Michael Dohm

Biomechanical evaluation of various forms of fixation of transverse patellar fractures

Summary: A study was undertaken to evaluate the strength and ease of application of four different forms of patellar fracture fixation. Modified tension band, screw fixation, Lotke longitudinal anterior band (LAB), and Magnusson wiring were examined using a Materials Testing System. Using cadaver lower extremities, the tibia was mounted in a fixed base and the tibiofemoral joint was fixed at 36°. Tension was applied to the patella through the quadriceps tendon and fracture displacement was measured with linear motion transducers. Based on the results, we recommend screw fixation for transverse patellar fractures in patients with adequate bone stock. In patients with patellar fractures with comminution and/or osteopenia, modified tension band fixation is recommended. Simple wiring techniques alone may not provide sufficient fixation to allow immediate range of motion.

A biomechanical evaluation of three forms of internal fixation used in ankle arthrodesis.

A biomechanical study was undertaken to evaluate the relative stability of three types of internal fixation used for ankle arthrodesis. Crossed screw fixation, RAF fibular strut fixation, and T-plate fixation were tested in 30 cadaver ankles using an MTS machine. T-plate fixation consistantly provided the stiffest construct when compared with the other types of fixation. Failure occurred by distraction of bony surfaces, posterior to the plane of fixation, in the crossed screw and RAF groups. In contrast, failure in the T-plate group occurred through compression of bone anterior to the midcoronal plane of the tibia. Although the stability of fixation is only one factor in determining the success or failure of ankle arthrodesis, the results of this study would support T-plate fixation over the other forms tested.

Outcome Domains and Measures in Total Joint Replacement Clinical Trials: Can We Harmonize Them? An OMERACT Collaborative Initiative

Objective. To develop a plan for harmonizing outcomes for people undergoing total joint replacement (TJR), to achieve consensus regarding TJR outcome research. Methods. The TJR working group met during the 2014 Outcome Measures in Rheumatology (OMERACT) 12 meeting in Budapest, Hungary. Multiple conference calls preceded the face-to-face meeting. Brief presentations were made during a 1.5-h meeting, which included an overview of published systematic reviews of TJR trials and the results of a recent systematic review of TJR clinical trial outcome domains and measures. This was followed by discussion of potential core set areas/domains for TJR clinical trials (as per OMERACT Filter 2.0) as well as the challenges associated with the measurement of these domains. Results. Working group participants discussed which TJR clinical trial outcome domains/areas map to the inner versus outer core for core domain set. Several challenges were identified with TJR outcomes including how to best measure function after TJR, elucidating the source of the pre- and post-TJR joint pain being measured, joint-specific versus generic quality of life instruments and the importance of patient satisfaction and revision surgery as outcomes. A preliminary core domain set for TJR clinical trials was proposed and included pain, function, patient satisfaction, revision, adverse events, and death. This core domain set will be further vetted with a broader audience. Conclusion. An international effort with active collaboration with the orthopedic community to standardize key outcome domains and measures is under way with the TJR working group. This effort will be further developed with new collaborations.

Gait behaviors as an objective surgical outcome in low back disorders: A systematic review

BACKGROUND Objective motor performance measures, especially gait assessment, could improve evaluation of low back disorder surgeries. However, no study has compared the relative effectiveness of gait parameters for assessing motor performance in low back disorders after surgery. The purpose of the current review was to determine the sensitive gait parameters that address physical improvements in each specific spinal disorder after surgical intervention. METHODS Articles were searched with the following inclusion criteria: 1) population studied consisted of individuals with low back disorders requiring surgery; 2) low back disorder was measured objectively using gait assessment tests pre- and post-surgery. The quality of the selected studies was assessed using Delphi consensus, and meta-analysis was performed to compare pre- and post-surgical changes. FINDINGS Thirteen articles met inclusion criteria, which, almost exclusively, addressed two types of spinal disorders/interventions: 1) scoliosis/spinal fusion; and 2) stenosis/decompression. For patients with scoliosis, improvements in hip and shoulder motion (effect size=0.32-1.58), energy expenditure (effect size=0.59-1.18), and activity symmetry of upper-body muscles during gait were present after spinal fusion. For patients with spinal stenosis, increases in gait speed, stride length, cadence, symmetry, walking smoothness, and walking endurance (effect size=0.60-2.50), and decrease in gait variability (effect size=1.45) were observed after decompression surgery. INTERPRETATION For patients with scoliosis, gait improvements can be better assessed by measuring upper-body motion and EMG rather than the lower extremities. For patients with spinal stenosis, motor performance improvements can be captured by measuring walking spatio-temporal parameters, gait patterns, and walking endurance.

Achieving Consensus on Total Joint Replacement Trial Outcome Reporting Using the OMERACT Filter: Endorsement of the Final Core Domain Set for Total Hip and Total Knee Replacement Trials for Endstage Arthritis

Objective. Discussion and endorsement of the OMERACT total joint replacement (TJR) core domain set for total hip replacement (THR) and total knee replacement (TKR) for endstage arthritis; and next steps for selection of instruments. Methods. The OMERACT TJR working group met at the 2016 meeting at Whistler, British Columbia, Canada. We summarized the previous systematic reviews, the preliminary OMERACT TJR core domain set and results from previous surveys. We discussed preliminary core domains for TJR clinical trials, made modifications, and identified challenges with domain measurement. Results. Working group participants (n = 26) reviewed, clarified, and endorsed each of the inner and middle circle domains and added a range of motion domain to the research agenda. TJR were limited to THR and TKR but included all endstage hip and knee arthritis refractory to medical treatment. Participants overwhelmingly endorsed identification and evaluation of top instruments mapping to the core domains (100%) and use of subscales of validated multidimensional instruments to measure core domains for the TJR clinical trial core measurement set (92%). Conclusion. An OMERACT core domain set for hip/knee TJR trials has been defined and we are selecting instruments to develop the TJR clinical trial core measurement set to serve as a common foundation for harmonizing measures in TJR clinical trials.

Consensus on draft OMERACT core domains for clinical trials of Total Joint Replacement outcome by orthopaedic surgeons: a report from the International consensus on outcome measures in TJR trials (I-COMiTT) group

BackgroundThere are no core outcome domain or measurement sets for Total Joint Replacement (TJR) clinical trials. Our objective was to achieve an International consensus by orthopaedic surgeons on the OMERACT core domain/area set for TJR clinical trials.MethodsWe conducted surveys of two orthopaedic surgeon cohorts, which included (1) the leadership of international orthopaedic societies and surgeons (IOS; cohort 1), and (2) the members of the American Academy of Orthopaedic Surgeons’ Outcome Special Interest Group (AAOS-Outcome SIG), and/or the Outcome Research Interest Group of the Orthopaedic Research Society (ORS; cohort 2). Participants rated OMERACT-endorsed preliminary core area set for TJR clinical trials on a 1 to 9 scale, indicating 1–3 as domain of limited importance, 4–6 being important, but not critical, and 7–9 being critical.ResultsEighteen survey participants from the IOS group and 69 participants from the AAOS-Outcome SIG/ORS groups completed the survey questionnaire. The median (interquartile range [IQR]) scores were seven or higher for all six proposed preliminary core areas/domains across both groups, IOS and AAOS-Outcome SIG/ORS, respectively: pain, 8 [8, 9] and 8 [7, 9]; function, 8 [8, 8] and 8 [7, 9]; patient satisfaction, 8 [7, 9] and 8 [7, 8]; revision surgery, 7 [6, 9] and 8 [6, 8]; adverse events, 7 [5, 8] and 7 [6, 9]; and death, 7 [7, 9] and 8 [5, 9]. Respective median scores were lower for two additional optional domains: patient participation, 6.5 [5, 7] and 6 [5, 8]; and cost, 6 [5, 7] and 6 [5, 7].ConclusionsThis study showed that two independent surveys dervied from three groups of orthopaedic surgeons with international representation endorsed a preliminary/draft OMERACT core domain/area set for Joint Replacement clinical trials.

Towards Consensus on the Reporting of Core Outcome Domains in Total Joint Replacement Clinical Trials: The Derivation of the Preliminary Core Outcome Domain Set

Background: There is no consensus on how to report total joint replacement (TJR) trials. To our knowledge, core outcome domains for TJR clinical trials have not been defined. Our objective was to develop data-driven, consensus-based, preliminary recommendations for core outcome domains for TJR clinical trials. Method: We surveyed two groups of experts/stakeholders, who rated potential core outcome domains (mapped to Outcome Measures in Rheumatology Trials (OMERACT) filter 2.0 framework) for their relevance to TJR clinical trials during the 2014 American Academy of Orthopaedic Surgeons [AAOS] and Outcome Research Interest Group of the Orthopaedic Research Society (ORS) annual meeting and the 2014 OMERACT meeting. Ratings were on a 1-9 scale, 1-3 indicating domain of limited importance, 4-6 being important domain, and 7-9 being critically important domain. Results: Seventeen participants at the AAOS/ORS Outcomes Research Interest Group and 19 at OMERACT meeting completed the survey. At the two meetings, 73% and 36% were arthroplasty researcher/surgeons, 0% and 10% were patients and 58% and 31% were above 54 years, respectively. The following domains were rated as core outcome domains by both groups, with a median score of 7 and above (median score from AAOS/ORS vs. OMERACT): Joint pain (9 vs. 9), functional ability (8 vs. 9), joint-specific quality of life (8 vs. 7), patient satisfaction (7 vs. 8), revision surgery (8 vs. 7), adverse events (9 vs. 8), death (9 vs. 7.5), serious adverse events (8.5 vs. 8), reoperation (8 vs. 8), and cost (7 vs. 7). Conclusion: Stakeholders achieved consensus on preliminary core outcome domain set for TJR clinical trials. This set will be further vetted with multi-stakeholder input to achieve a fully endorsed TJR core outcome domain set.

Postural Balance Parameters as Objective Surgical Assessments in Low Back Disorders: A Systematic Review.

Balance assessments could render useful objective performance measures to evaluate the efficacy of low back surgeries, yet these assessments have not been collectively examined to determine longitudinal sensitivity across surgical interventions. The purpose of this review was to determine sensitivity of balance measurements for disparate spinal disorders after surgical intervention. We searched PubMed, Embase, Scopus, the Cochrane Library, Web of Science, and CINAHL. Articles were selected based on: (1) sample consisted of low back disorder individuals and (2) balance measurements were obtained both pre- and postsurgery. Most of the articles addressed 2 specific low back disorders: (1) adolescent idiopathic scoliosis/spinal fusion and (2) disc herniation/decompression surgery. For scoliosis patients, body sway increased (14-97%) immediately following surgery but gradually reduced (1-33%) approaching the 1-year post spinal fusion assessment. For patients with disc herniation, sway range, sway velocity, sway area, and sway variability all decreased (19-42%) immediately postsurgery. Balance assessments for adolescents with idiopathic scoliosis who underwent surgical intervention should be performed with visual occlusion, focus on time domain parameters, and evaluated with longer follow-up times. Patients with disc herniation who underwent decompression surgery should have balance assessments with visual deprivation, test conditions specifically addressing hip strategy, and correlation with pain.

Paravertebral spinal injection for the treatment of patients with degenerative facet osteoarthropathy: Evidence of motor performance improvements based on objective assessments

BACKGROUND This study examined short- and long-term improvements in motor performance, quantified using wearable sensors, in response to facet spine injection in degenerative facet osteoarthropathy patients. METHODS Adults with confirmed degenerative facet osteoarthropathy were recruited and were treated with medial or intermediate branch block injection. Self-report pain, health condition, and disability (Oswestry), as well as objective motor performance measures (gait, balance, and timed-up-and-go) were obtained in five sessions: pre-surgery (baseline), immediately after the injection, one-month, three-month, and 12-month follow-ups. Baseline motor performance parameters were compared with 10 healthy controls. FINDINGS Thirty patients (age=50 (14) years) and 10 controls (age=46 (15) years) were recruited. All motor performance parameters were significantly different between groups. Results showed that average pain and Oswestry scores improved by 51% and 24%, respectively among patients, only one month after injection. Similarly, improvement in motor performance was most noticeable in one-month post-injection measurements; most improvements were observed in gait speed (14% normal walking, P<0.02), hip sway within balance tests (63% eyes-open P<0.01), and turning velocity within the timed-up-and-go test (28%, P<0.02). Better baseline motor performance led to better outcomes in terms of pain relief; baseline turning velocity was 18% faster among the responsive compared to the non-responsive patients. INTERPRETATIONS Spinal injection can temporarily (one to three months) improve motor performance in degenerative facet osteoarthropathy patients. Successful pain relief in response to treatment is independent of demographic characteristics and initial pain but dependent on baseline motor performance. Immediate self-reported pain relief is unrelated to magnitude of gradual improvement in motor performance.

Surgical options for osteoporotic vertebral compression fractures complicated with spinal deformity and neurologic deficit

INTRODUCTION This paper describes surgical options for Osteoporotic vertebral compression fracture (OVCF) with acute flexible or chronic rigid kyphosis, and pseudarthrosis complicated with pain and neurologic deficit. METHODS This study has two components. a) A prospective clinical study of surgical treatment of 31 patients (age: 69±11 years) with either acute flexible or progressive pseudarthrotic kyphosis manifested with severe pain or neurological deficit between 2010 and 2014. Eleven patients exhibited neurocompression (Frankel B, C, D). Surgery consisted in indirect reduction, kyphoplasty, and short posterior instrumentation in 28 patients and multilevel instrumentation in three. b) The second component involved a literature search of OVCF complicated with acute or painful chronic deformities and neurologic deficit, managed with open surgical approach. RESULTS Indirect reduction, kyphoplasty and short posterior stabilization can restore satisfactory anatomic alignment and neurological deficit. Multilevel instrumentation was used for rigid long kyphosis. Complications were related to a) screw pull out and junctional kyphosis (4 patients) one of the patients also developed anterior migration of cement, b) cement leakage (4 patients). L5 radiculopathy occurred in one patient. The others remained asymptomatic. The literature review concluded that corpectomy with anterior, posterior or combined instrumentations is indicated for burst fractures, or rigid kyphosis with neurocompression. Prompt decompression with anatomical alignment may restore paraplegia. Complications were germane to osteoporotic bone predisposing to hardware loosening or cut out and dislodgement of instrumentation. DISCUSSION Neurologic deficit associated with fractures or progressive pseudarthrotic kyphosis effectively may respond to indirect postural reduction, kyphoplasty and posterior percutaneous short segment transpedicle instrumentation. For burst fractures and rigid chronic kyphosis corpectomy reconstructed with cages and anterior, or posterior or combined instrumentations can restore and maintain normal anatomy. The following guidelines for optimal surgical instrumentation have been established: To prevent screw loosening and junctional kyphosis the instrumentation should not end within the kyphotic segment. Screws for anterior instrumentation should penetrate the contralateral cortex. Multiple site of fixation or combined anterior and posterior instrumentations dissipate stresses at any one site. Augmentation of transpedicle screw fixation with cement is a sound technical principle. Cement should inserted in a doughy state with minimal pressure to prevent cement complications.