Differences of injury characteristics of medial patellofemoral ligament in acute lateral patellar dislocation and multiligament knee injuries.

BACKGROUND: The injury characteristics of medial patellofemoral ligament (MPFL) in multiligament knee injuries (MLKIs) and the differences of injury patterns of MPFL in MLKIs and acute lateral patellar dislocation (LPD) remain unclear. PURPOSE: To explore the differences of injury characteristics of MPFL after acute LPD and MLKIs. METHODS: Magnetic resonance images were prospectively analyzed in 219 patients after acute LPD or MLKIs. Statistical analyses of the injury patterns of MPFL were performed between LPD and MLKIs. RESULTS: The incidence of partial tear and complete MPFL tear in adolescent LPD and MLKIs were 40.3% and 48.4%, and 27.9% and 16.3%, respectively. Compared with LPD, MLKIs showed lower incidence rates of partial and complete MPFL tears (both P = 0). The MLKI subgroup showed lower incidence rates of MPFL tear at the patellar insertion (PAT), femoral attachment (FEM), and multiple-site of the MPFL (COM) (9.3%, 20.9%, and 14%) when compared with the LPD subgroup (45.2%, 24.2%, and 16.1%) (all P < 0.01). The incidence of partial tear and complete MPFL tear in adult LPD and MLKIs were 41.5% and 47.2%, and 24.6% and 16.4%, respectively. Compared with LPD, MLKIs showed lower incidence rates of partial and complete MPFL tears (both P = 0). The MLKI subgroup showed lower incidence rates of MPFL tear at PAT, FEM, and COM (8.2%, 18%, and 14.8%) when compared with the LPD subgroup (20.8%, 34%, and 30.2%) (all P = 0). CONCLUSION: Compared with LPD, MPFL tears are relatively uncommon in MLKIs. Even if MPFL tears occur, partial tears and femoral-sided tears are relatively more common.

Factors associated with acute articular cartilage lesions of the patella and lateral femoral condyle in acute first-time lateral patellar dislocation: A prospective magnetic resonance imaging study.

OBJECTIVES: To identify risk factors of acute articular cartilage lesions of the patella and lateral femoral condyle in acute first-time lateral patellar dislocation (LPD). METHODS: Magnetic resonance images were prospectively analyzed in 115 patients in an acute first-time LPD. Factors included gender, skeletal maturity, trochlear dysplasia, patellar height, and tibial tuberosity-trochlear groove (TT-TG) distance. Binary logistic regression analysis was carried out to identify the independent risk factors for the incidence of acute articular cartilage lesions of the patella and lateral femoral condyle in acute first-time LPD. RESULTS: The incidence of acute articular cartilage lesion of the patella and lateral femoral condyle were 46.1% and 27% in acute first-time LPD, respectively. Univariate analysis revealed significantly higher incidence rate of acute articular cartilage lesion of the patella in male (P = 0.027), skeletally mature (P = 0.035), normal TT-TG distance (P = 0.043) and normal femoral trochlea (P = 0.031). Risk factors for the incidence of acute articular cartilage lesion of the patella were skeletally mature (odds ratio (OR): 2.324), normal TT-TG distance (OR: 2.824) and normal femoral trochlea (OR: 3.835). Univariate analysis revealed significantly higher incidence rate of acute articular cartilage lesion of the lateral femoral condyle in skeletally mature (P = 0.027) and normal femoral trochlea (P = 0.031). Risk factor for the incidence of acute articular cartilage lesion of the lateral femoral condyle was normal femoral trochlea (OR: 3.347). CONCLUSIONS: For patients in acute first-time LPD, compared with other parameters, the normal femoral trochlea, normal TT-TG distance and skeletally mature are independent risk factors for the incidence of acute articular cartilage lesion of the patella, and the normal femoral trochlea is an independent risk factor for the incidence of acute articular cartilage lesion of the lateral femoral condyle.

Gender-related differences in concomitant articular injuries after acute lateral patellar dislocation.

OBJECTIVES: To explore the gender differences in the concomitant articular injuries after acute lateral patellar dislocation (LPD). METHODS: Magnetic resonance images were prospectively analyzed in 166 patients after an acute LPD. Concomitant articular injuries included bone contusion, medial patellofemoral ligament (MPFL) injury, articular cartilage lesion, and vastus medialis obliquus (VMO) lesion. Statistical analyses were performed between the patient's gender and the incidence of concomitant articular injuries in adolescent and adult subgroups. RESULTS: The incidence of partial and complete MPFL tear in adolescent males and females were (45%, 50%) and (63.2%, 29.8%), respectively. Compared with adolescent females, adolescent males showed higher incidence of complete MPFL tear (P = 0.049). The incidence of articular cartilage lesion of patella in adolescent males and females were 40% and 21.1%, respectively. Compared with adolescent females, adolescent males showed higher incidence of articular cartilage lesion of the patella (P = 0.043). No correlations were identified in other injuries in the adolescent group. The incidence of partial and complete MPFL tear in adult males and females were (34.4%, 65.6%) and (56.8%, 37.8%), respectively. Compared with adult females, adult males showed higher incidence of complete MPFL tear (P = 0.036). The incidence of articular cartilage lesion of patella in adult males and females were 56.3% and 32.4%, respectively. Compared with adult females, adult males showed higher incidence of articular cartilage lesion of patella (P = 0.047). The incidence of VMO injury in adult males and females were 59.4% and 35.1%, respectively. Compared with adult females, adult males showed higher incidence of VMO injury (P = 0.044). No correlations were identified in other injuries in the adult group. CONCLUSIONS: Compared with females, males predispose to complete MPFL tear and articular cartilage lesion of patella after acute LPD. Compared with female adults, male adults predispose to VMO injury.

Diabetic Peripheral Neuropathy Increases Electrical Stimulation Threshold of Sciatic Nerve: A Prospective Parallel Cohort Study.

PURPOSE: To investigate the impact of diabetic peripheral neuropathy and its severity on the threshold of sciatic nerve electrical stimulation in diabetic patients. PATIENTS AND METHODS: The case-control study included 60 patients that were divided into non-diabetic patients (control group, n = 26) and diabetic patients (diabetes group, n = 34). All the patients who were scheduled for lower leg, foot, and ankle surgery received a popliteal sciatic nerve block. We recorded the minimum current required to produce motor activity of the sciatic nerve during ultrasound-guided popliteal sciatic nerve block. RESULTS: Among the 60 patients, the sciatic nerve innervated muscle contractile response was successfully elicited in 57 patients (dorsiflexion of foot, plantar flexion, foot valgus or adduction, toe flexion, etc.) under electric stimulation. We failed to elicit the motor response in three patients with diabetic peripheral neuropathy, even when the stimulation current was 3 mA. The average electrical stimulation threshold (1.0 ± 0.7 mA) in the diabetes group was significantly higher than that of the control group (0.4 ± 0.1 mA). Diabetic patients with peripheral neuropathy had a higher electrical stimulation threshold (1.2 ± 0.7 mA) than patients without peripheral neuropathy (0.4 ± 0.1 mA). Furthermore, the electrical stimulation threshold of the sciatic nerve in diabetic patients had a linear dependence on the Toronto Clinical Scoring System (TCSS) peripheral neuropathy score (electrical stimulation threshold [in mA] = 0.125 TCSS score) (P < 0.001). CONCLUSION: The threshold of electrical stimulation to elicit a motor response of the sciatic nerve was increased in diabetic patients, and the threshold of electrical stimulation of the sciatic nerve increased with the severity of diabetic nerve dysfunction.

Dose-dependent neurotoxicity caused by the addition of perineural dexmedetomidine to ropivacaine for continuous femoral nerve block in rabbits.

OBJECTIVE: This study was designed to evaluate the neurotoxicity of dexmedetomidine combined with ropivacaine for continuous femoral nerve block in rabbits. METHODS: Thirty New Zealand rabbits were randomly divided into 5 groups of 6 rabbits each and received a continuous femoral nerve block with saline; 0.25% ropivacaine; or 1, 2, or 3 µg/mL of dexmedetomidine added to 0.25% ropivacaine (Groups A-E, respectively). Sensory and motor function was assessed after the nerve block. The rabbits were anesthetized and killed after 48 hours of a continuous femoral nerve block, and the femoral nerves were removed for light and electron microscopy analyses. RESULTS: The behavior scores were highest in Group A at 2 and 6 hours after injection. The scores were higher in Groups B and C than in Groups D and E at these same time points. All groups showed normal pathological tissues in the femoral nerves under optical microscopy. Under electron microscopy, histological abnormalities were observed only in Group E; none of the other groups exhibited pathological abnormalities. Quantitative analysis of the myelin sheath area revealed no significant difference in the axonal area, total area of the myelin sheath, or ratio of the total axonal area to the total area of the myelin sheath in all groups. CONCLUSION: The lowest doses of dexmedetomidine (1 and 2 µg/mL) combined with 0.25% ropivacaine for continuous femoral nerve block resulted in no neurotoxic lesions, but the higher dose (3 µg/mL) resulted in neurotoxic lesions in this rabbit experimental model.

Incidence of second-time lateral patellar dislocation is associated with anatomic factors, age and injury patterns of medial patellofemoral ligament in first-time lateral patellar dislocation: a prospective magnetic resonance imaging study with 5-year follow-up.

PURPOSE: To examine the predictors of the second-time lateral patellar dislocation (LPD) in patients after acute first-time LPD in a 5-year follow-up. METHODS: Data were collected prospectively from patients after acute first-time LPD with conservative treatment. Factors included sex, age at the first-time LPD, anatomical variants [trochlear dysplasia, patellar height, tibial tuberosity-trochlear groove (TT-TG) distance], and injury patterns of medial patellofemoral ligament (MPFL) in acute first-time LPD. Logistic regression was carried out to identify the independent risk factors for the incidence of the second-time LPD. RESULTS: The incidence rate of a second-time LPD was 35.5% (59 of 166) in the 5-year follow-up. Univariate analysis revealed significant differences in the incidence rate of the second-time LPD among age at the first-time LPD (P = 0.04), trochlear dysplasia (P = 0.003), patella height (P = 0.017) and the TT-TG distance (P = 0.027). Risk factors for the second-time LPD were age < 18 years at the first-time LPD [odds ratio (OR) 4.088], low-grade trochlear dysplasia (OR 7.214), high-grade trochlear dysplasia (OR 18.945), patella alta (OR 8.416), elevated TT-TG distance (OR 12.742), complete MPFL tear at its isolated femoral-side (OR 6.04) and complete combined MPFL tear (OR 5.851). CONCLUSIONS: Trochlear dysplasia, elevated TT-TG distance, patella alta, age < 18 years at the first-time LPD, complete MPFL tear at its isolated femoral-side and complete combined MPFL tear in the first-time LPD are independently associated with a higher incidence rate of the second-time LPD. LEVEL OF EVIDENCE: III.

The Correlation between the Injury Patterns of the Medial Patellofemoral Ligament in an Acute First-Time Lateral Patellar Dislocation on MR Imaging and the Incidence of a Second-Time Lateral Patellar Dislocation.

Objective: To evaluate the correlation between the injury patterns of the medial patellofemoral ligament (MPFL) on magnetic resonance imaging in an acute first-time lateral patellar dislocation (LPD) and incidence of a second-time LPD. Materials and Methods: Magnetic resonance images were prospectively analyzed in 147 patients after an acute first-time LPD with identical nonoperative management. The injury patterns of MPFL in acute first-time LPDs were grouped by location and severity for the analysis of the incidence of second-time LPD in a 5-year follow-up. Independent t tests, chi-square tests and Kruskal-Wallis tests were performed as appropriate. Results: Forty-six cases (46/147, 31.3%) of second-time LPD were present at the 5-year follow-up. Fourteen (14/62, 22.6%) and 31 cases (31/80, 38.8%) were present in the partial and complete MPFL tear subgroups, respectively. Twenty-five cases (25/65, 38.5%), 11 cases (11/26, 42.3%), and 8 cases (8/47, 17%) were present in the isolated femoral-side MPFL tear (FEM), combined MPFL tear (COM), and isolated patellar-side MPFL tear (PAT) subgroups, respectively. Compared with the partial MPFL tears, complete tears showed higher incidence of a second-time LPD (p = 0.04). The time interval between the two LPDs was shorter in the complete MPFL tear subgroup (24.2 months) than in the partial tear subgroup (36.9 months, p = 0.001). Compared with the PAT subgroup, the FEM and COM subgroups showed a higher incidence of a second-time LPD (p = 0.025). The time intervals between the two LPDs were shorter in the FEM and COM subgroups (20.8 months and 19.2 months) than in the PAT subgroup (32.5 months, p = 0.049). Conclusion: A complete MPFL tear, isolated femoral-side tear and combined tear in a first-time LPD predispose a second-time LPD.

Correlation analysis between injury patterns of medial patellofemoral ligament and vastus medialis obliquus after acute first-time lateral patellar dislocation.

PURPOSE: To evaluate the correlation between injury patterns of the medial patellofemoral ligament (MPFL) and vastus medialis obliquus (VMO) after acute first-time lateral patellar dislocation (LPD) in adults. METHODS: Magnetic resonance imaging (MRI) was prospectively performed in 132 consecutive adults with acute first-time LPD. Images were acquired and evaluated using standardized protocols. Injury patterns of MPFL were grouped by location and severity for analysis of the prevalence of VMO injury. RESULTS: MRI demonstrated VMO injury in 63 (47.7%) patients. Twenty (38.5%) and 43 cases (56.6%) were present in partial and complete MPFL tear subgroups, respectively. Compared with partial MPFL tears, complete tears showed a higher prevalence of VMO injury (P = 0.044). The mean coronal (28.5 mm) and mean sagittal VMO elevations (20.7 mm) were higher in the complete MPFL tear subgroup than in the partial tear subgroup (19.8 mm, P = 0.005; 11.9 mm, P < 0.001). No correlations were identified between the prevalence of VMO injury and location subgroups of MPFL injury (n.s.). Mean VMO elevations were higher in isolated femoral-side (FEM) and combined MPFL tear (COM) subgroups (mean coronal VMO elevation of 29 mm and mean sagittal VMO elevation of 20.8 mm in the FEM subgroup; mean coronal VMO elevation of 29.6 mm and mean sagittal VMO elevation of 23.1 mm in the COM subgroup) than in the isolated patellar-side MPFL tear (PAT) subgroup (P = 0.022, P < 0.001) (mean coronal VMO elevation of 20.7 mm and mean sagittal VMO elevation of 10.6 mm). CONCLUSIONS: Complete MPFL tear predisposes to VMO injury and has a higher elevation of torn VMO after acute first-time LPD in adults. Isolated femoral-side and combined MPFL tears predispose to higher elevation of torn VMO. LEVEL OF EVIDENCE: IV.

Injury patterns of medial patellofemoral ligament after acute lateral patellar dislocation in children: Correlation analysis with anatomical variants and articular cartilage lesion of the patella.

OBJECTIVES: To assess the relationship between injury patterns of medial patellofemoral ligament (MPFL) and anatomical variants and patellar cartilage lesions after acute lateral patellar dislocation (LPD) in children. METHODS: MR images were obtained in 140 children with acute LPD. Images were acquired and evaluated using standardised protocols. RESULTS: Fifty-eight cases of partial MPFL tear and 75 cases of complete MPFL tear were identified. Injuries occurred at an isolated patellar insertion (PAT) in 52 cases, an isolated femoral attachment (FEM) in 42 cases and an isolated mid-substance (MID) in five cases. More than one site of injury was identified in 34 cases. Compared with Wiberg patellar type C, Wiberg patellar type B predisposed to complete MPFL tear (P = 0.042). No correlations were identified between injury patterns of MPFL and trochlear dysplasia, patellar height and tibial tuberosity-trochlear groove distance (P > 0.05). Compared with partial MPFL tear, complete MPFL tear predisposed to Grade-IV and Grade-V patellar chondral lesion (P = 0.02). There were no correlations between incidence of patellar cartilage lesion and injury locational-subgroups of MPFL (P = 0.543). CONCLUSIONS: MPFL is most easily injured at the PAT in children. Wiberg patellar type B predisposes to complete MPFL tear. Complete MPFL tear predisposes to a higher grade of patellar chondral lesion. KEY POINTS: • MPFL is most easily injured at its patellar insertion in children. • Wiberg patellar type B predisposes to complete MPFL tear. • No correlations between injury patterns of MPFL and other three anatomical variants. • Complete MPFL tear predisposes to higher grade patellar chondral lesion. • No correlations between injury locations of MPFL and patellar cartilage lesion.

Injury patterns of medial patellofemoral ligament and correlation analysis with articular cartilage lesions of the lateral femoral condyle after acute lateral patellar dislocation in adults: An MRI evaluation.

OBJECTIVES: The purpose of this study was to investigate the injury characteristics of medial patellofemoral ligament (MPFL), and to analyse the correlations between the injury patterns of MPFL and articular cartilage lesions of the lateral femoral condyle in adults with acute lateral patellar dislocation (LPD). METHODS: Magnetic resonance (MR) images were prospectively obtained in 121 consecutive adults with acute LPD. Images were acquired using standardised protocols and these were independently evaluated by two radiologists. RESULTS: Forty-eight cases of partial MPFL tear and 71 cases of complete MPFL tear were identified. Injuries occurred at an isolated femoral attachment (FEM) in 48 cases, an isolated patellar insertion (PAT) in 36 cases and an isolated mid-substance (MID) in five cases. More than one site of injury to the MPFL (COM) was identified in 30 cases. The prevalence rate of chondral and osteochondral lesions of the lateral femoral condyle were 4.2% (2/48) and 6.3% (3/48) in the FEM subgroup, 19.4% (7/36) and 22.2% (8/36) in the PAT subgroup and 6.7% (2/30) and 13.3% (4/30) in the COM subgroup, respectively. The PAT subgroup showed significantly higher prevalence rate of chondral and osteochondral lesions in the lateral femoral condyle when compared with the FEM subgroup. The prevalence rate of chondral and osteochondral lesions of the lateral femoral condyle were 8.5% (6/71) and 19.7% (14/71) in the complete MPFL tear subgroup and 10.4% (5/48) and 4.2% (2/58) in the partial MPFL tear subgroup, respectively. The subgroup of the complete MPFL tear showed significantly higher prevalence rate of osteochondral lesions in the lateral femoral condyle when compared with the subgroup of the partial MPFL tear. CONCLUSIONS: Firstly, the MPFL is most easily injured at the FEM, and secondly at the PAT in adults after acute LPD. The complete MPFL tear is more often concomitant with osteochondral lesions of the lateral femoral condyle than the partial MPFL tear. The isolated patellar-sided MPFL tear is more easily concomitant with chondral lesions and osteochondral lesions of the lateral femoral condyle than the isolated femoral-sided MPFL tear.

Injury patterns of medial patellofemoral ligament and correlation analysis with articular cartilage lesions of the lateral femoral condyle after acute lateral patellar dislocation in children and adolescents: An MRI evaluation.

OBJECTIVES: The purpose of this study was to investigate the injury characteristics of medial patellofemoral ligament (MPFL), and to analyse the correlations between the injury patterns of MPFL and articular cartilage lesions of the lateral femoral condyle in children and adolescents with acute lateral patellar dislocation (LPD). METHODS: Magnetic resonance (MR) images were prospectively obtained in 127 consecutive children and adolescents with acute LPD. Images were acquired using standardised protocols and these were independently evaluated by two radiologists. RESULTS: Fifty-four cases of partial MPFL tear and 69 cases of complete MPFL tear were identified. Injuries occurred at an isolated patellar insertion (PAT) in 47 cases, an isolated femoral attachment (FEM) in 41 cases and an isolated mid-substance (MID) in four cases. More than one site of injury to the MPFL (COM) was identified in 31 cases. The prevalence rate of chondral and osteochondral lesions of the lateral femoral condyle were 23.4% (11/47) and 29.8% (14/47) in the PAT subgroup, 7.3% (3/41) and 9.8% (4/41) in the FEM subgroup and 25.8% (8/31) and 32.3% (10/31) in the COM subgroup, respectively. The PAT and COM subgroups showed significantly higher prevalence rate of chondral and osteochondral lesions in the lateral femoral condyle when compared with the FEM subgroup. The prevalence rate of chondral and osteochondral lesions of the lateral femoral condyle were 17.4% (12/69) and 30.4% (21/69) in the complete MPFL tear subgroup and 20.4% (11/54) and 13% (7/54) in the partial MPFL tear subgroup, respectively. The subgroup of the complete MPFL tear showed significantly higher prevalence rate of osteochondral lesions in the lateral femoral condyle when compared with the subgroup of the partial MPFL tear. CONCLUSIONS: Firstly, the MPFL is most easily injured at the PAT, and secondly at the FEM in children and adolescents after acute LPD. The complete MPFL tear is more often concomitant with osteochondral lesions of the lateral femoral condyle than the partial MPFL tear. The isolated patellar-sided MPFL tear and the combined MPFL tear are more easily concomitant with chondral lesions and osteochondral lesions of the lateral femoral condyle than the isolated femoral-sided MPFL tear.

Evaluation of medial patellofemoral ligament tears after acute lateral patellar dislocation: comparison of high-frequency ultrasound and MR.

OBJECTIVES: The purpose of this study was to compare the diagnostic performance of high-frequency ultrasound with MR in the evaluation of medial patellofemoral ligament (MPFL) lesions after acute lateral patellar dislocation (LPD). METHODS: High-frequency ultrasound and MR images were prospectively obtained in 97 consecutive patients with acute LPD. Images were acquired using standardised protocols and were independently evaluated by two radiologists. The MPFL was assessed at three sites (patellar insertion, femoral attachment, and mid-substance) for signs of injury. RESULTS: Of a total of 291 sites in 97 MPFLs, 127 showed proven MPFL tear at surgery, including 51 sites of complete tear and 76 sites of partial tear. In a site-based analysis, the sensitivity, specificity, and accuracy of high-frequency ultrasound was 90.8%, 96.3%, and 94.6%, respectively, for partial MPFL tear and 86.3%, 96.3%, and 94%, respectively, for complete tear. For MR, the sensitivity, specificity, and accuracy was 81.6%, 95.7%, and 91.3%, respectively, for partial MPFL tear and 80.4%, 95.7%, and 92.1%, respectively, for complete tear. There was no statistical difference between high-frequency ultrasound and MR in the assessment of partial (P = 0.1, 0.777, 0.155) or complete (P = 0.425, 0.777, 0.449) MPFL lesions. Interobserver agreement was very good for high-frequency ultrasound and good for MR. CONCLUSIONS: Data suggest that high-frequency ultrasound and MR have similar diagnostic performance in the evaluation of MPFL lesions after acute LPD. KEY POINTS: • High-frequency ultrasound and MR were able to detect MPFL lesions after acute lateral patellar dislocation. • High-frequency ultrasound and MR showed similarly high accuracy in diagnosing MPFL lesions. • Interobserver agreement was very good for high-frequency ultrasound and good for MR.

Optimal central venous pressure during partial hepatectomy for hepatocellular carcinoma.

BACKGROUND: Low central venous pressure (CVP) affects hemodynamic stability and tissue perfusion. This prospective study aimed to evaluate the optimal CVP during partial hepatectomy for hepatocellular carcinoma (HCC). METHODS: Ninety-seven patients who underwent partial hepatectomy for HCC had their CVP controlled at a level of 0 to 5 mmHg during hepatic parenchymal transection. The systolic blood pressure (SBP) was maintained, if possible, at 90 mmHg or higher. Hepatitis B surface antigen was positive in 90 patients (92.8%) and cirrhosis in 84 patients (86.6%). Pringle maneuver was used routinely in these patients with clamp/unclamp cycles of 15/5 minutes. The average clamp time was 21.4+/-8.0 minutes. These patients were divided into 5 groups based on the CVP: group A: 0-1 mmHg; B: 1.1-2 mmHg; C: 2.1-3 mmHg; D: 3.1-4 mmHg and E: 4.1-5 mmHg. The blood loss per transection area during hepatic parenchymal transection and the arterial blood gas before and after liver transection were analyzed. RESULTS: With active fluid load, a constant SBP ≥90 mmHg which was considered as optimal was maintained in 18.6% in group A (95% CI: 10.8%-26.3%); 39.2% in group B (95% CI: 29.5%-48.9%); 72.2% in group C (95% CI: 63.2%-81.1%); 89.7% in group D (95% CI: 83.6%-95.7%); and 100% in group E (95% CI: 100%-100%). The blood loss per transection area during hepatic parenchymal transection decreased with a decrease in CVP. Compared to groups D and E, blood loss in groups A, B and C was significantly less (analysis of variance test, P<0.05). Compared with the baseline, the blood oxygenation decreased significantly when the CVP was reduced. Base excess and HCO3- in groups A and B were significantly decreased compared with those in groups C, D and E (P<0.05). CONCLUSION: In consideration of blood loss, SBP, base excess and HCO3-, a CVP of 2.1-3 mmHg was optimal in patients undergoing partial hepatectomy for HCC.

Sonography on injury of the medial patellofemoral ligament after acute traumatic lateral patellar dislocation: Injury patterns and correlation analysis with injury of articular cartilage of the inferomedial patella.

OBJECTIVE: The purpose of this study was to investigate the accuracy of high-frequency ultrasonography in the diagnosis of injuries of medial patellofemoral ligaments (MPFLs), analyse the characteristics of MPFL injury and correlations between injury of the MPFL and articular cartilage of the inferomedial patella in patients with acute traumatic lateral patellar dislocation. METHODS: High-frequency sonographic images of 49 patients with acute traumatic lateral patellar dislocations treated surgically were reviewed. The χ(2) tests were performed for statistical analysis. RESULTS: Twenty-eight cases of complete MPFL tear and 21 cases of partial MPFL tear were identified in operation, with 27 cases of MPFL tear located at their femoral attachment, 21 cases of tear at the patellar attachment and one case of midsubstance tear. The diagnostic accuracy of sonography regarding partial MPFL tear and complete MPFL tear was 89.8% and 89.8%. Among the patients with MPFL tear at the patellar attachment, eight and six cases were concomitant with chondral and osteochondral lesions in the inferomedial patella, respectively, in contrast to nine and six cases in patients with MPFL tear at the femoral attachment, respectively. There was no significant difference between the two locations described above regarding the prevalence rates of chondral or osteochondral lesions of the inferomedial patella (P=0.732, P=0.614). Among the patients with complete MPFL tear, 12 and 10 cases were concomitant with chondral and osteochondral lesions in the inferomedial patella, respectively, while six and two cases were concomitant with partial MPFL tear. There was no significant difference between the two types of injuries discussed above on the prevalence rates of chondral lesions of the inferomedial patella (P=0.305), but the prevalence rate of osteochondral lesions between the two types of injuries discussed above was statistically different (P=0.035). CONCLUSIONS: The MPFL is most easily injured at the femoral attachment, secondly at the patellar attachment. High-frequency ultrasonography is an accurate method in the diagnosis of an MPFL tear. There are neither significant differences on the prevalence rates of chondral or osteochondral lesions of the inferomedial patella between locations of MPFL injuries, nor significant difference on the prevalence rates of chondral lesions between MPFL injury types; but the complete MPFL tear is more often concomitant with inferomedial patellar osteochondral lesions than the partial MPFL tear.