Running Following Hip Arthroplasty: A Systematic Review.

With improved implants and younger patients undergoing total hip arthroplasty (THA) and hip resurfacing arthroplasty (HRA), there are increased expectations to return to high-impact activities. Recommendations regarding return to running following hip arthroplasty remain unclear. A search of the PubMed database was conducted, and all publications referencing running following THA or HRA published between January 1, 2000, and September 1, 2020, were included in the systematic review. Patient demographics, surgical variables, activity measures, and revision rates were recorded for each study. A total of 225 unique citations were identified, of which four manuscripts met the eligibility criteria. Eighty-nine of 121 (73.6%) preoperative runners returned to running postoperatively. All four studies reported mean postoperative UCLA activity scores of at least nine. More patients returned to running following HRA than THA with lower rates of revision. Further research with longer postoperative follow-up is necessary to provide definitive recommendations for running following arthroplasty procedures. (Journal of Surgical Orthopaedic Advances 32(1):001-004, 2023).

Alignment in Medial Fixed-Bearing Unicompartmental Knee Arthroplasty: The Limb Has a Leg Up on the Component.

BACKGROUND: To assess how implant alignment affects unicompartmental knee arthroplasty (UKA) outcome, we compared tibial component alignment of well-functioning UKAs against 2 groups of failed UKAs, revised for progression of lateral compartment arthritis ("Progression") and aseptic loosening ("Loosening"). METHODS: We identified 37 revisions for Progression and 61 revisions for Loosening from our prospective institutional database of 3351 medial fixed-bearing UKAs performed since 2000. Revision cohorts were matched on age, gender, body mass index, and postoperative range of motion with "Successful" unrevised UKAs with minimum 10-year follow-up and Knee Society Score ≥70. Tibial component coronal (TCA) and sagittal (TSA) plane alignment was measured on postoperative radiographs. Limb alignment was quantified by hip-knee-ankle (HKA) angle on long-leg radiographs. In addition to directly comparing groups, a multivariate logistic regression examined how limb and component alignments were associated with UKA revision. RESULTS: In the Progression group, component alignment was similar to the matched successes (TCA 3.6° ± 3.5° varus vs 5.1° ± 3.5° varus, P = .07; TSA 8.4° ± 4.4° vs 8.8° ± 3.6°, P = .67), whereas HKA angle was significantly more valgus (0.3° ± 3.6° valgus vs 4.4° ± 2.6° varus, P < .001). Loosening group component alignment was also similar to the matched successes (TCA 6.1° ± 3.7° varus vs 5.9° ± 3.1° varus, P = .72; TSA 8.4° ± 4.6° vs 8.1° ± 3.9°, P = .68), and HKA was significantly more varus (6.1° ± 3.1° varus vs 4.0° ± 2.7° varus, P < .001). Using a multivariate logistic regression, HKA angle was the most significant factor associated with revision (P < .001). CONCLUSION: In this population of revised UKAs and long-term successes, limb alignment was a more important determinant of outcome than tibial component alignment. LEVEL OF EVIDENCE: Level III case-control study.

Unicompartmental Knee Arthroplasty: More Conversions, Fewer Complications Than Proximal Tibial Osteotomy in a Young Population.

BACKGROUND: Patients with isolated medial compartment osteoarthritis requiring surgical intervention generally have two surgical options: unicompartmental knee arthroplasty (UKA) and proximal tibial osteotomy (PTO). Outcomes of reoperation rates and survivorship are important for counseling patients on treatment options. METHODS: A retrospective, comparative cohort study was performed for a consecutive series of patients in the Military Health System who underwent either UKA or PTO between 2003 and 2018. All patients were between 18 and 55 years old and diagnosed with isolated medial compartmental arthritis. Cases with concurrent meniscal or cartilage procedures were included, while cases with concurrent ligament reconstruction were excluded. A minimum 2-year follow-up was required. The primary outcome was conversion to total knee arthroplasty, and the secondary outcome was reoperation for any reason. RESULTS: A total of 383 procedures were performed for isolated medial compartment arthritis in 303 patients (UKA 270, PTO 113). A multivariate analysis showed that PTO was associated with decreased risk of conversion to TKA compared to UKA (P = .0364). However, the reoperation due to complications was significantly higher in the PTO group (21.2% vs 2.2%; P ≤ .01). The 5-year conversion rate was 13.7% for UKA and 3.5% for PTO (P = .0033) with an average time to conversion of 3.1 years for UKA and 2.9 years for PTO (P = .7805). CONCLUSIONS: In young patients with isolated medial compartment arthritis, conversion rates to TKA are higher with UKA compared to PTO. However, overall reoperation rate is higher with PTO, secondary to complications and revision procedures. Overall survivorship is acceptable for both procedures.

The Impact of Coronal Alignment on Revision in Medial Fixed-Bearing Unicompartmental Knee Arthroplasty.

BACKGROUND: To better define the optimal alignment target for medial fixed-bearing unicompartmental knee arthroplasty (UKA), this study compares the postoperative mechanical alignment of well-functioning UKAs against 2 groups of failed UKAs, including revisions for progression of lateral compartment osteoarthritis ("Progression") and revisions for aseptic loosening or subsidence ("Loosening"). METHODS: From our prospective institutional database of 3351 medial fixed-bearing UKAs performed since 2000, we identified 37 UKAs revised for Progression and 61 UKAs revised for Loosening. Each of these revision cohorts was matched based on age at surgery, gender, body mass index, and postoperative range of motion with unrevised UKAs that had at least 10 years of follow-up and a Knee Society Score of 70 or greater without subtracting points for alignment ("Success" groups). Postoperative alignment was quantified by the hip-knee-ankle (HKA) angle measured on long-leg alignment radiographs. RESULTS: The mean HKA angle at 4-month follow-up for the Progression group was 0.3° ± 3.6° of valgus compared to 4.4° ± 2.6° of varus for the matched Success group (P < 0.001). For the Loosening group, the mean HKA angle was 6.1° ± 3.1° of varus versus 4.0° ± 2.7° of varus for the matched Success group (P < 0.001). CONCLUSIONS: Patients with well-functioning UKAs at 10 years exhibited mild varus mechanical alignment of approximately 4°, whereas patients revised for progression of osteoarthritis averaged more valgus and those revised for loosening or subsidence averaged more varus. The optimal mechanical alignment for medial fixed-bearing UKA survival with contemporary polyethylene is likely slight varus.

Comparison of Wound Complications and Deep Infections With Direct Anterior and Posterior Approaches in Obese Hip Arthroplasty Patients.

BACKGROUND: The purpose of this study was to compare the posterior approach (PA) with the direct anterior approach (DAA) among obese and nonobese total hip arthroplasty patients to determine if obese DAA patients have a higher risk of infection or wound complications compared with obese PA patients. METHODS: We retrospectively evaluated 4651 primary total hip cases performed via anterior approach or PA between 2009 and 2015. Patients were divided into 4 study groups based on approach and body mass index (BMI): (1) DAA <35 kg/m2, (2) DAA ≥35 kg/m2, (3) PA <35 kg/m2, and (4) PA ≥35 kg/m2. Infection rates and wound complications were compared. RESULTS: The rate of deep infection in groups 1 and 3 (nonobese anterior vs posterior) was 0.28% and 0.36%, respectively (P = .783); and in groups 2 and 4 (obese anterior vs posterior) was 2.35% and 2.7%, respectively (P = .80). The rate of wound complications between groups 1 and 3 (nonobese) was 1.0% and 0.3%, respectively (P = .005). Between groups 2 and 4 (obese), the rates of complications were 1.7% and 1.4%, respectively (P = 1.0). There was no difference in reoperation rates for wounds between groups 1 and 3 or between groups 2 and 4 (P = .217, P = .449). CONCLUSION: In the largest available series, there was no difference in deep infection rates between the 2 approaches. In the subset of obese patients with BMI ≥35 kg/m2, there was no increased risk of deep infection or wound complications in DAA patients compared with PA patients. However, anterior hip cases experienced higher rates of superficial wound complications compared with posterior cases across all BMIs.

Is Outpatient Unicompartmental Knee Arthroplasty Safe to Perform at an Ambulatory Surgery Center? A Comparative Study of Early Post-Operative Complications.

BACKGROUND: Unicompartmental knee arthroplasty (UKA) lends itself to the outpatient surgical setting. Prior literature has established a low rate of readmission and post-operative complications when performed in a hospital outpatient setting (HOP). To our knowledge, there have been no studies comparing complications of UKA performed at an ambulatory surgery center (ASC) and those in a HOP. METHODS: We retrospectively reviewed all patients who underwent outpatient UKA by a single surgeon from 2012 to 2016. In all 569 outpatient UKAs were performed: 288 in the ASC group and 281 in the HOP group. We compared the groups with regard to all complications within the first 90 days after surgery. RESULTS: Thirty minor and major complications occurred within 90 days (5.3%). There was no difference in the overall complication rate between groups (ASC 12, 4.2%; HOP 18, 6.4%) (P = .26). Day of surgery admission occurred once in the HOP group (0.4%) and did not occur in the ASC group (P = .49). There was 1 visit to the emergency department (ED) <24 hours from surgery in each group (ASC 0.3%, HOP 0.4%) (P = 1.0). ED visits occurred within 7 days in 3 ASC cases (1.0%) and 4 HOP cases (1.4%) (P = .72). Re-admissions in the first 90 days occurred in 5 ASC cases (1.7%) and 8 HOP cases (2.8%) (P = .41). CONCLUSION: UKA at an ASC has a low early postoperative complication rate without increased risk of re-admission or ED evaluation when compared to UKAs performed at a HOP.

Rapid Return to Braking After Anterior and Posterior Approach Total Hip Arthroplasty.

BACKGROUND: Little is known about the effect of surgical approach on return to braking after total hip arthroplasty (THA), and few studies have investigated braking after THA with modern surgical techniques and rehabilitation protocols. METHODS: In a prospective comparative design, we enrolled 65 patients who received right-sided primary THA at our institution from April 2018 through March 2020, 34 with a direct anterior approach (DAA) and 31 with a posterior approach (PA). Braking tests measuring brake reaction time (BRT) and brake pedal depression (BPD) were administered to patients preoperatively and at 1, 2, and 4 weeks postoperatively using a realistic driving simulator. BRT and BPD were compared between groups and preoperatively versus postoperatively using mixed-effects models. RESULTS: Preoperative BRT averaged 638 msec in the DAA group and 604 msec in the PA group (P = 0.31). At 1 week postoperatively, the DAA group had significantly prolonged BRT compared with preoperatively (694 msec, P = 0.02). No significant difference was observed in the PA group (633 msec, P = 0.31). Both groups had returned to baseline by 2 weeks, and both had significantly faster BRT at 4 weeks compared with preoperatively (583 msec for DAA, P = 0.01; 537 msec for PA, P < 0.001). BPD was similar between groups, and there were no significant differences between preoperative and postoperative BPD at any time point. CONCLUSIONS: With modern surgical techniques, BRT after right-sided THA returns to baseline levels approximately 2 weeks after surgery. There seems to be a quicker return to preoperative BRT observed in patients with a PA.

Periprosthetic Joint Infection in Patients With Arthroplasty Undergoing Perioperative Colonoscopy.

Importance: Periprosthetic joint infection (PJI) is a rare but devastating complication. Most patients undergoing total joint arthroplasty (TJA) also need routine screening colonoscopy, in which transient bacteremia may be a potential source for hematogenous PJI. Patients and surgeons must decide on an optimal time span or sequence for these 2 generally elective procedures, but no such guidelines currently exist. Objective: To evaluate associations of colonoscopy with the risk of post-TJA PJI for the development of clinical practice recommendations for colonoscopy screening in patients undergoing TJA. Design, Setting, and Participants: This retrospective cohort study of Military Health System (MHS) beneficiaries older than 45 years who underwent TJA from January 1, 2010, to December 31, 2016, used propensity score matching and logistic regression to evaluate associations of colonoscopy with PJI risk. Statistical analyses were conducted between January and October 2023. Exposure: Colonoscopy status was defined by Current Procedural Terminology code for diagnostic colonoscopy within 6 months before or 6 months after TJA. Main Outcomes and Measures: Periprosthetic joint infection status was defined by a PJI International Classification of Diseases code within 1 year after TJA and within 1 year from the post-TJA index colonoscopy date. Results: Analyses included 243 671 patients (mean [SD] age, 70.4 [10.0] years; 144 083 [59.1%] female) who underwent TJA in the MHS from 2010 to 2016. In the preoperative colonoscopy cohort, 325 patients (2.8%) had PJI within 1 year postoperatively. In the postoperative colonoscopy cohort, 138 patients (1.8%) had PJI within 1 year from the index colonoscopy date. In separate analyses of colonoscopy status within 6 months before and 6 months after TJA, younger age, male sex, and several chronic health conditions (diabetes, kidney disease, and pulmonary disease) were each associated with higher PJI risk. However, no association was found with PJI risk for perioperative colonoscopy preoperatively (adjusted odds ratio, 1.10; 95% CI, 0.98-1.23) or postoperatively (adjusted odds ratio, 0.90; 95% CI, 0.74-1.08). Conclusions and Relevance: In this large retrospective cohort of patients undergoing TJA, perioperative screening colonoscopy was not associated with PJI and should not be delayed for periprocedural risk. However, health conditions were independently associated with PJI and should be medically optimized.

Technical feasibility of uro-dynamic MRI study of voiding biomechanics: a pilot study.

INTRODUCTION: Dynamic volumetric MRI was used to non-invasively assess voiding biomechanics in a healthy male volunteer. METHODS: Using 3D Differential Subsampling with Cartesian Ordering (DISCO) Flex acquisition sequence, volumetric bladder images were obtained throughout the voiding effort. These were subsequently segmented using MIMICS. Segmented anatomical volumes were used to quantify total voided volume, post-void residual, volumetric displacement of urine over time, bladder neck angle, sphericity index, and prostatic urethral angle through the voiding effort. RESULTS: Bladder sphericity index correlated positively with flow rate. The greatest degree of bladder neck funneling correlated with the maximum urine flow rate. There was straightening of the prostatic urethral angle during voiding that also correlated positively with urine flow. CONCLUSION: This pilot study confirms the potential of dynamic MRI to provide non-invasive assessment of lower urinary tract anatomy and biomechanics during voiding.

Outcomes following cervical disc arthroplasty in an active duty military population.

Symptomatic cervical radiculopathy is a common problem in the active duty military population and can cause significant disability leading to limited duty status and loss of operational readiness and strength. Based on their increasing experience with cervical disc arthroplasty (CDA) in this unique patient population, the authors set out to further evaluate the outcomes and complications of CDA in active duty military patients. A retrospective review of a single military tertiary medical center was performed between August 2008 and August 2012 and the clinical outcomes of patients who underwent cervical disc arthroplasty were evaluated. There were 37 active duty military patients, with a total of 41 CDA. The study found good relief of preoperative symptoms (92%) and the ability to maintain operational readiness with a high rate of return to full unrestricted duty (95%) with an average follow-up of 6 months. There was a low rate of complications related to the anterior cervical approach (5%-8%), with no device- or implant-related complications.

Occult femoral neck fracture associated with vitamin D deficiency diagnosed by MRI: case report.

Hip fractures in the young are exceedingly rare and are usually seen in instances of high energy trauma or metabolically altered bone states. In this case report, we present an occult femoral neck fracture, diagnosed by magnetic resonance imaging, in an otherwise healthy, young, active duty male patient with an isolated vitamin D deficiency treated using cannulated percutaneous screws.

Synopsis of the 2020 US Department of Veterans Affairs/US Department of Defense Clinical Practice Guideline: The Non-Surgical Management of Hip and Knee Osteoarthritis.

In July 2020, the US Department of Veterans Affairs (VA) and US Department of Defense (DoD) approved a new joint clinical practice guideline for the non-surgical management of hip and knee osteoarthritis. This synopsis highlights some of the recommendations. In February 2019, the VA/DoD Evidence-Based Practice Work Group convened a joint VA/DoD guideline development effort that included clinical stakeholders and conformed to the National Academy of Medicine's tenets for trustworthy clinical practice guidelines. The guideline panel developed key questions, systematically searched (ie, Cochrane Database of Systematic Reviews, EMBASE, MEDLINE PreMEDLINE, PubMed, and the Agency for Healthcare Research and Quality website) and evaluated the literature, created a simple 1-page algorithm, and advanced 19 recommendations using the Grading of Recommendations Assessment, Development, and Evaluation system. This synopsis summarizes key recommendations in all 6 topics covered in the guideline. These topics are diagnosis, self-management, physical therapy, pharmacotherapy, orthobiologics, and complementary and integrative health.

Bilateral Fractures of Anatomic Medullary Locking Hip Arthroplasty Stems in a Single Patient: A Case Report.

INTRODUCTION: Stem fracture is a rare complication of total hip arthroplasty (THA) using fully porous-coated femoral stems. Bilateral fractures in a single patient have not been previously reported. CASE REPORT: A 48-year-old female underwent bilateral staged primary THA with fully porous-coated anatomic medullary locking femoral prostheses. She subsequently sustained stem fractures of her right and left prostheses in the 13thand 14thyears after their implantation, respectively. CONCLUSION: The bilateral nature of this rare complication in a single patient supports the notion that stem fracture results from a mismatch between the mechanical stresses encountered in vivo and the structural properties of small-diameter stems. Surgeons should be cognizant of this potential complication when evaluating patients at long-term follow-up with new-onset pain.

Low Revision Rates at 10 years for Metal on Metal Hip Implants in a Military Population.

INTRODUCTION: Prior to being largely abandoned due to unacceptably high failure rates and the adverse physiologic reactions to metal ions, metal-on-metal (MoM) total hip arthroplasty (THA) and hip resurfacing (HR) were in widespread use throughout the USA, and the potential benefit of decreased volumetric wear rates made it of particular interest to those who serve a young active population, such as military surgeons. The aim of our study was to determine the revision rate of metal on metal hip implants performed at our military institution and obtain current patient reported outcomes from this cohort. MATERIALS AND METHODS: We conducted a retrospective review of patients who underwent MoM total hip arthroplasty (THA) or hip resurfacing (HR) at our institution from 2006 to 2012. Revision status and component type were determined, and patients were contacted to obtain current HOOS JR scores. RESULTS: We identified 103 THAs in 88 patients and 38 HRs in 33 patients, with mean follow up of 10.2 years. Average age at time of surgery was 48 years, and 85% of the patients were male. The mean HOOS JR score in the THA and HR groups were 84.9 ± 17.6 and 75.8 ± 24.9, respectively (p = 0.38), and were not significantly lower in those who were revised. Two THA revisions occurred for metallosis and one for aseptic loosening of the femoral component. One HR revision occurred for breach of the anterior femoral neck, and one occurred for heterotopicossification. CONCLUSIONS: Revision rates of MoM THA and HR in this young, predominantly male population were 2.9% and 5.3%, respectively, and patients maintained generally good hip-specific outcomes.

Differential tuning of the electron transfer parameters in 1,3,5-triarylpyrazolines: a rational design approach for optimizing the contrast ratio of fluorescent probes.

A large class of cation-responsive fluorescent sensors utilizes a donor-spacer-acceptor (D-A) molecular framework that can modulate the fluorescence emission intensity through a fast photoinduced intramolecular electron transfer (PET) process. The emission enhancement upon binding of the analyte defines the contrast ratio of the probe, a key property that is particularly relevant in fluorescence microscopy imaging applications. Due to their unusual electronic structure, 1,3,5-triarylpyrazoline fluorophores allow for the differential tuning of the excited-state energy DeltaE(00) and the fluorophore acceptor potential E(A/A(-)), both of which are critical parameters that define the electron transfer (ET) thermodynamics and thus the contrast ratio. By systematically varying the number and attachment positions of fluoro substituents on the fluorophore pi-system, DeltaE(00) can be adjusted over a broad range (0.4 eV) without significantly altering the acceptor potential E(A/A(-)). Experimentally measured D-A coupling and reorganization energies were used to draw a potential map for identifying the optimal ET driving force that is expected to give a maximum fluorescence enhancement for a given change in donor potential upon binding of the analyte. The rational design strategy was tested by optimizing the fluorescence response of a pH-sensitive probe, thus yielding a maximum emission enhancement factor of 400 upon acidification. Furthermore, quantum chemical calculations were used to reproduce the experimental trends of reduction potentials, excited-state energies, and ET driving forces within the framework of linear free energy relationships (LFERs). Such LFERs should be suitable to semiempirically predict ET driving forces with an average unsigned error of 0.03 eV, consequently allowing for the computational prescreening of substituent combinations to best match the donor potential of a given cation receptor. Within the scaffold of the triarylpyrazoline platform, the outlined differential tuning of the electron transfer parameters should be applicable to a broad range of cation receptors for designing PET sensors with maximized contrast ratios.

Elimination of Preoperative Flexion Contracture as a Contraindication for Unicompartmental Knee Arthroplasty.

INTRODUCTION: Unicompartmental knee arthroplasty (UKA) is an effective alternative to total knee arthroplasty (TKA) for the management of unicondylar osteoarthritis. Historical contraindications limit patients' eligibility for UKA. However, recent reports have suggested that some contraindications may not be absolute. This study evaluates preoperative flexion contracture with regard to UKA. METHODS: This study was a retrospective review of 53 patients with preoperative flexion contracture between 11° and 20° who underwent fixed-bearing UKA and a matched cohort of 53 patients who underwent cruciate-retaining TKA. RESULTS: Preoperatively, the average flexion contracture was 13.8° in the UKA group and 14.1° in the TKA group (P = 0.42). Mean preoperative motion was greater in the patients treated with UKA (106°) than in those treated with TKA (97°; P < 0.001). Postoperatively, patients who underwent UKA had greater motion than patients who underwent TKA had (121° versus 113°; P < 0.01). Residual flexion contracture was greater in the UKA group (4.1°) than in the TKA group (2.1°; P = 0.02). The two groups demonstrated similar improvements in Knee Society clinical scores (P = 0.32). However, patients treated with UKA demonstrated higher Knee Society functional scores, compared with patients treated with TKA (86 versus 75; P = 0.03). DISCUSSION: Although residual flexion contracture was worse after UKA, this group had similar clinical improvement, greater postoperative motion, and greater function scores, compared with the matched TKA group. Preoperative flexion contracture >5° may not be an absolute contraindication to UKA. CONCLUSION: The contraindications to UKA regarding flexion contracture may not be as absolute as previously thought. Larger, prospective studies are needed to generalize these findings to a wider population.

Analysis of MDMA and its metabolites in urine and plasma following a neurotoxic dose of MDMA.

3,4-Methylenedioxymethamphetamine (MDMA), a commonly encountered drug of abuse, has been shown in a variety of studies to cause neurotoxic effects. Because MDMA itself is not neurotoxic, identifying the potential neurotoxic metabolite(s) was of significant importance. Evaluation of urine and plasma concentrations of MDMA and three of its main metabolites, 3,4-methylenedioxyamphetamine (MDA), 4-hydroxy-3-methoxyamphetamine (HMA), and 4-hydroxy-3-methoxymethamphetamine (HMMA), following administration of a neurotoxic dose (20 mg/kg) to male Dark Agouti rats was accomplished. Currently there are no data available describing urine and plasma concentrations of MDMA and these metabolites over a period of 7 days. The rats received a single 20 mg/kg i.p. dose of MDMA. Blood and urine samples were collected prior to administration and at 2, 4, 8, 12, 16, 20, 24, 48, 96, and 168 h following drug administration. Plasma and urine samples were extracted using solid-phase extraction, derivatized with N-methyl-bis(trifluoroacetamide), then analyzed using gas chromatography-mass spectrometry. Urine samples showed peak concentrations of MDMA at 4 h, MDA at 8 h, HMMA at 12 h, and HMA at 16 h post dose. MDMA and its metabolites were detectable (limit of detection 25 ng/mL) in the urine for up to 168 h post dose. Plasma samples showed mean peak concentrations of MDMA and MDA at 2 h post dose and HMMA at 4 h. Although the highest mean concentration of HMA was seen at 24 h post dose, variability between sample results for this time point was significant. No detectable levels of MDMA, MDA, HMA, and HMMA (LOD 10 ng/mL) were found in plasma at 96 and 168 h post dose.

Biomechanical Stability of a Stand-Alone Interbody Spacer in Two-Level and Hybrid Cervical Fusion Constructs.

STUDY DESIGN: In vitro human cadaveric biomechanical analysis. OBJECTIVE: To evaluate the segmental stability of a stand-alone spacer (SAS) device compared with the traditional anterior cervical plate (ACP) construct in the setting of a 2-level cervical fusion construct or as a hybrid construct adjacent to a previous 1-level ACP construct. METHODS: Twelve human cadaveric cervical spines (C2-T1) were nondestructively tested with a custom 6-degree-of-freedom spine simulator under axial rotation (AR), flexion-extension (FE), and lateral bending (LB) at 1.5 N m loads. After intact analysis, each specimen underwent instrumentation and testing in the following 3 configurations, with each specimen randomized to the order of construct: (A) C5-7 SAS; (B) C5-6 ACP, and C6-7 SAS (hybrid); (C) C5-7 ACP. Full range of motion (ROM) data at C5-C7 was obtained and analyzed by each loading modality utilizing mean comparisons with repeated measures analysis of variance with Sidak correction for multiple comparisons. RESULTS: Compared with the intact specimen, all tested constructs had significantly increased segmental stability at C5-C7 in AR and FE ROM, with no difference in LB ROM. At C5-C6, all test constructs again had increased segmental stability in FE ROM compared with intact (10.9° ± 4.4° Intact vs SAS 6.6° ± 3.2°, P < .001; vs.Hybrid 2.9° ± 2.0°, P = .005; vs ACP 2.1° ± 1.4°, P < .001), but had no difference in AR and LB ROM. Analysis of C6-C7 ROM demonstrated all test groups had significantly greater segmental stability in FE ROM compared with intact (9.6° ± 2.7° Intact vs SAS 5.0° ± 3.0°, P = .018; vs Hybrid 5.0° ± 2.7°, P = .018; vs ACP 4.4° ± 5.2°, P = .005). Only the hybrid and 2-level ACP constructs had increased stability at C6-C7 in AR ROM compared with intact, with no difference for all test groups in LB ROM. Comparison between test constructs demonstrated no difference in C5-C7 and C6-C7 segmental stability in all planes of motion. However, at C5-C6 comparison between test constructs found the 2-level SAS had significantly less segmental stability compared to the hybrid (6.6° ± 3.2° vs 2.9° ± 2.0°, P = .025) and ACP (6.6° ± 3.2° vs 2.1° ± 1.4°, P = .004). CONCLUSIONS: Our study found the currently tested SAS device may be a reasonable option as part of a 2-level hybrid construct, when used below an adjacent 1-level ACP, but should be used with careful consideration as a 2-level SAS construct. Consequences of decreased segmental stability in FE are unknown; however, optimal immediate fixation stability is an important surgical principle to avoid loss of fixation, segmental kyphosis, interbody graft subsidence, and pseudarthrosis.

Pelvic Floor Reconstruction Utilizing a Residual Hamstring Rotational Flap Following Traumatically Induced Subtotal Hemipelvectomy in a Combat Blast Casualty: A Case Report.

OBJECTIVE: There are several options for soft tissue coverage following external hemipelvectomy; however, in cases of war-related blast trauma, standard flaps are not always available as a result of the extensive soft tissue damage. METHODS: We detail a novel closure technique following a subtotal hemipelvectomy with exposed abdominal viscera using a residual hamstring myofascial cutaneous flap. RESULTS: This flap allowed for fascial tissue to fill the pelvic defect and provided excellent soft tissue coverage for future prosthetic wear. DISCUSSION: In the current literature, there is limited information regarding surgical options for soft tissue coverage following traumatic hip disarticulation. Most cases result from malignancies or severe infection, where tissue distal to the lesion is viable and provides adequate coverage. This case report used a novel technique, provided excellent soft tissue coverage with no wound healing complications, allowed for excellent prosthetic fitting, and the patient's ability to ambulate without assistance.

Persistent axial neck pain after cervical disc arthroplasty: a radiographic analysis.

BACKGROUND CONTEXT: There is very little literature examining optimal radiographic parameters for placement of cervical disc arthroplasty (CDA), nor is there substantial evidence evaluating the relationship between persistent postoperative neck pain and radiographic outcomes. PURPOSE: We set out to perform a single-center evaluation of the radiographic outcomes, including associated complications, of CDA. DESIGN: This is a retrospective review. PATIENT SAMPLE: Two hundred eighty-five consecutive patients undergoing CDA were included in the review. OUTCOME MEASURES: The outcome measures were radiological parameters (preoperative facet arthrosis, disc height, CDA placement in sagittal and coronal planes, heterotopic ossification [HO] formation, etc.) and patient outcomes (persistent pain, recurrent pain, new-onset pain, etc.). METHODS: We performed a retrospective review of all patients from a single military tertiary medical center from August 2008 to August 2012 undergoing CDA. Preoperative, immediate postoperative, and final follow-up films were evaluated. The clinical outcomes and complications associated with the procedure were also examined. RESULTS: The average radiographic follow-up was 13.5 months and the rate of persistent axial neck pain was 17.2%. For patients with persistent neck pain, the rate of HO formation per level studied was 22.6%, whereas the rate was significantly lower for patients without neck pain (11.7%, p=.03). There was no significant association between the severity of HO and the presence of neck pain. Patients with a preoperative diagnosis of cervicalgia, compared to those without cervicalgia, were significantly more likely to experience continued neck pain postoperatively (28.6% vs. 13.1%, p=.01). There were no differences in preoperative facet arthrosis, pre- or postoperative disc height, segmental range of motion, or placement of the device relative to the posterior edge of the vertebral body.However, patients with implants more centered between the uncovertebral joints were more likely to experience posterior neck pain (p=.03). CONCLUSIONS: We found that posterior axial neck pain is relatively frequent after CDA, and patients with persistent neck pain were significantly more likely to have preoperative cervicalgia and develop HO postoperatively. We also found that patients with implants that were placed off-centered were less likely to also complain of neck pain, although the reasons for this finding remain unclear.