Background. Long term success of any shoulder joint reconstruction procedure involving subscapularis attachment take down is dictated by the way one chooses to release and repair/reconstruct the subscapularis insertion. There are several methods that were reported in the literature without any preset guidelines which are easily reproducible. Methods. 5 specimens of fresh cadaver shoulder joints dissected and the subscapularis footprint insertion involving the tendon and muscle exposed. We intend to preserve subscapularis tendon footprint along with the lesser tuberosity by performing the footprint osteotomy fashioned step wise in the following manner. Results. It has two vertical components (sagittal and coronal plane osteotomies) and one horizontal component (distal osteotomy at musculo tendinous junction level). Figure 1: demonstrating the three step cuts in the dry bone of proximal humerus with three different ostetomes to mark the plain of osteotomies in the lesser tuberosity. Step-1: Medial wall ridge of the inter-tubercular sulcus serves as landmark for sagittal component. The depth of sagittal component is just 5 – 10mm and its length extending from articular margin proximally and distally up to musculo tendinous junction, measuring approximately 15–20mm. Step-2: Coronal plane osteotomy is in line with and parallel to undersurface of subscapularis tendon adjacent to the articular margin and connecting sagittal component and measured 10–15mm approximately. Figure 2: demonstrating the two cuts / osteotomies to mark the sagittal and coronal components of the subscapularis foot print osteotomy in the lesser tuberosity of a fresh cadaver. Step-3: The horizontal component (distal osteotomy at musculo tendinous junction level is 5–10 mm in width, connects the two vertical components, thus completing the footprint osteotomy. Discussion. Subscapularis reattachment plays a pivotal role in the shoulder joint reconstruction procedures especially total joint arthroplasty. Subscapularis take down either by tenotomy or by periosteal elevation from lesser tuberosity followed by repair carries a risk of retraction and poor healing and early failure. Footprint osteotomy as a thin sliver of cortical bone instead of these above described three steps with the attached tendon carries a risk of fragmentation of the bone sliver along with lack of rotation control on the repair. The necessity for doing such a three step osteotomy procedure which results in a wedge shaped bone tendon foot print construct, we believe is of paramount importance for a successful reconstruction. Figure 3: demonstrating the marking sutures passed into the bone tendon construct comprising of lesser tuberosity and subscapularis for effective foot print reconstruction in a fresh cadaver. Conclusions. This three step footprint osteotomy of the Subscapularis tendon offers a stable construct which is easy to reproduce with better healing potential. For figures, please contact authors directly

Introduction. Accurate alignment of components in total knee arthroplasty (TKA) is a known factor that contributes to improvement of post-operative kinematics and survivorship of the prosthetic joint. Recently, CAOS has been introduced into TKA in effort to reduce positioning variability that may deviate from the mechanical axis. However, literature suggests that clinical outcomes following TKA with CAOS may not present a significant improvement from traditional methods of implantation. This would infer that achieving correct alignment, alone, might be insufficient for ensuring an optimal reconstruction of the joint. Therefore, this study seeks to evaluate the importance of soft-tissue balancing, through the quantification of joint kinetics collected with intraoperative sensors, with or without the combined use of CAOS. Methods. Seven centers have contributed 215 patients who have undergone primary TKA with the use of intraoperative sensors. Of the 7 surgeons contributing patients to this study, 3 utilize CAOS; 4 utilize manual techniques. Along with standard demographic and surgical data being collected as per the multicenter study protocol, soft-tissue release techniques and medial-lateral intercompartmental loads—as indicated by the intraoperative sensors—were also captured pre- and post-release. “Optimal” balance was defined as a medial-lateral load difference of ≤ 15 lbs. A chi-squared analysis was performed to determine if the percentage of soft-tissue release was significantly different between the two groups: patients with CAOS, and patients without CAOS. Results. Of the 215 patients (35% with CAOS, 65% without CAOS) who have received TKA, using intraoperative sensors to assess mediolateral balance, 92.6% underwent soft-tissue release. Stratifying this data by surgical technique: 89% of the patients with CAOS, and 94% of patients without CAOS, were released. A chi-squared analysis—with 3 degrees of freedom; and 99% confidence—was executed to determine if the 5% difference between the two groups was significant. The analysis showed that there was no significant difference between the two groups, thus we can conclude that soft-tissue release is as equally necessary in the CAOS TKA group, as it is in the traditional TKA group. Discussion. It is widely accepted that correct alignment of TKA components contributes to improved kinematic function of the affected joint. Recently, technology has been developed to digitally guide surgeons through bony cuts, thereby decreasing the incidence of deviation from the mechanical axis. However, alignment may not be the foremost contributing factor in ensuring an optimal joint state. In this evaluation, 92.6% of the cohort required some degree of releasing of ligamentous structures surrounding the knee joint, regardless of intraoperative technique used. A chi-squared analysis of the data supports the claim that soft-tissue release is used in nearly all cases, irrespective of the use of CAOS (p < 0.001). This suggests that soft-tissue release is necessary in nearly all cases, even after appropriate alignment has been digitally verified. The data strongly supports the idea that obtaining an optimally functioning joint is multifactorial, and that alignment may play a more minor role in achieving ideal joint reconstruction than previously assumed, being superseded by the necessity to achieve soft-tissue balance

The Adams-Berger reconstruction is an effective technique for treating distal radioulnar joint (DRUJ) instability. Graft preparation techniques vary amongst surgeons with insufficient evidence to support one technique over another. Our study evaluated the biomechanical properties of four graft preparation techniques.

Extensor tendons were harvested from fresh frozen porcine trotters obtained from a local butcher shop and prepared in one of three configurations (n=5 per group): tendon only; tendon prepared with non-locking, running suture (2-0 FiberLoop, Arthrex, Naples, FL) spaced at 6 mm intervals; and tendon prepared with suture spaced at 12 mm intervals. A fourth configuration of suture alone was also tested. Tendons were allocated in a manner to ensure comparable average diameters amongst groups. Biomechanical testing occurred using custom jigs simulating radial and ulnar tunnels attached to a Bose Electroforce 3510 mechanical testing machine (TA Instruments). After being woven through the jigs, all tendons were sutured end-to-end with 2-0 PROLENE suture (Ethicon). Tendons then underwent a staircase cyclic loading protocol (5-25 Newtons [N] at 1 hertz [Hz] for 1000 cycles, then 5-50 N at 1 Hz for 1000 cycles, then 5-75 N at 1 Hz for 1000 cycles) until graft failure; if samples did not fail during the protocol, they were then loaded to failure. Samples were visually inspected for mode of failure after the protocol. A one-way analysis of variance was used to compare average tendon diameter; post-hac Tuhey tests were used to compare elongation and elongation rate. Survival to cyclic loading was analyzed using Kaplan-Meier survival curves with log rank. Statistical significance was set at a = 0.05.

The average tendon diameter of each group was not statistically different [4.17 mm (tendon only), 4.33 mm (FiberLoop spaced 6 mm), and 4.30 mm (FiberLoop spaced 12 mm)]. The average survival of tendon augmented with FiberLoop was significantly higher than tendon only, and all groups had significantly improved survival compared to suture only. There was no difference in survival between FiberLoop spaced 6 mm and 12 mm. Elongation was significantly lower with suture compared to tendon augmented with FiberLoop spaced 6 mm. Elongation rate was significantly lower with suture compared to all groups. Modes of failure included rupture of the tendon, suture, or both at the simulated bone and suture and/or tendon interface, and elongation of the entire construct without rupture.

In this biomechanical study, augmentation of porcine tendons with FiberLoop suture spaced at either 6 or 12 mm for DRUJ reconstruction significantly increased survival to a staircase cyclic loading protocol, as suture material was significantly stiffer than any of the tendon graft configurations.

Advances in algorithms developed with sensor data from smart phones demonstrates the capacity to passively collect qualitative gait metrics. The purpose of this feasibility study was to assess the recovery of these metrics following joint reconstruction. A secondary data analysis of an ethics approved global, multicenter, prospective longitudinal study evaluating gait quality data before and after primary total knee arthroplasty (TKA, n=476), partial knee arthroplasty (PKA, n=139), and total hip arthroplasty (THA, n=395). A minimum 24 week follow-up was required (mean 45±12, range 24 - 78). Gait bouts and gait quality metrics (walking speed, step length, timing asymmetry, and double support percentage) were collected from a standardized smartphone operating system. Pre- and post-operative values were compared using paired-samples t-tests (p<0.05). A total of 595 females and 415 males with a mean age of 61.9±9.3 years and mean BMI of 30.2±6.1 kg/m. 2. were reviewed. Walking speeds were lowest at post-operative week two (all, p<.001). Speeds exceeded pre-operative means consistently by week 21 (p=0.015) for PKA, and week 13 (p=0.007) for THA. The average weekly step length was lowest in post-operative week two (all, p<0.001). PKA and THA cases achieved pre-operative step lengths by week seven (p=0.064) and week 9 (p=0.081), respectively. The average weekly gait asymmetry peaked at week two post-operatively (all, p <0.001). Return to pre-operative baseline asymmetry was achieved by week 11 (p=0.371) for TKA, week six (p=0.541) for PKA, and week eight (p=.886) for THA. Double limb support percentages peaked at week two (all, p<0.001) and returned to pre-operative levels by week 24 (p=0.089) for TKA, week 12 (p=0.156) for PKA, and week 10 (p=0.143) for THA. Monitoring gait quality in real-world settings following joint reconstruction using smartphones is feasible, and may provide the advantage of removing the Hawthorne effect related to typical gait assessments and in-clinic observations

Introduction. Joint reconstruction remains a successful and popular surgery with advances in approaches, implants and techniques continually forthcoming. Various methods of skin closure exist to address issues in efficiency, aesthetics, and barrier to infection. While subcuticular skin closure techniques offer an aesthetic advantage to conventional skin stapling, no measurable differences have been reported. Furthermore, newer barbed sutures, such as the V-loc absorbable suture, theoretically distribute tension evenly through the wound and help decrease knot-related complications. To our knowledge, no literature exists on the rate of wound complications in joint arthroplasty with the use of V-loc suture for skin closure. We hypothesize that despite theoretical gains, skin closure with a V-loc (Covidien, Mansfield, MA) absorbable suture should be performed with caution. Methods & Materials. A retrospective chart review was conducted of 278 consecutive primary joint reconstruction cases performed by a single surgeon in 12 months from July 2009 through June 2010. Pre-operative history & physical reports were evaluated for co-morbidities (i.e diabetes mellitus), smoking status and body mass index (BMI). Operative dictations by the attending surgeon provided information on the surgical procedure, use of drain, wound closure technique and type of suture/staple used for skin closure. Skin was closed by the primary surgeon and his chief resident. Wounds were closed via staple gun or subcuticular stitch (3-0 Biosyn vs V-Loc) in a consecutive manner, depending on the surgeon's preference in that period. Post-operative clinic notes were reviewed to determine the occurrence of wound complications, issuance of antibiotic prescriptions, or return to the operating room. The cohort consisted of 106 males and 161 females at an average age of 63 years (range: 18–92). Overall, there were 153 procedures at the knee (including TKA, uni-compartmental arthroplasty, patello-femoral arthroplasty) and 125 procedures at the hip (including THA and hemi-arthroplasty). Results. In review of 278 consecutive primary joint reconstruction cases, there were 17 (6.1%) post-operative wound complications noted, including cellulitis, stitch abscesses, wound dehiscence, and deeper infections requiring OR irrigation and debridement. In 181 cases, staples were used for skin closure; in these cases, seven wound complications were noted (7/181, 3.9%). In 49 cases closed via a subcuticular Biosyn suture there were 4 wound complications noted (4/49, 8.1%). Six wound complications occurred in cases closed with a V-loc suture (6/45, 13.3%). Discussion. Aesthetics and efficiency often are the driving forces of innovation. We present the rate of wound complications in various superficial wound closure methods, including the V-loc, an innovative absorbable barbed suture. Based on our clinical experience, we promote consideration of wound and infectious complications when choosing a method of skin closure in joint reconstruction procedures

Challenging cases in shoulder surgery emphasizing joint reconstruction will be presented to a distinguished panel of experts. Audience participation will be encouraged. Preoperative assessment, imaging, operative techniques, and postoperative care will be emphasised. Special focus will be on shoulder replacement, especially reverse shoulder arthroplasty

INTRODUCTION. Multiple sources have consistently reported oxidation indices less than 0.1 with Marathon® inserts implanted up to 10 years. Understanding effects of oxidation level on UHMWPE wear in vivo is of great value. The objective of this study is to characterize the wear performance of Marathon® acetabular inserts at various levels of artificially induced oxidation, quantified using Bulk Oxidation Index (BOI) as determined per ASTM F2102, and to ascertain if wear rate is affected by progressive polyethylene oxidation. METHODS. GUR 1050 UHMWPE acetabular inserts, re-melted and cross-linked at 5.0Mrad (Marathon®, DePuy Synthes Joint Reconstruction, Warsaw, IN), were artificially aged per ASTM F-2003 in a stainless steel chamber at 5 atm. oxygen pressure and 70°C. Samples were maintained at temperature for 9, 10.4 and 11 weeks. After aging was completed, Fourier Transform Infra-Red (FTIR) spectroscopy was employed on one insert from each time point to evaluate the induced oxidation as a result of artificial aging. Resulting induced BOI values measured by FTIR were 0.195, 0.528 and 1.184. UHMWPE inserts had an inner diameter of 28mm and an outer diameter of 48mm and were articulated against 28mm diameter M-Spec® metal femoral heads (DePuy Synthes Joint Reconstruction, Warsaw, IN). Testing was conducted on a 12-station AMTI ADL hip simulator (AMTI, Watertown, MA) with load soak controls per ISO 14242-1:2014(E) in bovine serum (18mg/mL total protein concentration) supplemented with 0.056% sodium azide (preservative) and 5.56mM EDTA (calcium stabilizer). The UHMWPE inserts were removed from the machine, cleaned, and gravimetric wear determined per ISO 14242-2:2000(E) every 0.5 million cycles (MCyc) for 4.0 MCyc total. A two-tailed student's t-test was used (variance determined by F-test results) to analyze differences in wear rates between the three test groups. RESULTS. After 4.0 MCyc of wear testing, the average wear rate of the Marathon® UHMWPE acetabular inserts with OI levels of 0.195, 0.528 and 1.184 articulated against the CoCrMo femoral heads were 6.0 ± 4.2 mg/MCyc (±95% confidence interval), 8.7 ± 0.4 mg/MCyc and 15.3 ± 2.2 mg/MCyc, respectively (Figure 1). As BOI level increased, the wear rate also increased. Wear rates of inserts with BOI of 0.195 compared to 0.528 were not significantly different (p=0.11). Wear rates of inserts with BOI of 0.195 were significantly lower (p=0.00) compared to 1.184. Wear rates of inserts with BOI levels of 0.528 were significantly lower (p=0.00) compared to 1.184. DISCUSSION. This study aimed to characterize the wear performance of Marathon® acetabular inserts at three levels of oxidation created by accelerated aging. Artificially aged inserts with a BOI level similar to those reported from clinically retrieved Marathon® inserts (0.195) had a wear rate equivalent to non-aged inserts previously tested (data not shown), indicating the in vivo oxidation of this highly cross-linked UHMWPE has no effect on wear rate. Although not measured clinically, higher levels of oxidation may result in significantly higher wear rates in vivo

Surgical navigation in joint replacement has been developed for more than 10 years. After the initial enthusiastic period, it appears that few surgeons have included this technology into their routine practice. The reasons for this backflow are lack of evidence of any clinical superiority for navigation implanted prostheses, higher costs and longer operative time. However, navigation systems have evolved, and might still belong to the future of joint replacement. Although most studies did not observe clinically relevant differences between navigated and conventional joint replacement, some registry studies identified significant advantages in favor of navigation: less blood loss, less early revision, subtle but relevant functional improvement… If TKR may be more forgiving, there is a trend to use less invasive implants (UKR), which are technically more demanding and may benefit from navigation. Ligamentous balancing may be more accurate and more reproducible with the help of navigation, and in that way patient specific templates may benefit from navigation. New techniques (short stem hip implants, hip resurfacing) have a relevant learning curve which may be fastened with navigation support. Another key point may be the individual joint reconstruction: anatomy is different from one patient to the other, and navigation may help detecting these subtle differences to adapt a more physiological joint reconstruction, instead reconstructing all joints on the same model. New navigation systems now available are designed in a more user-friendly style, with more straightforward workflow, and may be adapted to every surgeon's need. Finally, navigation system may act as documentation and quality control system for health care providers, as well as a very powerful research tool for scientists and manufacturers

Tunning fork lines (TFL) were drawn on ankle anterior-posterior radiographs to assess the talar shift in ankle fractures. A 3-D ankle joint reconstruction was prepared by mapping normal ankle joint using auto CAD in 1997. TFL were drawn using normal anatomical landmarks on saggital, coronal and transverse planes. The ankle joint anatomical relationship with talus was studied in various rotation simulating radiographic anterior-posterior views and talar shift was studied. Between 2006 and 2012 on antero-posterior view of ankle radiographs and PACS, TFL were drawn. The premise is that in a normal radiograph the superior-lateral dome of the talus lies medial to the handle of TFL, and in ankle with talar shift the dome of the talus would cross this line laterally. In two district hospitals 100 radiographs were observed by 4 observers in 67 males and 33 females with mean age of 49 (15–82) years. The TFL confirmed talar shift with sensitivity of 99.2 % showing talarshift and inferior tibio-fibular ankle diastasis. We conclude that in ankle anterio-posterior view it is possible to comment on the talar shift and diastasis of the ankle joint, even if proper ankle mortise views were not available

Introduction. Tibiofemoral constraint in patients with total knee replacements (TKR) is dependent on both implant geometry and the surrounding soft tissue structures. Choosing more highly constrained geometries can reduce the contribution of soft tissue necessary to maintain joint stability [1]. Often when knee revision surgeries are required, the soft tissue and bone are compromised leading to the use of more constrained implants to ensure knee stability [2]. The current study quantifies the differences in varus-valgus (VV) and internal-external (IE) constraint between two types of total knee revision systems: SIGMA® TC3© and ATTUNE® REVISION. Methods. Nine cadaveric knees (7 male, age 64.0 ± 9.8 years, BMI 26.28 ± 4.92) were implanted with both fixed-bearing SIGMA TC3 and ATTUNE REVISION knee systems. Five knees received the TC3 implant first, while the remaining 4 received the ATTUNE implant first. The knees were mounted in an inverted position, and a six degree-of-freedom force-torque sensor (JR3, Woodland, CA) was rigidly secured to the distal tibia (Fig. 1). A series of manual manipulations applying IE and VV torques was performed through the flexion range [3]. Each specimen was then revised to the alternate revision system, and the manual manipulations were repeated. Joint loads were calculated, and tibiofemoral kinematics were described according to the Grood-Suntay definition [4]. VV and IE kinematics were calculated as a function of flexion angle, VV torque, and IE torque as has been described previously [3]. The knees were analysed at ±6 Nm VV and ±4 Nm IE, and the kinematics were normalized to the zero load path. A paired t-test (p < .05) was employed to identify significant differences between the kinematics of the two knee systems at 10º flexion increments. Results. Less VV motion was observed in the ATTUNE REVISION system compared to the TC3 system reaching statistical significance in mid-flexion. (Fig. 2). No significant differences were observed in IE rotation between the two designs, except in full extension where the SIGMA TC3 provided increased constraint (Fig. 3). Discussion. The ATTUNE REVISION System provided increased VV constraint compared to the TC3 design. The ATTUNE tibial post was more conforming to the femoral box throughout flexion, which contributed to the increased constraint. However, this increase was not concurrent with a reduction in IE rotational freedom as has been common with more constrained revision systems [5]. ATTUNE REVISION provides additional VV stability while retaining knee IE freedom and, therefore, may enable more natural knee kinematics for patients with MCL deficiency in need of a revision TKR. Future work will focus on how the increased levels of VV constraint affect weight-bearing knee kinematics in the presence of ligament deficiency. Acknowledgements. This work was supported by DePuy Synthes Joint Reconstruction, Warsaw, Indiana, a Johnson and Johnson Company. For figures and references – please contact authors directly

Introduction and Aims. Clinically many factors such as variations in surgical positioning, and patients' anatomy and biomechanics can affect the occurrence and severity of edge loading which may have detrimental effect on the wear and durability of the implant. Assessing wear of hundreds of combinations of conditions would be impractical, so a preclinical testing approach was followed where the occurrence and severity of edge loading can be determined using short biomechanical tests. Then, selected conditions can be chosen under which the wear can be determined. If a wear correlation with the magnitude of dynamic separation or the severity of edge loading can be shown, then an informed decision can be made based upon the biomechanical results to only select important variables under which the tribological performance of the implant can be assessed. The aim of this study was to determine the relationship between the wear of ceramic-on-ceramic bearings and the (1) magnitude of dynamic separation, (2) the maximum force reached during edge loading and (3) the severity of edge loading resulting from component translational mismatch between the head and cup centres. Methods. The Leeds II hip joint simulator with a standard walking cycle and 36mm diameter ceramic-on-ceramic bearings (BIOLOX. ®. delta, DePuy Synthes Joint Reconstruction, Leeds, UK.) were used. The study was in two parts. Part one: a biomechanical study where the dynamic separation, the maximum load during edge loading, and the duration of edge loading alongside the magnitude of forces under edge loading (severity of edge loading) were assessed. Part two; a wear study where the wear rates of the bearing surfaces were assessed under a series of input conditions. These input testing conditions included inclining the acetabular cups at 45° and 65° cup inclination angle (in-vivo equivalent), with 2, 3, and 4mm medial-lateral component mismatch between the centres of the head and the cup. This equated to six conditions being assessed, each with three repeats for the biomechanical test, and six repeats completed for the wear study. The severity of edge loading was assessed as described in Equation 1. Severity of Edge Loading = ∫. t. t0. F(x) dx + ∫. t. t0. F(y) dy … Equation 1,. where F(x) is the axial load, F(y) is the medial-lateral load and t-t0 is the duration of edge loading. The wear of the ceramic bearings were determined using gravimetric analysis (XP205, Mettler Toledo, UK). Results. The wear rates of ceramic-on-ceramic bearings increased as the magnitude of dynamic separation (Figure 1), the maximum load at the rim during edge loading (Figure 2), and the severity of edge loading (Figure 3) increased. The magnitude of dynamic separation was found to have the highest correlation to the wear rate under the conditions tested in this study (R. 2. =0.94). Conclusions. A preclinical testing approach has been developed to understand the occurrence and severity of edge loading associated with variation of component positioning. A good correlation was found between the wear rates obtained for ceramic-on-ceramic bearings and the magnitude of parameters obtained under edge loading during a short-term biomechanical study. For figures/tables, please contact authors directly.

To evaluate a innovate one stage procedure of the PJI knee treatment using computed assisted guidance. Our objectives; to increase the functional results by optimizing the anatomical joint reconstruction and to verifie if CAS help to simplifie and standardize these complex surgeries. It's a prospective, single surgeon study. Since septembre 2011, 41 patients treated for chronic knee PJI in a one stage revision (one of them had a ipsilateral chronic knee arthritis). For all of them, a computed assisted guidance, the ExactechGPS® system was used. This system offers the possibility to define specific profiles to performe primary TKA surgeries. A personnalized profile of revision was created. All surgeries were performed with the same protocole; independently of the type of germ, with no use of tourniquet, no drainage by performing the same debridement procedure step by step and by using the same knee components. 27 males, 14 female with 26 PJI of primary TKA, one infected unicompartimental prosthesis and 15 PJI of first revised TKA has been treated. The average age was 71 years old (55–87). The time of surgery was on average 135 mn (120 – 195 mn). The average time of hospitalization was 10 days (7–16). The average follow up was 20,9 months (6–47 months). The ROM were on average 114,7% (90°–130°), None post operative HKA outliers were reported. 3 patients presented a failure of the PJI treatment (one after a local open traumatism, one diabetic patient, one after a early revision for mechanical complication). None specific CAS complications and no failure of the CAS procedures are reported. As surgeon, CAS simplified the management of the bone loss after debridement and the control of the differents parameters (HKA, external femoral rotation, ligamentary balancing, lign joint…) by a real time feedback. we changed our practise by using more constraint condylar component instead hinge prostheses. With a rate of success of 92,7% at this follow up, the one stage option appears to be valided. Using CAS is a safe option with no specific complication. It increases the quality of the ROM, a earlier functional recovery and a better middle term clinical result. Both combined, It should be a optimal medicoeconomical solution. compared revision using mechanical ancillary

Introduction. Moderately crosslinked, thermally treated ultrahigh molecular weight polyethylene (UHMWPE) has to date demonstrated a good balance of wear resistance and mechanical properties. MARATHON™ Polyethylene (DePuySynthes Joint Reconstruction, Warsaw, IN) is made from polyethylene resin GUR 1050, gamma-irradiated at a dose of 5.0 Mrads to create crosslinking of polyethylene, and followed by a remelting process to eliminate free radicals for oxidative stability. 10-year clinical study [1] and laboratory wear simulation tests [2–3] have reported excellent wear performance of the MARATHON poly. There continues to be demand for improved head-to-shell ratio acetabular systems because larger head sizes have the benefits of increased stability and range of motion. The increased head-to-shell ratio is often times achieved by using a reduced liner thickness. One of the clinical concerns of thinner poly liners is the potential for rim fracture, particularly in the occurrences of rim loading or impingement at high cup angles [4–7]. This study investigated the performance of thinner poly liners to the challenge of high angle rim loading and neck-to-liner impingement. Materials and Methods. Three groups of ETO sterilized MARATHON polyethylene liners (ID/OD: 28/44, 32/48, and 36/52 mm) were paired with matching CoCrMo heads (n=6 each group). To simulate rim loading, liners were assembled in the metal shells tilted at 64° (Figure 1) with sinusoidal loading (0 to 5000N at 3Hz) in a 37°C water bath for 5-million cycles or until component failure, whichever occurred first. For neck-liner impingement testing, metal shells were potted at 54º (in the abduction/adduction plane with a ±10° of motion per ISO 14242–1 [8]) on a hip simulator (n=4 each group) using a physiological loading (max 3000N at 1Hz) for 3-million cycles (Figure 2). The impingement occurred at 64º during the simulated gait cycle (Figure 3). The liners were inspected every million cycles, using a high intensity light to search for signs of crack initiation and/or fractures. Both test methods were validated to be able to replicate liner fractures. Results. All MARATHON ETO liners passed 5-million cycles of high angle fatigue testing. All liners passed 3-million cycles of impingement testing. Discussion. Causes of liner fractures can be multi-factorial. Examples of influencing factors are: poly material, component designs, patient activity level, implant orientations, and neck-liner impingement. Improved head-to-shell ratio design requires reduction of the liner thickness, which raises the concern of liner fracture. In this study, we investigated adverse testing conditions of rim-loading and neck-liner impingement, in order to evaluate the mechanical performance of thin polyethylene liner

Objectives. An optimal reconstruction of the joint anatomy and physiology during revision total knee replacement (RTKR) is technically demanding. The standard navigation systems were developed for primary procedures, and their adaptation to RTKR is difficult. We present a new navigation software dedicated to RTKR. The rationale of this new software was to allow a virtual planning of the joint reconstruction just after removal of the primary prosthesis. Methods. The new software was developed on the basis of a non-image based navigation system which has been extensively validated for implantation of a primary TKR. Following changes have been implemented: 1) to define and control the vertical level of the joint space on both tibia and femoral side; 2) to measure the tibio-femoral gaps independently in flexion et en extension on both medial and lateral tibio-femoral joints; 3) to virtually plan and control the vertical level and the orientation of the tibia component; 4) to virtually plan and control the sizing and the 3D positioning of the femoral component (figure 1); 5) to virtually plan and control the potential bone resection; 6) to virtually plan and control the potential bone defects and their reconstruction (bone graft or augments) (figure 2); 7) to virtually plan and control the size, the length and the orientation of the stems extensions independently on the femoral and on the tibia side (figure 3). The validity of the concept has been tested by 20 patients operated on for RTKR for any reason, with a routine reconstruction with a cemented, unconstrained revision implant. The accuracy of the experimental software was assessed 1) during the procedure after implantation of the RTKR by measuring the medial and lateral laxity in full extension and 90° of knee flexion with the navigation system, and 2) on post-operative radiographs. Results. No system failure was observed. The virtual planning of the reconstruction was possible in all cases. The intra-operative control of the different reconstruction steps was possible in all cases. The mean coronal tibio-femoral angle was 0+3°, and no outlier was observed. Coronal and sagittal orientation of the prosthetic components was considered satisfactory in all directions for 16 cases. The desired vertical level of the joint space was achieved in all cases. The desired patella height was achieved in 15 cases. The measurement of the knee laxity was satisfactory in 16 cases. A good bone-prosthesis contact was achieved in 17 cases for the tibia, but it was not possible to analyze accurately this criterion for the femur. Conclusion. The software used in the current study allowed performing a straightforward reconstruction of the knee joint anatomy and physiology during RTKR. The virtual planning prevented to perform repetitive trials with different technical solutions which are often necessary during conventional RTKR. The operating time may be consequently decreased

Introduction. Edge loading of hip replacements may result in plastic deformation, creep and wear at the rim of the cup and potentially fatigue failure. Variations in component positioning can lead to dynamic separation and edge loading [1]. The aim of this study was firstly to investigate the effects of translational and rotational positioning on the dynamic separation and severity of edge loading, and secondly to determine the wear rates of metal-on-polyethylene bearings under the more severe separation and edge loading conditions. Materials and Methods. A hip joint simulator (ProSim EM13, Simulation Solutions, UK) was set up with 36mm diameter metal-on-polyethylene hip replacements (Marathon™, DePuy Synthes Joint Reconstruction, Leeds, UK). This study was in two parts. I) A biomechanical test was carried out at 45° (n=3) and 65° (n=3) cup inclination angles with 1, 2, 3 and 4 (mm) medial-lateral translational mismatch between the head and cup centres. The severity of edge loading was calculated from the area under the axial force and medial-lateral force outputs during the time of separation when the load was acting on the edge of the cup [2]. II) For two conditions (two million cycles), the head and cup were concentric for cups inclined equivalent clinically to 45° (n=3) and 65° (n=3). For two further conditions (three million cycles), 4mm medial-lateral translational mismatch between centres was applied for cups inclined equivalent clinically to 45° (n=6) and 65° (n=6). Volumetric wear measurements were undertaken at one million cycle intervals. The lubricant was diluted new-born calf serum (25% v/v). Plastic deformation and wear were determined using a coordinate measurement machine. Mean values were calculated with 95% confidence limits. Statistical analysis was carried out using ANOVA and a t-test with significance levels taken at p<0.05. Results. The largest dynamic separation measured was at a 65° cup inclination angle with 4mm translational mismatch (Figure 1). At 1mm and 2mm of translational mismatch there was insignificant or no edge loading due to dynamic separation. The most severe edge loading conditions occurred at 4mm of translational mismatch at 45° and 65° inclination angles (p<0.01, Figure 2). The wear rates under standard concentric conditions were 12.9±3.8 and 15.4±5.0 mm. 3. /million cycles for cups inclined at 45° and 65° respectively. Higher wear rates were observed under 4mm of translational mismatch at 45° (21.5±5.5mm. 3. /million cycles, p<0.01) and 65° (23.0±5.7mm. 3. /million cycles, p<0.01) cup inclination angles. The mean maximum penetration depth at the edge of the cup at three million cycles was 0.10±0.05mm and 0.28±0.04mm at 45° and 65° cup inclination angles respectively (p<0.01), indicating substantial plastic deformation due to edge loading (Figure 3). Conclusion. Surgical positioning is important for long term clinical success of hip joint implants. A method has been developed to study the effects of rotational and translational positioning of metal-on-polyethylene bearings. Severe edge loading increased the wear and deformation of polyethylene liners at the rim. Minimising the occurrence and severity of edge loading and reducing the dynamic separation in vivo may reduce revision rates associated with polyethylene bearings

Tunning fork lines (TFL) were drawn on ankle anterior-posterior radiograph to assess the talar shift. A 3-D ankle joint reconstruction was prepared by mapping normal ankle joint using auto CAD in 1997. Tunning fork lines were drawn using normal anatomical landmarks on saggital, coronal and transverse planes. The ankle joint anatomical relationship with talus was studied in various rotation simulating radiographic anterior-posterior views and talar shift was studied. Between 2006 and 2012 on antero-posterior view of ankle radiographs and PACS, ‘Tunning Fork Lines’ (TFL) were drawn. The superior two vertical lines of the TFL were drawn above the ankle joint perpendicular to the distal tibial articular surface. First line tangent to anterior lip of the inferior tibio-fibular joint and second line tangent to the posterior lip of the inferior tibio-fibular joint parallel to each other. The horizontal third line was drawn parallel to distal tibial articular surface perpendicular to first two lines connecting them. The fourth line (handle of the tunning fork) was drawn vertically below the ankle joint midway between the first two lines perpendicular to the third line. In a normal radiograph the superior-lateral dome of the talus lies medial to the handle of TFL, and in ankle with talar shift the dome of the talus crosses this line laterally. In two district hospitals 100 radiographs were observed by 4 observers in 67 males and 33 females with mean age of 49 (15–82) years. The TFL confirmed talar shift with sensitivity of 99.2 % showing talarshift and inferior tibio-fibular ankle diastasis. We conclude that in ankle anterio-posterior view it is possible to comment on the talar shift and diastasis of the ankle joint if proper ankle mortise view is not available

Introduction Modern metal-on-metal hip resurfacing (RHA) was introduced as a bone-preserving method of joint reconstruction for young and active patients; however, the large diameter of the bearing surfaces is of concern for potentially increased metal ion release. Patients and methods 71 patients (< 65 yrs) were randomly assigned to receive either a RHA (n=38) or a conventional metal-on-metal (MoM) THA (n=33). Functional outcomes were assessed preoperatively, at 6, 12 and 24 months. Cobalt and chromium blood levels were analyzed preoperatively, at 3, 6, 12 and 24 months. Results All functional outcome scores improved highly significant for both groups. At 12 and 24 months the UCLA Activity score was significantly higher for the RHA patients, the OHS only at 24 months. However, in spite of randomization UCLA scores also appeared to be higher in RHA patients at baseline. RHA patients were more satisfied at 12 months. Cobalt concentrations were significantly higher for RHA only at 3 and 6 months. Chromium levels remained significantly higher for RHA until 24 months. No pseudotumors were encountered in either group so far. One RHA was revised for early aseptic loosening and in two THA's a cup insert was exchanged for recurrent dislocation. Conclusion RHA patients scored significantly higher on UCLA, OHS and satisfaction at some intervals, however, as for the UCLA preoperative levels were already in favor of RHA. Chromium blood levels were significantly higher for RHA, whereas for cobalt this was only observed up to 6 months. The true value of RHA against THA will be determined by longer follow-up and a possible shift of balance between their respective (dis)advantages

ORIF is the treatment of choice for the majority of acetabular fractures with the ultimate goal of native hip preservation. As long as anatomic reduction and joint congruency is achieved, the results of ORIF have led to good to excellent outcomes. Total hip arthroplasty (THA) after acetabular fracture is indicated: 1.) acutely in the setting of a fracture where ORIF has been shown to portray a poor prognosis (severe femoral head and/or posterior wall impaction, dome comminution (gull sign) or 2.) in the presence of the sequelae of acetabular fractures such as posttraumatic arthritis or osteonecrosis. Independent of the setting, THA after acetabular fracture presents unique challenges to the orthopaedic surgeon and in many instances requires a team approach that includes both joint reconstruction and trauma specialists. The main goal of the operation is to restore continuity of the fractured columns prior to implantation of an uncemented acetabular component. Technical challenges include infection, residual pelvic deformity, acetabular bone loss and/ or ununited fractures, osteonecrosis of bone fragments, retained hardware, heterotopic ossification, sciatic nerve compromise, and the difficulties in obtaining long-term socket fixation. Careful pre-operative assessment with review of x-rays and CT scans to assess bone loss, fracture nonunion, and infection is necessary. The surgeon must anticipate more blood loss, longer operative times, and difficulties with exposure and must anticipate the need of special tools intra-operatively such as pelvic reconstruction plates, use of autogenous bone graft, metal cutting instruments and post-operative heterotopic ossification prophylaxis either in the form of NSAIDS or radiation. In case of a necrosis, nonunion, or bone loss principles of revision total hip arthroplasty are commonly used and today the use of highly porous metals is particularly useful. Cemented acetabular components should be avoided. Care should be taken with cup position as distorted anatomy may influence cup position and bony impingement may lead to dislocation. The results of THA in general has provided excellent pain relief and functional improvement but the biggest historical problem has been socket fixation and bearing surface wear, hopefully now improved with the advent of highly porous metals and alternative bearing surfaces

Aims

Patient-reported outcome measures have become an important part of routine care. The aim of this study was to determine if Patient-Reported Outcomes Measurement Information System (PROMIS) measures can be used to create patient subgroups for individuals seeking orthopaedic care.

Background. The Kotz Modular Femoral Tibial Replacement system has been one of the most widely utilised uncemented modular systems for bone and joint reconstruction after tumour resection. We have identified a significant incidence of mechanical failure and breakage of the prosthesis. The purpose of this investigation is to review the modes of implant failure and the outcomes after prosthetic revision for a broken Kotz prosthesis. Methods. Over 20 years there were 121 distal femoral, 55 proximal tibial, 47 proximal femoral and 12 total femoral replacements performed. Results. Out of 180 currently living patients there were 27 implant fractures in 23 patients (13%) with 22 distal femoral and five proximal tibial implant failures. Mechanical failures occurred at a mean of 77 months (range 24-170). There were 21 stem fractures. Five fractured at the derotation lug and one fractured the tibial housing. Lug fracture is an unreported mode of failure of these implants. The implant design selected for revision was very much dependent on when the fractured implant was revised. Eleven patients had new KMFTR stems inserted; 4 Restoration stems (one of which was cemented), 3 GMRS stems (one of which was cemented), two total femora and one Compress (Biomet) implants have been utilised, all with custom adaptors between the stem and the KMFTR system. There were 12 complications (44%), seven infections, three implant re-fractures, one vascular insufficiency necessitating amputation and one per-prosthetic fracture. The mean pre-implant fracture and post-revision TESS scores were 80.9 (Range 54.2-98.3) and 79.1 (50-96.7). The MSTS87 pre- and post- scores were 26.8 (14-33) and 26.1 (15-33) respectively. The MSTS93 also demonstrated no differences in the pre-fracture and post-revision scores with 75.4 (50-93) and 74.8 (40-100). Conclusion. Our data illustrate that these prostheses can often be successfully revised by trephining out the broken stem and inserting new uncemented stems. Functional outcome continues to be good and is comparable to pre-revision levels, despite a 44% complication rate