Joint Reconstruction

A dynamic programming algorithm is developed for maximum-likelihood reconstruction of the set of all ancestral amino acid sequences in a phylogenetic tree. To date, exhaustive algorithms that find the most likely set of ancestral states (joint reconstruction) have running times that scale exponentially with the number of sequences and are thus limited to very few taxa. The time requirement of our new algorithm scales linearly with the number of sequences and is therefore applicable to practically any number of taxa. A detailed description of the new algorithm and an example of its application to cytochrome b sequences are provided.

Background Biomechanical studies comparing various surgical techniques for acromioclavicular joint reconstruction have reported that semitendinosus tendon graft for coracoclavicular ligament reconstruction provides a substantial improvement in initial stability and a load-to-failure equivalent to the intact coracoclavicular ligaments. Although it represents a biomechanical improvement compared with coracoacromial ligament transfer, there is still a lack of prospective comparative studies confirming the clinical relevance of these biomechanical findings. Hypothesis Semitendinosus tendon graft for coracoclavicular ligament reconstruction is associated with superior clinical results compared with a modified Weaver-Dunn procedure in chronic complete acromioclavicular joint dislocation. Study Design Cohort study; Level of evidence, 2. Methods Twenty-four patients (mean age, 42 years) with painful, chronic Rockwood type III through V acromioclavicular joint dislocations were subjected to surgical reconstruction. In 12 patients, a modified Weaver-Dunn procedure was performed; in the other 12 patients, autogenous semitendinosus tendon graft was used. Clinical evaluation was performed using the American Shoulder and Elbow Surgeons shoulder score and the Constant score after a mean follow-up time of 37 months. Preoperative and postoperative radiographs were compared. Results The mean American Shoulder and Elbow Surgeons shoulder score improved from 74 ± 7 points preoperatively to 86 ± 8 points postoperatively in the Weaver-Dunn group, and from 74 ± 4 points to 96 ± 5 points in the semitendinosus tendon group (P < .001 for both techniques). The mean Constant score improved from 70 ± 8 points to 81 ± 8 points in the Weaver-Dunn group, and from 71 ± 5 points to 93 ± 7 points in the semitendinosus tendon group (P < .001). The results in the semitendinosus tendon group were significantly better than in the Weaver-Dunn group (P < .001). The radiologic measurements showed a mean coracoclavicular distance of 12.3 ± 4 mm in the Weaver-Dunn group increasing to 14.9 ± 6 mm under stress loading, compared with 11.4 ± 3 mm increasing to 11.8 ± 3 mm under stress in the semitendinosus tendon group. The difference during stress loading was statistically significant (P = .027). In the semitendinosus tendon group, horizontal displacement of the lateral clavicle end could be reduced in all cases with type IV dislocation. Conclusion Semitendinosus tendon graft for coracoclavicular ligament reconstruction resulted in significantly superior clinical and radiologic outcomes compared to the modified Weaver-Dunn procedure.

Estimating hand-object manipulations is essential for in- terpreting and imitating human actions. Previous work has made significant progress towards reconstruction of hand poses and object shapes in isolation. Yet, reconstructing hands and objects during manipulation is a more challeng- ing task due to significant occlusions of both the hand and object. While presenting challenges, manipulations may also simplify the problem since the physics of contact re- stricts the space of valid hand-object configurations. For example, during manipulation, the hand and object should be in contact but not interpenetrate. In this work, we regu- larize the joint reconstruction of hands and objects with ma- nipulation constraints. We present an end-to-end learnable model that exploits a novel contact loss that favors phys- ically plausible hand-object constellations. Our approach improves grasp quality metrics over baselines, using RGB images as input. To train and evaluate the model, we also propose a new large-scale synthetic dataset, ObMan, with hand-object manipulations. We demonstrate the transfer- ability of ObMan-trained models to real data.

PURPOSE The purpose of this study was the assessment of the long-term safety and effectiveness of the Techmedica (Camarillo, CA) CAD/CAM Total Temporomandibular Joint Reconstruction System (now called the TMJ Concepts Patient Fitted Total Temporomandibular Joint Reconstruction System, Ventura, CA). PATIENTS AND METHODS A survey was mailed to the available addresses of 170 (79%) of the 215 patients who had been implanted with the Techmedica System devices between 1990 and 1994. Seventy-nine (46%) surveys were returned by the US Postal Service as undeliverable. Three patients (1.4%) were reported as deceased in returns from relatives. Therefore, of the remaining 91 possible responses, 60 (65.9%) were returned. Fifty-eight (58) surveys, considered complete and valid (96.7%), representing 97 (39 bilateral, 19 unilateral) devices with a mean follow-up of 107.4 +/- 15.5 months (range, 60 to 120 months) were analyzed. Subjective data related to pain, mandibular function, diet consistency, and present quality of life were collected using visual analog scales. Objective measures of mandibular interincisal opening and lateral excursions were obtained from direct measurements using the Therabite (Therabite, Philadelphia, PA) measuring scale provided in the survey with instructions as to its use. RESULTS Analysis of the subjective data at 10 years revealed a 76% reduction in mean pain scores and a 68% increase in mean mandibular function and diet consistency scores (P <.0001). Analysis of objective data revealed a 30% improvement in mandibular range of motion after 10 years (P =.0009). Long-term quality of life improvement scores were statistically related to the number of prior temporomandibular joint operations the patients had undergone. CONCLUSION These data indicate that the CAD/CAM Patient Fitted Total Temporomandibular Joint Reconstruction System has proved to be a safe and effective long-term management modality in the patient population surveyed for this study.

Recent advances in technology have enabled the combination of positron emission tomography (PET) with magnetic resonance imaging (MRI). These PET-MRI scanners simultaneously acquire functional PET and anatomical or functional MRI data. As function and anatomy are not independent of one another the images to be reconstructed are likely to have shared structures. We aim to exploit this inherent structural similarity by reconstructing from both modalities in a joint reconstruction framework. The structural similarity between two modalities can be modelled in two different ways: edges are more likely to be at similar positions and/or to have similar orientations. We analyse the diffusion process generated by minimizing priors that encapsulate these different models. It turns out that the class of parallel level set priors always corresponds to anisotropic diffusion which is sometimes forward and sometimes backward diffusion. We perform numerical experiments where we jointly reconstruct from blurred Radon data with Poisson noise (PET) and under-sampled Fourier data with Gaussian noise (MRI). Our results show that both modalities benefit from each other in areas of shared edge information. The joint reconstructions have less artefacts and sharper edges compared to separate reconstructions and the l2-error can be reduced in all of the considered cases of under-sampling.

We present a novel intrinsic method for joint reconstruction of both image and motion in positron emission tomography (PET). Intrinsic motion compensation methods exclusively work on the measured data, without any external motion measurements. Most of these methods separate image from motion estimation: They use deformable image registration/optical flow techniques in order to estimate the motion from individually reconstructed gates. Then, the image is estimated based on this motion information. With these methods, a main problem lies in the motion estimation step, which is based on the noisy gated frames. The more noise is present, the more inaccurate the image registration becomes. As we show both visually and quantitatively, joint reconstruction using a simple deformation field motion model can compete with state-of-the-art image registration methods which use robust multilevel B-spline motion models.

Quantitative diffusion imaging is a powerful technique for the characterization of complex tissue microarchitecture. However, long acquisition times and limited signal‐to‐noise ratio represent significant hurdles for many in vivo applications. This article presents a new approach to reduce noise while largely maintaining resolution in diffusion weighted images, using a statistical reconstruction method that takes advantage of the high level of structural correlation observed in typical datasets. Compared to existing denoising methods, the proposed method performs reconstruction directly from the measured complex k‐space data, allowing for Gaussian noise modeling and theoretical characterizations of the resolution and signal‐to‐noise ratio of the reconstructed images. In addition, the proposed method is compatible with many different models of the diffusion signal (e.g., diffusion tensor modeling and q‐space modeling). The joint reconstruction method can provide significant improvements in signal‐to‐noise ratio relative to conventional reconstruction techniques, with a relatively minor corresponding loss in image resolution. Results are shown in the context of diffusion spectrum imaging tractography and diffusion tensor imaging, illustrating the potential of this signal‐to‐noise ratio‐enhancing joint reconstruction approach for a range of different diffusion imaging experiments. Magn Reson Med, 2013. © 2012 Wiley Periodicals, Inc.

AIM To establish minimum clinically important difference (MCID) for measurements in an orthopaedic patient population with joint disorders. METHODS Adult patients aged 18 years and older seeking care for joint conditions at an orthopaedic clinic took the Patient-Reported Outcomes Measurement Information System Physical Function (PROMIS® PF) computerized adaptive test (CAT), hip disability and osteoarthritis outcome score for joint reconstruction (HOOS JR), and the knee injury and osteoarthritis outcome score for joint reconstruction (KOOS JR) from February 2014 to April 2017. MCIDs were calculated using anchor-based and distribution-based methods. Patient reports of meaningful change in function since their first clinic encounter were used as an anchor. RESULTS There were 2226 patients who participated with a mean age of 61.16 (SD = 12.84) years, 41.6% male, and 89.7% Caucasian. Mean change ranged from 7.29 to 8.41 for the PROMIS® PF CAT, from 14.81 to 19.68 for the HOOS JR, and from 14.51 to 18.85 for the KOOS JR. ROC cut-offs ranged from 1.97-8.18 for the PF CAT, 6.33-43.36 for the HOOS JR, and 2.21-8.16 for the KOOS JR. Distribution-based methods estimated MCID values ranging from 2.45 to 21.55 for the PROMIS® PF CAT; from 3.90 to 43.61 for the HOOS JR, and from 3.98 to 40.67 for the KOOS JR. The median MCID value in the range was similar to the mean change score for each measure and was 7.9 for the PF CAT, 18.0 for the HOOS JR, and 15.1 for the KOOS JR. CONCLUSION This is the first comprehensive study providing a wide range of MCIDs for the PROMIS® PF, HOOS JR, and KOOS JR in orthopaedic patients with joint ailments.

Background: Posttraumatic conditions of the proximal interphalangeal and metacarpophalangeal joints require arthroplasty or fusion for pain control and functional improvement. Arthroplasty is increasingly becoming a preferred option for maintaining joint motion. However, a formal systematic review comparing the three currently available techniques—vascularized toe joint transfer, silicone, and PyroCarbon arthroplasty—has not been performed to critically evaluate outcomes and complication rates for these three options. Methods: The authors used a formal systematic review of all available world literature (English and non-English). Data collection included active arc of motion as the primary outcome, and complication rates. Results: Five hundred twenty articles were identified, reviewed, and screened through multiple inclusion/exclusion criteria. The mean proximal interphalangeal active arcs of motion for vascularized toe joint, silicone, and PyroCarbon were 37 ± 9 degrees, 44 ± 11 degrees, and 43 ± 11 degrees, respectively. The mean metacarpophalangeal active arcs of motion for vascularized toe joint and silicone were 34 ± 10 degrees and 47 ± 16 degrees, respectively. Major complication rates requiring joint revision procedures for vascularized toe joint, silicone, and PyroCarbon were 29, 18, and 33 percent, respectively. Conclusions: Vascularized toe joint transfer has a worse active arc of motion and a higher complication rate when compared with silicone implant arthroplasty for both proximal interphalangeal and metacarpophalangeal joints. Early data suggest that PyroCarbon implants may be associated with higher rates of major complications. Given the lack of improvement in outcomes for posttraumatic finger joint reconstruction over the past 40 years, research efforts should focus on future development of novel arthroplasty devices.

BACKGROUND Dislocation of the sternoclavicular joint is a rare injury that has a low incidence of signifcant long-term symptoms. Surgical reconstruction of the joint is indicated in patients with symptomatic, chronic anterior instability or with irreducible or recurrent posterior instability. There have been many reported techniques for stabilization of the joint, but few investigators have reported more than several cases. The ideal reconstruction has not been identifed. PURPOSE The purpose of this investigation was to perform a systematic review of the available literature with the objective of identifying one technique of sternoclavicular reconstruction that could be recommended. METHODS A systematic review of literature pertaining to treatment of sternoclavicular joint injuries was performed, focusing on clinical reports with at least six patients and 1 year of follow-up. We also reviewed biomechanical reports pertaining to sternoclavicular reconstruction. RESULTS Six clinical reports and two biomechanical studies were identifed that met our inclusion criteria. Treatments described in the clinical reports included conservative treatment with a sling, repair of the joint capsule with provisional stabilization, and joint reconstruction with local tissue or graft tissue. One biomechanical study compared the strength of three reconstruction techniques. CONCLUSION Reconstruction with tendon tissue woven in a figure-of-eight pattern through drill holes in the manubrium and clavicle is stronger than reconstructions with local tissue. The review of clinical reports suggests excellent outcomes with this technique, and it is recommended in cases of chronic instability. In cases of acute instability requiring open reduction or inability to maintain a reduction in a posterior dislocation, there is evidence that repair of the joint capsule is suffcient surgical treatment.