One of the main surgical goals when performing a total knee replacement (TKR) is to ensure the implants are properly aligned and correctly sized; however, understanding the effect of alignment and rotation on the biomechanics of the knee during functional activities is limited. Cardiff University has unique access to a group of local patients who have relatively high frequency of poor alignment, and early failure. This provides a rare insight into how malalignment of TKR's can affect patients from a clinical and biomechanical point of view to determine how to best align a TKR. This study aims to explore relationship clinical surgical measurements of Implant alignment with in-vivo joint kinematics. 28 patient volunteers (with 32 Kinemax (Stryker) TKR's were recruited. Patients undertook single plane video fluoroscopy of the knee during a step-up and step-down task to determine TKR in-vivo kinematics and centre of rotation (COR). Joint Track image registration software (University of Florida, USA) was used to match CAD models of the implant to the x-ray images. Hip-Knee-Ankle (HKA) was measured using long-leg radiographs to determine frontal plane alignment. Posterior tibial slope angle was calculated using radiographs. An independent sample t-test was used to explore differences between neutral (HKA:-2° to 2°), varus (≥2°) and valgus alignment (≤-2°) groups. Other measures were explored across the whole cohort using Pearson's correlations (SPSS V23). There was found to be no statistical difference between groups or correlations for HKA. The exploratory analysis found that tibial slope correlated with Superior/Inferior translation ROM during step up (r=−0.601, p<0.001) and step down (r=−.512, p=0.03) the position of the COR heading towards the lateral (r=−.479, p=0.006) during step down. Initial results suggest no relationship between frontal plane alignment and in-vivo. Exploratory analyses have found other relationships that are worthy of further research and may be important in optimizing function.
The TruFit® plug is a cylindrical scaffold designed to bridge defects in articular cartilages. It is a porous structure with interconnected pores, which gives it the capability of providing a framework for the ingrowth new tissue and remodelling to articular cartilage and bone. The aim of this study was to assess the radiological incorporation of TruFit® Plugs using MRI. Between December 2007 & August 2009, 22 patients underwent treatment of a chondral or osteochondral lesion using one or more TruFit Plugs. At a minimum of 2 years, 10 patients (12 lesions) were MRI scanned and assessed with a modified MOCART Scoring system by an independent Consultant Musculoskeletal Radiologist. 8 patients were no longer contactable and 4 patients declined MRI as their knee was asymptomatic. 8 of 12 lesions showed congruent articular cartilage cover with a surface of a similar thickness and signal to the surrounding cartilage and reconstitution of the subchondral bone plate. 2 lesions had a thicker congruent articular surface with a similar signal to the surrounding articular cartilage without restoration of the subchondral bone plate. 2 lesions showed no graft incorporation at all and were filled with granulation tissue. Full incorporation of the bony portion of the plug had occurred in only 3 lesions with partial incorporation in 7 lesions. The remaining portion of these 7 lesions looked cystic on MRI. The MRI appearances of the TruFit® Plug at 2 years are encouraging with the majority (83%) showing good restoration of the articular surface with tissue of similar thickness, congruity and signal as the surrounding articular cartilage. However complete incorporation of the TruFit® Plug is rare and cystic change is common. The significance of this cystic change is not clear.
Patellofemoral replacement is an established intervention in selected patients with severe isolated patellofemoral osteoarthritis. FPV (Wright Medical, UK) is a third generation patellofemoral arthroplasty implant and is the second most used after AVON in National Joint Registry for England and Wales. Reports of survivorship and functional of this implant are scarce in literature. Evaluation of functional outcome and survivorship following FPV patellofemoral arthroplasty.Background
Aim
To review the Five year survivorship of Kinnemax TKA performed at the NHS Treatment Cantre, Weston-Super-Mare (WSM), and compare it to a similar cohort from our institution. As part of the government's initiative to reduce waiting times for major joint surgery in Wales, the Cardiff and Vale NHS Trust (CAVOC) sent 224 patients (258 knees) to the NHS Treatment Centre in Weston-Super-Mare (WSM) for total knee arthroplasty. Controversy remains as to the unexpectedly high revision rates previously seen.Purpose
Introduction
For 42 of the 54 (78%) subjects, during isometric and walking exercises we observed that activation of the VMO, rectus femoris (RF) and vastus lateralis (VL) muscles of the symptomatic leg was not significantly different from those of the asymptomatic leg (p<
0.01). However, for 31 patients (57%) during the eccentric phase of the squat exercises, the symptomatic leg presented with high activation of VL compared to VMO and RF (p<
0.01). During the concentric phase, 45 patients (83%) presented with higher activation of the VL compared to the VMO.
358 patients, 190 SB and 168 DB were considered for statistical analysis from these five papers. Outcome measures assessed included pivot shift testing, KT1000 arthrometer testing and IKDC knee scores. Using Review Manager 4.2 for statistical analysis; for dichotomous data, odds ratios and 95% confidence intervals were calculated and for continuous data, weighted mean difference and 95% confidence intervals were calculated. Patients in the double bundle group were significantly less likely to have a positive pivot shift test (P<
0.0001). KT1000 arthrometer testing demonstrated greater antero-posterior stability with the DB group (P=0.002). There was no difference between the groups in terms of IKDC score.
Following introduction of the second offer scheme in April 2004, Cardiff and Vale NHS Trust sent 227 patients (254 knees) to the independent sector treatment centre in Weston-Super-Mare for total knee arthroplasty. The Kinemax total knee system was used in all cases. There was a perception that there were a large number of dissatisfied patients, and a previous British Orthopaedic Association report (of a 14 case sample) questioned the quality of the surgery performed. All of the patients concerned were offered a review in order to assess the outcome. Of the 227 patients (254 knees), 77% have been reviewed (167 patients, 190 knees). 23% (59 patients, 64 Knees) have not been seen. Of these, 30 patients (34 knees) declined review on the basis that they were happy with the result of surgery. 14 Patients (15 knees) were unobtainable by post of by phone. A further 12 patients (12 knees) did not attend appointments. 3 Patients (3 Knees) had died. The total number of re-operations was 27/254, giving a re-operation rate of 10.6%. There were 21 revisions, 17 for aseptic causes (oversized components, malalignment, aseptic loosening) and 4 for infection. There were 6 secondary patella resurfacings. A life table survivorship analysis was calculated for the 254 knees. The cumulative survival rate at 3 years was 85.8%. These results are considerably worse than those reported in the current published literature. This has resulted in a significant economic impact on our service.
Between 29th May 2001 and 15th May 2003, 233 consecutive Preservation unicompartmental knee replacements (UKR) were performed. Of these, 30 were lateral UKRs (13%) performed in 12 men and 16 women (2 bilateral cases) with a mean age of 67 years (range 36 to 93 years). A metal-backed mobile bearing tibial component was used in 13 knees and an all-polyethylene fixed bearing tibial component in 17 knees. The patients were reviewed prospectively at 1 and 2 years. The 2 year results show no difference in range of motion or function between the mobile and fixed bearing versions of the Preservation knee when used on the lateral side. This is similar to the reported results on the medial side. There were 3 early revisions, all in the mobile bearing group. The incidence of revision has been reduced by the introduction of an improved cementing technique.
The aim of this study was to assess the results of bilateral total knee replacement (TKR) staged one week apart during one hospital admission and compare these results with those of bilateral sequential TKRs and bilateral TKRs performed in 2 separate admissions by a single surgeon using a single prosthesis. Between 5th November 1997 and 10th August 2004, 104 patients underwent bilateral LCS TKRs using the Anteroposterior glide (APG) tibial component. The patients were analysed in 3 groups. The patients in Group 1 underwent bilateral sequential TKR under the same anaesthetic. The patients in Group 2 underwent bilateral TKRs under 2 separate anaesthetics, 7 days apart, during the same admission. The patients in Group 3 underwent bilateral TKR under 2 separate admissions, essentially 2 unilateral TKRs. The patients in Group 1 had shorter operations (p<
0.0001) and shorter hospital stays (p<
0.0001). Patients in Group 2 had less blood loss (p=0.004) but were not transfused any less than the other groups. The complication rate was low and comparable in all groups. There were no in hospital or 30 day deaths in any of the groups. Those patients in Group 3 had worse AKS function scores (p=0.02) and those patients in Group 2 had a significantly better HSS score (p=0.02). There was no significant difference between the groups in terms of range of motion or the AKS Knee score. This study has confirmed a shorter operation and hospital stay when the bilateral TKRs are carried out under the same anaesthetic. These patients also bled the most postoperatively. There was little difference in terms of complications and clinical outcome at a mean follow up of 4 years. With appropriate patient selection, both same anaesthetic and same admission bilateral TKR are safe methods to treat bilateral arthritis.
The aim of this study was to assess the perioperative complications associated with bilateral simultaneous UKR and compare them with those of unilateral UKR and bilateral TKRs. Over a 2 year period, 40 patients underwent bilateral simultaneous Preservation unicompartmental knee replacement UKR. They were compared to 40 matched unilateral UKRs and 28 bilateral simultaneous total knee replacement patients who had their operations during the same time period by the senior author. There was no significant difference between the groups in terms of age, weight, ASA grade and throm-boprophylaxis received. There was no statistically significant difference in the complication rates of all 3 groups. When compared to 2 unilateral UKRs, bilateral simultaneous UKR results in a reduced operative time, blood loss and hospital stay but more blood transfusion. When compared to bilateral TKRs, bilateral simultaneous UKR results in reduced blood loss, reduced blood transfusion and hospital stay but an increased operative time. Bilateral UKR is a useful option in selected patients with bilateral unicompartmental osteoarthritis.
The aim of this prospective cohort study is to compare the early results in a single surgeon series of the mobile and fixed bearing versions of the Preservation UKR for lateral OA. Lateral UKRs were only considered for patients with isolated lateral compartment osteoarthritis with a functioning anterior cruciate ligament. Mild patellofemoral osteoarthritis was not considered a contraindication. If there was any doubt over the condition of the medial compartment or patellofemoral joint, single photon emission computed tomography was performed. Significant uptake it the medial or patellofemoral joint was considered a contraindication. Patients were assessed preoperatively and at 1 and 2 years postoperatively with the American Knee Society Score (AKSS), Oxford Knee Score (OKS) and with anteroposterior, lateral and Rosenberg radiographs. Between 29th May 2001 and 15th May 2003, the senior author (GK) performed 233 consecutive Preservation UKRs. Of these, 30 were lateral UKRs (13%) performed in 12 men and 16 women (2 bilateral cases) with a mean age of 67 years (range 36 to 93 years). A metal-backed mobile bearing tibial component was used in 13 knees and an all-polyethylene fixed bearing tibial component in 17 knees. Patients in the mobile bearing group were significantly younger (t test; p<
0.0001) and had better AKSS knee (Mann-Whitney U test; p=0.05) and AKSS function scores (Mann-Whitney U test; p=0.005). The patients were reviewed after a minimum of 2 years (range 2 to 3.4 years). There was no significant difference between the 2 groups. There had been 3 revisions in the mobile bearing group for tibial loosening and none in the fixed bearing group (chi squared test; not significant). There was 1 tibial periprosthetic fracture in the fixed bearing group. This study shows that the choice of bearing type makes little difference in clinical outcome or range of motion over the first 2 years when using the Preservation Knee. A similar good functional result was obtained with a fixed bearing despite the mobile bearing group being younger and having significantly better preoperative AKS knee and function scores. The 3 revisions for tibial loosening in the mobile bearing group are a concern. However, these results are short-term and there may be improved implant longevity in the long-term with mobile bearing tibial components due to reduced polyethylene wear.
To assess the reliability of the pre-operative measurement methods used in the management of the hallux valgus deformity, five observers assessed 50 pre-operative standing foot radiographs on two occasions in order to assess the reliability of radiological hallux valgus assessment using the inter-metatarsal angle (IMA), hallux valgus angle (HVA) and joint congruency. Five published methods of angle measurements described by Hawkins, Venning and Hardy, Mitchell, Miller and Nestor were used. Kappa statistics were used to assess the reliability of the diagnosis of congruency. Regarding IMA and HVA, mean values between the methods were assessed by one-way ANOVA. The differences between the methods and observers were assessed by two-way ANOVA.
The mean IMA and HVA measurements varied significantly between methods on both occasions (p<
0.0001). Mitchell’s method had the lowest and Miller’s the highest mean values. Analysis of variance showed both method and observer variations were significant for IMA. But HVA measurements differed significantly only by observers.
The aetiology of Panner’s disease is unknown. Thrombophilic states have been implicated in Perthes’ disease but remain controversial. The relationship, if any, between thrombophilia and Panner’s disease is not known. A 7 year old boy presented with pain and restriction of motion in one elbow with no history of trauma. Radiographs confirmed Panner’s disease. A thrombophilia screen showed an abnormal activated protein C resistance test consistent with the presence of Factor V Leiden in the heterozygous state. Thrombophilia may predispose to thrombotic venous occlusion in bone leading to intramedullary hypertension, anoxia and avascular necrosis. This may explain the aetiology of some cases of Panner’s disease. Resistance to activated protein C is a common heritable thrombophilia. The incidence in the UK is around 1.75%. It is caused by a CGA to CAA substitution at position 1691 of the Factor V Leiden gene. This blocks the binding of activated protein C to prothrombotic Factor V producing thrombophilia. Factor V Leiden carriers are three times more likely to experience clinical venous thrombosis than non-carriers. Whilst this risk does not warrant lifelong anticoagulation, thromboembolic events are more likely to cause problems than Panner’s disease which is essentially self-limiting. Affected patients should avoid other risk factors such as smoking or the combined contraceptive pill. As Factor V Leiden is common in our population, its presence in this patient may be incidental. Thrombophilia screening should be considered for patients with Panner’s disease. This enables appropriate counselling if a thrombophilic condition is found.
A systematic review was performed to determine the advantages and disadvantages of patellar resurfacing during total knee replacement for osteoarthritis. 3 randomised controlled studies were analysed. These studies recruited 302 knees and 235 knees (78%) were reviewed at least 5 years postoperatively (range 5 to 10 years). Patients undergoing patellar resurfacing received a cemented all polyethylene patella component. A patello-plasty was performed in some of the unresurfaced knees. For the dichotomous data, odds ratios and 95% confidence intervals were calculated. Each outcome measure tested was assessed for heterogeneity using the Cochran Q test. If significant heterogeneity was present (P<
0.10), data from the studies was not combined. If there was no significant heterogeneity, a combined odds ratio was calculated using a fixed effects model and a Z test was performed to test the overall effect. Reoperation for patellofemoral problems was significantly more likely in the unresurfaced group (p=0.003). The overall rate for reoperation for a patellofemoral problem was 0.7% in the resurfaced group and 11% in the unresurfaced group. Study data on anterior knee pain could not be analysed together as there was significant heterogeneity. There was no difference between the two groups in terms of revision. This study found no mid- to long-term benefit to leaving the patella unresurfaced.
The choice of graft for anterior cruciate ligament reconstruction remains controversial. A systematic review was performed to compare bone-patella tendon-bone and 4-strand hamstring grafts. Medline (1966 onwards), EMBASE (1980 onwards) and the Cochrane database were searched retrieving 6312 possible articles but only 6 studies fulfilled all the inclusion criteria. To be included, the study had to be prospective, randomised or quasi-randomised, comparing 4SHS and central third BPTB autografts, inserted using an arthroscopically assisted technique and have a minimum 2-year follow up for all patients. These studies recruited 526 patients and 475 were followed for at least 2 years with 235 patients receiving a bone-patella tendon-bone graft and 240 receiving a 4-strand hamstring graft. Overall, there was a greater chance of extension loss (p=0.007) and a trend towards increased patellofemoral joint pain (p=0.09) with a patella tendon graft. With a 4-strand hamstring graft there is a greater loss of hamstring power (p=0.008) and a trend towards an increased chance of a pivot shift >
1 (p=0.12). There was no difference between the 2 groups in terms of lachman testing, chance of returning to the same level of sport, clinical knee scores, graft ruptures or other complications.
A systematic review was performed to determine the advantages and disadvantages of patellar resurfacing during total knee replacement for osteoarthritis. 3 randomised controlled studies were analysed. These studies recruited 302 knees and 277 knees (92%) were reviewed at least 5 years postoperatively (range 5 to 10 years). Patients undergoing patellar resurfacing received a cemented all polyethylene patella component. A patelloplasty was performed in some of the unresurfaced knees. Each outcome measure tested was assessed for heterogeneity using the Cochran Q test. If significant heterogeneity was present (P<
0.10), data from the studies was not combined and the studies were examined for possible explanations. If there was no significant heterogeneity, a combined odds ratio was calculated using a fixed effects model and a Z test was performed to test the overall effect. Reoperation for patellofemoral problems was significantly more likely in the unresurfaced group (p=0.003). The overall rate for reoperation for a patellofemoral problem was 0.7% in the resurfaced group and 12% in the unresurfaced group. Study data on clinical knee scores and anterior knee pain could not be analysed together as there was significant heterogeneity. There was no difference between the two groups in terms of revision. This study found no mid- to long-term benefit to leaving the patella unresurfaced.
The choice of graft for anterior cruciate ligament reconstruction remains controversial. A systematic review was performed to compare bone-patella tendon-bone and 4-strand hamstring grafts. Medline (1966 onwards), EMBASE (1980 onwards) and the Cochrane database were searched retrieving 6312 possible articles but only 6 studies fulfilled all the inclusion criteria. To be included, the study had to be prospective, randomised or quasirandomised, comparing 4SHS and central third BPTB autografts, inserted using an arthroscopically assisted technique and have a minimum 2-year follow up for all patients. These studies recruited 526 patients and 475 were followed for at least 2 years with 235 patients receiving a bone-patella tendon-bone graft and 240 receiving a 4-strand hamstring graft. Overall, there was a greater chance of extension loss (p=0.007) and a trend towards increased patellofemoral joint pain (p=0.09) with a patella tendon graft. With a 4-strand hamstring graft there is a greater loss of hamstring power (p=0.008) and a trend towards an increased chance of a pivot shift >
1 (p=0.12). There was no difference between the 2 groups in terms of lachman testing, chance of returning to the same level of sport, clinical knee scores, graft ruptures or other complications.
The five different methods of measuring hallux valgus (HVA) and intermetatarsal angles (IMA) and the diagnosis of congruency of first MTP joint were studied on 50 pre-operative standing foot radiographs, to test if these methods were reliable and the results reproducible enough to be used in a treatment algorithm for hallux valgus. Analysis of variance (ANOVA) was used to examine the difference between the five methods and between the five observers. Kappa test was used to measure agreement in diagnosing congruency between two occasions. The mean IMA and HVA varied significantly (p<
0.00001). The ANOVA model showed that method and observer variations were both significant for IMA; there was no significant difference between measurement methods for HVA. Congruency had good (k=0.608) intraobserver and fair (k=0.261) interobserver reliability. A second IMA measurement will lie between 4.2° less and 4.6° more than the first IMA measurement 95% of the time. A second HVA measurement will lie between 6° less and 5.6° more than the first HVA measurement 95% of the time. Overall, there was no advantage to any of the measurement methods, although some observers were better than others. All methods had considerable inter- and intra-observer variability that makes these measurements unreliable.
39 consecutive patients (40 hips) undergoing femoral impaction grafting were retrospectively reviewed to assess our mid-term results and analyse them for any factors that could influence outcome. 36 revisions were for aseptic loosening, 3 for infection and 1 following a periprosthetic fracture. Those hips revised for infection were revised in 2 stages. In 37 cases, the Exeter X-Change bone impaction technique was used, implanting an Exeter stem with Simplex cement through a posterior approach. A Charnley stem was implanted in the 3 others. Each surviving patient was assessed using the Harris hip score, AP pelvis and lateral hip radiographs. Potential prognostic factors were analysed using the Spearman’s rank correlation test. The patients were reviewed after a mean follow-up of 5 years. 1 patient didn’t wish to attend review but was asymptomatic. Complications included 4 intraoperative femoral fractures during cement removal, 2 postoperative femoral fractures, 2 dislocations, 1 femoral component fracture and 1 deep infection. There were 3 re-revisions and 1 Girdlestones procedure. The median Harris hip score of those implants still in-situ was 78.5. Those patients who had previously undergone a revision had a significantly worse Harris hip score (p<
0.05). The patients age, reason for revision, preoperative bone loss, surgeon, simultaneous acetabular revision, simultaneous bone grafting to acetabulum, loose acetabular component on radiographs, femoral subsidence, presence of trabeculae in the graft, any radiolucency, a complete cement mantle and ectopic bone formation had no significant correlation to the Harris hip score. In this series, previous revision was found to be the only significant risk factor for a poor Harris hip score after femoral impaction grafting. Postoperative radiographic changes in this group correlated poorly with function and could not predict outcome. Further study is required to assess other factors such as bone graft and soft tissue quality that may also predict outcome.