Knee-spanning External Fixator Research Articles

THE MANCHESTER PATTERN KNEE-SPANNING EXTERNAL FIXATOR: A MECHANICAL COMPARISON WITH TRADITIONAL EXTERNAL FIXATOR CONSTRUCTS

IntroductionKnee dislocations, vascular injuries and floating knee injuries can be initially managed by a external fixator. Fixator design constructs include the AO pattern and the Diamond pattern. However, these traditional constructs do not adhere to basic principles of external fixation. The Manchester pattern knee-spanning external fixator is a new construct pattern, which uses beam loading and multiplanar fixation. There is no data on any construct pattern. This study compares the stability of these designs.Materials & MethodsHoffman III (Stryker, USA) external fixation constructs were applied to articulated models of the lower limb, spanning the knee with a diamond pattern and a Manchester pattern. The stiffness was loaded both statically and cyclically with a Bose 3510 Electroforce mechanical testing jig (TA Instruments). A ramp to load test was performed initially and cyclical loading for measurement of stiffness over the test period. The results were analysed with a paired t-test and ANOVA.ResultsThe mean stiffness with the diamond pattern fixator was significantly less stiff than the Manchester pattern fixator – by a factor of 3 (40N/mm vs 115N/mm). Displacement increased in all patterns over simulated loading equating to six weeks. The diamond pattern demonstrated a 50%% increase in displacement over time. The Manchester pattern demonstrated only 20% increase in displacement over time. These are all statistically significant (p<0.01)ConclusionsThe aim of an external fixator in knee dislocations and vascular injuries is to provide stability, prevent displacement and protect repairs. Vascular injuries often require fixation for several weeks to protect a repair. The Manchester pattern, applying the principles of external fixation, provides a stiffer construct and also confers greater stability over the time a fixator may be required. We commend this more informed design for the management of knee dislocations and vascular injuries.

Magnetic resonance imaging quality in the context of a knee-spanning external fixator placed inside the MR bore: a literature review.

After emergent assessment of potentially limb-threatening injuries in knee dislocation or multi-ligament knee injury patients, magnetic resonance imaging is necessary to visualize ligamentous structures and plan for soft tissue repair. However, the application of a knee-spanning external fixator may introduce artifact and reduce overall image quality, which can limit the evaluation of soft tissue injury. As a result, the utility of MRI in the context of a knee-spanning external fixator has been called into question. Signal-to-noise ratio, contrast-to-noise ratio, and qualitative scales have been used to assess image quality of MRI in the context of a knee-spanning external fixator. Despite the potential for artifact, studies have demonstrated that useful diagnostic information may be obtained from MRI in the presence of an external fixator. This review examines the general principles of anatomical assessment, magnetic field strength, device composition and design, radiofrequency coil use, and MRI sequences and artifact reduction as they pertain to MRI in the presence of a knee-spanning external fixator.

Perspectives and institutional policies on patient safety and image quality regarding the use of knee-spanning external fixators in MRI: A survey study of the Society of Skeletal Radiology.

Concerns regarding patient safety and image quality have made the use of knee-spanning external fixators in MRI a challenging clinical scenario. The purpose of our study was to poll practicing musculoskeletal radiologists on their personal experiences regarding the use of knee-spanning external fixators in MRI in an effort to consolidate practice trends for the radiologists' benefit. A 27-item survey was created to address the institutional use, safety, adverse events, quality, and perspectives of the radiologist related to MRI of an externally fixated knee. The survey was distributed to 1739 members of the Society of Skeletal Radiology. A total of 72 members of the Society of Skeletal Radiology completed the survey. Most notably, 40 of 72 (55.56%) respondents are permitted to place a knee-spanning external fixator inside the MR bore at their institution, while19 of 72 (26.39%) respondents are not permitted to do so. Fourteen of 32 (43.75%) respondents have institutional guidelines for safely performing an MRI of an externally fixated knee. Twenty-five of 32 (78.13%) respondents are comfortable permitting an MRI of an externally fixated knee. We found a general lack of consensus regarding the decision to scan a patient with a knee-spanning external fixator in MRI. Many institutions lack safety guidelines, and providers rely upon a heterogeneous breadth of resources for safety information. A re-examination of the FDA device labeling nomenclature and expectations of the individual manufacturers may be needed to bridge this gap and help direct management decisions placed upon the provider.

Patient Safety in MRI with the Use of a Joint-Spanning External Fixator for Knee Dislocation: A Critical Analysis Review.

» Universal safety guidelines for the use of a knee-spanning external fixator in magnetic resonance imaging (MRI) are unlikely to be established considering the high variability in device construct configurations.» Per the US Food and Drug Administration, manufacturers are to provide parameters for safe MRI scanning for "MR Conditional" devices; however, such labeling may be limited in detail. Physicians should reference manufacturer labels as a starting point while making an educated clinical decision.» Scanning of a knee-spanning external fixator inside the MR bore has been safely demonstrated in previous studies, although with small sample sizes.» When considering MRI in a patient treated with a knee-spanning external fixator, physicians should use all available resources and coordinate with their medical team to make a clinically reasonable decision contrasting patient benefit vs. potential harm.

Lateral femoral distraction is a safe and necessary adjunct for articulator visualization during the operative treatment of tibial plateau fractures

IntroductionRecent evidence suggests use of lateral femoral distractor (LFD) to aid in visualization during surgery for tibial plateau fractures (TPF) may result in an unacceptably high rate of iatrogenic peroneal nerve palsy. We sought to evaluate femoral distractor use for open reduction internal fixation (ORIF) of TPF and quantify the incidence of peroneal nerve palsy. MethodsWe retrospectively evaluated all patients undergoing ORIF of TPF between 2014 and 2019 by a single fellowship trained orthopaedic traumatologist at a single Level 1 trauma center. Inclusion criteria were use of a LFD during ORIF of TPF. Exclusion criteria were preoperative neurovascular injury in the operative extremity and distraction via pre-existing external fixator. Parameters included patient demographic variables, intraoperative techniques, postoperative outcomes, and fracture classification. Documented clinical exam was used to evaluate peroneal nerve status and injuries were classified as complete or incomplete. Incomplete injuries were classified as sensory or motor. ResultsOf 303 patients undergoing ORIF for a TPF, femoral distraction was used in 254 (83.8%) cases, with 201 utilizing applied intraoperative femoral distraction and 53 utilizing pre-existing knee-spanning external fixation for distraction. Three patients were excluded for preoperative sensory peroneal nerve palsy with 175 patients meeting inclusion criteria. The most common fracture type was lateral split depression (n = 130). Zero patients developed complete or incomplete peroneal nerve palsy. DiscussionOur study found no incidence of peroneal nerve palsy when using lateral femoral distraction. This study supports the utilization of lateral distraction for articular visualization and reduction during ORIF of TPF.

Cost Reduction for Knee-Spanning External Fixation in the Staged Treatment of Tibial Plateau Fractures: A Practical Intervention.

To determine whether an educational intervention affects surgeon implant decision making measured by total implant costs for temporizing a knee-spanning external fixation construct. A total of 24 cases were prospectively collected after an educational intervention and matched to 24 cases before intervention using Schatzker classification and by surgeon. A single Level 1 trauma center. Forty-eight patients with Schatzker II-VI tibial plateau fractures. Education session to create transparency with component pricing and to provide 3 clinical cases of Orthopaedic Trauma Association/AO 41-C3 (Schatzker VI) with accompanying images and fixator construct costs. Total implant costs displayed in the session ranged from $2354 to $11,696. External fixator construct cost. The mean cost of constructs in the postintervention group was $4550.20 [95% confidence interval (CI) $3945.60-$5154.00], which was significantly different compared with the preintervention group cost of $6046.75 (95% CI = $5309.54-$6783.97, P = 0.003). After 1 year, the total implant costs of external fixation constructs were reduced by an average of almost $1500 per patient. An educational intervention created a reduction in the average total implant construction costs for temporary knee-spanning external fixation in the treatment of tibial plateau fractures. Surgical implant selection and cost variance remain an ideal area to improve value for patients and hospitals. Empowering surgeons with knowledge regarding implant prices is a critical part of working toward the cost reductions of external fixation constructs.

Outcomes after ORIF of Bicondylar Schatzker VI (AO type C) Tibial Plateau Fractures in an Elderly Population

BackgroundThe surgical management of bicondylar tibial plateau (BTP) fractures in elderly patients aims to restore knee stability while minimizing soft tissue complications. The purpose of this study was to compare injury characteristics and surgical outcomes after ORIF of BTP fractures (AO/OTA 41-C (Schatzker VI)) in young (< 50 years) versus elderly (> 65 years) patients. MethodsA retrospective cohort study was conducted using data from two American College of Surgeons (ACS) level I trauma centers. Inclusion criteria were: (1) age 18 years or older, (2) bicondylar tibial plateau fracture (AO/OTA 41-C or Schatzker VI), (3) treatment with ORIF, and (4) minimum of 6 months follow-up. Patients between 50 and 65 years of age were excluded. Data collection was performed by reviewing electronic medical records, operative reports, and radiology reports. ResultsWe identified 323 patients (61% male) with 327 BTP fractures and a median follow-up of 685 days. There were 230 young patients (71%) < 50 years and 93 elderly patients (29%) >6 5 years at time of presentation. Elderly patients were significantly more likely to have a low energy mechanism of injury (44.6 vs. 16.2%, p < 0.001), and present with diabetes (19.4 vs. 4.4%, p < 0.001) or coronary artery disease (12.9 vs. 1.3%, p < 0.001). Elderly patients were also significantly less likely to undergo staged management with initial knee-spanning external fixation followed by delayed ORIF (19.2 vs. 33.9%, p = 0.008). Elderly patients had a lower arc of motion at final follow-up (105 vs. 113°, p < 0.001) and reduced PROMIS-10 function scores (43.8 vs. 49.8, p = 0.013). No differences were observed in rates of superficial infection, deep infection, reoperation, or EQ-5D scores between age groups. ConclusionsThis is the largest study to compare injury characteristics and outcomes after ORIF of BTP fractures according to age. Elderly patients (age > 65 years) sustained BTP fractures by lower energy mechanisms than their younger counterparts with similar fracture patterns and were often managed with ORIF. The results of this study suggest that ORIF of BTP fractures in elderly patients is associated with similar complication rates and outcomes as in younger patients despite higher comorbidities and poorer bone quality in the elderly population.

Is pin-plate overlap in tibial plateau fractures associated with increased infection rates?

IntroductionDespite advances in the treatment of high energy proximal tibia fractures, including the utilization of staged management with external fixation, the infection rate remains high. Overlap between external fixator pin sites and definitive internal fixation has been proposed as a risk factor for infection. MethodsThis retrospective study reviews 244 patients with staged knee-spanning external fixation followed by delayed definitive internal fixation at two separate level one trauma centers. Presence of pin-plate overlap as well as several other known risk factors for infection were recorded and measured to include open fractures, compartment syndrome, operative time and number of incisions. Development of deep infection was the primary outcome. Both univariate and multivariate statistics were applied to determine differences in rates of infection. Results65 (26.6%) patients had presence of pin-plate overlap while 179 (73.4%) patients had no overlap. There were no differences between overlapping and non-overlapping groups with respect to other infectious risk factors. Deep infection occurred in 34 (13.9%) total patients, 18 (27.7%) were in patients with pin-plate overlap and 16 (8.9%) in those without overlap. (P = 0.003; RR 3.01, 95% CI 1.51–4.76). DiscussionThis large, multicenter study demonstrated a statistically significant association between pin-plate overlap and the development of deep infection in tibial plateau fractures. On multivariate analysis, pin-plate overlap was identified as an independent risk factor for infection. When treating these complex injuries, surgeons should consider the definitive fixation construct when placing external fixation pins.

Pure Obturator Dislocation of the Hip, a Rare Variety of Regular Dislocations, and Long-Term Clinical Outcomes

Introduction: Traumatic knee dislocation is considered an orthopedic emergency. Knee dislocations are relatively infrequent injuries. This injury frequently occurs from high-energy impact trauma. Neurovascular injuries can result in debilitating consequences if the diagnosis and treatment are delayed. Associated complications include degenerative arthritis, permanent neurovascular injury, and amputation. The poorest prognosis is seen in patients with knee dislocation longer than 6-8 hours before reduction. History: The 25-year-old male patient presented with a history of a road traffic accident to the emergency department. The patient presented with swelling, pain, and deformity of the left knee and leg. Examination: On examination, the patient had tense swelling and tenderness of the left knee joint and leg. Visible deformity of the left knee joint is seen. The posterior tibial artery and dorsalispedis artery were not palpable. Active ankle and toe movements were absent. Investigations: Plain radiograph was taken at the emergency department of the left knee and leg. X-rays showed anterior dislocation of the knee joint. Treatment: After valid written informed consent, the dislocated left knee joint was reduced under sedation in the operation theatre and immobilized in the above knee plaster slab. Reduction of the knee joint was done within 4 hours of injury. Then the distal pulses were re-assessed. The posterior tibial and dorsalispedis artery was absent. Hence, MR Angiography of the left lower limb was done. It showed popliteal artery transection. So, the artery was explored and end-to-end vascular anastomosis was done. A knee-spanning external fixator was applied to the left lower limb. Fasciotomy was done for the tense leg compartments. After a week, the fasciotomy wounds were infected for which extensive debridement of the wounds was done and antibiotic beads were placed. Knee was mobilized with a gradual range of motion exercises and non-weight bearing mobilization with a foot drop splint. Gradually full weight-bearing ambulation was allowed. Conclusion: Knee dislocation is rare, albeit a serious and potentially limb-threatening condition. The prognosis of knee dislocations is variable and is heavily dependent on the time interval between trauma and initiation of management. Immediate, timely, and proper management can salvage the limb, and amputation is not the only solution. Keywords: Dislocation, Posterior tibial artery, Fasciotomy

Acute Femoral Nailing and Ipsilateral Knee-Spanning External Fixation: Improved Early Stability for Floating Knee Injuries Involving the Tibial Plateau.

Ipsilateral femoral shaft and tibial plateau fractures, termed a "floating knee," are rare and challenging injuries. There is limited literature guiding the operative technique and the outcomes associated with these injuries. The author's preferred technique is early intramedullary of the femoral shaft fracture with knee-spanning external fixation of any length unstable plateau fractures in the same operative setting. Early fixation of the femur fracture allows for improved hemodynamic and inflammatory stability. External fixation of the tibial plateau restores length and alignment and allows for soft tissue rest until definitive fixation. The purpose of this study is to describe this operative technique and determine the infection rate and complications requiring return to the operating room in patients with femoral shaft fractures and length unstable plateau fractures.

External Fixation Devices Within the Magnetic Resonance Imaging Bore: A Safety and Radiologic Analysis.

To (1) report the thermal changes encountered at the pin/skin interface in a cadaver with a knee-spanning external fixator inside the magnetic resonance imaging (MRI) bore and (2) report on the quality of the MRI sequences collected. Three commonly used external fixation systems were placed on cadaveric lower extremities to simulate knee external fixation. Fiber optic thermal probes were placed at the pin/skin interface of a femoral and tibial pin. A control probe was embedded in the soft tissues of the thigh. Full knee MRI scans were performed using a 1.5-Tesla magnet. Real-time thermal data were collected. A clinically significant increase in temperature compared with the control was defined as 2°C. Two blinded radiologists evaluated the images for image quality and overall diagnostic utility using a standardized 5-point grading scale. There were statistically significant differences in the temperature changes between the femoral/tibial pin sites and the control probe sites during each phase of the MRI scan. However, there was only one clinically significant difference in temperature change during a single sequence of one MRI scan of one of the external fixator devices. Overall image quality was graded as a 4 for each image set with 100% interobserver agreement (k = 1.0). Despite significant differences in temperature changes between the pin sites and controls over multiple MRI sequences in commonly used external fixator devices, the differences in temperature change are likely not clinically relevant. Overall image quality and interpretability of the images were excellent.

Knee Stiffness After Tibial Plateau Fractures: Predictors and Outcomes (OTA-41).

What patient characteristics and injury factors predict decreased knee range of motion (ROM) after operative management of tibial plateau fractures? Prospective cohort study. Academic medical center. Over 11 years, tibial plateau fractures at a single academic institution were prospectively followed. A total of 266 patients were included in this study. Surgical repair of tibial plateau fractures and secondary interventions due to arthrofibrosis. Clinical outcomes were evaluated using the Short Musculoskeletal Function Assessment and ROM at 3-month, 6-month, and long-term follow-up. Secondary outcomes were considered as the need for a subsequent procedure due to arthrofibrosis. At 3-month follow-up, the mean ROM was 113 degrees. By long-term follow-up (mean = 17 months), the mean ROM improved to 125 degrees. Independent predictors of decreased knee ROM were the following: at 3-month follow-up, open fractures (P = 0.047), application of a knee-spanning external fixator (P = 0.026), orthopaedic polytrauma (P = 0.003), and tibial spine involvement (P = 0.043); and at long-term follow-up, nonwhite ethnicity (P = 0.003), increasing age (P = 0.003), and a deep infection (P = 0.002). Ten patients (3.7%) required a secondary procedure for arthrofibrosis. There was a significant improvement in the knee ROM (P < 0.001) and functional outcomes (P = 0.004) following the intervention. At long-term follow-up, independent predictors of decreased knee ROM were nonwhite ethnicity, increasing age, and sustaining a postoperative complication of a deep infection. Secondary interventions were reliable treatments for arthrofibrosis. Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Surgical Technique: Achieving Reduction With Temporizing, Knee-Spanning External Fixation

Peri- and intra-articular fractures about the knee are frequently managed with joint-spanning external fixation before definitive treatment. With a systematic approach, a near-anatomic reduction with respect to length, alignment, and rotation can be obtained. This video highlights 2 clinical cases: a bicondylar tibial plateau fracture-dislocation and a distal femur fracture, both of which were treated with temporizing, knee-spanning external fixation. The indications, principles, and biomechanics of knee-spanning external fixation are presented. In addition, we demonstrate a systematic approach to applying knee-spanning external fixation. Temporizing, joint-spanning external fixation is a critical treatment modality in the orthopaedic armamentarium for managing fractures about the knee. With a systematic approach, it is possible to obtain a near-anatomic reduction with respect to length, alignment, and rotation.

Surgical management of posterior knee dislocation associated with extensor apparatus rupture

ObjectiveThe purpose of this study was to report the clinical and functional results of patients who underwent surgical management for posterior knee dislocation associated with extensor apparatus rupture. IntroductionPosterior knee dislocations associated with extensor apparatus ruptures are defined as rare but complicated injuries, which are difficult to return to the level of activity prior to the injury. The study demonstrated a hypothesis that good knee stability and early gain of range of motion could be achieved with deliberate design of the treatment protocol and proper application of the instruments. MethodsFifteen patients with posterior knee dislocations associated with extensor apparatus ruptures were evaluated after reduction and repair of extensor apparatus. Following that, multiple-ligament reconstruction in association with use of a lateral knee-spanning external fixator was applied for at least six weeks. Ligament reconstructions were performed using allografts. Range of motion and knee stability were both measured at each follow-up evaluation at a mean time of 36months. The assessment was made using the Lysholm Knee Scoring Scale. ResultsThe mean Lysholm scale score was 87.6 (range 73–95), with excellent in 11 cases, good in two, and fair in two. In the final evaluation, the range of motion was a mean range of 123.4° (range 100–135). ConclusionThe use of a lateral knee-spanning external fixator ensured the safety of repaired vessels, knee stability after reduction, and early rehabilitation with range of motion.

Ultrasound-assisted external fixation: a technique for austere environments

IntroductionUltrasound-assisted external fixation of long bones has the potential to enhance extremity damage control surgery in locations without fluoroscopy, such as forward surgical elements, the intensive care unit, and spacecraft....

Bar diameter is an important component of knee-spanning external fixator stiffness and cost.

The authors' objective was to determine the effects of bar diameter on the stiffness and cost of a knee-spanning external fixator. The authors studied 2 versions of an external fixator with a difference in bar diameter (small bars, 8-mm diameter; large bars, 11-mm diameter). Fixators were tested using frame dimensions and a synthetic fracture model appropriate for a tibial plateau fracture. Five configurations of each fixator were tested: standard, cross-link, oblique pin, double stack, and super construct. The construct stiffness of each configuration (n=60) was measured in anterior-posterior bending, medial-lateral bending, axial torsion, and axial compression. Cost analysis allowed for calculation of the stiffness per unit cost. In the large bar group, an increase in construct stiffness was noted for all constructs and testing modes. Magnitude of stiffness increase ranged from 24% to 224% (P<.05 in all cases), depending on the configuration and loading mode. Increase in stiffness was so large that double-stack small bars performed similarly to standard construct large bars. Considering that the frame components have similar costs, the double-stack small bar fixator results in a 66% increase in cost for the same stiffness provided by the standard large bar. Bar diameter seems to have a large effect on knee-spanning external fixators. The authors observed an increase in stiffness of up to 191% under anterior-posterior bending despite an increase in bar size of only 37.5%. This finding might allow clinicians to use less expensive frames constructed of larger bars without sacrificing construct stiffness.

Analysis of strategies to increase external fixator stiffness: Is double stacking worth the cost?

We compared the mechanical benefits and costs of 3 strategies that are commonly used to increase knee-spanning external fixator stiffness (resistance to deformation): double stacking, cross-linking, and use of an oblique pin. At our academic trauma centre and biomechanical testing laboratory, we used ultra-high-molecular-weight polyethylene bone models and commercially available external fixator components to simulate knee-spanning external fixation. The models were tested in anterior–posterior bending, medial–lateral bending, axial compression, and torsion. We recorded the construct stiffness for each strategy in all loading modes and assessed a secondary outcome of cost per 10% increase in stiffness. Double stacking significantly increased construct stiffness under anterior–posterior bending (109%), medial–lateral bending (22%), axial compression (150%), and torsion (41%) (p<0.05). Use of an oblique pin significantly increased stiffness under torsion (25%) (p<0.006). Cross-linking significantly increased stiffness only under torsion (29%) (p<0.002). Double stacking increased costs by 84%, cross-linking by 28%, and use of an oblique pin by 15% relative to a standard fixator. All 3 strategies increased stiffness under torsion to varying degrees, but only double stacking increased stiffness in all 4 testing modalities (p<0.05). Double stacking is most effective in increasing resistance to bending, particularly under anterior–posterior bending and axial compression, but requires a relatively high cost increase. Clinicians can use these data to help guide the most cost-effective strategy to increase construct stiffness based on the plane in which stiffness is needed.

Infection After Spanning External Fixation for High-Energy Tibial Plateau Fractures: Is Pin Site–Plate Overlap a Problem?

The purpose of this study was to determine whether overlap between temporary external fixator pins and definitive plate fixation correlates with infection in high-energy tibial plateau fractures. Retrospective chart and radiographic review. Academic medical center. Seventy-nine patients with unilateral high-energy tibial plateau fractures formed the basis of this report. Placement of knee-spanning external fixation followed by delayed internal fixation for high-energy tibial plateau fractures treated at our institution between 2000 and 2008. Demographic patient information was reviewed. Radiographs were reviewed to assess for the presence of overlap between the temporary external fixator pins and the definitive plate fixation. Fisher exact and t test analyses were performed to compare those patients who had overlap and those who did not and were used to determine whether this was a factor in the development of a postoperative infection. Development of infection in those whose external fixation pin sites overlapped with the definitive internal fixation device compared with those whose pin sites did not overlap with definitive plate and screws. Six knees in six patients developed deep infections requiring serial irrigation and débridement and intravenous antibiotics. Of these six infections, three were in patients with closed fractures and three in patients with open fractures. Two of these six infections followed definitive plate fixation that overlapped the external fixator pin sites with an average of 4.2 cm of overlap. In the four patients who developed an infection and had no overlap, the average distance between the tip of the plate to the first external fixator pin was 6.3 cm. There was no correlation seen between infection and distance from pin to plate, pin-plate overlap distance, time in the external fixator, open fracture, classification of fracture, sex of the patient, age of the patient, or healing status of the fracture. Fears of definitive fracture fixation site contamination from external fixator pins do not appear to be clinically grounded. When needed, we recommend the use of a temporary external fixation construct with pin placement that provides for the best reduction and stability of the fracture, regardless of plans for future surgery.

Operative strategy in postero-medial fracture-dislocation of the proximal tibia

Objective In 1981, Moore introduced a new classification for dislocation-type fractures caused by high-energy mechanisms. The most common medial Moore-type fractures are entire condyle fractures with the avulsion of the median eminence (tibial anterior cruciate ligament (ACL) insertion). They are usually associated with a posterolateral depression of the tibial plateau and an injury of the lateral menisco-tibial capsule. This uniform injury of the knee is increasingly observed in the recent years after skiing injuries due to the high-speed carving technique. This uprising technique uses shorter skis with more sidecut allowing much higher curve speeds and increases the forces on the knee joint. The aim of this study was to describe the injury pattern, our developed operative approach for reconstruction and outcome. Methods A total of 28 patients with 29 postero-medial fracture dislocation of the proximal tibia from 2001 until 2009 were analysed. Clinical and radiological follow-up was performed after 4 years on average (1 year in minimum). Evaluation criteria included the Lysholm score for everyday knee function and the Tegner score evaluating the activity level. All fractures were stabilised post primarily. The surgical main approach was medial. First, the exposure of the entire medial condyle fracture was performed following the fracture line to the articular border. The posterolateral impaction was addressed directly through the main fracture gap from anteromedial to posterolateral. Small plateau fragments were removed, larger fragments reduced and preliminarily fixed with separate K-wire(s). The postero-medial part of the condyle was then prepared for main reduction and application of a buttress T-plate in a postero-medial position, preserving the pes anserinus and medial collateral ligament. In addition, a parapatellar medial mini-arthrotomy through the same main medial approach was performed. Through this mini-arthrotomy, the avulsed anterior eminence with attached distal ACL is retained by a transosseous suture back to the tibia. Results We could evaluate 26 patients (93%); two patients were lost to follow-up due to foreign residence. Median age was 51 years (20–77 years). The fractures were treated post primarily at an average of 4 days; in 18 cases a two-staged procedure with initial knee-spanning external fixator was used. All fractures healed without secondary displacement or infection. As many as 25 patients showed none to moderate osteoarthritis after a median of 4 years. One patient showed a severe osteoarthritis after 8 years. All patients judge the clinical result as good to excellent. The Lysholm score reached 95 (75–100) of maximal 100 points and the Tegner activity score 5 (3–7) of maximal 10 points (competitive sports). The patients achieved a median flexion of 135° (100–145°). Conclusion In our view, it is crucial to recognise the different components of the injury in the typical postero-medial fracture dislocation of the proximal tibia. The described larger medial approach for this type of medial fracture dislocation allows repairing most of the injured aspects of the tibial head, namely the medial condyle with postero-medial buttressing, the distal insertion of the ACL and the posterolateral impaction of the plateau.

The Effect of Knee-Spanning External Fixation on Compartment Pressures in the Leg

External fixation is frequently used for provisional and/or definitive stabilization of open and closed fractures and dislocations involving the lower extremity. There is some concern, however, that application of an external fixator with subsequent reduction of the fractures with distraction may precipitate the development of compartment syndrome. The hypothesis of this study was that application of external fixation and restoration of limb length would have no effect on the compartment pressures. Prospective cohort study. Academic medical center, 2 level 1 trauma centers. Between October 2003 and May 2006, 25 patients who met inclusion criteria and underwent immediate knee-spanning external fixation. All 4 compartments of the injured leg were measured with a Solid-State Transducer Intra Compartment device or an arterial line set-up during the temporizing procedure at 4 different time points. In addition, at the time each pressure reading was taken, the patient's diastolic pressure was recorded from the anesthesia monitor. Elevation of compartment pressure at any of 4 distinct time points during the procedure. Each of the compartments was measured and recorded 4 times: (1) after the patient had been draped but before any fixation or reduction of the fracture, (2) immediately after the insertion of the fixator pins, (3) immediately after reduction of the fracture, and (4) 5 minutes after the reduction. A threshold of less than 30 mm Hg differential from diastolic pressure in conjunction with clinical examination was set as an indication for 4-compartment fasciotomy. : Twenty-five patients with a mean age of 52 years (range, 21-69 years) were enrolled in the study. Injuries included proximal tibial fractures (Orthopaedic Trauma Association types, 41) in 21 patients; knee fracture-dislocation (Moore type II) in 2 patients, and knee (femoro-tibial) dislocations in 2 patients. Two fractures were open, and all other injuries were closed. Fasciotomy was required in 3 cases at initial compartment measurement. In the remaining 22, there were no significant trends toward increased compartment pressures as a result of external fixation placement and knee reduction. There were 9 patients (41%) who had a transient DeltaP < 30 mm Hg at some point during surgery. No patient had a DeltaP < 30 mm Hg sustained through the conclusion of the procedure, and no compartments were released in any of these patients. None of the patients in the study developed compartment syndrome after surgery, and no sequelae of compartment syndrome were noted at minimum 6-month follow-up. Application of knee-spanning external fixation as a temporary measure for stabilization of high-energy proximal tibial fractures and dislocations may result in transient elevation of intracompartmental pressure of the leg. Although DeltaP may fall below the threshold of 30 mm Hg, this does not appear to lead to compartment syndrome.