Publications

Healthy shoulder function requires the coordination of the rotator cuff muscles to maintain the humeral head's position in the glenoid. While glenohumeral stability has been studied in various settings, few studies have characterized the effect of dynamic rotator cuff muscle loading on glenohumeral translation during shoulder motion. We hypothesize that dynamic rotator cuff muscle activation decreases joint translation during continuous passive abduction of the humerus in a cadaveric model of scapular plane glenohumeral abduction. The effect of different rotator cuff muscle activity on glenohumeral translation was assessed using a validated shoulder testing system. The Dynamic Load profile is a novel approach, based on musculoskeletal modeling of human subject motion. Passive humeral elevation in the scapular plane was applied via the testing system arm, while the rotator cuff muscles were activated according to the specified force profiles using stepper motors and a proportional control feedback loop. Glenohumeral translation was defined according to the International Society of Biomechanics. The Dynamic load profile minimized superior translation of the humeral head relative to the conventional loading profiles. The total magnitude of translation was not significantly different (0.805) among the loading profiles suggesting that the compressive forces from the rotator cuff primarily alter the direction of humeral head translation, not the magnitude. Rotator cuff muscle loading is an important element of cadaveric shoulder studies that must be considered to accurately simulate glenohumeral motion. A rotator cuff muscle activity profile based on human subject muscle activity reduces superior glenohumeral translation when compared to previous RC loading profiles.

Background: This study intends to summarize the causes, clinical examination, and treatments of scapular dyskinesis (SD) and to briefly investigate whether alteration can be managed by a precision rehabilitation protocol planned on the basis of features derived from clinical tests. Methods: We performed a comprehensive search of PubMed, Cochrane, CINAHL and EMBASE databases using various combinations of the keywords "Rotator cuff", "Scapula", "Scapular Dyskinesis", "Shoulder", "Biomechanics" and "Arthroscopy". Results: SD incidence is growing in patients with shoulder pathologies, even if it is not a specific injury or directly related to a particular injury. SD can be caused by multiple factors or can be the trigger of shoulder-degenerative pathologies. In both cases, SD results in a protracted scapula with the arm at rest or in motion. Conclusions: A clinical evaluation of altered shoulder kinematics is still complicated. Limitations in observing scapular motion are mainly related to the anatomical position and function of the scapula itself and the absence of a tool for quantitative SD clinical assessment. High-quality clinical trials are needed to establish whether there is a possible correlation between SD patterns and the specific findings of shoulder pathologies with altered scapular kinematics.

Osteosarcoma is the most common primary malignant bone tumor in children. Patient survival with osteosarcoma is heavily influenced by the response to chemotherapy, measured by tumor necrosis upon histological analysis. Unfortunately, response is not measurable until the time of surgery and therefore modifications to chemotherapy protocol are only made after several weeks of treatment and surgery. Osteosarcoma tumors often demonstrate increased mineralization following the onset of chemotherapy. Furthermore, it has been hypothesized that this mineralization-apparent on radiographs-may correlate with chemotherapy response, however, this has not been demonstrated with qualitative visual evaluation. The ability to non-invasively measure a patient's response to chemotherapy using plain radiographs, which is currently included in the normal clinical workflow, would guide the medical oncologists to tailor treatment for patients with osteosarcoma. After obtaining appropriate multi-center institutional review board approvals, we identified 31patients that possess a pair of pre-and post-chemotherapy radiograph along with the necrosis measure. The images were digitized scans of physical radiographs between 1999 and 2013. Software was designed to measure the signal intensities in the tumor, a region of the soft tissue, air, and healthy bone. The tumor signals were normalized based on the random combination of air, soft tissue or bone, by subtraction or division. The differences in tumor signal between pre-and post-image were plotted against the percent necrosis determined by histological analysis. Different combinations of the normalization methods were compared 2based on the slope, coefficient of determination (R2) and Pearson correlation coefficient (ρ).

* Arthrofibrosis is a pathologic condition that is characterized by excessive periarticular scar-tissue formation. Arthrofibrosis may occur secondary to injury, surgical trauma, hemarthrosis, or infection, or it may occur idiopathically.* The pathogenesis of arthrofibrosis is incompletely understood but involves the dysregulation of normal reparative pathways, with transforming growth factor-beta (TGF-[beta]) as a principal mediator.* Current treatment options for arthrofibrosis primarily involve physiotherapy, operative manipulation, and surgical debridement, all with imperfect results.* Currently, there are no pharmacologic treatment options for arthrofibrosis. This has prompted increased investigational interest in the development of antifibrotic intra-articular therapies.

BACKGROUND: There is a lack of evidence regarding the optimum extensor-sided fixation method for medial patellofemoral ligament (MPFL) reconstruction. There is increased interest in avoiding patellar drilling via soft tissue-only fixation to the distal quadriceps, thus reconstructing the medial quadriceps tendon-femoral ligament (MQTFL). The biomechanical implications of differing extensor-sided fixation constructs remain unknown.

HYPOTHESIS: The null hypothesis was there would be no differences between traditional MPFL reconstruction and MQTFL reconstruction with respect to resistance to lateral translation, patellar position, or patellofemoral contact pressures.

STUDY DESIGN: Controlled laboratory study.

METHODS: Nine adult knee specimens were mounted on a jig that applied static, physiologic loads to the quadriceps tendons. Patellar position and orientation, knee flexion angle, and patellofemoral pressure were recorded at 8 different flexion angles between 0° and 110°. Additionally, a lateral patellar excursion test was conducted wherein a load was applied directly to the patella in the lateral direction with the knee at 30° of flexion and subjected to 2-N quadriceps loads. Testing was conducted under 4 conditions: intact, transected MPFL, MQTFL reconstruction, and MPFL reconstruction. For MQTFL reconstruction, the surgical technique established by Fulkerson was employed. For MPFL reconstruction, a traditional technique was utilized.

RESULTS: The patellar excursion test showed no significant difference between the MQTFL and intact states with respect to lateral translation. MPFL reconstruction led to significantly less lateral translation (P < .05) than all other states. There were no significant differences between MPFL and MQTFL reconstructions with respect to peak patellofemoral contact pressure. MPFL and MQTFL reconstructions both resulted in increased internal rotation of the patella with the knee in full extension.

CONCLUSION: Soft tissue-only extensor-sided fixation to the distal quadriceps (MQTFL) during patella stabilization appears to re-create native stability in this time 0 cadaver model. Fixation to the patella (MPFL) was associated with increased resistance to lateral translation.

CLINICAL RELEVANCE: Evolving anatomic knowledge and concern for patellar fracture has led to increased interest in MQTFL reconstruction. Both MQTFL and MPFL reconstructions restored patellofemoral stability to lateral translation without increasing contact pressures under appropriate graft tensioning, with MQTFL more closely restoring native resistance to lateral translation at the time of surgery.

PURPOSE: Great effort has been placed on determining the optimal surgical treatment for trapeziometacarpal joint arthritis (TMA). However, a paucity of literature exists concerning the optimal timing of surgical intervention. We hypothesized that an increased duration of TMA symptoms before operative intervention would negatively affect surgical outcomes.

METHODS: We performed a retrospective review on 109 adult patients with 121 joints with symptomatic TMA treated with trapeziectomy and ligament reconstruction with tendon interposition (LRTI) from 2006 to 2017. Outcome measures included Quick-Disabilities of the Arm, Shoulder, and Hand (QuickDASH) score, complication rates, and surgical revision rates.

RESULTS: Among 109 patients, average QuickDASH score at initial presentation was 41.1 ± 17.9. Patients had symptoms of TMA for an average of 3.2 years (median, 2.1 years) before undergoing operative intervention. Patients were divided into 2 groups: those with symptoms less than 2 years and those with symptoms greater than 2 years. Patients who underwent LRTI after less than 2 years of symptoms achieved a significantly greater degree of improvement in the QuickDASH score compared with patients with symptoms greater than 2 years (26.2 vs 5.3).

CONCLUSIONS: Patients with less than 2 years of symptomatic TMA before LRTI can expect the greatest improvement in patient-reported disability impairment compared with those with more than 2 years of symptoms. This can be used to counsel patients regarding the optimal timing of surgery if nonsurgical treatment has failed to provide durable symptomatic relief.

TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.

The global burden of musculoskeletal trauma is high. There is a need to improve access to safe, high-quality surgery in many low- and middle-income countries (LMICs). Numerous initiatives have taken aim at solving this underlying shortage in surgical care, including mission trips, academic programs, and international collaborations. However, much work remains to be done in LMICs compared with high-income countries (HICs). In HICs, the field of hand surgery has grown partially owing to the rigorous application of clinical research to examine outcomes and determine best practices. Patient-reported outcome measures (PROMs) have a key role as a valid patient-centered method of capturing symptoms and well-being. They have substantial promise in LMICs to understand patient symptom severity and quality of life better, monitor treatment success or failure, determine cost-effectiveness of procedures, and guide capacity building. Contextually appropriate PROMs can improve routine follow-up in LMICs and advance the practice and study of hand surgery worldwide.

BACKGROUND: As rhinoplasty techniques have evolved to more extensive dissections, the incidence of iatrogenic deformities, such as alar rim retraction, has risen. Its mechanism is presently unknown. This study examined the microscopic anatomy of the nasal ala to define architectural support elements at the histologic level to determine why rhinoplasty dissection creates such deformities.

METHODS: Eight cadaveric noses were harvested and sectioned through the soft triangle and ala. Various tissue stains were performed. Slides were examined using light microscopy. Anatomical features pertaining to cartilage, skin, mucosa, elastic fibers, and muscle were documented.

RESULTS: Four male and four female noses were sectioned. The median cadaver age was 64 years (range, 47 to 83 years). On Elastica van Gieson stain, distinct elastic fibers span from the vestibular lining to the caudal margin of the lower lateral cartilage, and from the caudal edge of the lower lateral cartilage to the external alar skin. In the nasal ala midsection, trichrome stains reveal that skeletal muscle is located far beyond the lower lateral cartilage, close to the free alar margin. The soft triangle shows a distinct microanatomical structure, with heavy longitudinal condensations of elastin. These histologic findings have not been previously reported.

CONCLUSIONS: A distinct anatomical alar wall endoskeleton has been identified. It is obligatorily disrupted by specific rhinoplasty maneuvers when dissection is carried out over the lateral crura and into areas without cartilaginous support. This microanatomy may explain factors that contribute to postoperative alar wall retraction. Leaving this area undisturbed or performing adjunctive measures with rhinoplasty can provide structural support to the external valves, thus minimizing the risk of deformity.

BACKGROUND: Survival following a diagnosis of osteosarcoma is correlated strongly with response to chemotherapy. Mineralization changes seen on radiographs have been hypothesized to correlate with chemotherapy response, however, this has never been analyzed using modern techniques.

METHODS: Retrospective review of radiographs obtained before and after neoadjuvant chemotherapy was performed for 31 patients with high-grade, conventional osteosarcoma. Pre-chemotherapy (PreC) images and post-chemotherapy (PostC) images were co-registered. Tumor luminance measurements were normalized based on the non-tumor bone and then the relative change in tumor mineralization were measured.

RESULTS: Mean luminance values for pre-chemotherapy non-tumor-affected bone and tumor were 0.63±0.12 and 0.65±0.12, respectively. Mean values for PostC non-tumor-affected bone were 0.59±0.14 and 0.64±0.10, respectively. Once normalized, osteosarcoma mineralization change showed a statistically significant moderate correlation-Pearson correlation coefficient (ρ) of 0.36 (P=0.038)-with the tumor necrosis value.

CONCLUSIONS: Moderate, positive correlation was found between osteosarcoma mineralization change during chemotherapy and chemotherapy response. Further work is required to determine if these findings are prognostic by identifying best practice for image analysis and repeating this work with prospectively acquired digital radiographs using uniform technique and phantom normalization.

BACKGROUND: Phrenic nerve palsy is a rare complication of cervical spine surgery. There are no previously reported cases of unilateral diaphragmatic paralysis following posterior cervical spine surgery. Here, we present a case of a 69 year-old Caucasian male with severe cervical stenosis with myelopathy who underwent posterior spinal instrumentation and fusion (PSIF) from C2 to T2, with laminectomies at C3-C7.

OUTCOME: The patient developed respiratory distress post-operatively and was found to have an elevated hemidiaphragm secondary to phrenic nerve palsy. He was treated with respiratory support, with significant improvement in dyspnea. He was also noted to have a left C5 palsy affecting his deltoid function and proximal upper extremity sensation which gradually improved.

CONCLUSIONS: This is the first reported case of unilateral diaphragmatic paralysis causing dyspnea due to phrenic nerve palsy following cervical spine surgery. This rare complication should be kept in mind when assessing any patient with respiratory distress following cervical spine surgery.