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

In an initial randomised controlled trial (RCT) we segregated 180 patients to one of two knee positions following total knee replacement (TKR): six hours of knee flexion using either a jig or knee extension. Outcome measures included post-operative blood loss, fall in haemoglobin, blood transfusion requirements, knee range of movement, limb swelling and functional scores. A second RCT consisted of 420 TKR patients randomised to one of three post-operative knee positions: flexion for three or six hours post-operatively, or knee extension. Positioning of the knee in flexion for six hours immediately after surgery significantly reduced blood loss (p = 0.002). There were no significant differences in post-operative range of movement, swelling, pain or outcome scores between the various knee positions in either study. Post-operative knee flexion may offer a simple and cost-effective way to reduce blood loss and transfusion requirements following TKR. We also report a cautionary note regarding the potential risks of prolonged knee flexion for more than six hours observed during clinical practice in the intervening period between the two trials, with 14 of 289 patients (4.7%) reporting lower limb sensory neuropathy at their three-month review. Cite this article: Bone Joint J 2014;96-B:201–9

INTRODUCTION. Thorough understanding and feedback of the post-operative implant position relative to the pre-operative anatomy is missing in today's clinical practice. However, three dimensional insights in the local under or oversizing of the implant can provide important feedback to the surgeon. For the knee for instance, to identify a shift in the sagittal joint line that potentially links to mid-flexion instability or to identify zones at risk for soft tissue impingement. Despite a proven inferior outcome, clinical post-operative implant evaluation remains primarily based on bi-planar, static 2D x-rays rather than 3D imaging. Along with the cost, a possible reason is the increased radiation dose and/or metal artifact scatter in computed tomography (CT) and/or magnetic resonance imaging (MRI). These detrimental effects are now avoided by using recently released x-ray processing software. This technique uses standard-of-care post-operative x-rays in combination with a pre-operative CT and 3D file of the implant to determine the implant position relative to the pre-operative situation. The accuracy of this new technique is evaluated in this paper using patient cases. Therefore, the obtained implant position is benchmarked against post-operative CT scans. MATERIALS & METHODS. Retrospectively, 19 patients were selected who underwent total knee arthroplasty and received pre- and post-operative CT of their diseased knee. The CT scans were performed with a pixel size of 0.39 mm and slice spacing of 0.60 mm (Somatom, Siemens, München, Germany). All patients underwent TKA surgery using the same bi-cruciate substituting total knee (Journey II, Smith&Nephew, Memphis, USA). Following surgery, standard bi-planar standing x-rays of the operated knee was additionally performed as standard of care. To evaluate the implant position relative to the pre-operative situation, the 3D implants are first positioned on the post-operative CT slices. Using Mimics (Materialise NV, Leuven, Belgium), the pre-operative bone was subsequently automatically matched onto the post-operative scan to identify the implant location relative to the reconstructed pre-operative bone. This has been independently repeated by three observers to assess the inter-observer variability. Second, the post-operative bi-planar x-rays are combined with the reconstructed pre-operative bone and 3D file of the implant. This combination is performed using the 2D-to-3D conversion integrated in the recently launched X-ray module of Mimics. This module uses a contour based registration method to determine the implant and bone position using the post-operative x-rays. For both reconstruction methods, the implant position has been evaluated in six degrees of freedom using an automated Matlab routine; resulting in three translations and three rotations. RESULTS. From the evaluated implant positions, the root mean square error was derived between subsequent measurements. For the CT reconstruction based inter-observer evaluation, the median RMS error for all degrees of freedom is below 1 mm and 1 degree for both the femoral and tibial implant. Comparing the reconstructed CT implant position with the 2D-to-3D reconstruction, the median RMS difference between the implant positions remains below 1 mm and 1 degree except for the distraction/compression component and the internal/external rotation of the component. DISCUSSION. On average, the RMS difference between the 2D-to-3D conversion and the reconstructed post-operative CT exceeds the inter-observer RMS difference obtained using reconstructed post-operative CT. The differences are in line with previous cadaveric studies using the same reconstruction technique. The largest differences are seen for the femoral and tibial internal/external rotation. However, the obtained values are still within reasonable limits according to a recent review by De Valk et al., who reported an inter-observer variation of 3° for the femur and 2° for the tibia. In addition, the 2D-to-3D conversion displays a larger difference for the distraction/compression component. Since a true, golden standard measurement is lacking in our tests, it is not clear whether this error is attributed to the CT imaging or the 2D-to-3D conversion. Given the low inter-observer variation for this degree of freedom, it is hypothesized that this discrepancy is linked to the finite slice spacing for the CT scans. Apart from the obtained accuracy, the use of the 2D-to-3D module has the advantage of significantly reducing the radiation dose with approx. a factor 20. In addition, the imaging procedure needs no more than the standard imaging required by clinical practice

The Oxford knee score (OKS) is a validated and widely accepted disease-specific patient-reported outcome measure, but there is limited evidence regarding any long-term trends in the score. We reviewed 5600 individual OKS questionnaires (1547 patients) from a prospectively-collected knee replacement database, to determine the trends in OKS over a ten-year period following total knee replacement. The mean OKS pre-operatively was 19.5 (95% confidence interval (CI) 18.8 to 20.2). The maximum post-operative OKS was observed at two years (mean score 34.4 (95% CI 33.7 to 35.2)), following which a gradual but significant decline was observed through to the ten-year assessment (mean score 30.1 (95% CI 29.1 to 31.1)) (p < 0.001). A similar trend was observed for most of the individual OKS components (p < 0.001). Kneeling ability initially improved in the first year but was then followed by rapid deterioration (p < 0.001). Pain severity exhibited the greatest improvement, although residual pain was reported in over two-thirds of patients post-operatively, and peak improvement in the night pain component did not occur until year four. Post-operative OKS was lower for women (p < 0.001), those aged < 60 years (p < 0.003) and those with a body mass index > 35 kg/m. 2. (p < 0.014), although similar changes in scores were observed. This information may assist surgeons in advising patients of their expected outcomes, as well as providing a comparative benchmark for evaluating longer-term outcomes following knee replacement. Cite this article: Bone Joint J 2013;95-B:45–51

Pyrexia in the post-operative setting has often been associated with a possible systemic or wound infection. We assessed whether there is any justification for our concern regarding post-operative pyrexia following hip arthroplasty and subsequent deep prosthetic infection. Method:. Study 1. An assessment of the clinical outcome of 97 sequential patients who underwent 103 primary hip arthroplasty for primary osteoarthritis replacements. Daily temperature and systemic complications in the post-operative period were recorded. Clinical outcome was measured using an Oxford hip questionnaire. Patients had a mean follow-up of 5.2 years (range 3.5–7.2years). Study 2. A review of postoperative temperature records of 80 patients who had undergone primary total hip replacement. Thirty-one patients had required revision surgery at a mean time interval of 37.2 months (range 5–74 months) for confirmed deep prosthetic infection. The remaining Forty-nine patients were asymptomatic at a mean follow-up of 31.5 months. Results:. Study 1. Post-operative pyrexia of 38 degrees Celsius was present in 51% of patient’s undergoing primary hip replacement in the first post-operative week but in 21.1% no etiological cause could be identified. Clinical outcome measured by an oxford hip questionnaire was not influenced by the post-operative temperature pattern. Study 2. The mean peak temperature on the first post-operative day was significantly lower in patients with deep prosthetic infection then patients with a clinically normal outcome (p=0.01). Conclusion: Post-operative pyrexia is clearly not uncommon following primary arthroplasty and its presence should not be regarded as detrimental. Pyrexia in the post-operative setting is a component of the acute phase response to trauma and study 2 demonstrates patients who develop a low-grade infection following arthroplasty may have diminished febrile response to surgical trauma

Aims. The purpose of the present study was to evaluate the impact of intravenous tranexamic acid on the reduction of blood loss, transfusion rate, and early post-operative clinical outcome in total shoulder arthroplasty. Patients and Methods. A randomised, placebo-controlled trial which included 54 patients undergoing unilateral primary stemless anatomical or stemmed reverse total shoulder arthroplasty was undertaken. Patients received either 100 ml saline (placebo, n = 27), or 100 ml saline together with 1000 mg of tranexamic acid (TXA, n = 27) intravenously prior to skin incision and during wound closure. Peri-operative blood loss via an intra-articular drain was recorded and total blood loss was calculated. The post-operative transfusion rate was documented. Assessment of early clinical parameters included the visual analogue scale for pain (VAS), documentation of haematoma formation and adverse events. Results. Mean peri-operative blood drainage (placebo: 170 ml versus TXA: 50 ml, p = 0.001) and calculated mean total blood loss (placebo: 1248.2 ml versus TXA: 871.0 ml, p = 0.009) were significantly lower in the TXA group. No transfusions were necessary during the study period in either group. Mean VAS for pain significantly decreased from pre-operative (VAS 7) to the early post-operative period (VAS 1.7, p < 0.001). Significant differences regarding mean post-operative pain between placebo (VAS 2.0) and TXA (VAS 1.3) were detected (p = 0.05). The occurrence of haematomas was significantly more frequent in the placebo (59.3%, n = 16) than in the TXA group (25.9%, n = 6, p = 0.027). Whereas only mild haematomas developed in the TXA group, in the placebo group a total of 22.2% (n = 6) developed either moderate or severe haematomas. No adverse events associated with administration of TXA occurred. Conclusion. Intravenous administration of TXA successfully reduced mean peri-operative blood drainage, total estimated blood loss, pain during the first post-operative days, and haematoma formation in total shoulder arthroplasty. Cite this article: Bone Joint J 2017;99-B:1073–9

Objectives. Our objective was to predict the knee extension strength and post-operative function in quadriceps resection for soft-tissue sarcoma of the thigh. Methods. A total of 18 patients (14 men, four women) underwent total or partial quadriceps resection for soft-tissue sarcoma of the thigh between 2002 and 2014. The number of resected quadriceps was surveyed, knee extension strength was measured with the Biodex isokinetic dynamometer system (affected side/unaffected side) and relationships between these were examined. The Musculoskeletal Tumor Society (MSTS) score, Toronto Extremity Salvage Score (TESS), European Quality of Life-5 Dimensions (EQ-5D) score and the Short Form 8 were used to evaluate post-operative function and examine correlations with extension strength. The cutoff value for extension strength to expect good post-operative function was also calculated using a receiver operating characteristic (ROC) curve and Fisher’s exact test. Results. Extension strength decreased when the number of resected quadriceps increased (p < 0.001), and was associated with lower MSTS score, TESS and EQ-5D (p = 0.004, p = 0.005, p = 0.006, respectively). Based on the functional evaluation scales, the cutoff value of extension strength was 56.2%, the equivalent to muscle strength with resection of up to two muscles. Conclusion. Good post-operative results can be expected if at least two quadriceps muscles are preserved. Cite this article: A. Tanaka, Y. Yoshimura, K. Aoki, M. Kito, M. Okamoto, S. Suzuki, T. Momose, H. Kato. Knee extension strength and post-operative functional prediction in quadriceps resection for soft-tissue sarcoma of the thigh. Bone Joint Res 2016;5:232–238. DOI: 10.1302/2046-3758.56.2000631

Clinical, haematological or economic benefits of post-operative blood salvage with autologous blood re-transfusion have yet to be clearly demonstrated for primary total hip replacement. We performed a prospective randomised study to analyse differences in postoperative haemoglobin levels and homologous blood requirements in two groups of patients undergoing primary total hip replacement. A series of 158 patients was studied. In one group two vacuum drains were used and in the other the ABTrans autologous retransfusion system. A total of 58 patients (76%) in the re-transfusion group received autologous blood. There was no significant difference in the mean post-operative haemoglobin levels in the two groups. There were, however, significantly fewer patients with post-operative haemoglobin values less than 9.0 g/dl and significantly fewer patients who required transfusion of homologous blood in the re-transfusion group. There was also a small overall cost saving in this group

Introduction. Acute kidney injury is a recognised post-operative complication in primary joint replacement. Recently it has been demonstrated that antibiotic regimen can significantly impact on the proportion of patients who develop acute kidney impairment post-operatively. Within our unit an increased rate of acute kidney injury had been noted post-operatively over the last 5 years. This increase followed the introduction of a rapid recovery protocol for arthroplasty patients. Our aim was determine whether we could identify a causative factor or those who were at increased risk of post-operative renal impairment. Methods. Data were collected for 413 patients initially retrospectively but continued prospectively. Univariable and multivariable analysis was performed to determine any causative factors. The primary increase was 150% increase in baseline creatinine, but as some authors recognise an increase in 125% this was also analysed. Results. Within the 12 month period studied 23.3% of patients developed acute kidney injury, with an increase of 125% of their baseline creatinine. 8.23% of patients developed an increase of 150% in their creatinine levels. Age, previous renal failure and the pre-operative use of an ACE inhibitor were found to be statistically higher in the renal failure group. The uni-variable analysis also demonstrated that patients who received a small volume of post-operative intravenous fluids had a lower rate of renal failure than those who received no fluids (10% vs. 23%; p = 0.04). The multivariable regression analysis demonstrated that age was the only statistically significant positive predictive factor in developing renal failure. Antibiotic regimen had no effect. Discussion. Renal impairment has significant impact on patient morbidity and post-operative management. It increases the length of stay, and may potentially require more invasive therapy. We have demonstrated that the identified risk factors are non-modifiable but that a gentamicin and teicoplanin regimen was not an implicated causative factor

Aims. The aim of this study was to identify patient- and surgery-related risk factors for sustaining an early periprosthetic fracture following primary total hip arthroplasty (THA) performed using a double-tapered cementless femoral component (Bi-Metric femoral stem; Biomet Inc., Warsaw, Indiana). Patients and Methods. A total of 1598 consecutive hips, in 1441 patients receiving primary THA between January 2010 and June 2015, were retrospectively identified. Level of pre-operative osteoarthritis, femoral Dorr type and cortical index were recorded. Varus/valgus placement of the stem and canal fill ratio were recorded post-operatively. Periprosthetic fractures were identified and classified according to the Vancouver classification. Regression analysis was performed to identify risk factors for early periprosthetic fracture. Results. The mean follow-up was 713 days (1 to 2058). A total of 48 periprosthetic fractures (3.0%) were identified during the follow-up and median time until fracture was 16 days, (interquartile range 10 to 31.5). Patients with femoral Dorr type C had a 5.2 times increased risk of post-operative periprosthetic fracture compared with type B, while female patients had a near significant two times increased risk over time for post-operative fracture. Conclusion. Dorr type C is an independent risk factor for early periprosthetic fracture, following THA using a double tapered cementless stem such as the Bi-Metric. Surgeons should take bone morphology into consideration when planning for primary THA and consider using cemented femoral components in female patients with poor bone quality. Cite this article: Bone Joint J 2017;99-B:451–7

BACKGROUND. The need for post-operative manipulation under anesthesia (MUA) for stiffness after primary total knee arthroplasty is a frustrating complication that can lead to suboptimal outcomes if range-of-motion to a functional level is not regained. Implant morphology and kinematics, PCL imbalance, and soft-tissue balancing can all contribute to post-operative stiffness. Utilization of total knee arthroplasty components that replicate the native knee's medial ball and socket kinematics may lead to easier maintenance of flexion post-operatively compared to conventional components. PURPOSE. To determine if a medial pivot total knee arthroplasty design can reduce the need for post-operative MUA after primary total knee arthroplasty. METHODS. A retrospective chart review of primary total knee arthroplasties performed between 2013 and 2016 by a single fellowship-trained joint replacement surgeon was performed. Cases that met criteria for inclusion were: primary total knee arthroplasty, identifiable implant based on operative report and/or post-operative radiographs, immediate post-operative passive flexion against gravity of at least 110 degrees, and availability of post-operative follow-up notes documenting range-of-motion that was either satisfactory or necessitating need for MUA. The need for a MUA was deemed necessary if post-operative flexion was not beyond 90 degrees within six weeks of surgery. The percentage of patients requiring MUA for a group implanted with the EVOLUTION Medial Pivot System was compared to a group implanted with all other designs (Stryker Triathlon CR, PS, TS). RESULTS. One hundred fifty-six cases met criteria for inclusion and were reviewed. The Triathlon system was used predominantly in the first half of the study period and accounted for 65 (42%) of the cases performed. Six patients in this group underwent MUA and two patients required repeated MUA. An additional patient in the Triathlon group met the criteria for MUA but had other conditions which prevented the investigators from performing it. The percentage of patients who met the indication for MUA in the Triathlon group was 10.8%. The EVOLUTION system was used predominantly in the second half of the study period and accounted for 91 (58%) of the cases performed. There were two patients (2.2%) who met criteria for MUA and both patients subsequently underwent MUA. There was a statistically significant reduction in the number of patients meeting criteria for MUA in the EVOLUTION group compared with the Triathlon group (p=0.024). CONCLUSION. Utilization of a medial ball and socket design for primary total knee arthroplasty allows the polyethylene implant to control the position of the femur on the tibia. This design possibly allows for improved early maintenance of post-operative flexion, which may minimize the need for post-operative MUA. For any figures or tables, please contact authors directly (see Info & Metrics tab above).

Arthrofibrosis remains a dominant post-operative complication and reason for returning to the OR following total knee arthroplasty. Trauma induced by ligament releases during TKA soft tissue balancing and soft tissue imbalance are thought to be contributing factors to arthrofibrosis, which is commonly treated by manipulation under anesthesia (MUA). We hypothesized that a robotic-assisted ligament balancing technique where the femoral component position is planned in 3D based on ligament gap data would result in lower MUA rates than a measured resection technique where the implants are planned based solely on boney alignment data and ligaments are released afterwards to achieve balance. We also aimed to determine the degree of mechanical axis deviation from neutral that resulted from the ligament balancing technique. Methods. We retrospectively reviewed 301 consecutive primary TKA cases performed by a single surgeon. The first 102 consecutive cases were performed with a femur-first measured resection technique using computer navigation. The femoral component was positioned in neutral mechanical alignment and at 3° of external rotation relative to the posterior condylar axis. The tibia was resected perpendicular to the mechanical axis and ligaments were released as required until the soft tissues were sufficiently balanced. The subsequent 199 consecutive cases were performed with a tibia-first ligament balancing technique using a robotic-assisted TKA system. The tibia was resected perpendicular to the mechanical axis, and the relative positions of the femur and tibia were recorded in extension and flexion by inserting a spacer block of appropriate height in the medial and lateral compartments. The position, rotation, and size of the femoral component was then planned in all planes such that the ligament gaps were symmetric and balanced to within 1mm (Figure 1). Bone resection values were used to define acceptable limits of implant rotation: Femoral component alignment was adjusted to within 2° of varus or valgus, and within 0–3° of external rotation relative to the posterior condyles. Component flexion, anteroposterior and proximal-distal positioning were also adjusted to achieve balance in the sagittal plane. A robotic-assisted femoral cutting guide was then used to resect the femur according to the plan (Figure 2). CPT billing codes were reviewed to determine how many patients in each group underwent post-operative MUA. Post-operative mechanical alignment was measured in a subset of 50 consecutive patients in the ligament balancing group on standing long-leg radiographs by an independent observer. Results. Post-operative MUA rates were significantly lower in the ligament balancing group (0.5%; 1/199) than in the measured resection group (3.9%; 4/102), p=0.051. 91.3% (42/46) of knees were within 3° and 100% (46/46) were within 4° of neutral alignment to the mechanical axis post-operatively in the ligament balancing group. Conclusions. Gap driven femoral based planning in TKA resulted in a significantly lower post-operative manipulation rate than in the measured resection approach, while maintaining acceptable overall alignment to the mechanical axis

Aim. Perioperative hyperglycemia has many etiologies including medication, impaired glucose tolerance, uncontrolled diabetes mellitus (DM), or stress, the latter of which is common to post-surgical patients. This acute hyperglycemia may impair the ability of the host to combat infection. 1. Our study aims to investigate if post-operative day 1 (POD1) blood glucose level is associated with complications, including periprosthetic joint infection (PJI), after total joint arthroplasty (TJA) and to determine a threshold for glycemic control that surgeons should strive for during a patient's hospital stay. Method. A single-institution retrospective review was conducted on 24,857 primary TJAs performed from 2001–2015. Demographics, Elixhauser comorbidities, laboratory values, complications and readmissions were collected. POD1 morning blood glucose levels were utilized and correlated with PJI, as defined by the Musculoskeletal Infection Society criteria. The Wald test was used to determine the influence of covariates on complication rate. An alpha level of 0.05 was used to determine statistical significance. Results. The rate of PJI significantly increased linearly from blood glucose levels of 115 mg/dL onwards. We determined that blood glucose (OR 1.004, 95% CI: 1.001–1.006, p=0.001), male gender (OR 1.480, 95% CI: 1.185–1.848, p=0.001), body mass index (OR 1.049, 95% CI: 1.033–1.065, p<0.001), operative time (OR 1.004, 95% CI: 1.001–1.007, p=0.006), length of stay (OR 1.059, 95% CI: 1.038–1.080, p<0.001), post-operative hematocrit (OR 0.751, 95% ci: 0.621–0.909, p=0.003), peripheral vascular disease (OR 1.942, 95% CI: 1.042–3.617, p=0.037), liver disease (OR 2.576, 95% CI: 1.344–4.935, p=0.004), rheumatic disease (OR 1.991, 95% CI: 1.266–3.132, p=0.003), and alcohol abuse (OR 2.588, 95% CI: 1.096–6.110, p=0.030) were associated with PJI. The Youden index was used to determine an optimal blood glucose threshold of 132 mg/dL to reduce the likelihood of PJI. The PJI rate in the entire cohort was 1.59% (1.46% in non-diabetics compared to 2.39% in diabetics, p=0.001). Diabetics did not have an association between blood glucose level and PJI (OR 1.002, 95% CI: 0.998–1.006, p=0.331), although there was a linear trend for postoperative glucose predicting PJI. Conclusions. The relationship between POD1 blood glucose levels and PJI increased linearly, with an optimal cut off of 132 mg/dL. Immediate and strict post-operative glycemic control is critical in reducing post-operative complications, and we demonstrate that even mild hyperglycemia is significantly associated with PJI

The accurate positioning of the total knee arthroplasty affects the survival of the implants(1). Alignment of the femoral component in relation to the native knee is best determined using pre- and post-operative 3D-CT reconstruction(2). Currently, the scans are visualised on separate displays. There is a high inter- and intra-observer variability in measurements of implant rotation and translation(3). Correct alignment is required to allow a direct comparison of the pre- and post-operative surfaces. This is prevented by the presence of the prostheses, the bone shape alteration around the implant, associated metal artefacts, and possibly a segmentation noise. The aim is to create a novel method to automatically register pre- and post-operative femora for the direct comparison of the implant and the native bone. The concept is to use post-operative femoral shaft segments free of metal noise and of surgical alteration for alignment with the pre-operative scan. It involves three steps. Firstly, using principal component analysis, the femoral shafts are re-oriented to match the X axis. Secondly, variants of the post-operative scan are created by subtracting 1mm increments from the distal femoral end. Thirdly, an iterative closest point algorithm is applied to align the variants with the pre-operative scan. For exploratory validation, this algorithm was applied to a mesh representing the distal half of a 3D scanned femur. The mesh of a prosthesis was blended with the femur to create a post-operative model. To simulate a realistic environment, segmentation and metal artefact noise were added. For segmentation noise, each femoral vertex was translated randomly within +−1mm,+−2mm,+−3mm along its normal vector. To create metal artefact random noise was added within 50 mm of the implant points in the planes orthogonal to the shaft. The alignment error was considered as the average distance between corresponding points which are identical in pre- and post-operative femora. These preliminary results obtained within a simulated environment show that by using only the native parts of the femur, the algorithm was able to automatically register the pre- and post-operative scans even in presence of the implant. Its application will allow visualisation of the scans on the same display for the direct comparison of the perioperative scans. This method requires further validation with more realistic noise models and with patient data. Future studies will have to determine if correct alignment has any effect on inter- and intra-observer variability

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

The accurate reconstruction of hip anatomy and biomechanics is thought to be important in achieveing good clinical outcomes following total hip arthroplasty (THA). To this end some newer hip designs have introduced further modularity into the design of the femoral component such that neck­shaft angle and anteversion, which can be adjusted intra-operatively. The clinical effect of this increased modularity is unknown. We have investigated the changes in these anatomical parameters following conventional THA with a prosthesis of predetermined neck–shaft angle and assessed the effect of changes in the hip anatomy on clinical outcomes. . In total, 44 patients (mean age 65.3 years (standard deviation (. sd. ) 7); 17 male/27 female; mean body mass index 26.9 (kg/m²) (. sd. 3.1)) underwent a pre- and post-operative three-dimensional CT scanning of the hip. The pre- and post-operative neck–shaft angle, offset, hip centre of rotation, femoral anteversion, and stem alignment were measured. Additionally, a functional assessment and pain score were evaluated before surgery and at one year post-operatively and related to the post-operative anatomical changes. The mean pre-operative neck–shaft angle was significantly increased by 2.8° from 128° (. sd.  6.2; 119° to 147°) to 131° (. sd. 2.1; 127° to 136°) (p = 0.009). The mean pre-operative anteversion was 24.9° (. sd. 8; 7.9 to 39.1) and reduced to 7.4° (. sd. 7.3; -11.6° to 25.9°) post-operatively (p < 0.001). The post-operative changes had no influence on function and pain. Using a standard uncemented femoral component, high pre- and post-operative variability of femoral anteversion and neck–shaft angles was found with a significant decrease of the post-operative anteversion and slight increase of the neck–shaft angles, but without any impact on clinical outcome. Cite this article: Bone Joint J 2015;97-B:1615–22

TKA is one of the most common orthopaedic operations performed worldwide and it is largely successful in pain relief and functional recovery. However, when pain persists post-operatively the thorough evaluation must be instituted. Extra-articular causes of knee pain include; hip pathology, lumbar spine degenerative disease or radicular symptoms, focal neuropathy, vascular disease, and chronic regional pain syndrome. Intra-articular causes of knee pain: infection, crepitation/ clunk, patella osteonecrosis, patella mal-tracking, soft tissue imbalance, malalignment, arthrofibrosis, component loosening, implant wear, ilio-tibial band irritation, and bursitis. Other causes of pain to rule out are component overhang with soft tissue irritation, recurrent hemarthrosis secondary to synovial impingement or entrapment, non-resurfaced patella, and metal sensitivity. A careful history may reveal previous knee surgeries with delayed healing or prolonged drainage, chronology of sign and symptoms, co-morbid medical conditions, jewel or metal sensitivity. Physical exam should help with specific signs in the operated knee. Targeted local anesthetic blocks are helpful and response to lumbar sympathetic blocks determines presence of CRPS. Lab tests are important: ESR, CRP, WBC, aspiration with manual cell count and diff, leukocyte esterase dipstick, RA titers, metal derm patch testing, nuclear scans, CT best for rotational malalignment,, and MARS MRI. More recently patient satisfaction as an outcome measure has shown TKA results not satisfactory in 11 – 18% of patients. A discordance of patient vs. surgeon satisfaction exists so the following factors may help improve this: correct patient selection, establishing and correlating surgeon-patient expectations, peri-operative optimisation of patient comorbidities to help avoid preventable complications, use of pre- and post-operative pathways. Satisfaction rates can best be improved by addressing the previous points with patients prior to TKA surgery

Problems with chondral toxicity caused by prolonged exposure to local anaesthetics have been increasingly recognised. However, day-case hip arthroscopic surgery is frequently carried out using an intraarticular depot of local anaesthetic as post-operative analgesia plus additional opiate or oral analgesia as required. We aimed to evaluate the efficacy of three different post-operative analgesic regimes at hip arthroscopy, in particular examining whether intraarticular local anaesthetics gave any benefit. We investigated 71 consecutive patients undergoing day-case hip arthroscopy and prospectively audited their post-operative analgesic requirements. Each patient was given one of three alternative post-operative analgesic regimes. Group A (n=29) received bupivicaine 0.25% 10ml intraarticular and 20ml peri-portal skin infiltration, group B (n=23) had bupivicaine 0.25% 20ml peri-portal skin infiltration only, and group C (n=19) had no infiltration. Outcome measures were visual analogue scores (VAS) at time-points T1 (immediate post-operatively), T2 (one hour post-operatively), T3 (two hours post-operatively), and T4 (four hours post-operatively). Total opiate consumption was also recorded. There was significantly less post-operative pain in group A, compared with group C at T1 (p=0.03) and T2 (p=0.004), and compared with group B at T3 (p=0.02) and T4 (p=0.03). There were no significant differences in VAS between groups B and C at any time-points. Group A used significantly less opiates post-operatively compared with group B (p=0.008) or C (p< 0.001) but there was no significant difference in opiate use between groups B and C. There are no previous studies relating to hip arthros-copy post-operative analgesic requirements. Intraarticular local anaesthetic significantly reduces post-operative pain, but at what cost to the chondral surface? Local skin infiltration of the arthroscopy portals does not significantly alter pain levels or opiate requirements. Avoidance of intararticular local anaesthetic raises opiate requirements. We require improved alternative analgesic regimes

Purpose. Total knee arthroplasty (TKA) is one of the most successful surgeries with respect to relieving pain and restoring function of the knee. However, some studies have reported that patients are not always satisfied with their results after TKA. The aim of this study was to determine which factors contribute to patient's satisfaction after TKA. Methods. We evaluated 69 patients who had undergone 76 primary TKAs between March 2012 and June 2013, and assessed patient- and physician- reported scores using the 2011 Knee Society Scoring System and clinical variables before and after TKAs. We determined the correlation between patient satisfaction and clinical variables. Results. The mean (SD) pre-operative score was 8.2 (4.9) for symptoms, 11.5 (4.5) for patient's satisfaction, 13.1 (2.2) for patient's expectations, and 35.4 (18.2) for functional activities. The mean (SD) post-operative score was 16.3 (5.0) for symptoms, 20.7 (6.4) for patient's satisfaction, 9.1 (2.3) for patient's expectations, and 47.4 (19.6) for functional activities. We found that physician- reported scores were higher than patient- reported scores, and improvement in patient- reported scores was lower than that of physician- reported scores following TKA. We did not found a correlation between any pre-operative variables including expectation and post-operative satisfaction. Post-operative symptoms (r=0.51, p<0.01) and functions (r=0.39, p<0.01) correlated with post-operative satisfaction. The predictors of patient dissatisfaction after TKA were remaining symptoms and low postoperative activities. Conclusions. Our study demonstrates that to relieve pain and to restore activities is important for increasing patient satisfaction after TKA. The 2011 Knee Society Scoring System allows surgeons to appreciate differences in the priorities of patients with TKA

Background. The accurate positioning of the total knee arthroplasty affects the survival of the implants(1). Alignment of the femoral component in relation to the native knee is best determined using pre- and post-operative 3D-CT reconstruction(2). Currently, the scans are visualised on separate displays. There is a high inter- and intra-observer variability in measurements of implant rotation and translation(3). Correct alignment is required to allow a direct comparison of the pre- and post-operative surfaces. This is prevented by the presence of the prostheses, the bone shape alteration around the implant, associated metal artefacts, and possibly a segmentation noise. Aim. Create a novel method to automatically register pre- and post-operative femora for the direct comparison of the implant and the native bone. Methods. The concept is to use post-operative femoral shaft segments free of metal noise and of surgical alteration for alignment with the pre-operative scan. It involves three steps. Firstly, using principal component analysis, the femoral shafts are re-oriented to match the X axis. Secondly, variants of the post-operative scan are created by subtracting 1mm increments from the distal femoral end (Fig1). Thirdly, an iterative closest point algorithm is applied to align the variants with the pre-operative scan. For exploratory validation, this algorithm was applied to a mesh representing the distal half of a 3D scanned femur. The mesh of a prosthesis was blended with the femur to create a post-operative model. To simulate a realistic environment, segmentation and metal artefact noise were added. For segmentation noise, each femoral vertex was translated randomly within +−1mm,+−2mm,+−3mm along its normal vector. To create metal artefact random noise was added within 50 mm of the implant points in the planes orthogonal to the shaft. The alignment error was considered as the average distance between corresponding points which are identical in pre- and post-operative femora. Results. Figure 2 shows, that when the implant zone is completely ignored, the error reaches a minimum plateau to below 1mm level. Different levels of segmentation noise had low impact on error value. Conclusions. These preliminary results obtained within a simulated environment show that by using only the native parts of the femur, the algorithm was able to automatically register the pre- and post-operative scans even in presence of the implant. Its application will allow visualisation of the scans on the same display for the direct comparison of the perioperative scans. This method requires further validation with more realistic noise models and with patient data. Future studies will have to determine if correct alignment has any effect on inter- and intra-observer variability. For figures, please contact authors directly.