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Orthopaedic Proceedings
Vol. 106-B, Issue SUPP_18 | Pages 51 - 51
14 Nov 2024
Shayestehpour H Shayestehpour MA Wong C Bencke J Rasmussen J
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Introduction

Adolescent Idiopathic Scoliosis (AIS) is a three-dimensional deformity of the spine with unclear etiology. Due to the asymmetry of lateral curves, there are differences in the muscle activation between the convex and concave sides. This study utilized a comprehensive thoracic spine and ribcage musculoskeletal model to improve the biomechanical understanding of the development of AIS deformity and approach an explanation of the condition.

Methods

In this study, we implemented a motion capture model using a generic rigid-body thoracic spine and ribcage model, which is kinematically determinate and controlled by spine posture obtained, for instance, from radiographs. This model is publicly accessible via a GitHub repository. We simulated gait and standing models of two AIS (averaging 15 years old, both with left lumbar curve and right thoracic curve averaging 25 degrees) and one control subject. The marker set included extra markers on the sternum and the thoracic and lumbar spine. The study was approved by the regional Research Ethics Committee (Journal number: H17034237).


Bone & Joint Research
Vol. 12, Issue 12 | Pages 722 - 733
6 Dec 2023
Fu T Chen W Wang Y Chang C Lin T Wong C

Aims

Several artificial bone grafts have been developed but fail to achieve anticipated osteogenesis due to their insufficient neovascularization capacity and periosteum support. This study aimed to develop a vascularized bone-periosteum construct (VBPC) to provide better angiogenesis and osteogenesis for bone regeneration.

Methods

A total of 24 male New Zealand white rabbits were divided into four groups according to the experimental materials. Allogenic adipose-derived mesenchymal stem cells (AMSCs) were cultured and seeded evenly in the collagen/chitosan sheet to form cell sheet as periosteum. Simultaneously, allogenic AMSCs were seeded onto alginate beads and were cultured to differentiate to endothelial-like cells to form vascularized bone construct (VBC). The cell sheet was wrapped onto VBC to create a vascularized bone-periosteum construct (VBPC). Four different experimental materials – acellular construct, VBC, non-vascularized bone-periosteum construct, and VBPC – were then implanted in bilateral L4-L5 intertransverse space. At 12 weeks post-surgery, the bone-forming capacities were determined by CT, biomechanical testing, histology, and immunohistochemistry staining analyses.


Orthopaedic Proceedings
Vol. 105-B, Issue SUPP_7 | Pages 122 - 122
4 Apr 2023
Schwarzenberg P Colding-Rasmussen T Hutchinson D Mischler D Horstmann P Petersen M Malkock M Wong C Varga P
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The objective of this study was to investigate how a new customizable light-curable osteosynthesis method (AdFix) compared to traditional metal hardware when loaded in torsion in an ovine phalanx model.

Twenty-one ovine proximal phalanges were given a 3mm transverse osteotomy and four 1.5mm cortex screws were inserted bicortically on either side of the gap. The light-curable polymer composite was then applied using the method developed by Hutchinson [1] to create osteosyntheses in two groups, having either a narrow (6mm, N=9) or a wide (10mm, N=9) fixation patch. A final group (N=3) was fixated with conventional metal plates. The constructs were loaded in torsion at a rate of 6°/second until failure or 45° of rotation was reached. Torque and angular displacement were measured, torsional stiffness was calculated as the slope of the Torque-Displacement curve, and maximum torque was queried for each specimen.

The torsional stiffnesses of the narrow, wide, and metal plate constructs were 39.1 ± 6.2, 54.4 ± 6.3, and 16.2 ± 3.0 Nmm/° respectively. All groups were statistically different from each other (p<0.001). The maximum torques of the narrow, wide, and metal plate constructs were 424 ± 72, 600 ± 120, and 579 ± 20 Nmm respectively. The narrow constructs were statistically different from the other two (p<0.05), while the wide and metal constructs were not statistically different from each other (p=0.76).

This work demonstrated that the torsional performance of the novel solution is comparable to metal fixators. As a measure of the functional range, the torsional stiffness in the AdhFix exceeded that of the metal plate. Furthermore, the wide patches were able to sustain a similar maximum toque as the metal plates. These results suggest AdhFix to be a viable, customizable alternative to metal implants for fracture fixation in the hand.


Orthopaedic Proceedings
Vol. 99-B, Issue SUPP_5 | Pages 19 - 19
1 Mar 2017
Sieberg C Klajn J Wong C Bowen G Simons L Millis M
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Purpose

Factors contributing to chronic postoperative pain (CPOP) are poorly defined in young people and developmental considerations are poorly understood. With over 5 million children undergoing surgery yearly and 25% of adults referred to chronic pain clinics identifying surgery as the antecedent, there is a need to elucidate factors that contribute to CPOP in young people. The present study includes patients undergoing hip preservation surgery at a children's hospital.

Methods

The HOOS and the SF-12 Health Survey were administered to 614 patients prior to surgery with 422 patients completing follow-up data (6-months, 1-year, and 2-years post-surgery). Examining baseline characteristics for those who completed follow-up versus those who did not, the only significant difference was that patients with more than one surgery were less likely to complete follow-up measures. Pain, quality of life, and functioning across time were examined using SAS PROC TRAJ procedure, a mixture model that estimates a regression model for each discrete group within the population. Longitudinal pain trajectories were empirically grouped. Baseline preoperative characteristics of age, gender, preoperative pain, quality of life, functioning, and mental health that could potentially distinguish trajectory groups were examined.


Orthopaedic Proceedings
Vol. 93-B, Issue SUPP_IV | Pages 573 - 573
1 Nov 2011
Friedmann D Gefen A Turcotte RE Wunder JS Roberge D Ferguson P O’Sullivan B Catton C Freeman C Deheshi B Griffin A Riad S Wong C
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Purpose: Lymphoedema is a serious potential complication of the management of extremity soft tissue sarcoma (STS) about which relatively little is known. We aimed to evaluate the incidence of lymphoedema, its severity and associated risk factors following limb salvage for extremity STS.

Method: Lymphoedema severity (EORTC/RTOG) was recorded prospectively in two databases of soft tissue sarcoma patients. Patient’s demographics, tumor characteristics, surgical procedures, radiotherapy dosage, complications and functional outcomes (MSTS, TESS) were also prospectively collected. Charts were also retrospectively abstracted for body mass index (BMI) and medical comorbidities.

Results: 289 patients had sufficient data for analysis (158 male). Mean age was 53 (range 16–88). Mean BMI was 27.4 (range: 15.8–52.1). 209 had lower extremity tumors and 80, upper. Mean tumor size was 8.1 cm (range 1.0–35.6 cm). 77 had no adjuvant radiation, 180 had 50 Gy and 32, 66 Gy. The incidence of lymphoedema was found to be 28.7% (58 mild, 22 moderate, 3 severe). Mean MSTS score was 32 (range: 11–35) and TESS was 89.4 (range: 32.4–100). We grouped cases with lymphoedema grade 0–1 and 2–3. Univariate analysis found significant correlations between the severity of lymphedema and tumor size ≥5 cm (p=0.011), deep location (no patient with a superficial tumor had severe lymphoedema, p=0.001), and radiation dosage 50 vs 66 Gy (p=0.021) but not between upper vs lower extremity (p=0.06).

Conclusion: 9% of STS studied developped significant post-treatment lymphoedema. Large, deep tumors and necessity for 66 Gys were most at risk. This group could be targeted for prophylatic intervention.


Orthopaedic Proceedings
Vol. 93-B, Issue SUPP_III | Pages 266 - 266
1 Jul 2011
Abatzoglou S Adoubali A Wong C Isler M Turcotte RÉ
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Purpose: Management of local recurrence (LR) remains unclear. Optimal management of primary tumour by specialised teams minimises this risk. However, previous treatments may impact on the available options when LR is encountered. We thus studied the outcome of this population with recurrent STS.

Method: Retrospective review was carried based on our prospective sarcoma databases. DFSP and ALT were excluded. Among 618 primarily managed STS we found 35 cases of local recurrences (5.7%). Median f-up after LR was 14 mos (0–98).

Results: Twenty were female. Mean age was 54 (Range 15 – 92). 22 involved lower limb, 11 upper limb and 2 the trunk. Mean delay from original surgery was 23 mos (3–75) and the mean size of LR was 4.7 cm (0.4–28.0 cm). Primary tumours were superficial in 4 and deep in 31 while recurrences were found superficial in 8 and deep in 26. Most frequent histology was MFH 8, Leiomyosarcoma 6, Liposarcoma, synovial sarcoma and MPNST had 4 each. 84% were high grade. Only 23 showed no meta-static disease at time LR was diagnosed. All 5 pts without initial RT got RT for their LR. 7 pts with therapeutic level of RT to the primary tumour got full course of RT as well for their LR. 11 did not undergo surgery. 6/18 who had initial RT underwent amputation as opposed to 0/6 who did not. Trend to amputate was for younger age, deep and large tumour and previous RT. Ultimatly, 21(60%) locally recurrent tumours showed metastatic disease; 6 prior diagnosis of LR, 6 concomitantly and 9 after with an average delay of 17 months (1–24). 6 pts developed additional local recurrences.

Conclusion: Although infrequent local recurrence correlates with impaired outcome. Albeit challenging, limb salvage and additional radiotherapy remain possible despite optimal multi modality management of the initial tumour.


Orthopaedic Proceedings
Vol. 92-B, Issue SUPP_I | Pages 39 - 39
1 Mar 2010
Latt D Turcotte RE Isler MH Wong C
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Purpose: To review all cases of soft tissue sarcoma of the foot and ankle treated in a specialized musculoskeletal oncology practice over a 15 year period. This was done to gain insight into the presentation, treatments, and outcomes for this rare disease.

Method: 16 patients (mean age at presentation 43, range 15–79, 9 female) were identified from our database of nearly 1000 cases of musculoskeletal tumors (1.6%). 8 were referred following unplanned excision and 3 after local recurrence. The pathologic diagnoses included synovial sarcoma (n=7), clear cell sarcoma (n=2), fibrosarcoma (n=2), and other diagnosis (n=6). AJCC stages were: Ia – 2, IIb – 7, IIc – 1, III – 4, and IV – 2. The tumors were mostly located on the medial (n=7) or dorsal (n=6) aspects of the foot. They were equally distributed among the hindfoot, midfoot, and forefoot.

Results: Treatment consisted of resection in 10, resection and arthrodesis in 3, and amputation in 4 patients. The resections were intralesional in 4 patients, marginal in 7 and wide in 6. Among the 13 limb salvage patients, one needed skin grafting and 9 required free tissue transfers. Radiation therapy was used preoperatively in 5 and post-operatively in 7 cases. Neoadjuvant chemotherapy was given to 2 patients. Followup averaged 6 years (range 2–15). Local recurrence occurred in 2 patients (17%). One was treated with re-excision and one with amputation. Lung metastases occurred in 4 patients. At last followup: 11 of the 17 patients were alive without disease, 2 with disease, and 4 had died of their disease. No local recurrence in primarily treated tumor led to metastasis. Postoperative MSTS 1987 and TESS scores averaged 28 and 90% respectively.

Conclusion: Soft tissue sarcoma of the foot is rare. Surgical treatment is challenging due to the complex anatomy and limited soft tissues. Limb salvage often required accepting intralesional or marginal resections and using free tissue transfer. The addition of radiation therapy yielded an acceptable local control rate and very good functional outcomes. However, the impact this limb salvage approach on mortality is not clear.


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Early operative debridement is a major determinant of mortality in necrotizing fasciitis. However, early recognition is difficult. The aim of our study is to develop a novel scoring system for distinguishing necrotizing fascitis from other soft tissue infections based on routine laboratory findings on admission.

The developmental cohort consisted of 89 consecutive patients with necrotizing fasciitis treated between January 1997 and August 2002. Control patients (n=225) were randomly selected from patients admitted with the diagnosis of cellulitis or abscesses during the same period. Their haematological and biochemical results done on admission were analyzed.

Total white cell count, haemoglobin, sodium, glucose, creatinine and C-reactive protein were selected as predictors. The final constructed model was reliable and discriminated well between patients with necrotizing fascitis from those with other benign soft tissue infections (Area under the receiver-operating characteristic (ROC) curve, 0.98). The LRINEC score was derived from this model and was validated in a separate cohort of patients from a different hospital (56 patients with necrotizing fasciitis and 84 control patients). Based on the calculated probability we stratified patients with soft tissue infections into 3 risks categories: high (LRINEC score _8), intermediate (LRINEC score 6–7) and low (LRINEC score _ 5) risks groups.

The LRINEC score is a robust score capable of detecting even clinically early cases of necrotizing fasciitis. On admission, patients in the intermediate and especially the high risks groups should be subjected to a frozen section biopsy or MRI scans with an aim of early diagnosis, debridement and ultimately


Orthopaedic Proceedings
Vol. 88-B, Issue SUPP_III | Pages 452 - 452
1 Oct 2006
Wong E Wong C
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Introduction The biomechanical properties of biologic cages made of femoral ring allograft in providing immediate stability for lumbar fusion as compared to bovine xenograft, titanium and polyethylether ketone (PEEK) cages are unknown. Biomechanical comparisons were done of lumbar constructs to determine their adequacy in providing immediate stability for fusion mass and demonstrate the need for supplemental posterior fixation.

Methods Fusion constructs were evaluated in 40 Merino sheep as lumbar spine models. Discectomy was performed on multisegmental specimens. Femoral ring allograft, bovine xenograft, titanium cage (Syncage) and Polyethylether ketone / PEEK cage (Plivios) were inserted. Dual X ray absorptiometry assessment of bone mineral content was performed .Testing was one for insertional torque and pullout strengths. Static testing consisted of flexion and extension 2Nm moment and100Nm compression load, bilateral axial rotation pure 5.5 Nm moment and lateral bending pure moments 1.1Nm moment and100Nm compression loads. Dynamic testing was done to detemine long term properties of the construct.

Results Interbody cages performed equivalently to femoral ring allograft. Bovine xenograft had lower stability compared to the rest. Posterior supplemental transpedicular fixation achieved increased stability in flexion, extension & lateral bending. Reduced stability was observed in all contructs with cyclical loading. The stabilizing effects were affected by the disc space distraction and facet joints. The titanium cage had significantly greater median pullout force compared to the others.

Discussion Femoral ring allograft is valid alternative to titanium and PEEK cages. It is able to provide adequate immediate stability. Supplemental posterior fixation resulted in further rigidity of the constructs.


Orthopaedic Proceedings
Vol. 87-B, Issue SUPP_III | Pages 251 - 251
1 Sep 2005
Jukema G Wong C Steenvoorde P v Dissel J
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Background: The experimental use of maggots (sterile larvae of Lucilia sericata) can prevent the amputation of an extremity in case of severe infection after trauma injury. Maggots destroy bacteria by secreting enzymes such as tryptase, peptidase and lipase. An alkaline environment is created by the secretion of allantoin, ammonia and calcium carbonate, which reduces bacterial growth and stimulates new formation of granulation tissue.

Material and Methods: In the period 4.1999–12.2003 42 patients (mean age 54 yrs (25–83), were included in cur prospective study for maggot treatment of severe infections after trauma (Osteomyelitis n=26, lower leg 13x, femur 6x, pelvis 4x, upper extremity 3x), necrotizing fasciitis n=7, soft tissue infection n=3, gangrene n-3, ulcus cruris n=3). Maggots were applied to the wound in a polyvinyl alcohol bag (Biobag) and were replaced every 3–4 days.

Results: The mean duration of treatment was 32,1 days (n~37) for the patients who had received one continuous treatment and 62,2 days if more treatments were applied (n=5). The average number of biobag changes per patient was 11.5 (range 4–30); the average number of maggots applied per patient was 863 (range 80–6840). In only 1 patient with osteomyelitis a lower leg amputation was necessary (1/26=3.8%) although in almost patients there was severe (multiple) co morbidity.

Conclusion: In our study the experimental use of maggots could reduce the amputation rate of limbs in case of severe infections after trauma. Our laboratory research investigations with analysis of the secreting enzymes of maggots will be presented to support that this «ancient» method has a place in modern traumatology to diminish invalidating amputations.


Orthopaedic Proceedings
Vol. 84-B, Issue SUPP_III | Pages 239 - 239
1 Nov 2002
Lu D Luk K Wong C Cheung K Wong Y Leong J
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In scoliosis, it is well known that lateral deformity is coupled with vertebral axial rotation. Coupled motion in the sagittal plane, however, has not been investigated.

Objective: To investigate the behavior of the sagittal alignment changes when coronal deformity was corrected in idiopathic thoracic scoliosis.

Method: 36 idiopathic scoliosis patients with thoracic curves were examined before surgery. Coronal deformity was corrected using the Fulcrum Bending technique1, and biplane radiographs were taken to monitor the correction of the deformity, as well as the coupled sagittal alignment changes. Sagittal alignment was measured from T4/T5 to T12 using Cobb’s method. Difference of less or equal to 3 degrees between two measurements was treated as no change. Results were compared with those measured from standing lateral radiographs prior to and at 1 week after surgery (Posterior correction and fusion with ISOLA: n=15; CD-Horizon: n=8; Moss-Miami: n=11, USS: n=2). Pearson correlation was used for statistical analysis.

Results: (A) When scoliosis was corrected under fulcrum bending, the coupled changes in the thoracic kyphosis were decreased if it was greater than 20 degrees (n= 18), increased if less than 20 degrees (n= 2), and kept no change if it was around 20 degrees (n= 16). These changes were not related to the amount of deformity or flexibility in the coronal plane (Table I). (B) There was strong relationship between the sagittal alignment measured on the pre-operative fulcrum bending and postoperative lateral radiographs (P< 0.01). However, the final sagittal alignment was neither correlated with the magnitude or flexibility of the coronal deformity, nor the instrumentation applied (P> 0.05)

Discussion: A coupling exists between the coronal lateral deformity and the sagittal alignment in thoracic scoliosis. It seems that the sagittal alignment in a scoliotic spine tends to “normalize” with correction of the deformity: a “hyper-kyphotic” spine tends to reduce, and a “hypo-kyphotic” one tends to increase the kyphosis. Post-operative sagittal alignment seems to be decided by the coupling motion and the amount of curvature of the pre-bent rod, as neither the nature (degree or flexibility or curve pattern) of the coronal deformity nor the choice of instrumentation were related to the post-operative sagittal alignment.


The Journal of Bone & Joint Surgery British Volume
Vol. 78-B, Issue 2 | Pages 210 - 212
1 Mar 1996
Laupacis A Rorabeck C Bourne R Tugwell P Bullas R Rankin R Vellet AD Feeny D Wong C

We randomised 250 patients undergoing unilateral, elective hip arthroplasty for osteoarthritis to receive either a cemented or a non-cemented Mallory Head prosthesis. Aspirin was used as prophylaxis against thromboembolism during the first half of the study and adjusted-dose warfarin during the second half. Postoperatively, all patients were asked to have bilateral venography and 80% agreed. All were evaluated clinically for pulmonary embolism.

There was no difference in the frequency of deep-venous thrombosis between the two groups (50% cemented v 47% non-cemented, p = 0.73; 95% CI of the difference −13.6% to 19.3%). Three of the 64 patients (5%) in whom venography had demonstrated isolated distal thrombi developed pulmonary emboli.