Abstract

Aims

The coronavirus disease (COVID)-19 pandemic forced an unprecedented period of challenge to the NHS in the UK where hip fractures in the elderly population are a major public health concern. There are approximately 76,000 hip fractures in the UK each year which make up a substantial proportion of the trauma workload of an average orthopaedic unit. This study aims to assess the impact of the COVID-19 pandemic on hip fracture care service and the emerging lessons to withstand any future outbreaks.

Introduction

The mortality and serious side effects risk of both medical and surgical management of hip and knee osteoarthritis (OA) has been widely published. To date however, there are no studies comparing safety between the two treatment modalities. We aimed to systematically review the published evidence on the mortality and serious complications risk of the various treatments for hip and knee OA.

Introduction

Acetabular revision for cavitary defects in failed total hip replacement remains a challenge for the orthopaedic surgeon. Bone graft with cemented or uncemented revision is the primary solution; however, there are cases where structural defects are too large. Cup cage constructs have been successful in treating these defects but they do have their problems with early loosening and metalwork failure.

Recently, highly porous cups that incorporate metal augments have been developed to achieve greater intra-operative stability showing encouraging results.

Introduction

Increased accuracy of pre-operative imaging in patient-specific instrumentation (PSI) can result in longer-term savings, and reduced accumulated dose of radiation by eliminating the need for post-operative imaging or revision surgery. The benefits and drawbacks of CT vs MRI for use in PSI is a source of ongoing debate. This study reviews all currently available evidence regarding accuracy of CT vs MRI for pre-operative imaging in PSI.

Background

Sterile Surgical Helmet System (SSHS) are used routinely in hip and knee arthroplasty in order to decrease the risk of infection. It protects surgeon from splash and also prevents contamination of surgical field from reverse splash by virtue of its perceived sterility. A prospective study was conducted to confirm if SSHS remain sterile throughout the procedure in Hip (THA) and Knee (TKA) Arthroplasty. We also evaluated if type of theatre had any effect on degree of contamination.

The Oxford Knee Score (OKS) is a valid and reliable self-administered patient questionnaire that enables assessment of the outcome following total knee replacement (TKR). There is as yet no literature on the behavioral trends of the OKS over time. Our aim is to present a retrospective audit of the OKS for patients who have undergone TKR during the past ten years.

We retrospectively analysed 3276 OKS of patients who had a primary TKR and had been registered as part of a multi-surgeon, outcome-monitoring program at St. Helier hospital. The OKS was gathered pre-operatively and post-operatively by means of postal questionnaires at annual intervals. Patients were grouped as per their age at operation into four groups: 60, 61-70, 71- 80 and >80. A cross-sectional analysis of OKS at different time points was performed.

The numbers of OKS available for analysis were 504 pre-operatively, 589 at one-year, 512 at two-year and gradually decreasing numbers with 87 knees ten-year post-operatively. There was as expected a significant decrease (improvement) of the OKS between pre-operative and one-year post-operative period and then reached a plateau. Beyond eight years, there is a gradual rise in the score (deterioration). The younger patients (60) showed a significant increase in their average OKS between one and five-years post-operatively. However beyond five years, they followed the trend of their older counterparts. When the twelve questions in the OKS were analysed, certain components revealed greater improvement (e.g. description of knee pain and limping) than others (e.g. night pain).

The OKS is seen to plateau a year after TKR. According to the OKS the outcome of the TKR is not as good in the younger age group as compared to the older age group. Further investigation is required to ascertain the cause of this observed difference.

Navigation in total knee replacement is now used more frequently. The proven benefits in comparison to a conventional knee replacement include reduced hospital stay, reduced blood loss, and improved component alignment. A retrospective study was carried out to evaluate the difference in post-operative pain outcomes between conventional and computer-assisted navigation knee arthroplasty in a high volume setting. Computer-assisted surgery may be more painful because of the extra pin holes required for the navigation. The amount of anti-emetic use between the two groups was also looked at as evidence exists that greater anti-emetic is used if pain levels are greater.

All the navigated arthroplasty operations were performed by one of two surgeons in a single hospital using a uniform surgical approach and navigation system. A single type of prosthesis was used in the conventional group. In the first part of the study, the navigated group consisted of 87 patients and the conventional group of 40 patients (total = 127 cases). In the second ‘antiemetic use’ study, the navigated group consisted of 71 patients and the conventional group of 39 (total = 110). The analgesic and anti-emetic use was collated for the 72-hour post-operative period. This was chosen so that any analgesic influence of the anesthetic would have been negated over this period.

Pain scores were measured over the 72 hour period at regular intervals using a visual analogue scale. Patients in the navigated group seemed to report less pain in the first 24 hours but this was later reversed. Interestingly, their pain scores were more constant during this period, whilst the conventional group exhibited greater variability. The actual difference in pain scores between the two groups was however not significant (p=0.33).

The amount of opioid used by patients in each group was the primary factor used to see if a difference exists between the two procedures. The assumption was made that a correlation exists between opioid usage and pain. The total opioid usage was calculated by using referenced opioid conversion calculations for intravenous and oral forms of morphine including weaker opioids such as codeine and tramadol.

The average opioid used in the conventional group was 164.8 mg whilst in the navigated it was 173.7mg. However using the Student’s t-test this difference was not significant with a p value = 0.69. The percentage of patients requiring opioid greater than 300mg in 72 hours was actually greater in the conventional group (15% vs 12.6%).

The average antiemetic use looking initially at cyclizine was 57.7mg in conventional and 50.4mg in the navigated. This difference was also not significant (p=0.59).

On analysis of the tourniquet times between the groups it was noted that the average time for a conventional operation was 89.6 minutes whilst it was 88.6 minutes in the other. This is in contrast to previous findings and it seems that the learning curve is improving at least in this high volume setting.

This paper suggests that there is no difference between the two groups with respect to pain experienced in the post-operative period.

Paradoxical cerebral embolism is seen in 50–60% of patients following hip and knee arthroplasty surgery. It is responsible for post-operative symptoms like confusion and cerebral ischemic episodes. Embolism is less common with the use of uncemented implants. No study has looked into incidence of cerebral emboli in hip resurfacing.

We undertook a prospective randomised study to look at the incidence of cranial emboli in hip resurfacing. Patients were randomized to receive either uncemented or cemented femoral component. An arm of the study included evaluation of the effects of femoral venting by randomising patients to ‘venting’ or ‘no venting’ of proximal femur intra-operatively. The operations were performed by a single surgeon using a uniform surgical technique. Transcranial Doppler device was used to quantify the occurrence and distribution of cerebral microemboli. Emboli counts were recorded continuously and were correlated any major procedural event.

Eight patients (5 vented, 3 unvented) underwent cemented resurfacing and 7 patients (4 vented, 3 unvented) had cementless resurfacing. There was no difference between the two groups for age, gender, weight, or ASA status. Peri-operatively both groups were similar for vital observations (heart rate, temperature, blood pressure), haemoglobin change, mini – mental score at day 1 and 2, and oxygen saturation at day 1 and 3.

The mean number of significant emboli in the cemented group was 8.1 and in the cementless group was 1.7 (significant, p=0.009). Venting did not influence rate of emboli however, venting was independently associated with significantly higher drainage (mean 604mls compared to 335mls without venting, p=0.018). There was no significant difference in post-operative haemoglobin or number of units transfused.

Cranial emboli occur commonly after hip resurfacing. Their incidence is significantly reduced by the use of uncemented femoral component, however venting of proximal femur doesnot appear to make any difference.

An intra-operative splash is a common occurrence in elective knee and hip replacement surgery and can potentially transmit bloodborne diseases, with devastating consequences. This study aimed to quantify the risk of a splash and to assess its correlation with body mass index, duration of surgery and the volume of lavage fluid used.

Between December 2007 and April 2008, 62 consecutive patients (38 women, 24 men) undergoing an elective total knee or total hip replacement (TKR, THR) were recruited into the study (32 TKRs and 30 THRs) after appropriate consent.

A splash occurred in all 62 cases. A THR had a slightly higher risk of a splash than a TKR, but this was not statistically significant (p = 0.27). The correlation between body mass index, duration of surgery and the amount of pulse lavage used with a splash was r = 0.013, (non-significant), r = 0.52, (significant) and r = 0.92 (highly significant), respectively.

A high number of splashes are generated during a TKR and a THR. The simple visor mask fails to protect the surgeon, the assistant or the patient from the risk of a splash and reverse splash, respectively.

INTRODUCTION: The American Knee Society score (AKSS) and the Oxford Knee score (OKS) are widely used health outcome measures for total knee replacements. The AKSS is a surgeon-assessed, variable weighted knee score. The OKS is a patient assessed equally weighted score. Our aim was to evaluate whether patient self assessment is a viable alternative to clinical review and whether it can provide enough information to identify which patient would require a clinic visit.

As there had been no previous studies correlating the two scoring systems, we investigated whether a correlation exists between the two scores at 2, 5 and 10 year periods. A correlation would allow us to determine what OKS value would achieve 90% sensitivity in identifying patients requiring clinical review at the above time points. This strategy would reduce the number of clinical visits required and its associated cost.

METHODS: We reviewed the data gathered prospectively from January 2000 to April 2006. All patients were part of an ongoing multi-surgeon single institution Knee Arthroplasty Outcome Programme. Preoperative, 2, 5 and 10 year post-operative OKS and AKSS were gathered from different cohorts. This method of comparison has been validated by previous publications. The scores were then analyzed using the Pearson correlation and linear regression. Different OKS values were analyzed for sensitivity and specificity.

RESULTS: 175 patients completed both the OKS and AKSS questionnaires preoperatively. 312 completed both scores at 2 years; 124 at 5 years and 57 patients at 10 years. The mean OKS, and the two AKSS components, the Knee score and Functional score improved significantly 2 years postoperatively when compared to their preoperative values. The Functional score deteriorated significantly from 5 to 10 years (p< 0.0001). There was good correlation between the OKS and the Knee score and Functional score at 2 years and a moderate correlation at 5 to 10 years. OKS > 24 showed more than 90 % sensitivity in identifying poor Knee scores in the 2, 5 and 10 year periods.

CONCLUSION: In this study, the good correlation of OKS and AKSS at 2-years suggests that postal Oxford questionnaire is sufficient in following up patients in the short term after total knee replacement. However, the moderate correlation at 5 and 10 years suggests that clinical evaluation is necessary.

We recommend that at 2 years, all patients complete an OKS questionnaire and if this is above 24, a clinical evaluation maybe required. Using this OKS value as a screening technique would allow a reduction of up to 50% in clinic visits and outpatient costs at the 2 year follow-up. This reduction is not as great at the 5 and 10 year periods. At these time periods, we recommend a clinical follow-up.

We report the clinical and radiological outcome at ten years of 104 primary total hip replacements (100 patients) using the Metasul metal-on-metal bearing. Of these, 52 had a cemented Stuehmer-Weber polyethylene acetabular component with a Metasul bearing and 52 had an uncemented Allofit acetabular component with a Metasul liner. A total of 15 patients (16 hips) died before their follow-up at ten years and three were lost to follow-up. The study group therefore comprised 82 patients (85 hips).

The mean Oxford score at ten years was 20.7 (12 to 42). Six of 85 hips required revision surgery. One was performed because of infection, one for aseptic loosening of the acetabular component and four because of unexplained pain. Histological examination showed an aseptic lymphocytic vasculitis associated lesion-type tissue response in two of these. Continued follow-up is advocated in order to monitor the long-term performance of the Metasul bearing and tissue responses to metal debris.

Introduction: A cementless femoral implant is currently available for hip resurfacing with several theoretical advantages over cemented fixation, one of which is a potential reduction in systemic emboli. A prospective study was undertaken to evaluate the occurrence of systemic emboli using a cementless femoral component for hip resurfacing in comparison to cemented femoral fixation.

Methods: Between November 2004 and December 2005 patients scheduled for elective hip resurfacing for osteoarthritis were consented to undergo hip resurfacing using a cemented femoral component (Articular Surface Replacement or Birmingham Hip Resurfacing) or a cementless femoral component (Bi-coat Cormet Hip Resurfacing). Each case was randomised to femoral venting or no femoral venting. Intra-operative monitoring with a Transcranial Doppler device was used to identify and record systemic emboli throughout each case. Demographic and peri-operative data were collected including mental score and vital observations at day 1 and day 3, and blood loss.

Results: 8 patients (5 vented, 3 unvented) underwent cemented resurfacing and 7 patients (4 vented, 3 unvented) had cementless resurfacing. There was no difference between the two groups for age (mean 56yrs), gender, weight, or ASA status. The mean number of significant emboli (> 12dB) in the cemented group was 8.1 and in the cementless group was 1.7 (significant, p=0.009). Peri-operatively both groups were similar for vital observations, haemoglobin, mental scores and SaO₂. Venting did not influence rate of emboli. However, venting was independently associated with significantly higher drainage (mean 604mls compared to 335mls without venting, p=0.018).

Discussion: This study has shown significantly less systemic emboli occur with the use of a cementless femoral component during hip resurfacing in comparison to a cemented implant. We propose this is due to intra-osseus pressure generated when using cement. The number of emboli is unaffected by femoral venting, but more blood loss occurs after venting.

Computer navigation assistance in total knee arthroplasty (TKA) results in more consistently accurate postoperative alignment of the knee prostheses. However the medium and long term clinical outcomes of computer-navigated TKA are not widely published. Our aim was to compare patient perceived outcomes between computer navigation assisted and conventional TKA using the Oxford knee score (OKS).

We retrospectively collected data on 441 primary TKA carried out by a single surgeon in a dedicated arthroplasty centre over a period of four years. These were divided according to use of computer navigation (group A) or standard instrumentation (group B). There were no statistical differences in baseline Oxford knee score (OKS) and demographic data between the groups. 238 of these had at least a one-year follow-up with 109 in group A and 129 in group B. Two year follow-up data was available for 105 knees with 48 in group A and 57 in group B and a three year follow-up for 45 with 21 and 24 in groups A and B respectively. 12 patients had completed four year follow-up with seven and five knees in groups A and B respectively.

The mean OKS at 1-year follow up was 24.98 (range 12– 54, SD 9.34) for group A and 26.54 (range 12– 51, SD 10.18) for group B (p = 0.25). Similarly at 2-years the mean OKS was 25.40 (range 12– 53, SD 9.51) for group A and 25.56 (range 12– 46, SD 9.67) for group B (p = 0.94). The results were similar for three and four-year follow ups with p values not significant. This study thus revealed that computer assisted TKA does not appear to result in better patient satisfaction when compared to standard instrumentation at midterm follow up.

It is known from long term analysis of conventional TKA that mal-aligned implants have significantly higher failure rates beyond eight to ten years. As use of computer navigation assistance results in a less number of mal-aligned knee prostheses, we believe that these knees will have improved survivorship. The differences in OKS between the two groups should therefore be evident after eight to ten years.

Obesity [Body Mass Index (BMI) > 30kg/m2] is seen in a growing percentage of patients seeking joint replacement surgery. Operations in obese patients take longer and present certain technical difficulties. Computer navigation improves consistency of prosthetic component alignment but increases operation time.

Our aims were

to compare tourniquet times of non-obese with obese patients having knee replacement using standard instruments or computer navigation and

A retrospective analysis of 232 total knee replacement (TKR) operations performed by a single knee surgeon over a three year period was carried out. Similar knee prostheses (Plus Orthopedics, UK) were used in all cases. Variables to be assessed were the operative technique (computer navigation assisted or standard instruments) and BMI of patients.

Of the 232 knees, 117 were performed using computer navigation and 115 with standard instruments. Each of the groups was subdivided as per BMI to differentiate obese patients (BMI > 30) from the non-obese. Tourniquet times of surgery were used for comparison amongst the subgroups.

There were 56 and 59 patients in the non-obese and obese subgroups respectively within the standard TKR group. The average tourniquet times for these were 79.3 and 86.3 minutes respectively. This was a significant difference (p=0.037). Correspondingly in the computer navigated group, there were 60 non-obese and 57 obese patients. Their tourniquet times were 105.4 and 100.5 minutes respectively. This difference was not significant (p=0.15)

The obese patients in each group were then studied separately and divided into three equally sized subgroups in chronological order. Each sub-group comprised 19 standard TKRs and 19 computer navigated TKRs. Tourniquet times of operations were compared within each sub-group. P values within the first subgroup showed a significant difference. There was no significant difference within the second and third subgroups.

We concluded that obesity significantly increased the operative time in the standard TKR group. However in computer navigated TKR there was no significant difference in operative time between non-obese and obese patients. As the surgeon acquired experience of computer navigation there was no difference in time taken for conventional and computer navigated TKR in obese patients. We hypothesize that in obese patients, computer assisted navigation helps the surgeon to overcome jig alignment uncertainty without any time penalty.

Introduction: Obesity [Body Mass Index (BMI) > 30] is seen in a growing percentage of patients seeking joint replacement surgery. Recent studies have shown no clear influence of obesity on the five-year, clinical outcome of total knee replacement; except for the morbidly obese (BMI > 40). Computer navigation has shown improved consistency of prosthetic component alignment. However, this aid does significantly increase operation time.

Aims:

To compare tourniquet times of standard and computer assisted total knee arthroplasty in patients with BMI more than 30

Methods and Results: A retrospective analysis of 82, obese, total knee replacements performed by a single surgeon, at a dedicated arthroplasty centre, was undertaken. Conventional knee replacement instrumentation (Plus Orthopaedics, UK) was used in 42 cases and computer assisted navigation (Galileo- Plus Orthopaedics) in 39 cases. The patients were divided into three equal sized groups (1, 2 & 3), in chronological order. Each group comprised fourteen knees undertaken using standard surgical technique and thirteen knees using computer assisted navigation.

Group1 had average tourniquet times of 95.69 and 111.67 minutes in the standard and computer assisted groups respectively (p 0.01). Group 2 tourniquet times were 80.75 and 92.33 minutes (p 0.05). Group 3 tourniquet times were 84.5 and 87.5 minutes; these were not significantly different.

Conclusions: As the surgeon acquired experience of computer assisted navigation, his tourniquet times decreased and by the end of our study period, there was no longer any difference between the tourniquet times for conventional and computer assisted knee replacement in this subgroup of obese patients. We hypothesise that in obese patients, computer assisted navigation helps the surgeon to overcome jig alignment uncertainty and thus improves accuracy of component alignment without any significant time penalty.

We audited the relationship between obesity and the age at which hip and knee replacement was undertaken at our centre. The database was analysed for age, the Oxford hip or knee score and the body mass index (BMI) at the time of surgery. In total, 1369 patients were studied, 1025 treated by hip replacement and 344 by knee replacement. The patients were divided into five groups based on their BMI (normal, overweight, moderately obese, severely obese and morbidly obese).

The difference in the mean Oxford score at surgery was not statistically significant between the groups (p > 0.05). For those undergoing hip replacement, the mean age of the morbidly obese patients was ten years less than that of those with a normal BMI. For those treated by knee replacement, the difference was 13 years. The age at surgery fell significantly for those with a BMI > 35 kg/m² for both hip and knee replacement (p > 0.05). This association was stronger for patients treated by knee than by hip replacement.

We undertook a prospective, randomised study using a non-invasive transcranial Doppler device to evaluate cranial embolisation in computer-assisted navigated total knee arthroplasty (n = 14) and compared this with a standard conventional surgical technique using intramedullary alignment guides (n = 10). All patients were selected randomly without the knowledge of the patient, anaesthetists (before the onset of the procedure) and ward staff. The operations were performed by a single surgeon at one hospital using a uniform surgical approach, instrumentation, technique and release sequence. The only variable in the two groups of patients was the use of single tracker pins of the imageless navigation system in the tibia and femur of the navigated group and intramedullary femoral and tibial alignment jigs in the non-navigated group.

Acetabular Doppler signals were obtained in 14 patients in the computer-assisted group and nine (90%) in the conventional group, in whom high-intensity signals were detected in seven computer-assisted patients (50%) and in all of the non-navigated patients.

In the computer-assisted group no patient had more than two detectable emboli, with a mean of 0.64 (SD 0.74). In the non-navigated group the number of emboli ranged from one to 43 and six patients had more than two detectable emboli, with a mean of 10.7 (sd 13.5). The difference between the two groups was highly significant using the Wilcoxon non-parametric test (p = 0.0003).

Our findings show that computer-assisted total knee arthroplasty, when compared with conventional jig-based surgery, significantly reduces systemic emboli as detected by transcranial Doppler ultrasonography.

Twenty patients underwent simultaneous bilateral medial unicompartmental knee arthroplasty. Pre-operative hip-knee-ankle alignment and valgus stress radiographs were used to plan the desired post-operative alignment of the limb in accordance with established principles for unicompartmental arthroplasty. In each patient the planned alignment was the same for both knees. Overall, the mean planned post-operative alignment was to 2.3° of varus (0° to 5°).

The side and starting order of surgery were randomised, using conventional instrumentation for one knee and computer-assisted surgery for the opposite side.

The mean variation between the pre-operative plan and the achieved correction in the navigated and the non-navigated limb was 0.9° (sd 1.1; 0° to 4°) and 2.8° (sd 1.4; 1° to 7°), respectively. Using the Wilcoxon signed rank test, we found the difference in variation statistically significant (p < 0.001).

Assessment of lower limb alignment in the non-navigated group revealed that 12 (60%) were within ± 2° of the pre-operative plan, compared to 17 (87%) of the navigated cases.

Computer-assisted surgery significantly improves the post-operative alignment of medial unicompartmental knee arthroplasty compared to conventional techniques in patients undergoing bilateral simultaneous arthroplasty. Improved alignment after arthroplasty is associated with better function and increased longevity.

We carried out a prospective randomised study to evaluate the blood loss in 60 patients having a total knee arthroplasty and divided randomly into two equal groups, one having a computer-assisted procedure and the other a standard operation. The surgery was carried out by a single surgeon at one institution using a uniform approach. The only variable in the groups was the use of intramedullary femoral and tibial alignment jigs in the standard group and single tracker pins of the imageless navigation system in the tibia and femur in the navigated group.

The mean drainage of blood was 1351 ml (715 to 2890; 95% confidence interval (CI) 1183 to 1518) in the computer-aided group and 1747 ml (1100 to 3030; CI 1581 to 1912) in the conventional group. This difference was statistically significant (p = 0.001). The mean calculated loss of haemoglobin was 36 g/dl in the navigated group versus 53 g/dl in the conventional group; this was significant at p < 0.00001.

There was a highly significant reduction in blood drainage and the calculated Hb loss between the computer-assisted and the conventional techniques. This allows the ordering of less blood before the operation, reduces risks at transfusion and gives financial saving. Computer-assisted surgery may also be useful for patients in whom blood products are not acceptable.