Introduction. The objective of our study was to determine the extent to which the quality of the biomechanical reconstruction when performing hip replacement influences gait performances. We aimed to answer the following questions: 1) Does the quality of restoration of hip biomechanics after conventional THR influence gait outcomes? (question 1), and 2) Is HR more beneficial to gait outcomes when compared with THR? (question 2). Methods. we retrospectively reviewed 52 satisfied unilateral prosthetic hip patients (40 THRs and 12 HRs) who undertook objective gait assessment at a mean follow-up of 14 months. The quality of the prosthetic hip biomechanical restoration was assessed on standing pelvic radiograph by comparison to the healthy contralateral hip. Results. We were unable to detect any statistically significant correlation between the radiographical parameters and the gait data, for THR patients. In stress conditions (inclination or declination of the ramp), the gait was more symmetric in the HR group, compared to the THR group. Discussion/Conclusions. We found that slight variations in the quality of the hip biomechanical restoration had little effect on gait outcomes of THR patients, and HR generated a more physiological gait under stress conditions than well-functioning THR

Background. Postoperative dislocation is one of the main surgical complications and the primary cause for revision surgery after 2-stage implant exchange due to periprosthetic infection of a total hip arthroplasty. Objective. The aims of our study were (1) to determine the incidence of dislocation after two-stage THA reimplantation without spacer placement, (2) to evaluate relevant risk factors for dislocation and (3) to assess the final functional outcome of those patients. Method. We prospectively analyzed 187 patients who underwent a two-stage total hip arthroplasty (THA) revision after being diagnosed with periprosthetic joint infection (PJI) from 2013 to 2019. The mean duration of follow-up was 54.2 ± 24.9 months (>36 months). The incidence of postoperative dislocation and subsequent revision was estimated through Kaplan-Meier curves and potential risk factors were identified using Cox hazard regression. The functional outcome of the patients was assessed using the modified Harris Hip Score (mHHS). Results. The estimated cumulative dislocation-free survival was 87.2% (95% CI: 81.2%-91.3%) with an estimated 10% and 12% risk for dislocation within the first 6 and 12 months, respectively. The use of a dual-mobility construct had no significant impact on the dislocation rate. Increasing body mass index (BMI) (HR=1.11, 95% CI: 1.02-1.19, p=0.011), abductor mechanism impairment (HR=2.85, 95% CI: 1.01-8.01, p=0.047), the extent of elongation of the affected extremity between stages (HR=1.04, 95% CI: 1.01-1.07, p=0.017), the final leg length discrepancy (HR=1.04, 95% CI: 1.01-1.08, p=0.018) and PJI recurrence (HR=2.76, 95% CI: 1.00-7.62, p=0.049) were found to be significant risk factors for dislocation. Overall revision rates were 17% after THA reimplantation. Dislocated hips were 62% more likely to undergo re-revision surgery (p<0.001, Log-rank= 78.05). A significant average increase of 30 points in mHHS scores after second-stage reimplantation (p=0.001, Wilcoxon-rank) was recorded, but no difference was noted in the final HHS measurements between stable and dislocated hips. Conclusion. Dislocation rates after 2-stage THA reimplantation for PJI remain high, especially regarding overweight or re-infected patients. Careful leg length restoration and an intact abductor mechanism seem critical to ensure stability in these complex patients

INTRODUCTION. The restoration of the anatomical hip rotation center (HRC) has a major influence on the longevity of hip prostheses. Deviations from the HRC of the anatomical joint after total hip arthroplasty (THA) can lead to increased hip joint forces, early wear or loosening of the implant. The contact conditions of acetabular press-fit cups after implantation, including the degree of press-fit, the existence of a polar gap and cup orientation, may affect the HRC restoration, and therefore implant stability. The aim of this study was to determine the influence of acetabular press-fit, polar gap and cup orientation on HRC restoration during THA. METHODS. THAs were performed by an experienced orthopaedic surgeon in full cadaveric models simulating real patient surgery (n=7). Acetabular cups with a Porocoat™ (n=3) and Gription™ surface coating (n=4) were implanted (DePuy Synthes, Leeds, UK). Computed tomography (CT) scans prior to surgery, as well as after reaming and implantation of press-fit cups were used to calculate the HRC displacement. After aligning the pelves in the anterior pelvic plane, 3D reconstruction of the HRC at each stage was performed by fitting spheres to the femoral head, the reamed cavity and the inserted cup. 3D surface models of the cups were generated using a laser scanner and were registered to the CT images. The effective press-fit was calculated using the diameters of spheres, fitted to the cavity prior to cup insertion and to the outer cup coating. The polar gap was defined as the difference between the outer cup surface and the subchondral bone at the cup pole. Anteversion and abduction angles were calculated as difference between the cup planes and the sagittal and transverse plane, respectively. RESULTS. A medial (6.4±1.6mm), superior (5.1±1.5mm) and posterior (3.0±1.4mm) displacement of the HRC after reaming was measured. A significant inferior shift of the HRC could be measured after cup implantation (p=0.043). No significant influence of the coating design on the HRC shift could be observed. The shift of the HRC back towards the anatomical HRC was highly correlated to the degree of polar gap (R. 2. =0.928, p<0.001) and a trend towards an association with effective press-fit was observed (R. 2. =0.536, p=0.061). The cup angles had no influence on the shift of the HRC, but a high variability in cup anteversion (20.7° to 61.8°) was observed. DISCUSSION. The study suggests that increasing the press-fit and polar gap improves the restoration of the anatomical HRC. Since increasing the degree of press-fit could also lead to higher stresses and an increased fracture risk, future work will study how the acetabular contact conditions influence both primary implant stability and fracture risk, in order to establish an optimal HRC reconstruction to maximize implant longevity

Proper restoration of posterior condylar offset during TKA has been shown to be important to maximize range of motion and minimize flexion instability. However, there is little information as to the importance of restoration of mid-sagittal femoral geometry. There is controversy as to whether a TKA prosthesis should have a single radius or multiple radii of curvature. The purpose of this study is to evaluate the effectiveness of a multi-radius femoral component at restoring mid sagittal femoral offset. A consecutive series of 100 TKAs with digital preoperative and postoperative radiographs and standardized radiographic markers were analyzed. There were 71 female and 29 male knees with mean age of 59 years. All TKAs were performed by a single surgeon using a multi-radius femoral component design. The distal femoral resection was set to resect 10 mm from the distal femoral condyle and a posterior referencing system was used to size the femoral component. Using radiographic perfect lateral projections of the knees, a line was drawn along the posterior femoral shaft and another parallel line down the anterior femoral shaft. A 3rd line was then drawn parallel to the posterior shaft at the furthest point posterior on the condyle. A 4th line was drawn parallel to the anterior shaft at the furthest point anterior on the femur. 90 degree angles were constructed to create a grid in the anterior and posterior directions, similar to a previously reported technique. Finally, 45 degree angle lines were created in the grid to assess mid flexion dimensions [Fig-1 and 2]. The percent change in posterior condylar offset (PCO), anterior femoral offset (AFO), mid femoral anterior offset (MAFO) and mid femoral posterior offset (MFPO) were calculated. The mean reproduction of the mid-anterior femoral offset and mid-posterior femoral offset were 101.1% [range 56.5%–167.5%] and 96.8% [range 54.9%–149.0%] of preoperative measurements respectively. The average restoration of posterior offset and anterior offset were 92.8% [range 49.0%–129.8%] and 115.3% of preoperative measurements [range 35.7%–400.0%] respectively. When the posterior condylar offset was restored to within 10% of the native anatomy, the MPFO restoration more closely resembled normal anatomy (103.0% vs. 93.9%, p = 0.005). When the postoperative posterior condylar offset was decreased greater than 20%, both the MAFO (90.1% vs. 104.5%, p = 0.004) and MPFO (78.5% vs. 102.9%, p < 0.001) decreased compared to the native knee. There was no relationship between restoration of the PCO and the MAFO correction (104.6% vs. 99.4%, p = 0.213). Finally, there was no correlation between restoration of anterior femoral offset within 10% of normal and the restoration of mid sagittal femoral offset; 98.0% vs 102.0% for MAFO (p = 0.320) and 98.7% vs 96.3% for MPFO (p = 0.569). A modern multi-radius condylar knee design is capable of reproducing the mid-sagittal geometry of the preoperative knee. However, the restoration of mid sagittal offset is largely dependent on the restoration of the posterior condylar offset. Intraoperative adjustments in anterior and posterior femoral resections can have significant impact in the ability of the implant to reproduce mid-sagittal femoral anatomy

Abstract. Objective. Radial to axillary nerve and spinal accessory (XI) to suprascapular nerve (SSN) transfers are standard procedures to restore function after C5 brachial plexus dysfunction. The anterior approach to the SSN may miss concomitant pathology at the suprascapular notch and sacrifices lateral trapezius function, resulting in poor restoration of shoulder external rotation. A posterior approach allows decompression and visualisation of the SSN at the notch and distal coaptation of the medial XI branch. The medial triceps has a double fascicle structure that may be coapted to both the anterior and posterior division of the axillary nerve, whilst preserving the stabilising effect of the long head of triceps at the glenohumeral joint. Reinnervation of two shoulder abductors and two external rotators may confer advantages over previous approaches with improved external rotation range of motion and strength. Methods. Review of the clinical outcomes of 22 patients who underwent a double nerve transfer from XI and radial nerves. Motor strength was evaluated using the MRC scale and grade 4 was defined as the threshold for success. Results. 18/22 patients had adequate follow-up (Mean: 29.5 months). Of these, 72.2% achieved ≥grade 4 power of shoulder abduction and a mean range of motion of 103°. 64.7% achieved ≥grade 4 external rotation with a mean range of motion of 99.6°. Conclusions. The results suggest the use of the combined nerve transfer for restoration of shoulder function via a posterior approach, involving the medial head branch of triceps to the axillary nerve and the XI to SSN

Abstract. Aim. With resumption of elective spine surgery services following the first wave of COVID-19 pandemic, we conducted a multi-centre BASS collaborative study to examine the clinical outcomes of surgeries. Methods. Prospective data was collected from eight spinal centres in the first month of operating following restoration of elective spine surgery following the first wave. Primary outcomes measures were the 30-day mortality rate and postoperative Covid-19 infection rate. Secondary outcomes analysed were the surgical, medical adverse events and length of inpatient stay. Results. 257 patients (128 Male) with an age range of 2–88 years formed the study cohort. The average workload from each unit was 32(range 16–101) with 118 procedures (46%) done as category 3 prioritisation level (Procedures performed in < 3 month). 87% of patients were low-medium “risk stratification” category. 195 patients (75.8%) isolated for two weeks preoperatively and all but four patients had COVID-19 negative test prior to surgery. None of the patients were diagnosed with COVID-19 infection nor was any mortality related to COVID-19 in the 30 day follow up period, with 25 patients having been tested for symptoms. 32 patients (12%) developed a total of 34 complications with 19/34 being grade 1–2 Clavien-Dindo classification of surgical complications. Median LOS 5.2 days and 78.4 % patients stayed less than a week. Conclusions. As per our study safe and effective planned spinal surgical services can be restored avoiding viral transmission, with adherence to national guidelines and COVID-secure pathways tailored according to the resources of the individual spinal units

Purpose. The positon of short stem is affected by the native anatomy of femoral neck and also by fixation mechanism dependent on design. As a consequence, it has been speculated that restoration of hip geometry might be limited in total hip arthroplasty (THA) using short stem. Therefore, the present study assessed the predictability of restoration of hip geometry using two different CCD-angled short stem engaging the lateral cortex. Materials and Methods. The 60 patients included 15 females and 45 males. The average age was 48.0 years with average BMI 24.2. Biomechanical parameters of hip geometry were analysed on postoperative calibrated radiographs in 30 consecutive primary unilateral THAs using short stem (Metha®, B. Braun Aesculap, Tuttlingen, Germany) with 120° CCD angle (group I) and 30 match controlled cases with 135° CCD angle (group II) and compared to those of the contralateral hip without deformity. The matching process was done before collecting the radiographic measurements by two blinded observer and was for sex, age ± 5 years, and BMI ± 7 units in that order. Results. Head length was short in 40%, 67%, medium in 37%, 23% and large in 23%, 10% of the patients in each group respectively with no significant difference in between group (p=0.11). The discrepancies of horizontal hip center of rotation (△HHCR) and the vertical hip center of rotation (△VHCR) compared to the contralateral side was similar in both groups (p=0.95, p= 0.11, respectively), which enabled to make a direct comparison of the femoral reconstruction. Compared to the contralateral side, discrepancies of limb length (△LLD) showed a borderline significant difference between two groups (avr.+0.7mm, +2.5mm respectively, p=0.04) with higher values for group of 135° CCD angle (more than 5mm of LLD in 27%). However, in group of 120° CCD angle, the discrepancies of horizontal femoral offset (△HFO) and abductor lever arm (△AbLA) (avr. +5.9 mm, +4.9mm respectively) revealed significantly increased compared with balanced value of group 135° CCD angle (+0.9mm, p <0.0001, +1.3mm, p=0.02, respectively) and about half of patients in group of 120° CCD angle revealed outside the 5mm difference target in either horizontal femoral offset (53% of patient) and abductor lever arm (50% of patient). Conclusion. With decreasing CCD-angle of short stem, restoration of limb length appears more predictable but, horizontal femoral offset and abductor lever arm increased with outside of a beneficial range. This tendency should be taken into consideration when choice the design of this kind of neck-preserving short stem as well as exact implantation technique

Today controversy exists whether restoration of neutral mechanical alignment should be attempted in all patients undergoing TKA. The restoration of constitutional rather than neutral mechanical alignment may in theory lead to a more physiological strain pattern in the collateral ligaments, and could therefore potentially be beneficial to patients. It was therefore our purpose to measure collateral ligament strains during three motor tasks in the native knee and compare them with the strains noted after TKA in different postoperative alignment conditions. Six cadaver specimens were examined using a validated knee kinematics rig under physiological loading conditions. The effect of coronal malalignment was evaluated by using custom made tibial implant inserts in order to induce different alignment conditions. The results indicated that after TKA insertion the strains in the collateral ligaments resembled best the preoperative pattern of the native knee specimens when constitutional alignment was restored. Restoration to neutral mechanical alignment was associated with greater collateral strain deviations from the native knee. Based upon this study, we conclude that restoration of constitutional alignment during TKA leads to more physiological periarticular soft tissue strains during loaded as well as unloaded motor tasks

Introduction. Potential implant and technique related factors to improve patellofemoral (PF) kinematics in total knee arthroplasty (TKA) are design of trochlear geometry and patella, restoration of posterior offset, patellar tilt and avoid overstuffing. The primary aim of this prospective, matched pair study was to assess the radiographic features of PF kinematics with an anatomic patella. Material and Methods. Between July 2012 and May 2013, 49 consecutive posterior stabilized cemented Attune TKAs (Depuy Synthes Warsaw Indiana) were matched to the 49 PFC Sigma (Depuy) based on age, gender, and body mass index (BMI). All surgeries were performed via medial parapatellar approach with patellar resurfacing. Radiographic analysis was performed prospectively with minimum 1-year follow-up and included overall limb alignment, anterior offset, posterior offset, joint line, patellar thickness, patellar tilt and patellar displacement by two independent observers. Results. We found significant improvement in all post-operative radiographies parameters from prior to surgery, however, there was no significance between the two groups (Table 1). Posterior offset and joint line were restored in all cases and no overstuffing of the PF joint was seen. Discussion. At minimum one-year follow-up, anatomical patella has excellent safety and efficacy with restoration of the PF kinematics. Metalized design of the Attune anatomic patella component allows better contact with trochlear groove and improves tilt with lateralization of the patella

Purpose. The ultimate goal in total hip arthroplasty is not only to relieve the pain but also to restore original hip joint biomechanics. The average femoral neck-shaft angle(FNSA) in Korean tend to have more varus pattern. Since most of conventional femoral stems have relatively high, single, fixed neck shaft angle, it's not easy to restore vertical and horizontal offset exactly especially in Korean people. This study demonstrates the advantages of dual offset(especially high-offset) stem for restoring original biomechanics of hip joint during the total hip arthroplasty in Korean. Materials and Methods. 180 hips of 155 patients who underwent total hip arthroplasty using one of the standard(132°) or extended(127°) offset Accolade cementless stems were evaluated retrospectively. Offset of stem was chosen according to the patient's own FNSA in preoperative templating. In a morphometric study, neck-shaft angle of proximal femur, vertical offset and horizontal offset, abductor moment arm were measured on preoperative and postoperative both hip AP radiographs and the differences and correlation of each parameters, between operated hip and original non-operated hip which had no deformity (preoperative ipsilateral or postoperative contralateral hip), were analyzed. Results. The standard stems were used in 34 hips and extended offset stems were used in 146 hips. The FNSA of non-operated hip was an average of 129.8°(127.2°□135.8°) in standard group and mean 125.4°(122.7°□129.9°) in extended offset group. The FNSA of operated hip was an average of 131.6° and 127.1° in each group. In the statistical analysis, there was no significant difference of mean horizontal and abductor moment arm between operated hip and non-operated hip in both groups and the restoration of horizontal offset and abductor moment arm showed(p=0.217, p=0.093) significant positive correlation(R=0.870, R=0.851) to the original value. However, vertical offset was increased an average of 1.4mm in operated hip and there was statistical significance. Restoration of vertical offset showed positive correlation to original value (R=0.845). Conclusion. Dual- or multi-offset stem, especially extended offset stem can provide easy restoration of hip biomechanics and soft tissue tension without significant alteration of leg length especially in Korean with more varus femoral neck compared to Caucacian. Precise radiographic measurements of original hip and application of proper-offset stem should be taken in order to restore ideal hip biomechanics successfully and easily. A use of a proper offset stem can afford to enhance joint stability and implant longevity by improving soft-tissue tension and reducing resultant force, and it will guarantee a successful results after total hip arthroplasty in the aspect of function and longevity

Introduction. While implant designs and surgical techniques have improved in total knee arthroplasty (TKA), approximately 20% of patients remain dissatisfied. The purpose of this study was to determine if reproduction of anatomic preoperative measurements correlated to improved clinical outcomes in TKA. Methods. We retrospectively reviewed95 patients (106 knees) who underwent a TKA between 2012 −2013 with a minimum of one year follow-up. All patients had a pre and post-operative SF-12 and WOMAC scores. Pre and 6 week post-operative radiographs were reviewed to compare restoration of coronal plane alignment, maintenance of joint line obliquity, and maintenance of tibial varus. Coronal alignment was defined as the angle formed between the mechanical axis of the femur and the the tibia. Joint line obliquity was defined as the angle between the mechanical axis of the limb and the line which best parallels the joint space at the knee. Tibial varus was compared between the preoperative proximal lateral tibial angle and the angle formed by the mechanical axis of the tibia and tibial component postoperatively. Results. In 106 patients, postoperative coronal alignment, maintenance of tibia varus, or restoration of joint line obliquity did not correlate to improved outcomes. Patients with residual varus coronal alignment of more than 2° had increased pain and total WOMAC scores (p=0.013 and p = 0.036). Patients who had under-correction of the native tibial angle, had an increase in overall WOMAC score (p=0.007) with increased pain (p=0.012), stiffness (p=0.038), and function (p = 0.001). Furthermore, over-correction of tibial angle resulted in increased WOMAC functional scores (p=0.019), but was not significant to the overall WOMAC. Conclusions. In this study, restoration of a patient's native tibial varus correlated to improved WOMAC scores at 1 year postoperatively. Undercorrection of varus resulted in worse total WOMAC scores whereas overcorrection resulted in worse WOMAC functional scores

Background. Posterior referencing (PR) total knee arthroplasty (TKA) aims to restore posterior condylar offset. When a symmetric femoral implant is externally rotated (ER) to the posterior condylar axis, it is impossible to anatomically restore the offset of both condyles. PR jigs variously reference medially, laterally, or centrally. The distal femoral cutting jigs typically reference off the more distal medial condyle, causing distal and posterior resection discrepancies. We used sawbones to elucidate differences between commonly used PR cutting jigs with regards to posterior offset restoration. Materials/Methods. Using 32 identical sawbones, we performed distal and posterior femoral resections using cutting guides from 8 widely available TKA systems. 6 systems used a central-referencing strategy, 1 system used a lateral-referencing strategy, and 1 system used a medial-referencing strategy with implants of asymmetric thickness. Distal femoral valgus resection was set at 5 degrees for all specimens. Rotation was set at 3 degrees for 2 sawbones and 5 degrees for 2 sawbones with each system. We measured the thickness of all bone resections, and compared those values to known implant thickness. Results. Central- and lateral-referenced systems with symmetric implants showed distal lateral under-resection. The medial-referenced system with asymmetric implants restored the anatomic joint line medially and laterally. Central-referenced systems showed close to 1mm (SD ±0.2) postero-lateral offset over-restoration and postero-medial offset under-restoration at 3 degrees of ER, and a 1.6mm change in each offset at 5 degrees of ER. The lateral-referenced system demonstrated a 1.7mm mismatch between the distal-medial and the postero-medial resections at 3 degrees of rotation. There was a 3.9mm mismatch at 5 degrees of ER. Medial-referenced systems demonstrated a mismatch between the distal-lateral and postero-lateral resections, present only with 5 degrees of ER. Conclusion. Our data offers insight for arthroplasty surgeons into the bony resections taken by widely used TKA instrumentation systems. The lateral-referenced jigs reduced the postero-medial offset by 4 degrees at 5 degrees, a difference on the order of 1 to 2 femoral sizes depending on the implant system. The medial-referenced system, with the use of asymmetric condylar thicknesses, restored condylar anatomy within 1mm in the majority of circumstances. When set at 5 degrees of external rotation, over-restoration of the postero-lateral femoral offset occurred. Center-referenced systems resulted in minor changes in offset at 3 degrees of rotation, but a decrease in the postero-medial offset by 2mm at 5 degrees of external rotation. The distal femoral cutting jig typically restores the medial joint line in extension when there is minimal medial wear. Referencing laterally in flexion may introduce a discrepancy between the extension and flexion gaps. Available medial- and lateral-referenced jigs provide the option of shifting the bony resections anteriorly or posteriorly and adjusting the sizing as needed

Restoration of the native joint line in total knee arthroplasty is important in restoring ligamentous balance and normal knee kinematics. Failure to achieve this could lead to reduced range of motion, patellofemoral maltracking and suboptimal outcomes. The purpose of this study was to analyse the clinical and functional outcome of patients who demonstrated joint line changes after computer-assisted (CAS) total knee arthroplasty (TKA). A prospective study was conducted for 168 patients (168 knees) who underwent CAS TKA by two surgeons at a single institution with an average follow-up of two years. The final change in joint line was calculated from the verified tibial resection, distal and posterior femoral cuts. Group A patients had joint line changes of less than 4mm and Group B patients had joint line changes of more than 4mm. Postoperative Oxford scores, Knee scores, Function scores and SF-36 scores were obtained at six months, one year and two years post-TKA. The final range of motion and the mechanical alignment were documented. There was significant linear correlation between joint line changes and Oxford scores (p = 0.05) and Function scores (p = 0.05) at six months and Oxford scores alone at two years with increasing joint line changes having poorer outcome scores. Group A compared to Group B patients have better outcomes in terms of Oxford scores (mean 20 vs 27, p = 0.0003), Function scores (mean 69 vs 59, p = 0.03), SF-1 (mean 63 vs 50, p = 0.03), SF-2 (mean 66 vs 43, p = 0.05), SF-5 (mean 75 vs 63, p = 0.04), SF-6 (mean 84 vs 59, p = 0.003), SF-7 (mean 96 vs 83, p = 0.02), SF-8 (mean 84 vs 73, p = 0.006) and total SF-36 scores (mean 603 vs 487, P = 0.003), at six months, and Oxford scores (mean 18 vs 23, p = 0.0007) at two years. In this study, CAS is a useful intra-operative tool for assessing the final joint line in TKA. Outliers in joint line changes of ≥ 4 mm are associated with poorer clinical outcome scores

INTRODUCTION. Leg length discrepancy following total hip arthroplasty (THA) can be functionally disabling for affected patients and can lead on to litigation issues. Assessment of limb length discrepancy during THA using traditional methods has been shown to produce inconsistent results. The aim of our study was to compare the accuracy of navigated vs. non navigated techniques in limb length restoration in THA. METHODS. A dataset of 160 consecutive THAs performed by a single surgeon was included. 103 were performed with computer navigation and 57 were non navigated. We calculated limb length discrepancy from pre and post op radiographs. We retrieved the intra-operative computer generated limb length alteration data pertaining to the navigated group. We used independent sample t test and descriptive statistics to analyse the data. RESULTS. The two subgroups were matched for age, diagnosis and preoperative leg length discrepancy. The mean age was 69.12 (37–89, SD-8.3) and the mean BMI was 29 (19–44, SD-5.03). The mean post op limb length discrepancy in the non navigated group was 5 mm (SD-6) as compared to mean of 3.5mm (SD-6.5) for the computer navigated group. This difference was statistically significant (p<0.04). 18% of patients in the non navigated group had a limb length discrepancy of >10 mm as compared to 12% in the navigated group. There was no statistically significant difference between the computer predicted leg length alterations and those measured on radiographs. (p>0.15). DISCUSSION & CONCLUSION. The use of Computer navigation in THA can be useful in reducing errors related to leg length discrepancy. It helps in reducing the rates of unacceptably high discrepancies. In our experience, the results of this technique were predictable and reproducible. We intend to continue using this tool for our total hip arthroplasties

Introduction

Accurate evaluation of femoral offset is difficult with conventional anteroposterior (AP) X-rays. Routine CT imaging is costly and exposes patients to a significant dose of radiation. The EOS® imaging system is an innovative slot-scanning radiography system that makes possible the acquisition of simultaneous and orthogonal AP and lateral images of the patient in standing position. These 2-dimensional (2D) images are equivalent to standard plane X-rays. Three-dimension (3D) reconstructions are obtained from these paired images according to a validated protocol. This prospective study explores for the first time the value of the EOS® imaging system for comparing measurements of femoral offset obtained from 2D images and 3D reconstructions.

Introduction

Revision hip arthroplasty with massive proximal femoral bone loss remains challenging. Whilst several surgical techniques have been described, few have reported long term supporting data. A proximal femoral allograft (PFA) may be used to reconstitute bone stock in the multiply revised femur with segmental bone loss of greater than 8 cm. This study reports the outcome of largest case series of PFA used in revision hip arthroplasty.

A primary goal of revision Total Knee Arthroplasty (rTKA) is restoration of the Joint Line (JL) and Posterior Condylar Offsets (PCO). The presence of a native contralateral joint allows JL and PCO to be inferred in a way that could account for patient-specific anatomical variations more accurately than current techniques. This study assesses bilateral distal femoral symmetry in the context of defining targets for restoration of JL and PCO in rTKA. 566 pre-operative CTs for bilateral TKAs were segmented and landmarked by two engineers. Landmarks were taken on both femurs at the medial and lateral epicondyles, distal and posterior condyles and hip and femoral centres. These landmarks were used to calculate the distal and posterior offsets on the medial and lateral sides (MDO, MPO, LDO, LPO respectively), the lateral distal femoral angle (LDFA), TEA to PCA angle (TEAtoPCA) and anatomic to mechanical axis angle (AAtoMA). Mean bilateral differences in these measures were calculated and cases were categorised according to the amount of asymmetry. The database analysed included 54.9% (311) females with a mean population age of 68.8 (±7.8) years. The mean bilateral difference for each measure was: LDFA 1.4° (±1.0), TEAtoPCA 1.3° (±0.9), AAtoMA 0.5° (±0.5), MDO 1.4mm (±1.1), MPO 1.0mm (±0.8). The categorisation of asymmetry for each measure was: LDFA had 39.9% of cases with <1° bilateral difference and 92.4% with <3° bilateral difference, TEAtoPCA had 45.8% <1° and 96.6% <3°, AAtoMA had 85.7% <1° and 99.8% <3°, MDO had 46.2% <1mm and 90.3% <3mm, MPO had 57.0% <1mm and 97.9% <3mm. This study presents evidence supporting bilateral distal femoral symmetry. Using the contralateral anatomy to obtain estimates for JL and PCO in rTKA may result in improvements in intraoperative accuracy compared to current techniques and a more patient specific solution to operative planning

Aims. Bacterial infection activates neutrophils to release neutrophil extracellular traps (NETs) in bacterial biofilms of periprosthetic joint infections (PJIs). The aim of this study was to evaluate the increase in NET activation and release (NETosis) and haemostasis markers in the plasma of patients with PJI, to evaluate whether such plasma induces the activation of neutrophils, to ascertain whether increased NETosis is also mediated by reduced DNaseI activity, to explore novel therapeutic interventions for NETosis in PJI in vitro, and to evaluate the potential diagnostic use of these markers. Methods. We prospectively recruited 107 patients in the preoperative period of prosthetic surgery, 71 with a suspicion of PJI and 36 who underwent arthroplasty for non-septic indications as controls, and obtained citrated plasma. PJI was confirmed in 50 patients. We measured NET markers, inflammation markers, DNaseI activity, haemostatic markers, and the thrombin generation test (TGT). We analyzed the ability of plasma from confirmed PJI and controls to induce NETosis and to degrade in vitro-generated NETs, and explored the therapeutic restoration of the impairment to degrade NETs of PJI plasma with recombinant human DNaseI. Finally, we assessed the contribution of these markers to the diagnosis of PJI. Results. Patients with confirmed PJI had significantly increased levels of NET markers (cfDNA (p < 0.001), calprotectin (p < 0.001), and neutrophil elastase (p = 0.022)) and inflammation markers (IL-6; p < 0.001) in plasma. Moreover, the plasma of patients with PJI induced significantly more neutrophil activation than the plasma of the controls (p < 0.001) independently of tumour necrosis factor alpha. Patients with PJI also had a reduced DNaseI activity in plasma (p < 0.001), leading to a significantly impaired degradation of NETs (p < 0.001). This could be therapeutically restored with recombinant human DNaseI to the level in the controls. We developed a model to improve the diagnosis of PJI with cfDNA, calprotectin, and the start tail of TGT as predictors, though cfDNA alone achieved a good prediction and is simpler to measure. Conclusion. We confirmed that patients with PJI have an increased level of NETosis in plasma. Their plasma both induced NET release and had an impaired ability to degrade NETs mediated by a reduced DNaseI activity. This can be therapeutically restored in vitro with the approved Dornase alfa, Pulmozyme, which may allow novel methods of treatment. A combination of NETs and haemostatic biomarkers could improve the diagnosis of PJI, especially those patients in whom this diagnosis is uncertain. Cite this article: Bone Joint J 2024;106-B(9):1021–1030

Custom 3D printed implants can be anatomically designed to assist in complex surgery of the bony pelvis in both orthopaedic oncology and orthopaedic reconstruction surgery. This series includes patients who had major pelvic bone loss after initially presenting with tumours, fractures or infection after previous total hip arthroplasty. The extent of the bone loss in the pelvis was severe and therefore impossible to be reconstructed by conventional ‘off –the-shelve’ implants. The implant was designed considering the remaining bony structures of the contra-lateral hemi- pelvis, to provide an anatomical, secured support for the reconstructed hip joint. The latter was realised by strategically orientated screws and by porous structures (an integral part of the implant), which stimulates osseointegration. A custom pelvic implant was designed, manufactured and 3D printed. Reconstruction of the pelvis was performed together with a cemented (bipolar bearing) acetabular cup. In some cases, a proximal femoral replacement was also necessary to compensate for bony defects. All patients had sufficient range of motion (ROM) at the hip with post-operative stability. It has been verified, at six and twelve months postoperatively, that there is a strong hold of the implant due to osseointegration. Additionally, in patients whose posterior acetabular wall was missing, it was discovered that the implant assisted in bone formation and covered the entire posterior surface of the implant. All patients in this study managed with this novel treatment option, proved to have a stable pelvic reconstruction with restoration of leg lengths, improvement of strength and independent ambulation at short and medium term follow-up

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