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Orthopaedic Proceedings
Vol. 98-B, Issue SUPP_14 | Pages 9 - 9
1 Jul 2016
Jawalkar H Aggarwal S Bilal A Oluwasegun A Tavakkolizadeh A Compson J
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Scaphoid fractures accounts for approximately 15% of all fractures of hand and wrist. Proximal pole fractures represent 10–20% of scaphoid fractures. Non –operative treatment shows high incidence of non-union and avascular necrosis. Surgical intervention with bone graft is associated with better outcome. The aim of this study was to evaluate the radiological and functional outcome of management of proximal pole scaphoid non-union with internal fixation and bone grafting. We included 35 patients with proximal pole scaphoid non-union (2008–2015). All patients underwent antegrade headless compression screw fixation and bone grafting at King's College Hospital, London (except one, who was fixed with Kirschner wire). 33 patients had bone graft from distal radius and two from iliac crest. Postoperatively patients were treated in plaster for 6–8 weeks, followed by splinting for 4–6 weeks and hand physiotherapy. All the patients were analysed at the final follow-up using DASH score and x-rays. Mean age of the patients was 28 years (20–61) in 32 men and 3 women. We lost three patients (9%) to follow up. At a mean follow up of 16 weeks (12–18) twenty three patients (66%) achieved radiological union. All patients but three (91%) achieved good functional outcome at mean follow up of 14 weeks (10–16). A good functional outcome can be achieved with surgical fixation and bone graft in proximal pole scaphoid fractures non-union. Pre-operative fragmentation of proximal pole dictates type of fixation (screw or k wire or no fixation). There was no difference in outcome whether graft was harvested from distal radius or iliac crest


Orthopaedic Proceedings
Vol. 102-B, Issue SUPP_7 | Pages 94 - 94
1 Jul 2020
Undurraga S Au K Salimian A Gammon B
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Longstanding un-united scaphoid fractures or scapholunate insufficiency can progress to degenerative wrist osteoarthritis (termed scaphoid non-union advanced collapse (SNAC) or scapho-lunate advanced collapse (SLAC) respectively). Scaphoid excision and partial wrist fusion is a well-established procedure for the surgical treatment of this condition. In this study we present a novel technique and mid-term results, where fusion is reserved for the luno-capitate and triquetro-hamate joints, commonly referred to as bicolumnar fusion. The purpose of this study was to report functional and radiological outcomes in a series of patients who underwent this surgical technique. This was a prospective study of 23 consecutive patients (25 wrists) who underwent a bicolumnar carpal fusion from January 2014 to January 2017 due to a stage 2 or 3 SNAC/SLAC wrist, with a minimum follow-up of one year. In all cases two retrograde cannulated headless compression screws were used for inter-carpal fixation. The clinical assessment consisted of range of motion, grip and pinch strength that were compared with the unaffected contralateral side where possible. Patient-reported outcome measures, including the DASH and PRWE scores were analysed. The radiographic assessment parameters consisted of fusion state and the appearance of the radio-lunate joint space. We also examined the relationship between the capito-lunate fusion angle and wrist range of motion, comparing wrists fused with a capito-lunate angle greater than 20° of extension with wrists fused in a neutral position. The average follow-up was 2.9 years. The mean wrist extension was 41°, flexion 36° and radial-ulnar deviation arc was 43° (70%, 52% and 63% of contralateral side respectively). Grip strength was 40 kg and pinch strength was 8.9 kg, both 93% of contralateral side. Residual pain for activities of daily living was 1.4 (VAS). The mean DASH and PRWE scores were 19±16 and 29±18 respectively. There were three cases of non-union (fusion rate of 88%). Two wrists were converted to total wrist arthroplasty and one partial fusion was revised and healed successfully. Patients with an extended capito-lunate fusion angle trended toward more wrist extension but this did not reach statistical significance (P= 0.07). Wrist flexion did not differ between groups. Radio-lunate joint space narrowing progressed in 2 patients but did not affect their functional outcome. After bicolumnar carpal fusion using retrograde headless screws, patients in this series maintained a functional flexion-extension arc of motion, with grip-pinch strength that was close to normal. These functional outcomes and fusion rates were comparable with standard 4-corner fusion technique. A capito-lunate fusion angle greater than 20° may provide more wrist extension but further investigation is required to establish this effect. This technique has the advantage that compression screws are placed in a retrograde fashion, which does not violate the proximal articular surface of the lunate, preserving the residual load-bearing articulation. Moreover, the hardware is completely contained, with no revision surgery for hardware removal required in this series


Orthopaedic Proceedings
Vol. 94-B, Issue SUPP_II | Pages 98 - 98
1 Feb 2012
Kamineni S Lee R Sharma A Ankem H
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Radial head fractures with fragment displacement should be reduced and fixed, when classified as Mason II type injuries. We describe a method of arthroscopic fixation which is performed as a day case trauma surgery, and compare the results with a more traditional fixation approach, in a case controlled manner. We prospectively reviewed six Mason II radial head fractures which were treated using an arthroscopic reduction and fixation technique. The technique allows the fracture to be mobilised, reduced, and anatomically fixed using headless screws. All arthroscopic surgeries were conducted as day-cases. We retrospectively collected age and sex matched cases of open reduction and fixation of Mason II fractures using headless screws. The arthroscopic cases required less analgesia, shorter hospital admissions, and had fewer complications. The averaged final range of follow-up, at 1 year post-operation was 15 to 140 degrees in the arthroscopic group and 35 to 120 degrees in the open group. The Mayo Elbow Performance Score was 95/100 and 90/100 respectively. No acute complications were noted in the arthroscopic group, and a radial nerve neuropraxia [n=1], superficial wound infection [n=1], and loose screw [n=1]. Two patients of the arthroscopic group required secondary motion gaining operations [n=1 arthroscopic anterior capsulectomy for a fixed flexion contracture of 35 degrees, and n=1 loss of supination requiring and arthroscopic radial scar excision]. Three patients in the open group required secondary surgery [n=2 arthroscopic anterior capsulectomy for fixed flexion deformities, and n=1 arthroscopic anterior capsulectomy for fixed flexion deformities, and n=1 arthroscopic radial head excision for prominent screws, loss of forearm rotation, and radiocapitellar arthrosis pain]. The technique of arthroscopic fixation of Mason II radial head fractures appears to be valid, with respect to anatomical restoration of the fracture, minimal hospital admission, reduction in analgesia requirement, fewer complications, and a decreased need for secondary surgery


Orthopaedic Proceedings
Vol. 105-B, Issue SUPP_2 | Pages 110 - 110
10 Feb 2023
Kim K Wang A Coomarasamy C Foster M
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Distal interphalangeal joint (DIPJ) fusion using a k-wire has been the gold standard treatment for DIPJ arthritis. Recent studies have shown similar patient outcomes with the headless compression screws (HCS), however there has been no cost analysis to compare the two. Therefore, this study aims to 1) review the cost of DIPJ fusion between k-wire and HCS 2) compare functional outcome and patient satisfaction between the two groups. A retrospective review was performed over a nine-year period from 2012-2021 in Counties Manukau. Cost analysis was performed between patients who underwent DIPJ fusion with either HCS or k-wire. Costs included were surgical cost, repeat operations and follow-up clinic costs. The difference in pre-operative and post-operative functional and pain scores were also compared using the patient rate wrist/hand evaluation (PRWHE). Of the 85 eligible patients, 49 underwent fusion with k-wires and 36 had HCS. The overall cost was significantly lower in the HCS group which was 6554 New Zealand Dollars (NZD), whereas this was 10408 NZD in the k-wire group (p<0.0001). The adjusted relative risk of 1.3 indicate that the cost of k-wires is 1.3 times more than HCS (P=0.0053). The patients’ post-operative PRWHE pain (−22 vs −18, p<0.0001) and functional scores (−38 vs −36, p<0.0001) improved significantly in HCS group compared to the k-wire group. Literatures have shown similar DIPJ fusion outcomes between k-wire and HCS. K-wires often need to be removed post-operatively due to the metalware irritation. This leads to more surgical procedures and clinic follow-ups, which overall increases the cost of DIPJ fusion with k-wires. DIPJ fusion with HCS is a more cost-effective with a lower surgical and follow-up costs compared to the k-wiring technique. Patients with HCS also tend to have a significant improvement in post-operative pain and functional scores


Orthopaedic Proceedings
Vol. 98-B, Issue SUPP_5 | Pages 21 - 21
1 Feb 2016
Volk I Gal J Peleg E Almog G Luria S
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Introduction. Scaphoid fractures are commonly treated with a single headless screw. There are different recommendations regarding the optimal location of this screw. The purpose of this study was to compare the location of screws placed for the treatment of acute scaphoid fractures with theoretical and virtual screw locations. Materials and Methods. 10 patients with acute scaphoid fractures treated surgically and with available pre- and postoperative CT scans were included. The scans were analysed using a 3D software model (Amira Dev 5.3, Mercury Computer Systems, Chelmsford, MA). On the preoperative CTs the displaced fractures were virtually reduced. Possible screw locations for fracture fixation were examined including one along the central third of the proximal fragment (central base screw), the scaphoid longitudinal axis calculated mathematically (PCA screw) and a screw placed perpendicular to the fracture plane (90 degree screw). The angle between the axes and fracture plains were measured. The angle and distance between the actual screw on the postoperative CT and the different virtual screw locations were measured as well. Results. The angles between the actual and virtual screws to the fracture plane were between a mean of 67 to 69 degrees. The angle between the axes was greatest between the 90 degree screws to the PCA and actual screws (mean 23 degrees both; p=0.034) and smallest between the central base screws and PCA to the actual screws (mean of 12.1 and 12.5 degrees, respectively; p=0.034). The difference between the entrance and exit points between the axes was between 3.1 to 4.8 mm other than the 90 degree screws which were 5.3 to 7.1 mm to the other axes (p=0.002). The PCA (mean 28.3 mm) were found to be longer than the actual screws (mean 25.4) or the 90 degree screws (mean 23.5) (p=0.034 and p=0.008 respectively). The 90 degree screws were shorter than the PCA or central base screws (p=0.008, p=0.034 respectively), but not the actual screws. Discussion. There were no significant differences in the angles between actual and virtual optimal screws other than the 90 degree screws. The PCA was found to be the longest screw and at a similar angle to the fractures as the other virtual screw options, other than the shorter 90 degree screw. Virtual reduction and preplanning of the screw location, using standard software, may enable the surgeon to place the longest screw along the PCA longitudinal axis. If placing a 90 degree screw is considered, this may be technically difficult or may necessitate a trans-trapezial approach


Orthopaedic Proceedings
Vol. 94-B, Issue SUPP_XXXIV | Pages 34 - 34
1 Jul 2012
Modi C Hill C Saithna A Wainwright D
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Trans-articular coronal shear fractures of the distal humerus pose a significant challenge to the surgeon in obtaining an anatomical reduction and rigid fixation and thereby return of good function. A variety of approaches have been described which include the extended lateral and anterolateral approaches and arthroscopically-assisted fixation for non-comminuted fractures. Fixation methods include open or percutaneous cannulated screws and headless compression screws directed either anterior to posterior or posterior to anterior. We describe an illustrated, novel approach to this fracture which is minimally invasive but enables an anatomical reduction to be achieved. A 15 year old male presented with a Bryan and Morrey type 4 fracture as described by McKee involving the left distal humerus. He was placed in a lateral position with the elbow over a support. A posterior longitudinal incision and a 6cm triceps split from the tip of the olecranon was made. The olecranon fossa was exposed and a fenestration made with a 2.5mm drill and nibblers as in the OK (Outerbridge-Kashiwagi) procedure. A bone lever was then passed though the fenestration and used to reduce the capitellar and trochlear fracture fragments into an anatomical position with use of an image intensifier to confirm reduction. The fracture was then fixed with two headless compression screws from posterior to anterior into the capitellar and trochlear fragments (see images). Early mobilisation and rehabilitation were commenced. Follow-up clinical examination and radiographs at six weeks revealed excellent range-of-motion and function with anatomical bony union. We believe that this novel approach to this fracture reduces the amount of soft tissue dissection associated with conventional approaches and their associated risks and also enables earlier return to function with restoration of anatomy


Orthopaedic Proceedings
Vol. 95-B, Issue SUPP_14 | Pages 9 - 9
1 Mar 2013
Zinn R Carides M
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Aim. Distal interphalangeal joint (DIPJ) arthrodesis is a well-accepted treatment of disease in the DIPJ of the hand. The ideal technique should be technically simple, quick, cheap, have minimal complications and yield a rapid return to function. Recent large published series report major complications of 11.1% and minor complications of 26% for this procedure. The study objective is to determine patient satisfaction and complication rates of DIPJ fusion using the Autofix screw (Small Bone Innovations, France), a smaller diameter headless compression screw. Methods. A standard questionnaire was devised to assess patients' overall satisfaction and complications related to the procedure. This data is compared to equivalent procedures published internationally. The patient's radiological records were reviewed to determine bone union at 7 weeks post-operation. Results. 39 fingers were fused in 29 participants. Mean follow up was 36 months (range 2–48 months). Patient satisfaction was above 90%. We had a major complication rate of 2.56%, a minor complication rate of 20.5%. There was a higher rate of complications in patients younger than 60 years of age. Discussion. Our technique for the insertion of the Autofix, headless compression screw is shown. It is a simple, quick and effective technique for the fusion of distal interphalangeal joints of all fingers; there is no ‘down-time’, and complication rates are superior to the largest series published in international literature. Furthermore, we demonstrated 100% union by 7 weeks in our patient sample. We attribute these results to 3 aspects of the procedure. 1) The Autofix screw is a smaller diameter screw than previously used for this procedure. 2) The screw generates significant compression across the fusion site. 3) We utilise bone graft as part of our routine management. NO DISCLOSURES


Orthopaedic Proceedings
Vol. 94-B, Issue SUPP_XXXIX | Pages 119 - 119
1 Sep 2012
Al-Nammari S Al-Hadithy N
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Introduction. Isolated trochlea fractures are very rare and have only been described previously as case reports. Aims. To report on a case of isolated trochlea fracture and to present a review of the literature. Results. There have only been four previous reports of isolated trochlea fracture. Our fifth case is included in the analysis of the literature given below. Average age 26 (Range 12–33). 60% female, 80% left sided. Dominance only stated in 40% of cases- 50% dominant side. Mechanism of injury: 60% low velocity fall onto an outstretched hand, 40% high velocity- RTA & fall off horse- exact mechanism of injury unknown. Patients all presented with elbow held in flexion, pain and swelling over the medial aspect and a painfully reduced range of motion. Diagnosis made on plain radiographs in 80%, tomograms required in 20%. AP noted to be essential to differentiate from more common capitellum fracture. 20% of fractures associated with comminution. Management consisted of open reduction through a medial approach and internal fixation in 80% (20% headless screw, 20% k-wire, 40% 4.0mm partially threaded cancellous screws) and olecranon traction in 20%. Elbows were immobilised from 3 to 8 weeks. Time to union ranged from 6 weeks (80%) to 13 weeks (20%). Outcomes were uniformly excellent with 40% being asymptomatic with a FROM, 20% asymptomatic with 10 degrees loss of extension and 40% asymptomatic with 5–20 degrees loss of flexion. There were no reported complications. Conclusion. These are rare injuries and can occur through high and low energy mechanisms. They tend to occur in younger age groups. Diagnosis can be made readily with plain radiographs- the AP is essential in differentiating it from the more common capitellum fracture. The prognosis for this intra-articular fracture is good to excellent


Orthopaedic Proceedings
Vol. 94-B, Issue SUPP_XLI | Pages 92 - 92
1 Sep 2012
Bertollo N Crook T Hope B Scougall P Lunz D Walsh W
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Shape memory staples have several uses in both hand and foot and ankle surgery. There is relatively little data available regarding the biomechanical properties of staples, in terms of both the compression achieved and potential decay of mechanical advantage with time. An understanding of these properties is therefore important for the surgeon. Two blocks of synthetic polyurethane mimicking properties of cancellous bone were fixed in jigs to both the actuator and 6 degree-of-freedom load cell of an MTS servohydraulic testing machine. With the displacement between the blocks held constant the peak value and subsequent decay in compressive force applied by both the smooth and barbed version of the nitinol OSStaple (Biomedical Enterprises), Easyclip (LMT), Herbert Bone Screws (Martin) and the Headless Compression Screw (Synthes) was measured. Nitinol staples were energised once only. A second experiment was conducted to assess the effects of repeated energisation on these parameters. The Easyclip staples achieved a mean peak force of 5.2N, whilst the smooth and barbed OSStaples achieved values of 9.3N and 5.7N, respectively. The Herbert screws achieved a mean peak force of 9N and the headless compression screws 23.9N. The mean peak force achieved with 2 Easyclip staples in parallel was 8.1N. Following the application of a single energisation the OSStaples exhibited a significant reduction in compressive load, losing up to approximately 70% of the peak value attained. The repeated energisation of these nitinol staples produced progressive increases in both peak and trough loads, the positive effects exhibited a plateau with time. Performance of both OSStaples was comparable to the Herbert screw with regard to reduction load applied across a simulated fracture plane. The maximum load applied by the OSStaples diminished with time. Staples provide fixation without violating the fracture plane which has the potential to offer some benefits from a healing perspective


Orthopaedic Proceedings
Vol. 94-B, Issue SUPP_XXIII | Pages 78 - 78
1 May 2012
Esser M Russ M Hamilton S Liew S
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Osteochondral fracture of the femoral head is an uncommon injury with a high potential for a poor functional outcome. Management is often challenging with limited options. We present two cases in which osteochondral fractures of the femoral head were treated with partial resurfacing using the HemiCAP System (Arthrosuface, Franklin MA, USA). Patient 1. A 22-year-old male professional motorbike rider presented with an anterior left hip dislocation that occurred during a race. A CT scan after a closed reduction revealed a large osteochondral impaction fracture/defect that was addressed via partial resurfacing using the HemiCAP System. Patient 2. A 34-year-old male presented with an anterior left hip dislocation after a motor vehicle accident and underwent a closed reduction. CT showed a loose osteochondral fragment, that was fixed back with headless screws, and an adjacent defect was addressed with a HemiCAP implant. Both patients were kept non weight-bearing for two months and had an uneventful recovery. Patient 1 was last reviewed at our institution one month post-operatively with a pain-free hip. His follow-up is being continued interstate and at telephone interview, 18 months after surgery, he had returned to full function and resumed riding on the professional racing circuit. Patient 2, at three-month review, had a pain-free hip with a full range of motion. CT scan showed excellent joint surface congruity at the implant articular surface junction. We report the use of the HemiCAP System as a novel method of treating osteochondral defects, which has never been reported before. There has only been one other reported case of using a HemiCAP in an osteoarthritic femoral head. This is a short follow-up with only two patients treated; however we are encouraged by the results so far, as there are no other satisfactory alternative treatment options


Orthopaedic Proceedings
Vol. 96-B, Issue SUPP_19 | Pages 19 - 19
1 Dec 2014
Carides E
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Introduction and Aims:. The surgical treatment of fractures of the scaphoid with delayed presentation or with established non-union pose a formidable challenge with reported failure rates between 15% and 45%. The aim of this study is to report the results of percutaneous versus open fixation with bone grafting of these fractures. Method:. 34 Consecutive patients who underwent surgery between 2009 and 2013 for delayed presentation and established non-union of scaphoid fractures have been reviewed retrospectively. There were 27 males and 7 females with a mean age of 31 years (15 to 66). The mean delay from time of injury to operation was 12 weeks (4 weeks to 11 months) in the percutaneous fixation group and 19 months (5 months to 6 years) in the open fixation group. 19 Patients were treated with percutaneous screw fixation alone and 15 patients underwent open reduction and internal fixation supplemented with autogenous corticocancellous iliac bone graft. The classification of Slade and Dodds (2009) was used as a guide for surgical treatment and the Mini-Acutrak headless compression screw was used as the fixation device in all cases. Results:. Patients underwent final clinical and radiological assessment with plain radiographs 6 months following their surgery. There was one failed union in the percutaneous fixation group and there was one failed union in the open fixation group. One patient in the open fixation group was lost to follow up. No serious complications were recorded in either group. Conclusion:. The success of percutaneous internal fixation for acute fractures of the carpal scaphoid may be extended to include scaphoid fractures with delayed presentation and fractures of the scaphoid with established nonunion. However, appropriate patient selection is necessary to ensure optimal outcomes


Orthopaedic Proceedings
Vol. 98-B, Issue SUPP_9 | Pages 49 - 49
1 May 2016
Mohammed A
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Background. External fixation for a fracture-dislocation to a joint like the elbow, while maintaining joint mobility is currently done after identifying the center of rotation under X-ray guidance, when applying either a mono-lateral or a circular fixator. Current treatment. using the galaxy fixation system by Orthofix, the surgeon needs to correctly identify the center of rotation of the elbow under X-ray guidance on lateral views. If the center of rotation of the fixator is not aligned with that of the elbow joint, the assembly will not work, i.e. the elbow will be disrupted on trying to achieve flexion or extension movements. Figures (A, B, C and D) summarize the critical steps in identifying the centre of rotation (Courtesy of Orthofix Orthopedics International). New design. This new idea aims to propagate the principle of sliding external fixation applied on the extensor side of a joint, with the limbs of the fixator being able to slide in and out during joint extension and flexion respectively, without hindering the joint movement. Taking the ulno-humeral joint as an example, it is enough to apply the sliding external fixator in line with the subcutaneous border of the ulna, and the pins in the sagital plane, without the need to use x-ray guidance to identify the center of rotation, which simplifies the procedure, and makes it less technically demanding. The sliding external fixator over the elbow involves two bars which accommodate half pins fixation with headless grip screws to hold the pins, identical to the Rancho cubes technique by Smith & Nephew, these slide snugly into sleeves, those sleeves linked together through a hinge behind the elbow, and the bars are spring loaded to the hinge through the inside of the sleeves, which means they will slid into the sleeves in extension and out in flexion. Length of the sleeve should prevent the bars from dislodgement, and the cross section of both the bars and the sleeves have to correspond to each other for the sleeves to accommodate the bars within them and to prevent rotational instability within the construct itself. Summary. Applying an external fixator on the extensor surface is an idea could lead to major changes in external fixation product design, the ulno-humeral joint is taken as an example, and other joints could also be addressed taking in consideration joint size and anatomical structures at risk. The sliding technique makes the application easier, without the need to X-ray guided identification of the center of rotation


Orthopaedic Proceedings
Vol. 94-B, Issue SUPP_III | Pages 80 - 80
1 Feb 2012
Wharton R Kuiper J Kelly C
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Objective. To compare the ability of a new composite bio-absorbable screw and two conventional metal screws to maintain fixation of scaphoid waist-fractures under dynamic loading conditions. Methods. Fifteen porcine radial carpi, with morphology comparable to human scaphoids, were osteotomised at the waist. Specimens were randomised in three groups: Group I were fixed with a headed metal screw, group II with a headless tapered metal screw and group III with a bio-absorbable composite screw. Each specimen was oriented at 45° and cyclically loaded using four blocks of 1000 cycles, with peak loads of 40, 60 (normal load), 80 and 100 N (severe load) respectively. Permanent displacement and translation (step-off) at the fracture site was measured after each loading block from a standardised high-magnification photograph using image analysis software (Roman v1.70, Institute of Orthopaedics, Oswestry). Statistical analysis was by ANOVA and tolerance limits. Results. No gross failure or fracture gap displacement occurred. Average translations (step-off) at the fracture site after 4000 cycles up to 100N were 0.05mm±0.02SD (headed metal), 0.14mm±0.14SD (headless metal) and 0.29mm±0.11SD (composite) and differed significantly (p<0.01). Using tolerance limits, the data allowed us to predict that, with 95% certainty, the maximum average translation (step-off) following severe loading in 95% of any sample fixed with a headed metal screw will be below 0.17mm, headless metal screw below 0.74mm, and composite screw below 0.76mm. Conclusion. We observed only small average translations (step-off) for all three screws. Moreover, translations of more than 1mm that would predispose to non-union were highly unlikely for any of the screws, even after severe cyclic loading. We therefore conclude that a new bio-absorbable composite screw can serve as an alternative to conventional screws when fixing scaphoid fractures


Orthopaedic Proceedings
Vol. 95-B, Issue SUPP_28 | Pages 85 - 85
1 Aug 2013
Khamaisy S Peleg E Segal G Hamad A Luria S
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Purpose. The surgical treatment of scaphoid fractures consists of reduction of the fracture followed by stable internal fixation using a headless compression screw. Proper positioning of the screw remains technically challenging and therefore computer assisted surgery may have an advantage. Navigation assisted surgery requires placement and registration of stable reference markers which is technically impossible in a small bone like the scaphoid. Custom made wrist-positioning devices with built-in reference markers have been developed for this purpose. The purpose of this study was to evaluate a different method of navigation assisted scaphoid fracture fixation. Temporary stabilisation with a pin of the scaphoid to the radius enables placement of the reference markers on the radius. Our hypothesis was that this method will achieve precise fracture fixation, superior to the standard free hand technique. Methods. In 20 identical saw bone models with mobile scaphoids, the scaphoid was stabilised to the radius using one Kirschner wire (KW). An additional KW representing the fixating screw was placed either using the Mazor Renaissance Robotic System (MAZOR Surgical Technologies, Israel) or standard free hand technique. CT scans were performed prior to fixation and after fixation in order to plan the location of the KW and compare this planned location with the final result. Results. No significant difference was found between the measures of KW location between groups and in comparison with the planned location, including entry and exit points of the KW, length of KW through the scaphoid (mean axis length of 28.7 mm [SD 1.5] with the robot system versus 29.6 mm [SD 2.1] with the free hand technique) and difference in angle of fixation with the planned axis of fixation (mean of 1.7 degrees [SD 5.5] with the robot versus 3.8 degrees [SD 5.6] free hand). Significant differences were found between exposure to radiation (mean of 0.07 Rad [SD 0.04] with the robot system versus 13.9 Rad [SD 18.4] with the free hand technique; p=0.04) and the number of attempts in placing the KW (mean of 1.1 attempts [SD 0.32] with the robot versus 8 attempts [SD 6.65] free hand; p=0.01). Conclusion. Computer assisted fixation of a scaphoid fracture was found to be as accurate as the free hand technique, after fixation of the scaphoid to the radius, without the need for a custom splint. It was also shown to be superior by decreasing the exposure to radiation and number of attempts of KW placement