rotational osteotomy is also performed at an angle of 15 or 20 degrees to the osteotomy plane. Partial weight bearing with one-third body weight is permitted 3 weeks after surgery.Introduction
Methods
A transtrochanteric curved varus osteotomy (TCVO) is an excellent joint preserving surgical modality if the necrotic lesion can be moved to the non-weight bearing area as assessed by maximum abduction antero-posterior radiographs. The purpose of this article was to elucidate whether TCVO can reduce the volume of osteonecrosis after an index osteotomy as assessed by magnetic resonance imaging (MRI). Twenty patients (twenty hips) with non-traumatic osteonecrosis of the femoral head were followed for more than three years after an index operation and MRI examinations both before and at two years after surgery were retrospectively investigated. The average age at the time of operation was 40 years (range, 18 to 60 years), consisting of 13 men (13 hips) and 7 women (7 hips). The etiology and/or associated risk factors was steroid-associated osteonecrosis in 11 hips, alcohol associated in 7 hips, and idiopathic in 2. According to the classification of the Japanese Investigation Committee there was Type B in one hip, Type C-1 in 17 hips, and Type C-2 in 2 hips. Eight hips were in Stage 2, 10 in Stage 3A, and 2 in Stage 3B. Average follow-up was 4 years (range, 3 to 5 years).Introduction
Methods
The aim of this study was to determine whether the clinical outcome of autologous chondrocyte transplantation was dependent on the timing of a high tibial osteotomy in tibio-femoral mal-aligned knees. Between 2000 and 2005, forty-eight patients underwent autologous chondrocyte implantation with HTO performed at varying times relative to the second stage autologous chondrocyte implantation procedure. 24 patients had HTO performed simultaneously with their second stage cartilage transplantation, (the HTO Simultaneous Group). 5 patients had HTO prior to their cartilage procedure, (the HTO pre-ACI Group) and 19 had HTO performed between 1 to 4 years after their second stage cartilage implantation, (the HTO post-ACI Group). There were 29 men and 19 women with a mean age of 37 years (Range 28 to 50) at the time of their second stage procedure. With average follow-up of 72 months we have demonstrated a significant functional benefit in performing the HTO either prior to or simultaneously with the ACI procedure in the mal-aligned knee. The failure rate in the Post-ACI group was 45% compared to the Pre-ACI and Simultaneous group, with failure rates of 20% and 25%, respectively. An HTO performed prior to or simultaneously with an autologous chondrocyte implantation procedure in the mal-aligned knee, provides a significant protective effect by reducing the failure rate by approximately 50%.
Proximal humeral shaft fractures are commonly treated with long straight plates or intramedullary nails. Helical plates might overcome the downsides of these techniques as they are able to avoid the radial nerve distally. The aim of this study was to investigate in an artificial bone model: (1) the biomechanical competence of different plate designs and (2) to compare them against the alternative treatment option of intramedullary nails. Twenty-four artificial humeri were assigned in 4 groups and instrumented as follows: group1 (straight 10-hole-PHILOS), group2 (MULTILOCK-nail), group3 (45°-helical-PHILOS) and group4 (90°-helical-PHILOS). An unstable proximal humeral shaft fracture was simulated. Specimens were tested under quasi-static loading in axial compression, internal/external rotation and bending in 4 directions monitored by optical motion tracking. Axial displacement (mm) was significantly lower in group2 (0.1±0.1) compared to all other groups (1: 3.7±0.6; 3: 3.8±0.8; 4: 3.5±0.4), p<0.001.
Abstract. Objectives. Stem malalignment in total hip arthroplasty (THA) has been associated with poor long-term outcomes and increased complications (e.g. periprosthetic femoral fractures). Our understanding of the biomechanical impact of stem alignment in cemented and uncemented THA is still limited. This study aimed to investigate the effect of stem fixation method, stem positioning, and compromised bone stock in THA. Methods. Validated FE models of cemented (C-stem – stainless steel) and uncemented (Corail – titanium) THA were developed to match corresponding experimental model datasets; concordance correlation agreement of 0.78 & 0.88 for cemented & uncemented respectively. Comparison of the aforementioned stems was carried out reflecting decisions made in the current clinical practice. FE models of the implant positioned in varus, valgus, and neutral alignment were then developed and altered to represent five different bone defects according to the Paprosky classification (Type I – Type IIIb). Strain was measured on the femur at 0mm (B1), 40mm (B2), and 80mm (B3) from the lesser trochanter. Results. Cemented constructs had lower strain on the implant neck, and higher overall stiffness and strain on bone compared to uncemented THA. Strain on the bone increased further down the shaft of the femoral diaphysis, and with progressing bone defect severity in all stem alignment cases. Highest strain on the femur was found at B2 in all stem alignment and bone defect models.
Proximal humeral shaft fractures are commonly treated with long straight locking plates endangering the radial nerve distally. The aim of this study was to investigate the biomechanical competence in a human cadaveric bone model of 90°-helical PHILOS plates versus conventional straight PHILOS plates in proximal third comminuted humeral shaft fractures. Eight pairs of humeral cadaveric humeri were instrumented using either a long 90°-helical plate (group1) or a straight long PHILOS plate (group2). An unstable proximal humeral shaft fracture was simulated by means of an osteotomy maintaining a gap of 5cm. All specimens were tested under quasi-static loading in axial compression, internal and external rotation as well as bending in 4 directions. Subsequently, progressively increasing internal rotational loading until failure was applied and interfragmentary movements were monitored by means of optical motion tracking. Flexion/extension deformation (°) in group1 was (2.00±1.77) and (0.88±1.12) in group2, p=0.003.
Treatment of comminuted intraarticular calcaneal fractures remains controversial and challenging. Anatomic reduction with stable fixation has demonstrated better outcomes than nonoperative treatment of displaced intraarticular fractures involving the posterior facet and anterior calcaneocuboid joint (CCJ) articulating surface of the calcaneus. The aim of this study was to investigate the biomechanical performance of three different methods for fixation of comminuted intraarticular calcaneal fractures. Comminuted calcaneal fractures, including Sanders III-AB fracture of the posterior facet and Kinner II-B fracture of the CCJ articulating calcaneal surface, were simulated in 18 fresh-frozen human cadaveric lower legs by means of osteotomies. The ankle joint, medial soft tissues and midtarsal bones along with the ligaments were preserved. The specimens were randomized according to their bone mineral density to 3 groups for fixation with either (1) 2.7 mm variable-angle locking anterolateral calcaneal plate in combination with one 4.5 mm and one 6.5 mm cannulated screw (Group 1), (2) 2.7 mm variable-angle locking lateral calcaneal plate (Group 2), or (3) interlocking calcaneal nail with 3.5 mm screws in combination with 3 separate 4.0 mm cannulated screws (Group 3). All specimens were biomechanically tested until failure under axial loading with the foot in simulated midstance position. Each test commenced with an initial quasi-static compression ramp from 50 N to 200 N, followed by progressively increasing cyclic loading at 2Hz. Starting from 200 N, the peak load of each cycle increased at a rate of 0.2 N/cycle. Interfragmentary movements were captured by means of optical motion tracking. In addition, mediolateral X-rays were taken every 250 cycles with a triggered C-arm.
Introduction and Objective. Trochanteric fractures are associated with increasing incidence and represent serious adverse effect of osteoporosis. Their cephalomedullary nailing in poor bone stock can be challenging and associated with insufficient implant fixation in the femoral head. Despite ongoing implant improvements, the rate of mechanical complications in the treatment of unstable trochanteric fractures is high. Recently, two novel concepts for nailing with use of a helical blade – with or without bone cement augmentation – or an interlocking screw have demonstrated advantages as compared with single screw systems regarding rotational stability and cut-out resistance. However, these two concepts have not been subjected to direct biomechanical comparison so far. The aims of this study were to investigate in a human cadaveric model with low bone density (1) the biomechanical competence of cephalomedullary nailing with use of a helical blade versus an interlocking screw, and (2) the effect of cement augmentation on the fixation strength of the helical blade. Materials and Methods. Twelve osteoporotic and osteopenic femoral pairs were assigned for pairwise implantation using either short TFN-ADVANCED Proximal Femoral Nailing System (TFNA) with a helical blade head element, offering the option for cement augmentation, or short TRIGEN INTERTAN Intertrochanteric Antegrade Nail (InterTAN) with an interlocking screw. Six osteoporotic femora, implanted with TFNA, were augmented with 3 ml cement. Four study groups were created – group 1 (TFNA) paired with group 2 (InterTAN), and group 3 (TFNA augmented) paired with group 4 (InterTAN). An unstable pertrochanteric OTA/AO 31-A2.2 fracture was simulated. All specimens were biomechanically tested until failure under progressively increasing cyclic loading featuring physiologic loading trajectory, with monitoring via motion tracking. Results. T-score in groups 3 and 4 was significantly lower compared with groups 1 and 2, p=0.03. Stiffness (N/mm) in groups 1 to 4 was 335.7+/−65.3, 326.9+/−62.2, 371.5+/−63.8 and 301.6+/−85.9, being significantly different between groups 3 and 4, p=0.03.
