Introduction. Individuals with significant hip and knee trauma receive total knee (TKA) and total hip arthroplasty (THA) as definitive end-stage procedures. In Aotearoa, injury-related costs, including workers compensation, may be funded by ACC. With a steady increase of arthroplasty procedures in Aotearoa, we aim to understand the magnitude and characteristics of such procedures to inform future healthcare strategies. Method. This is a longitudinal collaborative study from 1st January 2000 to 31st December 2020, using ACC and New Zealand Joint Registry databases. Total cost was subcategorised into social and medical cost for analysis. Results. ACC funded 10179 TKA and 5611 THA, amounting to 918 million New Zealand Dollars. Most clients were between 55 and 65 years of age at time of surgery, with greater representation by Male sex and European prioritised ethnicity. Māori and Pacific peoples represent less than 10% of the study population. ACC identified requiring more than 182 days of workers’ compensation as a significant marker for needing additional supports. Risk of this was 21% for TKA and 11% for THA, with risk factors being younger age (RR 0.96), Male sex (TKA RR 1.12, THA RR 1.23), and heavy work-types (TKA RR 1.50, THA RR 1.57). Discussion. Supporting individuals with post-traumatic lower limb arthroplasty is costly. Workers’ compensation contributes to a significant proportion of social expenditure. Risk factors for increased cost utilisation can be used to highlight vulnerable clients and target interventions. Conclusions. This is one of few nationwide studies investigating the healthcare cost of post-traumatic lower limb arthroplasty. We need to focus on injury prevention, targeted treatment, and rehabilitation protocols to improve recovery and reduce time off work. These findings would be of interest to multiple stakeholders

Objective. To evaluate the effect of claiming compensation on health status for people with mild to moderate injuries sustained in road traffic collisions (RTC). Methods. The design was a prospective cohort study in the Australian Capital Territory (ACT), Australia and a fault based compensation system. The subjects were people with mild to moderate musculoskeletal injuries who presented to the emergency department within 7 days of an RTC. Outcome Measures were Physical Component Score (PCS) and Mental Component Score (MCS) of the Short Form 36 (SF-36) health status measure; Hospital Anxiety and Depression Scale (HADS); and the Functional Rating Index (FRI). These measures were recorded immediately RTC, and at 6 and 12 months. Results. Ninety-five people were enrolled a mean of 8.6 days following RTC; 86% were followed up at 12 months. Mean age was 37 years; 61% were female; and 91% were employed at the time of injury. Compensation was claimed by 33% of enrolled subjects, and 25% engaged a lawyer. There were no significant differences in patient demographics or injury-related factors between the groups. As expected, passengers and people involved in multiple vehicle crashes more frequently claimed compensation. At each time-point, claiming compensation resulted in significantly worse scores for SF-36 PCS (-5.5 (95%CI -8.6 to -2.4), p = 0.001), HADS Anxiety (1.7 (95%CI 0.17 to 3.3), p = 0.048), and FRI (11.2 (95%CI 3.9 to 18.5), p = 0.003). For both groups, health status improved at the same rate, with significant improvement between baseline and 6 months, but no further improvement between 6 and 12 months. Conclusion. Claiming compensation had a significant negative effect on health status following mild to moderate musculoskeletal injuries sustained in RTC. However, whether this negative effect was due to claiming compensation itself or the presence of other unmeasured factors cannot be determined

INTRODUCTION

In total hip arthroplasty, preoperative planning is almost indispensable. Moreover, 3-dimensional preoperative planning became popular recently. Anteversion management is one of the most important factors in preoperative planning to prevent dislocation and to obtain better function.

In arthritic hip patients osteophytes are often seen on both femoral head and acetabulum. Especially on femoral head, osteophytes are often seen at posterior side and its surface creates smooth round contour that assumes new joint surface. (Fig. 1). We can imagine new femoral head center tracing that new joint surface.

Introduction

The number of revision hip arthroplasty procedures is rising annually with 7852 such operations performed in the UK in 2010. These are expensive procedures due to pre-operative investigation, surgical implants and instrumentation, protracted hospital stay, and pharmacological costs. There is a paucity of robust literature on the costs associated with the common indications for this surgery.

Traumatic rotator cuff injuries can be a leading cause of prolonged shoulder pain and disability, and contribute to significant morbidity and healthcare costs. Previous studies have shown evidence of socio-demographic disparities with these injuries. The purpose of this nationwide study was to better understand these disparities based on ethnicity, sex, and socio-economic status, in order to inform future healthcare strategies. Accident Compensation Corporation (ACC) is a no-fault comprehensive compensation scheme encompassing all of Aotearoa/New Zealand (population in 2018, 4.7 million). Using the ACC database, traumatic rotator cuff injuries were identified between January 2010 and December 2018. Injuries were categorized by sex, ethnicity, age and socioeconomic deprivation index of the claimant. During the 9-year study period, there were 351,554 claims accepted for traumatic rotator cuff injury, which totalled over $960 million New Zealand Dollars. The greatest proportion of costs was spent on vocational support (49.8%), then surgery (26.3%), rehabilitation (13.1%), radiology (8.1%), general practitioner (1.6%) and “Other” (1.1%). Asian, Māori (Indigenous New Zealanders), and Pacific peoples were under-represented in the age-standardized proportion of total claims and had lower rates of surgery than Europeans. Māori had higher proportion of costs spent on vocational support and lower proportions spent on radiology, rehabilitation and surgery than Europeans. Males had higher number and costs of claims and were more likely to have surgery than females. There were considerably fewer claims from areas of high socio-economic deprivation. This large nation-wide study demonstrates the important and growing economic burden of rotator cuff injuries. Indirect costs, such as vocational supports, are a major contributor to the cost suggesting improving treatment and rehabilitation protocols would have the greatest economic impact. This study has also identified socio-demographic disparities which need to be addressed in order to achieve equity in health outcomes

Radial head fractures are relatively common, representing approximately one-third of all elbow fractures. Outcomes are generally inversely proportional to the amount of force involved in the mechanism of injury, with simple fractures doing better than more comminuted ones. However, the prognosis for these fractures may also be influenced by associated injuries and patient-related factors (age, body index mass, gender, tobacco habit, etc.) The purpose of this study is to evaluate which factors will affect range of motion and function in partial radial head fractures. The hypothesis is that conservative treatment yields better outcomes. This retrospective comparative cohort study included 43 adult volunteers with partial radial head fracture, a minimum one-year follow up, separated into a surgical and non-surgical group. Risk factors were: associated injury, heterotopic ossification, worker's compensation, and proximal radio-ulnar joint implication. Outcomes included radiographic range of motion measurement, demographic data, and quality of life questionnaires (PREE, Q-DASH, MEPS). Mean follow up was 3.5 years (1–7 years). Thirty patients (70%) had associated injuries with decreased elbow extension (−11°, p=0.004) and total range of motion (−14°, p=0.002) compared to the other group. Heterotopic ossification was associated with decreased elbow flexion (−9°, p=0.001) and fractures involved the proximal radio-ulnar joint in 88% of patients. Only worker's compensation was associated with worse scores. There was no difference in terms of function and outcome between patients treated nonsurgically or surgically. We found that associated injuries, worker's compensation and the presence of heterotopic ossification were the only factors correlated with a worse prognosis in this cohort of patients. Given these results, the authors reiterate the importance of being vigilant to associated injuries

The choice of whether to perform antegrade intramedullary nailing (IMN) or plate fixation (PF) poses a conundrum for the surgeon who must strike the balance between anatomical restoration while reducing elbow and shoulder functional impairment. Most humeral middle third shaft fractures are amenable to conservative management given the considerable acceptable deformity and anatomical compensation by patients. This study is concerned with the patient reported outcomes regarding shoulder and elbow function for IMN and PF respectively. A prospective cohort study following up all the cases treated surgically for middle third humeral fractures from 2016 to 2022 at a single centre. Telephonically an analogue pain score, an American Shoulder and Elbow Society (ASES) score for shoulder function and the Oxford Elbow score (OES) for elbow function were obtained. One hundred and three patients met the inclusion criteria. Twenty four patients participated in the study, fifteen had IMN (62.5%) and nine had PF (37.5%.). The shoulder function outcomes showed no statistical difference with an average ASES score of sixty-six for the IMN group and sixty-nine for the PF group. Women and employed individuals expressed greater functional impairment. Hand dominance has no impact on the scores of elbow and shoulder function post operatively. The impairment of abduction score post antegrade nailing was higher in the antegrade nailing group than the plated group. The OES demonstrated greater variance in elbow function in the PF group with the IMN group expressing greater elbow disfunction. This study confirms that treatment of middle third humerus shaft fractures by plate fixation is marginally superior to antegrade intramedullary nailing in preserving elbow function and abduction ability

We test the clinical validity and financial implications of the proposed Choosing Wisely statement: “Using ultrasound as a screening test for shoulder instability is inappropriate in people under 30 years of age, unless there is clinical suspicion of a rotator cuff tear.”. A retrospective chart review from a specialist shoulder surgeon's practice over a two-year period recorded 124 patients under the age of 30 referred with shoulder instability. Of these, forty-one had already had ultrasound scans performed prior to specialist review. The scan results and patient files were reviewed to determine the reported findings on the scans and whether these findings were clinically relevant to diagnosis and decision-making. Comparison was made with subsequent MRI scan results. The data, obtained from the Accident Compensation Corporation (ACC), recorded the number of cases and costs incurred for ultrasound scans of the shoulder in patients under 30 years old over a 10-year period. There were no cases where the ultrasound scan was considered useful in decision-making. No patient had a full thickness rotator cuff tear. Thirty-nine of the 41 patients subsequently had MRI scans. The cost to the ACC for funding ultrasound scans in patients under 30 has increased over the last decade and exceeded one million dollars in the 2020/2021 financial year. In addition, patients pay a surcharge for this test. The proposed Choosing Wisely statement is valid. This evidence supports that ultrasound is an unnecessary investigation for patients with shoulder instability unless there is clinical suspicion of a rotator cuff tear. Ultrasound also incurs costs to the insurer (ACC) and the patient. We recommend x-rays and, if further imaging is indicated, High Tech Imaging with MRI and sometimes CT scans in these patients

Meniscal repairs are commonly performed during anterior cruciate ligament (ACL) reconstruction. This study aimed to identify the risk factors for meniscal repair failure following concurrent primary ACL reconstruction. Primary ACL reconstructions with a concurrent repair of a meniscal tear recorded in the New Zealand ACL Registry between April 2014 and December 2018 were analyzed. Meniscal repair failure was defined as a patient who underwent subsequent meniscectomy, and was identified after cross-referencing data from the ACL Registry with the national database of the Accident Compensation Corporation (ACC). Multivariate Cox regression was performed to produce hazard ratios (HR) with 95% confidence intervals (CI) to identify the patient and surgical risk factors for meniscal repair failure. 2041 meniscal repairs were analyzed (medial = 1235 and lateral = 806). The overall failure rate was 9.4% (n = 192). Failure occurred in 11.1% of medial (137/1235) and 6.8% of lateral (55/806) meniscal repairs. The risk of medial failure was higher with hamstring tendon autografts (adjusted HR = 2.00, 95% CI 1.23 – 3.26, p = 0.006) and in patients with cartilage injury in the medial compartment (adjusted HR = 1.56, 95% CI 1.09 – 2.23, p = 0.015). The risk of lateral failure was higher when the procedure was performed by a surgeon with an annual case volume of less than 30 ACL reconstructions (adjusted HR = 1.92, 95% CI 1.10 – 3.33, p = 0.021). Age, gender, time from injury-to-surgery and femoral tunnel drilling technique did not influence the risk of meniscal repair failure. When repairing a meniscal tear during ACL reconstruction, the use of a hamstring tendon autograft or the presence of cartilage injury in the medial compartment increases the risk of medial meniscal repair failure. Lower surgeon case volume increases the risk of lateral meniscal repair failure

Arthrofibrosis is a less common complication following anterior cruciate ligament (ACL) reconstruction and there are concerns that undergoing early surgery may be associated with arthrofibrosis. The aim of this study was to identify the patient and surgical risk factors for arthrofibrosis following primary ACL reconstruction. Primary ACL reconstructions prospectively recorded in the New Zealand ACL Registry between April 2014 and December 2019 were analyzed. The Accident Compensation Corporation (ACC) database was used to identify patients who underwent a subsequent reoperation with review of operation notes to identify those who had a reoperation for “arthrofibrosis” or “stiffness”. Univariate Chi-Square test and multivariate Cox regression analysis was performed. Hazard ratios (HR) with 95% confidence intervals (CI) were computed to identify the risk factors for arthrofibrosis. 9617 primary ACL reconstructions were analyzed, of which 215 patients underwent a subsequent reoperation for arthrofibrosis (2.2%). A higher risk of arthrofibrosis was observed in female patients (adjusted HR = 1.67, 95% CI 1.22 – 2.27, p = 0.001), patients with a history of previous knee surgery (adjusted HR = 1.97, 95% CI 1.11 – 3.50, p = 0.021) and when a transtibial femoral tunnel drilling technique was used (adjusted HR = 1.55, 95% CI 1.06 – 2.28, p = 0.024). Patients who underwent early ACL reconstruction within 6 weeks of their injury did not have a higher risk of arthrofibrosis when compared to patients who underwent surgery more than 6 weeks after their injury (3.5% versus 2.1%, adjusted HR = 1.56, 95% CI 0.97 – 2.50, p = 0.07). Age, graft type and concomitant meniscal injury did not influence the rate of arthrofibrosis. Female sex, a history of previous knee surgery and a transtibial femoral tunnel drilling technique are risk factors for arthrofibrosis following primary ACL reconstruction

Background. Anterior cruciate ligament (ACL) reconstruction with concomitant meniscal injury occurs frequently. Meniscal repair is associated with improved long-term outcomes compared to resection but is also associated with a higher reoperation rate. Knowledge of the risk factors for repair failure may be important in optimizing patient outcomes. Purpose. This study aimed to identify the patient and surgical risk factors for meniscal repair failure, defined as a subsequent meniscectomy, following concurrent primary ACL reconstruction. Methods. Data recorded by the New Zealand ACL Registry and the Accident Compensation Corporation, the New Zealand Government's sole funder of ACL reconstructions and any subsequent surgery, was reviewed. Meniscal repairs performed with concurrent primary ACL reconstruction was included. Root repairs were excluded. Univariate and multivariate survival analysis was performed to identify the patient and surgical risk factors for meniscal repair failure. Results. Between 2014 and 2020, a total of 3,024 meniscal repairs were performed during concurrent primary ACL reconstruction (medial repair = 1,814 and lateral repair = 1,210). The overall failure rate was 6.6% (n = 201) at a mean follow-up of 2.9 years, with a failure occurring in 7.8% of medial meniscal repairs (142 out of 1,814) and 4.9% of lateral meniscal repairs (59 out of 1,210). The risk of medial failure was higher in patients with a hamstring tendon autograft (adjusted HR = 2.20, p = 0.001), patients aged 21–30 years (adjusted HR = 1.60, p = 0.037) and in those with cartilage injury in the medial compartment (adjusted HR = 1.75, p = 0.002). The risk of lateral failure was higher in patients aged ≤ 20 years (adjusted HR = 2.79, p = 0.021) and when the procedure was performed by a surgeon with an annual ACL reconstruction case volume of less than 30 (adjusted HR = 1.84, p = 0.026). Conclusion. When performing meniscal repair during a primary ACL reconstruction, the use of a hamstring tendon autograft, younger age and the presence of concomitant cartilage injury in the medial compartment increases the risk of medial meniscal repair failure, whereas younger age and low surgeon volume increases the risk of lateral meniscal repair failure

Despite the current trend favoring surgical treatment of displaced intra-articular calcaneal fractures (DIACFs), studies have not been able to demonstrate superior functional outcomes when compared to non-operative treatment. These fractures are notoriously difficult to reduce. Studies investigating surgical fixation often lack information about the quality of reduction even though it may play an important role in the success of this procedure. We wanted to establish if, amongst surgically treated DIACF, an anatomic reduction led to improved functional outcomes at 12 months. From July 2011 to December 2020, at a level I trauma center, 84 patients with an isolated DIACF scheduled for surgical fixation with plate and screws using a lateral extensile approach were enrolled in this prospective cohort study and followed over a 12-month period. Post-operative computed tomography (CT) imaging of bilateral feet was obtained to assess surgical reduction using a combination of pre-determined parameters: Böhler's angle, calcaneal height, congruence and articular step-off of the posterior facet and calcaneocuboid (CC) joint. Reduction was judged anatomic when Böhler's angle and calcaneal height were within 20% of the contralateral foot while the posterior facet and CC joint had to be congruent with a step-off less than 2 mm. Several functional scores related to foot and ankle pathology were used to evaluate functional outcomes (American Orthopedic Foot and Ankle Score - AOFAS, Lower Extremity Functional Score - LEFS, Olerud and Molander Ankle Score - OMAS, Calcaneal Functional Scoring System - CFSS, Visual Analog Scale for pain - VAS) and were compared between anatomic and nonanatomic DIAFCs using Student's t-test. Demographic data and information about injury severity were collected for each patient. Among the 84 enrolled patients, 6 were excluded while 11 were lost to follow-up. Thirty-nine patients had a nonanatomic reduction while 35 patients had an anatomic reduction (47%). Baseline characteristics were similar in both groups. When we compared the injury severity as defined by the Sanders’ Classification, we did not find a significant difference. In other words, the nonanatomic group did not have a greater proportion of complex fractures. Anatomically reduced DIACFs showed significantly superior results at 12 months for all but one scoring system (mean difference at 12 months: AOFAS 3.97, p = 0.12; LEFS 7.46, p = 0.003; OMAS 13.6, p = 0.002, CFSS 7.5, p = 0.037; VAS −1.53, p = 0.005). Univariate analyses did not show that smoking status, worker's compensation or body mass index were associated with functional outcomes. Moreover, fracture severity could not predict functional outcomes at 12 months. This study showed superior functional outcomes in patients with a DIACF when an anatomic reduction is achieved regardless of the injury severity

Despite the current trend favoring surgical treatment of displaced intra-articular calcaneal fractures (DIACFs), studies have not been able to demonstrate superior functional outcomes when compared to non-operative treatment. These fractures are notoriously difficult to reduce. Studies investigating surgical fixation often lack information about the quality of reduction even though it may play an important role in the success of this procedure. We wanted to establish if, amongst surgically treated DIACF, an anatomic reduction led to improved functional outcomes at 12 months. From July 2011 to December 2020, at a level I trauma center, 84 patients with an isolated DIACF scheduled for surgical fixation with plate and screws using a lateral extensile approach were enrolled in this prospective cohort study and followed over a 12-month period. Post-operative computed tomography (CT) imaging of bilateral feet was obtained to assess surgical reduction using a combination of pre-determined parameters: Böhler's angle, calcaneal height, congruence and articular step-off of the posterior facet and calcaneocuboid (CC) joint. Reduction was judged anatomic when Böhler's angle and calcaneal height were within 20% of the contralateral foot while the posterior facet and CC joint had to be congruent with a step-off less than 2 mm. Several functional scores related to foot and ankle pathology were used to evaluate functional outcomes (American Orthopedic Foot and Ankle Score - AOFAS, Lower Extremity Functional Score - LEFS, Olerud and Molander Ankle Score - OMAS, Calcaneal Functional Scoring System - CFSS, Visual Analog Scale for pain – VAS) and were compared between anatomic and nonanatomic DIAFCs using Student's t-test. Demographic data and information about injury severity were collected for each patient. Among the 84 enrolled patients, 6 were excluded while 11 were lost to follow-up. Thirty-nine patients had a nonanatomic reduction while 35 patients had an anatomic reduction (47%). Baseline characteristics were similar in both groups. When we compared the injury severity as defined by the Sanders’ Classification, we did not find a significant difference. In other words, the nonanatomic group did not have a greater proportion of complex fractures. Anatomically reduced DIACFs showed significantly superior results at 12 months for all but one scoring system (mean difference at 12 months: AOFAS 3.97, p = 0.12; LEFS 7.46, p = 0.003; OMAS 13.6, p = 0.002, CFSS 7.5, p = 0.037; VAS −1.53, p = 0.005). Univariate analyses did not show that smoking status, worker's compensation or body mass index were associated with functional outcomes. Moreover, fracture severity could not predict functional outcomes at 12 months. This study showed superior functional outcomes in patients with a DIACF when an anatomic reduction is achieved regardless of the injury severity

Introduction. Leg length discrepancy (LLD) is a common sequalae of limb reconstruction procedures. The subsequent biomechanical compensation can be directly linked to degenerative arthritis, lower back pain, scoliosis and functional impairment. It becomes particularly problematic when >2cm, established as a clinical standard. This two-arm experimental study assesses how reliable an iPhone application is in the measurement of LLD at different distances in control and LLD patients. Materials and Methods. 42 participants were included in the study, divided evenly into 21 control and 21 LLD patients. A standardised measurement technique was used to obtain TMM and iPhone application measurements, taken at a distance of 0.25m, 0.50m and 0.75m. Results. The mean discrepancy of iPhone-based measurements in the control group was 1.57cm, 1.59cm and 2.19cm at 0.25m, 0.50m and 0.75m respectively. This compares to measurements in the LLD cohort with a mean discrepancy of 1.71cm, 1.85cm and 2.19cm. The overall mean discrepancy of iPhone data was 1.78cm in the control cohort compared to 1.92cm in the LLD cohort. Conclusions. Results suggest that the iPhone application can be used to identify clinically significant leg length discrepancies. At 0.75 metres anomalous results become more prevalent and the accuracy of the application appears to decline. The results also suggest the application is slightly more accurate in the control group, nevertheless, in distances up to 0.50 metres the mean discrepancy sits within the 2cm standard of clinically significant LLD

Radial head fractures are common and mainly require a functional conservative treatment. About 20% of patients will present an unsatisfactory final functional result. There is, however, little data allowing us to predict which patients are at risk of bad evolve. This makes it difficult to optimize our therapeutic strategies in these patients. The aim of this study is to determine the personal and environmental factors that influence the functional prognosis of patients with a radial head fracture. We realized over a 1-year period a prospective observational longitudinal cohort study including 125 consecutive patients referred for a fracture of the radial head in a tertiary trauma center. We originally collected the factors believed to be prognostic indicators: age, sex, socioeconomic status, factors related to trauma or fracture, alcohol, tobacco, detection of depression scale, and financial compensation. A clinical and radiological follow-up took place at 6 weeks, 3 months, 6 months, and 1 year. The main functional measurement tool is the Mayo Elbow Performance Score (MEPS) and the Disabilities of the Arm, Shoulder and Hand (DASH). 123 patients were included in the study. 114 patients required nonsurgical management. 102 patients completed the 1-year follow-up for the main outcome (89 for the DASH score). Two patients required an unplanned surgery and were excluded from analyses. At 1 year, the average MEPS was 96.5 (range, 65–100) and 81% of subjects had an excellent result (MEPS ≥90). The most constant factor to predict an unsatisfactory functional outcome (MEPS <90 or DASH >17) is the presence of depressive symptoms at the initial time of the study (P = 0.03 and P = 0.0009, respectively). This factor is present throughout the follow-up. Other observed factors include a higher socioeconomic status (P = 0.009), the presence of financial compensation (P = 0.027), and a high-velocity trauma (P = 0.04). The severity of the fracture, advanced age, female sex, and the nature of the treatment does not influence the result at 1 year. No factor has been associated with a reduction in range of motion. Most of the radial head fractures heal successfully. We identified for the first time, with a valid tool, the presence of depressive symptoms at the time of the fracture as a significant factor for an unsatisfactory functional result. Early detection is simple and fast and would allow patients at risk to adopt complementary strategies to optimize the result

Summary. The mathematical model has proven to be highly accurate in measuring leg length before and after surgery to determine how leg length effects hip joint mechanics. Introduction. Leg length discrepancy (LLD) has been proven to be one of the most concerning problems associated with total hip arthroplasty (THA). Long-term follow-up studies have documented the presence of LLD having direct correlation with patient dissatisfaction, dislocation, back pain, and early complications. Several researchers sought to minimize limb length discrepancy based on pre-operative radiological templating or intra-operative measurements. While often being a common occurrence in clinical practice to compensate for LLD intra-operatively, the center of rotation of the hip joint has often changes unintentionally due to excessive reaming. Therefore, the clinical importance of LLD is still difficult to solve and remains a concern for clinicians. Objective. The objective of this study is two-fold: (1) use a validated forward-solution hip model to theoretically analyze the effects of LLD, gaining better understanding of mechanisms leading to early complication of THA and poor patient satisfaction and (2) to investigate the effect of the altered center of rotation of the hip joint regardless LLD compensation. Methods. The theoretical mathematical model used in this study has been previously validated using fluoroscopic results from existing implant designs and telemetric devices. The model can be used to theoretically investigate various surgical alignments, approaches, and procedures. In this study, we analyzed LLD and the effects of the altered center of rotation regardless of LLD compensation surgeons made. The simulations were conducted in both swing and stance phase of gait. Results. During swing phase, leg shortening lead to loosening of the hip capsular ligaments and subsequently, variable kinematic patterns. The momentum of the lower leg increased to levels where the ligaments could not properly constrain the hip leading to the femoral head sliding from within the acetabular cup (Figure 1). This piston motion led to decreased contact area and increased contact stress within the cup. Leg lengthening did not yield femoral head sliding but increased joint tension and contact stress. A tight hip may be an influential factor leading to back pain and poor patient satisfaction. During stance phase, leg shortening caused femoral head sliding leading to decreased contact area and an increase in contact stress. Leg lengthening caused an increase in capsular ligaments tension leading to higher stress in the hip joint (Figure 2). Interestingly, when the acetabular cup was superiorized and the surgeon compensated for LLD, thus matching the pre-operative leg length by increasing the neck length of the femoral implant, the contact forces and stresses were marginally increased at heel strike (Figure 3). Conclusion and Discussion. Altering the leg length during surgery can lead to higher contact forces and contact stresses due to tightening the hip joint or increasing likelihood of hip joint separation. Leg shortening often lead to higher stress within the joint. Further assessment must be conducted to develop tools that surgeons can use to ensure post-operative leg length is similar to the pre-operative condition. For any figures or tables, please contact authors directly

Background. Occasionally, patients experience new or increased ankle pain following total knee arthroplasty (TKA). The aims of this study were to determine (1) how the correction of varus malalignment of the lower limb following TKA affected changes in alignment of the ankle and hindfoot, (2) the difference in changes in alignment of the ankle and hindfoot between patients with and without ankle osteoarthritis (OA), and (3) whether the rate of ankle pain and the clinical outcome following TKA differed between the 2 groups. Methods. We retrospectively reviewed prospectively collected data of 56 patients (99 knees) treated with TKA. Among these cases, concomitant ankle OA was found in 24 ankles. Radiographic parameters of lower-limb, ankle, and hindfoot alignment were measured preoperatively and 2 years postoperatively. In addition, ankle pain and clinical outcome 2 years after TKA were compared between patients with and without ankle OA. Results. The orientation of the ankle joint line relative to the ground improved from varus 9.4° to varus 3.4°, and the valgus compensation of the hindfoot for the varus tilt of the ankle joint showed a 2.2° decrease following TKA. Patients in the group with ankle OA showed decreased flexibility of the hindfoot resulting in less preoperative valgus compensation (p = 0.022) compared with the group without ankle OA. The postoperative hindfoot alignment was similar between the 2 groups because of the smaller amount of change in patients with ankle OA. The group with ankle OA had a higher rate of increased ankle pain (38% compared with 16%) as well as a worse Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score (mean of 22.2 compared with 14.2) following TKA. Conclusions. A considerable proportion of patients who underwent TKA had concomitant ankle OA with reduced flexibility of the hindfoot. These patients experienced increased ankle pain following TKA and a worse clinical outcome

Introduction. Primary robotic-arm assisted total hip arthroplasty (THA) yields more accurate and reproducible acetabular cup placement, nonetheless, data is scarce in terms of outcomes. The purpose of the present study was to report on patient-reported outcomes (PROMs) in a large group of patients who underwent robotic-arm assisted THA. The authors hypothesized that (1) patients who underwent robotic-arm assisted primary THA would achieve favorable and significant improvement in PROMs, (2) an accurate and reproducible acetabular cup placement with respect to the defined SafeZones would be obtained, and (3) a low rate of THA dislocation would be observed. Methods. Prospectively collected data were retrospectively reviewed between April 2012 to May 2017. Primary THA using Mako Robotic-Arm [Mako Surgical Corp. (Stryker), Fort Lauderdale, FL, USA] with minimum two-year follow-up for the Harris Hip Score (HHS) and the Forgotten Joint Score-12 (FJS-12) were included. Exclusion criteria were: bodymass index (BMI) > 40 kg/m2, age < 21-year old, worker's compensation, or unwilling to participate. Visual analog scale (VAS) for pain and patient satisfaction were obtained. Intraoperative measurements for leg-length, global offset, acetabular inclination and version were documented. Results. 501 hips were included (57.29% females), follow-up was 43.99 ± 15.59 months. Average age was 58.70 ± 9.41 years, and the BMI was 28.41 ± 4.55 kg/m2. The group reported HHS of 90.87 ± 13.45, FJS-12 of 79.97 ± 25.87, VAS of 1.20 ± 2.06, and patient satisfaction of 8.85 ± 2.08. Intraoperative values for acetabular inclination and version were 40.0° ± 2.2 ° and 20.5° ± 2.4° respectively. Revision due to instability was 0.2%. Conclusions. Patients who received primary robotic-arm assisted THA reported excellent results at 44-month follow-up for multiple PROMs. Consistency in acetabular cup placement accuracy was achieved in regard to the Lewinnek and Callanan safe-zones

Background. Total hip arthroplasty (THA) has been and continues to be the gold standard for treatment of end-stage osteoarthritis. With each year, implant characteristics are evolving to increase patient-reported outcomes and decrease complications. Purpose: to report minimum 2-year outcomes and complications in patients who underwent robotic-arm assisted THA using Corin versus Stryker-type implants. Methods. Data were prospectively collected on patients who underwent THA with Corin-type implants (both cup and stem) and THA using Stryker implants between June 2011 and July 2016. A 1:1 propensity match was performed using the following 5 covariates: age, body mass index, gender, Charlson score and smoking status. Surgical outcomes were assessed at minimum 2-year follow-up using the Forgotten Joint Score (FJS), Harris Hip Score (HHS), Veterans RAND 12-item physical and mental health survey, Short Form 12 physical and mental health survey, Visual Analog Score (VAS), and patient satisfaction. The exclusion criteria were previous hip condition/surgery, workers compensation, or were unwilling. Results. Of the eligible 774 cases, 645 patients (83.3%) had minimum 2-year follow-up and met inclusion and exclusion criteria. Of the 645 patients, 323 had Corin implants, and 155 had Stryker implants. The 1:1 propensity match successfully yielded 290 patients (145 per implant group) which had a minimum 2-year follow-up at a mean 38.3 months (range, 24.1–65.3 months). Average age was 59.9 (range, 34.92–79.89 Stryker group, 30.65–75.92 Corin group) for each group and average BMI were 30.0 (range, 19.05–49.33) kg/m. 2. for the Stryker group and 29.77 (range, 20.15–55.37) kg/m. 2. for the Corin group. FJS (P=0.0388) and patient satisfaction (P=0.0019) were significantly higher in the Stryker implant group than the Corin implant group. There were nine cases of postoperative thigh numbness or paresthesias, three cases of wound infection, and one case of nonunion in the Corin-implant group. There were four cases of postoperative thigh numbness or parasthesias and six cases of wound infection in the Stryker-implant group. Conclusion. At minimum 2-year follow-up, patients who had undergone THA with Stryker-type implants had significantly higher FJS and satisfaction and a trend toward decreased complications than patients with Corin-type implants. These results can help guide decision making for surgical instrumentation by arthroplasty surgeons

Introduction. The aim of the present study was to evaluate the discrepancies of rotational profiles of whole limb between operated and non-operated limb following unilateral total knee arthroplasty. Materials and Methods. We conducted an analysis the CT data from 32 patients undergoing primary unilateral total knee arthroplasty using measured resection technique, which femoral component was always implanted with external rotation to posterocondylar axis from July 2009 to April 2013. Using these CT scan, rotational profiles of total limb such as femoral torsion angle (femoral neck anteversion angle; FTA), tibial torsion angle (TTA), knee joint rotation angle (KJRA) and total limb rotation (TLR) were measured. Results. There were significant discrepancies of FTA and KJRA between operated and non-operated limb following unilateral total knee arthroplasty. The mean difference of operated and non-operated side for FTA and KJRA were −6.51 ± 11.88º (p=0.0041) and −6.83 ± 5.04º (p < 0.001) respectively. However, there were no significant discrepancies of TLR, TTA. TTA and TLR showed strong correlation (r= 0.7309). Conclusion. FTA showed significant side to side discrepancy, TTA and TLR showed no significant discrepancy between operated- and non-operated limbs in patients undergone unilateral TKA. These results are due to the compensation effect of KJRA. However, excessive external rotation of femoral component beyond the compensation effect of prosthetic knee joint can lead to total limb rotational discrepancy in patient undergoing unilateral total knee arthroplasty