Anatomical variations in the insertion of the peroneus (fibularis) longus tendon.

BACKGROUND: Multiple pathologies are associated with the peroneus longus tendon including traumatic injury, tendinitis, tenosynovitis, dislocation, acute rupture, chronic tear, and avulsion fractures. While the description of insertion points for the peroneus longus tendon exists in numerous texts and articles, none are consistent in describing the incidence of variation of the insertional slips. METHODS: Dissection was performed on the feet of 30 adult, embalmed cadaver limbs disarticulated at the knee and ankle joint. RESULTS: All 30 specimens had a consistent attachment to the base of the first metatarsal by a strong band. A slip to the medial cuneiform was observed in 26 specimens (86.6%). The anterior and posterior frenular ligaments were present in 25 (83.3%) and four (13.3%) specimens, respectively. Another thick and strong fibrous band, termed additional band (AB), was observed close to the metatarsocuneiform joint in nine specimens (30%). Additional slips to the neck of first metatarsal, bases of second, fourth, and fifth metatarsals also were noted. CONCLUSIONS: We have described the incidences of variations of the insertion of the peroneus longus tendon and an additional band, which gives rise to various muscles. CLINICAL RELEVANCE: The results of this study may be important to better understand the symptoms associated with peroneus longus tendon pathologies and the role played by the peroneus longus tendon in maintaining the arch of the foot.

Partial Resurfacing for Humeral Head Defects Associated With Recurrent Shoulder Instability.

Recurrent traumatic shoulder instability is a complex clinical entity that commonly affects young, active patients. Humeral head defects are frequently associated with this condition, but specific treatment to stabilize the shoulder is rarely needed. Management options for defects of the humeral head that do necessitate treatment carry various risks and disadvantages, including the need for bone or soft tissue healing, complications related to hardware, and loss of motion. Partial prosthetic resurfacing has been reported as a treatment option. The current study retrospectively reviewed a cohort of patients with recurrent or locked anterior and posterior instability who underwent partial prosthetic humeral head resurfacing for significant Hill-Sachs and reverse Hill-Sachs lesions. At an average of 36.4 months after the index procedure, 16 patients were contacted by mail and telephone. Of the study group, 13 patients underwent partial resurfacing for anterior instability and 3 patients underwent partial re-surfacing for posterior instability. No patient had a repeat dislocation. In addition, 77% of patients in the anterior instability cohort and all of the patients in the posterior instability cohort returned to their full preinjury activity level. For the anterior instability cohort, significant improvements from preoperatively to final follow-up occurred for mean Musculoskeletal Review of System score (4.54, P<.0001) and Short Form-12 physical component score (9.52, P=.002). For the combined cohort, the Penn Shoulder Score improved by 36.4 points (P=.059). This study showed the effectiveness of partial humeral head resurfacing for preventing redislocation for patients with significant Hill-Sachs and reverse Hill-Sachs lesions. [Orthopedics. 2017; 40(6):e996-e1003.].

Mapping of cartilage depth in the knee and elbow for use in osteochondral autograft procedures.

BACKGROUND: Osteochondritis dissecans (OCD) of the elbow is a problematic condition that affects a fair number of young athletes. One treatment option is the use of osteochondral autografts, which are commonly taken from donor sites on the less weightbearing surfaces of the knee. PURPOSE: To use magnetic resonance imaging (MRI) to assess the cartilage depths of sites in the knee and elbow that are commonly used as donor and recipient sites to optimize depth matching for osteochondral autograft procedures. STUDY DESIGN: Descriptive laboratory study. METHODS: All knee and elbow MRI scans acquired from 3-T machines in patients aged 16 to 25 years within a single hospital system were reviewed. Studies were excluded if there had been previous surgery on the joint or if there were significant chondral defects in the areas to be measured. All cartilage depth measurements were independently performed by 3 different physicians to the nearest 0.01 mm. At the elbow, 6 locations on the capitellum and 2 on the trochlea were chosen. At the knee, 4 locations along the anterior-lateral femoral condyle, 5 surrounding the intercondylar notch, and 1 on both the medial- and lateral-posterior femoral condyles were chosen. RESULTS: There were 111 knee MRI (74 male, 37 female) and 94 elbow MRI (85 male, 9 female) scans that met all inclusion criteria. The average cartilage depths from each investigator were then averaged to provide an overall mean depth at each location. All average cartilage depths within the knee were thicker than those in the elbow, where the averaged mean thickness of all the 8 measured sites was 1.27 mm (range, 0.78-1.63 mm). Within the knee, the thinnest areas of cartilage, and therefore closest matches, were discovered at the posterior pole of the medial femoral condyle (mean ± SD, 1.95 ± 0.46 mm) and at the distal-most anterior-lateral femoral condyle (1.85 ± 0.46 mm). The average variance between the mean cartilage depths measured by each investigator for each location was 0.12 mm in the elbow and 0.22 mm in the knee. CONCLUSION: Average cartilage depths in the knee were thicker than those in the elbow at all sites measured. The thinnest areas in the knee were the posterior aspect of the medial femoral condyle and the distal-most aspect of the anterior-lateral femoral condyle. CLINICAL RELEVANCE: This study provides the surgeon with meaningful data on average cartilage depths at common donor sites in the knee and recipient sites in the elbow.

Diagnosis of medial tubercle fractures of the talar posterior process using oblique views.

Fracture of the medial tubercle of posterior process of talus is a very rare injury. Often, these fractures are not seen on the AP and lateral radiographs of the ankle joint resulting in them being misdiagnosed as an ankle sprain. This study examines 10 ankle specimens simulated with a posteromedial fracture in varying planes, by multiple X-ray views in varying angles of external rotation in order to increase the sensitivity of oblique views to diagnose a fracture of the posteromedial tubercle. True AP and lateral views (0 degrees and 90 degrees of external rotation) of the ankle joint were unable to detect the fracture simulated in the posteromedial tubercle of the posterior process in any specimens. The fractures in all the specimens were clearly visible when the X-ray beam was parallel to the plane of osteotomy. The fractures could still be identified when the plane of X-ray beam was within +/-10 degrees from the plane of osteotomy. Any further increase or decrease in plane of the X-ray beam could not identify the fracture. Two oblique views at 45 degrees and 70 degrees of external rotation could identify the fractures of the posteromedial tubercle at all planes. These oblique views can be used before resorting to the CT scan.

The role of Pax-6 in lens regeneration.

Pax-6 is a master regulator of eye development and is expressed in the dorsal and ventral iris during newt lens regeneration. We show that expression of Pax-6 during newt lens regeneration coincides with cell proliferation. By knocking down expression of Pax-6 via treatment with morpholinos, we found that proliferation of iris pigment epithelial cells was dramatically reduced both in vitro and in vivo, and, as a result, lens regeneration was significantly retarded. However, induction of dedifferentiation in the dorsal iris was not inhibited. Pax-6 knockdown early in lens regeneration resulted in inhibition of crystallin expression and retardation of lens fiber induction. Once crystallin expression and differentiation of lens fibers has ensued, however, loss of function of Pax-6 did not affect crystallin expression and lens fiber maintenance, even though the effects on proliferation persisted. These results conclusively show that Pax-6 is associated with distinct early events during lens regeneration, namely control of cell proliferation and subsequent lens fiber differentiation.