Publications by authors named "Florian Wanivenhaus"

29 Publications

  • Page 1 of 1

Patient-specific statistical shape modeling for optimal spinal sagittal alignment in lumbar spinal fusion.

Eur Spine J 2021 May 2. Epub 2021 May 2.

Department of Orthopedic Surgery, Balgrist University Hospital, University of Zurich, Forchstrasse 340, 8008, Zurich, Switzerland.

Purpose: The present study compared patients developing ASD after L4/5 spinal fusion with a control group using a patient-specific statistical shape model (SSM) to find alignment-differences between the groups.

Methods: This study included patients who had undergone spinal fusion at L4/5 and either remained asymptomatic (control group; n = 25, follow-up of > 4 years) or required revision surgery for epifusional ASD (n = 22). Landmarks on preoperative and postoperative lateral radiographs were annotated, and the optimal spinal sagittal alignment was calculated for each patient. The two-dimensional distance from the SSM-calculated optimum to the actual positions before and after fusion surgery was compared.

Results: Postoperatively, the additive mean distance from the SSM-calculated optimum was 86.8 mm in the ASD group and 67.7 mm in the control group (p = 0.119). Greater differences were observed between the groups with a larger distance to the ideal in patients with ASD at more cranial levels. Significant difference between the groups was seen postoperatively in the vertical distance of the operated segment L4. The patients with ASD (5.69 ± 3.0 mm) had a significant greater distance from the SSM as the control group (3.58 ± 3.5 mm, p = 0.034).

Conclusion: Patients with ASD requiring revision after lumbar spinal fusion have greater differences from the optimal spinal sagittal alignment as an asymptomatic control group calculated by patient-specific statistical shape modeling. Further research might help to understand the value of SSM, in conjunction with already established indexes, for preoperative planning with the aim of reducing the risk of ASD.

Level Of Evidence I: Diagnostic: individual cross-sectional studies with consistently applied reference standard and blinding.
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http://dx.doi.org/10.1007/s00586-021-06852-xDOI Listing
May 2021

Augmented Reality Navigated Sacral-Alar-Iliac Screw Insertion.

Int J Spine Surg 2021 Feb 18;15(1):161-168. Epub 2021 Feb 18.

Department of Orthopedics, University Hospital Balgrist, University of Zürich, Zürich, Switzerland.

Background: Sacral-alar-iliac (SAI) screws are increasingly used for lumbo-pelvic fixation procedures. Insertion of SAI screws is technically challenging, and surgeons often rely on costly and time-consuming navigation systems. We investigated the accuracy and precision of an augmented reality (AR)-based and commercially available head-mounted device requiring minimal infrastructure.

Methods: A pelvic sawbone model served to drill pilot holes of 80 SAI screw trajectories by 2 surgeons, randomly either freehand (FH) without any kind of navigation or with AR navigation. The number of primary pilot hole perforations, simulated screw perforation, minimal axis/outer cortical wall distance, true sagittal cranio-caudal inclination angle (tSCCIA), true axial medio-lateral angle, and maximal screw length (MSL) were measured and compared to predefined optimal values.

Results: In total, 1/40 (2.5%) of AR-navigated screw hole trajectories showed a perforation before passing the inferior gluteal line compared to 24/40 (60%) of FH screw hole trajectories ( < .05). The differences between FH- and AR-guided holes compared to optimal values were significant for tSCCIA with -10.8° ± 11.77° and MSL -65.29 ± 15 mm vs 55.04 ± 6.76 mm ( = .001).

Conclusions: In this study, the additional anatomical information provided by the AR headset and the superimposed operative plan improved the precision of drilling pilot holes for SAI screws in a laboratory setting compared to the conventional FH technique. Further technical development and validation studies are currently being performed to investigate potential clinical benefits of the AR-based navigation approach described here.

Level Of Evidence: 4.
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http://dx.doi.org/10.14444/8021DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7931709PMC
February 2021

High-resolution in vivo MR imaging of intraspinal cervical nerve rootlets at 3 and 7 Tesla.

Eur Radiol 2021 Jan 6. Epub 2021 Jan 6.

Swiss Center for Musculoskeletal Imaging (SCMI), Balgrist Campus AG, Zurich, Switzerland.

Objectives: No routine imaging technology allows reliable visualization of nerve rootlets inside the spinal canal with positive contrast. The stronger MR signal at 7 T, with optimized protocols, may offer a solution. The purpose was to evaluate the potential of 3D Dual-Echo Steady-State (DESS) MR imaging of the cervical spine at 3 and 7 T in assessing the micro-anatomy of the nerve rootlets.

Materials/methods: This prospective study was approved by the local ethics committee. Twenty-one patients, clinically referred to cervical-spine MRI, underwent additional MR exams at 3 T and 7 T, each of which consisted of a single 3D-DESS series with equal acquisition times. Artifacts, visualization quality, and number of identified rootlets (C2 to C8) were rated by two musculoskeletal radiologists. Results were compared by Wilcoxon tests. Interobserver reliability was assessed using weighted κ statistics and intraclass correlation coefficient (ICC).

Results: Intraspinal rootlets could successfully be visualized at both field strengths. Rating differences for artifacts and quality of rootlet depiction were not significant for the two field strengths. The mean number of identified rootlets was larger for 7-T than for 3-T MR for every assessed nerve; however, this difference was not statistically significant using the Bonferroni correction (p values ranging from 0.002 to 0.53). Interobserver agreement was substantial to almost perfect (weighted κ values of 0.69 and 0.82). The ICC for the number of identified rootlets was 0.80.

Conclusion: Non-invasive 3D-DESS MR-imaging at 3 and 7 T has the potential to provide precise assessments of the micro-anatomy of intraspinal cervical nerve roots.

Key Points: • Cervical rootlets can be successfully visualized with positive contrast using 3D-DESS MR-imaging. • 3D-DESS MR-imaging at 3 and 7 T provides precise assessments of the micro-anatomy of cervical nerves. • The mean number of identified cervical rootlets using 3D-DESS was larger for 7 T than for 3 T MR; however, this difference was not statistically significant.
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http://dx.doi.org/10.1007/s00330-020-07557-3DOI Listing
January 2021

Ultrasound-guided interventions with augmented reality in situ visualisation: a proof-of-mechanism phantom study.

Eur Radiol Exp 2020 02 4;4(1). Epub 2020 Feb 4.

Department of Orthopaedics, Balgrist University Hospital, University of Zurich, Forchstrasse 340, 8008, Zurich, Switzerland.

Background: Ultrasound (US) images are currently displayed on monitors, and their understanding needs good orientation skills. Direct overlay of US images onto the according anatomy is possible with augmented reality (AR) technologies. Our purpose was to explore the performance of US-guided needle placement with and without AR in situ US viewing.

Methods: Three untrained operators and two experienced radiologists performed 200 US-guided punctures: 100 with and 100 without AR in situ US. The punctures were performed in two different phantoms, a leg phantom with soft tissue lesions and a vessel phantom. Time to puncture and number of needle passes were recorded for each puncture. Data are reported as median [range] according to their non-normal distribution.

Results: AR in situ US resulted in reduced time (median [range], 13 s [3-101] versus 14 s [3-220]) and number of needle passes (median [range], 1 [1-4] versus 1 [1-8]) compared to the conventional technique. The initial gap in performance of untrained versus experienced operators with the conventional US (time, 21.5 s [3-220] versus 10.5 s [3-94] and needle passes 1 [1-8] versus 1 [1, 2]) was reduced to 12.5 s [3-101] versus 13 s [3-100] and 1 [1-4] versus 1 [1-4] when using AR in situ US, respectively.

Conclusion: AR in situ US could be a potential breakthrough in US applications by simplifying operator's spatial orientation and reducing experience-based differences in performance of US-guided interventions. Further studies are needed to confirm these preliminary phantom results.
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http://dx.doi.org/10.1186/s41747-019-0129-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7000569PMC
February 2020

Augmented reality-assisted rod bending in spinal surgery.

Spine J 2019 10;19(10):1687-1689

Department of Orthopaedics, University of Zurich, Balgrist University Hospital, Forchstrasse 340, 8008 Zürich, Switzerland.

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http://dx.doi.org/10.1016/j.spinee.2019.06.019DOI Listing
October 2019

No benefit of early versus late ambulation after incidental durotomy in lumbar spine surgery: a randomized controlled trial.

Eur Spine J 2020 01 24;29(1):141-146. Epub 2019 Sep 24.

University Spine Center Zurich, Balgrist University Hospital, University of Zurich, Forchstrasse 340, 8008, Zurich, Switzerland.

Purpose: Incidental durotomy (ID) is a complication occurring in 4-17% of decompressive spinal surgeries. Persisting CSF leakage can occur even after ID repair and requires revision surgery. Prolonged flat bed rest (BR) to reduce the incidence of persisting CSF leakage is frequently applied but highly debated. A randomized controlled trial comparing prolonged BR versus early ambulation after ID repair is lacking. The aim of this study was to investigate the incidence of revision surgery as a result of persistent cerebro-spinal fluid (CSF) leakage and medical complications after immediate or late post-operative ambulation following ID during decompressive spinal surgery.

Methods: Ninety-four of 1429 consecutive cases undergoing lumbar spine surgery (6.58%) were complicated by an ID. Sixty patients (mean age of 64 ± 13.28 years) were randomized to either early post-operative ambulation (EA, n = 30) or flat BR for 48 h (BR, n = 30). The incidence of CSF leakage resulting in revision surgery, medical complications and duration of hospitalization were compared between groups.

Results: Two patients in the BR group and two patients in the EA group underwent revision surgery as a result of persisting CSF leakage. Four patients in the BR group experienced medical complications associated with prolonged immobilization. The duration of hospitalization was 7.25 ± 3.0 days in the BR group versus 6.56 ± 2.64 days in the EA group, p = 0.413.

Conclusion: The results of this study indicate no benefit of prolonged BR after an adequately repaired ID in lumbar spine surgery.

Level Of Evidence: Level 1b (individual randomized controlled trial). These slides can be retrieved under Electronic Supplementary Material.
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http://dx.doi.org/10.1007/s00586-019-06144-5DOI Listing
January 2020

Time course of costamere-related alterations in focal adhesion signaling and composition of rat soleus muscle after achilles tenotomy.

Data Brief 2019 Aug 10;25:103999. Epub 2019 Jul 10.

Laboratory for Muscle Plasticity, Department of Orthopedics, University of Zurich, Balgrist Campus, Zurich, Switzerland.

Sarcolemma-based focal adhesions (costameres) are a central hub for the cytoskeletal anchoring of myofibrils and mechano-regulated signaling. Here we report the time course of alterations in focal adhesion-associated signaling and fiber composition in rat soleus muscle after Achilles tenotomy. The report includes data from tenotomized muscles and contralateral mock controls to expose whether muscle degeneration after tenotomy is due to the transection of the Achilles tendon, or circumjacent surgical manipulations of the tendon. With respect to the interpretation of the data regarding mechanistic implications of costamere-associated processes for surgical repair of the detached muscle-tendon complex the reader is referred to the accompanying research article 'Focal adhesion kinase coordinates costamere-related JNK signaling with muscle fiber transformation after Achilles tenotomy and tendon reconstruction' Ferrié et al., 2019.
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http://dx.doi.org/10.1016/j.dib.2019.103999DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6706776PMC
August 2019

Same-Day Surgery Does Not Increase the Manipulation Under Anesthesia and Reoperation Rates for Stiffness Following Bilateral Total Knee Arthroplasty.

J Arthroplasty 2019 Nov 14;34(11):2646-2651. Epub 2019 Jun 14.

Division of Adult Reconstruction and Joint Replacement, Department of Orthopaedic Surgery, Hospital for Special Surgery, Weill Medical College of Cornell University, New York, NY.

Background: There is a paucity of data on the incidence of stiffness and need for subsequent manipulation under anesthesia (MUA) and reoperation following same-day bilateral total knee arthroplasty (BTKA). We compared the rates of at least 1 MUA, bilateral knee involvement, single and multiple MUA rates, and stiffness-related reoperation rates between patients undergoing same-day, same-admission staged, and staged within 1 year BTKA in a tertiary institution.

Methods: We analyzed institutional data for 3175 same-day (group A), 153 same-admission staged (group B), and 1226 staged within 1 year BTKA patients (group C) from 1998 to 2009. Several variables, including patient demographics, comorbidity profile, Charlson-Deyo index, and range of motion at different time points, were tabulated. Follow-up was minimum 1 year after first MUA. Univariate analyses were performed using the Wilcoxon rank-sum or Kruskal-Wallis test, and Fisher exact or the chi-square test for continuous and categorical variables, respectively. The Cochran-Armitage trend test was used to check the bilateral knee involvement rate across groups.

Results: Overall, 2.2% (98/4554) of BTKA patients required MUA. The rate of at least 1 MUA was similar across groups but the percentage of bilateral knee involvement was higher in group A. The single MUA rate was comparable among groups. Both no revision and revision reoperation rates were similar among the manipulated groups.

Conclusion: Same-day BTKA was not associated with increased incidence of single or multiple MUA and stiffness-related reoperation rates. These findings may facilitate preoperative counseling in patients with symptomatic bilateral knee disease, eligible for same-day BTKA.
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http://dx.doi.org/10.1016/j.arth.2019.06.017DOI Listing
November 2019

Predictors for reoperation after lower limb amputation in patients with peripheral arterial disease.

Vasa 2019 Aug 7;48(5):419-424. Epub 2019 May 7.

Department of Orthopaedic Surgery, Balgrist University Hospital, Zurich, Switzerland.

Major amputations in patients with peripheral arterial disease (PAD) carry a high risk for complications, including revision of the amputation, sometimes to a higher level. Determining a safe level for amputation with good wound healing potential depends largely on vascular measurements. This study evaluated potential predictive factors for revision of major lower extremity amputations in patients with PAD. A retrospective chart review of all major lower extremity amputations at our institution was conducted. Amputations due to trauma or tumor and below-ankle amputations were excluded. Patient demographics, level/type of amputation, level/time of revision, comorbidities and risk factors were extracted. 180 patients with PAD, mean age 66.48 (range: 31-93) years, 125 (69.4%) male were included. Most (154/180, 86.6%) underwent below-knee amputation. 71 (39.4%) patients had coronary arterial disease, 104 (57.8%) had diabetes. More than half of patients, (93/138; 51.7%) had undergone previous balloon angioplasty. 44 (30%) patients required revision surgery: 42/180 (23.3%) were revised at the same level, and in 12/180 (6.7%) a more proximal amputation was necessary. PAD stage was not associated with the level of reamputation (p = 0.4369). Significantly more patients who had previous balloon angioplasty required revision surgery (66.7% versus 45.2%, p = 0.009). 67 (37.2%) patients underwent preoperative TcPO2 measurement: 40/67 (59.7%) had TcPO2 ≥ 40 mmHg; 4/67 (6%) had TcPO2 < 10 mmHG. Three patients with TcPO2 ≥ 40 mmHg, one with 30 mmHg ≤ TcPO2 ≤ 40 mmHg and one with 10 mmHg ≤ TcPO2 ≤ 20 mmHg required re-amputation to a more proximal level. TcPO2 measurements are useful for determining level of lower limb amputation and predicting wound healing problems when an amputation level with TcPO2 < 40 mmHg is chosen. In transtibial amputations, TcPO2 ≥ 40 mmHg does not safely predict wound healing.
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http://dx.doi.org/10.1024/0301-1526/a000796DOI Listing
August 2019

Focal adhesion kinase coordinates costamere-related JNK signaling with muscle fiber transformation after Achilles tenotomy and tendon reconstruction.

Exp Mol Pathol 2019 06 15;108:42-56. Epub 2019 Mar 15.

Laboratory for Muscle Plasticity, Department of Orthopedics, University of Zurich, Balgrist Campus, Zurich, Switzerland. Electronic address:

Achilles tendon rupture necessitates rapid tendon reattachment to reinstate plantar flexion before affected muscles deteriorate through muscle fiber atrophy and transformation. The implicated process may involve alterations in sarcolemmal sites of myofibril attachment (costameres), which control myofibrillogenesis via a mechano-regulated mechanism through integrin-associated focal adhesion kinase (FAK). We assessed the contribution of FAK to alterations in fiber type composition and expression of costamere-associated structural proteins, the phosphorylation status of Y397-FAK and downstream mTOR/JNK-P70S6K hypertrophy signaling in rat soleus muscle after Achilles tenotomy and tendon repair. Achilles tenotomy induced a profound deterioration of muscle composition 14 days, but not 4 days, following tendon release, comprising specifically increased area percentages of fast type fibers, fibers with internal nuclei, and connective tissue. Concomitantly, expression of costameric proteins FAK and meta-vinculin, and phosphorylation of T421/S424-P70S6K and T183/Y185-JNK was elevated, all of which was mitigated by tendon reattachment immediately after release. Overexpression of FAK in soleus muscle fibers and reattachment corrected the expression of meta- and gamma-vinculin isoforms to the lower levels in mock controls while further enhancing T183/Y185-JNK phosphorylation and levels of FAK C-terminus-related inhibitory proteins. Co-overexpression of the FAK inhibitor, FRNK, lowered FAK-overexpression driven Y397-FAK phosphorylation and T183/Y185-JNK phosphorylation. FAK levels correlated to molecular and cellular hallmarks of fiber degeneration. The findings demarcate the window between 4 and 14 days after tenotomy as costamere-dependent muscle transformation process, and expose that FAK overexpression prevents molecular aspects of the pathology which within the study limitations does not result in the mitigation of muscle fiber degeneration.250 words.
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http://dx.doi.org/10.1016/j.yexmp.2019.03.006DOI Listing
June 2019

Does blood transfusion type affect complication and length of stay following same-day bilateral total knee arthroplasty?

J Orthop 2018 Jun 21;15(2):308-312. Epub 2018 Feb 21.

Department of Orthopaedic Surgery, Adult Reconstruction and Joint Replacement Division, Hospital for Special Surgery, 535 East 70th St, New York, NY, 10021, USA.

Same-day Bilateral Total Knee Arthroplasty (BTKA) safety is still controversial. The aim of this study was to examine the association of blood transfusion type (pure autologous, pure allogeneic, and combined) with complication and prolonged length of stay (PLOS) following same-day BTKA. 649 consecutive patients were retrospectively identified over a two-year period. Pure allogeneic transfusions were associated with increased odds of minor complication when compared to patients who had pure autologous transfusions. No association was found between blood transfusion type and major complication or PLOS. Our results suggest that blood transfusion type may be influential in minor complication after BTKA.
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http://dx.doi.org/10.1016/j.jor.2018.02.014DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5856672PMC
June 2018

Clinical and Radiologic Outcomes of Metatarsophalangeal Hemiarthroplasty: A Review of 12 Consecutive Cases.

Orthopedics 2018 Jan 21;41(1):e64-e69. Epub 2017 Nov 21.

This study examined function, pain, satisfaction, and radiologic outcomes among patients treated with first metatarsophalangeal hemiarthroplasty. Patients were invited to participate in an outcome study conducted with questionnaires on subjective and objective outcomes and clinical and radiographic follow-up. A total of 12 patients (12 feet; mean patient age, 58.8±12.3 years) agreed to participate. Mean follow-up was 22.3±19.8 months. Of these patients, 7 were satisfied with the postoperative result. The mean visual analog scale pain score decreased significantly from 7.0±2.3 preoperatively to 3.5±3.3 postoperatively (P=.024). Mean passive range of motion of the first metatarsophalangeal joint was 32°±10° preoperatively, 93°±18° intraoperatively after implantation of the prosthesis and closure of the joint capsule, and 38°±19° at final follow-up (P=.26). Mean American Orthopaedic Foot and Ankle Society forefoot score increased significantly from 47.3±14.7 preoperatively to 71.8±15.2 at last follow-up (P=.033). During the follow-up period, 6 patients underwent additional procedures: 5 therapeutic joint infiltrations and 1 arthrodesis. No patients had radiologic loosening of the implant at final follow-up. Osseous dysplastic changes at the base of the proximal phalanx were noted among 6 of 11 patients (12 total cases) at final follow-up. Although first metatarsophalangeal hemiarthroplasty provided significant pain reduction at mean follow-up of 22.3 months, range of motion of the first metatarsophalangeal joint was not restored to anticipated levels and there were high rates of patient dissatisfaction and secondary interventions. [Orthopedics. 2018; 41(1):e64-e69.].
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http://dx.doi.org/10.3928/01477447-20171114-03DOI Listing
January 2018

Nonsurgical Treatment of Osteomyelitis of the Hallux Sesamoids: A Case Series and Literature Review.

J Foot Ankle Surg 2017 May - Jun;56(3):666-669

Attending Surgeon, Department of Orthopedics, Balgrist University Hospital, Zürich, Switzerland.

The aim of the present study was to determine the effectiveness of nonsurgical treatment for osteomyelitis of the hallucal sesamoids. Osteomyelitis of the hallucal sesamoids in young and healthy patients is rare and might originate from hematogenous spread or after a puncture wound. In diabetic patients with peripheral neuropathy, it often results from direct contiguous seeding from adjacent ulceration. The superiority of surgical versus nonsurgical therapy is still debated. In our institution, all patients presenting with osteomyelitis of the hallucal sesamoids are first treated nonsurgically but eventually usually require a surgical procedure. We reviewed 18 patients with a clinical and radiologic diagnosis of osteomyelitis of the hallucal sesamoids treated in our institution during a 13-year period (from January 2000 to December 2012). The inclusion criteria were a signal alteration on magnetic resonance imaging or bone lesions on computed tomography or conventional radiographs, combined with a deep ulcer with a positive probe-to-bone test. Nonsurgical therapy consisted of frequent wound treatment, immobilization, offloading in a cast or other orthotic device, and oral antibiotics. Of the 18 patients, 11 had diabetes, 16 had peripheral neuropathy, 11 had peripheral arterial disease, and 5 had immunosuppression. After a period of nonsurgical therapy ranging from 4 weeks to 9 months, 15 of 18 patients required surgical excision, internal resection, or amputation. In this patient population, we no longer consider nonsurgical therapy a viable option. Patients should be advised, before starting nonsurgical treatment, that the therapy will be long and demanding and very often results in a surgical procedure.
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http://dx.doi.org/10.1053/j.jfas.2017.01.025DOI Listing
November 2017

Conventional Radiographs and Magnetic Resonance Imaging for the Analysis of Trochlear Dysplasia: The Influence of Selected Levels on Magnetic Resonance Imaging.

Am J Sports Med 2017 Apr 8;45(5):1059-1065. Epub 2017 Feb 8.

Department of Orthopaedics, Balgrist University Hospital, University of Zurich, Zurich, Switzerland.

Background: Trochlear dysplasia is one of the most important risk factors for recurrent patellar instability. It is defined on true lateral conventional radiographs (CR) and axial magnetic resonance imaging (MRI). The type of trochlear dysplasia is decisive for surgical treatment; however, low agreement between CR and MRI has been reported.

Purpose: To compare the Dejour classification of trochlear dysplasia on CR and axial MRI using differing levels defined in the literature.

Study Design: Cohort study (diagnosis); Level of evidence, 2.

Methods: The 4-type classification of trochlear dysplasia by Dejour was used to analyze 228 knees with recurrent patellar dislocations on true lateral CR and axial MRI. The 2-type modification of the Dejour classification was also similarly analyzed. Measurements on axial MRI were performed at 3 different levels: MR1, the most proximal level where the intercondylar notch forms a "Roman arch"; MR2, 3 cm above the joint line; and MR3, the midpatellar height.

Results: MR1 was measured at a mean distance of 29 ± 3.5 mm and MR3 at a mean of 38 ± 5.8 mm above the joint line. MR1 and MR2 were always measured on the cartilaginous trochlea, whereas 52% of MR3 was found more proximally. Overall agreement was fair between CR and MR1/MR2 (31.1%/25.4%, respectively) and highest for MR3 (45.2%; P < .01). The highest agreement (81.8%) was found for MR3 with the 2-type trochlear dysplasia classification (low-grade trochlear dysplasia: type A vs high-grade trochlear dysplasia: types B, C, and D) and lower for MR1 (67.5%) and MR2 (62.0%).

Conclusion: Trochlear dysplasia measured on CR and MRI shows only fair agreement, especially when the supratrochlear region of the distal femur is not analyzed on axial MRI. MRI analysis that considers the cartilaginous trochlea only tends to underestimate the severity of dysplasia according to Dejour. For a more precise evaluation of trochlear dysplasia, the entire distal femur should be analyzed on axial MRI.
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http://dx.doi.org/10.1177/0363546516685054DOI Listing
April 2017

Quality of Early Union After First Metatarsophalangeal Joint Arthrodesis.

J Foot Ankle Surg 2017 Jan - Feb;56(1):50-53. Epub 2016 Nov 17.

Surgeon, Department of Orthopaedics, Balgrist University Hospital, University of Zurich, Zürich, Switzerland.

The aim of the present retrospective cohort study was to assess the quality of union and the clinical outcomes in patients who had undergone first metatarsophalangeal joint (MTPJ) fusion using a dorsal plate and plantar lag screw. From March 2011 to December 2012, the clinical and radiographic data of 39 patients (41 feet) who had undergone first MTPJ fusion using a compressive locking plate were retrospectively reviewed. All patients had undergone postoperative computed tomography at 6 weeks postoperatively to assess union. The average metatarsophalangeal angles improved from 23° ± 16° preoperatively to 14° ± 5° postoperatively. The dorsiflexion of the hallux at the preoperative assessment averaged 17° ± 11° and 23° ± 5° postoperatively. At 6 weeks postoperatively, the computed tomography scans demonstrated 3 complete fusions (7.3 %) and 38 partial unions (92.7%). Also at 6 weeks, the mean ± standard deviation joint bridging was 54% ± 14.6%. The forefoot American Orthopaedic Foot and Ankle Society scale score had improved significantly from 50 ± 13 preoperatively to 80 ± 7 at >1 year of follow-up (p = .001). Hardware removal was performed in 8 cases because of pain in 7 and infection in 1. Revision arthrodesis was required in 2 cases because of nonunion. At 6 weeks postoperatively, partial bony joint bridging could be observed in most cases after arthrodesis of the first MTPJ with the dorsal fusion plate.
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http://dx.doi.org/10.1053/j.jfas.2016.09.001DOI Listing
August 2017

Reliability of postoperative MR imaging in the determination of level and side of lumbar spinal decompression surgery.

Acta Radiol 2017 May 20;58(5):581-585. Epub 2016 Aug 20.

3 Spine Division, Department of Orthopaedics, Balgrist University Hospital, University of Zurich, Switzerland.

Background Magnetic resonance imaging (MRI) is the diagnostic modality of choice in defining soft tissue compromise of the spinal canal. Purpose To evaluate the reliability of postoperative MRI in the determination of level and side of lumbar spinal decompression surgery, investigated by two reviewers, in different levels of training and specialization. Material and Methods Postoperative MR images of 86 patients who underwent spinal decompression (single level, n = 70; multilevel, n = 16; revision decompression, n = 9) were reviewed independently by an experienced musculoskeletal radiologist and a fourth-year orthopedic surgery resident. The level (single or multiple) and side of previous surgical decompression were determined and compared to the surgical notes. We examined factors that may have influenced the reliability, including demographics, type of surgical decompression, use of a drain, and time interval from surgery to MRI. Results Significantly fewer levels were correctly determined by the resident (77/86 cases, 89.5%) compared with the radiologist (84/86 cases, 97.7%) ( P = 0.014). The resident interpreted significantly more MR images incorrectly in cases where a drain was used (n = 8; P < 0.001). Re-decompression cases were interpreted incorrectly significantly more often by both the radiologist (n = 2, P = 0.032) and the resident (n = 4, P = 0.014). Conclusion Determination of the level and side operated on in previous lumbar spinal decompression surgery on MRI has a high reliability, especially when performed by a musculoskeletal radiologist. However, this reliability is decreased in cases involving surgical drainage and same-level revision surgery.
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http://dx.doi.org/10.1177/0284185116661881DOI Listing
May 2017

Novel Protocol for Knee Mobilization Under Femoral and Sciatic Nerve Blocks for Postoperative Knee Stiffness.

Orthopedics 2016 Jul 27;39(4):e708-14. Epub 2016 Apr 27.

The purpose of this study was to evaluate the effectiveness of intermittent femoral and sciatic nerve blocks combined with an in-house physiotherapy protocol for treating postoperative knee stiffness. Sixty-eight patients with postoperative knee stiffness were evaluated for passive knee flexion and extension at different time points, beginning preoperatively and continuing throughout a median 10-month follow-up after mobilization intervention. Sciatic and femoral nerve catheters were activated 1 hour prior to each physiotherapy session, which was performed twice per day and supported by a continuous passive range of motion machine. Median time from admission to catheter removal was 4 days (range, 1-8 days). Mean hospital length of stay was 7 days (range, 2-19 days). Overall mean flexion increased significantly from pretreatment (74°) to discharge (109°; P<.01). There was no significant difference in mean flexion at 6-week follow-up compared with that at discharge (108°; P=.764), but there was a significant increase in flexion at final follow-up (120°; P=.002). Overall mean knee extension lag decreased significantly from pretreatment (5°) to discharge (0.4°; P=.001). There was no significant increase in mean extension lag from discharge to final follow-up (1°; P=.2). Overall, 11 patients underwent revision surgery for persistent stiffness. This novel protocol for continuous knee mobilization under perineural blocks is a valuable alternative to knee manipulation under anesthesia for this select group of procedures. The 2 techniques produced a similar early range of motion gain, but the reported protocol resulted in less range of motion loss at follow-up and fewer possible complications. [Orthopedics. 2016; 39(4):e708-e714.].
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http://dx.doi.org/10.3928/01477447-20160419-07DOI Listing
July 2016

Revision Rate and Risk Factors After Lower Extremity Amputation in Diabetic or Dysvascular Patients.

Orthopedics 2016 Jan-Feb;39(1):e149-54. Epub 2015 Dec 30.

This article reports the revision rate and possible risk factors for lower extremity amputations in patients with diabetes mellitus or peripheral arterial disease (PAD). Data were collected from 421 patients with diabetes mellitus or PAD who underwent amputations of the lower extremity at the authors' institution from 2002 to 2012. There was a 25.2% overall revision rate. Mean time from amputation to revision was 244 days (range, 2-2590 days). Patients with diabetes mellitus had a significantly higher rate of revision to a more proximal level compared with patients without diabetes mellitus (type 1: odds ratio [OR]=3.73; 95% confidence interval [CI], 1.21-11.52; P=.022; and type 2: OR=2.3; 95% CI, 1.07-4.95; P=.033). A significant increase in revision rates was observed from Fontaine stage 0 to IV (stage 0: 17.9%; stage IV, 34.7%; P=.03). Risk factors for revision were diabetic nephropathy (OR=2.26; 95% CI, 1.4-3.63; P=.001) and polyneuropathy (OR=1.68; 95% CI, 1.03-2.73; P=.037). Patients who underwent revision amputation had a significantly younger mean age than patients who did not undergo revision amputation (65.23 years [range, 40-92 years] vs 68.52 years [range, 32-96 years]; P=.013). Anticipated amputation in this patient population requires a multidisciplinary approach with optimization of the patient's health. In the authors' clinical practice, the determination of the appropriate amputation level is performed individually for each patient, considering the risk factors identified in this study and the patient's expected mobilization potential, social background, and acceptance of a more proximal primary amputation level.
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http://dx.doi.org/10.3928/01477447-20151222-14DOI Listing
July 2016

Fluoroquinolones impair tendon healing in a rat rotator cuff repair model: a preliminary study.

Am J Sports Med 2014 Dec 20;42(12):2851-9. Epub 2014 Aug 20.

Laboratory for Soft Tissue Research, Hospital for Special Surgery, New York, New York, USA.

Background: Recent studies suggest that fluoroquinolone antibiotics predispose tendons to tendinopathy and/or rupture. However, no investigations on the reparative capacity of tendons exposed to fluoroquinolones have been conducted.

Hypothesis: Fluoroquinolone-treated animals will have inferior biochemical, histological, and biomechanical properties at the healing tendon-bone enthesis compared with controls.

Study Design: Controlled laboratory study.

Methods: Ninety-two rats underwent rotator cuff repair and were randomly assigned to 1 of 4 groups: (1) preoperative (Preop), whereby animals received fleroxacin for 1 week preoperatively; (2) pre- and postoperative (Pre/Postop), whereby animals received fleroxacin for 1 week preoperatively and for 2 weeks postoperatively; (3) postoperative (Postop), whereby animals received fleroxacin for 2 weeks postoperatively; and (4) control, whereby animals received vehicle for 1 week preoperatively and for 2 weeks postoperatively. Rats were euthanized at 2 weeks postoperatively for biochemical, histological, and biomechanical analysis. All data were expressed as mean ± standard error of the mean (SEM). Statistical comparisons were performed using either 1-way or 2-way ANOVA, with P < .05 considered significant.

Results: Reverse transcriptase quantitative polymerase chain reaction (RTqPCR) analysis revealed a 30-fold increase in expression of matrix metalloproteinase (MMP)-3, a 7-fold increase in MMP-13, and a 4-fold increase in tissue inhibitor of metalloproteinases (TIMP)-1 in the Pre/Postop group compared with the other groups. The appearance of the healing enthesis in all treated animals was qualitatively different than that in controls. The tendons were friable and atrophic. All 3 treated groups showed significantly less fibrocartilage and poorly organized collagen at the healing enthesis compared with control animals. There was a significant difference in the mode of failure, with treated animals demonstrating an intrasubstance failure of the supraspinatus tendon during testing. In contrast, only 1 of 10 control samples failed within the tendon substance. The healing enthesis of the Pre/Postop group displayed significantly reduced ultimate load to failure compared with the Preop, Postop, and control groups. There was no significant difference in load to failure in the Preop group compared with the Postop group. Pre/Postop animals demonstrated significantly reduced cross-sectional area compared with the Postop and control groups. There was also a significant reduction in area between the Preop and control groups.

Conclusion: In this preliminary study, fluoroquinolone treatment negatively influenced tendon healing.

Clinical Relevance: These findings indicate that there was an active but inadequate repair response that has potential clinical implications for patients who are exposed to fluoroquinolones before tendon repair surgery.
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http://dx.doi.org/10.1177/0363546514545858DOI Listing
December 2014

The human meniscus: a review of anatomy, function, injury, and advances in treatment.

Clin Anat 2015 Mar 14;28(2):269-87. Epub 2014 Aug 14.

Laboratory for Soft Tissue Research, Hospital for Special Surgery, 535 East 70th Street, New York, New York.

Meniscal injuries are recognized as a cause of significant musculoskeletal morbidity. The menisci are vital for the normal function and long-term health of the knee joint. The purpose of this review is to provide current knowledge regarding the anatomy and biomechanical functions of the menisci, incidence, injury patterns and the advancements in treatment options of meniscal injury. A literature search was performed by a review of PubMed, Google Scholar, MEDLINE, and OVID for all relevant articles published between 1897 and 2014. This study highlights the anatomical and biomechanical characteristics of the menisci, which may be relevant to injury patterns and treatment options. An understanding of the normal anatomy and biomechanical functions of the knee menisci is a necessary prerequisite to understanding pathologies associated with the knee.
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http://dx.doi.org/10.1002/ca.22456DOI Listing
March 2015

Allograft replacement for absent native tissue.

Sports Health 2013 Mar;5(2):175-82

Hospital for Special Surgery, New York, New York.

Context: Structural instability due to poor soft tissue quality often requires augmentation. Allografts are important biological substitutes that are used for the symptomatic patient in the reconstruction of deficient ligaments, tendons, menisci, and osteochondral defects. Interest in the clinical application of allografts has arisen from the demand to obtain stable anatomy with restoration of function and protection against additional injury, particularly for high-demand patients who participate in sports. Traditionally, allografts were employed to reinforce weakened tissue. However, they can also be employed to substitute deficient or functionally absent tissue, particularly in the sports medicine setting.

Objective: This article presents a series of 6 cases that utilized allografts to restore functionally deficient anatomic architecture, rather than just simply augmenting the degenerated or damaged native tissue. Detailed discussions are presented of the use of allografts as a successful treatment strategy to replace functionally weakened tissue, often after failed primary repairs.
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http://dx.doi.org/10.1177/1941738112456668DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3658384PMC
March 2013

Infection following simultaneous bilateral total knee arthroplasty.

J Arthroplasty 2013 Sep 9;28(8 Suppl):92-5. Epub 2013 Aug 9.

Department of Orthopaedic Surgery, Division of Adult Reconstruction and Joint Replacement, Hospital for Special Surgery, Weill Medical College of Cornell University, New York, New York.

Between 2000 and 2009, demographics, clinical characteristics, and infection details were compared among patients undergoing simultaneous BTKA (SBTKA), staged or UTKA. 2825 (16%) patients underwent SB, 1151 (6%) staged, and 13,983 (78%) UTKA. The overall infection rate following SBTKA (0.57%) was lower compared to staged (1.39%) or UTKA (1.1%) (P=0.01). The in-hospital infection rate was lower for the SB group (0.28% vs. 0.96% vs. 0.69%, respectively, P=0.01). The rate of late infections was comparable between the groups (0.32% vs. 0.43% vs. 0.43%, respectively, P=0.72). The rate of superficial infection was lower in the simultaneous cohort (0.28% vs. 1.04% vs. 0.87%; P=0.003). The overall rate of deep infection and reoperation for infection was similar among the groups. Among patients with late infection, age, gender, comorbidity score, time to infection, and most common organism isolated were not significantly different between the groups. Among infected patients after SB or staged TKA, 3 SB patients (18.75%), and 3 staged (20%) had bilateral involvement (P=1.0). Staged patients had more 2nd side infections, while simultaneous patients had more 1st side infections (P=0.02). Regression analysis showed that UTKA patients were 2.5 times more likely to develop in-hospital infection compared to SBTKA, while staged patients were almost 3.4 times more likely. Each additional hospital day increased the risk of late infection by 11.3%. SBTKA demonstrates an advantage over staged and maintains the safety profile of unilateral approaches with respect to infectious complications.
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http://dx.doi.org/10.1016/j.arth.2013.07.005DOI Listing
September 2013

Matrix generation within a macroporous non-degradable implant for osteochondral defects is not enhanced with partial enzymatic digestion of the surrounding tissue: evaluation in an in vivo rabbit model.

J Mater Sci Mater Med 2013 Oct 12;24(10):2429-37. Epub 2013 Jul 12.

Hospital for Special Surgery, 535 East 70th Street, New York, NY, 10021, USA.

Articular cartilage defects are a significant source of pain, have limited ability to heal, and can lead to the development of osteoarthritis. However, a surgical solution is not available. To tackle this clinical problem, non-degradable implants capable of carrying mechanical load immediately after implantation and for the duration of implantation, while integrating with the host tissue, may be viable option. But integration between articular cartilage and non-degradable implants is not well studied. Our objective was to assess the in vivo performance of a novel macroporous, nondegradable, polyvinyl alcohol construct. We hypothesized that matrix generation within the implant would be enhanced with partial digestion of the edges of articular cartilage. Our hypothesis was tested by randomizing an osteochondral defect created in the trochlea of 14 New Zealand white rabbits to treatment with: (i) collagenase or (ii) saline, prior to insertion of the implant. At 1 and 3-month post-operatively, the gross morphology and histologic appearance of the implants and the surrounding tissue were assessed. At 3 months, the mechanical properties of the implant were also quantified. Overall, the hydrogel implants performed favorably; at all time-points and in all groups the implants remained well fixed, did not cause inflammation or synovitis, and did not cause extensive damage to the opposing articular cartilage. Regardless of treatment with saline or collagenase, at 1 month post-operatively implants from both groups had a contiguous interface with adjacent cartilage and were populated with chondrocyte-like cells. At 3 months fibrous encapsulation of all implants was evident, there was no difference between area of aggrecan staining in the collagenase versus saline groups, and implant modulus was similar in both groups; leading us to reject our hypothesis. In summary, a porous PVA osteochondral implant remained well fixed in a short term in vivo osteochondral defect model; however, matrix generation within the implant was not enhanced with partial digestion of adjacent articular cartilage.
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http://dx.doi.org/10.1007/s10856-013-4999-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3839287PMC
October 2013

Epidemiology of injuries and prevention strategies in competitive swimmers.

Sports Health 2012 May;4(3):246-51

Laboratory for Soft Tissue Research, Hospital for Special Surgery, New York, New York.

Context: Competitive swimmers are predisposed to musculoskeletal injuries of the upper limb, knee, and spine. This review discusses the epidemiology of these injuries, in addition to prevention strategies that may assist the physician in formulating rehabilitation programs for the swimmer following an injury.

Evidence Acquisition: A literature search was performed by a review of Google Scholar, OVID, and PubMed articles published from 1972 to 2011.

Results: This study highlights the epidemiology of injuries common to competitive swimmers and provides prevention strategies for the sports health professional.

Conclusions: An understanding of swimming biomechanics and typical injuries in swimming aids in early recognition of injury, initiation of treatment, and design of optimal prevention and rehabilitation strategies.
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http://dx.doi.org/10.1177/1941738112442132DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3435931PMC
May 2012

The basic science of the patella: structure, composition, and function.

J Knee Surg 2012 May;25(2):127-41

Laboratory for Soft Tissue Research, Hospital for Special Surgery, New York, New York 10021, USA.

The patella is the largest sesamoid bone in the body. The patellofemoral joint provides an integral articulating component of the extensor mechanism of the knee joint. A detailed description of patella anatomy, embryology and development, neurovascular anatomy, biomechanical function, and imaging modalities is provided in this article. Common patellar pathologies such as patellar instability, trochlear dysplasia, patella alta and baja, and patellofemoral joint arthritis as well as patellofemoral arthroplasty as a treatment option are also discussed. An understanding of the normal anatomy and biomechanics of the patella is a necessary prerequisite for understanding the pathogenesis of disorders involving the knee.
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http://dx.doi.org/10.1055/s-0032-1313741DOI Listing
May 2012

Femoral neuropathy following total hip arthroplasty: review and management guidelines.

Acta Orthop Belg 2012 Apr;78(2):145-51

Laboratory for Soft Tissue Research, Hospital for Special Surgery, New York City, NY 10021, USA.

Femoral neuropathy following primary or revision total hip arthroplasty (THA) is a rare but acknowledged complication. Treatment of femoral neuropathy has long been debated and there is a paucity of accepted principles on which to base management. Currently, no definitive management protocol exists in the literature. A literature search was performed by a review of PubMed, Google Scholar and OVID articles published from 1972-2011. The literature reports an incidence rate of femoral neuropathy following THA ranging from 0.1 to 2.4 percent. Determining the precise aetiology, establishing a diagnosis and subsequent treatment of femoral nerve injury remains a difficult task, with conservative management remaining the treatment benchmark. In this review, we aim to summarise the aetiologies and risk factors associated with femoral neuropathy following THA and provide management guidelines.
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April 2012

A novel macroporous polyvinyl alcohol scaffold promotes chondrocyte migration and interface formation in an in vitro cartilage defect model.

Tissue Eng Part A 2012 Jun 15;18(11-12):1273-81. Epub 2012 May 15.

Hospital for Special Surgery, New York, New York, USA.

Scaffold-cartilage integration is critical for the clinical success of a scaffold used for the repair of a focal cartilage defect. In this study, a macroporous polyvinyl alcohol (PVA) scaffold was found to facilitate chondrocyte infiltration and interfacial matrix formation in a juvenile bovine in vitro cartilage defect model. These results were found to depend on the press-fit between the scaffold and the cartilage, pretreatment of the cartilage with collagenase prior to scaffold insertion, and chondrocyte preseeding of the scaffold. Infiltrated and preseeded chondrocytes in the scaffold survived for 6 weeks in culture and resulted in sufficient matrix at the interface to significantly increase the interface shear strength 30-fold that compared favorably with the interface shear strength of cartilage-cartilage constructs. The ability of this macroporous PVA scaffold to form a stable interface with articular cartilage demonstrates the potential use of this scaffold design for focal cartilage defect repair.
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http://dx.doi.org/10.1089/ten.TEA.2011.0276DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3360498PMC
June 2012

Differential cross-linking and radio-protective effects of genipin on mature bovine and human patella tendons.

Cell Tissue Bank 2013 Mar 21;14(1):21-32. Epub 2012 Feb 21.

Hospital for Special Surgery, 535 E. 70th Street, New York, NY, 10021, USA.

Gamma irradiation is a proven sterilization method, but is not widely used on allografts for anterior cruciate ligament reconstruction (e.g., patella tendon) due to radiation-induced decreases in mechanical strength. Addressing this drawback would improve the safety and supply of allografts to meet current and future demand. It was hypothesized that genipin-induced collagen cross-linking would increase the tensile modulus of patella tendon tissue such that 5 MRad gamma irradiation would not reduce the tissue mechanical strength below the original untreated values. Optimized genipin treatment increased the tensile modulus of bovine tendons by ~2.4-fold. After irradiation, genipin treated tissue did not significantly differ from native tissue, proving the hypothesis. Optimized genipin treatment of human tendons increased the tensile modulus by ~1.3-fold. After irradiation, both control and genipin-treated tissues possessed ~50-60% of their native tendon modulus, disproving the hypothesis. These results highlight possible age- and species- dependent effects of genipin cross-linking on tendon tissue. Cross-linking of human allografts may be beneficial only in younger donor tissues. Future research is warranted to better understand the mechanisms and applications of collagen cross-linking for clinical use.
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http://dx.doi.org/10.1007/s10561-012-9295-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3705212PMC
March 2013

Incorporation of phosphate group modulates bone cell attachment and differentiation on oligo(polyethylene glycol) fumarate hydrogel.

Acta Biomater 2012 Apr 8;8(4):1430-9. Epub 2012 Jan 8.

Department of Orthopedic Surgery, Mayo Clinic College of Medicine, 200 First Street SW, Rochester, MN 55905, USA.

In this work, we have investigated the development of a synthetic hydrogel that contains a negatively charged phosphate group for use as a substrate for bone cell attachment and differentiation in culture. The photoreactive, phosphate-containing molecule, bis(2-(methacryloyloxy)ethyl)phosphate (BP), was incorporated into oligo(polyethylene glycol) fumarate hydrogel and the mechanical, rheological and thermal properties of the resulting hydrogels were characterized. Our results showed changes in hydrogel compression and storage moduli with incorporation of BP. The modification also resulted in decreased crystallinity as recorded by differential scanning calorimetry. Our data revealed that incorporation of BP improved attachment and differentiation of human fetal osteoblast (hFOB) cells in a dose-dependent manner. A change in surface chemistry and mineralization of the phosphate-containing surfaces verified by scanning electron microscopy and energy dispersive X-ray analysis was found to be important for hFOB cell attachment and differentiation. We also demonstrated that phosphate-containing hydrogels support attachment and differentiation of primary bone marrow stromal cells. These findings suggest that BP-modified hydrogels are capable of sustaining attachment and differentiation of both bone marrow stromal cells and osteoblasts that are critical for bone regeneration.
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http://dx.doi.org/10.1016/j.actbio.2011.12.031DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3970912PMC
April 2012