Hip precautions following total hip arthroplasty (THA) limits flexion, adduction and internal rotation, yet these precautions cause unnecessary psychological stress. This study aims to assess bony and implant impingement using virtual models from actual patient's bony morphology and spinopelvic parameters to deduce whether hip precautions are necessary with precise implant positioning in the Asian population. Individualized sitting and standing sacral slope data of robotic THAs performed at two tertiary referral centers in Hong Kong was inputted into the simulation system based on patients’ pre-operative sitting and standing lumbar spine X-rays. Three-dimensional dynamic models were reconstructed using the Stryker Mako THA 4.0 software to assess bony and implant impingement both anteriorly and posteriorly, with default cup placement at 40° inclination and 20° anteversion. Femoral anteversion followed individual patient's native version. A 36mm hip ball was chosen for all cups equal or above 48mm and 32mm for those below. Anterior impingement was assessed by hip flexion and posterior impingement was assessed by hip extension. 113 patients were included. At neutral rotation and adduction, no patients had anterior implant impingement at hip flexion of 100°. 1.7% had impingement at 110°, 3.5% had impingement at 120°, 9.7% had impingement at 130°. With 20° of internal rotation and adduction, 0.8% had anterior implant impingement at hip flexion of 90°, 7.1% had impingement at 100° and 18.5% had impingement at 110°. With the hip externally rotated by 20°, 0.8% of patients had posterior implant impingement, and 8.8% bony impingement at 0° extension. With enabling technology allowing accurate component positioning, hip precautions without limiting forward flexion in neutral position is safe given precise implant positioning and adequate osteophyte removal. Patients should only be cautioned about combined internal rotation, adduction with flexion.
Isolated acetabular liner exchange with a highly crosslinked polyethylene (HXLPE) component is an option to address polyethylene wear and osteolysis following total hip arthroplasty (THA) in the presence of a well-fixed acetabular shell. The liner can be fixed either with the original locking mechanism or by being cemented within the acetabular component. Whether the method used for fixation of the HXLPE liner has any bearing on the long-term outcomes is still unclear. Data were retrieved for all patients who underwent isolated acetabular component liner exchange surgery with a HXLPE component in our institute between August 2000 and January 2015. Patients were classified according to the fixation method used (original locking mechanism (n = 36) or cemented (n = 50)). Survival and revision rates were compared. A total of 86 revisions were performed and the mean duration of follow-up was 13 years.Aims
Methods
The aim of this study was to evaluate the survival of a collarless, straight, hydroxyapatite-coated femoral stem in total hip arthroplasty (THA) at a minimum follow-up of 20 years. We reviewed the results of 165 THAs using the Omnifit HA system in 138 patients, performed between August 1993 and December 1999. The mean age of the patients at the time of surgery was 46 years (20 to 77). Avascular necrosis was the most common indication for THA, followed by ankylosing spondylitis and primary osteoarthritis. The mean follow-up was 22 years (20 to 31). At 20 and 25 years, 113 THAs in 91 patients and 63 THAs in 55 patients were available for review, respectively, while others died or were lost to follow-up. Kaplan-Meier analysis was performed to evaluate the survival of the stem. Radiographs were reviewed regularly, and the stability of the stem was evaluated using the Engh classification.Aims
Methods
In total knee arthroplasty (TKA), both intravenous (IV) and/or intra-articular (IA) administration of tranexamic acid (TXA) were showed to reduce blood loss. Moreover, research suggesting TXA decreases postoperative knee swelling, but it is unknown whether this results in improved postoperative rehabilitation outcome. Thus, the aim of this study was to evaluate whether combined IV and IA administration of TXA would associate with improved early rehabilitation outcomes. In this institutional review board approved randomized controlled trial, 179 patients scheduled for unilateral TKA were randomized to one of three regimens: (1) IA administration of 1gm TXA at end of procedure only, (2) additional preoperative IV dose of 15 mg/kg 30min before tourniquet inflation, and (3) additional postoperative dose 4hrs after preoperative dose. Primary outcomes included knee range of motion, Knee Society Score (KSS) at 6-month postoperatively, haemoglobin drop at day-2 post-operatively, and transfusion rate. Secondary outcome was venous thromboembolism (VTE) complications. Baseline characteristics were comparable between the allocation groups. Patients in regimen (3) showed statistically significant better knee extension range (6.2°, 5.9°, 2.9°, p=0.01), and KSS (88.5, 89.9, 93.0, p=0.02) at 6-month postoperatively, and lesser drop in haemoglobin at day-2 post-operatively (2.72, 2.47, 1.75 g/dL, p=0) when compared with patients in other regimens. No patients required transfusion, or complicated by VTE. The combined administration of IA and IV TXA, including both preoperative and postoperative doses, associated with statistically significantly improved early rehabilitation outcomes. The improvement may be related to higher haemoglobin level and decreased knee swelling in patients having regimen (3). For any reader queries, please contact
We investigated whether strontium-enriched calcium
phosphate cement (Sr-CPC)-treated soft-tissue tendon graft results
in accelerated healing within the bone tunnel in reconstruction
of the anterior cruciate ligament (ACL). A total of 30 single-bundle
ACL reconstructions using tendo Achillis allograft were performed
in 15 rabbits. The graft on the tested limb was treated with Sr-CPC,
whereas that on the contralateral limb was untreated and served
as a control. At timepoints three, six, nine, 12 and 24 weeks after
surgery, three animals were killed for histological examination.
At six weeks, the graft–bone interface in the control group was
filled in with fibrovascular tissue. However, the gap in the Sr-CPC
group had already been completely filled in with new bone, and there
was evidence of the early formation of Sharpey fibres. At 24 weeks,
remodelling into a normal ACL–bone-like insertion was found in the
Sr-CPC group. Coating of Sr-CPC on soft tissue tendon allograft
leads to accelerated graft healing within the bone tunnel in a rabbit
model of ACL reconstruction using Achilles tendon allograft. Cite this article:
Arthrodesis of the hip has been employed since the late 19th century. Late complications can arise decades after fusion in patients who were previously asymptomatic. We describe two patients who developed pain in the hip many years after a successful fusion. There was no infection or loosening of the implants. After careful investigation, including oblique radiographs and diagnostic injections of local anaesthetic, the pain was found to be caused by protrusion of the implant. Subsequent removal of the device resulted in complete resolution of the symptoms.
We have investigated the errors in the identification of the transepicondylar axis and the anteroposterior axis between a minimally-invasive and a conventional approach in four fresh-frozen cadaver knees. The errors in aligning the femoral prosthesis were compared with the reference transepicondylar axis as established by CT. The error in the identification of the transepicondylar axis was significantly higher in the minimal approach (4.5° of internal rotation,
