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Bone & Joint Research
Vol. 6, Issue 4 | Pages 216 - 223
1 Apr 2017
Ang BFH Chen JY Yew AKS Chua SK Chou SM Chia SL Koh JSB Howe TS

Objectives. External fixators are the traditional fixation method of choice for contaminated open fractures. However, patient acceptance is low due to the high profile and therefore physical burden of the constructs. An externalised locking compression plate is a low profile alternative. However, the biomechanical differences have not been assessed. The objective of this study was to evaluate the axial and torsional stiffness of the externalised titanium locking compression plate (ET-LCP), the externalised stainless steel locking compression plate (ESS-LCP) and the unilateral external fixator (UEF). Methods. A fracture gap model was created to simulate comminuted mid-shaft tibia fractures using synthetic composite bones. Fifteen constructs were stabilised with ET-LCP, ESS-LCP or UEF (five constructs each). The constructs were loaded under both axial and torsional directions to determine construct stiffness. Results. The mean axial stiffness was very similar for UEF (528 N/mm) and ESS-LCP (525 N/mm), while it was slightly lower for ET-LCP (469 N/mm). One-way analysis of variance (ANOVA) testing in all three groups demonstrated no significant difference (F(2,12) = 2.057, p = 0.171). There was a significant difference in mean torsional stiffness between the UEF (0.512 Nm/degree), the ESS-LCP (0.686 Nm/degree) and the ET-LCP (0.639 Nm/degree), as determined by one-way ANOVA (F(2,12) = 6.204, p = 0.014). A Tukey post hoc test revealed that the torsional stiffness of the ESS-LCP was statistically higher than that of the UEF by 0.174 Nm/degree (p = 0.013). No catastrophic failures were observed. Conclusion. Using the LCP as an external fixator may provide a viable and attractive alternative to the traditional UEF as its lower profile makes it more acceptable to patients, while not compromising on axial and torsional stiffness. Cite this article: B. F. H. Ang, J. Y. Chen, A. K. S. Yew, S. K. Chua, S. M. Chou, S. L. Chia, J. S. B. Koh, T. S. Howe. Externalised locking compression plate as an alternative to the unilateral external fixator: a biomechanical comparative study of axial and torsional stiffness. Bone Joint Res 2017;6:216–223. DOI: 10.1302/2046-3758.64.2000470


Orthopaedic Proceedings
Vol. 88-B, Issue SUPP_II | Pages 323 - 323
1 May 2006
Faraj S Theis J
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Locking compression plate is part of a new plate generation requiring an adapted surgical technique and new thinking about commonly used concepts of internal fixation using plates. They offer a number of advantages in fracture fixation combining angular stability through the use of locking screws with traditional fixation techniques. This makes the implant suitable for poor bone stock and for fractures in metaphyseal areas. However the system is complex and cases of plate loosening and plate breakage reported by many authors recently, many of these authors believe it is attributed to the choice of inappropriate plate and/or fixation technique rather than to the features of locking compression plate system. We are reporting 2 cases of plate breakage after using it to fix diaphyseal femoral shaft fractures; in each case we discuss the pitfalls in the fixation method. The locking plate manual did not highlight the important pitfalls, which was published later on in the literature as guidelines for their clinical application. Careful and detailed attention to the biomechanical principles of locking compression is crucial to the success of implant in fixing fractures in diaphyseal areas


Arthrodesis of the first metatarsophalangeal joint (MTPJ) is the most reliable surgical option, for hallux rigidus from end-stage osteoarthritis. The aim of the study was to compare the functional outcomes of memory nickel-titanium staples versus a compression plate with a cross screw construct for first MTPJ arthrodesis using the Manchester–Oxford Foot Questionnaire (MOXFQ). Patients who underwent MTPJ arthrodesis using either memory nickel-titanium staples or a compression plate with a cross screw construct were identified from the surgical lists of two orthopaedic consultants. Pre and post-operative MOXFQ questionnaire, a validated patient-reported outcome measure, was administered, and responses were analysed to derive the MOXFQ summary index. The study included 38 patients (staple group N=12 and plate and cross screw group N=26). 23 patients were female and 15 were male. Mean age was 64.8 years (SD 9.02; 40 to 82). Initial analysis showed no significant difference in preoperative MOXFQ scores between the groups (p = 0.04). Postoperatively, the staple group exhibited a mean improvement of 36.17, surpassing the plate group's mean improvement of 23. Paired t-test analysis revealed a statistically significant difference (t-score= 2.5, p = 0.008), favouring the use of staples. The findings indicate that the use of staples in MTPJ arthrodesis resulted in a significantly greater improvement in MOXFQ scores compared to plates. Further research is needed to explore the underlying factors contributing to this difference and to evaluate long-term effects on patient outcomes


The Journal of Bone & Joint Surgery British Volume
Vol. 88-B, Issue 12 | Pages 1610 - 1612
1 Dec 2006
Al-Rashid M Theivendran K Craigen MAC

The use of volar locking compression plates for the treatment of fractures of the distal radius is becoming increasingly popular because of the stable biomechanical construct, less soft-tissue disturbance and early mobilisation of the wrist. A few studies have reported complications such as rupture of flexor tendons. We describe three cases of rupture of extensor tendons after the use of volar locking compression plates. We recommend extreme care when drilling and placing the distal radial screws to prevent damaging the extensor tendons


The Journal of Bone & Joint Surgery British Volume
Vol. 77-B, Issue 5 | Pages 700 - 704
1 Sep 1995
O'Bierne J Boyer M Axelrod T

We performed 45 wrist arthrodeses in 43 patients by a modification of the AO technique using the dynamic compression plate. Radiological follow-up was obtained in 41 wrists; all had united at a mean of ten weeks. Clinical follow-up was obtained in 32 wrists. Subjectively, the surgical outcome was satisfactory in 26, marginally satisfactory in two and unsatisfactory in four. This method is safe and reliable. The plate can be contoured to allow a variety of positions of fusion, and gives rigid immobilisation. The rate of union is higher than that for other techniques


Orthopaedic Proceedings
Vol. 94-B, Issue SUPP_XXXVII | Pages 437 - 437
1 Sep 2012
Kobbe P Hockertz I Sellei R Reilmann H Hockertz T
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Sacroiliac screw fixation is the method of choice for the definitive treatment of unstable posterior pelvic ring injuries; however this technique is demanding and associated with a high risk of iatrogenic neurovascular damage. We therefore evaluated the outcome, complications, surgical and fluoroscopy time for unstable posterior pelvic ring injuries managed with a transiliac locked compression plate. 23 patients were managed with a transiliac locked compression plate for unstable posterior pelvic injuries at a Level I Trauma Center. 21 patients were available for follow up after an average of 30 months and outcome evaluation was performed with the Pelvic Outcome Score, which is composed of a clinical, radiological, and social integration part. The overall outcome for the pelvic outcome score was excellent in 47.6% (10 patients), good in 19% (4 patients), fair in 28.6% (6 patients) and poor in 4.8% (1 patient). 15 out of 21 patients (71.4%) returned to their normal life, 3 patients (14.3%) were limited at work, and 3 patients (14.3%) were not able to return to work due to their disabilities. The social status was unchanged to the preinjury status in 19 patients (90.5%). 13 patients (62%) stated no changes in spare time and sports activities; 4 patients (19%) had minor and another 4 patients (19%) had major restrictions. The average operation time was 101 min and intraoperative fluoroscopic time averaged 74.2 sec. No iatrogenic neurovascular injuries were observed. Posterior percutaneous plate osteosynthesis may be a good alternative to sacral screw fixation because it is quick, safe, and associated with a good functional outcome


Orthopaedic Proceedings
Vol. 85-B, Issue SUPP_I | Pages 47 - 47
1 Jan 2003
Ramamohan N Gross M
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Numerous techniques of arthrodesis of the ankle have been described in the literature with variable results. Although arthrodesis achieves satisfying results in most cases, high complication rates have been reported. We utilized a medial compression T plate to achieve fusion and the aim of this study is to present the early to mid term results of this procedure at our institution. 20 patients (23 ankles) underwent ankle arthrodesis by a single surgeon using the same surgical technique. Under tourniquet control, a medial longitudinal incision centering on the medial malleolus was used. After osteotomising the medial malleolus to expose the ankle joint, chevron cuts were made in the tibia and the talus removing only enough bone. The cut surfaces are apposed and then compressed together by using a medial compression T plate. The excised medial malleolus was used as bone graft. The fixation was protected in a plaster cast and allowed only partial weight bearing for up to 10 weeks. The ankles were clinically assessed by Mazur ankle scoring system and radiologically assessed until fusion was solid. The mean age at operation was 56 years (range 20–76) and the sex distribution was equal. Indication for surgery included either posttraumatic or rheumatoid arthritis. At a mean follow-up of 73 months (range 6–112), all the patients had complete pain relief. Complications included deep infection in two ankles (Rheumatoid patient, needed implant removal), subtalar pain in four and nonunion in one ankle. There was late loss of position in 2 ankles (same patient), who was later diagnosed with charcot’s joints. All the fusions occurred within 16 weeks. The fusion rate with this technique was 96% with the medial T plate providing a stable internal fixation. Our experience suggests that medial compression arthrodesis of the ankle is a reliable and an easily reproducible technique with a very low incidence of complications


Orthopaedic Proceedings
Vol. 87-B, Issue SUPP_II | Pages 183 - 183
1 Apr 2005
Giancola R Crippa C
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Percutaneous compression plates (PCCP) used in the treatment pertrochanteric fractures are made of stainless steel, available in one size only and have two threaded oblique proximal holes for the telescopic cephalic (femoral neck) screws and three distal holes for the shaft self-tapping screws. The plate is inserted at right angles to the femoral diaphysis through a small incision and rotated so that its axis is parallel to the diaphysis. By means of small movements it is advanced along the bone, positioned between the vastus lateralis muscle and the periosteum and then fixed with the proximal and distal screws. The neck screws are telescopic and they provide a double axis fixation in the femoral neck, which increases rotational stability by allowing fracture compression and preventing collapse of the neck and subsequent cut-out. Surgery takes about 30 min and consists of two small longitudinal incisions; thus the procedure is associated with only minimal blood loss. From March 2003 to May 2004 we treated 101 patients with PCCP: 73 women and 28 men with an average age of 82 years (range 26–101 years). The average blood loss was 92.4 ml. Of the patients, 31 (29.8%) did not receive blood transfusions and of the remaining 70 patients (70.2%), 26 received one unit of blood, 35 two units and nine two units operatively and two post-operatively. When possible, weight-bearing was allowed on the third postoperative day, thus achieving a functional recovery. The healing times are similar to those of other methods. No incidence of fracture collapse or screw cut-outs was seen in this series


The Journal of Bone & Joint Surgery British Volume
Vol. 82-B, Issue 3 | Pages 336 - 339
1 Apr 2000
McCormack RG Brien D Buckley RE McKee MD Powell J Schemitsch EH

We randomised prospectively 44 patients with fractures of the shaft of the humerus to open reduction and internal fixation by either an intramedullary nail (IMN) or a dynamic compression plate (DCP). Patients were followed up for a minimum of six months. There were no significant differences in the function of the shoulder and elbow, as determined by the American Shoulder and Elbow Surgeons’ score, the visual analogue pain score, range of movement, or the time taken to return to normal activity. There was a single case of shoulder impingement in the DCP group and six in the IMN group. Of these six, five occurred after antegrade insertion of an IMN. In the DCP group three patients developed complications, compared with 13 in the IMN group. We had to perform secondary surgery on seven patients in the IMN group, but on only one in the DCP group (p = 0.016). Our findings suggest that open reduction and internal fixation with a DCP remains the best treatment for unstable fractures of the shaft of the humerus. Fixation by IMN may be indicated for specific situations, but is technically more demanding and has a higher rate of complications


The Journal of Bone & Joint Surgery British Volume
Vol. 89-B, Issue 9 | Pages 1210 - 1217
1 Sep 2007
Peyser A Weil YA Brocke L Sela Y Mosheiff R Mattan Y Manor O Liebergall M

Limited access surgery is thought to reduce post-operative morbidity and provide faster recovery of function. The percutaneous compression plate (PCCP) is a recently introduced device for the fixation of intertrochanteric fractures with minimal exposure. It has several potential mechanical advantages over the conventional compression hip screw (CHS). Our aim in this prospective, randomised, controlled study was to compare the outcome of patients operated on using these two devices. We randomised 104 patients with intertrochanteric fractures (AO/OTA 31.A1–A2) to surgical treatment with either the PCCP or CHS and followed them for one year postoperatively. The mean operating blood loss was 161.0 ml (8 to 450) in the PCCP group and 374.0 ml (11 to 980) in the CHS group (Student’s t-test, p < 0.0001). The pain score and ability to bear weight were significantly better in the PCCP group at six weeks post-operatively. Analysis of the radiographs in a proportion of the patients revealed a reduced amount of medial displacement in the PCCP group (two patients, 4%) compared with the CHS group (10 patients, 18.9%); Fisher’s exact test, p < 0.02. The PCCP device was associated with reduced intra-operative blood loss, less postoperative pain and a reduced incidence of collapse of the fracture


Orthopaedic Proceedings
Vol. 100-B, Issue SUPP_15 | Pages 119 - 119
1 Nov 2018
Jalal M Wallace R Simpson H
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There is a growing trend towards using pre-clinical models of atrophic non-union. This study investigated different fixation devices, by comparing the mechanical stability at the fracture site of tibia bone fixed by either intramedullary nail, compression plate or external fixator. 40 tibias from adult male Wistar rats' cadavers were osteotomised at the mid-shaft and a gap of 1 mm was created and maintained at the fracture site to simulate criteria of atrophic non-union model. These were divided into five groups (n=8 in each): the first group was fixed with 20G intramedullary nail, the second group with 18G nail, the third group with 4-hole plate, the fourth group with 6-hole plate, and the fifth group with external fixator. Tibia was harvested by leg disarticulation from the knee and ankle joints, the soft tissues were carefully removed from the leg, and tibias were kept hydrated throughout the experiment. Each group was then subdivided into two subgroups for mechanical testing: one for axial loading (n=4) and one for 4-point bending (n=4). Statistical analysis was carried out by ANOVA with a fisher post-hoc comparison between groups. A p-value less than 0.05 was considered statistically significant. Axial load to failure data and stiffness data revealed that intramedullary nails are significantly stronger and stiffer than other devices, however there was no statistically significant difference axially between the nail thicknesses. In bending, load to failure revealed that 18G nails are significantly stronger than 20G. We concluded that 18G nail is superior to the other fixation devices, therefore it has been used for in-vivo experiments to create a novel model of atrophic non-union with stable fixation


Orthopaedic Proceedings
Vol. 94-B, Issue SUPP_XXXVII | Pages 501 - 501
1 Sep 2012
Bernhard S Schmidt-rohlfing B Pfeifer R Heussen N Pape H
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A wide variety of intra- and extramedullary devices for the treatment of trochanteric fractures has been described. The Percutaneous Compression Plate is a minimally invasive and extramedullary device, which requires two 2–2.5 cm long incisions with minimal dissection oft soft tissue on the lateral aspect of the proximal femur. Earlier studies indicated that internal fixation using the PCCP is associated with a decreased perioperative blood loss, reduced transfusion requirements, with less postoperative pain, more rapid mobilisation, and with a reduced incidence of collapse of the fracture when compared with the standard device Dynamic Hip Screw. Aim of this study is to analyze the risk factors for the occurrence of local complications after internal fixation of intertrochanteric fractures of the femur using a Percutaneous Compression Plate. In a retrospective cohort study patients with trochanteric fractures who underwent internal fixation with a PCCP were included. We investigated the potential risk factors age, gender, experience of the surgeon as indicated by the numbers of surgical procedures with the PCCP device, stability of the fracture according to the AO/OTA classification, and co-morbidities of the patients according to the ASA classification. The operations were performed by ten different surgeons. All local complications which required re-operation were recorded. They included cutting out of the screw, loosening of the screw barrels, local haematoma, and infections. Logistic regression analysis was carried out to determine the risk factors for local complications. The mean age of the 122 patients included in this study was 78.5 years. 87 patients were female (70.7 %), 36 patients were male (29.3 %). With respect to the stability of the fracture 64 trochanteric fractures (52.5%) were classified as stable according to the AO/OTA classification, whereas 58 (47.5%) were considered to be unstable. Of the total of 122 patients with 122 trochanteric fractures eleven underwent re-operation due to local complications (9 %). The most frequent complication was complete or imminent cutting out of the upper cervical screw (N=5; 4 %). In the multivariate logistic regression model the only statistically significant risk factor was the experience of the surgeon (p=0.0316; odds ratio=4.7; CI 1.1–19.4). Our data indicate that the experience of the surgeon is a significant risk factor for the occurrence of local complications. The frequent use of this device seems to lower the re-operation rate


Orthopaedic Proceedings
Vol. 87-B, Issue SUPP_III | Pages 379 - 379
1 Sep 2005
Weisbrot M Garti A Pirotzki A Yassin M Hendel D Robinson D
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Purpose: Numerous implants used in repairing a trochanteric fracture of the hip are currently available. The purpose of this prospective study was to determine the complications and results of the percutaneous compression plate (PCCP), a relatively new device versus the conventional dynamic hip screw (DHS). Materials and Methods: Between 2001–2003, 110 consecutive patients with trochanteric fractures were treated in our department. Fifty-five fractures were stabilized using the PCCP and 55 fractures were treated with the DHS. Results were analyzed according to fracture pattern, type of implant, quality of fracture reduction and position of implant. Function was assessed on the basis of pain, walking aids and walking capability. Results: Forty-seven (85%) of 55 hips treated with PCCP healed without additional treatment and complications. Forty-three (78%) treated with DHS healed without additional treatment and complications. Complications among 8 patients (15%) of the PCCP group were: deep vein thrombosis, cardiac complication, chest infection and pressure sores. Complications among 12 patients (22%) of the DHS group were: implant failure (7%), deep wound infection, deep vein thrombosis and pressure sores. Conclusions: Use of the PCCP implant provides similar and occasionally better results compared to those obtained with the conventional DHS device. The most outstanding advantage of the PCCP device was no implant failure or implant cut out


The Journal of Bone & Joint Surgery British Volume
Vol. 82-B, Issue 4 | Pages 566 - 570
1 May 2000
Anderson GA Thomas BP

Between June 1991 and May 1996 we carried out arthrodesis on 15 patients with flail or partially flail wrists using an AO/ASIF dynamic compression plate (DCP) without a bone graft. The wrist was approached through the second extensor compartment. The minimum follow-up was for 24 months with a mean of 34.2 months. All 15 wrists fused without major complications at a mean of 11.9 weeks. Stabilisation improved the function of the hand affected with paralysis and the appearance of the extensively paralysed upper limb with a flail hand. In the absence of bony abnormality fusion can be obtained with a DCP alone without the need for bone grafting


The Journal of Bone & Joint Surgery British Volume
Vol. 84-B, Issue 1 | Pages 19 - 22
1 Jan 2002
Kosygan KP Mohan R Newman RJ

We performed a randomised, prospective trial in 111 patients with intertrochanteric fractures of the hip comparing the use of the Gotfried percutaneous compression plate (PCCP) with that of the classic hip screw (CHS). Blood loss and transfusion requirement were less in the PCCP group but the operating time was significantly longer. The complication rate after operation was similar in both groups, and at a minimum follow-up of six months there was no difference in the rates of fracture healing or implant failure. The PCCP gives results which are similar to those obtained with a conventional device. Its suggested advantages seem to be theoretical rather than practical and, being a fixed-angle implant, it is not universally applicable


There is a growing trend towards using pre-clinical models of atrophic non-union. This study investigated different fixation devices, by comparing the mechanical stability at the fracture site of tibia bone fixed by either intramedullary nail, compression plate or external fixator. 40 tibias from adult male Wistar rats' cadavers were osteotomised at the mid-shaft and a gap of 1 mm was created and maintained at the fracture site to simulate criteria of atrophic non-union model. These were divided into five groups (n=8 in each): the first group was fixed with 20G intramedullary nail, the second group with 18G nail, the third group with 4-hole plate, the fourth group with 6-hole plate, and the fifth group with external fixator. Tibia was harvested by leg disarticulation from the knee and ankle joints, the soft tissues were carefully removed from the leg, and tibias were kept hydrated throughout the experiment. Each group was then subdivided into two subgroups for mechanical testing: one for axial loading (n=4) and one for 4-point bending (n=4). Statistical analysis was carried out by ANOVA with a fisher post-hoc comparison between groups. A p-value less than 0.05 was considered statistically significant. Axial load to failure data and stiffness data revealed that intramedullary nails are significantly stronger and stiffer than other devices, however there was no statistically significant difference axially between the nail thicknesses. In bending, load to failure revealed that 18G nails are significantly stronger than 20G. We concluded that 18G nail is superior to the other fixation devices, therefore it has been used for in-vivo experiments to create a novel model of atrophic non-union with stable fixation


Orthopaedic Proceedings
Vol. 85-B, Issue SUPP_I | Pages 38 - 38
1 Jan 2003
Kosygan K Newman R
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A randomised, prospective trial comparing the percutaneous compression plate (PCCP) and the classic hip screw was performed for intertrochanteric fractures of the femur in 108 patients. The PCCP offers the ability to stabilise fractures with a minimal exposure and periosteal stripping thus preserving soft tissue cover. Over a 19-month period all patients with extra-capsular fractures apart from subtrochanteric and pathologic fractures were included. They were classified as per Evans classification. The patient’s pre-operative haemoglobin, premorbid mobility, medical and mental status were noted. The duration of the procedure, screening time, blood loss and any technical difficulty encountered along with the post-operative haemoglobin, drainage and transfusion requirements, as well as the length of stay in the orthopaedic unit and total length of stay in the hospital were recorded. Results were analysed using the Chi-square test and Student’s test. The operating time was significantly longer in the PCCP group (mean 59vs49mins,P< 0.05). There was no significant difference between the two groups with regard to the other parameters measured. There was no difference in the failure rate (2 cut-outs in the CHS group and one screw back-out in the PCCP.) With the device being of fixed single angled design it proved to be unsuitable for 3 patients. The PCCP would appear to be as good as the more conventional device though it does not confer the perceived advantages of decreased duration of stay or significant reduction in transfusion requirement which are associated with other percutaneous procedures. The device is a single fixed angle one and is therefore not universally applicable to all patients


Orthopaedic Proceedings
Vol. 87-B, Issue SUPP_III | Pages 381 - 381
1 Sep 2005
Kish B Markuchevich M Engel I Hiram N Nyska M
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Purpose: To evaluate the use of locked Compression Plate (L.C.P.) in metaphyseal long bones fractures, and report our preliminary results. Materials and Methods: 23 patients 14–82 years old with long bones metaphyseal fractures underwent surgery with the use of L.C.P. between January 2004 and August 2004. Four patients were adolescents. 7 patients had Supracondylar femoral fracture. One of them had the fracture at the tip of IMN. 11 patients had distal Tibia, one had proximal+midshaft tibia and 4 had distal humerus fractures. All plates were prebended to fit the area of the fracture using a skeleton model. The plates were inserted percutaneously with reduction of the fracture. Partial weight bearing started after 6 weeks and full weight bearing started after 12 weeks. Results: Unuion was seen in x-ray after 6 to 12 week in 95% of patients. 20 patients regained full range of motion of the adjacent joints at 3 months follow-up. Complications: One patient developed compartment Syndrome in a high energy tibial fracture. One patient developed deep infection at the site of fibular plate not affecting the L.C.P. at the tibia. One patient developed temporary weakness of extensor Hallucis longus. Conclusions: L.C.P. proved to be effective in fixation of meta-epiphyseal zones which are difficult in IMN fixation. The use of this plate enables fixation of long bones in adolescents with open growth plate. The locking system enables good fixation of osteoporotic bones and in periprosthetic fracture. The high primary stability in combination with newly developed minimal-invasive techniques (MIPO = minimal invasive plate osteosynthesis) are the bases for a rapid bony consolidation, a low complication rate and good functional results


Orthopaedic Proceedings
Vol. 96-B, Issue SUPP_11 | Pages 130 - 130
1 Jul 2014
Schneider K Zderic I Gueorguiev B Richards R Nork S
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Summary. Biomechanically, a 2° screw deviation from the nominal axis in the PFLCP leads to significantly earlier implant failure. Screw deviation relies on a technical error on insertion, but in our opinion cannot be controlled intraoperatively with the existing instrumentation devices. Background. Several cases of clinical failure have been reported for the Proximal Femoral Locking Compression Plate (PFLCP). The current study was designed to investigate the failure mode and to explore biomechanically the underlying mechanism. Specifically, the study sought to determine if the observed failure was due to technical error on insertion or due to implant design. Methods. To exclude patient and fracture type related factors, an abstract foam block model simulating an unstable pertrochanteric fracture was created for three study groups with six specimens each (n=6). Group 1 was properly instrumented according to the manufacturer's guidelines. In Group 2 and 3, the first or second screw was placed in a posterior or anterior off-axis orientation by 2° measured in the transversal plane, respectively. Each construct was tested cyclically until failure using a test setup and protocol simulating complex axial and torsional loading. Radiographs were taken prior to and after the tests. Force, number of cycles and failure mode were compared. Results. The 2° screw deviation from the nominal axis led to significantly earlier construct failure in Group 2 and 3. The failure mode consisted of loosening of the off-axis screw due to disengagement with the plate, resulting in loss of construct stiffness and varus collapse of the fracture. Conclusions. In our biomechanical test setup, a screw deviation of only 2° from the nominal axis consistently led to the failure mode observed clinically. In our opinion, screw deviation mostly relies on technical error on insertion. But, proper screw insertion may be difficult or impossible with the existing instrumentation devices, especially as it cannot be controlled or guaranteed intraoperatively


Aim. The aim of this study was to compare the results of humerus intramedullary nail (IMN) and dynamic compression plate (DCP) for the management of diaphyseal fractures of humerus. Material & methods. 47 patients with diaphyseal fracture of shaft humerus were randomised prospectively and treated by open reduction and internal fixation with IMN or DCP. The criteria for inclusion were Grade 1.2a compound fractures; Polytrauma; Early failure of conservative treatment; Unstable fracture. Patients with pathological fracture, Grade 3 open fracture, refracture or old neglected fracture of humerus were excluded from the study. 23 patients underwent internal fixation by IMN and 24 by DCP. Reamed antegrade nailing was done in all cases. DCP was done through an anterolateral or posterior approach. Results. The outcome was assessed in terms of union time, union rate, functional outcome and incidence of complications. Functional outcome was assessed using the American Shoulder and Elbow Surgeons Score (ASES). On comparing the results by independent samples t test, there was no significant difference in ASES score between the two groups. The average union time was found to be significantly lower for IMN compared to DCP(P<.05). The union rate was found to be similar in both the groups. Complications like infection were found to be higher with DCP compared to IMN, while shortening of the arm (1.5-4cm) and restriction of shoulder movements due to impingement of the nail were found to be higher with DCP compared with IMN. However, this improved in all patients following removal of the nail once the fracture healed. Conclusion. This study proves that IMN can be considerd as a better surgical option for these fractures as it offers shorter union time and less incidence of serious complications like infection. However, there appears to be no difference between two groups in union rate and functional outcome