Cementless total hip replacements in sickle cell disease.

BACKGROUND: Sickle cell disease (SCD) affects around 80,000 people in the USA and 12,000 in the UK. Up to 40% of patients will get osteonecrosis of the femoral head. Cemented acetabular components yield poor results with the rate of osteolysis ranging from 13.5 to 46%. We report on a consecutive cohort of patients with SCD who underwent uncemented THA with ceramic-on-ceramic (CoC) bearings. METHODS: Since 2002 52 primary THAs were carried out in 40 patients. The average age was 36.1 years (17-54). 48 cases had exchange blood transfusion preoperatively and 3 had top-up transfusions.An S-ROM was used in 47 hips a Solutions stem in 4 hips and an AML in 1. It was necessary to drill the femur during 12 hips. There were 5 intra-operative peri-prosthetic fractures. 2 dislocations were observed. 2 superficial infections were detected. RESULTS: All components have in-grown. There have been no cases of radiographic osteolysis, migration or loosening of the hip with average 5-year (2-10.1) follow-up. CONCLUSIONS: The combination of a multidisciplinary team approach and uncemented implants, with ceramic-on-ceramic bearings used, has made THA in patients with SCD a safe and reliable procedure in our hospital.

Fretting and corrosion in modular-neck total hip arthroplasty femoral stems.

BACKGROUND: During total hip arthroplasty, use of a modular femoral neck on a stemmed implant allows optimization of neck anteversion, length, and offset, resulting in more accurate balance. We performed a retrospective analysis of a consecutive cohort of patients who had undergone total hip arthroplasty with a modular-neck hip system with ceramic-on-ceramic bearings. METHODS: We reviewed the results in fifteen patients who had received an ABG II dual modular hip system (Stryker Orthopaedics, Mahwah, New Jersey) from May 2007 to August 2008. Anteroposterior radiographs of the pelvis were reviewed and scored with regard to medial calcar erosion. Magnetic resonance imaging (MRI) was performed to assess for adverse local tissue reaction around the hip joint. Calcar resorption was correlated with subsequent MRI findings. Retrieval analysis was performed on the implants removed at revision. RESULTS: The mean duration of follow-up for all patients was 42.3 months (range, thirty-three to sixty months). Cobalt-ion levels were elevated in all patients; chromium levels were within the normal range. Medial femoral calcar erosion was noted in seven of the fifteen cases. All patients with grade-2 or 3 calcar erosion on radiographs had positive MRI findings consistent with adverse local tissue reaction. At the time of writing, seven patients had undergone revision arthroplasty. Intraoperatively, tissue staining with tissue and bone necrosis and pseudotumor formation were observed in all revision cases. Histological analysis confirmed the presence of metal-on-metal synovitis, with changes similar to those seen with metal-on-metal bearings. CONCLUSIONS: The ABG II dual modular hip system is associated with a high rate of early failure secondary to fretting and corrosion at the femoral neck-stem taper. The component has subsequently been recalled and is no longer in use. Surgeons using modular hip systems with a titanium stem and cobalt-chromium neck should be vigilant about annual follow-up with radiographs, and use of MRIs as indicated.

Limited slot femorotomy for removal of proximally coated cementless stems. A 10-year follow-up of an unreported surgical technique.

We present a technique of single posterior longitudinal slot femorotomy. This technique allows the expansion of the metaphyseal-diaphyseal region of the proximal femur facilitating extraction of proximally coated uncemented femoral components while leaving the metaphysis and diaphysis intact. Since 1996 we have performed this technique in 18 revision total hip arthroplasties in 15 patients who had x-ray appearance of bony in-growth/on-growth and where found to have solidly ingrown stems at revision surgery. All were revised to a metaphyseally fitting uncemented stem. At mean follow-up of 122.4 months, there were significant improvements in both pain and function. All revised stems achieved stable boney fixation. There were no complications due to this technique. No patient developed a limp or thigh pain postoperatively. There have been no re-revisions of the stem. With appropriate patient selection, this is a simple, reliable, and extensile technique is useful to assist in the extraction of uncemented proximally coated femoral components whether hydroxyapatite-coated or not.

The surgical anatomy of intra-abdominal prosthetic dislocation during hip arthroplasty.

Hip replacement surgery remains one of the most successful and common operations in modern orthopaedics. Many surgical approaches to the hip have been described. A potential anatomical weakness exists between the hip joint and the retroperitoneal space. We describe this potential space, which lies superficial to iliopsoas and its importance in hip replacement surgery. The clinical relevance of this space is illustrated by 2 cases of retro-peritoneal migration of prosthetic femoral heads and the consequences of these.

A case report of three peripheral schwannomas attached to the Achilles paratenon.

BACKGROUND: Schwannomas are uncommon slow growing tumours arising from the nerve sheath or Schwann cell. OBJECTIVE: To report a case of multiple schwannomas arising form the achilles paratenon. METHODS: A 38 year old man presented lumps on the dorsum of his leg. He was clinically evaluated, subjected to imaging studies and surgery. RESULTS: 3 separate lumps where removed measuring 10, 12, and 12mm. They here confirmed to be schwannomas on hitochemical staining. CONCLUSION: A schwannoma must be considered in the differential of lumps in the lower leg. This is the first report of schwanommas associated with the paratenon. Removal of such masses is warranted to prevent local erosion.

Post-operative stress fractures complicating surgery for painful forefoot conditions.

A stress fracture is caused by repetitive or unusual loading of a bone leading to mechanical failure. Fatigue type stress fractures occur in normal bone exposed to abnormally high repetitive loads, whereas insufficiency type stress fractures occur in abnormal bone exposed to normal loads. We describe three cases of insufficiency stress fractures that have complicated surgery for painful forefoot conditions. The diagnosis and management of these cases are discussed. Stress fractures should be included in the differential diagnosis of any patient who continues or develops pain after surgery to the forefoot.