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ABSTRACT: We report a case of impingement in a metal-onmetal total hip replacement causing both notching of the femoral stem neck and aseptic loosening of the acetabular component. The acetabular component was inserted in excessive anteversion. The femoral stem and acetabular components were retrieved. A larger femoral head was used, and an acetabular component was placed in a less anteverted position. Intra-operative testing through different ranges of movement is recommended to identify potential impingement.
Journal of orthopaedic surgery (Hong Kong) 04/2013; 21(1):113-6.
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ABSTRACT: BACKGROUND: The lower limb osteometry of Chinese differs from that of whites. The joint line of the knee in the coronal plane in Chinese is more medially inclined and the posterior condylar angle of the distal femur in the axial plane is larger. However, it is unclear whether there is any direct association between the coronal plane and axial plane osteometry. QUESTIONS/PURPOSES: We asked whether the joint line obliquity of the knee is related to the posterior condylar angle of the distal femur in young Chinese subjects. METHODS: Ninety-nine young Chinese patients with anterior cruciate ligament injuries were recruited. The lower limb alignment and joint line obliquity were measured using standing long radiographs of the whole lower limb. The rotational alignment of the distal femur was assessed in the axial cuts of the MRI. RESULTS: The distal femur rotational alignment was associated with the obliquity of the knee in Chinese. The posterior condylar angle was 5° ± 2°. The knee was 5° ± 3° medially inclined. CONCLUSIONS: The joint line of the knee in a group of young Chinese patients was more medially inclined than that of whites. The posterior condylar angle of the distal femur was larger. The presence of an association between distal femur rotational alignment and joint line obliquity in this group of young Chinese patients suggests a possible developmental cause explaining the difference in osteometry between races.
Clinical Orthopaedics and Related Research 11/2012; · 2.53 Impact Factor
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ABSTRACT: To compare total knee arthroplasty (TKA) patients who received continuous femoral nerve block (FNB) with local anaesthetics through a catheter versus patient-controlled analgesia (PCA) with intravenous morphine.
50 women and 10 men aged 51 to 84 years with matched characteristics underwent TKA and received either continuous FNB with local anaesthetics through a catheter (n=30) or PCA with intravenous morphine (n=30). None of the patients had had previous knee surgery. All operations were performed according to the standard protocol. Daily mean pain numerical rating scale at rest (NRS-R) and during movement (NRS-M), requirement of extra pain control, complications related to pain control, and overall patient satisfaction in both groups were compared.
Both groups were similar in terms of pain NRS-R and NRS-M, overall satisfaction, and length of hospital stay. Within each group, pain NRS-M score was significantly higher than pain NRS-R score. In the FNB group, 3 patients had dislodgement of the femoral catheter on day 1 and switched to PCA with intravenous morphine. Two of them had fair satisfaction. Patients in the PCA group had significantly more side-effects (nausea, vomiting, dizziness, and pruritis); 2 of the 5 patients with nausea and vomiting had fair satisfaction. No patients had any surgical complication.
Both FNC and PCA provide reliable pain control.
Journal of orthopaedic surgery (Hong Kong) 04/2012; 20(1):23-6.
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ABSTRACT: Bone deficiency hinders implant alignment and stabilisation of the bone-implant interface in revision total knee arthroplasty (TKA). Treatments for bone defects include bone cement, bone cement with screw reinforcement, metal augments, impaction bone grafts, structural allografts, and tantalum, depending on the location and size of the defects. Small defects are usually treated with cement, cement plus screws, or impaction allograft bone. Large defects are repaired with structural allografts or metal augments. Recent developments involve the use of highly porous osteoconductive tantalum. We reviewed the pros and cons of each method for bone defect management in revision TKA.
Journal of orthopaedic surgery (Hong Kong) 04/2012; 20(1):78-86.
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ABSTRACT: There are several classification systems for bone defects in revision total knee arthroplasty. Each has its own drawbacks, and none satisfies all the clinical demands. Therefore, a new classification system and treatment guideline based on a combination of criteria (location, side, containment, and severity of the bone defect) is necessary.
Journal of orthopaedic surgery (Hong Kong) 08/2011; 19(2):238-43.
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ABSTRACT: To review the epidemiology of total knee arthroplasty for primary osteoarthritis and the change of patient characteristics over the last decade.
Retrospective review.
A tertiary referral centre for joint replacement surgery in a teaching hospital in Hong Kong.
All patients who underwent primary total knee arthroplasty for primary knee osteoarthritis from January 2000 to December 2009.
In all, 1157 total knee arthroplasties (589 left and 568 right) were performed on 588 females and 162 males. The annual number of total knee arthroplasties increased from 91 in 2000 to 181 in 2009. The annual number of patients increased from 58 (46 female, 12 male) in 2000 to 159 (117 female, 42 male) in 2009. When compared yearly results, there were no significant changes in the preoperative Knee Society Knee Score, Knee Society Functional Assessment, and passive range of motion of these patients. However, there was a significant decreasing trend with regard to lower limb mechanical axis mal-alignment, from 15.1° deviation from the neutral axis in 2000, to 14.8° deviation in 2004, and then 12.9° deviation in 2009 (mostly varus deformity). There was no difference between left knees and right knees, and between females and males. The mean age of the patients did not show significant change over the past decade, but the number and proportion of patients over 80 years old showed an increase from 4.8% (2000 to 2004) to 13.8% (2005 to 2009). On the other hand, the number and proportion of patients under the age of 60 years did not change.
There was an increasing trend towards total knee arthroplasties, both in terms of number of operations and patients. The number of younger patients having total knee arthroplasty did not increase over the last 10 years, whereas the number of those older than 80 years increased significantly over that period.
Hong Kong medical journal = Xianggang yi xue za zhi / Hong Kong Academy of Medicine 02/2011; 17(1):20-5.
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ABSTRACT: To review the latest evidence on antibiotic prophylaxis for patients with total joint replacements to prevent prosthesis infections.
Literature search of Medline and PubMed until June 2009.
Studies of patients with total joint replacements from around the world, studies concerning antibiotic prophylaxis, as well as chemoprophylaxis guidelines from orthopaedic associations were searched.
Literature review, original articles, case reports, best practice guidelines.
With the rising incidence of patients with total joint replacements, subsequent deep infection of the implants is a rare but dreaded complication which has immense physiological, psychological, financial, and social implications. Guidelines from urologists, gastroenterologists, and dental surgeons attempt to identify high-risk patients who may be more susceptible to prosthetic joint infections. These patients are provided with prophylactic antibiotics before any invasive procedure that may cause bacterial seeding to prosthetic joints. Most orthopaedic associations around the world adopt a similar policy to provide prophylaxis to cover any anticipated chance of bacteraemia. The American Association of Orthopaedic Surgeons adopts the most cautious approach in which all patients with total joint replacements who undergo any procedure that breaches a mucosal surface receive prophylactic antibiotics.
The guidelines from the American Association of Orthopaedic Surgeons seem to have an all-encompassing policy when it comes to providing prophylactic antibiotics. Nonetheless, physicians must still exercise their judgement and customise the treatment to each patient. The benefits of prophylactic antibiotics must be balanced against the risks of drug side-effects and the emergence of antibiotic resistance.
Hong Kong medical journal = Xianggang yi xue za zhi / Hong Kong Academy of Medicine 12/2009; 15(6):458-62.
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ABSTRACT: Seventy-four total hip arthroplasties using a cementless acetabular component without holes for supplemental screw fixation were evaluated during a follow-up period of 2-6 years. Immediate full weight-bearing walking was allowed after the operation. A comparison of anteroposterior (AP) radiographs of the pelvis taken in the early postoperative period and when the patient returned for the final follow-up revealed that there was no migration of the acetabular component. Based on the early postoperative radiographs and using the zones described by Martell et al. [J Bone Joint Surg (1993) 75-A:554-571], gaps between the acetabular component and the bone occurred at zone A2 in three hips (4.1%), at zone B1 in 12 hips (16.2%), and at zone B2 in seven hips (9.5%). The final follow-up radiographs, however, revealed only one hip to have a gap of 1.1 mm at zone B2; the majority of the gaps had disappeared. The results suggest that immediate weight-bearing walking did not result in the migration of the cementless acetabular component.
International Orthopaedics 07/2007; 31(3):293-6. · 2.03 Impact Factor
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ABSTRACT: To review the outcome of revision hip arthroplasty using extensively coated femoral components.
We reviewed the results of revision involving 24 extensively porous-coated cementless femoral components in 23 patients, whose mean age was 52.4 years (range, 28.0-79.0 years). Most revisions were performed for aseptic loosening of the previously cemented femoral component. All patients were followed up for a minimum period of 24.0 months (mean, 61.1 months).
Of the 24 femoral stems, 20 showed bone ingrowth, 3 showed stable fibrous ingrowth, and one was unstable because of deep infection. Intra-operative anterior femoral diaphyseal perforation occurred in 2 hips during the insertion of straight femoral components of 200 mm. Postoperative radiographs displayed marked cortical erosion in 3 other hips and cortical perforation in one.
The results from the use of extensively coated femoral components were promising. Nevertheless, anterior cortical perforations were also common, which may be related to more bowing of the femora among the Chinese patients. Caution must be exercised when inserting a long, straight, extensively coated femoral component.
Journal of orthopaedic surgery (Hong Kong) 01/2005; 12(2):168-72.
