Osteoporotic Distal Femur Fractures Research Articles

Locked plate constructs are not necessarily stiffer than nonlocked constructs: A biomechanical investigation of locked versus nonlocked diaphyseal fixation in a human cadaveric model of nonosteoporotic and osteoporotic distal femoral fractures.

The objective of this study was to compare the biomechanical properties of locked and nonlocked diaphyseal fixation in a model of distal femur fractures using osteoporotic and nonosteoporotic human cadaveric bone. A supracondylar osteotomy was created to mimic a fracture (OTA/AO 33A3) in osteoporotic (n = 4) and nonosteoporotic (n = 5) cadaveric distal femurs. The left and right femurs of each pair were instrumented with a distal femoral locking plate and randomly assigned to have diaphyseal fixation with either locked or nonlocked screws. The construct was cyclically axially loaded, and construct stiffness and load to failure were evaluated. In osteoporotic bone, locked constructs were more stiff than nonlocked constructs (mean 143 vs. 98 N/mm when all time points combined, P < 0.001). However, in nonosteoporotic bone, locked constructs were less stiff than nonlocked constructs (mean 155 N/mm vs. 185 N/mm when all time points combined, P < 0.001). In osteoporotic bone, the average load to failure was greater in the locked group than in the nonlocked group (mean 1159 vs. 991 N, P = 0.01). In nonosteoporotic bone, the average load to failure was greater for the nonlocked group (mean 1348 N vs. 1214 N, P = 0.02). Bone mineral density was highly correlated with maximal load to failure (R2 = 0.92, P = 0.001) and stiffness (R2 = 0.78, P = 0.002) in nonlocked constructs but not in locked constructs. Contrary to popular belief, locked plating constructs are not necessarily stiffer than nonlocked constructs. In healthy nonosteoporotic bone, locked diaphyseal fixation does not provide a stiffer construct than nonlocked fixation. Bone quality has a profound influence on the stiffness of nonlocked (but not locked) constructs in distal femur fractures.

Comparison of radiological and functional results in osteoporotic distal femur fractures operated with single plating, lateral incision, and double plating, anterior paramedial incision: A retrospective study.

Treatment of osteoporotic distal femur fractures is often complicated by a high rate of nonunion and varus collapse. For such fractures, lateral plating with lateral incision and double plating with anterior paramedial incision have shown promising results in the recent literature. The hypothesis of this study was that bilateral plating of comminuted distal femur fractures in osteoporotic patients would result in higher union rates and lower revision rates compared to an isolated lateral locking plate. The study included 56 patients (23 males, 33 females) with supracondylar femur fracture. According to the OA/OTA classification, 9 were type A3, 8 were A2, 13 were C1, 16 were C2, and 10 were C3. The mean follow-up period was 12 months, with 29 patients treated using lateral mini-incision, lateral locking plate, and 27 patients treated with anterior paramedial incision, dual plating. The clinical and radiological results were evaluated. The mean duration of radiological union in the studied population was 15 ± 2.1 months (range, 11-21 months) in the single plate group (Group A), and 13.5 ± 2.6 months (range, 9-19 months) in the double plate group (Group B). Mean ROM was 112.3° and flexion contracture 4° in Group A, and ROM 108.3° and flexion contracture 6.7° in Group B. (P = .15). The average Western Ontario and McMaster Universities Arthritis Index (WOMAC) score was 85.6 points in Group A and 83.5 points in Group B (P = .2278). The postoperative anteversion measurement in the operated extremity ranged from -15 to 19 in Group A, and from 5 to 18 in Group B. When the anteversion degrees were compared between the injured and uninjured extremities in the postoperative period, a significant difference was observed within Group A (P = .0018), but no significant difference was observed in Group B (P = .2492). Dual plate fixation using the anterior paramedial approach is an effective operative method for osteoporotic distal femur fractures. This has many advantages such as precise exposure, easy manipulation, anatomic reduction, and stable fixation. However, for surgical indications and medial bone defects > 1 cm, grafting should be performed.

Tibiotalocalcaneal Arthrodesis with Hybrid Nail-Plate Constructs: A Novel Technique for Treatment of Unstable Ankle &amp; Hindfoot Deformities

Category: Ankle; Hindfoot Introduction/Purpose: Tibiotalocalcaneal (TTC) arthrodesis is a treatment option for several pathologies of the hindfoot and ankle. Traditional fixation options include intramedullary nailing or plate-screw constructs. In certain patients, for example when bone quality or post-operative compliance are of concern, more robust fixation may be desired. Charcot neuroarthropathy (CN) patients in particular often have complex deformities, poor bone quality, and impaired sensation. New trauma literature shows hybrid nail-plate constructs (NPCs) may permit early weight bearing in osteoporotic distal femur fractures. We report early results of TTC arthrodesis using NPCs in patients with complex deformities of the ankle and hindfoot. Methods: Patients undergoing TTC arthrodesis via intramedullary nail fixation plus plating by a single surgeon from September 2020 to December 2022 were included in our study. Indications included CN, post-traumatic deformities, and advanced arthritis. Age, comorbidities, Hemoglobin A1c, presence of an ulcer, implants, bone graft used, and postoperative complications were retrospectively recorded. Results: Fifteen patients met inclusion criteria. Six patients had CN; eight patients had post-traumatic complications; and one patient had an arthritic cavovarus deformity. Average age was 55 years (range 31-72). Eleven patients were treated with a lateral TTC locking plate; three were treated with an anterior tibiotalar arthrodesis plate; and one was treated with a 3.5mm reconstruction plate. All patients were treated with a TTC arthrodesis nail. In all cases, cellular bone matrix was used; in fourteen cases, autograft was also used. Average follow-up was 35 weeks (min. 12). Three patients underwent below-knee amputation, two for infection and the other for hardware failure. Two others required postoperative debridements but subsequently cleared their infections. Twelve patients have a stable, non-infected, ulcer free foot at latest follow-up. Conclusion: TTC arthrodesis can be used for a variety of indications, and many of these patients present complex challenges. Patients with CN in particular often have severe deformities and poor bone quality. Hybrid fixation methods provide added stability in complex cases, possibly allowing for more powerful deformity correction and earlier weight-bearing. We report a 80% favorable outcome rate in our case series, with major complications confined to patients with significant medical comorbidities (poorly controlled diabetes, peripheral vascular disease). We believe that TTC arthrodesis with hybrid nail-plate constructs represents an attractive solution to complex ankle and hindfoot deformities.

Stable internal fixation with dual plate technique for osteoporotic distal femur fractures

BackgroundOsteoporotic distal femur fractures are difficult in terms of fracture treatment and recovery. We hypothesized that the minimally invasive plate osteosynthesis (MIPO) with dual plate technique increased fixation stability and encouraged early mobilization and return to pre-fracture activity. Material and methodsBetween 2016 and 2019, 22 patients were treated with the dual plate technique for osteoporotic distal femur fractures. To evaluate the clinical outcome, the modified Western Ontario and McMaster Universities (WOMAC) score, Tegner activity score, knee range of motion (ROM), time to pain free full weight bearing from operation and patient satisfaction score were used. To evaluate the radiological outcome, the time to radiological union and varus or valgus angulation were measured. ResultsThe mean modified WOMAC score was 37.0 ± 6.5 (range, 26–42). There was no significant difference between preoperative and postoperative Tegner activity score (p = 0.436). Among 22 patients, 16 patients (72.7%) achieved preoperative activity level. The mean knee ROM was 106.1° ± 16.8° (range, 80–135). The time to pain free weight bearing was 7.4 ± 1.5 (range, 5–10) weeks. In patient satisfaction, 20 patients (90.9%) were very satisfied or somewhat satisfied. Bone union was achieved in all patients at 16.4 ± 4.3 (range, 13–22) weeks. The final follow-up valgus angle was 3.6° ± 4.0° (range, −2.5° - 10.9). ConclusionMIPO with the dual plate technique can provide rigid fixation for osteoporotic distal femur fractures. This stable and rigid fixation may allow early mobilization and return to pre-fracture activity.

Osteoporotic distal femur fractures in the elderly: peculiarities and treatment strategies.

Distal femur fractures account for 4-6% of osteoporosis related fractures of the femur in the elderly population. They represent a relevant cause of morbidity and mortality in the geriatric population with a reported 1-year mortality reaching 30%. Non-displaced fractures or even displaced fractures in patients with high operative risk can be treated conservatively. However, operative treatment is the most widely accepted management option for displaced fractures. The advantage resides in early mobilization and weight-bearing, reducing risks related with a prolonged immobilization when compared with conservative treatment. On the other hand, the intrinsic difficulty of fixing an osteoporotic bone is a major concern. The presence of osteosynthesis devices or prosthetic implants in the femur can make the surgical treatment more challenging, sometimes limiting therapeutic options. Aim of the present paper is to review the most recent literature about osteoporotic distal femur fractures in the elderly, including periprosthetic and other hardware related fractures, to highlight current evidence on management options and related results as a guide for the daily clinical practice. (www.actabiomedica.it)

Fixation of periprosthetic or osteoporotic distal femoral fractures with locking plates: a pilot randomised controlled trial

IntroductionWe hypothesised that the use of a polyaxial locking plate design offers the same clinical benefits as a monoaxial locking plate system following distal femoral osteoporotic/periprosthetic fracture fixation.MethodA multicentre prospective randomised pilot trial was conducted. Inclusion criteria were patients over 60 years with a displaced osteoporotic or periprosthetic distal femoral fracture. Details documented included time to union, complications, reinterventions and functional outcomes according to the Oxford knee score and EuroQol EQ-5D. Analysis of factors influencing an early fracture healing response was performed between those with clear features of radiological callus formation at three months. Statistical analysis was performed using a logistic regression model with multiple covariates assessed for each plate system (1:1 ratio) over a follow-up period of one year.ResultsForty patients (34 females) with a mean age of 77 (60–99) were recruited. Four patients deceased within the first six months. Twenty-five patients united by the six month follow-up. Six more patients progressed to union between six and nine months. Five patients developed non-union (two patients had implant failure; one in each group) and all underwent revision surgery. Malunion was evident in two cases, one with 15° of valgus (monoaxial plate), and one with 12° of recurvatum (polyaxial plate). Between the two plate systems, statistical analysis revealed no significant differences in most of the recorded parameters. Radiological features of early bone healing were present when the surgical approach was smaller (p = 0.015), and when a greater working length of the bridging plate was present (p = 0.016).ConclusionBoth plate systems demonstrated good union rates and limited implant related complications. Good reduction, mechanically sound construct and respect of the local fracture biology was more important than the particular plate design characteristics.

Single-Incision Double-Plating Approach in the Management of Isolated, Closed Osteoporotic Distal Femoral Fractures.

Introduction:Distal femoral fractures in elderly population had recorded an increase in incidence in the last 2 decades. Lateral distal femoral locking plating is considered one of the best options especially when dealing with comminuted fractures but varus collapse of the medial femoral condyle occurs frequently in patients with osteoporosis. Anatomical reduction of the fracture with stable rigid fixation using double-plating approach allows early mobilization of geriatric population and prevents varus collapse minimizing the comorbidities in such fractures.Patients and Methods:Between September 2014 and January 2017, a prospective study on 23 patients with comminuted osteoporotic distal femoral fractures managed through the double-plating approach through a single parapatellar approach has been conducted. Only osteoporotic geriatric patients with isolated distal femoral fractures were included. Polytraumatized, open fractures, and fracture type 33-A1, 33-A2, and 33-B were excluded. The mean age was 69.6 years (61-80). All patients have been evaluated as regard duration of procedure, time to union, EQ-5D-5L score, the need of autologous bone grafts, range of knee motion, and presence of complications.Results:The average follow-up was 14.1 months. The majority of fractures were type 33-C2 (13 patients). Average procedure time was 148 minutes (117-193 minutes). Mean EQ-5D-5 L score was 83.8 (72-82). Average time to union was 9 months (3-12 months). Four (17.4%) cases needed autologous bone graft after 6 months. No loss of reduction in any of the cases was evident, although 6 (26%) cases had screw breakage or cutout in one of the plate fixation. Two (8.7%) patient developed superficial wound infection and 1 (4.3%) developed DVT.Discussion:This study aimed at evaluation of the success of double plating of distal femoral fractures in geriatric population. different fixation methods were studied for reduction and fixation of such a fracture such as external fixation, intramedullary nails and lateral plating. the quality of fracture reduction, functional and radiological outcomes, time to union, the need for bone grafting and complication are the main debatable issues.Conclusion:Single-incision double-plating approach for distal femoral osteoporotic fractures is effective and provides stable construct without reduction loss allowing early rehabilitation. Delayed union and the need for bone graft are the major drawbacks for this technique.

Facteurs favorisant les fractures secondaires autour des plaques verrouillées pour fractures distales du fémur

IntroductionThe purpose of this study is to evaluate the outcomes and to analyze the risk factors for the occurrence of peri-implant fracture after treatment of osteoporotic distal femoral fractures using a locking plate. HypothesisRisk factors affecting peri-implant fracture exist after locking plate fixation in osteoporotic distal femur fracture. Materials and methodsEighty-nine cases (88 patients) with osteoporotic distal femoral fractures were evaluated between January 2006 and January 2014. The cohort included 13 men and 76 women with a mean age of 70.4 (50–91). Mean duration of follow-up was 47.9 months (12 to 106). All patients with distal femoral fracture were treated with a locking compression plate. Bone mineralized densitometry measurement was obtained from all patients. Risk factors including sex, age, rheumatoid arthritis (RA), taking of biphosphonates, primary or periprosthetic fracture after TKA (Total knee arthroplasty), open or closed fracture, types of the most proximal screw (locking/cortical), and number of proximal screws were analyzed. Complication, union, time to union, and range of motion of knee were also evaluated. ResultsAll patients had osteoporosis with the mean BMD of −3.16 (−2.5∼−5.4). The mean range of motion of knee was 126 degrees (90–145). Eighty four cases (94.4%) showed union, the mean time to union was 14 weeks (10–42). Peri-implant fractures occurred in four patients (4.5%) after bone union at mean 37.5 months (14–62) postoperatively. Eight patients had angular deformities of over 5 degrees. Non-union was observed in 5 cases and superficial wound infection in 2 cases. There were eight patients with RA, two of whom had suffered a peri-implant fracture. In statistical analysis, rheumatoid arthritis or periprosthetic fracture in TKA patients was a risk factor for peri-implant fracture (P=0.039, 0.019, respectively), and other factors showed no statistical differences. ConclusionsTreatment using a locking plate showed favorable outcomes in osteoporotic distal femoral fractures. However, peri-implant fracture could occur in patients with RA or periprosthetic fracture after TKA. Therefore, cautious consideration is required for management of osteoporotic distal femur fracture in patients with RA or periprosthetic fracture after TKA. Analysis of more cases will be needed in order to achieve conclusive results.

Factors affecting peri-implant fracture following locking plate for osteoporotic distal femur fractures

IntroductionThe purpose of this study is to evaluate the outcomes and to analyze the risk factors for the occurrence of peri-implant fracture after treatment of osteoporotic distal femoral fractures using a locking plate. HypothesisRisk factors affecting peri-implant fracture exist after locking plate fixation in osteoporotic distal femur fracture. Materials and methodsEighty-nine cases (88 patients) with osteoporotic distal femoral fractures were evaluated between January 2006 and January 2014. The cohort included 13 men and 76 women with a mean age of 70.4 (50–91). Mean duration of follow-up was 47.9 months (12 to 106). All patients with distal femoral fracture were treated with a locking compression plate. Bone mineralized densitometry measurement was obtained from all patients. Risk factors including sex, age, rheumatoid arthritis (RA), taking of bisphosphonate, primary or periprosthetic fracture after total knee arthroplasty (TKA), open or closed fracture, types of the most proximal screw (locking/cortical), and number of proximal screws were analyzed. Complication, union, time to union, and range of motion of knee were also evaluated. ResultsAll patients had osteoporosis with the mean BMD of −3.16 (−2.5∼−5.4). The mean range of motion of knee was 126 degrees (90–145). Eighty-four cases (94.4%) showed union, the mean time to union was 14 weeks (10–42). Peri-implant fractures occurred in four patients (4.5%) after bone union at mean 37.5 months (14–62) postoperatively. Eight patients had angular deformities of over 5 degrees. Nonunion was observed in 5 cases and superficial wound infection in 2 cases. There were eight patients with RA, two of whom had suffered a peri-implant fracture. In statistical analysis, rheumatoid arthritis or periprosthetic fracture in TKA patients was a risk factor for peri-implant fracture (P=0.039, 0.019, respectively), and other factors showed no statistical differences. ConclusionsTreatment using a locking plate showed favorable outcomes in osteoporotic distal femoral fractures. However, peri-implant fracture could occur in patients with RA or periprosthetic fracture after TKA. Therefore, cautious consideration is required for management of osteoporotic distal femur fracture in patients with RA or periprosthetic fracture after TKA. Analysis of more cases will be needed in order to achieve conclusive results. Level of evidenceTherapeutic study, level IV (retrospective study). See the Guidelines for Authors for a complete description of levels of evidence.

From Bench to Bedside: How Stiff is Too Stiff? Far-cortical Locking or Dynamic Locked Plating May Obviate the Question.

From Bench to Bedside: How Stiff is Too Stiff? Far-cortical Locking or Dynamic Locked Plating May Obviate the Question.

Evaluation of the results of internal fixation of comminuted osteoporotic distal femur fractures with locked plates

Background Internal fixation using locked plates is a well-established method for the treatment for osteoporotic distal femoral fractures. Aim This study aimed to evaluate the clinical, functional, and radiological outcomes after using locked plates for internal fixation of osteoporotic distal femoral fractures. Patients and method This prospective study was carried out on 12 patients, four men and eight women, who attended Suez Canal University Hospitals between June 2011 and January 2013; the mean age of the patients was 65 years (range, 55-80 years) at the time of surgery. The patients included in the study had unstable comminuted osteoporotic distal fractures of the femur and were treated with locked compression plates. Clinical and functional evaluation was carried out after 1 year of follow-up on the basis of the International Knee Society (IKS) functional recovery score according to Insall and colleagues. Radiological evaluation was also performed 1 year postoperatively according to Ehlinger and colleagues . Results The mean range of motion was 110°, and the mean IKS score was 145. The bone union rate was 92% within a mean of 12 weeks. The infection rate was 8%, which improved with frequent dressing, without the need for revision. Patients were assessed for satisfactory results 1 year postoperatively according to Smith and colleagues: 10 patients (84%) achieved satisfactory results, and two patients (16%) did not achieve satisfactory results because of delayed union and knee stiffness. Conclusion The locked plate is an effective method for fixation of comminuted and osteoporotic distal femoral fractures in elderly patients, with good clinical and radiological outcomes.

Implant augmentation: adding bone cement to improve the treatment of osteoporotic distal femur fractures: a biomechanical study using human cadaver bones.

The increasing problems in the field of osteoporotic fracture fixation results in specialized implants as well as new operation methods, for example, implant augmentation with bone cement. The aim of this study was to determine the biomechanical impact of augmentation in the treatment of osteoporotic distal femur fractures.Seven pairs of osteoporotic fresh frozen distal femora were randomly assigned to either an augmented or nonaugmented group. In both groups, an Orthopaedic Trauma Association 33 A3 fractures was fixed using the locking compression plate distal femur and cannulated and perforated screws. In the augmented group, additionally, 1 mL of polymethylmethacrylate cement was injected through the screw. Prior to mechanical testing, bone mineral density (BMD) and local bone strength were determined. Mechanical testing was performed by cyclic axial loading (100 N to 750 N + 0.05N/cycle) using a servo-hydraulic testing machine.As a result, the BMD as well as the axial stiffness did not significantly differ between the groups. The number of cycles to failure was significantly higher in the augmented group with the BMD as a significant covariate.In conclusion, cement augmentation can significantly improve implant anchorage in plating of osteoporotic distal femur fractures.

Feasibility study on the potential of a spiral blade in osteoporotic distal femur fracture fixation

Osteoporotic fractures of the distal femur (primary as well as periprosthetic) are a growing problem in today's trauma and orthopaedic surgery. Therefore, this feasibility study should identify the biomechanical potential of a (commercially available) spiral blade in the distal femur as compared to a single screw without any additional plate fixation. Additionally, the influence of cement augmentation was investigated. An artificial low density bone model was either instrumented with a perforated spiral blade or a 5 mm locking screw only. Additionally, the influence of 1 ml cement augmentation was investigated. All specimens were tested with static pull-out and cyclic loading (50 to 250 N with an increment of 0.1 N/cycle). In the non-augmented groups, the mean pull-out force was significantly higher for the blade fixation (p < 0.001). In the augmented groups, the difference was statistically not significant (p = 0.217). Augmentation could increase pull-out force significantly by 72 % for the blade and 156 % for the screw, respectively (p = 0.001). The mean number of cycles to failure in the non-augmented groups was 12,433 (SD 465) for the blade and 2,949 (SD 215) for the screw, respectively (p < 0.001). In the augmented group, the blade reached 13,967 (SD 1,407) cycles until failure and the screw reached 4,413 (SD 1,598), respectively (p < 0.001). The investigated spiral blade was mechanically superior, significantly, as compared to a screw in the distal femur. These results back up the further development of a distal femoral blade with spiral blade fixation for the treatment of osteoporotic distal femur fractures.

The potential of implant augmentation in the treatment of osteoporotic distal femur fractures: A biomechanical study

PurposeOsteoporotic fractures of the distal femur are an underestimated and increasing problem in trauma and orthopaedic surgery. Therefore, this study investigates the biomechanical potential of implant augmentation in the treatment of these fractures. MethodsTwelve osteoporotic surrogate distal femora were randomly assigned to the augmented or non-augmented group. All specimens were fixed using the LCP DF. In the augmented group additionally 1ml Vertecem V+ was injected in each screw hole before screw positioning. The construct represents an AO 33 A3 fracture. Biomechanical testing was performed as sinusoidal axial loading between 50 and 500N with 2Hz for 45,000 cycles, followed by loading between 50 and 750N until failure. ResultsThe augmented group showed significant higher axial stiffness (36%). Additionally the displacement after 45,000 cycles was 3.4 times lower for the augmented group (0.68±0.2mm vs. 2.28±0.2mm). Failure occurred after 45,130 cycles (SD 99) in all of the non-augmented specimens and in two specimens of the augmented group after 69,675 cycles (SD 1729). Four of the augmented specimens showed no failure. The failure mode of all specimens in both groups was a medial cut-out. ConclusionsThis study shows a promising potential of implant augmentation in the treatment of osteoporotic distal femur fractures.

Biomechanical Characterization of an Osteoporotic Artificial Bone Model for the Distal Femur

The treatment of osteoporotic distal femur fractures is still an unsolved problem of trauma surgery. The poor bone stock often leads to secondary loss of reduction and implant failure. Therefore, the development of new implants and their biomechanical testing is essential. In a previous study, we developed and initially characterized an artificial osteoporotic bone model of the distal femur. This follow-up study was performed to characterize this model in a biomechanical comparison. We investigated two different artificial bones: five foam cortical shell (Sawbones) and 10 custom-made artificial femoral condyles. Additionally, eight human femora were used for comparison. For biomechanical testing, two intramedullary nails (distal femur nail (DFN) and supracondylar nail (SCN)) were cyclically axial loaded in an AO 33 C2 unstable distal femoral fracture model. In our testing, the artificial bone showed a decrease in the axial stiffness of 27% for the SCN and 28% for the DFN compared to the human results. Also the number of cycles for a deformation of 2.5 mm was reduced by 55% (SCN) and 62% (DFN). This decrease was homogenous and caused by the relative high bone mineral density of the human specimen used. The modes of failure showed no difference between the artificial and human bones. Our customized artificial bone provides suitable results. In relation to the human bones classified as mildly osteoporotic, we assume that the biomechanical properties match to serve as an osteoporotic bone. Yet, we suggest to check transferability of the results with human material.

The Effect of Locked Distal Screws in Retrograde Nailing of Osteoporotic Distal Femur Fractures

To examine the effects of locked distal screws in retrograde nails used in unstable osteopenic distal femur fractures. Biomechanical testing of paired human cadaveric femurs. Seven matched pairs of embalmed, moderately osteopenic cadaver femurs were instrumented with 12-mm intramedullary nails in a statically locked, retrograde fashion. One femur of each pair had locked distal screws and the other femur had unlocked distal screws. A 2.5-cm gap of bone was cut nine centimeters from the distal condyles to simulate an unstable fracture. The locked distal screw nails were compared to unlocked distal screw nails for collapse of the fracture gap, medial-lateral and anterior-posterior translation of the nail within the fracture site, and fracture angulation. The femurs were axially loaded, cycled, and then loaded to failure. Motion at the fracture site with axial cyclic loading and site of failure when loaded to failure. After cycling, both locked distal screw and unlocked distal screw nails demonstrated several millimeters medial and anterior translation within the fracture site and approximately 1 mm collapse of the fracture gap. Although no statistically significant differences were found, the locked distal screw nails had less anterior and medial translation, angulation, and collapse of the fracture gap after cycling. Loads to failure were similar for both locked distal screw and unlocked distal screw nails. It was noted that proximal femur failure occurred at the level of the proximal screw hole in the nail at the subtrochanteric level in 7 (4 locked distal screws and 3 unlocked distal screw groups) of the 14 samples. Four other samples failed through the intertrochanteric region (2 locked distal screw and 2 unlocked distal screw groups) and the remainder within the distal fragment by fracture of the femur along the medial cortex. Although most differences in fixation stability were not significant, the locked distal screw nails exhibited less fracture collapse and anterior and medial translation of the nail at the fracture site than the unlocked distal screw nails. The degree of varus angulation after cyclic loading was also less for the locked distal screw nails. The length of the nail chosen should avoid having proximal locking screws distal to the lesser trochanter, thus averting proximal femur stress risers and fractures.

Treatment of distal femoral fractures in the elderly using a less-invasive plating technique.

We treated 16 patients having fractures of the distal femur with the less-invasive stabilization system (LISS). Patients' mean age was 75 (62-101) years. Fifteen patients had low-energy trauma. Eight fractures were type A (AO classification), three were type B and five were type C. In two cases, loosening of the proximal fixation was seen and surgical revision performed. Union time averaged 30 (16-68) weeks. There was no non-union. Average Oxford knee score was 46 (22-60). No loosening of the distal fixation was found. LISS appears to be an effective device in treating osteoporotic distal femoral fractures.

The AO dynamic condylar screw for fractures of the femur

We report our initial experience in Nottingham of use of the AO Dynamic Condylar Screw (DCS) implant system for internal fixation of fractures of the proximal and distal femur. The implant has been used in 24 cases over a 2-year period, and with an average follow-up of 1 year the results have been as favourable as those in reports of other comparable implants, but there have been a number of technical difficulties, particularly with the fixation of osteoporotic distal femoral fractures. The DCS can be used in all situations where the 95 ° blade plate has previously been used and technically it is easier to insert correctly. We conclude that whilst the DCS may replace the corresponding blade plates in the orthopaedic surgeon's armamentarium, it does not solve the problems of fixation of osteoporotic fractures. The indications for and difficulties of such internal fixations are discussed.