Magnetic Resonance Imaging to Investigate the Clinical Applicability of the Medial Femoral Trochlea Osteochondral Flap Within the Wrist

Background: The medial femoral trochlea (MFT) osteochondral flap is employed for reconstruction of unsalvageable scaphoid proximal pole nonunions. The convex surface of the cartilage-bearing proximal trochlea is used to replace the similarly contoured proximal scaphoid and articulate with the concave scaphoid fossa of the radius. A magnetic resonance imaging (MRI) comparison of the shape of the MFT as it relates to the native proximal scaphoid has not been previously performed. Our study aimed to quantifiably compare the shape of the MFT, proximal scaphoid, and scaphoid fossa. Methods: Using imaging processing software, we measured radius of curvature of the articular segments in MRI scans of 10 healthy subjects’ wrists and knees. Results: Compared with the scaphoid fossa, average ratio of the radius of circumference of the proximal scaphoid was 0.79 and 0.78 in the coronal and sagittal planes, respectively. Compared with the scaphoid fossa, average ratio of the radius of circumference of the MFT was 0.98 and 1.31 in the coronal and sagittal planes, respectively. The radius of curvature of the MFT was larger than the proximal scaphoid, in the coronal and sagittal planes. In the coronal plane, the MFT radius of curvature is nearly identical to the scaphoid fossa, a closer match than the scaphoid itself. In the sagittal plane, the radius of curvature of the MFT was larger than the radius of curvature of the scaphoid fossa. Conclusions: Our data suggest that the radius of curvature, in the sagittal and coronal planes, of the MFT and proximal scaphoid is disparate.

Primary hypertrophic osteoarthropathy and bilateral transient lateral patellar dislocation in an adolescent

This case report is of the index case of bilateral transient patellar dislocation in a patient with primary hypertrophic osteoarthropathy. Primary hypertrophic osteoarthropathy is a rare complex disorder with variable presentation and thus frequently delayed diagnosis. Notably this disease has multiple skeletal manifestations and, of relevance to this case, a proportion of patients suffer from osteitis. Our patient had serial imaging of the knee joints demonstrating osteitis and associated alteration of the femoral trochlea morphology, predisposing to bilateral transient lateral patellar dislocation. The patient’s clinical presentation, diagnosis and management are discussed. Classification of the disease and its diagnostic parameters are summarised along with key imaging features amongst various imaging modalities.

Chondral and Soft Tissue Injuries Associated to Acute Patellar Dislocation: A Systematic Review

Introduction: Chondral and soft tissue injuries can be associated with first time patellar dislocation, but it is unclear how common they are, and which tissues are affected. A systematic review of the literature was performed to investigate the frequency, location, and extent of chondral and medial patellofemoral ligament (MPFL) injuries in patients following first time patellar dislocation. Methods: This systematic review was conducted according to the PRISMA guidelines. PubMed, Google Scholar, Embase, and Web of Science databases were accessed in November 2021. All the published clinical studies reporting the frequency, location, and extent of soft tissue lesions following first time patellar dislocation were accessed. Studies reporting data on habitual, congenital, or recurrent patellofemoral instability were excluded. Results: Data from 42 articles (2254 patients, mean age 21.6 ± 7.3 years) were retrieved. Ninety-eight percent of patients who experienced first time patellar dislocation demonstrated MPFL rupture at MRI. Forty-eight percent of MPFL ruptures were located at the patellar side, 34% at the femoral insertion site, and 18% in the midportion. Eighty-five percent of patients showed signs of patellar chondral damage at MRI, and trochlear chondral injuries were evidenced in 47% of patients. Intra-articular loose bodies were observed in 11.5% of patients. At arthroscopy, the medial facet and the crest of the patella more commonly exhibited chondral lesions than the lateral facet and femoral trochlea. Conclusions: Most patients suffer chondral damage and MPFL tears following after a first time patellar dislocation.

The SP-ET Index is a New Index for Assessing The Vertical Position of Patella

Background. There were some parameters in previous studies did not better reflect the vertical position of the patella relative to the femoral trochlear. The purposes of this study were to assess the value of the most superior point of patella - entrance of femoral trochlea distance ratio (SP-ET index) as a newer index in defining the vertical position of patella relative to the trochlea, correlate it with the Insall-Salvati ratio, and investigate the effect of the new index on chondromalacia patella. Methods. A total of 99 knees of 77 patients with chondromalacia patella were retrospectively analyzed using magnetic resonance imaging (MRI) data from our database. The Insall–Salvati ratio and SP-ET index were measured on MR images. There were 99 knees just with meniscus rupture were enrolled as the control group. The two parameters of the chondromalacia patella were compared with those of the control group. Results. The Insall–Salvati ratio and SP-ET index in the chondromalacia patella group were significantly higher than those in the control group (p < 0.001). The SP-ET index showed a moderate positive correlation with the Insall–Salvati ratio (r=0.307, p<0.001). Receiver operating characteristic (ROC) analysis showed the diagnostic efficiency of the SP-ET index was better than that of the Insall–Salvati ratio in patients with chondromalacia patella. Conclusion. The SP-ET index may be a useful complement parameter to define the vertical position of the patella relative to the femoral trochlear. Increased of the SP-ET index may be an important risk factor for chondromalacia patella.

What Is the Relationship Between the Breech Presentation and Femoral Trochlear Dysplasia? An Experimental Study of the Breech Presentation Model in Neonatal Rats

Background: The relationship between breech presentation and trochlear dysplasia had been confirmed. However, the pathological process of breech-related trochlear dysplasia remain unclear. This study aimed to establish an animal model to simulate breech presentation and to analyze the pathological process of the femoral trochlea.Materials and Methods: One hundred and twenty neonatal rats were randomly assigned into a control group and two experimental groups that were swaddled (using surgical tape) to keep the hip flexed and knees extended to simulate human breech presentation for the 5 days (short Swaddling) and the 10 days (prolonged Swaddling) of life. Gross and cross-sectional observation, histological staining measurement in two experimental time points (5, 10 days after birth) were conducted to evaluate the morphological changes of the femoral trochlea.Results: The incidence of trochlear dysplasia increased with the Swaddling time. Rats in the prolonged Swaddling group had the high prevalence of trochlea dysplasia (52 of 60), followed by short Swaddling group (42 of 60). Gross and cross-sectional observation showed a shallower trochlea groove in two experimental groups. Histologicalstaining measurement indicated that the trochlear sulcus angle and trochlear sulcus depth were significantly different between the experimental group and the control group since day 5 and day 10. Conclusion: In this model, breech presentation had a adverse influence on neonatal knees and could induce trochlear dysplasia. What is more, this study also showed that the more time in breech presentation, the more incidence of trochlear dysplasia.

Medial femoral trochlea flap reconstruction versus proximal row carpectomy for Kienböck’s disease: a morphometric comparison

Surgical options for advanced Kienböck’s disease include proximal row carpectomy or lunate reconstruction with a medial femoral trochlea osteochondral flap. This study compares morphology of the proximal capitate and the medial femoral trochlear surfaces to the proximal lunate using three-dimensional geometric morphometric analysis. Virtual articular surfaces were extracted from MRI studies of ten healthy volunteers. Distances between corresponding points on the proximal lunate and proximal capitate or medial femoral trochlear surfaces were measured. In seven subjects, mean inter-surface distance for the medial femoral trochlea–proximal lunate pair was significantly lower than the proximal capitate–proximal lunate pairing. In three subjects, mean proximal capitate–proximal lunate distance was significantly lower. We conclude that the medial femoral trochlear flap was anatomically closer to the shape of the proximal lunate in the majority of the examined subjects. However, we found that in three out of ten cases, the proximal capitate was a better match.

The free vascularized lateral femoral trochlea osteochondral graft: a reliable alternative for Stage III Kienböck’s disease

Lunate reconstruction using a lateral femoral trochlea osteochondral graft was carried out in 27 patients with Stage III Kienböck’s disease from 2012 to 2019. Twenty-three of these patients could be followed-up in this retrospective study. Ten were women and 13 men. Nine were Lichtman Stage IIIA, seven Stage IIIB and seven Stage IIIC. The mean follow-up was 39 months (range 12–86). Bony consolidation was found in 18 of the 23 patients, with no graft loss. The mean Disabilities of the Arm, Shoulder and Hand score (DASH score) was 11 and the Modified Mayo Wrist Score was 83. There were only two radiological deteriorations, with the same or improved Lichtman classifications in the other patients and a significant reduction in pain. Postoperative extension of the wrist (52°) and flexion (48°) were comparable with preoperative values and, respectively, 81% and 72% of the contralateral side. Grip strength and pinch grip were 32 kg and 12 kg, 88% and 94% of the other hand, respectively, and an insignificant increase compared with the preoperative values. The vascularized lateral femoral trochlea osteochondral graft yields good short- and mid-term results in Grade III Kienböck’s disease. Level of evidence: IV

Inferior Patella Dislocation due to Impaction in the Femoral Trochlea

Acute inferior dislocation of the patella is a rare presentation in trauma and orthopaedics. Type II is caused by direct upward force on the inferior pole of the patella when the knee is flexed impacting the superior pole osteophyte into the intercondylar notch. Impaction in the femoral trochlea is rarely reported. A 92-year-old lady presented with locked knee held in 85° of flexion with an abnormal knee contour. Radiographs demonstrated that the upper pole of the patella was impacted in the femoral trochlea with a fracture of a superior pole osteophyte. The extensor mechanism was intact. Closed reduction is achieved under strong opioid pain relief. The patient returned to her baseline knee function within 6 weeks. Closed reduction of an inferior patellar dislocation in elderly patients is aided by superior pole osteophyte fracture and facilitates early mobilization, and avoidance of general anaesthesia.