Biomechanical evaluation of a second generation headless compression screw for ankle arthrodesis in a cadaver model.

BACKGROUND: Many types of screws, plates, and strut grafts have been utilized for ankle arthrodesis. Biomechanical testing has shown that these constructs can have variable stiffness. More recently, headless compression screws have emerged as an evolving method of achieving compression in various applications but there is limited literature regarding ankle arthrodesis. The aim of this study was to determine the biomechanical stability provided by a second generation fully threaded headless compression screw compared to a standard headed, partially threaded cancellous screw in a cadaveric ankle arthrodesis model. MATERIALS AND METHODS: Twenty fresh frozen human cadaver specimens were subjected to simulated ankle arthrodesis with either three standard cancellous-bone screws (InFix 7.3mm) or with three headless compression screws (Acumed Acutrak 2 7.5mm). The specimens were subjected to cyclic loading and unloading at a rate of 1Hz, compression of 525 Newtons (N) and distraction of 20N for a total of 500 cycles using an electromechanical load frame (Instron). The amount of maximum distraction was recorded as well as the amount of motion that occurred through 1, 10, 50, 100, and 500 cycles. RESULTS: No significant difference (p=0.412) was seen in the amount of distraction that occurred across the fusion site for either screw. The average maximum distraction after 500 cycles was 201.9µm for the Acutrak 2 screw and 235.4µm for the InFix screw. No difference was seen throughout each cycle over time for the Acutrak 2 screw (p-value=0.988) or the InFix screw (p-value=0.991). CONCLUSION: Both the traditional InFix type screw and the second generation Acumed Acutrak headless compression screws provide adequate fixation during ankle arthrodesis under submaximal loads. CLINICAL RELEVANCE: There is no demonstrable difference between traditional cannulated partially threaded screws and headless compression screws studied in this model.

Dislocated Posterior Tibial Tendon Treated With Plate Buttress Fixation in a Collegiate Gymnast: A Case Report and Review of the Literature.

UNLABELLED: Dislocation of the posterior tibial tendon (PTT) is a rare pathological process that occurs most often as a result of acute trauma. The injury involves forced dorsiflexion and eversion of the foot against a contracted posterior tibialis. Diagnosis of the injury is often difficult secondary to the rarity of the injury and its similarity with other benign injuries of the medial ankle. Routine diagnostic imaging often does not reveal the injury, and advanced imaging with magnetic resonance imaging or ultrasound to confirm the diagnosis is often required. The injury can be a result of an abnormal retromalleolar groove or a tear of the flexor retinaculum. Because nonoperative treatment frequently results in poor outcomes with continuing pain and progressive flat foot, operative treatment with repair of the flexor retinaculum with correction of the retromalleolar groove is the most described intervention. We report an acute case of PTT dislocation in a collegiate gymnast during competition and offer our technique for surgical correction in the setting of a partially torn, attenuated flexor retinaculum with plate buttressing of the PTT into its native uncorrected groove. LEVELS OF EVIDENCE: Therapeutic, Level IV: Case study.

Application of biologics in the treatment of the rotator cuff, meniscus, cartilage, and osteoarthritis.

Advances in our knowledge of cell signaling and biology have led to the development of products that may guide the healing/regenerative process. Therapies are emerging that involve growth factors, blood-derived products, marrow-derived products, and stem cells. Animal studies suggest that genetic modification of stem cells will be necessary; studies of cartilage and meniscus regeneration indicate that immature cells are effective and that scaffolds are not always necessary. Current preclinical animal and clinical human data and regulatory requirements are important to understand in light of public interest in these products.

Diagnostic cervical lymphadenectomy in children: a case for multidisciplinary assessment and formal management guidelines.

A retrospective review was carried out of all children under 16 years of age that underwent cervical lymphadenectomy in our department within a 7-year period. The pathway of their referral from the community to hospital care was noted. The circumstances surrounding the decision for surgery, including clinical features of lymph nodes and investigation results were also recorded. We concluded that cervical lymphadenectomy is an uncommon occurrence in children with an incidence of 2.5/100,000 per year and a yield rate of 15.8% for serious conditions requiring treatment. We demonstrate the importance of joint decision-making between surgeons and paediatricians to reduce the rate of unnecessary biopsies. We also reveal the inconsistency in the pre-operative investigation of these children leading to a low number of positive biopsies and highlighting the need for formal management guidelines.

Anatomic landmarks for locating parotid lesions in relation to the facial nerve: cross-sectional radiologic study.

OBJECTIVES: To determine the accuracy of using surrogate anatomic structures radiologically to predict the relation of parotid lesions to the intraparotid facial nerve. SETTING: Tertiary centre. DESIGN: Retrospective. PATIENTS AND METHODS: All patients with parotid masses over a 5-year period who undertook parotidectomy were considered. A radiologist and an otolaryngologist reviewed the images. Their decision regarding the location of the lesions using four surrogate structures was compared with intraoperative documentation. OUTCOME MEASURE: We determined the sensitivity and the specificity of using the external carotid artery, retromandibular vein, posterior belly of the digastric muscle, and tragal pointer. RESULTS: Thirty films were examined (24 magnetic resonance images [MRIs] and 6 computed tomographic [CT] scans). The sensitivity and the specificity of the retromandibular vein were 0.85 and 0.57, respectively, whereas for the external carotid artery, they were 0.94 and 0.3, respectively. It was too impractical to relate the other two structures to the lesions. CONCLUSIONS: The retromandibular vein is the most accurate surrogate structure to use on MRI or CT for predicting the location of a parotid lesion to the facial nerve. However, the substantial proportion of deep lesions misjudged limits the benefit of performing the imaging.