Comparison of magnetic resonance imaging with operative findings in acute traumatic dislocations of the adult knee

Diagnosis and treatment strategies of the multiligament injured knee: a scoping review

OBJECTIVE

To map the current literature evaluating the diagnosis and treatment of multiligament knee injuries (MLKIs).

DESIGN

Scoping review.

DATA SOURCES

Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for scoping reviews and Arksey and O'Malley frameworks were followed. A three-step search strategy identified relevant published literature comprising studies reporting on at least one aspect in the diagnosis or treatment of MLKI in adults. Data were synthesised to form a descriptive analysis and thematic summary.

RESULTS

Overall, 417 studies were included. There was a substantial chronological increase in the number of studies published per year, with 70% published in the last 12 years. Of included studies, 128 (31%) were narrative reviews, editorials or technical notes with no original data. The majority of studies (n=239, 57%) originated from the USA; only 4 studies (1%) were of level I evidence. Consistent themes of contention included clinical assessment, imaging, operative strategy, timing of surgery and rehabilitation. There was a lack of gender and ethnic diversity reported within patient groups.

CONCLUSIONS

There remains insufficient high-level evidence to support definitive management strategies for MLKI. There is considerable heterogeneity in outcome reporting in current MLKI literature, precluding robust comparison, interpretation and pooling of data. Further research priorities include the development of expert consensus relating to the investigation, surgical management and rehabilitation of MLKI. There is a need for minimum reporting standards for clinical studies evaluating MLKI.

Accuracy of Magnetic Resonance Imaging in the Diagnosis of Multiple Ligament Knee Injuries: A Multicenter Study of 178 Patients

BACKGROUND

Magnetic resonance imaging (MRI) has shown limited diagnostic accuracy for multiple ligament knee injuries (MLKIs), especially posterolateral corner (PLC) injuries.

HYPOTHESIS

The diagnostic accuracy of MRI for MLKIs will only be moderate for some knee structures. Patient-related factors and injury patterns could modify the diagnostic accuracy of MRI.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

All patients with MLKIs surgically treated between January 2014 and December 2020 in the centers participating in the study were reviewed. We recorded sex, age, mechanism of injury, time from injury to MRI, and vascular and neurological associated lesions. Lesions to the anterior cruciate ligament (ACL), posterior cruciate ligament, medial collateral ligament, lateral collateral ligament (LCL), popliteus tendon, popliteofibular ligament, iliotibial band, biceps tendon, medial and lateral meniscus, and articular cartilage from MRI reports and surgical records were also collected. The sensitivity, specificity, positive predictive value, negative predictive value, diagnostic accuracy, diagnostic odds ratio, positive and negative likelihood ratio, and intraclass correlation coefficient of MRI were calculated for each knee structure. With logistic regression, associations between patient and injury characteristics and MRI accuracy were assessed.

RESULTS

A total of 178 patients (127 male; mean age, 33.1 years) were included. High-energy trauma was the most common mechanism of injury (50.6%), followed by sports trauma (38.8%) and low-energy trauma (8.4%). The ACL was the structure with the best diagnostic accuracy, diagnostic odds ratio, and positive predictive value (94.4%, 113.2, and 96.8%, respectively). PLC structures displayed the worst diagnostic accuracy among knee ligaments (popliteus tendon: 76.2%; LCL: 80.3%) and diagnostic odds ratio (popliteus tendon: 9.9; LCL: 17.0; popliteofibular ligament: 17.5). MRI was more reliable in detecting the absence of meniscal and chondral lesions than in identifying them. Logistic regression found that the diagnostic accuracy was affected by the Schenck classification, with higher Schenck grades having worse diagnostic accuracy for peripheral structures (iliotibial band, popliteus tendon, and biceps tendon) and improved diagnostic accuracy for the ACL and posterior cruciate ligament.

CONCLUSION

The diagnostic accuracy of MRI for MLKIs largely varied among knee structures, with many of them at risk of a misdiagnosis, especially PLC, meniscal, and chondral lesions. The severity of MLKIs lowered the diagnostic accuracy of MRI for peripheral structures.

The accuracy of MRI in diagnosing and classifying acute traumatic multiple ligament knee injuries

Background

Magnetic resonance imaging (MRI) is widely used for the evaluation of knee injuries, however, the accuracy of MRI in classifying multiple ligament knee injuries (MLKIs) remains unknown. This study aimed to investigate the accuracy of MRI in diagnosing and classifying acute traumatic MLKIs, we hypothesize that MRI had high accuracy in detecting and classifying MLKIs.

Methods

The clinical data of 97 patients who were diagnosed with acute traumatic MLKIs and managed by multi-ligament reconstruction between 2012 and 2020 were retrospectively reviewed. The MR images were read by two experienced radiologists and results were compared with intraoperative findings, which were considered as the reference for the identification of injured structures. The value of MRI in detecting injuries of anterior cruciate ligament (ACL), posterior cruciate ligament (PCL), medial collateral ligament (MCL), lateral collateral ligament (LCL), and meniscus was evaluated by calculating the sensitivity, specificity, positive predictive value, negative predictive value, positive likelihood ratio, negative likelihood ratio, and kappa coefficients analysis. The value of MRI in classifying MLKIs was evaluated by calculating the agreement between MRI and intraoperative findings.

Results

For detecting the specific injured structures in MLKIs, MRI had high sensitivity (90.7% for ACL, 90.4% for PCL, and moderate specificity (63.6% for ACL, 50% for PCL) in detecting cruciate ligament injuries, moderate sensitivity (79.1% for MCL, 55.6% for LCL) and specificity (46.7% for MCL, 68.4% for LCL) in detecting collateral ligament injuries, fair sensitivity (61.5%) and low specificity (39.4%) in the diagnosis of injuries to the meniscus. For classifying the MIKIs, MRI had a moderate agreement with intraoperative findings in classifying KD-V (kappa value = 0.57), poor agreement in the KD-I (kappa value = 0.39) and KD-IIIM (kappa value = 0.31), meaningless in the KD-II and KD-IIIL (kappa value < 0). The overall agreement between MRI and intraoperative findings in classifying MLKIs was poor (kappa value = 0.23).

Conclusions

MRI is valuable in early detection and diagnosis of acute MLKIs, however, the accuracy of MRI in classifying MLKIs is limited. The management of MLKIs should be based on intraoperative findings, physical examinations, and comprehensive imaging results.

MRI of Traumatic Knee Dislocation: A Study to Evaluate Safety and Image Quality for Patients with Knee-Spanning Stabilization Devices

This study evaluated safety and image quality of MRI exams performed for patients with traumatic knee dislocations in knee-spanning stabilization devices. It is an IRB-approved retrospective design with waived informed consent that included 63 patients with traumatic knee dislocation. 56 patients had metallic external fixators, and 7 patients had non-metallic knee immobilizers. 7 patients had bilateral dislocations yielding a total of 70 knee MRIs. 1.5 Tesla MRI exams were performed for all patients who were awake and alert at the time of imaging. All knee-spanning external fixators were considered "MR conditional" by the FDA. The electronic medical record was reviewed for notes from the technologist and nursing staff documenting any patient complaints or adverse events during the MRI exam as required by departmental protocol. Qualitative analysis of the six most frequently performed sequences were independently conducted by 2 musculoskeletal radiologists using a 5-point Likert scale. Overall image quality and select time intervals between the two groups were compared using an independent sample t test and the Mann-Whitney U test, respectively. No adverse events were reported for a 40-minute average estimated patient scan time with the stabilization devices in the MR gantry. Mean values of Likert scale scores were generated from two readers' data for comparison between the external fixation and the immobilizer groups. Most knee MRI exams with external fixators were within diagnostic quality despite artifacts (grade 3). MRI exams generally were of higher diagnostic quality in the immobilizer group than the external fixator group (p < 0.05). The external fixator models included DePuy Synthes, Smith and Nephew, Stryker Hoffman III, Zimmer FastFrame, and Zimmer XtraFix. MRI examinations in patients with external fixators for traumatic knee dislocations can be safely performed under certain conditions and provide diagnostic quality images.

Posterior cruciate ligament lesions are mainly present as combined lesions even in sports injuries

PURPOSE

To analyse 1000 consecutive patients, treated with isolated or combined posterior cruciate ligament (PCL) reconstruction in a single centre according to the epidemiological factors and differences in injury patterns depending on the activity during trauma.

METHODS

Between 2004 and 2019, one thousand isolated and combined PCL reconstructions were performed. The medical charts and surgical reports of all patients were analysed regarding epidemiological factors. The PCL lesions were divided into isolated and combined lesions with at least one additional ligamentous injury. The influence of activity during accident and additional injury on the presence of isolated or combined lesions and injury patterns was calculated.

RESULTS

In 388 patients (38.8%), sporting activity was the main activity in PCL lesions, followed by traffic accidents in 350 patients (35.0%). Combined injuries were present in 227 patients (58.5%) with sports injuries and 251 patients (71.7%) with traffic accidents. Only during handball, an isolated PCL lesion (69.1%) was more common than a combined lesion. Highest rate of combined lesions was present in car accidents (91.7%). In all activities except skiing and biking, the most common additional peripheral injury was a tear of the posterolateral corner. In skiing and biking accidents, the most common additional peripheral lesion was a lesion of the medial collateral ligament. In patients with PCL lesion and additional fracture of the same lower extremity, a combined lesion was more common than an isolated lesion (p = 0.001).

CONCLUSION

Combined PCL lesions are more common than isolated lesions, even in sports injuries (except handball). Incidence and injury pattern vary depending on activity during trauma. Main additional peripheral lesion is a lesion of the posterolateral corner, except biking and skiing accidents where a medial lesion is more common.

LEVEL OF EVIDENCE

Level III.

Meniscal root tears occur frequently in multi-ligament knee injury and can be predicted by associated MRI injury patterns

PURPOSE

The frequency of meniscal root tears in association with multi-ligament knee injury has not been established but adds to the complexity of surgical reconstruction and may have long-term consequences. Therefore, identifying root tears, on preoperative imaging, is important. The aim of this study was to identify the frequency of meniscal root tears, on preoperative magnetic resonance imaging, following multi-ligament injury and distinguish associated injury patterns that may aid detection.

METHODS

Cases were identified from a prospectively collected institutional database. The magnetic resonance imaging of 188 multi-ligament injuries [median age 31 years (range 16-64)] was retrospectively reviewed by three musculoskeletal radiologists with the presence of meniscal injuries recorded alongside the ligament injury pattern and intra-articular fractures. Assessment of injury pattern was solely made on this imaging.

RESULTS

38 meniscal root injuries were identified in 37 knees (overall frequency = 20.2%; medial = 10.6%; lateral = 9.6%). The frequency of meniscal root tears was not increased in higher grade injuries (21.5% vs. 17.0%, n.s.). Valgus injury patterns were associated with lateral root tears (p < 0.05) and varus patterns were associated with medial root tears (p < 0.05). Further, fractures in the same compartment were associated with both medial and lateral root tears (p < 0.05).

CONCLUSIONS

Meniscal root tears occur more frequently in multi-ligament knee injury than previously reported with isolated anterior cruciate rupture. Root tears can be predicted by ligament injury patterns and fractures sustained (suggestive of a compressive force). In multi-ligament cases, the preoperative magnetic resonance imaging can be used to detect these tears and associated patterns of injury.

LEVEL OF EVIDENCE

IV.

How sensitive and specific is 1.5 Tesla MRI for diagnosing injuries in patients with knee dislocation?

PURPOSE

The purpose of this study was to assess the sensitivity and specificity of 1.5 T magnetic resonance imaging (MRI) in diagnosing and identifying the specific injury pattern in patients with knee dislocation. The hypothesis was that the sensitivity and specificity are low in patients with posterolateral corner injury and/or PCL tear.

METHODS

A retrospective study was performed on 38 patients (m:f = 29:9, mean age ± SD 34.3 ± 14.0) with traumatic knee dislocation, who underwent 1.5 T MRI prior to surgery. MRI scans were analysed by a musculoskeletal radiologist, and the presence and type of tears to ligaments, tendons and meniscus or bone were recorded. Comparison was made with the intraoperative findings from the surgical records using the same reporting scheme. The agreement between MRI and surgical findings was assessed using kappa statistics, and the sensitivity and specificity were calculated.

RESULTS

In patients with knee dislocation, MRI was found to have low sensitivity (25-38 %) but high specificity (94-97 %) for diagnosing injury to the posterolateral corner. There was high sensitivity in the diagnosis of tears in the cruciate and collateral ligaments (97-100 %); the specificity, however, was lower (50-67 %). The diagnosis of meniscal injury showed low sensitivity (36-56 %) and moderate specificity (69-83 %).

CONCLUSIONS

MRI is a sensitive measure of cruciate and collateral ligament injury in acute knee dislocation; however, it does not reliably diagnose injury to the posterolateral corner or meniscus, and therefore, a higher index of suspicion is required during arthroscopy to prevent misdiagnosis which could affect long-term clinical outcome.

LEVEL OF EVIDENCE

Diagnostic study, Level II.

Dynamic intraligamentary stabilization and primary repair: a new concept for the treatment of knee dislocation

BACKGROUND

Traumatic knee dislocation represents a rare but devastating injury. Several controversies persist regarding type of treatment, surgical timing, graft selection, repair versus reconstruction of the medial and lateral structures, surgical techniques and postoperative rehabilitation. A new technique for primary ACL stabilization, dynamic intaligamentary stabilization (DIS) was developed at the authors' institution. The purpose of this study was to analyze the clinical and radiological outcomes of surgically treated traumatic knee dislocations by means of the DIS technique for the ACL, primary suturing for PCL, MCL and LCL.

METHODS

Between 2009 and 2012, 35 patients treated surgically for traumatic knee dislocation with primary anterior cruciate ligament (ACL) reconstruction with DIS, suturing of the posterior cruciate ligament (PCL) and primary complete repair of collaterals, were evaluated clinically (IKDC score, SF12 health survey, Lysholm score, Tegner score) and radiologically with a mean follow up of 2.2 years (range 1.00-3.50 years) years. Instrumented anterior-posterior translation was measured (KT-2000).

RESULTS

Anterior/posterior translation (KT-2000) for the healthy and injured limb was 4.8mm (range 3-8mm) and 7.3mm (range 5-10) (89N) respectively. Valgus and varus stress testing in 30° flexion was normal in 26 (75%) and 29 (83%) patients, respectively. The IKDC score was B in 29 (83%) and C in 6 (17%) patients, while the mean Tegner score was 6 (range 4-8). The mean Lysholm score was 90.83 (range 81-95) and mean SF-12 physical and mental scores were 54.1 (range 45-60) and 51.0 (range 39-62) respectively. In 2 patients, a secondary operation was performed.

CONCLUSIONS

Early, one stage reconstruction with DIS can achieve good functional results and patient satisfaction with overall restoration of sports and working capacity without graft requirements.

Staged management of knee dislocation in polytrauma injured patients

INTRODUCTION

Knee dislocation in the polytrauma setting is rare. The optimal method that this injury should be managed remains controversial. We therefore undertook a study to evaluate the incidence and outcomes of knee dislocation in polytrauma patients treated in our institution.

PATIENTS AND METHODS

From January 2005 to February 2011, two hundred-seventy five polytrauma patients were managed in our institution. Knee dislocation was present in 14 patients (4%): 4 females, mean age 46 years (range 19-52), mean ISS 24 (range 18-34) and 10 males, mean age 45 years (18-48), mean ISS 28 (range 18-48). Knee dislocation was classified according to the Schenck classification. MRI was used routinely for accurate assessment of the knee lesions. Treatment protocol consisted of initially management with the ATLS guidelines, neurovascular assessment, emergency surgical care simultaneously with reanimation procedures and hospitalization at ICU. Upon full evaluation and stabilization of the patient's physiological status and acquisition of a knee MRI scan, one- to three-stage operative treatment was performed. Decision for one- or more-stage treatment was based on the evaluation of the systemic and local clinical status, injury classification, timing of surgery, and consequences that remained after associated injuries. Clinical outcome was evaluated by IKDC 2000 Subjective knee evaluation, IKDC Clinical Examination Scales and the Tegner-Lysholm scale. A specific accelerated rehabilitation program was completed according to the surgical treatment. The mean follow up was 2 years (range 19-48 months).

RESULTS

Patients had a different type of knee dislocations: five KD II, six KD III, two KD V2 and one KD V3. Clinical results were low in patients that underwent the three-staged protocol, and good and high in one- or two-staged operative treatment respectively at the two year follow up. The difference between the results in three groups of treated patients was visible but not statistically significant.

CONCLUSION

The physiological state of the patient along with the type of knee lesion dictates a timing and type of stage treatment. The best postoperative clinical results are fulfilled with the one-stage treatment and it should be the first choice of knee dislocation therapy. Two-stage treatment should be performed only if the general clinical status of polytrauma injured patient or local knee status does not allow a complete knee reconstructive surgery. Three-stage treatment results with the worst outcome and it should be avoided.

Knee Dislocation: Descriptive Study of Injuries

Objective

Describe the ligamentous and associated injuries that occur in the traumatic knee dislocation, relating them to the mechanisms of trauma and to identify patterns of injuries.

Methods

Twenty three knee dislocations were described in the period between March 2010 and March 2011. After the diagnosis of the lesions, the reduction and transarticular external fixation of the dislocated knees were done. At the second moment, the patients were evaluated with physical examination under anesthesia and the surgical exploration of peripheral lesions was perfomed by a surgeon of the knee surgery group of this institution. The patients data with the description of the injuries were found and registered.

Results

65% of patients were male, the average age was 35 years and the most common mechanism of trauma was the motorcycle accident (60%). The lesion of the anterior cruciate ligament (ACL) occurred in 75% of the cases, and the lesion of posterior cruciate ligament (PCL) in 95%. The medial peripheral injuries happened in 65% of the dislocations, and the lateral lesions in 40%. The most common dislocations were classified as KDI (25%) and as KDIIIm (25%). The arterial injury was present in 15% of the cases, and the nervous injury where registered in one patient (5%). At the initial radiographic evaluation, 45% of the dislocations presented reduced.

Conclusion

The characteristics of the knee dislocations described showed a great range of variability demonstrating that an individualized evaluation of each case is mandatory. The surgeon should be able to recognize and choose the correct treatment to these lesions.

Surgical approach to the posteromedial corner: indications, technique, outcomes

Injuries to the medial side of the knee can occur in isolation or in conjunction with multiple other ligaments about the knee. In addition, medial knee injuries can involve isolated injury to the medial collateral ligament or include the posteromedial structures of the knee. Treatment strategies differ greatly depending on injury pattern. In order to select an appropriate treatment strategy, one must accurately diagnose the injury pattern based on clinical examination and the use of appropriate imaging studies. The fundamental basis for diagnosis of a medial sided knee injury stems from understanding the static and dynamic stabilizing structures that compose the medial side of the knee. It is our aim to define the anatomic roles of medial sided structures, their importance in protecting the biomechanical stability of the knee, as well as provide indications and our preferred procedures for surgical management of these complex injuries.

Relevancy and reproducibility of magnetic resonance imaging (MRI) interpretation in multiple-ligament injuries and dislocations of the knee

INTRODUCTION

After multiple-ligament injuries and dislocations of the knee, clinical assessment of the soft tissues is difficult and MRI is generally performed.

HYPOTHESIS

MRI is a reliable examination, providing a precise and reproducible assessment of soft-tissue lesions after multiple-ligament injuries or dislocations of the knee.

MATERIALS AND METHODS

Forty patients presenting multiple-ligament lesions of the knee were included in this multicenter prospective study. All had an MRI of the knee in the 48 h following their accident. Thirty-four patients were treated surgically. A 17-item standardized interpretation guide was created. Intraobserver reproducibility was assessed by comparing the interpretations of five surgeons at two different times 3 weeks apart. Interobserver reproducibility was evaluated by comparing the results of the interpretations of 40 MRIs performed by three pairs of surgeons. The relevance of the MRI interpretations was determined by comparing the results of the surgeons to those of a radiologist and with the data from the surgical reports.

RESULTS

The overall intraobserver and interobserver agreement was low. Comparing the surgeon's results with the radiologist's results and the surgical data, the agreement was low.

DISCUSSION

After multiple-ligament injuries and dislocations of the knee, a precise diagnosis is necessary. This study provides an isolated demonstration of the lack of precision and reproducibility of MRI interpretations for the diagnosis of the lesion's topography. MRI should be integrated into a complete assessment with a precise clinical exam and stress X-rays.

LEVEL OF EVIDENCE

Level IV, prospective case-control study.

ACR appropriateness criteria(®) acute trauma to the knee

There are more than 1 million visits to the ER annually in the United States for acute knee trauma. Many of these are twisting injuries in young patients who can walk and bear weight, and emergent radiography is not required. Several clinical decision rules have been devised that can considerably reduce the number of radiographic studies ordered without missing a clinically significant fracture. Although fractures are seen on only 5% of emergency department knee radiographs, 86% of knee fractures result from blunt trauma. In patients with falls or twisting injuries who have focal tenderness, effusion, or inability to bear weight, radiography should be the first imaging study performed. If radiography shows no fracture, MRI is best for evaluating for a suspected meniscal or ligament tear or patellar dislocation. Patients with knee dislocation should undergo radiography and MRI, as well as fluoroscopic angiography, CT angiography, or MR angiography. The ACR Appropriateness Criteria(®) are evidence-based guidelines for specific clinical conditions that are reviewed every 2 years by a multidisciplinary expert panel. The guideline development and review include an extensive analysis of current medical literature from peer-reviewed journals and the application of a well-established consensus methodology (modified Delphi) to rate the appropriateness of imaging and treatment procedures by the panel. In those instances in which evidence is lacking or not definitive, expert opinion may be used to recommend imaging or treatment.

Stiffness of knee-spanning external fixation systems for traumatic knee dislocations: a biomechanical study

OBJECTIVE

The purpose of this study was to compare the relative stiffness of four common external fixation (XF) configurations used to span and stabilize the knee after knee dislocation.

METHODS

Synthetic composite femora and tibiae connected with cords were used to simulate a knee. Four configurations of external fixation were tested: anterior femoral pins with monotube (XF1), anterolateral femoral pins with monotube (XF2), anterolateral femoral pins with two connecting rods (XF3), and hinged ring fixator (XF4). Six specimens of each configuration were loaded nondestructively in varus/valgus, anterior-to-posterior shear, flexion/extension, axial compression, internal/external torsion, and failure in varus.

RESULTS

XF2 was stiffer than XF1 in varus, valgus, and axial loading (P < 0.01) demonstrating that anterolateral pins provided greater stiffness than anterior femoral pins. XF3 was stiffer than XF2 in varus, valgus, and anterior-to-posterior shear (P < 0.002), indicating that two connecting rods provided greater stiffness than the monotube. XF4 was similar to the other configurations in anterior-to-posterior shear and torsion, indicating the hinged frame provided adequate stability. The average load to failure in varus mode was 250 N-m, which was far beyond the nondestructive loading of all specimens. There was no statistical difference between the different constructs in load to failure.

CONCLUSIONS

The stiffest construct for external fixation of a knee dislocation was achieved when pins were placed anterior lateral on the femur and two connecting rods were used. A stiffer construct may provide a better clinical outcome and we therefore recommend this frame configuration.

Clinical and radiological outcomes after management of traumatic knee dislocation by open single stage complete reconstruction/repair

Background

The purpose of our study was to analyze the clinical and radiological long-term outcomes of surgically treated traumatic knee dislocations and determine prognostic factors for outcome.

Methods

Retrospective consecutive series of patients treated surgically for traumatic knee dislocation with reconstruction/refixation of the anterior (ACL) and posterior cruciate ligaments (PCL) and primary complete repair of collaterals and posteromedial and posteromedial corner structures. 68 patients were evaluated clinically (IKDC score, SF36 health survey, Lysholm score, Knee Society score, Tegner score, visual analogue scale - VAS pain and satisfaction, Cooper test) and radiologically (weight bearing and stress radiographs) with a mean follow up of 12 ± 8 years. Instrumented anterior-posterior translation was measured (Rolimeter, KT-1000). Pearson correlation and stepwise regression analysis was used.

Results

82% of patients (n = 56) returned to their previous work. At final follow-up 6 patients (9%) suffered from pain VAS > 3. The mean side-to-side difference of anterior/posterior translation (KT-1000, 134N) was 1.6 ± 1.6 mm and 2.6 ± 1.4 mm. Valgus and varus stress testing in 30° flexion was <3 mm (normal) in 57 patients (86%). The IKDC score was normal/nearly normal in 38 (58%) patients and the mean Lysholm score 83 ± 17 (intact 98 ± 7). The median Tegner score decreased from 7 preinjury (range 3-10) to 5 at follow-up (range 0-10). The mean Knee Society score was 187 ± 15 (out of maximum 200). In 7 patients (10%) a secondary ligament reconstruction was performed. Three patients (4%) underwent a high tibial osteotomy and four (6%) received a primary unconstrained total knee replacement. According to the Kellgren Lawrence osteoarthritis score only mild degenerative changes were present. The stress radiographs showed stable results for anteroposterior translation. Injury of the lateral collateral ligament, refixation of the ACL/PCL and delayed surgery >40 days were significantly associated with worse outcome (p < 0.05).

Conclusions

Early complete reconstruction can achieve good functional results and patient satisfaction with overall restoration of sports and working capacity. Negative predictive factors for outcome were injury pattern, type of surgical procedure and timing of surgery.

The role of preoperative MRI in knee arthroscopy: a retrospective analysis of 2,000 patients

The aim of this study was to investigate, to what extent routine preoperative MRI scans could set the indications for knee arthroscopies and reduce the number of diagnostic arthroscopies. For this retrospective cohort study, 1,000 patients who had knee arthroscopies documented in 1994/1995 were compared with 1,000 patients that were treated in 2004/2005. The preoperative diagnoses that gave indications for knee arthroscopy were compared with the intraoperative findings. The congruence of preoperative diagnosis with the intraoperative findings was evaluated comparing both study populations. The number of patients who were referred to orthopaedic trauma surgeons with MRI increased from 24% to 56%. A high congruence of preoperative diagnosis and intraoperative findings was found in 49% in 1994/1995 and 55% in 2004/2005. However, regarding the most important outcome parameter, the number of diagnostic arthroscopies, no improvement was found (3% in both periods). The presented data suggests that MRI scans are not routinely necessary as an indication for knee arthroscopy, as clinical examination and plain radiograph are sufficient. However, MRI scans do allow a more detailed characterization of the expected findings and can therefore be helpful in therapy planning.

[Traumatic knee dislocation with popliteal vascular disruption: retrospective study of 14 cases]

PURPOSE OF THE STUDY

Complex femorotibial dislocation of the knee joint generally results from high-energy trauma caused by a traffic or a contact sport accident. Besides disruption of the cruciate ligaments, in 10-25% of patients present concomitant palsy of the common peroneal nerve and more rarely disruption of the popliteal artery. The purpose of this work was to assess outcome in a monocentric consecutive series of knee dislocations with ischemia due to disruption of the popliteal artery and to focus on specific aspects of management.

MATERIAL AND METHODS

This retrospective series included eleven men and three women, aged 18 to 74 years (mean 47 years). The right knee was injured in five and the left knee in six. Trauma resulted from a farm accident in six patients, fall from a high level in two, a traffic accident in three and a skiing accident (fall) in one. Two other patients with morbid obesity were fall victims. Nine patients had a single injury, two presented an associated serious head injury, one a severe chest injury, and one multiple trauma with coma, chest contusion, and abdominal lesions. One patient had a fracture of the distal femur with associated ischemia. Five knee dislocations were open with a popliteal wound for three and a posteromedial wound for two. Four patients presented total sciatic nerve palsy and nine palsy of the common peroneal nerve. The dislocation was documented in ten cases: lateral (n=1), anterior (n=4), posterior (n=5). For four patients, the dislocation had been reduced during pre-hospital care. Preoperative arteriography was available for eight patients and confirmed the disruption of the popliteal artery; the diagnosis was obvious in six other patients who were directed immediately to the operative theatre without pre-operative imaging. Revascularization was achieved with a upper popliteal-lower popliteal bypass using an inverted saphenous graft. The graft was harvested from the homolateral greater saphenous vein in eight patients and the contralateral vein in six. On average, limb revascularization was achieved after 10.07 hours ischemia. Intravenous heparin was instituted for 810 days followed by low-molecular-weight heparin. The dislocation was stabilized by a femorotibial fixator in nine patients and a cruropedious cast in five. An incision was made in the anterolateral and posterior leg compartments in twelve patients. A revision procedure was necessary on day one in one patient because of recurrent ischemia; a second bypass using an autologous venous graft was successful. One other 75-year-old patient also presented recurrent ischemia on day five; the bypass was reconstructed but the patient died from multiple injuries. Seven thin skin grafts were used to cover the aponeurotomy surfaces. Mean duration of the external fixator was 3.4 months. The five patients treated with a plaster case were immobilized for 2.7 months on average. Ligament repair was performed in three patients (one lateral reconstruction and one double reconstruction of the central pivot for the two others). A total prosthesis with a rotating hinge was implanted in two patients aged 67 and 74 years after removal of the external fixator at six and seven months. Failure of the ligament repair also led to arthroplasty in a third patient.

RESULTS

Blood supply to the lower limb was successfully restored as proven by the renewed coloration of the teguments and-or presence of distal pulses in 13 patients. Transient acute renal failure required dialysis in one patient. Four patients developed pin track discharges and there was one case of septic arthritis of the knee joint which was cured after arthrotomy for wash-out and adapted antibiotics. Outcome was assessed a minimum 18 months follow-up (average 22 months) for the 13 survivors. The three sciatic palsies recovered partially at five and six months in the tibial territory but with persistent paralysis in the territory of the common peroneal nerve. The nine cases of common peroneal nerve palsy noted initially regressed completely or nearly completely in three patients, partially in three and remained unchanged in three. The results were assessed as a function of the final knee procedure: outcome was satisfactory for the patients with a total knee arthroplasty. Outcome of the three ligamentoplasties was good in one, fair in one, and a failure in one (revision arthroplasty). Patients treated by immobilization without a second surgical procedure complained of joint instability with a variable clinical impact; their knee retained active flexion greater than 90 degrees and complete extension.

DISCUSSION

An analysis of the literature and the critical review of our clinical experience was conducted to propose a coherent therapeutic attitude for patients presenting this type of trauma. The prevalence of disruption of the popliteal vascular supply in patients with knee dislocation is between 4 and 20%. The rate is closely related to that of injury to nerves and soft tissue. Ischemia should be immediately suspected in all cases of knee dislocation. The pedious and tibial pulses must be carefully noted before and after reduction of the dislocation to determine whether or not there is an organic arterial lesion. If the pulses are absent initially, they should be expected to reappear strong, rapidly and permanently after reduction. Otherwise, arteriography should be performed. Dislocation stretches the artery between two points of relative anchorage in the adductor ring and the soleus arcade to the point of rupture. Repair requires a bypass between the upper popliteal artery and the tibioperoneal trunk using an inverted saphenous graft because the walls are torn over several centimeters. The traumatology and vascular surgical teams must work in concert from the beginning of the surgical work-up in order to establish a coherent operative strategy founded on primary reduction of the dislocation, installation of a fixator and then vascular repair and aponeurotomy incisions. It would be preferable to wait until the bypass is proven patent and wound healing is complete before proposing ligament repair. This should be done after a precise anatomic work-up to assess each ligament lesion. Bony avulsion or simple disinsertion can however be repaired in the emergency setting at the time of the bypass as well as any ligament rupture which is obvious and-or situated on the medial collateral approach. Secondarily, elements of the central pivot can be repaired in young patients with an important functional demand. Arthroplasty is not warranted except in the elderly patient. Dissection of the popliteal fossa or debridement of the wound enables a careful anatomic assessment of the nerve trunks. In the event of a peroneal nerve disruption, it is advisable to fix the nerve ends to avoid retraction. Beyond three months without clinical or electromyography recovery, surgical exploration is indicated. In the event more than 15 cm is lost, there is no hope for a successful graft. Complete knee dislocation is extremely rare. It can be caused by high-energy trauma associated with several ligament ruptures, particularly rupture of the central pivot observed in 10-25% of cases with common peroneal nerve palsy. Compression, contusion or disruption of the popliteal artery is very rarely caused by the displacement of the femur or the tibia. Limb survival may be compromised. Mandatory emergency restoration of blood supply will modify immediate and subsequent surgical strategies. There has not however been any study exclusively devoted to double joint and vascular involvement. Our objective was to present a critical retrospective analysis of a consecutive series of knee dislocations with ischemia due to disruption of the common popliteal artery treated in a single center and to describe the specific features of management strategies for a coherent diagnostic and therapeutic approach.

[Dislocation and fractures around the knee with popliteal artery injury: A retrospective analysis of 54 cases]

A retrospective multicentric series of 54 cases of knee trauma with acute ischemia by popliteal artery injury were analyzed. These high-energy traumas involved 25 dislocations and 29 fractures, 11 involving distal femur, 15 the proximal tibia and 3 a floating knee. There were 45 men and 7 women, mean age 42 years. Thirty-three patients suffered multiple injuries. The knee injury was open in 25 cases and associated with sciatic paralysis in 32. Vascular repair was almost always achieved with bypass surgery. An external fixator was used in 39 patients. Vascular repair was unsuccessful in three cases requiring amputation, all three cases involving fractures. There were also six secondary amputations due to muscle necrosis or septic nonunion. The rate of complete recovery of the sciatic was 25%. The rate of nonunion was 37%, half due to infection. Outcome assessed at at least one year follow-up was moderate with frequent functional sequelae. The analysis of these results and data reported in the literature provided indications for diagnostic and therapeutic propositions.

Knee dislocation with ipsilateral femoral shaft fracture: a report of five cases

We report the management and outcome of 4 patients with 5 knee dislocations associated with ipsilateral femoral shaft fractures. All patients were managed by immediate reduction of the knee dislocation, intramedullary nailing of the femur, and angiography, followed by postoperative immobilization of the knee (brace or external fixation) for a minimum of 6 weeks. Four of the 5 dislocations underwent a secondary ligament reconstruction. At the 2-year follow up, the mean Knee Society Score was 133 (range 99-170).

Magnetic resonance imaging of the multiple-ligament injured knee

OBJECTIVE

To evaluate magnetic resonance imaging (MRI) and magnetic resonance angiography (MRA) in detecting soft tissue, neurovascular, and bony injury after multiple ligament knee injury, including knee dislocation.

MATERIALS AND METHODS

A retrospective search was performed for patients presenting with reported knee dislocation from May 1993 through May 2000 who underwent both MRI and surgical reconstruction. Twenty-one patients met these criteria (15 men and six women; age range 14 to 75 years; mean 32.6 years). Magnetic resonance diagnoses of soft tissue and bony injury were compared with the patients' operative findings. MRA of the popliteal vessels was performed in seventeen of our twenty-one patients, and the results of these studies are described.

RESULTS

Multiple ligamentous, tendinous, meniscal, chondral, osseous, and neural injuries were seen. There was excellent correlation (kappa > 0.8) between the magnetic resonance and operative findings with regard to the size and location of tears. Regarding meniscal tears, the type (e.g., bucket, radial split, meniscocapsular separation) and location correlated well with surgery. All ten nerve injuries noted on magnetic resonance were confirmed at surgery. Six of our patients had both conventional angiograms and MRAs with 100 percent agreement between the studies. In one patient an intimal flap in the popliteal artery was seen on MRA and confirmed on conventional angiographic images.

CONCLUSION

MRI is an accurate method of assessing soft tissue, osseous, and neural damage after knee dislocation. Our early experience with popliteal fossa MRA is encouraging with complete agreement between the MRA and conventional angiography in patients who had both studies.

Sonographic evaluation of ACL rupture signs compared to arthroscopic findings in acutely injured knees

Evaluation of ultrasound (US) examination for the diagnosis of an acute anterior cruciate ligament (ACL) rupture. We performed a prospective examination of 193 patients to analyze the three indirect criteria of ACL rupture: echo-poor space at the femoral insertion of the ACL, S-shaped course and thickening of the posterior cruciate ligament (PCL) and protrusion of the posterior fibrous capsule. The assumption that the echo-poor space at the femoral insertion has a great significance was confirmed in this study. Sensitivity for ACL rupture was 0.91 and specificity was 0.80, protrusion of the posterior fibrous capsule had a specificity of 0.77 and a sensitivity of 0.68. The use of both criteria increased the sensitivity of sonography to 0.98, but the specificity decreased to less than 0.50. We conclude that the US examination with its three indirect signs of ACL rupture has a high predictive value in the acute traumatized knee joint.