According to the Agency for Healthcare Research and Quality, more than 285,000 total hip and 600,000 knee replacements are performed each year in the United States. In the 1980s, cementless implants were introduced. Direct bone ingrowth and ongrowth, namely osseointegration, to the implant led to a more durable implant-bone interface than possible with cement and avoided the complications caused by cement insertion and the troublesome removal of cement during revision surgery. Because cementless implants depend on new bone growth for stability, they require a longer healing time than cemented replacements. Many studies have been performed to optimize implant geometry, and surface topography, texture and coating to maximize new bone growth. However, the longevity of these implants is not always predictable. One cause of failure is the implant instability caused by suboptimal osseointegration. Our lab has developed a mouse model using a titanium porous implant inserted to proximal tibia to mimic the knee arthroplasty. With this model, we will investigate factors and cell-signaling pathways which affect and regulate osseointegration. We will also test the efficacy of various anabolic and anti-resorptive agents on osseointegration. Histomorphometry, back scattered electron microscopy, microCT, mechanical testing will be used to asses bone quantity and quality. Immunohistochemistry and rtPCR will be used to detect signaling pathways. The summer student will assist with mouse surgery, administration of agents to mice, tissue collection, and data analysis.
The use of the genetic screening is a new tool for the treatment of adolescent idiopathic scoliosis. This has so far been useful in predicting which patients with mild to moderate scoliosis will progress to require surgical treatment. The utility of genetics-based testing has not been used to predict post-operative progression. As such, we have been unable to find evidence of genetics-based testing to predict risk of post-operative progression. A genetics-based test should be constant over the course of a patient’s lifetime. Therefore, we will be able to study risk of post-operative progression more accurately and efficiently in a retrospective fashion, in particular by identifying those patients who progress to further deformity despite definitive treatment. Genetic testing has only been studied with respect to its relationship to overall magnitude of progression. There has been, to date, no discussion of its association with curve type or its relationship to further progression after fusion. For example, vertebra level selection in posterior spine fusion is a controversial topic, which will likely elicit differing opinions as long as the procedure is performed. Often the lumbar curve will not be touched during a spinal fusion, but the current algorithms used to fuse or not fuse (a so-called “selective thoracic fusion”) involve only classic clinical criteria. The student will perform genetic testing on pediatric patients who have already undergone spinal fusion as part of a historical database. The student will also enroll patients for further study in using the genetic test as part of future surgical decision-making. The student will have the opportunity to present his/her research to the pediatric orthopedic surgery department, as well as scrub in the operating room during spine surgery.
Studies in our laboratory have demonstrated mitochondrial dysfunction in tendonopathy. We are testing a novel small peptide drug that can restore mitochondrial oxidative function.
The purpose of this study is to use a mouse model of periprosthetic joint infection (PJI) to evaluate the in-vivo effect of pre-surgical systemic antibiotics on staphylococcus aureus PJI and determine if this effect improves the outcome of surgery. We hypothesize that systemic antibiotics will help limit the spatial spread of infection in PJI, permit more effective surgical resection, and minimize maladaptive host inflammatory responses. If successful, these study results could propel a paradigm shift in how PJI is treated. This study has 3 specific phases. Phase 1 has been successfully completed in determining that pre-operative antibiotic administration does decrease the bacterial burden of staphylococcal PJI. The objective of Phase 2 is to determine how presurgical antibiotic therapy affects a) the spatial dissemination of bacteria in PJI and b) the local and systemic host inflammatory response. Phase 2 will be the focus for the Medical Student Summer Research Fellow. [The objective of Phase 3 (if time permits) is to determine if presurgical antibiotic therapy improves the outcome of surgical resection and antibiotic spacer insertion for treatment of PJI in a mouse model.]
Female athlete ski injuries are high energy injuries affecting multiple structures. Female and male skiers have similar patterns of injury. Anterior cruciate ligament ruptures are the highest prevalence injury.
The objective of this study is to digitally register and characterize hip anatomy in femoroacetabular impingement syndrome. Specifically, we will delineate normal from abnormal bone in both subspine impingement and cam impingement.
An App guided position measurement of the pelvis accurately predicts axial rotation and pelvic inclination of the pelvis.
Reverse shoulder arthroplasty is successful at eliminating pain and improving function for patients with shoulder arthritis and a dysfunctional rotator cuff. Traditionally, this prosthesis is designed such that the center of shoulder rotation is medial to the glenoid implant so that shear forces are minimized and failures are reduced. Recent studies have suggested that there may be functional benefits to lateralization, such as improved internal and external rotation, better stability, better shoulder contour, and reduced scapular notching. However, the effects of lateralization on the reactive forces across the implant are poorly understood. This study will evaluate the forces across a reverse total shoulder replacement with varying degrees of lateralization. This will be accomplished with a custom-made shoulder simulator that can replicate muscle forces across the joint. Using this simulator, we plan to determine the joint reactive forces across the implant with varying degrees of lateralization. This data will be used to develop a finite element computer model to determine how various glenoid designs can counteract these forces to ensure implant longevity. The student will be responsible for assisting in cadaver dissection and reverse total shoulder implantation, specimen preparation, running of the simulator, data acquisition, data analysis, and preparation of a manuscript. The student will work closely with a surgeon, research engineer and a doctoral student and will have exposure to senior surgeons and scientists. The only requirement for the position is an enthusiasm for the work at hand.
Biomechanical research will be conducted to compare our novel anatomical interference screw reconstruction of the scapholunate interosseous ligament (SLIL) to the modified Brunelli technique (MBT). We believe that an anatomic reconstruction of the SLIL, secured with interference screws, can provide sufficient stability between the scaphoid and lunate without compromising wrist ROM. It is hypothesized that our interference screw reconstruction technique will restore static scapholunate (SL) relationships (as measured by SL interval and SL angle) and intact wrist kinematics as well as the MBT reconstruction. The medical student will work with the investigator during cadaver dissection of the ligaments, ligament reconstruction, and biomechanical testing of the intact and reconstructed ligaments. The medical student may conduct literature reviews relevant to the project. Research findings will impact surgical approaches to SLIL reconstruction. In addition, the medial student will accompany the investigator to office hours and surgery to better understand how concepts investigated during biomechanical research may ultimately translate into practice.
Clinical examination of the ACL-injured and -reconstructed knee is severely limited. For example, a uniplanar test of anterior laxity shows no correlation with patient outcome. In contrast, the pivot shift exam, a test of the rotational stability of the knee, is closely associated with patient outcomes. In fact, positive findings with this exam correlate with compromised function and may indicate increased risk of osteoarthritis (OA). Unfortunately, this exam is qualitative and subjective. Lack of quantitative and objective clinical measurement of knee rotations in large cohorts of patients severely hampers clinical research aimed at comparative effectiveness of ACL reconstruction techniques for public health recommendations, and impairs the ability to determine the pathomechanics that link ACL injury and reconstruction to OA. Our group is working to overcome this limitation by developing a new measurement instrument, which will provide objective, quantitative measurement of knee rotations. As a first step in the clinical implementation of this new measurement instrument, we will conduct an in vitro study to assess its safety, accuracy and reliability. The summer student will be involved in all aspects of this study including specimen preparation and dissection, and data collection and analysis.
Initial fixation of prosthetic implants to bone relied upon the use of acrylic bone cement for fixation. Unfortunately, over time the cement would fatigue and lead to prosthetic loosening. The development of biologic fixation of implants to bone with the use of porous implants has lead to improved durability. Recently, there has been a movement to change the shape and texture of the porous implant surface by using more complex 3-dimensional configuration with the hope of enhanced fixation. Whether this leads to improved fixation is not known. The assessment of the extent of bone ingrowth into traditional porous implants has been determined by detecting back-scattered electrons (BSE) during scanning electron microscopy, an accurate but timely and costly technique. These 1st generation porous implants were largely made out of titanium alloy and were compatible with this technique. The recent shift to the 3-D surfaces has employed implants made of both titanium and tantalum, another biologically friendly metal. Unfortunately, the use of BSE techniques to assess fixation has proven difficult with implants made from tantalum in addition to the time and cost associated. We have recently started investigating the use of a high resolution optical microscope combined with histological staining techniques to determine if the same metrics for evaluation of bone ingrowth, namely extent and depth of penetration of bone into the porous coating, could be attained with this instrument.
Retrieval analysis is valuable in assessing in vivo surface damage on orthopaedic devices and contributes to understanding the responsible mechanisms and subsequently improving implant materials and designs. Damage assessment traditionally employs subjective techniques to grade damage on the implant’s surface. Digital microscopy has improved our ability to localize and quantify damage, although it is unable to measure volumetric removal of material as a function of this damage. Laser scanning technology fills this niche, but provides lower resolution and minimal photographic evidence. Recent advances in imaging enables laser scan data to be rendered with photographs (photorendering), thus combining the strengths of both techniques. We have recently begun using similar methods to improve our capabilities to assess damage in implants and potentially correlate volumetric changes with the damage assessment. While the methodology of combining microscopy to laser scan data works anecdotally, more work remains in testing the robustness of fit and circumventing limitations in both the microscopy data and the software used to stitch images together. As important, the improved resolution images provided by the microscope offers an opportunity to automate damage assessment, yielding damage mapped images that can also be overlayed on the laser scan data. This may provide a means to better quantify observed damage and yield meaningful correlations with volumetric changes due to wear and deformation of the implant.
This research project is a biomechanical study that will utilize 3D motion analysis to investigate the relationship between wrist range of motion and wrist function. The long term goal of this work is to develop an objective clinical outcome measure for wrist pathologies that accurately reflects wrist function. 3D motion analysis will be used to quantify wrist circumduction, defined as a smooth circular wrist motion along the boundary limits of the wrist. Results for both normal and individuals with restricted motion will be correlated with performance of various wrist dependent functional tasks.
Our objective is to quantify the change in midfoot joint surface interactions in hallux valgus patients compared to matched controls on weightbearing CT scans. We hypothesize that hallux valgus patients will have significantly increased mean and peak distances as well as decreased joint coverage at the C1-C2 intercuneiform as a measure of increased midfoot instability in hallux valgus patients.
Our objective in this study is to validate our intra-pelvic THA implantation. We hypothesize that an appropriately constructed intrapelvic THA model will exactly mimic the position of conventionally implanted THA and provide similar torque at impingement while allowing for preservation of the soft tissue capsule around the hip.
Reverse Shoulder Arthroplasty (RSA) is been used extensively, but despite the good clinical results, concerns remain about impingement and limited range of motion post-operatively. Even if multiple studies have investigated the intra-articular impingement (contact of the polyethylene cup with the inferior glenoid rim), extra-articular impingement (contact of the humerus to the acromion or coracoid) is still not well understood. The overall objective of this investigation is to study how the shape and size of the acromion and coracoid can affect shoulder range of motion and extra-articular impingement in standardized movements and Activities of Daily Living (ADLs).
Symptomatic proximal migration of the index metacarpal has been reported as a complication after partial or full trapezoid excision for scaphoid-trapezium-trapezoid (STT) joint arthritis. There is anatomic variability in the anatomy of the index metacarpal base in terms of articulation with the capitate and the trapezoid which may affect risk of proximal migration after partial trapezoid excision. Index metacarpals with more articular contact area with the capitate will have less risk of proximal migration after partial or full trapezoid excision for STT arthritis.
To evaluate estimates of ACL force using a physics-based computer model with physical measurements of ACL force from a cadaver model.
Bone Morphogenetic Protein-2 (BMP-2) is a popular adjunct for spine fusion. Although it has only been FDA-approved for select uses in the lumbar spine, it has been commonly used in off-label indications and locations. This study aimed to assess BMP-2 usage and complication rates at a high-volume tertiary orthopedic institute.
Posterior spinal surgery for degenerative scoliosis can be concerning due to the potential risk of exacerbating iatrogenic deformity caused by the disruption of paravertebral muscles in the lumbar spine, which may lead to unfavorable outcomes. Minimally invasive (MI) lumbar decompression has been a treatment option for these patients with stenosis. However, the clinical outcomes of MI decompression in patients with severe Cobb angle remain uncertain. The aim of this study was to investigate the clinical outcomes of MI lumbar decompression in patients with degenerative scoliosis exceeding 20 degrees.
The purpose of this study is to provide updated analyses on return-to-play (RTP) rates and performance outcomes following conservative and operative treatment for lumbar disc herniation (LDH) among National Basketball Association (NBA) players, while providing novel insight into the implications of LDH and treatment on contracts and cost of recovery. This study will also feature expert opinions on nonoperative and operative approaches to managing LDHs in professional basketball players from a physiatrist and an orthopaedic spine surgeon who have extensive experience with treating NBA players.
The primary objective is to determine utilities related to health states encountered with the unicameral bone cyst diagnosis.
The objective of this study is to calculate the native laxities of a consecutive series of knees that underwent TKA using the Mako platform and to develop a classification system based on this data.
The overall goal of this proposal is to investigate several novel aspects of bone quality, including microarchitecture and material properties, in patients undergoing cementless total knee arthroplasty. We will use new techniques available at HSS, high resolution peripheral quantitative computed tomography which measures true 3-D volumetric bone density and microarchitecture and Fourier transform infrared spectroscopy which measures the material properties of bone. These techniques wil enable us to obtain novel information about local bone quality and how it relates to outcomes after knee arthroplasty.
The purpose of this study is to compare the accuracy of INBONE implants using patient specific instrumentation (PSI) with PROPHECY technology to using INBONE implants using a jig for accuracy for total ankle arthroplasty (TAA).
Based on clinical experience and due to the proximity of the tendon to the typical location of the cysts, patients with occult dorsal ganglion cysts appear to have an exaggerated tenodesis response of their index finger. This manifests as increased index finger extension compared with the remaining fingers. We hypothesize that a positive tenodesis effect will be a reliable clinical exam for the presence of an occult ganglion cyst.
This study aims to evaluate the novel use of an accelerometer and impact load sensor as a beneficial resource in the recovery of total hip arthroplasty, while also identifying the timepoint during recovery that symmetry is restored between operative and non-operative limbs.
The purpose of this study is to examine primary surgical intervention for acute patellofemoral instability in skeletally immature patients with trochlear dysplasia.
To evaluate short-term outcomes and complication rates in patients with medial compartment knee osteoarthritis (OA) treated with an implantable shock absorber (ISA) system.
Complex spine surgery varies remarkably in terms of surgical time. The first aim of this study is to determine the time spent on various surgical steps and test how they differ by surgeon experience. The second aim is to determine patient level factors that influence time spent at each step. The third aim is to determine whether time spent influences outcomes.
We hypothesize that patients with multidirectional shoulder instability who have failed conservative management treated with open shoulder capsulorrhaphy with Achilles allograft augmentation will have low rates of recurrent instability and revision surgery at short- to mid-term follow-up (1 to 7 years). We believe that they will report improvements in subjective shoulder stability and PROMs as well.
Determine if day-of-surgery preoperative PT-administered gait/stair training and postoperative ambulation with PACU nursing allows for safe same-day TJAdischarge. Adverse events, patient satisfaction, and patient-reported outcome measures (PROM) associated with this discharge protocol will also be evaluated.
The goal of this OREF-funded study is to develop a patient reported outcomes measure (PROM) survey, which is specific for patients who have undergone total knee arthroplasty (TKA).
Patients who underwent tendon fenestration with PRP for tennis elbow have good clinical outcomes at 2 years post procedure.
The primary objective of this study is to compare the degree of patient-reported improvement following primary total knee arthroplasty (TKA) as measured by the Knee Injury and Osteoarthritis Outcome Score for Joint Replacement (KOOS JR) minimum clinically important difference (MCID), substantial clinical benefit (SCB), and patient acceptable symptom state (PASS) for those with mild radiographic osteoarthritis (Kellgren-Lawrence [KL] grade 0-2) which required MRI for confirmation versus patients with severe radiographic (KL grade 4) osteoarthritis.
TKA/THA readmissions in 30 days in SLE patients.
The purpose of this study is to analyze the sound levels present in the operating room during spine surgery and determine if they violate a healthy threshold that could lead to noise-induced hearing loss (NIHL) in the spine surgeon over time.
Vertebral skeletal stem cells (vSSCs) have been a topic of recent scientific interest, as studies have shown that vSSCs may be distinct from other skeletal stem cells and uniquely contribute to vertebral metastasis. We believe that two distinct lineages of vSSCs contribute to the formation of the vertebral body (ventral and dorsal portion), and that the ventral portion experiences a preferential loss of bone mineral density (BMD) as average BMD decreases or with long-term steroid use.
The goal of this project is to develop an AI deep-learning algorithm that automates a tibial 3D CT segmentation in order to more effectively assess bone defects and plan reconstruction techniques.
The purpose of this study is to evaluate the response of nerves to different nerve wraps in a mouse model with an induced scarred tissue bed. We will be using IL-4/IL-10 null mice, which show increased scarring, to evaluate the sciatic nerve response to three nerve wraps following the creation of a scarred tissue bed. Muscular tissues surrounding the sciatic nerves of both left and right rear legs will be dissected to expose the nerve; each nerve will be isolated out of the tissue bed, and wrapped with either AxoGuard (porcine submucosa), NeuraWrap (bovine type I collagen), vein wrap, or no wrap (sham control). The rats will be sacrificed at 2 month and 4 month intervals. Endpoint testing will include assessment of neovascularization, adhesion, scarring, nerve gliding, nerve histology and nerve function. The student will be able to participate in study design, assisting with the animal surgery, endpoint testing, and manuscript preparation.
Hypotheses: 1. Excessive graft strain will adversely affect healing of a tendon graft in a bone tunnel. 2. Novel MRI pulse sequences will allow detection of differences in graft collagen ultrastructure in response to varying levels of strain loading. Methods: ACL reconstruction will be performed in a rabbit model. We have verified that we can induce different levels of graft strain by varying the location of the femoral tunnel and knee flexion angle for graft fixation. We then use an external fixator on the knee to control post-operative knee motion. The independent variable (graft strain) is controlled by knee motion done using a custom-designed motion device with the animal under anesthesia. We vary the magnitude, frequency, and time of onset of strain loading. The primary outcome measure is MRI appearance of the graft (quantitative MRI- measurement of T2 relaxation time and T1 rho). Secondary outcome measures are graft healing to bone (histology) and graft attachment strength and stiffness (biomechanical testing). Role of Student: The student will participate in all aspects including animal surgery, specimen harvest, tissue dissection, biomechanical testing, data analysis, and manuscript preparation. The student will be exposed to the research environment in our laboratory, which includes senior scientists, post-doctoral fellows, technicians, and other students. They will be exposed to numerous basic laboratory techniques, and will also participate in regular laboratory meetings.
Heterotopic ossification (HO) is a recognized complication of arthroplasty which can cause pain and significantly limit function. HO is a well recognized complicates total hip arthroplasty (THR) in patients with diseases such as ankylosing spondylitis, which are characterized by the formation of new bone. Psoriatic arthritis (PsA) is also a form of arthritis, more common than ankylosing spondylitis, in which new bone is formed. Although it is not usually associated with increased risk of HO, preliminary work by our group suggests HO may be increased in patients with psoriatic arthritis, and possibly in patients with cutaneous psoriasis (PsC) alone. Although medications such as non-steroidal anti-inflammatory drugs (NSAIDS) can affect HO rates, it is unclear how often these regimens are actually used, and how effective they are in psoriatic patients. Our study will investigate the prevalence of HO in patients with psoriatic arthritis and psoriasis, and clarify the effect of HO and HO prophylactic regimens on post-operative pain and function. The role of the student in this project will be to review radiographs of patients with validated diagnosis of PsA and PsC after THR, and grade HO using the Brooker classification. Additional information will be gathered by chart review to determine the exposure in each case to NSAIDS, and to determine if prophylaxis for HO was administered.
Applying tensile and compressive forces to tissue engineered cartilage will generate arcade-like alignment in the collagen fibers.