Clinics in diagnostic imaging (163). Transient lateral patellar dislocation with trochlear dysplasia

Medial Patellofemoral Ligament Reconstruction: A Comparison of Single-Bundle Transpatellar Tunnel and Double-Anchor Anatomic Techniques for the Treatment of Recurrent Lateral Patellar Dislocation in Adults

PURPOSE

To compare the stability and clinical outcomes of 2 medial patellofemoral ligament reconstruction (MPFLR) techniques for the treatment of recurrent lateral patellar dislocation in adults.

METHODS

Ninety-one patients with recurrent patellar dislocation were randomly divided into 2 groups, undergoing either the traditional single-bundle transpatellar tunnel technique (group A) or the double-anchor anatomic reconstruction technique (group B). Preoperatively and at follow-up, the patellar position and rotation were evaluated by computed tomography with the congruence angle, lateral patellar angle, patellar tilt angle, and lateral patellar translation; the subjective symptoms and functional outcomes were evaluated with Kujala, Lysholm, Tegner, and International Knee Documentation Committee subjective scores. Clinical examinations were also performed, and redislocations or episodes of instability were recorded.

RESULTS

Patients were followed up for a mean period of 41.11 ± 7.40 months (range, 29-62 months). At the final point, no recurrent patellar dislocations occurred, except in 4 patients with instability symptoms in group A; however, no significant difference between the 2 groups was seen (χ² = 2.503, P = .114). The measurement results from computed tomography decreased significantly to the normal range, and no significant difference was found between the 2 groups except for the lesser patellar tilt angle in group B (t = 2.175, P = .030). The clinical examination improved significantly, no patient exhibited a positive apprehension test in either group, and the number of patients with abnormal lateral patellar translation grade and firm end point showed no statistically significant differences between the 2 groups (P > .05). All score systems significantly improved with no significant difference between the 2 groups except for the higher Kujala score (t = -40.635, P = .001) and International Knee Documentation Committee score (t = -33.823, P = .003) in group B.

CONCLUSIONS

Both MPFLR techniques achieved good results in the treatment of patellar dislocation. Compared with the single-bundle transpatellar tunnel technique, the double-anchor anatomic MPFLR technique may be more effective with a more congruous patellofemoral joint and better knee function.

LEVEL OF EVIDENCE

Level II, prospective comparative study.

Clinics in diagnostic imaging (185)

A 20-year-old National Serviceman presented with left knee pain and swelling after training for his physical fitness test. Lateral knee radiography and magnetic resonance (MR) imaging showed patellar tendon-lateral femoral condyle friction syndrome (PT-LFCFS), on a background of patella alta and patellar malalignment. The patient was treated non-operatively with a course of physiotherapy and given advice on rest and activity modification. PT-LFCFS is a less well-recognised but important cause of anterior knee pain and represents an entity in a spectrum of disorders related to patellofemoral instability. We herein discuss the MR imaging findings specific to and associated with this condition, as well as briefly describing treatment options. In addition, we showcase a range of commonly encountered abnormalities that affect the infrapatellar fat pad and briefly discuss their specific MR imaging findings.