99 knees were followed for 15 years and 21 knees for 20 years. The average Bristol knee score of the surviving knees fell from 86 to 79 during the second decade. A previous study showed an 89% 10 year survivor-ship and this is now extended to 82% at 15 years and 76.5% at 20 years.
The purpose of this study was to determine the incidence of revision total knee replacement (TKR) within 5 years of the index procedure at a large multi-surgeon unit using a single prosthesis and to determine the cause of failure of those implants. This was a retrospective review of all primary Kine-max Plus TKR performed at the Avon Orthopaedic Center between 1.1.1990 and 1.1.2000. Cases were identified that required revision arthroplasty in any form within 5 years of the index procedure. Case notes and Xrays were reviewed to determine causes of failure. There were 2826 primary Kinemax Plus TKR performed during the study period. Of these 20 were known to have required revision surgery within 5 years. 8 were revised for deep infection of the prosthesis and 12 for aseptic causes. The overall incidence of premature failure of the Kinemax Plus TKR at 5 years was 0.71%. The incidence of aseptic premature failure at 5 years was 0.42%. Detailed examination of the clinical records indicated that some form of technical error at the time of the index arthroplasty was responsible for the early failure of 6 prostheses. This equates to 0.21% of the procedures performed. Aseptic loosening of the remaining 6 cases could not be attributed to a specific cause.
To quantify the intraoperative cerebral microemboli load during primary total knee arthroplasty (TKA) using transcranial Doppler ultrasound and to investigate whether a patent foramen ovale influences cerebral embolic load in general. Patients undergoing primary TKA, with no history of stroke, TIA, ongoing CNS disease or alcoholism were included. All operations were carried out under a standardised general anaesthetic and performed by two consultant orthopaedic surgeons. Microemboli l oad was recorded, using transcranial Doppler ultrasound (TCD), onto VHS tape for subsequent playback and analysis. Patent foramen ovale detection was performed using bolus intravenous injection of agitated saline followed by valsalva manoeuvre technique and TCD. Timing of specific surgical steps was recorded for each operation and emboli load calculated for that period.
Medial unicompartmental replacement (UKR) has been shown to have superior functional results to total knee replacement (TKR) in appropriately selected patients, and this has been associated with a resurgence of interest in the procedure. This may relate to evidence showing that the kinematic profile of UKR is similar to the normal knee, in comparison to TKR, which has abnormal kinematics. Concerns remain over the survivorship of UKR and work has suggested the anterior cruciate ligament (ACL) may become dysfunctional over time. Cruciate mechanism dysfunction would produce poor kinematics and instability providing a potential mechanism of failure for the UKR.
A cross sectional study was designed in which 24 patients who had undergone successful UKR were recruited and divided into early (2–5 years) and late (>
9 years) groups according to time since surgery. Patients performed flexion/extension against gravity, and a step up. Video fluoroscopy of these activities was used to obtain the Patellar Tendon Angle (PTA), the angle between the long axis of the tibia and the patella tendon, as a function of knee flexion. This is a previously validated method of assessing sagittal plane kinematics of a knee joint. This work suggests the sagittal plane kinematics of a fixed bearing UKR is maintained in the long term. There is no evidence that the cruciate mechanism has failed at ten years. However, increased tibial bearing conformity from ‘dishing’, and adequate muscle control, cannot be ruled out as possible mechanisms for the satisfactory kinematics observed in the long term for this UKA.
70 patients who underwent dynamic MRI scanning for chronic anterior knee pain were retrospectively evaluated. All patients had been symptomatic for over a year. 43 patients had been treated conservatively and 27 had undergone surgical procedures (arthroscopy -13, lateral release- 9, tibial tubercle transfer 5). The extent of subluxation, tilt and cartilage abnormalities on MRI scans, during resisted extension were assessed. Functional scoring (Oxford, Lysholm and Tegner scores) was done through questionnaires and correlated with the radiological findings. 54 (77%) patients were found to have some patellofemoral abnormality on the scans. Subluxation was the most common finding with mild subluxation in 30, moderate in 18 and severe in 17 knees. Mild tilt was seen in 26 knees and moderate to severe tilt in 14 knees. Tilt was found in association with subluxation except in 8 cases. Grade 1 and 2 cartilage wear were seen in 13 knees and Grade 3 and 4 in 21 knees. The “Tibial Tubercle to Trochlear Groove distance” (TTD) was measured in all knees and correlated with subluxation. The average distance was 13.5mm, 13.6mm and 18.8mm for mild, moderate and severe subluxation respectively. All patients with a TTD _ 20mm had moderate or severe subluxation. The specificity of a TTD _ 20mm for severe maltracking was 100% but the sensitivity was only 42%. The TTD appears to be the single most significant parameter determining patella tracking. We have proposed an algorithm for the surgical and non-surgical treatment of chronic anterior knee pain. We recommend lateral release for those with moderate and severe subluxation and a tibial tubercle transfer as well in those with a TTD _ 20mm. The functional scores did not zshow a significant correlation with the grading of subluxation.
Lowered by more than 5 mm Restored Elevated more than 5 mm
A scale of −2 to +2 was used to measure different degrees of skin hypo or hyperaesthia. A purpose-designed grid, designed to fit different knee sizes, was used to record sensations. A computer programme was created to record all patients’ data including the length and shape of the incision in relation to anatomical landmarks. A parallel histological study was carried out on 18 skin specimens taken from the 2 standard incisions. The specimens were prepared and stained for nerve endings. The number of nerve endings in each incision was calculated.
Joint line elevation >
8mm has been associated with inferior clinical outcome, and depression associated with retropatellar pain and increased risk of patella subluxation. Recently, modifications have been made to the Kine-max-Plus Total Knee System instrumentation, theoretically providing better internal fixation to prevent a varus cut and a 12 mm measured resection from the “normal” tibial plateau. This study aims to examine whether these changes result in an improvement in alignment, and a more reliable restoration of joint line.
The diagnoses recorded were: Lateral facet PFOA 227 Symmetrical PFOA 95 Medial facet PFOA 24 Dislocation 15 Subluxation 33 Post traumatic 6 Trochlear dysplasia was noted either retrospectively or as “other diagnosis” in only 10 cases between 1989 and 2003, however in the last year, the condition became recognised locally, and has been recorded in 11 of the 48 cases performed. A recent review of 40 cases aged under 55 showed evidence of causative trochlear dysplasia in more than 50%. This was based on: Trochlear dysplasia recorded on operative note 8 A positive crossing sign on a true lateral xray 19 A sulcus angle >
144° 20
Available AP weight bearing radiographs of the knee taken at 8 months and 5 years postoperatively were examined in a random order twice by each of two surgeons who were blinded to the patient details and length of follow up. The severity of arthritis was graded using the classifications of Ahlback and Altman, giving a measure of arthritis progression.
A cohort group of 53 CR Kinemax plus TKR from the Bristol Knee group was matched for age and sex. They had the same parameters measured.
Joint line: elevation K+ LCS 0–2 mm (16/48) = 33% (26/53) = 49% 2–5 mm (14/48) = 29% (14/53) = 26%>
5 mm (18/48) = 38% (12/53) = 25% There was no significant difference in the ROM or Oxford Knee Score when the joint line was not elevated versus elevated for each prosthesis. However, there was suggestion that the ROM in LCS might be more sensitive to joint line changes, although this was not significant. ROM K+ LCS Normal joint line 116° 105° Elevated joint line 108° 101°
There was no significant change in neuropsychiatric outcome from baseline in these patients at 6 weeks or 6 months. Those patients that experienced cerebral microembolisation did not significantly differ in neuropsychiatric outcome from those that did not.
The functional results are similar or better than those of a total knee replacement. Fourteen patients developed mal-alignment (4%) two of which required distal realignment. There have been no cases of deep infection, fracture, wear or loosening. Twenty seven knees (7%) developed evidence of disease progression, twenty two of which (6%) have required revision to a total knee replacement. Nineteen patients (5%) complained of some persistent anterior knee pain of uncertain cause.