Depression is a common co-morbidity in Total Hip Arthroplasty (THA). Chronic pain and depression influence one another. Postoperative outcomes and satisfaction rates are affected by depression. The aim of the study was to determine the impact of pre-operative depression on patient functional outcomes and satisfaction rates after THA. A secondary objective was to assess potential change in the incidence of depression at mid-term post-operative follow-up.Introduction
Objectives
The prevalence of immunocompromised patients undergoing Total Hip Arthroplasty (THA) is increasing worldwide as a consequence of advances in treatment. HIV is presenting in an older population group and concerns of higher rates of infection, early failures and dangers posed to healthcare workers exist. This study is imperative to predict future burden of THA and make subsequent provisions The objective was to determine the seroprevalence of HIV in patients presenting for THA in an academic institution in a developing country. Secondarily, the aim was to determine if there is any difference in the seroprevalence of patients undergoing THA and TKA and finally to assess the status of disease control in seropositive patients eligible for TJA on pre-existing HAART.Background
Objectives
Total Hip Replacement (THR) is a proven and effective surgical procedure. One of the main limiting factors of the longevity of THR is the performance of the bearing surface. The optimum bearing surface choice, however, remains controversial. We wanted to understand what influenced the choice of bearing surfaces amongst South African orthopaedic surgeons. We also wanted to know if there was any consensus between surgeons and the orthopaedic trade. There is no epidemiological registry-based data available in South Africa in respect of bearing surfaces used in hip replacements. We sent out an electronic survey to all members of the South African Orthopaedic Association as well as to trade representatives. Patient parameters influencing the choice of bearing surfaces were surveyed and these included age, gender, level of activity and diagnosis. We used a regressional and tree analysis methodology to interpret the results.Introduction:
Aims, material and methods:
Antibiotic prophylaxis prior to dental and other procedures when patients have joint replacements in situ remains controversial. Recommendations seem to generally be intuitive and not based on any sound scientific evidence. Recently, the American Academy of Orthopaedic Surgeons altered their previous standpoint and suggested that orthopaedic surgeons review their current practice of routine prescription of antibiotic prophylaxis. We conducted an electronic survey of members of the South African Orthopaedic Association to determine the opinion of the average orthopaedic surgeon in South Africa in respect of this prophylaxis. 111 surgeons responded.Background:
Method:
Massive acetabular defects remain an unresolved challenge in revision arthroplasty surgery of the hip. We report on 7 patients treated with custom made acetabular components to manage these massive boney defects. After high resolution CT scans were done, custom made implants were designed in collaboration between the surgeons and the manufacturer. All implants matched the bony defects as designed.Background:
Methods:
We report on a series of long-stemmed femoral components used in revision total hip replacements which fractured, and were subsequently revised. All explanted stems were analysed in respect of the reasons for failure. The patient's serial radiographs and clinical records were also analysed. All stems demonstrated some fixation distally. They all showed little proximal osteo-integration. A biomechanical analysis confirmed the vulnerability of these long stemmed modular prostheses in respect of mechanical failure. The resultant unprotected lever-arms led to local stresses in the prosthesis constructs which were above the failure threshold resulting in prosthesis fractures. These fractures all occurred at points where the prostheses were structurally most vulnerable.Methods
Results
Antibiotic loaded polymethyle methacrylate spacers are commonly used in the management of septic hip replacements. The aim of this study was to determine wear patterns on the articulating surfaces of these spacers, as well as to determine the extent of PMMA particulate debris generation.Introduction
Aim
Metal ion levels are used to track the performance of metal containing bearings in hip replacement patients. Changes in whole blood metal ion levels are indicators of wear rates in these bearings. Normal metal ion levels are variable, and range widely. Changes in these “non-bearing” levels over a period of time may influence the monitoring of these bearings. As part of a prospective randomised trial of different bearing surfaces, whole blood metal ion levels were monitored. This included four cohorts of patients, namely ceramic-on-ceramic (CoC), ceramic-on-polyethylene (CoP), ceramic-on-ceramic (CoC) and ceramic-on-metal (CoM). Serial whole blood metal ion levels in the non-metal bearings, namely CoC and CoP, were analyzed. There was no consistency in these whole blood metal ion levels. Intra-patient variations in these levels over a period of time could not be due to bearing-produced metal ions as these were all metal free, and thus not the source of any endogenous ions. These intra-patient variations may reflect changes in exogenous exposure to these metal ions, fluctuations in these patient's metabolic functions or production of metal ions from non-bearing prosthetic sources.Methods.
Results.
To look at the difference in metal ion levels using Ceramic on Metal (COM) and Metal on Metal (MOM) bearings in Total Hip Replacements, comparing the results between well placed and poorly placed cups. Metal ion levels using the ICP-MS method of assay have been studied as part of a prospective randomised trial between 4 different bearing combinations. The ion levels have been raised in the COM and MOM bearings. Metal ions are not raised in the Ceramic on Ceramic (COC) and Ceramic on X linked Poly(COP) bearings, showing that no other material in the study prosthesis aside from the bearing surfaces contribute to raised ion levels. Cup inclination and cup anteversion has been measured in all patients.Purpose of Study:
Methods:
The advantages of computer navigated total knee replacement are well documented in the literature, however, increased surgical time and cost issues remain the major deterrent for the wide use of this technology. Placement of cutting jigs under computer guidance forms a major aspect of computer assisted knee replacement surgery. The use of a motorized mini-robotic cutting jig allows for a more precise and time efficient execution of the femoral cuts under computer guidance. We present a preliminary report on our experience using standard computer assisted surgery (CAS) jigs and mini robotic motorized jigs in computer navigated knee replacement We compared our experience using standard jigs and mini-robotic jigs in knee replacement. A cohort of patients involved in a study comparing navigated and standard total knee replacements received TKA using a Bi-Cruciate Stabilised Knee System. A pilot cohort of patients received total knee replacement using standard computer navigation by the pi galileo system without the mini-robots while awaiting acquisition of the mini robot system. We compared our experience using the same pi galileo system with mini robotic cutting jigs to the cohort without the mini-robotic cutting guides. Reduction in surgical time was statistically significant when using the motorized mini robotic jigs. Blood loss was identical in both cohorts, and cut precision was better in the cohort with the motorized mini robotic jigs.Methods:
Results:
Monitoring the performance of hip replacements post-operatively is tedious and costly, necessitating radiological examinations as well as other specialized examinations such as whole blood metal ion levels. In an effort to control escalating costs, we conducted an ethically approved clinical trial to assess the efficacy of basic acoustic monitoring equipment to asses these implants. An electronic stethoscope was successfully used to record sounds from the hips of participants with different bearing surfaces. The sounds were recorded while conducting a standardized movement sequence. A 5th order Savitzky-Golay filter with a window width of 21 points was used to remove background noise. The recordings were also listened to by ear and three primary classes of sounds were identified. Frequency components contained in the classes were identified using spectrograms and Welch power density spectra. The sounds were correlated with different patient factors including component positioning, BMI and length of time that the implant was in situ. The skewness and kurtosis of the power spectra were calculated and found to be different for each class. Further frequency analysis was conducted with the aid of the discrete wavelet transform. This met with some success as different frequency levels were found in each sound class. All bearing surfaces produced some noise. The most sounds were produced by the ceramic-on-metal group, even though not in the audible range, and those participants with a body mass index in the obese range. Sounds were also detected in the ceramic-on-polyethylene implants. However, no consistent links between these factors and the sounds produced could be identified. Specifically, the lack of correlation between sound occurrence and length of implantation indicates that this technique is not useful in predicting possible failures or future complications in real time.Method.
Results.
The search for the ideal bearing surface in Total Hip Replacements continues. The current ‘best’ materials are felt to be combinations of metal, ceramics and cross-linked polyethylene. Laboratory studies suggest that ceramic-on-metal articulations may provide distinct advantages. This study aims to identify the best bearing surface combination with the lowest adverse side effect profile. Between February 2004 and September 2007, 164 hips were replaced in 142 patients. 39% were male and 69% were female. The average age at surgery was 53 years (17-72 years). Follow-up assessment included radiographs, the Harris Hip Score and whole blood samples for metal ion levels. Complications to date included 3 hips which needed femoral revision because of surgery related factors, and 3 cases of sepsis of which 1 settled and 2 needed revision. One hip needed revision of head and liner to a larger bearing size for recurrent dislocations, and is no longer being followed up for blood metal ions. Post-operative whole blood metal ion levels were compared to pre-operative levels to determine the increase or decrease in metal ion levels. There were no changes in those patients with ceramic-on-ceramic and ceramic-on-polyethylene articulations. Moderately raised whole blood metal ion levels were noted at 3 months in the ceramic-on-metal group, while the metal-on-metal group show the greatest increase. This study agrees with laboratory bearing surface wear studies demonstrating lower wear rates in the ceramic-on-metal group compared to the metal-on-metal group. With concerns related to high blood metal ion levels in metal-on-metal articulations, ceramic-on-metal bearing surfaces may well become a bearing surface of choice in the future, but progress needs to be monitored in the longer term.
The combination of a ceramic head articulating against a metal acetabular liner (CoM) has shown reduced metal ion levels compared with a metal-on-metal bearing (MoM) in hip simulator studies. A randomized prospective clinical trial was undertaken using CoM and MoM bearings in an otherwise identical total hip procedure. The initial clinical results were encouraging. This report comprises a further review of metal ion data. Patients received identical components with the exception of the bearing surface material but all were 28mm diameter. All components were supplied by DePuy International Ltd. Patients were assessed pre-operatively, 3m, 12m and >
24m (median 32m). Whole blood samples were collected at regular follow-ups, frozen and analysed in batches using high resolution Inductively Coupled Plasma – Mass Spectrometry (ICP-MS). All recruited patients are included irrespective of outcome. However some patients failed to attend specific follow-ups and some contaminated samples had to be discarded. Statistical significance was analyzed using a non-parametric comparison (Mann-Whitney test). After 3m and 12m implantation there were between 21 and 24 patients available for analysis in both the CoM and MoM cohort and after >
24m point 10 and 9 respectively. There were four outliers (either Cr or Co >
10ug/l) in both the CoM and MoM groups. In common with previous studies (with the exception of two marginal outliers), these were related to component position. They were implanted with either a cup abduction angle of >
55°, an anteversion angle of >
30° or both. Other studies with the same design of component have reported no significant outliers. The median Cr and the Co levels are lower with the CoM bearing compared with the MoM at all measurements points following implantation. The median background (pre-operative) levels for the combined CoM and MoM group were Cr: 0.22ug/l and Co: 0.49ug/l. These were significantly different (p=0.006). In the CoM group, the median 12m Cr and Co values were 0.43ug/l and 0.72ug/l respectively. The comparable values for MoM are 0.68ug/l and 0.83ug/l. Increases in metal ion levels from pre-operative levels are used as the primary ion level outcome in this study because the background level will comprise of the order of 30–50% of the overall value. The increase in Cr for CoM and MoM from pre-op levels to 12m significantly different for Cr (p=0.015). It has a lower significance for combined metal ion levels (p=0.029). This difference in not significant for Co (p=0.195). In agreement with predictions from hip simulator studies, CoM bearings in this study produced lower levels of metal ions than comparable MoM bearings at all time points. However the difference is less than that predicted in the laboratory and is much more pronounced with Cr than with Co.
Recurrent patellar dislocation is a relatively common disorder in young patients. Historically, treatment options have been based on the underlying disorder predisposing the patient to the dislocation. This has resulted in various soft tissue reefing procedures, patella tendon realignment procedures and boney realignment procedures. Further research has shown that the medial patello-femoral ligament (MPFL) is the primary restraint to lateral patella subluxation and dislocation. Many authors have published their successful treatment of recurrent patella dislocation by reconstruction of the medial patellofemoral ligament. The most widely used is autologous semitendinosis tendon grafts, as well as synthetic materials, and MPFL reconstructions may be combined with boney procedures. Varieties of fixation techniques have been described involving both the patella and femoral sides. We present a technique of MPFL reconstruction using the autologous ipsilateral quadriceps tendon. Our technique avoids the morbidity associated with semitendinosis graft harvesting and the drill holes in, and potential resulting fracture of, the patella. The technique is also simple and is associated with decreased procedure costs. We present the technique and a series of six patients (seven knees) with follow up ranging from eight months to nine years. The average age of patients at the time of surgery 16 to 28 years (mean = 20 years). There have been no redislocations. The median Kujala patellofemoral knee score at follow up was 97 out of 100 (Range 69–100). The results compare very favorably to published results using other techniques. Our technique of reconstructing the MPFL is reliable, produces good results using an objective knee score, and is cost effective. Seventy staff members participated from a potential pool of approximately one hundred staff on duty at the time. Of the seventy staff who participated in this research project a total of three staff members were within 50 mls of the correct amount for each of the three samples. Overall staff were very poor at estimating blood loss. Staff working in the operating theatre, no matter what their affiliation or years of experience, are not accurate when estimating blood loss spilt into a patients bed. A tool that aids in blood loss estimation is a valuable addition to the theatre resource manual.
Dislocations remain a significant problem, especially after revision hip surgery. Revision of components, particularly in elderly patients with co-morbidities, can be fraught with complications. The surgeon’s options are sometimes restricted, particularly when the acetabular and femoral components are well fixed. Increased head lengths are often utilised to increase tissue tension, and thus improve stability. As a niche solution we have designed a low cost modular femoral neck extender. They are manufactured from medical grade Cobalt-Chrome, conforming to ISO 200, CE mark and EN46001 standards. Available in three incremental lengths and with different connecting Morse tapers, increases in effective neck lengths of up to 49 mms can be achieved. When both the original acetabular and femoral components are well orientated, the resultant increased tissue tension imparts stability to the hip. We present a series of five patients where we have used a femoral neck extender to achieve stability of a total hip replacement. Four patients had had multiple previous dislocations. One patient was unstable at the time of revision surgery because of a high hip centre. The average age of the patients was 72 years, and the number of previous dislocations averaged four. The average follow-up after surgery was 22 months. No patients have redislocated their hips. We present our novel femoral neck extenders as an elegant and cost effective solution to convert an unstable hip to a stable hip, especially when the patient has well fixed and orientated components not in themselves requiring revision.
A randomised prospective study of four bearing surfaces in hip replacements is being conducted. The primary objective is to identify the best long term bearing surf ace clinically and radiographically, and metal ion levels have been measured in all cases. Patients have been randomised to the four bearing surfaces viz. Ceramic-on-XLinked Polyethelene, Ceramic-on-Ceramic, Metal-on-Metal and Ceramic-on-Metal. Pre-operative blood samples and follow-up blood samples for metal ion analysis using ICP-MS method have been taken in all patients. As at February 2008 187 patients have been recruited, and metal ion levels at one year are available in 52 patients. Metal ion levels are not increased with Ceramic-on-XLPE or Ceramic-on-Ceramic bearings. At one year follow-up the metal ion levels in Ceramic-on–Metal bearings is half that of Metal-on-Metal bearings using mean levels, and one third using median levels. Of note is that chromium levels in Ceramic-on-Metal bearings is the least elevated. Due to the laboratory evidence that ceramic-on-metal bearings have the best surf ace wear characteristics with no head stripe wear on a ceramic head, and the laboratory and clinic al evidence of lower metal ion levels, Ceramic-on-Metal hip replacements could be one of the bearing surfaces of the future.
Recurrent patellar dislocation is a relatively common disorder in young patients. Historically, treatment options have been based on the underlying disorder predisposing the patient to the dislocation. This has resulted in various soft tissue reefing procedures, patella tendon realignment procedures and boney realignment procedures. Further research has shown that the medial patellofemoral ligament (MPFL) is the primary restraint to lateral patella subluxation and dislocation. Many authors have published their successful treatment of recurrent patella dislocation by reconstruction of the medial patellofemoral ligament. The most widely used is autologous semitendinosis tendon grafts, as well as synthetic materials, and MPFL reconstructions may be combined with boney procedures. Varieties of fixation techniques have been described involving both the patella and femoral sides. We present a technique of MPFL reconstruction using the autologous ipsilateral quadriceps tendon. Our technique avoids the morbidity associated with semitendinosis graft harvesting and the drill holes in, and potential resulting fracture of, the patella. The technique is also simple and is associated with decreased procedure costs. We present the technique and a series of 6 patients (7 knees) with follow up ranging from 8 months to 9 years. The average age of patients at the time of surgery 16–28 years (mean = 20years). There have been no redis-locations. The median Kujala patellofemoral knee score at follow up was 97 out of 100 (Range 69–100). The results compare very favourably to published results using other techniques. Our technique of reconstructing the MPFL is reliable, produces good results using an objective knee score, and is cost effective.
Dislocations remain a significant problem, especially after revision hip surgery. Revision of components, particularly in elderly patients with co-morbidities, can be fraught with complications. The surgeon’s options are sometimes restricted, particularly when the acetabular and femoral components are well fixed. Increased head lengths are often utilized to increase tissue tension, and thus improve stability. As a niche solution we have designed a low cost modular femoral neck extender. They are manufactured from medical grade Cobalt-Chrome, conforming to ISO 200, CE mark and EN46001 standards. Available in 3 incremental lengths and with different connecting Morse tapers, increases in effective neck lengths of up to 49 mm can be achieved. When both the original acetabular and femoral components are well orientated, the resultant increased tissue tension imparts stability to the hip. We present a series of 5 patients where we have used a femoral neck extender to achieve stability of a total hip replacement. 4 patients had had multiple previous dislocations. 1 patient was unstable at the time of revision surgery because of a high hip centre. The average age of the patients was 72 years, and the number of previous dislocations averaged 4. The average follow-up after surgery was 22 months. No patients have redislocated their hips. We present our novel femoral neck extenders as an elegant and cost effective solution to convert an unstable hip to a stable hip, especially when the patient has well fixed and orientated components not in themselves requiring revision.
Whole blood metal ion levels remain a concern in those patients undergoing total hip replacement with metal bearing surfaces. The determination of baseline reference levels are essential if useful information can be gleaned from in vivo studies of functioning implants. We set out to prospectively determine chromium and cobalt metal ion concentrations in patients undergoing total hip replacement to determine reference levels of these metal ions. 100 patients with normal renal function, no occupational or environmental exposure to cobalt and chromium, and an absence of implanted metals were recruited into the study. Metal ion levels were determined using two different assay methods. Both ICP-MS (Inductively Coupled Plasma Mass Spectroscopy) and GFAAS (Graphite Furnace Atomic Adsorption Spectroscopy) are well recognised analytical techniques for the quantification of trace elements. Levels were correlated with gender, age and place of residence. There was considerable variability in whole blood metal ion levels, with the ICP-MS being more sensitive and consistent than the GFAAS method. Direct comparison of concentration levels determined by the two methods revealed no significant correlation. There was no correlation with age, gender and place of residence. Our findings would favour the use of the ICP-MS to determine reference levels and as a baseline for metalion surveillance pre-operatively in patients undergoing metal-on-metal total hip replacements. We also determined that changes in whole blood metal ion levels are more significant than actual levels in patients who have undergone total hip replacement.
