Knee

Is manipulation under anaesthesia really a solution?

A significant number of patients find rehabilitation following total knee arthroplasty (TKA) challenging, with an appreciable proportion of patients developing some stiffness leading to a poor range of movement. We know that a loss of 90° of flexion and fixed flexion deformities lead to poor outcomes and functional impairment associated with significant dissatisfaction. The aetiology of such a complication is multifactorial, including poor preoperative range of movement, large body habitus, previous knee trauma, and non-compliance with postoperative rehabilitation regimens. But for all of this, even in the best hands with the best postoperative regimes, some patients just get stiff. Intraoperative surgical errors should not, of course, be overlooked, including inadequate bone resection, failure to balance the flexion and extension gaps, and component malrotation. However, even when a surgically satisfactory TKA has been performed, persistent stiffness may still develop secondary to arthrofibrosis. Despite intensive physiotherapy and continuous passive motion (CPM) devices, some patients still require manipulation under anaesthesia (MUA) to break down some of the fibrous adhesions formed within the knee that limit range of movement. There have been a number of studies published on MUA for stiffness post-TKA but there appears to be little consensus on patient demographics that predict success and when the MUA should be performed. The authors of this study reviewed all of the relevant literature to date in order to arrive at a conclusion to help guide the management of patients with a stiff TKA. This review team from New York, New York (USA) undertook a review of 22 papers reporting the outcomes of 1488 patients in an attempt to identify the expected outcomes and predictors (if any) of success.¹ In this series, the mean time between TKA and MUA was 9.9 weeks (2 to 22) and there was a significant improvement in flexion, on average, following MUA in all studies. There was an overall complication rate of less than 1% associated with MUA. Complications included supracondylar fractures, haemarthrosis, wound dehiscence, and deep vein thrombosis. Four studies reported on the outcomes of repeat MUAs, with the majority reporting an improvement in the range of movement but an increased risk of complication. The authors concluded that the current literature supports intensive physical therapy, and CPM with MUA reserved for those patients who fail to improve with more conservative measures. With similar failure rates for MUA reported at different times from the index operation, the authors suggested that it is safe to allow a longer trial of conservative management for patients who are keen to avoid a MUA. However, this also assumes that there is easy access to 'aggressive' physiotherapy, which is not always the case in the outpatient setting. This may lead to patients being admitted for an earlier intervention due to the lack of outpatient physiotherapy services. The authors did add that, although there was no clear benefit to performing a MUA within 30 days of TKA, there is an added benefit when it is done within the first 12 weeks. On the whole, patients find TKA much more painful than total hip arthroplasty (THA), which directly affects their compliance with postoperative rehabilitation. More studies are needed to understand better the causes of this increased pain and how best to address it. This would hopefully see a reduction in those patients needing a MUA post-TKA.

Exercise in patients living with knee osteoarthritis

Knee osteoarthritis (OA) is common and is responsible not only for pain, but also for functional impairment. Essential activities of daily living become increasingly difficult with progressive arthritis, such as walking, squatting, and tackling stairs. Nonoperative measures have a significant and, in these days of austerity, an increasing role in the management of knee OA. The mainstay of conservative treatment is physical activity, modification of daily activities, weight loss, and analgesia. However, the authors of this study highlight that ineffective exercise can exacerbate the patient’s symptoms, resulting in the early abandonment of physical activity and increasing dependence on pharmacological agents to address symptoms. The authors from Winnipeg (Canada) describe a new treadmill that utilizes a technology called lower body positive pressure (LBPP).² They sought to examine the effect of a 12-week, LBPP-supported, low-load walking exercise regimen on knee pain, joint function, thigh strength, and ability to perform normal activities of daily living in patients with knee OA. The authors studied 31 overweight patients (mean body mass index (BMI) 32.8 kg/m²) aged between 50 and 75 years with symptomatic mild-moderate OA. Each participant completed a 12-week, LBPP-supported treadmill walking regimen that included exercising twice a week for 30 minutes at a speed of 3.1 mph. The LBPP support was then added in 5% increments each minute. Patients then underwent a post-exercise test in the week immediately following each walking exercise regimen. The authors noted a significant increase in quadriceps strength and a significant decrease in visual analogue scale (VAS) scoring of acute knee pain. There was also an improvement in knee outcome scores following completion of the 12-week walking regimen and a corresponding improvement in activities of daily living. It is common in the orthopaedic outpatient department that patients feel unable to do much in the way of exercise as it exacerbates their pain. Therefore, this study is to be commended for suggesting methods for patients with knee pain to undertake an exercise regimen that aims to reduce their discomfort without resorting to pharmacological measures. However, not all centres will have access to a LBPP treadmill, and one of the chief benefits to the healthcare system funder is that exercise advice is usually very low-cost. As the population ages and knee arthritis becomes more common, more high-quality research such as this is needed to review the effectiveness of nonoperative measures in order to win the confidence of both patients and surgeons alike.

The accuracy of alpha-defensin testing

Tranexamic acid superior to tourniquet

We were delighted, here at 360, to see this randomized controlled trial (RCT) from Sichuan (China) that investigates the use of tourniquet and tranexamic acid (TXA) in total knee arthroplasty (TKA).⁴ The authors reason that tourniquet use has found a place historically in TKA to reduce the intraoperative blood loss. However, the management of blood loss during TKA has undergone a significant change over the past few years, with TXA now considered the norm in many centres for large joint arthroplasty. Perhaps in the light of the TXA revolution, it is time to re-evaluate tourniquet use? The authors report their RCT, which was designed to test the use of both TXA and tourniquet, in isolation and in combination, on blood loss during TKA. They recruited 150 patients to their study and randomized them into three groups, one with a tourniquet and intravenous TXA, one with the tourniquet alone, and one with TXA alone. The authors report that a similar level of intraoperative blood loss was seen in all three groups; however, there was a significant difference seen in postoperative blood loss. There was a difference favouring the TXA-alone group in terms of ‘hidden’ blood loss. When looking at other outcomes such as total blood loss, drain volumes, and haemoglobin (Hb) changes, there were no differences between the two groups that received TXA, and both performed better than the tourniquet-alone group. In terms of postoperative evaluations, there were differences in postoperative swelling ratio, levels of inflammatory biomarkers, visual analogue scale (VAS) pain scores, range of motion at discharge, Hospital for Special Surgery (HSS) score, and patient satisfaction favouring the TXA-alone group. Prior to this study, it was customary to use a tourniquet with TXA, the idea being that the combination would provide better results. However, this study demonstrates that multiple doses of intravenous TXA, along with topical TXA, provide better results than when using TXA and tourniquets in combination. Perhaps the era of using tourniquets during TKA is coming to a close!

Meniscal allograft transplantation: a pilot randomized controlled trial

There are some treatments that, on the face of it, are very attractive, but, when the details are worked out, have never been widely adopted. This may be due to costs, complications, or lack of hard data. Meniscal transplantation is one of those procedures. We know that absence of a functional meniscus hastens the onset of knee arthritis and we also know that it is possible to transplant a meniscus; however, the technique – probably for logistical and technical reasons – is still a rarely used treatment. Due to the rarity of its application, there is little conclusive literature as to whether meniscal transplantation is a viable solution for all but the most specialized of surgeons in the most select of patients. We were delighted to read this pilot randomized controlled trial (RCT) from Coventry (UK) that aims to evaluate the potential for meniscal transplantation in a small cohort of patients, all with a symptomatic meniscal deficient knee compartment.⁵ The authors sought to compare the meniscal transplantation with personalized physiotherapy at 12 months of follow-up. Outcomes were assessed primarily using patient-reported outcome measures (PROMs): the Knee injury and Osteoarthritis Outcome Score (KOOS), International Knee Documentation Committee (IKDC) score, and Lysholm scale. These were administered at baseline, four, eight, and 12 months to both groups. In addition, complications and adverse events were collected and reported. The treatment allocations were something of a mixed bag, with 36 patients entering the study; just 21 were randomly allocated and the remainder chose their treatments. The authors, however, argue that as the outcomes were similar in the randomized and preference groups, the data could be pooled for final analysis. Within the constraints of a pilot study, this is more reasonable than in a fully powered trial, when considering that pilot studies are primarily for effect size calculations, although, with nearly half of the patients wishing to choose their treatment, this does have impact on the feasibility of a larger study. Ultimately, at 12 months, the KOOS composite score and KOOS subscales of pain and activities of daily living were significantly better in the meniscal transplantation group. We should consider these results very carefully. Although meniscal transplantation has been eyed with suspicion in parts of the orthopaedic community, this pilot trial would suggest that in the right patients it likely has an application. Clearly, a larger trial is needed, and one with longer follow-up. In order to reach the threshold for the incremental cost-effectiveness ratio (ICER) and funding in the National Health Service (NHS), this would need to be a long-lasting and relatively effective treatment. Here at 360 we are watching this space.

Medial pivot versus condylar knee designs

Implant design may not be the major factor in outcomes following knee arthroplasty; however, there are some fundamentally different approaches to implant design and postoperative alignment. The discussion surrounding kinematic and traditional alignment, unicompartmental versus total knee, and posterior-stabilized versus not, has been, and continues to be, explored and debated, with research studies conducted often to support the point of view of the originating unit. One such debate that has never been quite as well-explored in the literature is that of the medial pivot knee, which promised more accurate matching of the normal knee biomechanics, perhaps with a more favourable polyethylene wear profile due to decoupling of rotational and linear motion. Researchers from London (UK) have reported a subgroup analysis of patients who were recruited to a prospective randomized controlled trial that compared medial pivot and condylar resurfacing designs.⁶ The outcomes of the main trial are not presented here but the authors do report an interesting subgroup analysis of patients’ biomechanical characteristics having undergone either an anatomical single radius design or a medial pivot design. Outcome measurements included clinical scores (Knee Society Score (KSS) and Oxford Knee Score (OKS)); however, the most interesting outcome reported was the gait analysis using an instrumented treadmill. The bottom line with this study was that the authors were unable to report any real differences between the two groups. With no statistically significant difference for either clinical score (KSS and OKS) or in a broad range of gait analysis factors (cadence, walking speed, stride length and stance time, peak stride, mid-support, and push-off forces), we are led to the conclusion by the authors that, despite the dramatically different design features of these two devices, the biomechanical design in this paper does not seem to have much of a role to play in either.

Thirty-day mortality after weekend versus weekday arthroplasty

There has been much interest in the weekend effect and the potential for excess mortality. The authors of this study from Bristol (UK) look at the outcomes of elective arthroplasty following weekend surgery, which has become a hot political topic with allegations of excess deaths being used as a political tool to argue for seven-day hospital services.⁷ The other side of the coin, usually argued by clinicians, is that the excess deaths at the weekend can be explained by patient differences rather than staffing level differences, and a combination of increased comorbidity and the excess of emergency work explains the variation seen in large observational studies. This very interesting study using National Joint Registry Data examines the potential weekend effect and its effect on mortality in patients who are admitted for an elective joint arthroplasty with 30-day mortality as the primary endpoint. As is commonplace with registry studies, the numbers examined here are eye-watering. Over the lifetime of the registry there were 118 096 episodes undertaken at the weekend, and 1 233 882 joint arthroplasties performed during the week. There is, nonetheless, a rather low event rate at 30-day mortality for hip arthroplasty, at 0.15% for weekend operation and 0.20% for weekday operating. The equivalent figures for the knee were 0.14% and 0.18%, respectively, again lower at the weekend. This does, however, only equate to just over 170 deaths over the entire period of the study at the weekend. It seems unlikely that there will be a better study that looks at planned elective surgery over a weekend, with sufficiently high numbers from which to establish mortality figures, but it does identify the problems, and this study probably goes as far as it is possible to go in order to show that weekend elective surgery is not more dangerous than weekday surgery.