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Orthopaedic Proceedings
Vol. 102-B, Issue SUPP_6 | Pages 87 - 87
1 Jul 2020
Ashjaee N Johnston G Johnston J
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Distal radius fracture is one of the most common fractures in older women (∼70,000 cases annually in Canada). Treatment of this fracture has been shifting toward surgery (mainly volar locking plate (VLP) technology), which significantly enhances surgeon's ability to maintain correction. However, current surgical outcomes are far from perfect. There is a need for an implant which maintains the corrected position (reduction), minimizes soft tissue disruption, and is technically easy to perform. A novel internal, composite-based implant was designed to achieve these ends. It is unclear, however, whether this novel implant offers similar fracture fixation as the VLP. As such, the objective of this research was to evaluate the fracture stability (assessed by calculating change in fracture length) of the novel implant and VLP under cyclic fatigue loading.

Specimens: Seven radius specimens derived from older female cadavers (mean = 82.3 years, SD = 11.3 years) were used for the experiment.

Preparation: A standardized dorsal wedge was removed from the cortex. The distance from the proximal and distal transverse osteotomies was 10 mm and was positioned 20 mm proximal to the tip of the radial styloid. The osteotomy removed all load-bearing capabilities of bone, equivalent to a worst-case-scenario for DRF fixation.

Simulated Loading: The proximal end of the radii was potted (fixed) and positioned in a material testing system. To mimic natural loading conditions, hands were cycled between −30°/30° flexion/extension, at 0.5 Hz, for 2000 cycles, while tension load was applied to the tendons (25-N constant force per tendon, 100-N in total).

Mechanical testing outcomes: A position tracking sensor used to measure change in fracture length. This change, as a function of number of cycles, was used to assess implant resistance to fatigue loading.

Statistical Analysis: A paired student t-test was used to compare the change in fracture length. Level of significance was determined as 5% (p < 0.05).

Changes in fracture fracture-length for both the novel implant and plate is shown in Table 1. The paired t-test indicated significant differences between the two groups in terms of change in fracture length (p = 0.026).

The outcome of the novel implant ranged from very stable (change in fracture-length = 0.01 mm) to highly un-stable (2.88 mm). We believe the reason for this variance, at least in part, originates from the surgical procedures. Presumably, given that one very strong stabilization (0.01 mm) and one acceptable stabilization (0.37 mm) was obtained, future research directed towards surgical procedures may improve fracture stability.

For any figures or tables, please contact authors directly.


Orthopaedic Proceedings
Vol. 102-B, Issue SUPP_6 | Pages 86 - 86
1 Jul 2020
Ashjaee N Johnston G Johnston J
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Distal radius fractures are the most common osteoporotic fractures among women. The treatment of these fractures has been shifting from a traditional non-operative approach to surgery, using volar locking plate (VLP) technology. Surgery, however, is not without risk, complications including failure to restore an anatomic reduction, fracture re-displacement, and tendon rupture. The VLP implant is also marked by bone loss due to stress-shielding related to its high stiffness relative to adjacent bone. Recently, a novel internal, composite-based implant, with a stiffness less than the VLP, was designed to eradicate the shortcomings associated with the VLP implant. It is unclear, however, what effect this less-stiff implant will have upon adjacent bone density distributions long-term. The objective of this study was to evaluate the long-term effects of the two implants (the novel surgical implant and the gold-standard VLP) by using subject-specific finite element (FE) models integrated with an adaptive bone formation/resorption algorithm.

Specimen: One fresh-frozen human forearm specimen (female, age = 84 years old) was imaged using CT and was used to create a subject-specific FE model of the radius.

Finite element modeling: In order to simulate a clinically relevant (unstable) fracture of the distal radius, a wedge of bone was removed from the model, which was approximately 10 mm wide and centered 20 mm proximal to the tip of the radial styloid.

Bone remodeling algorithm: A strain-energy density (SED) based bone remodeling theory was used to account for bone remodeling. With this approach, bone density decreased linearly when SED per bone density was less than 67.5 µJ/g and increased when it was more than 232.5 µJ/g. When it was in the lazy zone (67.5 to 232.5 µJ/g), no changes in density occurred.

Boundary conditions: A 180 N quasi-static force representing the scaphoid, and a 120 N quasi-static force representing the lunate was applied to the radius. The midshaft of the radius was constrained.

FE outcomes: To examine the effects of stress shielding associated with each implant, the long-term changes of bone density within proximal transverse cross-sections of radius were inspected. The regional density analysis focused on three transverse cross-sections. The transverse cross-sections were positioned proximal to the subchondral plate, and were distanced 50 (cross-section A), 57 (cross-section B), and 64 mm (cross-section C) from the subchondral endplate.

For both implants in all three cross-sections, cortical bone was reserved completely at the volar side. On the dorsal side, the cortical bone was completely resorbed in the VLP model. In all cross-sections, the averaged resultant density was higher for the “novel implant”. The difference ranged from 33% (cross-section A) to 36% (cross-section C) in favor of the “novel implant”. On average, the density values of the novel implant were 34% higher in transverse cross-sections (A, B, and C).

This study showed that the novel implant offered higher density distributions compared to the VLP, which suggests that the novel implant may be superior to the VLP in terms of avoiding stress shielding.


Orthopaedic Proceedings
Vol. 98-B, Issue SUPP_21 | Pages 52 - 52
1 Dec 2016
Abou-Ghaida M Johnston G Stewart S
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Displaced distal radial fractures in adults are commonplace. Acknowledging that satisfactory radiographic parameters typically will beget satisfactory functional outcomes, management of these fractures includes a reduction followed by either cast/splint immobilisation or internal fixation. While we can generally rely on internal fixation to maintain the reduction the same is not true of cast immobilisation. There are, however, limited data defining the fate of a fracture reduction in those treated in a cast and up to the time of radial union. Traditional practice is to recommend six weeks of immobilisation. Our goal was to detail the radiographic patterns of change in the radiographic parameters of radial inclination (RI), ulnar variance (UV) and radial tilt (RT) over the first twelve weeks in women fifty years old and older who had sustained a displaced distal radial fracture.

We examined serial standard PA and lateral distal radius radiographs of 647 women treated by closed reduction and casting for a displaced fracture of the distal radius. Measurements of RI, UV and RT from standardised radiographs were made immediately post-reduction as well as, as often as possible/feasible, at 1,2,3,6,9 and 12 weeks post fracture. All measurements were made by the senior author (accuracy range: 2 degrees for RI, 1 mm for UV and 4 degrees for RT, in 75% of cases). The primary outcome measure was the change in fracture position over time. Secondary outcomes included changes related to age group; known bone density; the relation to associated ulnar fractures; and independence of the variables of RI, UV and RT.

The mean immediate post-reduction values for RI, UV and RT were 21 degrees, 1.5 mm, and −6 degrees, respectively. These all changed in the first six weeks, and did not in the second six week period. The mean change in RI was 3 degrees, 60% of the change occurring in the first week post-reduction; only 0.3 degrees of change was noted beyond three weeks. The mean UV increased by 2.2 mm over the first 6 weeks, 23% in the first week post reduction. The mean RT change of 7.7 degrees was also gradual over the first 6 weeks, with no significant change afterwards. The RI changes identified were not influenced by patient age, while UV and RT changes were greater in older groups. Those fractures of the distal radius associated with a distal ulnar shaft or neck fracture did not lose radial inclination over the study period.

We have defined patterns of loss of reduction that commonly occur post reduction of a displaced distal radius fracture in women fifty years and older. Such patterns ought to guide our closed management of distal radial fractures, whether by altering the duration or method of casting. Women fifty years old and older, and physicians alike, must be advised that conventional casting post distal radial fracture reduction unreliably maintains fracture reduction.


Orthopaedic Proceedings
Vol. 98-B, Issue SUPP_21 | Pages 44 - 44
1 Dec 2016
Sims L Johnston G Stewart S
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Distal ulna fractures (DUF) are commonly associated with distal radius fractures (DRF). Recent evidence suggests that the presence and type DUFs may impact the outcomes of associated healing distal radius fractures. There is currently no standardised and validated classification system for characterising distal ulna fractures. The purpose of this study was to assess the validity of our newly created inclusive classification system for distal ulna fractures, shown to influence distal radius fracture outcomes in a previous study.

A classification system for distal ulna fractures was devised based on fracture pattern and location. Type 1 fractures were those in the ulnar styloid, with type 1a involving its apex and Type 1b being in the body of the styloid; Type 2 fractures are proximal to the styloid and involve the ulnar fovea, with type 2t adopting a transverse pattern and type 2o an oblique pattern; Type 3 fractures involve the ulnar head; and type 4 fractures were those proximal to the head, with 4n being through the neck (including the physeal scar) and 4s involving the distal shaft. A questionnaire was distributed to all members of the Canadian Orthopaedics Association in both French and English, asking participants to evaluate 29 radiographic images of distal ulnar fractures. Only one answer was deemed to be correct for all but one radiograph, while for one radiograph there were three fracture types to be identified.

There were 129 respondents to the questionnaire. For Type 1a fractures, of the 606 radiographs evaluated 90% answered correctly and 73% of the incorrect answers identified a Type 1b fracture pattern. For Type 1b fractures, of 600 radiographs, 83% were answered correctly, the incorrect answers including Types 1a and 2t fracture types. For Type 2t fractures, of 593 radiographs, 76% were answered correctly, and 90% of the incorrect answers identified a Type 1b fracture pattern. For Type 2o fractures, of 716 radiographs, 87% were answered correctly, and 91% of the incorrect answers were identified as either Type 4n or 2t. For Type 4n fractures, of the 465 radiographs evaluated 84% answered correctly and 80% of the incorrect answers identified a Type 4s fracture pattern. For Type 4s fractures, of the 355 radiographs evaluated 99% answered correctly and 100% of the incorrect answers identified a Type 4n fracture pattern. The results will guide the authors to further distinguish between the definitions of Types 1b and 2t, and 4n and 4s.

The Canadian orthopaedic community has demonstrated how readily they can reproduce this new classification system, previously shown to be predictive of radiographic outcomes for the associated distal radius fractures. This new classification is an inclusive and simple way of characterising these fractures with high reliability. This provides treating physicians with a uniform way of describing these fractures, useful both in predicting outcomes and conducting future research.


Orthopaedic Proceedings
Vol. 93-B, Issue SUPP_IV | Pages 582 - 582
1 Nov 2011
Van der Merwe JM Beavis RC Johnston G
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Purpose: Due to bed and resource constraints at the Royal University Hospital in Saskatoon, Saskatchewan, we have seen an increase in utilization of the day surgery program for acute Orthopedic traumatic injuries in ambulatory patients. The purpose of this study was to assess patient satisfaction with the Saskatoon Health Region Orthopedic trauma day surgery program by collecting data pertaining to wait-times, demographics, communication, coping skills at home and pain management.

Method: A patient-oriented questionnaire was devised and administered to eligible adult patients presenting for day surgery Orthopedic Trauma procedures over a three month period. Inclusion criteria included age greater than 18 and written english comprehension. Between July 12 and October 2, 2009, 45 patients consented to participate. The questionnaire was formulated to encapsulate all the potential concerns associated with the day-surgery program, which included expected wait-times, pain control, and communication between the orthopedic surgeon and the patient. Demographics and actual wait-times were obtained from hospital data.

Results: There was a marked discrepancy between the actual and anticipated waiting times for day surgery. However, 64% of the patients were still satisfied with the waiting times despite the difference. Seventy three percent of patients did not think that admission to hospital would lead to earlier surgery. There was an obvious difference in demographics with 53% of patients living outside city limits. Demographics played an important role in patient satisfaction. Patients living within the city limits had a better experience compared to patients living outside city limits. Patients did have difficulty managing at home. The overall satisfaction was 68% at the conclusion of the study.

Conclusion: Patients were overall satisfied with the day surgery program. We have identified several areas where we can improve. This involve better pain management, better communication and assessment of the bio-socioeconomic circumstances of patients. We will also have a lower threshold for admitting non residents of Saskatoon. We will relay a more realistic timeframe for surgery, as calculated in the study, to patients .


Orthopaedic Proceedings
Vol. 91-B, Issue SUPP_II | Pages 243 - 243
1 May 2009
Bois A Johnston G Classen D
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Spontaneous flexor tendon ruptures of the hand are uncommon and the current understanding of these ruptures is incomplete.

The purpose of this study is to report five cases of spontaneous flexor tendon rupture in the hand, and to contrast the findings to those in the literature.

A retrospective review of patients with flexor tendon injuries referred to our hand surgeons identified five patients who sustained a spontaneous rupture of the flexor digitorum profundus tendon. A literature search found a total of nineteen articles describing spontaneous tendon ruptures that met our criteria.

We report five cases of spontaneous rupture involving the flexor digitorum profundus tendon. One case involves an abnormal intertendinous connection between the ring and small finger profundus tendons and another involves a lumbrical muscle variant. To our knowledge, the latter has not been reported in association with spontaneous tendon rupture. In reviewing the literature for spontaneous flexor tendon ruptures, a total of fifty spontaneous ruptures in forty-three cases was found. The majority involve the profundus tendon of the small finger in the palm. The ruptures most often occur during periods of peak strain, but can also occur without identifiable trauma.

This study provides a detailed overview of spontaneous flexor tendon ruptures in the hand not found in the literature. The pathogenesis of spontaneous tendon ruptures is still unclear and is likely multifactorial. Although spontaneous flexor tendon ruptures of the hand are uncommon, these ruptures occur more often than one might recognise.


Orthopaedic Proceedings
Vol. 91-B, Issue SUPP_II | Pages 237 - 237
1 May 2009
Pally E Johnston G
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The purpose for this study was to investigate the site marking practice for emergent and non-emergent orthopedic surgery at the authors’ orthopedic teaching program. One author attended surgeries at two hospitals in 2006, documenting the presence or absence of an unambiguous mark in the prepped and draped surgical field. Although emergent and elective cases were “chosen”, there was no intentional selection bias.

Forty-eight surgeries by eleven surgeons were evaluated. After draping a mark was visible in twelve of eighteen (67%) emergent cases, and twenty-seven of thirty (90%) non-emergent cases. In the nine cases in which no mark was visible, two had been draped out, one had been washed off, two had never been marked, and in four cases the cause was uncertain.

The authors would suggest that surgeons were near fully “compliant” with the COA protocol in non-emergent cases, but “complacent” in emergent ones. Wrong site surgery is an event that results in irrevocable harm to the patient - orthopaedic surgeons should recognise the value of pre-operative skin marking for all procedures, and re-evaluate their own personal practices in light of our results.