The aim of our study was to determine the current incidence and outcome of infected total knee arthroplasty (TKA) in our unit comparing them with our earlier audit in 1986, which had revealed infection rates of 4.4% after 471 primary TKAs and 15% after 23 revision TKAs at a mean follow-up of 2.8 years. In the interim we introduced stringent antibiotic prophylaxis, and the routine use of occlusive clothing within vertical laminar flow theatres and 0.05% chlorhexidine lavage during arthroplasty surgery. We followed up 931 primary TKAs and 69 revision TKAs for a mean of 6.5 years (5 to 8). Patients were traced by postal questionnaire, telephone interview or examination of case notes of the deceased. Nine (1%) of the patients who underwent primary TKA, and four (5.8%) of those who underwent revision TKA developed deep infection. Two of nine patients (22.2%) who developed infection after primary TKA were successfully treated without further surgery. All four of the patients who had infection after revision TKA had a poor outcome with one amputation, one chronic discharging sinus and two arthrodeses. Patients who underwent an arthrodesis had comparable Oxford knee scores to those who underwent a two-stage revision. Although infection rates have declined with the introduction of prophylactic measures, and more patients are undergoing TKA, the outcome of infected TKA has improved very little

Objectives. The purpose of this study was to examine the effect of posterior cruciate ligament (PCL) retention, PCL recession, and PCL excision during cruciate-retaining total knee replacement. Methods. A total of 3018 anatomic graduated component total knee replacements were examined; 1846 of these retained the PCL, 455 PCLs were partially recessed, and in 717 the PCL was completely excised from the back of the tibia. Results. Clinical scores between PCL groups favored excision for flexion (p < 0.0001), and recession and retention for stairs (p < 0.0001). There was a mild difference in long-term all-cause aseptic survivorship between PCL-retained (96.4% at 15 years) combined with PCL-recessed groups (96.6% at 15 years) when compared with the PCL-excised group (95.0% at 15 years) (p = 0.0411, Wilcoxon; p = 0.0042, log-rank), as well as tibial or femoral loosening, which reported prosthesis survival of 97.8% at 15 years for PCL-retained knees, 98.2% for recessed knees, and 96.4% for excised knees (p = 0.0934, Wilcoxon; p = 0.0202, log-rank). Conclusions. Despite some trade-off in clinical performance, if the PCL is detached at the time of operation, conversion to a posterior-stabilised prosthesis may not be necessarily required as long as stability in the anteroposterior and coronal planes is achieved

Ulceration of the lower leg is considered to be a ‘hard’ clinical endpoint of venous thrombosis. Total knee replacement (TKR) is a significant risk factor for venous thrombosis of the leg and therefore potentially for ulceration. We sent a postal questionnaire to 244 patients at a minimum of five years after TKR enquiring about the development of ulceration since their TKR. The overall incidence of ulceration, both active and healed, was 8.67% which is similar to that in the age-matched general population (9.6% to 12.6%), as was the prevalence of active ulceration. We also identified no clear association between venographically-confirmed postoperative deep-venous thrombosis (DVT) and the incidence and prevalence of ulcers at five years. We suggest that after TKR DVT is not a significant risk factor for ulceration of the leg and that perioperative chemical thromboprophylaxis may not be justified on these grounds

Haemophilia is an x-linked inherited bleeding disorder which can cause severe arthropathy. We have reviewed the results of 70 primary total knee replacements (TKR) performed in 57 haemophilic patients between 1983 and 2007. The functional results were assessed using the Hospital for Special Surgery (HSS) knee scoring system and Kaplan-Meier survivorship analysis. Six patients died. HSS scores were available for 60 TKRs at a mean follow-up of 9.2 years (2 to 23); 57 (95%) had good or excellent results. Deep infection was recorded in one patient. Kaplan-Meier analysis using infection and aseptic loosening as endpoints showed the survival rate at 20 years to be 94.0%. A reduction in infection, spontaneous haemarthrosis and improvement in the quality of life were noted to justify surgery in our series of patients with a mean age of 43 (25 to 70). We have found that using the latest techniques of continuous infusion of clotting Factor have significantly helped to reduce the complication rates and have achieved results which match those of the non-haemophilic population undergoing TKR

We have carried out a radiostereometric study of 50 patients (54 knees) with osteoarthritis of the knee who were randomly allocated to receive a cemented or a hydroxyapatite-coated femoral component for total knee replacement. The patients were also stratified to receive one of three types of articulating surface (standard, rotating platform, Freeman-Samuelson (FS)1000) all based on the Freeman-Samuelson design. The tibial components were cemented in all cases. Radiostereometry was performed post-operatively and at 3, 12 and 24 months. The analysis was restricted to rotation of the femoral component over time. After two years, rotation of the femoral components in the transverse, longitudinal and sagittal planes did not differ between the cemented and the hydroxyapatite-coated implants (p = 0.2 to 0.9). In total knee replacements with a rotating platform, the femoral component tended to tilt more posteriorly than in the other two designs, regardless of the choice of fixation (cemented or hydroxyapatite-coated, p = 0.04). The standard version of the femoral component, whether cemented or hydroxyapatite-coated, rotated more into valgus than was observed with the rotating-platform and FS1000 designs (p = 0.005). The increased constraint provided by the FS1000 component did not appear to have any adverse effect on fixation of the femoral component

We measured the driver reaction times of 40 patients before total knee replacement (TKR) and 4, 6, 8 and 10 weeks after operation. The ability to perform an emergency stop was assessed as the time taken to achieve a brake pressure of 100 N after a visual stimulus. There were 18 drivers and 11 non-drivers; the latter had longer reaction times. In drivers, the ability to transfer the right foot from accelerator to brake pedal did not recover to preoperative levels for eight weeks after right TKR and was unchanged after left TKR. Patients should be advised that they should not drive for at least eight weeks after right TKR

A soft-tissue defect over an infected total knee replacement (TKR) presents a difficult technical problem that can be treated with a gastrocnemius flap, which is rotated over the defect during the first-stage of a revision procedure. This facilitates wound healing and the safe introduction of a prosthesis at the second stage. We describe the outcome at a mean follow-up of 4.5 years (1 to 10) in 24 patients with an infected TKR who underwent this procedure. A total of 22 (92%) eventually obtained a satisfactory result. The mean Knee Society score improved from 53 pre-operatively to 103 at the latest follow-up (p < 0.001). The mean Western Ontario and McMaster Universities osteoarthritis index and Short-Form 12 score also improved significantly (p < 0.001). This form of treatment can be used reliably and safely to treat many of these complex cases where control of infection, retention of the components and acceptable functional recovery are the primary goals. Cite this article: Bone Joint J 2013;95-B:1217–21

The aim of this study was to determine the association between the Oxford knee score (OKS) and direct assessment of outcome, and to examine how this relationship varied at different time-points following total knee replacement (TKR). Prospective data consisting of the OKS, numerical rating scales for ‘worst pain’ and ‘perceived mean daily pain’, timed functional assessments (chair rising, stairs and walking ability), goniometry and lower limb power were recorded for 183 patients pre-operatively and at six, 26 and 52 weeks post-operatively. The OKS was influenced primarily by the patient’s level of pain rather than objective functional assessments. The relationship between report of outcome and direct assessment changed over time: R. 2. = 35% pre-operatively, 44% at six weeks, 57% at 26 weeks and 62% at 52 weeks. The relationship between assessment of performance and report of performance improved as the patient’s report of pain diminished, suggesting that patients’ reporting of functional outcome after TKR is influenced more by their pain level than their ability to accomplish tasks

This review summarises the opinions and conclusions reached from a symposium on infected total knee replacement (TKR) held at the British Association of Surgery of the Knee (BASK) annual meeting in 2011. The National Joint Registry for England and Wales reported 5082 revision TKRs in 2010, of which 1157 (23%) were caused by infection. The diagnosis of infection beyond the acute post-operative stage relies on the identification of the causative organism by aspiration and analysis of material obtained at arthroscopy. Ideal treatment then involves a two-stage surgical procedure with extensive debridement and washout, followed by antibiotics. An articulating or non-articulating drug-eluting cement spacer is used prior to implantation of the revision prosthesis, guided by the serum level of inflammatory markers. The use of a single-stage revision is gaining popularity and we would advocate its use in certain patients where the causative organism is known, no sinuses are present, the patient is not immunocompromised, and there is no radiological evidence of component loosening or osteitis. It is our opinion that single-stage revision produces high-quality reproducible results and will soon achieve the same widespread acceptance as it does in infected hip arthroplasty

We sought to determine the degree of correlation between the condition of the patellar articular cartilage and patellofemoral symptoms and function in osteoarthritic patients undergoing total knee arthroplasty. The depth of the osteoarthritic lesion, as graded by the Outerbridge classification and its size and location were assessed to determine the condition of the patellar cartilage in 80 consecutive osteoarthritic knees undergoing total knee arthroplasty. The association between the condition of the cartilage and patellofemoral symptoms and function was investigated by correlation analysis. The depth and size of the lesion had a significant but weak correlation with anterior knee pain (r = −0.300 and −0.289; p = 0.007 and 0.009, respectively), whereas location had no significant association (p > 0.05). None had a significant association with patellofemoral functional parameters (chair-rising, stair-climbing, and quadriceps power) (p > 0.05). Our study indicates that patellofemoral symptoms and function are not completely determined by the condition of the cartilage. Caution should be taken when the symptoms and functional limitations are attributed to a lesion in the patellofemoral joint in making a decision regarding patellar resurfacing in total knee arthroplasty

We carried out a prospective study of 118 hydroxyapatite-coated, cementless total knee replacements in patients who were ≤ 55 years of age and who had primary (92; 78%) or post-traumatic (26; 22%) osteoarthritis. The mean period of follow-up was 7.9 years (5 to 12.5). The Knee Society clinical scores improved from a pre-operative mean of 98 (0 to 137) to a mean of 185 (135 to 200) at five years, and 173 (137 to 200) at ten years. There were two revisions of the tibial component because of aseptic loosening, and one case of polyethylene wear requiring further surgery. There was no osteolysis or progressive radiological loosening of any other component. At 12 years, the overall rate of implant survival was 97.5% (excluding exchange of spacer) and 92.1% (including exchange of spacer). Cementless total knee replacement can achieve excellent long-term results in young, active patients with osteoarthritis. In contrast to total hip replacement, polyethylene wear, osteolysis and loosening of the prosthesis were not major problems for these patients, although it is possible that this observation could change with longer periods of follow-up

We have studied the concept of posterior condylar offset and the importance of its restoration on the maximum range of knee flexion after posterior-cruciate-ligament-retaining total knee replacement (TKR). We measured the difference in the posterior condylar offset before and one year after operation in 69 patients who had undergone a primary cruciate-sacrificing mobile bearing TKR by one surgeon using the same implant and a standardised operating technique. In all the patients true pre- and post-operative lateral radiographs had been taken. The mean pre- and post-operative posterior condylar offset was 25.9 mm (21 to 35) and 26.9 mm (21 to 34), respectively. The mean difference in posterior condylar offset was + 1 mm (−6 to +5). The mean pre-operative knee flexion was 111° (62° to 146°) and at one year postoperatively, it was 107° (51° to 137°). There was no statistical correlation between the change in knee flexion and the difference in the posterior condylar offset after TKR (Pearson correlation coefficient r = −0.06, p = 0.69)

The relationship between post-operative bone density and subsequent failure of total knee replacement (TKR) is not known. This retrospective study aimed to determine the relationship between bone density and failure, both overall and according to failure mechanism. All 54 aseptic failures occurring in 50 patients from 7760 consecutive primary cemented TKRs between 1983 and 2004 were matched with non-failing TKRs, and 47 failures in 44 patients involved tibial failures with the matching characteristics of age (65.1 for failed and 69.8 for non-failed), gender (70.2% female), diagnosis (93.6% OA), date of operation, bilaterality, pre-operative alignment (0.4 and 0.3 respectively), and body mass index (30.2 and 30.0 respectively). In each case, the density of bone beneath the tibial component was assessed at each follow-up interval using standardised, calibrated radiographs. Failing knees were compared with controls both overall and, as a subgroup analysis, by failure mechanism. Knees were compared with controls using univariable linear regression. Significant and continuous elevation in tibial density was found in knees that eventually failed by medial collapse (p < 0.001) and progressive radiolucency (p < 0.001) compared with controls, particularly in the medial region of the tibia. Knees failing due to ligamentous instability demonstrated an initial decline in density (p = 0.0152) followed by a non-decreasing density over time (p = 0.034 for equivalence). Non-failing knees reported a decline in density similar to that reported previously using dual-energy x-ray absorptiometry (DEXA). Differences between failing and non-failing knees were observable as early as two months following surgery. This tool may be used to identify patients at risk of failure following TKR, but more validation work is needed. Cite this article: Bone Joint J 2014;96-B:1503–9

The aim of this study was to find anatomical landmarks for rotational alignment of the tibial component in total knee replacement (TKR) in a CT-based study. Pre-operative CT scanning was performed on 94 South Korean patients (nine men, 85 women, 188 knees) with osteoarthritis of the knee joint prior to TKR. The tibial anteroposterior (AP) axis was defined as a line perpendicular to the femoral surgical transepicondylar axis and passing through the centre of the posterior cruciate ligament (PCL). The angles between the defined tibial AP axis and anatomical landmarks at various levels of the tibia were measured. The mean values of the angles between the defined tibial AP axis and the line connecting the anterior border of the proximal third of the tibia to the centre of the PCL was -0.2° (-17 to 14.1, . sd. 4.1). This was very close to the defined tibial axis, and remained so regardless of lower limb alignment and the degree of tibial bowing. Therefore, AP axis defined as described, is a reliable anatomical landmark for rotational alignment of tibial components. Cite this article: Bone Joint J 2014; 96-B:1485–90

The emergence of minimally-invasive total knee replacement (TKR) has led to the refinement of several surgical approaches, including the quadriceps-sparing and sub-vastus. There is some disagreement as to the precise definition of the term ‘minimally-invasive’, especially in regard to the preservation of vastus medialis obliquus (VMO). It is known that the termination of VMO is variable and may make these approaches difficult. We have attempted to assess the factors influencing the insertion of VMO and the impact which they have on the approach for TKR. The MR scans of 198 knees were examined to assess the variation in the insertion of VMO in relation to the patella and the effect of variables such as age, gender and the presence of concurrent osteoarthritis of the knee on the insertion. Our findings showed that both age and the presence of osteoarthritis were contributing factors to changes in the level of insertion of VMO. Therefore, not all capsular incisions which extend proximal to the midpole of the patella will violate the quadriceps tendon

We report the long-term survival of a prospective randomised consecutive series of 501 primary knee replacements using the press-fit condylar posterior cruciate ligament-retaining prosthesis. Patients received either cemented (219 patients, 277 implants) or cementless (177 patients, 224 implants) fixation. Altogether, 44 of 501 knees (8.8%) underwent revision surgery (24 cemented vs 20 cementless). For cemented knees the 15-year survival rate was 80.7% (95% confidence interval (CI) 71.5 to 87.4) and for cementless knees it was 75.3% (95% CI 63.5 to 84.3). There was no significant difference between the two groups (cemented vs cementless; hazard ratio (HR) 0.83, 95% CI 0.45 to 1.52, p = 0.55). When comparing the covariates there was no significant difference in the rates of survival between the side of operation (HR 0.58, p = 0.07), age (HR 0.97, p = 0.10) and diagnosis (HR 1.25 p = 0.72). However, there was a significant gender difference, with males having a higher failure rate with cemented fixation (HR 2.48, p = 0.004). Females had a similar failure rate in both groups. This single-surgeon series, with no loss to follow-up, provides reliable data of the revision rates of one of the most commonly-used total knee replacements. The survival of the press-fit condylar total knee replacement remained good at 15 years, irrespective of the method of fixation

The Morquio syndrome is a rare disorder which presents with a number of musculoskeletal problems. The literature describing total knee replacement in these patients is sparse. We describe the management of a patient with bilateral instability and pain in the knees using bilateral constrained knee replacements, and followed up for five years with pre- and postoperative knee scores. We highlight the difficulties encountered and discuss the end results

We describe the results of total knee arthroplasty (TKA) undertaken for severe, neurosyphilitic Charcot arthropathy in ten patients (19 knees). A cemented condylar, constrained prosthesis was implanted in all but two knees. The mean follow-up was 5.2 years (5 to 6). The mean knee score before operation was 36.5 points (30 to 42) which improved to 76 points (58 to 90) after operation as judged by the Hospital for Special Surgery score. At final follow-up three knees (16%) had aseptic loosening which required salvage by an arthrodesis, six (31%) were functioning poorly and ten (53%) were satisfactory. We conclude that although Charcot arthropathy is not an absolute contraindication to total knee replacement, there is a high incidence of serious complications

Compartment syndrome is a rare complication of total knee arthroplasty that requires early recognition and prompt decompression in order to prevent long-term disability. We have found only one previous case report in the literature. We present a series of seven cases from four hospitals and five surgeons. Six of the cases resulted in the loss of at least one compartment, and one resulted in amputation. Four of the cases resulted in legal action. We suggest that important risk factors contributing to the development of this condition include complex surgery, soft-tissue compromise, previous surgery, and possibly vascular disease. Delay in the diagnosis and hence delay in decompression was common in our series, and in five cases appeared to be related to the use of a postoperative epidural infusion for pain relief. The presence of associated neurological compromise may have also been a significant factor in the delay to diagnosis in two cases