A new classification of injury patterns of the medial patellofemoral ligament after acute lateral patella dislocation detected using magnetic resonance imaging studies

Introduction

Acute lateral patellar dislocation is a very common condition in orthopedics, especially among adolescents and physically active patients. To evaluate distinct medial patellofemoral ligament (MPFL) injury patterns and the associated knee pathology after acute lateral patellar dislocation (ALPD) using magnetic resonance imaging (MRI) studies, which is essential for the development of treatment protocols.

Reconstruction of medial patellofemoral ligament for chronic patellar instability

Background:

Disruption of the capsule, medial patellar retinaculum, and/or vastus medialis obliqus has been associated with recurrent patellar instability. Biomechanical studies have shown that the medial patellofemoral ligament (MPFL) is the main restraint against lateral patella displacement and reconstruction of the MPFL has become an accepted surgical technique to restore patellofemoral stability in patients having recurrent patellar dislocation. We report a prospective series of patients of chronic patellar instability treated by reconstruction of medial patellofemoral ligament.

Materials and Methods:

Twelve patients (15 knees) with recurrent dislocation of patella, were operated between January 2006 and December 2008. All patients had generalised ligament laxity with none had severe grade of patella alta or trochlear dysplasia. The MPFL was reconstructed with doubled semitendinosus tendon. Patients were followed up with subjective criteria, patellar inclination angle, and Kujala score.

Results:

The mean duration of followup after the operative procedures was an average of 42 months (range 24–60 months) 10 knees showed excellent results, 3 knees gave good results, and 2 knees had a fair result. The average patellar inclination angle decreased from 34.3° to 18.6°. The average preoperative Kujala functional score was 44.8 and the average postoperative score was 91.9.

Conclusion:

MPFL reconstruction using the semitendinosus tendon gives good results in patients with chronic patellar instability without predisposing factors like severe patella alta and high-grade trochlear dysplasia, and for revision cases.     

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

ObjectivesTo explore the gender differences in the concomitant articular injuries after acute lateral patellar dislocation (LPD).MethodsMagnetic 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.ResultsThe 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.ConclusionsCompared 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.     

Medial patellofemoral ligament anatomy: is it a predisposing factor for lateral patellar dislocation?

Purpose

Because the medial patellofemoral ligament (MPFL) is the primary restraint to lateral dislocation of the patella, we aimed, in this controlled study, to verify whether the MPFL with different measurements could be considered another predisposing factor for patellar dislocation.

Methods

A group of 100 consecutive individuals without the criteria for patellar dislocation (trochlear dysplasia, patella alta and lateral patellar tilt) was recruited as a control group and underwent magnetic resonance imaging (MRI) study and another group of 50 patients with patellar instability. Femoral condyles, interepicondylar distance, length and thickness of the MPFL were measured.

Results

In the control group, the MPFL was 38–60 mm long. Individuals with patellar instability who had no episode of patellar dislocation had a 4.11-mm longer ligament than controls (p = 0.032), while patients with instability with a previous history of dislocation had a 13.54-mm longer MPFL than controls (p < 0.001). Thickness of the MPFL at the patellar insertion was lower in individuals with patellar instability with a history of dislocation (p < 0.001). An instability coefficient (IC) less than 1.3 indicates that the MPFL is insufficient.

Conclusions

Individuals with patellar instability and previous patellar dislocation present with longer MPFL when compared to controls, and an associated IC less than 1.3 can be considered a predisposing factor for patellar dislocation. Treatment of patellar instability is a challenge, and it is difficult to identify what is the predisposing factor. This study has verified the measurements of the MPFL for the first time and presents values of thickness and length that can be considered as indications for surgical reconstruction.Level of evidence: III.     

Transosseous suturing of patellar fractures with braided polyester – A prospective cohort with a matched historical control study

Background

Although tension-band wiring is the most widely used technique to fix patellar fractures, metal implant-related complications including implant failure and postoperative pain are very common and additional procedures are often necessary to treat the complications. The purpose of this study is to evaluate a totally metal-free technique using a transosseous suturing method and to compare it with the traditional fixation technique.

Method

A total of 25 patients (mean age of 59.60 years) with displaced patellar fractures treated by a transosseous suturing technique were compared with a 1:1 matched historical control group that underwent modified tension-band-wire fixation. Union time, union rate, operation time, number of procedures, mean hospitalisation days and complications were compared between cases and controls.

Results

Union time (8.43 ± 2.92 vs. 8.64 ± 2.82 weeks) and operation time (69.00 ± 19.31 vs. 64.89 ± 14.27 min) were not different between the two groups. Mean hospitalisation days (4.04 ± 1.40 vs. 5.76 ± 1.50 days; P < 0.001), number of procedures and the frequency of complications were significantly lower in the transosseous suturing group.

Conclusion

The transosseous suturing technique is safe and effective in the transverse or comminuted fractures of the patella. The complication rate is significantly lower than with the tension-band-wiring technique.     

Medial Patellofemoral Ligament Reconstruction for Recurrent Patellar Instability Using a Gracilis Autograft without Bone Tunnel

Background

Several tendon graft and fixation methods have been introduced in medial patellofemoral ligament (MPFL) reconstruction for recurrent patellar dislocation. The purpose of this study was to evaluate the results of MPFL reconstruction using a gracilis autograft fixation without bone tunnel in patients with recurrent patellar instability.

Methods

Nine patients (four males and five females) diagnosed with recurrent patellar instability from July 2009 to January 2013 and had MPFL reconstruction using a gracilis autograft were included. The average age of the patients was 24.6 years (range, 13 to 48 years), and the average follow-up period was 19.3 months (range, 12 to 30 months). For every patient, femoral attachment was fixed using suture anchors securing the patella by suturing the periosteum and surrounding soft tissue. Clinical evaluation included the Kujala, Lysholm, and Tegner scores; in addition, patients were examined for any complication including recurrent dislocation. The congruence angle and patella alta were assessed radiologically before and after surgery.

Results

The Kujala score improved from an average of 42.7 ± 8.4 before surgery to 79.6 ± 13.6 (p = 0.008) at final follow-up; the Lysholm score improved from 45.8 ± 5.7 to 82.0 ± 10.5 (p = 0.008); and the Tegner score improved from 2.8 ± 0.8 to 5.6 ± 1.5 (p = 0.007). The Insall-Salvati ratio changed from 1.16 ± 0.1 (range, 0.94 to 1.35) before surgery to 1.14 ± 0.1 (range, 0.96 to 1.29; p = 0.233) at the final follow-up without significance. The congruence angle significantly improved from 26.5° ± 10.6° (range, 12° to 43°) before surgery to -4.0° ± 4.3° (range, -12° to 5°; p = 0.008) at final follow-up. Subluxation was observed in one patient and hemarthrosis occurred in another patient 2 years after surgery, but these patients were asymptomatic.

Conclusions

We achieved good results with a patellar fixation technique in MPFL reconstruction using a gracilis autograft employing soft tissue suturing in patients with recurrent patellar dislocation.     

Sonographic evaluation of the injuries after traumatic patellar dislocation in adolescents

BACKGROUND: Traumatic patellar dislocation (TPD) may be associated with other injuries requiring additional treatment. The superficial localization of the knee extensor apparatus and knee articular cartilage make them accessible to sonographic evaluation (ultrasonography [USG]). PURPOSE OF THE STUDY: Prospective analysis of the value of USG in TPD. METHODS: In 21 patients, 22 knees were examined by USG after clinical and routine radiographic evaluations. Based on USG findings, operative or nonoperative treatment was done (15 and 7 cases, respectively). RESULTS: In 17 knees, lesions of the medial patellofemoral ligament (MPFL) fibers were visible. In 16 knees, avulsion fractures of the patellar insertion of the MPFL were identified. Injuries of the femoral attachment of the MPFL or intramuscular hematoma of the vastus medialis obliquus (VMO) were present in 7 knees. Eleven osteochondral loose bodies and 1 nondisplaced osteochondral fracture were detected in 11 knees. Corresponding osteochondral lesions were localized in all cases. An osteochondral loose body that was identified by USG was confirmed intraoperatively or by computed tomographic scan in 91.6%, the osteochondral lesion localization in 81.8%, and avulsion fracture of the patellar attachment of the MPFL in 100% of knees. Overall, the USG findings were confirmed by these methods in 88.2% of knees. CONCLUSIONS: Ultrasonography is highly efficient in determining the extent of injuries after TPD in adolescents. Ultrasonography allows visualization of loose bodies, localization of osteochondral lesions, and, using a dynamic modification, allows precise assessment of the functional status of the MPFL. LEVEL OF EVIDENCE: II.     

Classification of lesions of the medial patello-femoral ligament in patellar dislocation

The remnants of the medial patello-femoral ligament (MPFL) of 67 knees, 18 with acute patellar dislocation and 49 with chronic patellar dislocation, were studied. The MPFL injuries of the acute cases were categorised into 2 groups: an avulsion tear type and a substantial tear type. The chronic cases were put into 3 groups: those with loose femoral attachment (9 knees), those with scar tissue formation or abnormal scar branch formation (29 knees), and those with no evidence or continuity of the ligament (absent type) (11 knees). It is concluded that incompetence of the medial patello-femoral ligament is a major factor in the occurrence of recurrent patellar dislocation and/or an unstable patella following an acute patellar dislocation.     

Comparing the predictive value of the pelvic ring injury classification systems by Tile and by Young and Burgess

Introduction

Radiology-based classifications of pelvic ring injuries and their relevance for the prognosis of morbidity and mortality are disputed in the literature. The purpose of this study was to evaluate potential differences between the pelvic ring injury classification systems by Tile and by Young and Burgess with regard to their predictive value on mortality, transfusion/infusion requirement and concomitant injuries.

Patients and methods

Two-hundred-and-eighty-five consecutive patients with pelvic ring fractures were analyzed for mortality within 30 days after admission, number of blood units and total volume of fluid infused during the first 24 h after trauma, the Abbreviated Injury Severity (AIS) scores for head, chest, spine, abdomen and extremities as a function of the Tile and the Young–Burgess classifications.

Results

There was no significant relationship between occurrence of death and fracture pattern but a significant relationship between fracture pattern and need for blood units/total fluid volume for Tile (p < .001/p < .001) and Young–Burgess (p < .001/p < .001). In both classifications, open book fractures were associated with more fluid requirement and more severe injuries of the abdomen, spine and extremities (p < .05). When divided into the larger subgroups “partially stable” and “unstable”, unstable fractures were associated with a higher mortality rate in the Young–Burgess system (p = .036). In both classifications, patients with unstable fractures required significantly more blood transfusions (p < .001) and total fluid infusion (p < .001) and higher AIS scores.

Conclusions

In this first direct comparison of both classifications, we found no clinical relevant differences with regard to their predictive value on mortality, transfusion/infusion requirement and concomitant injuries.