The triangular fibrocartilage complex (TFCC) is a known stabiliser of the distal radioulnar joint (DRUJ). An injury to these structures can result in significant disability including pain, weakness and joint stiffness. The contribution each of its components makes to the stability of the TFCC is not well understood. This study was undertaken to investigate the role of the individual ligaments of the TFCC and their contribution to joint stability. The study was undertaken in two parts. 30 cadaveric forearms were studied in each group. The ligaments of the TFCC were progressively sectioned and the resulting effect on the stability of the DRUJ was measured. A custom jig was created to apply a 20N force through the distal radius, with the ulna fixed. Experiment one measured the effect on DRUJ translation after TFCC sectioning. Experiment two added the measurement of rotational instability. Part one of the study showed that complete sectioning of the TFCC caused a mean increase in translation of 6.09(±3) mm. Sectioning the palmar radioulnar ligament of the TFCC caused the most translation. Part two demonstrated a change in rotation with a mean of 18 (± 6) degrees following sectioning of the TFCC. There was a progressive increase in rotational instability until the palmar radioulnar ligament was also sectioned. Linear translation consistently increased after sectioning all of the TFCC ligaments, confirming its importance for DRUJ stability. Sectioning of the palmar radioulnar ligament most commonly caused the greatest degree of translation. This suggests injury to this ligament would more likely result in a greater degree of translational instability. The increase in rotation also suggests that this type of instability would be symptomatic in a TFCC injury

Introduction. IM (Intra Medullary) nail fixation is the standard treatment for diaphyseal femur fractures and also for certain types of proximal and distal femur fractures. Despite the advances in the tribology for the same, cases of failed IM nail fixation continue to be encountered routinely in clinical practice. Common causes are poor alignment or reduction, insufficient fixation and eventual implant fatigue and failure. This study was devised to study such patients presenting to our practice and develop a predictive model for eventual failure. Materials and Methods. 57 patients who presented with failure of IM nail fixation (± infection) between Jan 2011 – Jun 2020 were included in the study and hospital records and imaging reviewed. Those fixed with any other kinds of metalwork were excluded. Classification for failure of IM nails – Type 1: Failure with loss of contact of lag screw threads in the head due to backing out and then rotational instability, Type 2A: Failure of the nail at the nail and lag screw junction, Type 2B: Failure of the screws at the nail lag screw junction, Type 3: Loosening at the distal locking sites with or without infection. X-rays reviewed and causes/site of failure noted. Results. Total patients - 57. Demography - Average age - 58.9 years, 22 Males and 35 females. Eleven patients were noted to have an infection at the fracture site that needed oral or IV antibiotics.16 patients - at least 1 cerclage wire for fracture reduction and fixation + IM Nail. Subtrochanteric fractures (42/57) were the most common to fail. In those fractures with postero-medial comminution, locking of the lag screw in position thus preventing backout can prevent failure. In type 2 failures, preventing varus fixation by early open reduction and temporary fixation with plates and screws can achieve improved results. Those with type 3 failures with periosteal reaction should be considered to be infected until proven otherwise. Conclusions. This classification for failure of IM nails in the femur can be used as a predictive model for failures and allow early recognition and intervention to tackle them

Introduction. Clinical observations suggest mid-flexion instability may occur more commonly with rotating platform (RP) total knee arthroplasty (TKA), including increased revision rates and patient-reported instability and pain. We propose that increased gap laxity leads to liftoff of the lateral femoral condyle with decreased conformity between the femoral component and polyethylene (PE) insert surface leading to PE subluxation or dislocation. The objectives of this study were to define “at risk” loading conditions that predispose patients to PE insert subluxation or spinout, and to quantify the margin of error for flexion/extension gap laxity in preventing these adverse events under physiologic loading conditions. Methods. Biomechanical testing was performed on six fresh frozen cadaveric knees implanted with a posterior stabilized RP TKA using a gap balancing technique. Rotational displacement and torque were measured over time, while stiffness, yield torque, max torque and displacement were calculated using a post-processing, custom MatLab code. Revision with varying size femoral components (size 3–6) and PE insert thicknesses (10–15mm), by downsizing one step, were used to create a spectrum of flexion/extension gap mismatch. Each configuration was subjected to three loaded testing conditions (0°, 30° and 60° flexion) in balanced and eccentric varus loading, known to represent daily clinical function and “at risk” circumstances. Results. PE insert rotational instability was primarily determined by conformity and contact area between the femoral condyle and the upper surface of the PE insert. In this RP design, contact area is known to decrease with flexion greater than 35°, which predisposed to abnormal motion of the femur on PE insert (Figure 1). Under all flexion/extension gap testing conditions, PE insert rotational displacement significantly decreased with increasing knee flexion (differences ranged from 0.42 to 1.01cm, p<0.05), confirming that decreased conformity allows unintended motion to occur on the upper rather than the lower insert surface, as kinematically designed. This decrease in insert rotation was further exacerbated with eccentric medial-sided loading (differences ranged from 0.77 to 1.18cm, p<0.05). Yield torque (19.66±6.79N-m, p=0.033) and max torque (19.76±5.93N-m, p=0.014) significantly increased with increasing flexion from 0° to 60° under gap balanced conditions. Yield torque significantly decreased with greater flexion gap laxity at 60° of flexion (−24.82±5.96N-m, p=0.004). The depth of the lateral PE insert concavity (1.7–3.6mm) varied with insert size and thickness and determined femoral condylar capture. The lateral insert concavity defines a narrow margin of error in flexion/extension gap asymmetry leading to rotational insert instability, especially in smaller sized knees (size 3) where the jump height (1.7mm) is less than the insert sizing increment of 2.5mm. Conclusions. Contact area is known to decrease with flexion greater than 35° in this TKA-RP design. Flexion gap laxity further increased the risk of unintended top-side rotation of the femur on the insert, especially with increasing flexion and smaller components. In RP-TKA, in addition to medial-lateral gap symmetry and flexion-extension balance, a snug flexion gap with less than 2mm lateral laxity is critical to avoid insert instability and condylar escape with insert subluxation. For any figures or tables, please contact authors directly

Previous biomechanical studies of lateral collateral ligament (LCL) injuries and their surgical repair, reconstruction and rehabilitation have primarily relied on gravity effects with the arm in the varus position. The application of torsional moments to the forearm manually in the laboratory is not reproducible, hence studies to date likely do not represent forces encountered clinically. The aim of this investigation was to develop a new biomechanical testing model to quantify posterolateral stability of the elbow using an in vitro elbow motion simulator. Six cadaveric upper extremities were mounted in an elbow motion simulator in the varus position. A threaded screw was then inserted on the dorsal aspect of the proximal ulna and a weight hanger was used to suspend 400g, 600g, and 800g of weight from the screw head to allow torsional moments to be applied to the ulna. An LCL injured (LCLI) model was created by sectioning of the common extensor origin, and the LCL. Ulnohumeral rotation was recorded using an electromagnetic tracking system during simulated active and passive elbow flexion with the forearm pronated and supinated. A repeated measures analysis of variance was performed to compare elbow states (intact, LCLI, and LCLI with 400g, 600g, and 800g of weight). During active motion, there was a significant difference between different elbow states (P=.001 pronation, P=.0001 supination). Post hoc analysis showed that the addition of weights did not significantly increase the external rotation (ER) of the ulnohumeral articulation (10°±7°, P=.268 400g, 10.5°±7.1°, P=.156 600g, 11°±7.2°, P=.111 800g) compared to the LCLI state (8.4°±6.4°) with the forearm pronated. However, with the forearm supinated, the addition of 800g of weight significantly increased the ER (9.2°±5.9°, P=.038) compared to the LCLI state (5.9°±5.5°) and the addition of 400g and 600g of weights approached significance (8.2°±5.7°, P=.083 400g, 8.7°±5.9°, P=.054 600g). During passive motion, there was a significant difference between different elbow states (P=.0001 pronation, P=.0001 supination). Post hoc analysis showed that the addition of 600g and 800g but not 400g resulted in a significant increase in ER of the ulnohumeral articulation (9.3°±7.8°, P=.103 400g, 11.2°±6.2°, P=.004 600g, 12.7°±6.8°, P=.006 800g) compared to the LCLI state (3.7°±5.4°) with the forearm pronated. With the forearm supinated, the addition of 400g, 600g, and 800g significantly increased the ER (11.7°±6.7°, P=.031 400g, 13.5°±6.8°, P=.019 600g, 14.9°±6.9°, P=.024 800g) compared to the LCLI state (4.3°±6.6°). This investigation confirms a novel biomechanical testing model for studying PLRI. Moreover, it demonstrates that the application of even small amounts of torsional moment on the forearm with the arm in the varus position exacerbates the rotational instability seen with the LCL deficient elbow. The effect of torsional loading was significantly worse with the forearm supinated and during passive elbow motion. This new model allows for a more provocative testing of elbow stability after LCL repair or reconstruction. Furthermore, this model will allow for smaller sample sizes to be used while still demonstrating clinically significant differences. Future biomechanical studies evaluating LCL injuries and their repair and rehabilitation should consider using this testing protocol

INTRODUCION. Appropriate soft tissue balance is an important factor for postoperative function and long survival of total knee arthroplasty(TKA). Soft tissue balance is affected by ligament release, osteophyte removal, order of soft tissue release, cutting angle of tibial surface and rotational alignment of femoral components. The purpose of this study is to know the characteristics of soft tissue balance in ACL deficient osteoarthritis(OA) knee and warning points during procedures for TKA. METHODS. We evaluated 139 knees, underwent TKA (NexGen LPS-Flex, fixed surface, Zimmer) by one surgeon (S.A.) for OA. All procedures were performed through a medial parapatellar approach. There were 49 ACL deficient knees. A balanced gap technique was used in 26 ACL deficient knees, and anatomical measured technique based on pre-operative CT was used in 23 ACL deficient knees. To compare flexion-extension gaps and medial- lateral balance during operations between the two techniques, we measured each using an original two paddles tensor (figure 1) at 20lb, 30lb and 40lb, for each knee at a 0 degree extension and 90 degree flexion. We measured bone gaps after removal of all osteophytes and cutting of the tibial surface, then we measured component gaps after insertion of femoral components. Statistical analysis was performed by t-test with significant difference defined as P<0.05. RESULTS. (1) There were 90 ACL remaining knees and 49 deficient knees. Each group's preoperative FTA was 184±4.4 degrees, 187±6.3 degrees, postoperative FTA was 174±2.7 degrees, 173±3.1 degrees, preoperative knee extension was −12.8±7.5 degrees, −14.5.±3.1 degrees, flexion was 122.4±13.7 degrees, 110.7±20.2 degrees, post-operative β angle was, 88.1±2.5 degrees, 88.5±2.5 degrees. Comparing bone gap, medial gap and lateral-medial gap at a 30lb flexion were significantly different(P<0.05). (2) Comparing component gaps using modified gap techniques (group G) and anatomical techniques (group A) in ACL deficient knees, extension of medial and lateral gaps at 30lb and 40 lb in anatomical technique was bigger. The lateral-medial gap at 30lb was bigger in anatomical techniques. (P<0.05). DISCUSSION. The present results showed that ACL deficient OA knee were looser at medial side compared with ACL remaining OA knees. It indicates that we performed medial rerelease carefully in ACL deficient TKA. When we used gap techniques, medial loosening caused malposition of femoral components, and when we used anatomical techniques, extension gap was bigger than using gap techniques because generally smaller femoral components were chosen. It is reported that lateral gaps are bigger in severe varus deformity OA than slightly deformed OA knees and the soft tissue on the medial side is not shorter. It is also reported the correlation of lateral thrust with ACL deficiency and the progression OA, and when OA is developed, lateral side becomes loose. Our study indicated that ACL deficient OA knee progress rotational instability, in addition to antero-posterior instability, and subsequent medial loosening and development of medial osteophyte. Medial preserving gap technique is recommended

Introduction. Many factors can influence post-operative kinematics after total knee arthroplasty (TKA). These factors include intraoperative surgical conditions such as ligament release or quantity of bone resection as well as differences in implant design. Release of the medial collateral ligament (MCL) is commonly performed to allow correction of varus knee. Precise biomechanical knowledge of the individual components of the MCL is critical for proper MCL release during TKA. The purpose of this study was to define the influences of the deep medial collateral ligament (dMCL) and the posterior oblique ligament (POL) on valgus and rotatory stability in TKA. Materials and Methods. This study used six fresh-frozen cadaveric knees with intact cruciate ligaments. All TKA procedures were performed by the same surgeon using CR-TKA with a CT-free navigation system. Each knee was tested at 0°, 20°, 30°, 60°, and 90° of flexion. One sequential sectioning sequence was performed on each knee, beginning with an intact knee (S0), and thereafter femoral arthroplasty only (S1), tibial arthroplasty (S2), release of the dMCL (S3), and finally, release of the POL (S4). The same examiner applied all external load of 10 N-m valgus and a 5 N-m internal and external rotation torque at each flexion angle for the each cutting state. All data were analyzed statistically using one-way ANOVA and we investigated the correlation between the medial gap and the rotation angle. A significant difference was determined to be present for P < .05. Results. There were no correlation between the medial gap and the rotation angle in S0. A moderate correlation was found in S1 at 0° and 20°, and a considerable correlation was found in S2 at 90°. There was a correlation at all angles in S4, and especially strong at 20°, 60°, 90°. Conclusion. From this study, there were no correlation between medial knee instability and total rotation angles after performing TKA only by releasing dMCL, but by adding POL release, there were correlation in all angles. Therefore, medial knee instability caused by excessive release of the main medial knee structures may promote rotational instability

Aims

A functional anterior cruciate ligament (ACL) or posterior cruciate ligament (PCL) has been assumed to be required for patients undergoing unicompartmental knee arthroplasty (UKA). However, this assumption has not been thoroughly tested. Therefore, this study aimed to assess the biomechanical effects exerted by cruciate ligament-deficient knees with medial UKAs regarding different posterior tibial slopes.

Background. External fixation for a fracture-dislocation to a joint like the elbow, while maintaining joint mobility is currently done after identifying the center of rotation under X-ray guidance, when applying either a mono-lateral or a circular fixator. Current treatment. using the galaxy fixation system by Orthofix, the surgeon needs to correctly identify the center of rotation of the elbow under X-ray guidance on lateral views. If the center of rotation of the fixator is not aligned with that of the elbow joint, the assembly will not work, i.e. the elbow will be disrupted on trying to achieve flexion or extension movements. Figures (A, B, C and D) summarize the critical steps in identifying the centre of rotation (Courtesy of Orthofix Orthopedics International). New design. This new idea aims to propagate the principle of sliding external fixation applied on the extensor side of a joint, with the limbs of the fixator being able to slide in and out during joint extension and flexion respectively, without hindering the joint movement. Taking the ulno-humeral joint as an example, it is enough to apply the sliding external fixator in line with the subcutaneous border of the ulna, and the pins in the sagital plane, without the need to use x-ray guidance to identify the center of rotation, which simplifies the procedure, and makes it less technically demanding. The sliding external fixator over the elbow involves two bars which accommodate half pins fixation with headless grip screws to hold the pins, identical to the Rancho cubes technique by Smith & Nephew, these slide snugly into sleeves, those sleeves linked together through a hinge behind the elbow, and the bars are spring loaded to the hinge through the inside of the sleeves, which means they will slid into the sleeves in extension and out in flexion. Length of the sleeve should prevent the bars from dislodgement, and the cross section of both the bars and the sleeves have to correspond to each other for the sleeves to accommodate the bars within them and to prevent rotational instability within the construct itself. Summary. Applying an external fixator on the extensor surface is an idea could lead to major changes in external fixation product design, the ulno-humeral joint is taken as an example, and other joints could also be addressed taking in consideration joint size and anatomical structures at risk. The sliding technique makes the application easier, without the need to X-ray guided identification of the center of rotation

Fractures of the anteromedial facet (AO/OTA 21-B1.1, O'Driscoll Type 2, subtype 3) are associated with varus posteromedial rotational instability of the ulnohumeral joint and early post-traumatic arthritis. The purpose of this study was to examine the stability of plate (locking and non-locking) vs screw constructs in the fixation of anteromedial coronoid facet fractures in a sawbone model. An anteromedial coronoid facet fracture (AO/OTA 21-B1.1) was simulated in 24 synthetic ulna bones. They were then assigned into 3 fracture fixation groups: non-locking plate fixation, locking plate fixation, and dual cortical screw fixation. An AO 2.0 mm screw and plate system was used for the plate fixation groups and 2.0 mm cortical screws were used for the screw-only group. Following fixation, each construct was potted in bismuth alloy and secured to a servohydraulic load frame. Each construct was cycled in tension and then in compression at 0.5Hz. For both cycling modalities, an incremental loading pattern was used starting at 40 N and increased by 20 N every 200 cycles up to 200N. Fracture fragment displacement was recorded with an optical tracking system. Following cyclic loading each construct was loaded to failure (displacement >2 mm) at 10mm/min. Tension cycling – All constructs in the plated groups (locking and non-locking constructs) survived the cyclic tension loading protocol (to 200N) with maximum fragment displacement of 12.60um and 14.50um respectively. There was no statistical difference between the plated constructs at any load level. No screw-only fixed construct survived the tension protocol with mean force at failure of 110N (range 60–180N). Compression Testing – All constructs in the plated groups (locking and non-locking constructs) survived the cyclic compression loading protocol (to 200N), while all but one of the screw-only fixation constructs survived. Fracture fragment displacement was significantly greater in the screw-only repair group across all loading levels when compared to the plated constructs. There was no statistically significant difference in fragment motion between the locking and non-locking groups. Failure Testing – The maximum load at failure in the screw-only group (281.9 N) was significantly lower than locking and non-locking constructs (587.0 N and 515.5N respectively, p <0.05). There was no difference between the locking and non-locking group in mean load to failure or mean stiffness. Screw construct stiffness (337.2 N/mm) was lower than the locking and non-locking constructs (682.9 N/mm and 479.1 N/mm respectively) however this did not reach statistical significance (p=0.051). Fixation of anteromedial coronoid fractures is best achieved with a plating technique. Locking plates did not offer any advantage over conventional plates. Isolated screw fixation might not provide adequate stability for these fractures which could result in loss of reduction leading to post-traumatic arthrosis or instabilility

Introduction. Backside wear of polyethylene (PE) inlays in fixed-bearing total knee replacement (TKR) generates high number of wear debris, but is poorly studied in modern plants with improved locking mechanisms. Aim of study. Retrieval analysis of PE inlays from contemporary fixed bearing TKRs - to evaluate the relationship between backside wear and liner locking mechanism and material type and roughness of the tibial tray. Methods. MATERIAL. We included five types of implants, revised after min. 12 months (14–71): three models with a peripheral locking rim and two models with a dove-tail locking mechanism. Altogether this study included 15 inlays were removed from TKRs with CoCr alloy tray with a roughened surface and a peripheral locking lip liner (Stryker Triathlon, Ra 5,61 µm), 9 from CoCr trays with peripheral locking lip and untreated surface (Aesculap Search, Ra 0,81 µm), 13 from Ti alloy trays with peripheral locking lip and untreated surface (DePuy PFC Sigma 0,61 µm), 11 from Ti alloy trays with untreated surface and dovetail locking mechanism (Zimmer NexGen, 0,34 µm), and 9 from iplants with a Ti alloy tibial tray with mirror polished surface and dovetail locking mechanism (Smitn&Nephew Genesis II, 0,11 µm). METHODS. Wear of bearing surface and back side of retrieved inlays was examined in 10 sectors under a light microscope. Seven modes of wear were analysed and quantified according to the Hood scale: surface deformation, pitting, embedded third bodies, pitting, scratching, burnishing (polishing), abrasion and delamination. Damage of inlays caused by backside wear was also evaluated using scanning electron microscopy (SEM). Roughness of tibial tray was evaluated using a contact profilometer. Results. We found no differences between wear scores on the articulating surface in all group, they did not correlate with backside wear scores in all groups as well. Compared to all other groups, backside wear scores were significantly higher in implants with untreated Ti alloy tibial tray (P<0,001 Wilcoxon test). Lowest wear rates were found in implants from both Ti and CoCr alloys and peripheral locking rim. Interestingly there was no difference between wear of implants with polished and untreated surface (Fig. 1). SEM analysis demonstrated different wear modes in implants with dovetail mechanism and peripheral rim. The first group demonstrated signs of gross rotational instability, with severe abrasion with an arch-shaped pattern and delaminated PE (Fig 2). In one design we observed severe extrusion of PE into screw holes of the tibial tray. Inlays from trays with peripheral rim presented two types of wear: flattening of machining marks or protrusion of the material caused by the rough surface (Fig 3). Conclusions. This study demonstrates that backside wear is still a problem in modern TKR. Our findings suggest that it is predominantly affected by type of locking mechanism (with peripheral rim performing better), to a lesser extent by surface roughness of the tibial component, while material type does not seem to play an important role. This study was funded by a grant from the National Science Centre nr 2012/05/D/NZ5/01840. To view tables/figures, please contact authors directly

Background: Aim of the study was to evaluate the clinical results of Montgomery Hip Screw for fixation of proximal femoral osteotomies. There are a number of devices for proximal femoral fixation, including sliding hip screws. Rotational instability of the proximal femoral segment can be a problem. To overcome this, a hip screw has been introduced with two screws in the proximal segment. Methods and Results: A prospective cohort undergoing osteotomy was followed up. Inclusion criteria included consecutive patients < 16 years of age, with an indication for elective proximal femoral osteotomy. All operations were performed by senior author or under his supervision using a standard postero-lateral approach. Further incisions for adductor/psoas release and pelvic osteotomy were added as indicated. In 23 cases MHS was used with a mean follow up of 10 months (6 to 24). In 9 patients there was an underlying neurological problem, one case of LCPD, and the rest had DDH. Previous surgery with a hip screw on the contralateral side had been undertaken in 5 cases. The mean age was 5 years (range 1 to 12) and mean time to union was 6.3 weeks. There were no occurrences of rotational instability or failure of fixation. No wound complication was encountered in the cohort. Conclusions: Early results indicate that Montgomery Hip Screw is a safe device for fixation of proximal femoral osteotomy with the added advantage of rotational stability

The aims of this study were (1) to assess whether rotational stability testing in Gartland III supracondylar fractures can be used intra-operatively in order to assess fracture stability following fixation with lateral-entry wires and (2) to quantify the incidence of rotational instability following lateral-entry wire fixation in Gartland type III supracondylar humeral fractures in children. Twenty-one consecutive patients admitted with Grade III supracondylar fractures at the Children's Hospital at Westmead were surgically treated according to a predetermined protocol. Following closed fracture reduction, 2 lateral-entry wires were inserted under radiographic control. Stability was then assessed by comparing lateral x-ray images in internal and external rotation. If the fracture was found to be rotationally unstable by the operating surgeon, a third lateral-entry wire was inserted and images repeated. A medial wire was used only if instability was demonstrated after the insertion of three lateral wires. Rotational stability was achieved with two lateral-entry wires in 6 cases, three lateral-entry wires in 10 cases and with an additional medial wire in 5 cases. Our results were compared to a control group of 24 patients treated at our hospital prior to introduction of this protocol. No patients returned to theatre following introduction of our protocol as opposed to 6 patients in the control group. On analysis of radiographs, the protocol resulted in significantly less fracture position loss as evidenced by change in Baumann's angle (p<0.05) and lateral rotational percentage (p<0.05). We conclude that the introduction of rotational stability testing allows intra-operative assessment of fracture fixation. Supracondylar fractures that are rotationally stable intra-operatively following wire fixation are unlikely to displace post-operatively. Only a small proportion (26%) of these fractures were rotationally stable with 2 lateral-entry wires. This may be a reflection of either the fracture configuration or inability to adequately engage the medial column

Introduction: The PFNA device was developed to address problems of rotational instability in proximal femoral fractures whilst simultaneously employing a single femoral neck element. Study Design: Prospective cohort. Methods: All subtrochanteric fractures(AO31A3) admitted to the department were treated with the PFNA and specified data was recorded. Results: From April 2006 to June 2007, 62 patients were included in the study.4 month follow up has been completed in 30 patients(77% of those available).11 are awaiting follow up and 12 died.The mean age was 79.9 years. 1 patient with a short PFNA nail sustained a fracture of the femur through the site of the distal locking bolt during the follow up period and required revision. The mobility and social function scores were significantly reduced at follow up compared to pre-operative status(p=0.001).All domains of SF36 were low compared to normative data. All 30 fractures united and there was no migration, lysis around or cut out of the helical blade.In total, 46 distal locking bolts were utilised.4 of these had migrated or become loose. Conclusions: Subtrochanteric fractures in the elderly are a devastating injury. Patients do not return to pre-fracture function at 4 months post injury. Early results suggest that the PFNA appears to work well

The kinematic effect of tunnel orientation and position, during ACL reconstruction, has been only recently related to the control of rotational instability. This paper presents a detailed computer-assisted in vitro evaluation of two different femoral tunnel orientations with the same tunnel position, at 10.30 ‘o clock, during the intervention of ACL reconstruction with double bundle technique. Results highlighted better kinematic performances of the horizontal tunnel, with respect to the vertical one, in controlling antero-posterior (AP) laxities at 30°, and internal-external (IE) laxities. Elongations of anterior and posterior bundles of reconstructed ACL, for both reconstruction, decreased during PROM respectively by 20% and 40%. Total length of the graft varied during PROM, mainly due to graft elongation during tests, graft length on horizontal tunnel varied from 237 to 213mm while graft length on vertical tunnel varied from 257 to 233mm. Kinematic tests showed a better performance of horizontal tunnel in the control of IE rotations at 30° and 90° and of the Lachman test with respect to the vertical one. Stability was restored with both reconstructions

Purpose: Coronal shear fractures of the humerus include the Kocher-Lorenz fracture, an osteochondral fracture of the capitellar articular surface, the Hahn-Steinthal fracture, a substantial shear fragment, extension into the trochlea, and complete involvement of the capitellum and trochlea. If the fracture proves irreparable, it is not known what the impact of fragment excision would have on the biomechanics of the elbow. The purpose of this study was to examine the effect of the sequential loss of the capitellum and trochlea on the kinematics and stability of the elbow. Method: Eight fresh-frozen cadaveric arms were mounted in an upper extremity joint testing system, with cables attaching the tendons of the major muscles to motors and pneumatic actuators. Electromagnetic receivers attached to the radius and ulna enabled quantification of the kinematics of both bones with respect to the humerus. The distal humeral articular surface was sequentially excised to replicate clinically relevant coronal shear fractures while leaving the collateral ligaments intact. Active flexion in both the vertical and valgus-loaded positions, and passive rotation in the vertical position was conducted for each excision. Results: Excision of the capitellum had no effect on ulnohumeral stability or kinematics in both the vertical or valgus positions (p=1.0). Excision of the entire capitellum and trochlea led to significant valgus instability with the arm in the valgus position (p=0.01), while excision of the lateral trochlea led to increased valgus instability with pronated flexion in the valgus position (p=0.049). Progressive loss of the articular surface led to posterior, inferior, and medial displacement of the radial head with respect to the capitellum and increased external rotation of the ulna with respect to the humerus in the vertical position (p< 0.05). Conclusion: Excision of the capitellum did not result in valgus or rotational instability, while excision of the trochlea resulted in multiplanar instability. The radial head displaced medially because it is constrained to the ulna by the annular ligament, and the ulna pivoted into valgus and external rotation on the residual trochlea and medial collateral ligament. In patients with coronal shear fractures, the trochlea must be reconstructed to prevent instability and the potential for secondary degenerative change

Introduction: The clinical results of the modular Charnley Elite total hip system have been the subject of some interest in recent years. Some studies have shown significant subsidence and rotational instability in some stems when used with low-viscosity cement. These unstable stems have been shown to fail early. This purpose of this study is to demonstrate our conflicting clinical results. Materials and Methods: 616 modular Charnley Elite total hip arthroplasties were inserted between 1995 and 2002 at Wrightington Hospital, which is a tertiary referral centre and centre of excellence for joint replacement in United Kingdom. Both Consultants and trainees performed operations and a variety of surgical approaches were used. Normal viscosity bone cement was used in all patients. All patients were followed up prospectively. Results: At mean follow-up of 8 years (range 5–12), 471 hips were available for review. 87 patients had died and 12 were lost to follow-up. 2.7% (13 cases) of femoral components and 2.9% (14 cases) of acetabular components had been revised for aseptic loosening. 10 hips (2.1%) underwent revision for deep infection and 2 (0.04%) for recurrent dislocation. The overall survival with aseptic loosening as an end point was 97% and for revision for any reason was 94.5%. Conclusion: Our results show acceptable clinical survivor-ship for this implant when used with standard viscosity cement. This contrasts with the lower survivorship rates published by other centres. Our result should reassure patients and surgeons alike that this prosthesis can be associated with acceptable results in the medium term

Purpose: The treatment of extension type II pediatric supracondylar humerus fractures remains controversial. Some argue that closed reduction and cast immobilization is sufficient to treat these fractures, while others advocate closed reduction and pinning. The purpose of this radiographic outcomes study was to determine whether closed reduction and cast immobilization could successfully obtain and maintain appropriate position of extension type II supracondylar humerus fractures. Method: The radiographs of 1017 pediatric patients treated for supracondylar fractures between 1987 and 2007 were retrospectively reviewed. Pre-reduction, immediate post-reduction, and final radiographs of 155 extension type II fractures were measured in order to assess the position and alignment of the fracture fragments. Measurements included the anterior humeral line, humeral-capitellar angle, Baumann’s angle, the Gordon index, and the Griffet index. The latter two indices calculate the rotational instability of the fracture, which can be predictive of reduction loss. Patients were excluded if insufficient radiographs failed to allow complete assessment of the measurement parameters, or if open reduction was required. Results: The average age of the subjects was 5.3 years (range 1–13 years) and had a mean follow-up of 5.3 months. Analysis of the final radiographs demonstrated that in 80% of subjects, the anterior humeral line remained anterior to the mid third segment of the capitellum (radiographic extension deformity), the mean humeral-capitellar angle was 23.8° (range – 11°–50°), the mean Baumann’s angle was 79.4° (range 62°–97°), the mean Gordon index was 4.59%, and 44% of subjects had a Griffet index between 1–3 (potentially indicative of unstable reduction due to malrotation of the fragments, which can allow the development of a cubitus varus deformity). Conclusion: From this radiographic review, a significant proportion of fractures treated with closed reduction and cast immobilization failed to achieve anatomic position and alignment on final x-rays. However, the clinical significance of these results and the potential for long-term re-modeling of these fractures remains unknown

Introduction: The clinical results of the modular Charnley Elite total hip system have been the subject of some interest in recent years. Some studies have shown significant subsidence and rotational instability in stems when used with low-viscosity cement. These unstable stems have been shown to fail early. The purpose of this study is to demonstrate our conflicting clinical results. Materials and Methods: 616 modular Charnley Elite total hip arthroplasties were inserted between 1995 and 2002 at Wrightington Hospital, which is a tertiary referral centre and centre of excellence for joint replacement in United Kingdom. Both Consultants and trainees performed operations and a variety of surgical approaches were used. Normal viscosity bone cement was used in all patients. All patients were followed up prospectively. Results: At mean follow-up of 8 years (range 5–12), 471 hips were available for review. 87 patients had died and 12 were lost to follow-up. 2.7% (13 cases) of femoral components and 2.9% (14 cases) of acetabular components had been revised for aseptic loosening. 10 hips (2.1%) underwent revision for deep infection and 2 (0.04%) for recurrent dislocation. The overall survival with aseptic loosening as an end point was 97% and for revision for any reason was 94.5%. Conclusion: Our results show acceptable clinical survivor-ship for this implant when used with standard viscosity cement. This contrasts with the lower survivorship rates published by other centres. Our result should reassure patients and surgeons alike that this prosthesis can be associated with acceptable results in the medium term

Problem: Surgical technique and short term results of ligament reconstruction with trizeps tendon graft in posterolateral rotational instability of the elbow. Methods: From 2003 to 2006 posterolateral ligament reconstruction with a single strand trizeps tendon graft was performed in 38 patients with posterolateral instability of the elbow, mainly associated with refractory lateral epicondylitis. The reconstructions were performed with the original O Driscoll technique (6), interference screw fixation (30) and transfixation screw (2). There were no neurological complications, one superficial wound infection resolved by revision and 3 arthroscopic revisions for intraarticular scaring. The first 21 operated patients with a minimum follow up of twelve months were reviewed with a subjective 100 point rating score. Results: From 21 patients 4 could not be reached by letter or telephone, 2 patients were excluded for pre-operative stiffness and previous operations other than extensor release. 15 patients could be evaluated. Average follow up was 15,1, min 12, max 24 months. Patients satisfaction with the operation was rated very good by 6 patients (40%), good by 5 (33,3%) unchanged by 4 (26,7 %), none worsened. Mean postoperative score was 83/100 points. Mean score for pain was 22,2/30, for ADL 7,3/8, sleep 1,9/2, range of arm motion 9,2/10, extension 9,2/10, flexion 4,6/5, supination 4,7/5, pronation 4,2/5 and strength 20,1/25 points. Conclusion: Single strand posterolateral ligament reconstruction with a trizeps tendon graft in posterolateral instability of the elbow shows reliable short term results. More secure fixation is achieved with bone tunnel fixation and tenodesis or transfixation

Purpose: The role of the posterior bundle of the medial collateral ligament (PMCL) in stability of the elbow remains poorly defined. The purpose of this study was to determine the effect of sectioning the PMCL on the stability of the elbow. Method: Varus and valgus gravity-loaded passive elbow motion and simulated active vertical elbow motion were performed on 11 cadaveric arms. An in-vitro elbow motion simulator, utilizing computer-controlled pneumatic actuators and servo-motors sutured to tendons, was used to simulate active elbow flexion. Varus/valgus angle and internal/external rotation of the ulna with respect to the humerus were recorded using an electromagnetic tracking system. Testing was performed on the intact elbow and following sectioning of the PMCL. Results: With active flexion in the vertical position the varus/valgus kinematics were unchanged after PMCL sectioning (p=0.08). However, with the forearm in pronation, there was a significant increase in internal rotation after PMCL sectioning compared to the intact elbow (p< 0.05) which was most evident at 0° and 120° degrees of flexion (p< 0.05). This rotational difference was not statistically significant with the forearm in supination (p=0.07). During supinated passive flexion in the varus position, PMCL sectioning resulted in increased varus angulation at all flexion angles (p< 0.05). In pronation varus angulation was only increased at 120° of flexion (p< 0.05). However, internal rotation was increased at flexion angles of 30° to 120° (p< 0.05). In supination, sectioning the PMCL had no significant effect on maximum varus-valgus laxity or maximum internal rotation (p=0.1). However, in pronation, the maximum varus-valgus laxity increased by 3.5° (30%) and maximum internal rotation increased by 1.0° (29%) (p< 0.05). Conclusion: These results indicate that isolated sectioning of the PMCL causes a small increase in varus angulation and internal rotation during both passive varus and active vertical flexion. This study suggests that isolated sectioning of the PMCL may not be completely benign and may contribute to varus and rotation instability of the elbow. In patients with insufficiency of the PMCL appropriate rehabilitation protocols (avoiding forearm pronation and shoulder abduction) should be followed when other injuries permit