The function of the knee joint is to allow for locomotion and is comprised of various bodily structures including the four major ligaments; medial collateral ligament (MCL), lateral collateral ligament (LCL), anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL). The primary function of the ligaments are to provide stability to the joint. The knee is prone to injury as a result of osteoarthritis as well as ligamentous and meniscal lesions. Furthermore, compromised joint integrity due to ligamentous injury may be a result of direct and indirect trauma, illness, occupational hazard as well as lifestyle. A device capable of non-invasively determining the condition of the ligaments in the knee joint would be a useful tool to assist the clinician in making a more informed diagnosis and prognosis of the injury. Furthermore, the device would potentially reduce the probability of a misdiagnosis, timely diagnosis and avoidable surgeries. The existing Laxmeter prototype (UK IPN: GB2520046) is a Stress Radiography Device currently limited to measuring the laxity of the MCL and LCL at multiple fixed degrees of knee flexion. Laxity refers to the measure of a ligament's elasticity and stiffness i.e. the condition of the ligament, by applying a known load (200N) to various aspects of the proximal tibial and thereby inducing tibial translation. The extent of translation would indicate the condition of the ligament. The Laxmeter does not feature a load applying component as of yet, however, it allows for the patient to be in the most comfortable and ideal position during radiographic laxity measurement testing. The entire structure is radiolucent and attempts to address the limitations of existing laxity measurement devices, which includes: excessive radiation exposure to the radiographic assistant, little consideration for patient ergonomics and restrictions to cruciate or collateral ligament laxity measurements. The study focusses on further developing and modifying the Laxmeter to allow for: the laxity measurement of all four major ligaments of the knee joint, foldability for improved storage and increased structural integrity. Additionally, a load applicator has been designed as an add-on to the system thereby making the Laxmeter a complete Stress Radiography Device. Various materials including Nylon, Polycarbonate, Ultra High Molecular Weight Polyethylene (UHMWPE) – PE 1000, and Acetal/ POM were tested, using the Low Dose X-ray (Lodox) scanner, to determine their radiolucency. All materials were found to be radiolucent enough for the manufacture of the Laxmeter structure as well as the load applicator in order to identify and measure the translation of the tibia with respect to the stationary femur. The Laxmeter allows for the measurement of the laxity of the MCL and LCL at multiple fixed degrees of flexion by providing the ideal patient position for testing. The next iteration of the device will present an affordable and complete Stress Radiography Device capable of measuring the laxity of all four major ligaments of the knee joint at multiple fixed degrees of flexion. Future work would include aesthetic considerations as well as an investigation into carbon-fibre-reinforced plastics

Assessment of stability in ankle fractures is key in deciding the most appropriate mode of treatment. Stress radiographs have been suggested as a potential method for assessing ankle stability in patients with apparently isolated lateral malleolar fractures. Whilst stress radiographs have been found to be both sensitive and specific in cadaveric experiments, recent clinical studies have suggested that a widened medial clear space (MCS) on stress radiographs may not equate to a functionally unstable ankle. We aimed to assess whether patients with an apparently isolated lateral malleolar fracture on presentation but with a positive gravity stress radiograph (GSR) could be successfully managed non-operatively.

A prospective study of all patients with lateral malleolar fractures presenting to our orthopaedic trauma department was undertaken. Patients with an oblique distal fibular fracture pattern and no obvious MCS widening on routine radiographs underwent a GSR. Measurements of the radiographic MCS and superior clear space (SCS) were made and compared with published criteria.

155 patients were included in the study and treated non-operatively fully weight bearing in either a cast or removable boot. Following fracture union all patients had both anatomical alignment of the ankle mortise and good or excellent function. The MCS of 79% of these patients was found to be greater than 4 mm with 19% greater than 6 mm. All of these patients were successfully managed non-operatively.

The currently used criteria for measurements on stress radiographs result in high numbers of false positive cases. This may be leading to unnecessary surgery. Further investigation is required in order to identify other clinical or radiographic criteria that may be of use in the assessment of functional ankle stability after fracture.

Objectives. To evaluate the applicability of MRI for the quantitative assessment of anterior talofibular ligaments (ATFLs) in symptomatic chronic ankle instability (CAI). Methods. Between 1997 and 2010, 39 patients with symptomatic CAI underwent surgical treatment (22 male, 17 female, mean age 25.4 years (15 to 40)). In all patients, the maximum diameters of the ATFLs were measured on pre-operative T2-weighted MR images in planes parallel to the path of the ATFL. They were classified into three groups based on a previously published method with modifications: ‘normal’, diameter = 1.0 - 3.2 mm; ‘thickened’, diameter > 3.2 mm; ‘thin or absent’, diameter < 1.0 mm. Stress radiography was performed with the maximum manual force in inversion under general anaesthesia immediately prior to surgery. In surgery, ATFLs were macroscopically divided into two categories: ‘thickened’, an obvious thickened ligament and ‘thin or absent’. The imaging results were compared with the macroscopic results that are considered to be of a gold standard. Results. Agreement was reached when comparison was made between groups, based on MRI and macroscopic findings. ATFLs were abnormal in all 39 cases and classified as ten ‘thickened’ and 29 ‘thin or absent’. As to talar tilt stress radiography, a clear cut-off angle, which would allow discrimination between ‘thickened’ and ‘thin or absent’ patients, was not identified. Conclusion. MRI is valuable as a pre-operative assessment tool that can provide the quantitative information of ATFLs in patients with CAI. Cite this article Bone Joint Res 2014;3:241–5

Abstract. Introduction. Patient selection is key to the success of medial unicondylar knee arthroplasty (UKA). Progression of arthritis is the most common indication for revision. Various methods of assessing the lateral compartment have been used including stress radiography, radioisotope bone scanning, MRI, and visualisation at the time of surgery. Arthroscopy is another means of assessing the integrity of the lateral compartment. Methods. We used per-operative arthroscopy as a means to confirm suitability for UKA in a consecutive series of 279 Oxford medial UKA. This study reports the long-term results of a previously published cohort of knees. Our series of UKA with per-operative arthroscopy (Group 1) was compared to all Oxford UKA (Group 2) and all UKA in the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR) (Group 3). Results. The 14-year cumulative percentage revision (CPR) was 18.5% (95% CI 12.7, 26.4) for group 1, 19.7% (95% CI 18.8, 20.6) for group 2, and 19.2% (95% CI 18.5, 19.8) for group 3. There was no statistically significant difference in the (CPR) for the entire period when group 1 was compared to groups 2 or 3. Progression of arthritis was the indication for revision in similar proportions for the three groups (Group 1: 32.3%, Group 2: 35.7% and Group 3: 33.5%). Following per-operative arthroscopy 21.6% (77/356) of knees underwent a change of surgical plan from UKA to TKA. Conclusion. Per-operative arthroscopy may improve medium-term medial unicompartmental knee survivorship but does not improve long-term survivorship nor reduce revision due to progression of arthritis

Joint laxity assessments have been a valuable resource in order to understand the biomechanics and pathologies of the knee. Clinical laxity tests like the Lachman test, Pivot-shift test and Drawer test are, however, subjective of nature and will often only provide basic information of the joint. Stress radiography is another option for assessing knee laxity; however, this method is also limited in terms of quantifiability and one-dimensionality. This study proposes a novel non-invasive low-dose radiation method to accurately measure knee joint laxity in 3D. A method that combines a force controlled parallel manipulator device, a medical image and a biplanar x-ray system. As proof-of-concept, a cadaveric knee was CT scanned and subsequently mounted at 30 degrees of flexion in the device and placed inside a biplanar x-ray scanner. Biplanar x-rays were obtained for eleven static load cases. The preliminary results from this study display that the device is capable of measuring primary knee laxity kinematics similar to what have been reported in previous studies. Additionally, the results also display that the method is capable of capturing coupled motions like internal/external rotation when anteroposterior loads are applied. We have displayed that the presented method is capable of obtaining knee joint laxity in 3D. The method is combining concepts from robotic arthrometry and stress radiography into one unified solution that potentially enables unprecedented 3D joint laxity measurements non-invasively. The method potentially eliminates limitations present in previous methods and significantly reduces the radiation exposure of the patient compared to conventional stress radiography

Background: Stress radiography and more recently magnetic resonance imaging have been used to study the integrity of lateral ankle ligaments in chronic symptomatic instability after injury. Aim: Our aim was to see if magnetic resonance imaging was as good as examination under anaesthesia and stress radiography, for diagnosing injury to the lateral ankle ligaments. Study Design: Cross-over study. Methods: Fifty eight patients, 47 men and 11 women, were included in the study. These were athletes or military personnel with symptomatic instability of the ankle after injury. This cohort of patients had MRI scans, stress radiographs and arthroscopic treatment of their ankle. Integrity of the calcaneo-fibular ligament (CFL) was recorded arthroscopically. The sensitivity, specificity, positive and negative predictive value of MRI and stress views, in assessing integrity of the CFL, were compared against the arthroscopic findings which was considered to be the gold standard. Results: Stress radiography under anaesthesia and MRI has sensitivities of 94% and 47% and specificities of 98% and 83% for diagnosing injury to the CFL, respectively. Stress radiography has a higher accuracy in diagnosing CFL injuries as compared to MRI. Conclusion: The results of this study casts doubt on the efficacy of MRI in the diagnosis of serious ankle ligament injuries

Introduction: Ankle inversion injuries are common, with an incidence of 1 per day per 10,000 of the population. Chronic instability is a frequent sequela, and has been estimated to occur after approximately 10 to 20% patients, regardless of the type of initial treatment. Magnetic Resonance Imaging (MRI) has become a routine diagnostic tool in investigating knee injuries, but little has been published concerning ankle injuries and ankle instability. Aim: To compare the efficacy of conventional magnetic resonance (MR) imaging and stress radiography in the detection of lateral collateral ligament abnormalities in patients with chronic ankle instability. Materials and Methods: All patients presenting to the senior author’s OPD with clinical impression of ankle instability were investigated prospectively using MRI and stress x-rays (Telos). These films were officially reported and then, these reports were subsequently reviewed post-anatomical reconstruction. Results: Over a two-year period, 18 patients underwent anatomical reconstruction using the modified Brostrom technique. MRI identified a tear of the anterior talofibular (AFT) ligament in 12 (66%) patients, and the calcaneofibular (CF) ligament was torn in 9 (50%) patients. Stress radiography identified instability of 14 of the 18 (77%) patients. Stress radiography identified instability of 14 of the 18 (77%) patients. Surgical exploration revealed either attenuation or rupture of either the AFT and/or CF ligaments in all 18 patients. MRI demonstrated concomitant injuries to the ankle and subtalar joints, including peroneal tenosynovitis (76%), anterolateral impingement syndrome (66%) and attenuated peroneal retinaculum (55%). Conclusion: Ankle instability may be more reliably demonstrated using stress x-rays than MRI: however, lowfield MRI is a very useful diagnostic tool in the study of concomitant ankle injuries and we would suggest that both modalities be considered, especially if surgical intervention is anticipated

Introduction. Modified gap technique has been reported to be beneficial for the intraoperative soft tissue balancing in posterior-stabilized (PS) -TKA. We have found intraoperative ligament balance changed depending on joint distraction force, which might be controlled according to surgeons' fells. We have developed a new surgical concept named as “medial preserving gap technique (MPGT)” to preserve medial knee stability and provide quantitative surgical technique according to soft tissue balance measurement using a tensor device. The purpose of this study was to compare 3-years postoperative knee stability after PS-TKA in varus type osteoarthritic (OA) knees between MPGT and measured resection technique (MRT). Material & Method. The subjects were 94 patients underwent primary unilateral PS-TKA for varus type OA knees. The surgical technique was MPGT in 47 patients and MRT in 47 patients. An originally developed off-set type tensor device was used to evaluate intraoperative soft tissue balance. In MPGT, medial release was limited until the spacer block corresponding to the bone thickness from proximal lateral tibial plateau could be easily inserted. Femoral component size and external rotation angle were adjusted depending on the differences of center gaps and varus angles between extension and flexion before posterior femoral condylar resection. The knee stabilities at extension and flexion were assessed by stress radiographies at 1 and 3 years after TKA; varus-valgus stress test at extension and stress epicondylar view at flexion. We measured medial and lateral joint openings (MJO, LJO) at both knee extension and flexion. MJOs and LJOs at 2 time periods were compared in each group using paired t-test. Each joint opening distance was compared between 2 groups using unpaired t-test. The significance level was set as P < 0.05. Results. The mean extension MJOs at 1 and 3 years after TKA were 2.4, 2.6 mm in MPGT and 3.2, 3.1 mm in MRT respectively. The mean extension LJOs were 3.5, 3.5 mm in MPGT and 4.6, 4.5 mm in MRT. The mean flexion MJOs were 0.95, 0.77 mm in MPGT and 1.5, 1.2 mm in MRT, and the mean flexion LJOs were 2.2, 2.1 mm in MPGT and 3.0, 2.7 mm in MRT. MJOs were significantly smaller than LJOs in each group at 2 time periods. MJOs at extension and flexion, and LJOs at extension were significantly smaller in MPGT than MRT at 2 time periods. Discussion. Medial knee stabilities had been reported to be essential for postoperative clinical results. We reported medial compartment gap was more stable during mid-to-deep knee flexion in MPGT than MRT. MPGT provided the more stable intraoperative soft tissue balance than MRT in PS-TKA. MPGT was useful to preserve the higher medial knee stability than the lateral as well as MRT, and beneficial to enhance postoperative knee stabilities as long as 3-years after PS-TKA in varus OA knees. MPGT would be an objective and safer gap technique to enhance clinical outcomes

Aims

Complete ruptures of the ulnar collateral ligament (UCL) of the thumb are a common injury, yet little is known about their current management in the UK. The objective of this study was to assess the way complete UCL ruptures are managed in the UK.

Introduction. Both measured resection technique and gap balancing technique have been important surgical concepts in total knee arthroplasty (TKA). Modified gap technique has been reported to be beneficial for the intra-operative soft tissue balancing in posterior-stabilizing (PS) -TKA. On the other hand, we have found joint distraction force changed soft tissue balance measurement and medial knee instability would be more likely with aiming at perfect ligament balance at extension in modified gap technique. The medial knee stability after TKA was reported to essential for post-operative clinical result. We have developed a new surgical concept named as “medial preserving gap technique” for varus type osteoarthritic (OA) knees to preserve medial knee stability and provide quantitative surgical technique using tensor device. The purpose of this study was to compare post-operative knee stability between medial preserving gap technique (MPGT) and measured resection technique (MRT) in PS-TKA. Material & Method. The subjects were 140 patients underwent primary unilateral PS-TKA for varus type OA knees. The surgical technique was MPGT in 70 patients and MRT in 70 patients. There were no significant differences between two groups in the pre-operative clinical features including age, sex, ROM and deformity. Originally developed off-set type tensor device was used to evaluate both center gap and varus angle with 40 lbs. of joint distraction force. The extension gap preparation was identical in both group. In MPGT group, femoral component size and external rotation angle were adjusted depending on the differences of center gaps and varus angles between extension and flexion before posterior femoral condylar osteotomy. The knee stabilities at extension and flexion were assessed by stress radiographies; varus-valgus stress test with extension and stress epicondylar view with flexion, at one-month and one-year after TKA. We measured joint opening distance (mm) at medial and lateral compartment at both knee extension and flexion. Joint opening distances were compared between two groups using unpaired t-test, and the difference between medial and lateral compartment in each group was compared using paired t- test (p<0.05). Results. Joint opening distances at medial compartments with both extension and flexion were significantly smaller than lateral in both groups. There were no significant differences in join opening distance between two groups at medial compartment, but those at lateral were significantly smaller in MPGT than MRT with both knee extension and flexion. Discussion. In the present study, we found MPGT resulted in equal postoperative medial knee stability as in MRT, and superior to MRT as for the lateral knee stability. This finding would be the result of different femoral external rotation angle and femoral component size selection between two groups. We used the difference of varus angle and center gap between flexion and extension for the femoral component size selection and external rotation angle in MPGT. Quantitative surgical concept; MPGT, was found to be safer and feasible gap technique in PS-TKA to preserving medial knee stability and control lateral laxity in varus type OA knee. MPGT would be an advantageous gap technique to enhance clinical outcome

Background. In recent literatures, medial instability after TKA was reported to deteriorate early postoperative pain relief and have negative effects on functional outcome. Furthermore, lateral laxity of the knee is physiological, necessary for medial pivot knee kinematics, and important for postoperative knee flexion angle after cruciate-retaining total knee arthroplasty (CR-TKA). However, the influences of knee stability and laxity on postoperative patient satisfaction after CR-TKA are not clearly described. We hypothesized that postoperative knee stability and ligament balance affected patient satisfaction after CR-TKA. In this study, we investigated the effect of early postoperative ligament balance at extension on one-year postoperative patient satisfaction and ambulatory function in CR-TKAs. Materials & Methods. Sixty patients with varus osteoarthritis (OA) of the knee underwent CR-TKAs were included in this study. The mean age was 73.6 years old. Preoperative average varus deformity (HKA angle) was 12.5 degrees with long leg standing radiographs. The knee stability and laxity at extension were assessed by stress radiographies; varus-valgus stress X-ray at one-month after operation. We measured joint separation distance (mm) at medial compartment with valgus stress as medial joint opening (MJO), and distance at lateral compartment with varus stress as lateral joint opening (LJO) at knee extension position. To analyze ligament balance; relative lateral laxity comparing to the medial, varus angle was calculated. New Knee Society Score (NKSS) was used to evaluate the patient satisfaction at one-year after TKA. We measured basic ambulatory functions using 3m timed up and go test (TUG) at one-year after surgery. The influences of stability and laxity parameters (MJO, LJO and varus angle at extension) on one-year patient satisfaction and ambulatory function (TUG) was analyzed using single linear regression analysis (p<0.01). Results. MJOs at knee extension one-month after TKA negatively correlated to patient satisfaction (r=−0.37, p<0.01) and positively correlated to TUG time (r=0.38, p<0.01). LJOs at knee extension had no statistically significant correlations to patient satisfaction and TUG. The extension varus angle had significant positive correlation with patient satisfaction (r=0.40, p<0.01). Discussions. In our study, we have found significant correlations of the early postoperative MJOs at extension to postoperative patient satisfaction and TUG one-year after CR-TKA. Our results suggested that early postoperative medial knee stabilities at extension were important for one-year postoperative patient satisfaction and ambulatory function in CR-TKA. Other interest finding was that postoperative patient satisfaction was positively correlated with extension varus angle. This finding suggested that varus ligament balance; relative lateral laxity to medial stability, was beneficial for postoperative patient satisfaction after CR-TKA. Intra-operative soft tissue balance had been reported to significantly affect postoperative knee stabilities. Therefore, with our findings, surgeons might be better to manage intra-operative soft tissue balance to preserve medial stability at extension with permitting lateral laxity, which would enhance patient satisfaction and ambulatory function after CR-TKA for varus type OA knee. Conclusion. Early postoperative medial knee stability and relative lateral laxity would be beneficial for patient satisfaction and function after CR-TKA

Objective. As the aging society progresses rapidly in Japan, the number of elderly patients underwent TKA is increasing. These elderly patients do not expect to do sports, but regain independency in the activity of daily living. Therefore, we measured basic ambulatory function quantitatively using 3m timed up and go (TUG) test. We clinically experienced patient with medially unstable knee after TKA was more likely to result in the unsatisfactory outcome. We hypothesized that post-operative knee stability influenced ambulatory function recovery after TKA. In this study, we evaluated ambulatory function and knee stability quantitatively, and analyzed the effect of knee stability on the ambulatory function recovery after TKA. Materials & Methods. Seventy nine patients with varus type osteoarthritic knees underwent TKA were subjected to this study. The mean age of surgery was 72.4 years old. Preoperative standing coronal deformity was 9.6 degrees in varus. TUG test results in less duration with faster ambulatory function. TUG (seconds) was measured at 3 time periods; pre-operatively, at hospital discharge and 1year after surgery. To standardize TUG recovery time during 1 year after TKA, we defined TUG recovery rate as the percentage of recovery time to the pre-operative TUG as shown in the following equation. TUG recovery rate (%) = (TUG pre-op –TUG 1y po) / TUG pre-op ×100. We also evaluated the knee stability at hospital discharge and 1year after surgery. The knee stability at extension and flexion were assessed by varus and valgus stress radiography using Telos (10kg) and stress epicondylar view with 1.5kg weight at the ankle respectively. Image analyzing software was used to measure joint separation distance (mm) at medial as medial joint opening (MJO) and at lateral as lateral joint opening (LJO) at both knee extension and flexion. (Fig.1). The sequential change of TUG was analyzed using repeated measures ANOVA (p<0.05). The influence of joint opening distances (MJO and LJO at extension and flexion) on TUG 1y po and TUG recovery rate were analyzed using simple linear regression analysis (p<0.05). Results. The mean TUGs were 13.4, 13.7 and 10.8 seconds pre-operatively, at hospital discharge and 1 year after TKA respectively. Significant decrease was found at 1 year after surgery. TUG pre-op did not show significant correlation to any joint openings. TUG 1y po was positively correlated with both flexion and extension MJO at hospital discharge. (Fig.2) TUG recovery rate negatively correlated to flexion-MJO at hospital discharge. (Fig.3). Discussions. The most interesting findings in the present study were that both flexion and extension MJO at hospital discharge were positively correlated with TUG 1y po and negatively correlated with TUG recovery rate. This indicated that early post-operative medial stability played an important role in the recovery of ambulatory function. The early post-operative medial instability would cause pain and deteriorate functional recovery after surgery. There is some disagreement regarding the importance of pursuing the perfect ligament balance, which would be more likely to result in medial instability. Consequently, surgeons should prioritize medial stability for better ambulatory functional recovery after TKA

Introduction. To achieve well aligned and balanced knee is essential for the post-operative outcome in total knee arthroplasty (TKA). Gap balancing technique can adjust the bone cut depending on the soft tissue balance in addition to soft tissue releases. Therefore, gap balancing technique would be more advantageous in soft tissue balance comparing to measured resection technique (MRT) in which soft tissue balancing relayed on soft tissue releases alone. Nevertheless, the influence of surgical technique on the post-operative knee stability has not been fully investigated. Objective. We introduced a new surgical technique (medial gap technique: MGT) according to modified gap technique regarding medial knee stability as important. The intra-operative soft tissue balance and post-operative knee stability were compared between MGT and MRT in posterior-stabilized (PS) TKA for varus type osteoarthritic knees. Materials & Methods. Sixty varus type osteoarthritis knees were involved in this study. PS type TKAs (NexGen LPS flexR) were performed using MGT in 30 knees (MGT group) and MRT in 30 knees (MRT group). The extension gap was made in the same manners in both groups. Both femoral and tibial bone cuts were perpendicular to the mechanical axis. Medial soft tissue releases were limited until the spacer block with the thickness corresponding to the resected lateral tibial condyle could be inserted. After extension gap was prepared, OFR-tensorR was used to assess soft tissue balance (center gap, varus angle) at extension and flexion prior to posterior femoral condyle bone resection. Both differences of the center gap and varus angle between at extension and flexion were calculated and used for size selection and external rotation angle of femoral component in MGT. The final joint component gaps were evaluated using OFR-tensorR with both femoral trial in place and patello-femoral joint reduced at 0, 10, 30, 45, 60, 90, 120 and 135 degrees of flexion. Quantitative stress radiographies were performed at 1 month, 6 months and 1 year post-operatively to assess joint stability. Joint opening distance (mm) at both medial and lateral joint compartment were measured with knee extension and flexion. Each parameter was compared between MGT and MRT group using unpaired t-test (p<0.05). Results. Pre-operative factors showed no significant differences between 2 groups. The joint component gaps were significantly larger in MRT group from 45 to 135 degrees of flexion (Fig.1). The joint opening at the lateral compartment was significantly larger than medial at both knee extension and flexion in both groups. The joint openings were significantly larger bilaterally in MRT group comparing to MGT group at both extension and flexion (Fig.2, 3). Discussions. Medial instability has been reported as a possible reason for the persistent knee pain after TKA in the varus knees. We proposed a new surgical technique (MGT) not to deteriorate medial stability and allow lateral looseness in TKA. Post-operative knee stability was superior in MGT group comparing to MRT group from one month to one year after surgery. The difference of the intra-operative soft tissue balance might play an important role on the post-operative knee stability

Objective. The goal of total knee arthroplasty (TKA) is to achieve a stable and well-aligned tibiofemoral and patello-femoral (PF) joint, aiming at long-term clinical patient satisfaction. The surgical principles of both cruciate retaining (CR) and posterior stabilized (PS) TKA are accurate osteotomy and proper soft tissue balancing. We have developed an offset-type tensor, and measured intra-operative soft tissue balance under more physiological joint conditions with femoral component in place and reduced PF joint. In this study, we measured intra-operative soft tissue balance and assessed the post-operative knee joint stability quantitatively at one month, six months and one year after surgery, and compared these parameters between CR and PS TKAs. Material and Method. Sixty patients with varus osteoarthritis of the knee underwent TKAs (30 CR TKAs: CR and 30 PS TKAs: PS). Mean varus deformity in standing position was 11.1 degrees in CR, and 12.6 degrees in PS. All TKAs were performed by a single surgeon with measured resection technique. The external rotation of posterior femoral condyle osteotomy was performed according to surgical epicondylar axis in pre-operative CT. We measured intra-operative soft tissue balance using an offset-type tensor with 40 lbs of joint distraction force at 0, 10, 30, 45, 60, 90, 120 and 135 degrees of flexion. The joint component gap (mm) and varus angle (degrees) were measured at each flexion angles. One month, six months and one year after surgery, we evaluated the knee stability at extension by varus and valgus stress radiography using Telos (10kg) and at flexion by epicondylar view with 1.5kg weight at the ankle. We measured joint separation distance at medial as medial joint looseness (MJL) and at lateral as lateral joint looseness (LJL). Intra-operative measurements and post-operative joint stabilities were compared between CR and PS using unpaired t-test. The change of joint looseness in each group was analyzed using repeated measures ANOVA. Result. Joint gap kinematics was different between CR and PS (Fig. 1). Joint component gap in PS were significantly higher than CR from 30 to 120 degrees of flexion. Post-operative MJL and LJL changes are shown in figure 2 with knee extension, and in figure 3 with knee flexion. PS showed significantly higher joint looseness than CR at both extension and flexion at three time periods after surgery. There were no significant post-operative changes in both MJL and LJL in CR and PS TKAs. Discussion. We found significant differences in gap kinematics and also in the one year post-operative joint stability between CR and PS. The different characteristics of the intra-operative soft tissue balance between CR and PS TKAs would be a possible reason for the differences in the post-operative knee stability. Our results suggested that TKAs performed by measured resection technique have significantly higher joint stability with CR TKAs comparing to PS TKAs. These findings would be important issues in choosing prosthesis and surgical technique. Conclusion. With measured resection technique, CR TKAs had more consistent joint gap kinematics and higher joint stability after surgery comparing to PS TKAs

Aims: In this prospective study, we determined whether corrective surgery for rotational malalignment of femoral prosthesis components would benefit patients that had previously undergone total knee arthroplasty. Methods: 68 consecutive patients with a painful total knee arthroplasty were screened with computed tomography. All patients were offered plain radiographs, tangential radiographs and stress radiography for valgus/varus stability in 20° and 90° flexion. No patient had signs of infection or loosening. 14 patients were selected that had isolated internal malrotation of the femoral component. No other malpositions could be found. Two patients with mild (≤3°) internal mal-rotation were excluded due to conservative treatment. Revision surgery was performed to replace prosthetic components in 12 patients with internal malrotation ≥ 4° within 3 years of the primary arthroplasty. Results: The corrective surgery resulted in an increase in the average Knee Society Score from 51/65 to 86/86 points and an improvement in the average Hospital for Special Surgery knee score from 64 to 83 points. The mean follow-up was 57 (range 46 to 89) months. Conclusion: This study showed that correction of isolated internal malrotation of the femoral component will lead to better clinical and functional outcomes

Aim: To describe a new radiological sign after rupture of the thumb ulnar collateral ligament. Introduction: Rupture of the thumb ulnar collateral ligament is a commonly missed injury, with delayed diagnosis leading to considerable morbidity. Stress radiographs and MRI scans have been used to diagnose chronic (gamekeepers thumb) or acute (skiers thumb) injuries to this ligament. The former often causes discomfort and the latter are often not readily available. We describe a new radiological sign seen on the lateral radiographs of the thumb, which has previously not been described in the literature. The ‘sag sign’ is volar subluxation of the proximal phalanx in relation to the metacarpal at the metacarpal phalangeal joint. Method: Between 2001–2006, radiographs of nineteen patients who had undergone repair of thumb ulnar collateral ligaments were retrospectively reviewed. There were 12 male and 7 female patients with an average age of 44. These were compared to a control group of normal thumb radiographs. The ‘sag sign’ was present on all the lateral radiographs of thumbs with ulnar collateral ligament tears. Once the ligament was repaired, the metacarpophalangeal joint alignment returned to normal. The sign was validated by senior house officers and registrars in orthopaedics training. Conclusion: The sag sign is a reliable indicator of an underlying injury to the thumb ulnar collateral ligament. Many studies have looked at the radiological diagnosis of this commonly missed injury. Stress radiography and ultrasound require straining an injured thumb which can extend the lesion and cause discomfort. MRI and MR arthrography are both sensitive and specific, but are costly and time consuming. Our sign is evident on plain film, is easily available, and does not require additional apparatus

Introduction The aim of this study was to examine the flexion stability of posterior stabilised (PS) compared with deep dished (DD) tibial inserts in PCL sacrificing total knee arthroplasty using posterior stress radiography. Methods Kneeling posterior stress radiographs at 90° of flexion were taken pre and post-operatively in 36 knees undergoing primary arthroplasty with PCL resection (26 DD and 10 PS implants). Sagittal plane tibial translation was measured. Results The deep dish inserts all showed posterior displacement (mean: −5.1 mm, range: −2 to −12 mm). The posterior stabilised implants were all displaced anteriorly (mean: +6.7 mm, range: +3 to +12 mm). The difference in translation was highly significant (P< 0.0001). There was a strong correlation between implant and position of the tibia (R = 0.86). In seven patients comparison was possible between a DD component in one knee and a PS implant in the other. There was a mean post-operative side to side difference of 11 mm (range: 5 to 21 mm). Conclusions This study discriminates between two implant types on stress x-rays. The posterior tibial displacement in the DD group suggests that this implant does not provide enough posterior flexion stability to compensate for the PCL resection. The anterior translation in the PS group has implications for the design and wear of the post as well as advice to patients about possibly avoiding kneeling in this PS design

Aim: To examine the flexion stability of posterior stabilised (PS) vs deep dished (DD) tibial inserts, in PCL sacrificing total knee arthroplasty using posterior stress radiography. Methods: A simple jig was designed to allow kneeling posterior stress radiographs (at 90 degrees flexion) to be taken. This method was used to take pre and post-operative radiographs in 36 knees undergoing primary arthroplasty with PCL resection (26 DD and 10 PS implants). Sagittal plane tibial translation was measured. Results: The DD inserts all showed posterior displacement (mean: −5.1 mm, range: −2 to −12mm). The PS implants were all displaced anteriorly (mean: +6.7mm, range: +3 to +12mm). The difference in translation was highly significant (P< 0.0001). There was a strong correlation between implant and position of the tibia (R=0.86). In 7 patients, comparison was possible between a DD component in one knee and a PS implant in the other. There was a mean post-operative side-to-side difference of 11mm (range: 5 to 21mm). Conclusions: This study validates a simple new method for flexion stress x-rays (by accurately discriminating between the two implant types). The posterior tibial displacement in the DD group suggests that this implant does not provide enough posterior flexion stability to compensate for the PCL resection. The anterior translation in the PS group has implications for the design and wear of the post, as well as advice to patients about possibly avoiding kneeling in this PS design

We will present the results of our different studies from 1979 till now. Between 1979 and 1984 we tested 1120 consecutive patients with distorsion trauma by stress x-rays, taking only the anterior drawer sign. 237 patients (21, 2 %) were treated operatively because of pathological instability. The correlation: operative findings/positive anterior drawer sign was 85 %. Because of our prospective study in 19 84: arthrography versus x-ray in 52 patients we abandoned the invasive arthrography because it did not give better information about the instability of the ankle. After an investigation of 42 patients with instable ankle joints in our and in the university hospital of Kuopio treated by Evans operation in 1983 with the outcome 42% anteriorly instable, 26% pain at the insertion point at metatarsus V, we looked for a better reconstruction method. We chose our own method, anatomical reinsertion of FTA and FC, and augmentation of FTA with half of syndesmosis anterior.20 patients, who were treated with this anatomical reconstruction technique(group A), and 20 patients, who underwent primary repair (group B), were controlled 2–4 years after operation. We reviewed 15 patients from group A and 17 from group B. Functional scores were good in both groups without significant difference and no difference in the mean talar translation between the two groups. In a second investigation -92–93 with 43 primary ligament repairs and 31 reconstructions, 89% were active athletes. The outcome after 2–4years was 2, 3% of primary repaired ankles were still painful vs. 22,6 of ankles in delayed reconstruction group. Improvement of anterior stress radiography 3,9mm of those with ligament repair and 1,5 mm of those with reconstructive procedures. This difference between these two groups was significant. Should we operate primarily or treat the patients adequately-air cast, active rehabilitation and only persisting instability by operation with an anatomic reconstruction??

Introduction. In valgus knees, ligament balance remain difficult when implanting a total knee arthroplasty (TKA), this leads some authors to systematically propose the use of constrained devices. Others prefer reserving higher constraints to cases where it is not possible to obtain final satisfactory balance: less than 5 of residual frontal laxity in extension in each compartment, and a tibiofemoral gap difference not in excess to 3mm between flexion and extension. The goal of the study was to assess if is possible to establish preoperative criteria that can predict a constrained design prosthetic implantation at surgery. Materials and Methods. A consecutive series of 93 total knee prostheses, implanted to treat a valgus deformity of more than 5 was retrospectively analysed. Preoperatively, full weight bearing long axis AP views A-P were performed: hip knee angle (HKA) averaged 195 (186 to 226), 36 knees had more than 15 of valgus, and 19 others more than 20 of valgus. Laxity was measured by stress radiographies with a TelosTM system at 100 N. Fifty-two knees had preoperative laxity in the coronal plane of more than 10. Fourteen knees had more than 5 laxity on the convex (medial) side, 21 knees had more than 10 laxity on the concave (lateral) side. Statistical assessment, using univariate analysis, identified the factors that led, at surgery, to an elevated constraint selection level; these factors of independence were tested by multivariate analysis. Logistical regression permitted the classification of the said factors by their odds ratios (OR). Results. High-constraints prostheses (CCK type) were used in 26 out of 93 TKA, the other TKA were regular posterostabilized (PS) prostheses. Statistically, the preoperative factors that led to the choice of a constrained prosthesis were: (1) valgus severity as measured by HKA (PS = (PS = 193, CCK = 198), (2) increased posterior tibial slope (PS = 4.8, CCK = 6.5), (3) low patellar height (using Blackburne and Peel index PS = 0.89, CCK = 0.77), (4) severity of laxity in valgus (PS = 2.3, CCK = 4.3). Among all these factors, the only independent one was laxity in valgus (convex side laxity) (p = 0.0008). OR analysis showed a two-fold increased probability of implanting an elevated constraints prosthesis for each one degree increment of laxity in valgus. Discussion. This study demonstrated that it was not the valgus angle severity but rather the convex medial side laxity that increased the frequency of constrained prostheses implantation. Other factors, as a low patellar height or an elevated posterior tibial slope, when associated, potentiate this possible prosthetic switch (to higher constraints) and should make surgeons aware, in these situations, of encountering difficulties when establishing ligament balance