Clinical and radiographic outcomes of the mobility total ankle arthroplasty system: early results from a prospective multicenter study.

BACKGROUND: The Mobility Total Ankle System is a third-generation design consisting of a 3-component, cementless, unconstrained, mobile-bearing prosthesis. This study reports the early results of a prospective multicenter study of the Mobility prosthesis. METHODS: Eighty-eight Mobility total ankle arthroplasties (TAAs) were implanted in 85 patients. The most common underlying diagnosis was posttraumatic arthritis (53%). Ankles were classified according to the Canadian Orthopedic Foot and Ankle Society (COFAS) end-stage ankle arthritis classification system. Coronal plane deformity was quantified preoperatively. Patients were reviewed at regular intervals postoperatively, with clinical and radiographic assessment. The mean follow-up time was 40 months (range, 30-60 months). RESULTS: Type 1 ankle arthritis was demonstrated in 44 ankles (50%). No patient had preoperative coronal plane angulation greater than 20 degrees. In 32 ankles (36%) the preoperative coronal alignment was neutral, and in 34 ankles (39%) the deformity was less than 10 degrees. The mean American Orthopaedic Foot & Ankle Society (AOFAS) Ankle-Hindfoot score improved from 38.2 (range, 12-59) preoperatively to 74.8 (range, 46-100) postoperatively. Bone-implant interface abnormalities were identified in 33 ankles with a retained prostheses (43%). Thirty (91%) of these involved zones around the tibial plate. In total, 8 TAAs required revision, 6 for aseptic loosening, 1 for talar migration, and 1 for deep infection. There was 1 conversion to arthrodesis for component malpositioning and 1 transtibial amputation for chronic regional pain syndrome. Six patients were being investigated for ongoing pain. The cumulative survival was 89.6% (95% confidence interval, 80.8-94.8) at 3 years and 88.4% (95% confidence interval, 79.3-93.9) at 4 years. CONCLUSION: Early results of the Mobility TAA for independent researchers do not match those reported by other surgeons. Good pain relief and improved function were achieved postoperatively in 72 ankles (82%). High rates of bone-implant interface abnormalities around the tibial plate are concerning but require longer follow-up to determine their clinical significance.

Osteosarcoma: A rare cause of painful enlargement of the hallux.

Malignant osseous and soft-tissue tumors of the foot are rare. We report a case of osteosarcoma in the proximal phalanx of the hallux in a 45-year-old man. In patients with foot-related symptoms, a high index of suspicion for pedal osteosarcoma is required. Delayed or inappropriate diagnosis may compromise limb-sparing surgery and survivorship.

Altered signal intensity in the posterior horn of the medial meniscus: an MR finding of questionable significance.

INTRODUCTION: MR imaging has emerged as an important modality in the non-invasive evaluation of osseous and soft-tissue structures in the post-traumatic knee. However, it is sometimes impossible to determine with confidence if a focus of high signal intensity in the meniscus is confined to the substance of the meniscus or if it extends to involve the joint surface. This is a critical differentiation because the latter represents meniscal tears that can be found and treated arthroscopically, whereas the former represents degeneration, intrasubstance tears or perhaps normal variants that are not amenable to arthroscopic intervention. The aim of this study was to investigate the occurrence of such borderline findings in relation to the posterior horn of the medial meniscus and to correlate the arthroscopic results. MATERIALS AND METHODS: Sixty-four patients with suspected post-traumatic internal derangements of the knee who underwent MR imaging prior to arthroscopy were evaluated retrospectively. There were 48 men and 16 women. Their mean age was 28.2 years. RESULTS: Tears of the posterior horn of the medial meniscus were diagnosed unequivocally (grade 3 signal) in 18 patients and equivocally (grade 2/3 signal) in 10 patients. Arthroscopic correlation revealed 16 tears (89%) in the unequivocal group and only 1 tear (10%) in the equivocal group. CONCLUSION: A meniscal tear is unlikely when MR shows a focus of high signal intensity in the posterior horn of the medial meniscus that does not unequivocally extend to involve the inferior or superior joint surface. An appropriate trial of conservative treatment is recommended in such questionable cases. MR is a useful diagnostic tool-however, it should be used selectively, and in conjunction with history and clinical examination in evaluating internal derangements of the knee.

Osteoid osteoma: painful enlargement of the second toe.

Osteoid osteomas involving the phalanges of the toes are a rare occurrence. We report a case of an osteoid osteoma of the distal phalanx of the second toe which was treated successfully with surgical excision. Although soft-tissue swelling with a typical clinical history is suggestive of the diagnosis, differentiation from subacute infection is subtle and may ultimately depend on tissue analysis.

The Web: friend or foe of the hand surgeon?

Healthcare information contained on the World Wide Web is not screened or regulated and claims may be unsubstantiated and misleading. The objective of this study was to evaluate the nature and quality of information on the Web in relation to hand surgery. Three search engines were assessed for information on three hand operations: carpal tunnel decompression, Dupuytren's release and trigger finger release. Websites were classified and evaluated for completeness, accuracy, accountability and reference to a reliable source of information. A total of 172 websites were examined. Although 85% contained accurate information, in 65% this information was incomplete. Eighty-seven per cent of websites were accountable for the information presented, but only 24% made references to reliable sources. Until an organised approach to website control is established, it is important for hand surgeons to emphasise to their patients that not everything they read is complete or accurate. Publicising sites known to be of high quality will promote safe browsing of the Web.

Aneursymal bone cyst of the proximal phalanx of the thumb in a child.

Aneursymal Bone Cysts (ABCs) involving the hand are a rare occurrence. We report a case of an ABC of the proximal phalanx of the thumb in a boy which was treated successfully with curettage and autologous bone grafting. When the diagnosis of ABC of the small bones of the hand is entertained, prompt therapeutic intervention is indicated because of the potential for aggressive local behaviour. In the paediatric patient, simple surgery to preserve the growth plate is recommended.