The elevation of the joint line is considered a possible cause of mid-flexion instability in total knee arthroplasty (TKA). The authors evaluated the effects of joint line change on mid-flexion stability in cruciate retaining TKA. Seventy-nine knees treated by cruciate retaining TKA using a modified balanced gap technique were included in this prospective study. After prosthesis insertion, valgus and varus stabilities were measured under valgus and varus stress using a navigation system at 0, 30, 60 and 90° of knee flexion. Changes of joint lines were measured preoperatively and postoperatively and compared. The knees were allocated to a “No change group (≤4mm, 62 patients)” or to an “Elevation group (>4mm, 17 patients)”. Medio-lateral stabilities (defined as the sums of valgus and varus stabilities measured intra-operatively) were compared in the two groups. The mean joint line elevation was 4.6mm in the no change group and 1.7mm in the elevation group. Mean medio-lateral stability at 30° of knee flexion was 4.8±2.3 mm in the no change group and 6.3±2.7 mm in the elevation group, and these values were significantly different (p = 0.02). However, no significant differences in medio-lateral stability were observed at other flexion angles (p>0.05). Knees with a < 5mm joint line elevation provide better mid-flexion stability after TKA. The results of this study suggest that a < 5mm elevation in joint line laxity is acceptable for cruciate retaining TKA

Introduction. Wear debris from polyethylene tibial inserts has been associated with limited longevity of total knee replacements (TKRs). While material factors were studied extensively and considerable progress has been made, there is little knowledge about surgical factors, particularly on how the wear rate is related to implant positioning. It was the purpose of this study to determine the combined effect of patient and implant positioning factors on the volumetric wear rate of TKRs. Our hypothesis was that implant alignment has a significant impact on the wear rate when controlled for other patient factors. Methods. This study included 59 tibial inserts of a cruciate retaining TKR design (Nexgen, Zimmer Inc.). The patients' age, sex, weight, height, and implant size were obtained. All implants were scanned with a coordinate measuring machine. Volumetric wear was determined using an autonomous mathematical reconstruction method (Figure 1). Radiographs were used to determine the anatomic lateral distal femoral angle (aLDFA), anatomic medial proximal tibial angle (aMPTA), femoral tilt angle (FTA) and posterior tibial slope (PTS). Also, the patella position was assessed using the Blackburne-Peel Index (BPI) and the Insall-Salvati Ratio (Figure 2). General linear modeling (SPSS) was conducted in order to determine the most significant patient and implant positioning factors on wear rate. Results. After adjustment for creep, the mean volumetric wear rate was 11.6 mm. 3. /yr (Figure 2). According to the linear regression model wear increased with younger age (p=0.0014) and male sex (p<0.001). The wear rate was independent of patient weight (p=0.17). From the multiple positioning factors only BPI and tibial slope were significant and inversely correlated with wear (p=0.009 and 0.026, respectively). The average ISR was normal before and after surgery, whereas the BPI was only in the normal range prior to surgery, and dropped postop into pseudo-baja (p<0.001, Figure 3). Discussion. The effect of male sex on wear volume can partially be explained by a larger average implant size; however, other unknown confounding factors may play a role too. The effect of younger age is likely related to higher patient activity. Based on previous gait analysis, we speculate that increasing tibial slope results in larger AP translations of the knee joint and thus more wear. Interestingly, BPI remained a highly significant factor when controlled for all other factors. The average BPI clearly dropped post-operatively, whereas the average ISR did not, indicating that not true patella baja, but a joint line elevation occurred due to the reconstruction. Joint line elevation may affect the quadriceps mechanism leading to higher contact forces and subsequent higher wear. Post-operative joint line elevation can be explained by the intention to keep bone loss at a minimum, while using thick polyethylene inserts. Further studies are needed to determine the trade-offs between bone conservation and reduction of wear rate. However, this study has revealed the importance of surgical factors regarding polyethylene wear reduction in TKR. Acknowledgements. This study was funded by NIH grant R01AR059843. For figures/tables, please contact authors directly.

Introduction:. Acetabular revision Jumbo cups are used in revision hip surgeries to allow for large bone to implant contact and stability. However, jumbo cups may also result in hip center elevation and instability. They may also protrude through anterior wall leading to ilopsoas tendinitis. Methods:. The study was conducted using two methods:. Computer simulation study. 265 pelvic CT scans consisting of 158 males and 107 females were converted to virtual 3-dimensional bones. The average native acetabular diameter was 52.0 mm, SD = 4.0 mm (males in 52.4 mm, SD = 2.8 mm and 46.4 mm, SD = 2.6 mm in females). Images were analyzed by custom CT analytical software (SOMA™ V.3.2). 1. and over-sized reaming was simulated. Four distinct points, located in and around the acetabular margins, were used to determine the reamer sphere. Points 1, 2, 3 were located at the inferior and inferior-medial acetabular margins, and Point 4 was located superiorly and posteriorly in the acetabulum to simulate a bony defect in this location, Point 4 was placed at 10%, 20%, 30%, 40%, 50% and 60% of the distance from the superior – posterior margin of the acetabular rim to the sciatic notch to simulate bony defects of increasing size. (Figure 1). Radiographical study. Retrospective chart review of patient records for all cementless acetabular revisions utilizing jumbo cups between January 1, 1998 and March 30, 2012 at UCFS (98 patients with 57 men, 41 women). Jumbo cups: ≥66 mm in males; <62 mm in females. Reaming was directed inferiorly to the level of the obturator foramen to place the inferior edge of the jumbo cup at the inferior acetabulum. To determine the vertical position of the hip center, a circle was first made around both the jumbo and the contralateral acetabular surfaces using Phillips iSite PACS software. The center of this circle was assumed to correspond to the “hip center”. The height of the hip center was estimated by measuring the height of a perpendicular line arising from the interteardrop line (TL) and ending at the hip center. Results:. The computer simulation and radiographic analysis deomonstrated similar results. The computer simulation predicted that the hip center shifted superiorly and anteriorly as the reamer size increased. The hip center shifted 0.27 mm superiorly and 0.02 mm anteriorly for every millimeter in diameter increased for the reaming. (Figure 2) Anterior column bone removal was increased 0.86 mm for every 1 mm of reamer size increase. (Figure 3). Results of radiographical study is shown in Table bellow:. Discussion:. Use of a jumbo cup in revision THA results in elevation of the hip center. Therefore a longer femoral head may be needed to compensate for hip center elevation when a jumbo cup is used. Reaming for a jumbo cup can also result in loss of anterior bone stock and protrusion of the cup anteriorly which may cause iliopsoas tendonitis

Introduction. Optimal knee joint function obviously requires a delicate balance between the osseous anatomy and the surrounding soft tissues, which is distorted in the case of joint line elevation (JLE). Although several studies have found no correlation between JLE and outcome, others have linked JLE to inferior results. The purpose of this in vitro investigation was to evaluate the effect of JLE on tibiofemoral kinematics and collateral ligament strains. Materials and Methods. Six cadaver knees were equipped with reflective markers on femur and tibia and CT scans were made. A total knee arthroplasty (TKA) was performed preserving the native joint level. The knees were then tested in passive flexion-extension and squatting in a knee kinematics simulator while marker positions were recorded with an optical system. During squatting quadriceps forces were measured as well as tibio-femoral contact pressures. Finally, a revision TKA was performed with JLE by 4 mm. The femoral component was downsized and a thicker insert was used. The knees were again tested as before. Based on the bony landmarks identified in the CT scans and the measured trajectories of the markers, relative tibiofemoral kinematics could be calculated as well as distance changes between insertions of the collateral ligaments. Statistical tests were carried out to detect significant differences in kinematic patterns, ligaments elongation, tibiofemoral contact pressures and quadriceps forces between the primary TKA and after JLE. Results. Tibiofemoral kinematics are shown in Figure 1. For both passive flexion and squatting, tibial external rotation and adduction were similar before and after JLE. In passive flexion, JLE decreased the posterior translation of the femoral medial and lateral condyle centres, especially beyond 40 degrees of flexion. A slight 5% anterior shift of both centres was noted after JLE during squatting, but this was not significant. Strains in the collateral ligaments are shown in Figure 2. The collateral ligament lengths remained constant during passive flexion and were unaffected by elevation of the joint line. During squatting, the sMCL stretched with flexion after primary TKA and this behaviour stayed constant when the joint line was elevated. The LCL showed a similar loosening trend in both TKA configurations. Also tibiofemoral joint kinetics were not affected by JLE: quadriceps force and contact pressures all remained essentially unchanged during squatting before and after JLE. Discussion and conclusion. Although clinical observations have indicated that JLE is associated with inferior clinical results, the effects of JLE on knee biomechanics which might explain these outcomes remain relatively unknown. In this study, we specifically evaluated those effects on tibiofemoral kinematics and kinetics, as well as elongation of the collateral ligaments. As our current study did not detect any effect of JLE in tibiofemoral kinematics, kinetics, and strains of collateral ligaments in revision TKA, it is possible that these effects may be limited to or triggered at the patello-femoral joint, and more significant with higher joint line elevations than the 4-mm level tested in the current study. This hypothesis needs to be further investigated in future in-vitro and in-vivo studies

Accurate and reproducible measurement of three-dimensional shoulder kinematics would contribute to better understanding shoulder mechanics, and therefore to better diagnosing and treating shoulder pathologies. Current techniques of 3D kinematics analysis use external markers (acromial cluster or scapula locator) or medical imaging (MRI or CT-Scan). However those methods present some drawbacks such as skin movements for external markers or cost and irradiation for imaging techniques. The EOS low dose biplanar X-Rays system can be used to track the scapula, humerus and thorax for different arm elevation positions. The aim of this study is to propose a novel method to study scapulo-thoracic kinematics from biplanar X-rays and to assess its reliability during abduction in the scapular plane. This study is based on the EOS™ system (EOS Imaging, Paris, France), which allows acquisition of 2 calibrated, low dose, orthogonal radiographs with the subject standing at 30 to 40° angle of coronal rotation to the plane of one of the X-ray beams, in order to limit superimposition with the ribcage and spine. Seven abduction positions in the scapular plane were maintained by the subjects for 10 seconds, during X-ray acquisition. Between two positions, the subjects returned at rest position. Arm elevations were approximately 0, 10, 20, 30, 60, 90 and 150° (position 1 to 7). Six subjects were enrolled to perform a reproducibility study based on the 3D reconstructions of 2 experienced observers three times each. For each subject, a personalised 3D reconstruction of the scapula was created. The observer digitises clearly visible anatomical landmarks on both stereoradiographs for each arm position. These landmarks are used to make a first adjustment of a parameterised 3D model of the scapula. This provides a pre-personalised model of the subject's scapula which is then rigidly registered on each pair of X-rays until its retroprojection fits best on the contours that are visible on the X-rays. The thorax coordinate system (CS) was built following the ISB (International Society of Biomechanics) recommendations. The CS associated to the scapula was a glenoid centred CS based on the ellipse which fit on the glenoid rim on the 3D model of scapula. Scapular CS orientation and translation in the thorax CS was calculated following a Y,X,Z angle sequence for each position. Each 3D reconstruction of the scapula was performed in approximately 30 minutes. The most reproducible rotation was upward/downward rotation (along X axis) with a 95% confidence interval (95% CI) from 2.71° to 3.61°. Internal/external rotation and anterior/posterior tilting were comprised respectively between 5.18° to 8.01° and 5.50° to 7.23° (CI 95%). The most reproducible translation was superior-inferior translation (along Y axis) with a 95% CI from 1.22mm to 2.46mm. Translation along X axis (antero-posterior) and Z axis (medio-lateral) were comprised respectively between 2.49mm to 4.26mm and 2.47mm to 3.30mm (CI 95%). We presented a new technique for 3D functional quantitative analysis of the scapulo-thoracic joint. This technique can be used with confidence; uncertainty of the measures seems acceptable compared to the literature. Main advantages of this technique are the very low dose irradiation compared to the CT-Scan and the possibility to study arm elevation above 120°

Introduction. Higher concentrations of metal ion levels after Metal-on-metal (MoM) THA are a cause for concern. Elevated cobalt (Co) and chromium (Cr) ion levels in the blood indicate metal wear, and may predict secondary soft-tissue damage (adverse reaction to metal debris; ARMD). Although, it is well known that concentrations of metal ion levels are elevated in the short term after MoM, the long-term consequences in ion concentration and risk factors for increased ion levels are not clarified. We sequentially investigated the postoperative Co and Cr ion levels after MoM THA and the relationship between the metal ion levels and several risk factors. Materials and Methods. We reviewed the data on one hundred and eighty six patients of two hundred ninety one MoM THA cases. The one hundred eighty six patients were measured at least three times after a MoM THA surgery over a five year (2005–2010) period in our institution. Serum cobalt and chromium levels were measured by inductor coupled plasma – mass spectrometry at several times in follow-up period, (measured at the preoperative period, the third month, the sixth month, the first year, the second year, and the fourth year after MoM THA). Furthermore, we investigated the correlation between the metal ion levels and various factors which might influence the release of metal ions, such as Body mass index (BMI), renal function, femoral head size, unilateral or bilateral THA, the cup position, and postoperative activity. The renal function was evaluated by measuring estimated glomerular filtration ratio (GFR) at preoperative examination. A postoperative activity was assessed with a pedometer measurement counting number of steps a day. A cup position was evaluated by lateral inclination measured by X-ray or computed tomography. Results. Average serum Co and Cr concentrations in preoperative period were 0.69 and 0.05 mg/ ml, respectively. Postoperative serum Co and Cr ion levels were significantly increased compared with preoperative value throughout the postoperative period. There was no significant correlation with regards to BMI, renal function, femoral head size tothe metal ion level measurement. In bilateral THA cases, Co and Cr ion concentrations were significantly increased compared with unilateral THA cases. In addition, in cases that its cup inclination was more than 50 degrees, Co and Cr ion concentration were significantly increased compared with cases less than 50 degrees in the first year after surgery. There was a trend for higher metal ion levels in the group of patients who walked more than 7000 steps a day, but this did not reach statistical significance. Conclusion. Metal ion concentrations of almost patients were increased after MoM THA surgery. Side effects related to elevation of serum Co or Cr concentration were currently not identified and overall clinical results were good. However, Longer follow-up would be necessary if the patients have overlapping risk factors, because those patients may experience elevation of the level in postoperative late stage

Purpose. While reverse shoulder arthroplasty (RSA) corrects vertical muscle imbalance, it cannot restore the horizontal imbalance seen in cuff-deficient shoulders with combined loss of active elevation and external rotation (CLEER). We report the medium-term results of the modified latissimus dorsi/teres major tendon transfer (L'Episcopo procedure) associated with RSA, performed via a single deltopectoral approach. Method. Sixteen CLEER patients underwent the procedure and were followed up at a mean of 49 months (range, 36–70). All patients had lost spatial control of their arm, were unable to maintain neutral rotation, and had abnormal infraspinatus and teres minor muscles on imaging. Outcome measures included Constant score (CS), Subjective Shoulder Value (SSV), and ADLER score (activities of daily living requiring external rotation). Results. Fifteen patients were satisfied or very satisfied. There were significant improvements (p<0.05) in active elevation (72 degrees to 139 degrees), active external rotation (−24 degrees to 4 degrees), CS (27 to 64), ADLER score (5.0 to 23.8) and SSV (23% to 77%). Active internal rotation decreased from 6 to 3 points. Scapular notching was observed in 3 patients and spurs in 3 patients. One deep infection required two-stage revision of the prosthesis and the patient was disappointed with the result. One patient required reoperation (arthrolysis and acromioclavicular joint excision). Conclusion. Reverse shoulder arthroplasty combined with the modified L'Episcopo procedure improves shoulder function in patients with CLEER. Patients regain spatial control of their arm. The observed internal rotation loss has led us to modify the surgical technique by fixing the transferred tendons more posteriorly on the humerus

Introduction

Wear and corrosion of metal-on-metal (MM) bearings releases (a) soluble metal ions which collect locally and pass into the systemic circulation and (b) insoluble particles which undergo local deposition and lymphoreticular dissemination. Debris-related failures from osteolysis, metallosis and pseudotumours warrants revision of these MM bearing devices to non-MM bearing arthroplasties with the expectation that both the systemic and local effects will be reversed with time since the source of metal ion release is removed.

The purpose of the present study is to determine (a) whether metal ion levels in blood and urine decrease after revision of a MM bearing arthroplasty to a non-MM bearing device and (b) the rate at which this decrease is effected.

Introduction. There is no doubt that the future of limb lengthening lies with internal lengthening. Complication rates are reduced and patient satisfaction is increased. The evolution of internal lengthening peaked with the dual direction, easily inserted and externally controlled PRECICE Nail. It has excelled in performance in accuracy and satisfaction. Its versatility increased with smaller sizes and increased excursion. A field safety notice was issued was issued in October 2021 by the parent company NuVasive. The advice was monitoring of current cases and a hold on implantation until after a review of process. At the National Orthopaedic Hospital Cappagh we elected to remove all implanted nails and assess the nail integrity and physiological changes associated with implantation. Materials & Methods. All patients in who a retained Precice nail at the time of the field safety notice were identified. Patients and families were contacted to explain the issued safety notice from the company and explain that we would be scheduling them for nail removal. This was part of our standard care but we prioritised this group on our waiting list. Consent was obtained for nail removal but also for histological assessment of canal scrapings, blood ion level analysis and independent assessment of the retrieved nail by our academic collaborators at University College Dublin. Ion levels were then repeated at an interval post removal with consent. Results. We identified 7 Precice nails in 5 patients still implanted. All patients had consolidated after lengthening and were ready for nail removal. Elevated Titanium blood ion levels were identified at the time of retrieval. Histological abnormalities consistent with metalosis were identified. In all cases the nail was grossly intact and examination of the motor showed no evidence of wear or failure. Follow up ion levels obtained post retrieval showed persistent elevation. Conclusions. Our retrieval audit shows persistent elevation of Titanium ion levels and abnormal histology despite apparent nail integrity. These findings require further evaluation in a larger retrieval series to determine if there is a high incidence of this phenomenon and if ion levels have a clinical effect

Patients awaiting resolution of swelling and oedema prior to ankle surgery can represent a significant burden on hospital beds. Our study assessed whether external pneumatic intermittent compression (EPIC) can reduce delays to surgery. Our prospective randomised controlled trial (n= 20) compared outcomes of patients treated with EPIC vs control group managed with ice and elevation. Included were patients aged <18 years with isolated closed ankle fractures admitted for management of swelling prior to surgery. Excluded were open fractures, injuries to contralateral leg, diabetes, absent pulses, peripheral vascular disease, inability to consent, no requirement for admission. Eligible patients were randomised to active or control arms. All patients were managed initially with reduction and back slab application. Patients in active arm fitted with EPIC (Hydroven 3000) device over the back slab. Assessment by treating team determined the time at which patient is assessed ready for surgery. Patients in the treatment arm were assessed as ready for surgery sooner, (123 hrs vs 168hrs, T score = 1.925, P 0.035) and had a shorter time to surgery (167 hrs vs 216 hrs, T score = 1.748, P 0.047) Length of stay was reduced bud did not reach statistical significance. (259 hrs vs 269 hrs, T score 0.229, P 0.41). Our results showed a statistically and clinically significant reduction in time that patients were assessed ready for surgery and time to surgery in the treatment cohort. We conclude that although further data is needed to achieve an adequately powered study and assess the safety profile of the EPIC, incorporation of EPIC into routine clinical practice has the potential for significant cost savings

This paper presents an ongoing review of the use of a wedge-shaped porous metal augments in the shoulder to address glenoid retroversion as part of anatomical total shoulder arthroplasty (aTSA). Seventy-five shoulders in 66 patients (23 women and 43 men, aged 42 to 85 years) with Walch grade B2 or C glenoids underwent porous metal glenoid augment (PMGA) insertion as part of aTSA. Patients received either a 15º or 30º PMGA wedge (secured by screws to the native glenoid) to correct excessive glenoid retroversion before a standard glenoid component was implanted using bone cement. Neither patient-specific guides nor navigation were used. Patients were prospectively assessed using shoulder functional assessments (Oxford Shoulder Score [OSS], American Shoulder and Elbow Standardized Shoulder Assessment Form [ASES], visual analogue scale [VAS] pain scores and forward elevation [FE]) preoperatively, at three, six, and 12 months, and yearly thereafter, with similar radiological surveillance. Forty-nine consecutive series shoulders had a follow-up of greater than 24 months, with a median follow-up of 48 months (range: 24–87 months). Median outcome scores improved for OSS (21 to 44), ASES (24 to 92), VAS (7 to 0), and FE (90º to 140º). Four patients died, but no others were lost to follow-up. Apart from one infection at 18 months postoperatively and one minor peg perforation, there were no complications, hardware failures, implant displacements, significant lucency or posterior re-subluxations. Radiographs showed good incorporation of the wedge augment with correction of glenoid retroversion from median 22º (13º to 46º) to 4º. All but four glenoids were corrected to within the target range (less than 10º retroversion). The porous metal wedge-shaped augments effectively addressed posterior glenoid deficiency as part of aTSA for rotator cuff intact osteoarthritis, producing satisfactory clinical outcomes with no signs of impending future failure

Introduction. Surgeons commonly resect additional distal femur during primary total knee arthroplasty (TKA) to correct a flexion contracture to restore range of motion and knee function. However, the effect of joint line elevation on the resulting TKA kinematics including frontal plane laxity is unclear. Thus, our goal was to quantify the effect of additional distal femoral resection on passive extension and mid-flexion laxity. Methods. Six computational knee models with capsular and collateral ligament properties specific to TKA were developed and implanted with a contemporary posterior-stabilized TKA. A 10° flexion contracture was modeled by imposing capsular contracture as determined by simulating a common clinical exam of knee extension and accounting for the length and weight of each limb segment from which the models were derived (Figure 1). Distal femoral resections of 2 mm and 4 mm were simulated for each model. The knees were then extended by applying the measured knee moments to quantify the amount of knee extension. The output data were compared with a previous cadaveric study using a two-sample two-tailed t-test (p<0.05) [1]. Subsequently, varus and valgus torques of ±10 Nm were applied as the knee was flexed from 0° to 90° at the baseline, and after distal resections of 2 mm, and 4 mm. Coronal laxity, defined as the sum of varus and valgus angulation in response to the applied varus and valgus torques, was measured at 30° and 45°of flexion, and the flexion angle was identified where the increase in laxity was the greatest with respect to baseline. Results. With 2 mm and 4 mm of distal femoral resection, the knee extended an additional 4°±0.5° and 8°±0.75°, respectively (Figure 2). No significant difference was found between the extension angle predicted by the six models and the results of the cadaveric study after 2 mm (p= 0.71) and 4 mm (p= 0.47). At 2 mm resection, mean coronal laxity increased by 3.1° and 2.7° at 30° and 45°of flexion, respectively. At 4 mm resection, mean coronal laxity increased by 6.5° and 5.5° at 30° and 45° of flexion, respectively (Figures 3a and 3b). The flexion angle corresponding to the greatest increase in coronal laxity for 2 mm of distal resection occurred at 22±7° of flexion with a mean increase in laxity of 4.0° from baseline. For 4 mm distal resection, the greatest increase in coronal laxity occurred at 16±6° of flexion with a mean increase in laxity of 7.8° from baseline. Conclusion. A TKA computational model representing a knee with preoperative flexion contracture was developed and corroborated measures from a previous cadaveric study [1]. While additional distal femoral resection in primary TKA increases passive knee extension, the consequent joint line elevation induced up to 8° of additional coronal laxity in mid-flexion. This additional midflexion laxity could contribute to midflexion instability; a condition that may require TKA revision surgery. Further studies are warranted to understand the relationship between joint line elevation, midflexion laxity, and instability. For any figures or tables, please contact the authors directly

Introduction. Frame HI is the #Days for device removal/cm. IM Nail HI is less relevant (31–45 D/cm). Albizzia HI was 33 D/cm (1991–2003). Patients felt fine approximately 1M after end of lengthening (EoL), resuming normal life and sports. This sometimes resulted in implants fractures (e.g. skying before bone fusion). Ideally, the full fusion should occur at the EoL. We decided to shorten the HI to reach this target, optimising all parameters. Materials & Methods. The evolution of care has been monitored over a 32-year clinical experience with a fully weight-bearing nails (Albizzia then G-nail). Monitoring was with X-rays, DEXA, blood bone activity, and in London with special 5G CBCT Scans. We implemented several changes in the Care of patients and measured them according to the ‘Five Principles’ (stability, function, ‘Roads-vascular supply’, ‘Materials-calories’ and ‘Workers-BFC’, with actions on food intake, activity levels and on muscle and bone vascular growths. Results. Preop: training (vascularity, muscle force). Op & Postop: spine morphine, IM sawing preserving BFC, controlled hypo-pressure, low hydration, 50 cm leg elevation, walking, resistance bike, full motion (drainage, muscle reactivation), discharge 3–4h postop (including bilateral). Postop daily intense gym training. POD07-21: Distraction increased to fight non-linear hyper-ossification (44–50 mm gain at POD30) +/- aided by NSAIDs. HI decreased to 12–20D/cm, sometimes 8D/cm with some ‘soft fusion’ during lengthening, hardening within 1W after EoL. Conclusions. The surgeon is not a passive X-rays observer, but has an active role in changing the healing speed and decreasing HI for patient safety. Electro/Magnetic nails (torque 1 Nm) may be clocked by bone fusion, which does not occur with the G-Nail (19 Nm). An holistic vision for patients and treatments at several levels is essential to accelerate bone healing, and to return fast to full normal life, after a short ‘lengthening parenthesis’

Introduction. Reverse total shoulder arthroplasty (RTSA) can partially restore lost range of motion (ROM). Active motion restoration is largely a function of RTSA joint constraint, limiting impingement, and muscle recruitment; however, it may also be a function of implant design. The aim of this computational study was to examine the effects of implant design parameters, such as neck-shaft (N-S) angle and glenoid lateralization, on impingement-free global circumduction range of motion (GC-ROM). GC-ROM summarizes the characteristically complex, wide-ranging envelope of glenohumeral motion into a single quantity for ease of comparison. Methods. Nine computational models were used to investigate implant parameters. The parameters examined were N-S angles of 135°, 145°, and 155° in combination with glenoid lateralizations (0, 5, and 10 mm). Static positioning of the humerus was defined by an elevation direction angle, elevation angle, and rotation. The humerus was rotated from the neutral position (0° of rotation and elevation), and then elevated in different elevation directions until impingement was detected. Abduction occurred at an elevation direction angle of 0°, while flexion and extension occurred at elevation direction angles of 90° and −90°, respectively. Elevation direction angles ranged from −180° to 180°. Elevation ranged from 0° and 180°. Rotations ranged from −45° to 90°, where negative and positive rotations represented external and internal rotation, respectively. For each rotation angle, a plot of maximum elevation in each elevation plane was created using polar coordinates (radius = elevation, angle = elevation direction). The area enclosed by the resulting points, normalized with respect to the implant with a 145° N-S angle and 5 mm lateralization, was calculated. The sum of these areas defined the GC-ROM. Results. Figure 1 depicts the maximum ROM curves at each angle of rotation for a 145° N-S angle humeral implant with 5 mm of glenoid lateralization. Table 1 shows the normalized areas within the maximum ROM curves for each implant configuration at each angle of rotation, where 0% indicates that the corresponding angle of rotation could not be achieved without impingement. The effect of varying N-S angle (constant lateralization of 5 mm) and lateralization (constant N-S angle of 145°) is shown for 0° rotation (Figures 2A and 2B, respectively). Conclusions. In general, increasing glenoid lateralization increases GC-ROM; however, the unintuitive poor performance of all 10 mm lateralized configurations at rotations of −90° highlights the complex relationships between implant parameters and ROM. Interestingly, the 135° N-S implant had greater flexion and extension ROM, while the 155° N-S implant had greater abduction ROM, suggesting that there are trade-offs between N-S angles pertaining to the elevation direction in which maximum elevation is obtained. The results of this study highlight the need to incorporate multi-directional motion when assessing the effect of varying implant parameters on the impingement-free GC-ROM. Future studies will include the application of the presented technique to a broader range of implant and surgical parameters

Displaced proximal humerus fractures remain a difficult clinical problem, and techniques as diverse as percutaneous pinning, locked plating, intramedullary nailing, and shoulder arthroplasty have been proposed. In recent years, reverse total shoulder arthroplasty (RTSA) has become a very popular option to fix just about any fracture. However, RTSA is not without risk, with complications ranging from infection, instability, acromial stress fractures, aseptic loosening, notching and more. In a 2017 study on 39 patients, Tokish et al. compared non-operative treatment to reverse shoulder arthroplasty for displaced 3- and 4-part fractures. There was no difference in pain, range of motion or outcome scores between the two groups. Among the patients who underwent RTSA, there was no difference between early (<30 days) and late (>30 days) surgery suggesting that it could be safe to attempt a non-operative trial in most patients and see how they do. This is also supported by a 2016 study by Sanchez-Sotelo et al. in which they compared 18 patients with primary RTSA to 26 patients with failed ORIF who underwent salvage RTSA. There was no difference in ASES score, ROM and overall satisfaction between both groups suggesting that an ORIF can be attempted in many patients without the fear of compromising a revision RTSA. And although RTSA may provide more predictable results, in a properly selected patient, a well-executed hemiarthroplasty can outperform an RTSA. In a study from Molé et al., 38 patients were randomised to either RTSA or to a hemiarthroplasty. In the hemiarthroplasty group, half of the patients had <90 degrees of forward elevation and half the patients had >120 degrees of forward elevation showing a bi-modal distribution dependent on tuberosity healing. In the RTSA group, however, while having an average of 115 degrees of forward elevation, 68% of patients had less than 120 degrees of forward elevation. While RTSA is a great tool to treat complex displaced comminuted fractures in elderly patients with poor bone quality, it should not be blindly applied to all fractures types and all patients

Shoulder arthroplasty, both primary (TSA) and reverse (RTSA), are common interventions for arthritis and cuff tear arthropathy. The effect of shoulder arthroplasty on shoulder motion is of particular interest in assessing the effectiveness of the procedure and the development and biomechanical testing of implants. A comparison of the arthroplasty shoulder to that of the non-operated contralateral shoulder provides insight into how well the reconstruction has restored natural shoulder motion. The purpose of this study was to ascertain the shoulder motion of patients who have undergone shoulder arthroplasty and to compare the motion of the reconstructed and contralateral natural sides. Eleven human subjects (70±9yrs) who had undergone total shoulder arthroplasty wore a custom instrumented shirt for the waking hours of one day. The 3D orientation of each humeral sensor was transformed with respect to the torso to allow for the calculation of humeral elevation and plane of elevation angles. Joint angles for each subject were then discretised, and the operative and contralateral normal (control) shoulders were then compared. The majority of both the arthroplasty and control shoulder elevation motions took place below 80° of elevation, totaling on average 1910±373 and 1887±312 motions per hour, respectively. Conversely, elevations greater than 80° were significantly less with occurrences totaling only 55±31 and 78±41 motions per hour for the arthroplasty and control shoulders, respectively (p<0.01). Both the arthroplasty and control shoulder were at elevations below 80° for 88±7% and 87±7% of the day, respectively. When the total motion of the arthroplasty and non-operative control shoulders were compared, no statistically significant difference was detected (p=0.8), although the non-operated side exhibited marginally more motion than the operated side, an effect which was larger at higher elevation angles (p=0.3). This study provides insight into the effects of shoulder arthroplasty on thoraco-humeral motion and compares it to the non-operative side. Interestingly, there were no significant differences measured between the arthroplasty and the control side, which may demonstrate the effectiveness of reconstruction on restoring natural shoulder motion. It is interesting to note that on average, each shoulder arthroplasty elevated above 80° approximately 55 times per hour, corresponding to just under 330,000 motions per year. Similarly, when elevations greater than 60° are extrapolated, the resulting yearly motions total approximately 1.5 million cycles (Mc), which suggests that the ‘duty cycle’ of the shoulder is similar to the hip, approximated to be between 1–2 Mc per year. Arthroplasty wear simulators should be calibrated to simulate these patterns of motion, and component design may be improved by understanding the kinematics of actual shoulder motion

There are a variety of sizes currently available for reverse total shoulder arthroplasty (RTSA) implant systems. Common sizing options include a smaller 36 to 38 mm or a larger 40 to 42 mm glenosphere, and are typically selected based on surgeon preference or patient size. Previous studies have only evaluated the abduction and adduction range of motion within a single plane of elevation, providing a limited view of the joint's possible range of motion. The purpose of this study was to use computer modeling to evaluate the abduction and adduction range of motion across multiple planes of elevation for a range of glenosphere sizes. Computed tomography images of four cadaveric specimens (age: 54 ± 24 years) were used to obtain the osseous anatomy to be utilised in the model. Solid-body motion studies of the RTSA models were constructed with varying glenosphere diameters of 33, 36, 39, 42, and 45 mm in Solidworks (Dassault Systems, US). The implant components were scaled, while maintaining a consistent centre of rotation. Simulations encompassing the full range of abduction and adduction were conducted for the planes of elevation between −15˚ and 135˚ at 15˚ intervals, with the motion of the humerus being constrained in neutral internal-external rotation throughout all planes. Angles of elevation were obtained utilising the humeral long axis and the RTSA centre of rotation. Statistical analysis was performed using repeated measures ANOVA. Glenosphere diameter was found to significantly affect the adduction range of motion (p=0.043), in which the largest size provided approximately 17˚ more adduction range of motion than the smallest. However, abduction range of motion was not found to be significantly affected through the alteration of glenosphere size (p=0.449). The plane of elevation was not found to significantly affect abduction or abduction (p=0.585 & p=0.225, respectively). Increasing glenosphere diameter resulted in an increased adduction range of motion when averaged across the tested planes of elevation; however the observed influence on abduction was not significant. These are similar to the trends observed in the previous single plane of elevation studies. These findings illustrate the importance of implant sizing related to range of motion. Further studies are required to determine the influence of glenosphere size on internal and external range of motion

Background. Post-operative (postop) lower limb alignment in unicompartmental knee arthroplasty (UKA) has been reported to be an important factor for postop outcomes. Slight under-correction of limb alignment has been recommended to yield a better clinical outcomes than neutral alignment. It is useful if the postop limb alignment can be predicted during surgery, however, little is known about the surgical factors affecting the postop limb alignment in UKA. The purpose of this study was to examine the influence of the medial tibial joint line elevation on postop limb alignment in UKA. Methods. Seventy-four consecutive medial UKAs were enrolled in this study. All the patients received a conventional fixed bearing UKA. Pre-operative (preop) and postop limb alignment was examined using long leg radiograph and lower limb alignment changes were calculated. Femoral and tibial osteotomy thickness were measured during surgery. Medial tibial joint line change was defined as polyethylene thickness minus tibial osteotomy thickness and sawblade thickness (1.27mm). Positive values indicated a tibial joint line elevation. Medial femoral joint line change was defined as femoral distal component thickness (6.5mm) minus femoral distal osteotomy thickness and sawblade thickness. Positive values indicated a femoral joint line reduction. Medial joint distraction width was also calculated by tibial joint line elevation plus femoral joint line reduction. The correlation of lower limb alignment change with polyethylene insert thickness, the medial tibial joint line elevation, femoral joint line reduction, or joint distraction width were analyzed. Results. The mean preop hip-knee-ankle (HKA) angle was 7.1 ± 3.3° in varus and postop was 2.1 ± 3.0° in varus. The mean lower limb alignment change was 5.0 ± 2.6°. The mean polyethylene insert thickness was 8.5 ± 0.8mm, the tibial joint line elevation was 4.4 ± 1.3mm and the medial femoral joint line reduction was 0.0 ± 1.1mm, the joint distraction width was 4.5 ± 1.5mm. The polyethylene insert thickness, the medial tibial joint line elevation, and the joint distraction width were positively correlated with the lower limb alignment change (R=0.27; P<0.05, R=0.47; P<0.001, R=0.53; P<0.001, respectively) (Figure 1a,b,d). There was no correlation between the medial femoral joint line reduction and the lower limb alignment change (Figure 1c). Discussion. The postop limb alignment in total knee arthroplasty (TKA) is determined by the osteotomy angle of the femur and tibia. On the other hand, it has been reported that the postop alignment in UKA is not influenced by the osteotomy angle but by the insert thickness. Our results indicated that the medial tibial joint line elevation and the joint distraction width were more useful to predict lower limb alignment change than the insert thickness itself. Measuring the medial tibial osteotomy thickness during surgery will help surgeon to predict postop lower limb alignment in UKA. For any figures or tables, please contact authors directly (see Info & Metrics tab above).

Latissimus dorsi anterior to major transfers have been advocated in the setting of loss of external rotation and elevation in conjunction with reverse shoulder replacement. Reverse shoulder replacement is a prosthesis specifically designed for shoulders with poor rotator cuff function. In the vast majority of cases, some teres minor function at the minimum is maintained in shoulders destined for a reverse shoulder replacement. However, in certain circumstances there is complete loss of any external rotation, and a muscle transfer can be performed in order to restore some external rotation function. A reverse shoulder replacement in the absence of any rotator cuff function goes into obligate internal rotation with elevation. A minimum of external rotation strength is necessary in order to maintain the arm in normal rotation. The first tip is patient selection. Physical examination of active external rotation, external rotation strength and forward elevation should be just performed. A latissimus transfer is indicated in patients who cannot maintain their arm in neutral to at least a few degrees of external rotation. A lag sign is another physical examination finding which can indicate complete loss of rotator cuff function. The latissimus dorsi transfer is performed by first identifying and releasing the latissimus from its insertion on the anterior humerus. The arthroplasty is performed. The passage for the latissimus muscle is developed carefully and being mindful of the axillary nerve in particular. The latissimus is directed inferior to the nerve and around the medial and posterior aspect of the proximal humerus. Different ways of securing the transfer to the humerus have been described including bone tunnels and anchors. Often it is easier to place the anchors and/or the bone tunnels prior to inserting the humeral prosthesis. The latissimus is secured in the new position, enabling it to participate in external rotation. The value of this is difficult to clearly establish. Most studies are evidence level IV and there are no good comparative studies in a controlled patient population. This is a good option for shoulders with no active external rotation, but they may increase overall complication rate. Complications include dislocation, infection, and transient nerve palsy

Introduction. Acromial and scapular fractures are a rare but difficult complication with reverse total shoulder arthroplasty (rTSA), with an incidence rate reported from 1–10%. The risk factors associated with these fractures types is largely unknown. The goal of this study is to analyze the clinical outcomes, demographic and comorbidity data, and implant sizing and surgical technique information from 4125 patients who received a primary rTSA with one specific prosthesis (Equinoxe, Exactech, Inc) and were sorted based on the radiographic documentation of an acromial and/or scapula fracture (ASF) to identify factors associated with this complication. Methods. 4125 patients (2652F/1441M/32 unspecified; mean age: 72.5yrs) were treated with primary rTSA by 23 orthopaedic surgeons. Revision and fracture reverse arthroplasty cases were excluded. The radiographic presence of each fracture was documented and classified using the Levy classification method. 61 patients were identified as having ASF, 10 patients had fractures of the Type 1, 32 patients had Type 2, and 18 patients had Type 3 fractures according to Levy's classification. One fracture was not classifiable. Pre-op and post-op outcome scoring, ROM as well as demographic, comorbidity, implant, and surgical technique information were evaluated for these 61 patients and compared to the larger cohort of patients to identify any associations. A two-tailed, unpaired t-test identified differences (p<0.05). Results. The overall rate of ASF was 1.48% with the average time after surgery occurring at 12.9 ± 17.9 months (range 1 day to 78 months). Men had an ASF rate of 0.69% (10 of 1441); whereas women had a rate of 1.92% (51 of 2652). Patients with ASF were observed to be significantly shorter than patients without ASF (65.1 in vs 63.3 in, p=0.0004). ASF were more common in females (p=0.0019), have Rheumatoid Arthritis (p=0.0051), Cuff Tear Arthropathy (p=0.0093), or previous shoulder surgery (p=0.0189). Patient's weight did not correlate, nor did BMI. No difference was observed in humeral stem size, glenosphere diameter, or the humeral tray offset, humeral liner offset, or combined humeral tray+liner offset. The average number of screws used in the fracture group was significantly more than in the non-fracture group (p=0.0327), and 93% of patients in the fracture group had a screw in the superior hole of the baseplate. Pre-operatively, patients who developed ASF had significantly worse ASES (p=0.0104) and SPADI (p=0.0136) scores and also had significantly worse forward elevation (p=0.0237) and internal rotation (p=0.0054) than those who did not develop ASF. At latest follow-up, patients with ASF had significantly worse SST, UCLA, ASES, Constant, and SPADI scores (all p<0.0001); significantly worse abduction, forward elevation, internal rotation, strength (all p<0.0001); and significantly less preop-to-postop improvement in all measured outcomes, except for external rotation (all p<0.0001). Finally, 24% of fractures were identified as being caused by a traumatic event, 28% of patients with fractures had a previous acromioplasty, and 53% of fractures were Levy type 2. Discussion. Acromial and scapular fractures after rTSA are a rare complication, with an incidence of 1.48% in this analysis of 4125 patients with a single rTSA prosthesis. These fractures were observed to occur at an average of 12.9 months after surgery, but were observed as early as 1 day and as late as 6.5 years. Female patients, Rheumatoid Arthritis, Cuff Tear Arthropathy, previous shoulder surgery, relatively worse pre-operative ASES or SPADI scores, relatively decreased pre-operative forward elevation and internal rotation as well as a larger number of screws placed in the baseplate all were significantly associated with the occurrence of ASF. Although 93% of patients with ASF had a screw placed in the superior hole of the baseplate, we cannot conclude that this is a driving factor at this time, as the superior screw number for the non-fracture group was not recorded. Future work should evaluate if usage of a superior glenoid baseplate screw and previous acromioplasty are also risk factors for these fracture types after rTSA. This study is the largest ever performed analysis of this rare complication and provides news insight into the predisposing risk factors to consider when evaluating patients for rTSA