Arthrofibrosis following total knee replacement; does therapeutic warfarin make a difference?

Arthrofibrosis following total knee replacement (TKR) is a relatively common complication which results in a reduction in knee range of movement and patient dissatisfaction. A retrospective study examined the relationship between anticoagulation with therapeutic warfarin and rates of arthrofibrosis following TKR. Arthrofibrosis was defined as less than 80 degrees of knee flexion 6-8 weeks post-TKR. Patients were warfarinised if they had a history of thrombophilic tendencies or medical conditions necessitating anti-coagulation, rather than as routine thromboprophylaxis. All other patients received thromboprophylaxis using low molecular weight heparin. A total of 728 patients underwent 874 primary TKR between 1993 and 2002 in one centre, performed by four surgeons. Mean age was 68 years (range 48-89 years) and there were 483 female and 391 male knees. Eighty cases were warfarinised post-operatively (53 female, 27 male). Overall, 83 of 874 TKRs (9%) had arthrofibrosis (57 female, 26 male) requiring manipulation under anaesthetic (MUA). In the warfarinised group, 21 knees (26%) had an MUA (15 female, 6 male). This compared to 62 cases (8%) requiring MUA in the non-warfarinised group (42 female, 20 male). There was a statistically significant difference on Fisher's exact testing (P<0.0001) between groups. Following MUA, knee flexion improved in 95% cases to a minimum 95 degrees but 8 cases had a fixed flexion deformity of 5-10 degrees . In conclusion, therapeutic warfarinisation post-TKR leads to a statistically greater chance of the patient developing arthrofibrosis compared to prophylactic low molecular weight heparin and that patients should be counseled appropriately.     

Is routine splintage following primary total knee replacement necessary? A prospective randomised trial

It was hypothesised that routine splintage following primary total knee replacement has no affect on flexion deformity and offers no benefit over simple wool and crepe. Fifty-five patients undergoing primary total knee replacement were entered into a prospective study. The patients were randomly assigned to two groups: The first group was rehabilitated without a splint and the second received an adjustable semi-rigid extension splint (Richards splint) for the first 48 h after surgery. Range of motion measurements were recorded pre-operatively and at 2 days, 1 week and 3 months post-operation by a research nurse blinded to the allocation. No statistically significant difference in flexion deformity was found at any stage (P>0.5). No difference was found in general or wound complications, or requirement for blood transfusion, and the post-operative stay was equal in the two groups. We conclude that routine use of a semi-rigid splint following primary total knee replacement has no advantage over simple wound dressings.     

Epidural collection following a late infected total knee replacement — A case report

Prosthetic joint infection is a well-described complication following primary joint replacement. The association between an epidural abscess and joint replacement surgery following the use of epidural anaesthetics has been previously documented. There is however, no report in the literature of an epidural abscess forming as a result of haematogenous spread from an infected prosthetic joint. This case report presents such a scenario and highlights the importance of early diagnosis and treatment of infected prosthetic joints to avoid further systemic complications.     

Should the patella be resurfaced at total knee replacement?

Total knee replacement (TKR) presumably is replacement of the total knee articular surface. Sometimes it is and sometimes it is not. It is this author's firm conviction that the patella should be resurfaced in the vast majority of cases. Such advocacy must be critically justified and the potential drawbacks and alternatives examined.     

Should the patella be resurfaced during total knee replacement?

Patellar resurfacing during total knee replacement (TKR) has been a controversial subject for many years. In 1990 a randomised prospective study was started to compare policies of resurfacing, not resurfacing and selectively resurfacing the patella. One hundred and twenty-five cases (suitable for a cruciate sparing TKR) were randomised. At the 5-year review, the group in which the patella had not been resurfaced had needed significantly more secondary surgery than the other groups. Global knee scoring systems showed little difference between the groups but a scoring system which focused on the patella revealed differences and demonstrated worse results when the patella was not resurfaced. A minor degree, of maltracking was tolerated in resurfaced knees but tended to cause pain and articular cartilage wear in unresurfaced patellae. Four knees with good patellar articular cartilage at surgery did poorly when not resurfaced, suggesting that a selective policy is not totally reliable. Routine patellar resurfacing gave the most reliable results.     

Revision of medial Oxford unicompartmental knee replacement to a total knee replacement: Similar to a primary?

Unicompartmental knee replacement (UKR) is an option for the treatment of isolated medial compartment osteoarthritis. A commonly perceived potential advantage is that revision of a UKR is straightforward. The purpose of this study was to determine the early outcomes and the level of complexity of revisions of Oxford UKRs performed at our hospital. A retrospective review of a prospective database of all phase III Oxford UKRs was undertaken. This identified 89 Oxford UKRs which were revised at our institution between 2002 and 2008. The median time from the primary procedure to revision was 19 months (interquartile range 2-73 months). Nine were revised to another UKR. Eighty were revised to a total knee replacement (TKR). Fifty-three were revised with primary TKR components. Twenty-seven were revised using stems and/or augments. The median overall tibial component thickness (including augments) was 15 mm. Forty-five knees had an overall tibial component thickness greater than 15 mm. A primary Oxford UKR bearing thickness of greater than 6mm was associated with an increased likelihood of requiring revision components. On the basis of this review, tibial bone defects were commonly encountered when revising UKRs. Reconstruction with either an augment and a stem, or thick polyethylene component was often required. We recommend that the potential complexity of revision for UKR failure should be borne in mind when considering a primary Oxford UKR.     

How useful is templating for total knee replacement component sizing?

This study aims to assess the accuracy of digital templating at our institution, by comparing the templated component sizes with those implanted, and to determine whether templating the preoperative films had any measurable difference on the radiographic outcome, and if, where there was a mismatch between the implanted and templated sizes, the templated size would have been preferable. While a number of studies have evaluated the accuracy of both acetate and digital templating, none has to our knowledge looked back at post-operative radiographs and reviewed these in light of the templated and implanted sizes. Data was collected from 90 PFC Sigma (DePuy, UK) total knee replacements done sequentially, 45 of whom were templated digitally using a calibrating ball and Agfa Orthopaedic Tools software. Postoperative radiographs were graded independently for correct sizing. All templates were within one size of the implanted prosthesis. The femoral component appeared to be more often oversized on the postoperative radiographs in the non-templated group. In addition, most tibial trays that were found be too small had been templated to a larger size. There was a trend towards tibial trays templated too large to have been templated to a smaller size. We conclude that digital templating with a calibrating device is a useful part of preoperative planning for total knee arthroplasty.     

Does preoperative anxiety and depression predict satisfaction after total knee replacement?

Background and purposeApproximately one fifth of patients are not satisfied with the outcome of total knee arthroplasty (TKA). Preoperative variables associated with poorer outcomes are severity and chronicity of pain, psychological disease, poor coping strategies and pain catastrophisation. Psychological disease may be expressed as anxiety and depression. It is unclear whether anxiety and depression before TKA are constitutional or result from knee pain. The aim of this study was to explore the association of anxiety and depression with knee pain and function using specific outcome measures.MethodsForty consecutive patients undergoing TKA completed Hospital Anxiety and Depression Scale (HAD) and Oxford Knee Scores (OKS) preoperatively and at 3 and 6 months postoperatively.ResultsThe HAD and OKS significantly improved post-operatively (p < 0.001). There was a greater change between the preoperative and postoperative scores in the OKS than the HAD. The severity of preoperative anxiety and depression was associated with higher levels of knee disability (coefficient ? 0.409, p = 0.009). Postoperatively reduction in anxiety and depression was associated with improvement in knee disability after 3 (coefficient ? 0.459, p = 0.003) and 6 months (coefficient ? 0.428, p = 0.006).InterpretationThe difficulty in interpreting preoperative anxiety and depression and the outcome of TKA is establishing whether they are the cause or effect of pain in the knee. As anxiety and depression improve with knee pain and function, this study suggests that knee pain contributes to the psychological symptoms and that a successful TKA offers an excellent chance of improving both.     

The St. Leger total knee replacement. A false economy?

We reviewed the outcome of 53 primary St. Leger total knee replacement (TKR) implanted into 47 patients over a 2-year period from March 1995 and compared the outcome with age and sex matched controls with the Kinemax Plus TKR. All operations were performed to treat osteoarthritis of the knee. The St. Leger replacements were done in a Teaching Hospital by a Consultant surgeon while the Kinemax Plus replacements were done in the same hospital by two other surgical teams. During the period of review, 13 patients (13 knees) with St. Legers died or were too demented to participate, and 4 were lost to follow up. Eleven patients (13 knees) with the Kinemax died or were too demented to cooperate, and 2 patients (2 knees) were lost to follow up. The St. Leger group had inferior Oxford Knee Scores to the Kinemax group but this was not significant. The St. Leger group had significantly worse survivorship of the prosthesis. The St. Leger prosthesis was cheaper (Pound sterling 650) than the Kinemax (Pound sterling 1150). The initial saving was dwarfed by the ultimate cost of revision procedures.     

Tibial component overhang following unicompartmental knee replacement—Does it matter?

As implants are made in incremental sizes and usually do not fit perfectly, surgeons have to decide if it is preferable to over or undersize the components. This is particularly important for unicompartmental knee replacement (UKR) tibial components, as overhang may cause irritation of soft tissues and pain, whereas underhang may cause loosening.One hundred and sixty Oxford UKRs were categorised according to whether they had minor (< 3 mm, 70%) or major (≥ 3 mm, 9%) tibial overhang, or tibial underhang (21%). One year post surgery, there was no significant difference in outcome between the groups. Five years after surgery, those with major overhang had significantly worse Oxford Knee Scores (OKS) (p = 0.001) and pain scores (p = 0.001) than the others. The difference in scores was substantial (OKS = 10 points). There was no difference between the ‘minor overhang’ and the ‘underhang’ group.We conclude that surgeons must avoid tibial component overhang of 3 mm or more, as this severely compromises the outcome. Although this study showed no difference between minor overhang or underhang, we would advise against significant underhang because of the theoretical risk of component subsidence and loosening.     

Has modern human immunodeficiency virus therapy decreased complications following total knee arthroplasty?

BackgroundAnti-retroviral therapy (ART) remains the cornerstone of decreasing morbidity and mortality in human immunodeficiency virus (HIV) patients. However, a large study comparing HIV patients taking ART prior to total knee arthroplasty (TKA) is lacking. We sought to examine: (1) readmissions; (2) post-operative complications; and (3) revisions in ART-treated or untreated HIV patients compared with a non-HIV population.MethodsWe queried a national, all-payer database to identify TKA patients from 2010-2020 (n = 1,393,357). The presence or absence of ART was identified and matched with non-HIV patients based on age, sex, diabetes, obesity, and tobacco status resulting in 889 patients in each cohort. Readmissions, post-operative complications, and revisions were assessed.ResultsReadmissions were higher among all HIV patients and even higher in those not taking ART, as compared to the matching cohort (4.8 versus 1.6%, p < 0.01). Prosthetic joint infections (PJIs) at 1-year were higher among HIV patients who were either taking ART (4.0%; OR, 1.41 [0.82–2.45]) or not taking ART (5.1%; OR, 2.44 [1.42–4.21]) as compared to non-HIV patients (2.1%, all p < 0.03). Revision rates at 1-year trended higher in HIV patients who were taking ART (2.6%; Odds Ratio (OR), 1.94 [0.96–3.93]) and who did not take ART (3.1%; OR, 2.38 [1.20–4.70]), compared to non-HIV patients (1.3%, all p < 0.09).ConclusionsART-treated HIV patients are associated with lower readmissions, post-operative complications, and revisions when compared to HIV patients not taking ART. The findings of this study underscore the utility of ART and patient optimization to reduce risk in HIV patients.     

Unexplained pain following total knee arthroplasty: Is rotational malalignment the problem?

Background

Malrotation of tibial and femoral components is a potential source of pain following total knee arthroplasty (TKA). This study aimed to 1) compare component rotation in TKA patients with unexplained pain versus a control group with well-functioning TKAs and 2) investigate the relationship between TKA component rotation and pain.

Can the epicondylar axis be defined accurately in total knee arthroplasty?

As part of a study on rotational alignment of the femoral component in knee replacement, the surgical epicondylar axis was identified in 74 knees and marked with pins. An alternative technique was employed to achieve rotational alignment and in each case the distance between the pins and the cut surface of the posterior condyles was measured. The alignment of the femoral component was measured postoperatively by axial CT scans of the distal femur, allowing an assessment to be made of what would have been achieved if the epicondylar pins had been used for guidance. Only 75% of knees would have been within 3 degrees of the true epicondylar axis using the epicondyles to control rotation. The error range was large (range 6 degrees ER to 11 degrees IR). Our conclusion is that even in experienced hands clinical estimation of the epicondylar axis is inaccurate and should not be relied upon as the sole determinant of femoral rotation.     

Can tibio-femoral kinematic and kinetic parameters reveal poor functionality and underlying deficits after total knee replacement? A systematic review

BackgroundExtensive efforts have been made to understand joint kinematics and kinetics in total knee arthroplasty (TKA) in subjects with satisfactory outcomes during daily functional activities and clinical tests, but it remains unclear whether such movement characteristics hold the potential to indicate the underlying aetiology of unsatisfactory or bad TKA outcomes.PurposeTo investigate which kinematic and kinetic parameters assessed during passive clinical tests and functional activities of daily living are associated with poor functionality and underlying deficits after total knee replacement.MethodsWe focused on studies characterizing the kinematic or kinetic parameters of the knee joint that are associated with poor clinical outcome after TKA. Seventeen articles were included for the review, and kinematic and kinetic data from 719 patients with minimal follow up of 6 months were extracted and analyzed.ResultsPassive posterior translation at 90° flexion exhibited good potential for differentiating stable and unstable TKAs. Anterior-posterior (A-P) translation of the medial condyle at 0–30° and 30–60° flexion, A-P translation of the lateral condyle at 60–90° during closed chain exercises, as well as knee extension moment during stair ascent and descent, knee abduction moment during stair descent, knee internal rotation moment and plantar flexion moment during walking, 2nd peak ground reaction force during stair ascent and walking showed the greatest promise as functional biomarkers for a dissatisfied/poor outcome knee after TKA.ConclusionIn this study, we systematically reviewed the state-of-the-art knowledge of kinematics and kinetics associated with functional deficits, and found 11 biomechanical parameters that showed promise for supporting decision making in TKA.     

Fatal pulmonary embolism following elective total knee replacement using aspirin in multi-modal prophylaxis — A 12 year study

Background

The National Institute for Health and Clinical Excellence (NICE) has issued guidelines on which thromboprophylaxis regimens are suitable following lower limb arthroplasty. Aspirin is not a recommended agent despite being accepted in orthopaedic guidelines elsewhere. We assessed the incidence of fatal pulmonary embolism (PE) and all-cause mortality following elective primary total knee replacement (TKR) with a standardised multi-modal prophylaxis regime in a large teaching district general hospital.

How to quantify knee function after total knee arthroplasty?

Total knee arthroplasty (TKA) is being undertaken in a younger population than before and as a result the functional demands on the knee are likely to be increasing. As a consequence, it is important to define quantitative functional knee tests that can monitor any increase.A valuable functional knee test has to be able to distinguish small differences (selectivity) and has to be independent of pain (content validity). In this study, patient-based questionnaires (WOMAC and Knee Society score) and performance-based tests (sit-to-stand movement, maximal isometric contraction and timed-up-and-go) were used to assess which of these tests are selective and valid to measure knee function. Tests were considered to be selective if they could discriminate between knee patients and healthy control subjects, and to have functional content validity if they were relatively independent of pain. Twenty-eight patients were measured 16 months after surgery and compared to a healthy control group of 31 subjects.The sit-to-stand movement and timed-up-and-go test were both selective and functionally content valid. The timed-up-and-go test can be used for a quick initial assessment of global function and the sit-to-stand movement as a more biomechanical instrument identifying how the knee function of the patient is affected.     

Is a tourniquet beneficial in total knee replacement surgery?: A meta-analysis and systematic review

Proponents of tourniquets postulate that they optimise intra-operative visibility and reduce blood loss. This study compared the outcomes of tourniquet assisted to non-tourniquet assisted total knee replacement (TKR). A systematic review was undertaken of the electronic databases Medline, CINAHL, AMED and EMBASE, in addition to a review of unpublished material and a hand search of pertinent orthopaedic journals. The evidence-base was critically appraised using a tool from the Cochrane Bone, Joint and Muscle Trauma Group. Fifteen studies were identified evaluating 16 outcome measures and parameters of 1040 TKRs in 991 patients. There was a significantly greater intra-operative blood loss in non-tourniquet compared to tourniquet assisted surgery (p = 0.004). There was no significant difference between the groups for total blood loss or transfusion rate (p = 0.22; p = 0.48). There was a trend for greater complications in tourniquet compared to non-tourniquet patients. There was no difference between the groups for any other outcome measure assessed. In conclusion, this systematic review has found that there is no advantage to using a tourniquet in knee replacement surgery for reduction of transfusion requirements.     

Can knees kneel? Kneeling ability after total,unicompartmental and patellofemoral knee arthroplasty

This study investigates patients' perception of kneeling ability before and at 1 and 2 years after total, unicompartmental knee replacement (UKR) and patellofemoral knee replacement (PFR), for osteoarthritis. Kneeling is an important function of the knee joint required for many daily activities and inability to kneel after knee surgery is a frequent cause of dissatisfaction. Data were prospectively collected on 253 knees. A kneeling score was obtained by analysis of the relevant section of the Oxford knee score. Scores were obtained pre-operatively and at 1 and 2 years post-operatively. Absolute values and change following surgery were recorded. Correlations with pain and other knee functions were also made. Kneeling ability prior to surgery was poor in all 3 groups (80% found it extremely difficult or impossible to kneel) and improved in all groups after surgery (20% had little or no difficulty to kneel at 2 years). Kneeling ability was best in UKR and worst in PFR. These results suggest that kneeling ability in osteoarthritic patients is poor but improves with knee arthroplasty surgery, however the majority of patients will still have difficulty in kneeling.