Opening wedge high tibial osteotomy (OWHTO) is a treatment option for medial compartment osteoarthritis of the knee in the young active adult. Limited evidence exists in the literature regarding return to activities following OWHTO. We performed a retrospective study of local patients who underwent OWHTO from 2005 – 2012 assessing post-operative return to sporting function. Patients with additional knee pathology, surgery or alternative issues affecting activity were excluded. 110 patients met inclusion criteria, 75 were successfully contacted. Mean improvement in pain score = 4.8/10 (95%CI 4.2 to 5.4, p<0.01). Mean pre-operative KOS-SAS score = 0.5/2, mean post-operative KOS-SAS score = 1.1/2, mean change in KOS-SAS score following OWHTO = 0.6 (95% CI 0.5 to 0.7, p<0.01). Mean pre-morbid Tegner score = 5.9/10, pre-operative = 2.7/10, post-operative = 4.2/10. Mean change in Tegner score following OWHTO = 1.5 (95% CI 1 to 1.9, p<0.01). Following OWHTO 25% of patients achieved pre-morbid Tegner scores. Patient BMI, age, type of implant or graft used had no significant effect on outcome. OWHTO can temporarily improve pain, activity and sporting levels in young patients with isolated medial compartment knee OA. Return to pre-morbid activity levels and even high level sports function is possible although not the norm.
Limited literature exists providing comprehensive assessment of complications following opening wedge high tibial osteotomy (OWHTO). We performed a retrospective study of local patients who underwent OWHTO for isolated medial compartment knee osteoarthritis from 1997–2013. One hundred and fifteen patients met inclusion criteria. Mean follow-up = 8.4years. Mean age = 47 (range 32–62). Mean BMI = 29.1 (range 20.3–40.2). Implants used included Tomofix (72%), Puddu plate (21%) and Orthofix (7%) (no significant differences in age/ sex/ BMI). Wedge defects were filled with autologous graft (30%), Chronos (35%) or left empty (35%). Five year survival rate (conversion to arthroplasty) = 80%. Overall complication rate = 31%. 25% of patients suffered 36 complications including minor wound infections (9.6%), major wound infections (3.5%), metalwork irritation necessitating plate removal (7%), non-union requiring revision (4.3%), vascular injury (1.7%), compartment syndrome (0.9%), and other minor complications (4%). No thromboembolic complications were observed. A higher BMI (mean 34.2) was apparent in those patients suffering complications than those not (mean 26.9). No significant differences existed in complication rates relative to implant type, type of bone graft used or patient age at surgery. Complications following OWHTO appear higher than previously reported in the literature; serious complications appear rare.
We sought to validate a method of measuring the range of motion of knees on radiographs as part of a new system of “Virtual Knee Clinics”. The range of motion of 52 knees in 45 patients were first obtained clinically with goniometers and compared to radiographs of these patients' knees in full active flexion and extension. Four methods of plotting the range of motion on the radiographs were compared. The intra-class correlation coefficient (ICC) for inter-rater reliability using the goniometer was very high; ICC=0.90 in extension and 0.85 in flexion. The best ICC for radiographic measurement in extension was 0.86 indicating substantial agreement and best ICC in flexion was 0.95 (method 4). ICC for intra-rater reliability was 0.98 for extension and 0.99 for flexion on radiographic measurements. Measuring range of motion of the knee has never previously been validated in the literature. This study has allowed us to set up a “Virtual Knee Clinic,” combining postal questionnaires and radiographic measurements as a surrogate for knee function. We aim to maintain high quality patient surveillance following knee arthroplasty, reduce our new to follow-up ratios in line with Department of Health guidelines and improve patient satisfaction through reduced travel to hospital outpatients.
We report the largest multicentre series analysing the use of bone scans investigating painful post-operative Total Knee Replacements (TKR). We questioned the usefulness of reported scintigraphic abnormalities, and how often this changed subsequent management. 127 three-phase bone-scans were performed during a two-year period. Early and late flow phases were objectively classified. Reported incidences of infection and loosening were determined. Reports were subjectively summarised and objectively analysed to establish the usefulness of this investigation. Eight cases were excluded. Scans were classified as: 33% (39) normal, 53% (63) as possibly abnormal, 6% (7) probably abnormal, and 8% (10) as definitely abnormal. Thirteen patients (11%) underwent revision TKR surgery. Intra-operative analysis revealed loosening of one femoral component, and massive metallosis of the patella in another. Cultures were negative in all cases. The sensitivity and specificity of a definitely abnormal investigation in predicting need for revision surgery was 23% and 82% (respectively). High instances of ambiguously reported abnormalities were observed. This investigation has no role to play in the routine investigation of a painful TKR. It is unnecessary in investigation of periprosthetic infection and should not be used in a routine assessment of a painful TKR. If used it should be limited until an experienced revision surgeon has made a full assessment.
Patellar instability is a complex, multi-factorial disorder. Radiological assessment is regarded as an important part of the management of this population. The purpose of this study was to determine the intra- and inter-rater reliability of common radiological measurements used to evaluate patellar instability. One hundred and fifty x-rays from 51 individuals were reviewed by five reviewers: two orthopaedic trainees, a radiological trainee, a consultant radiologist and an orthopaedic physiotherapist. Radiological measurements assessed included patellar shape, sulcus angle, congruence angle, lateral patellofemoral angle (LPA), lateral patellar displacement (LPD), lateral displacement measurement (LDM), boss height, and patellar height ratios (Caton-Deschamps, Blackburne-Peel, Insall-Salvati). All assessors were provided with a summary document outlining the method of assessing each measurement. Bland-Altman analyses were adopted to assess intra- and inter-rater reliability.Background
Methods
Great expense is accumulated in investigation and management, often with poor outcome, of a patient with a painful TKR. We aim to produce guidelines for their investigation and careful, successful management. We studied 42 cases of patients with a painful TKR. Costs were calculated of appointments, serological and radiological investigations for these patients and an average cost of investigating a patient was obtained. We also calculated costs of various forms of management, both surgical and non-surgical and correlated these with patient outcomes.Purpose
Method
ARMD (Adverse Reaction to Metal Debris) is an increasingly recognised complication of metal on metal hip replacements. The MHRA (Medical and Healthcare Related Devices Agency) have advised a blood cobalt or chromium level above 7 mg/L is a threshold for further investigation, stating that “low levels are reassuring and strongly predict not having an adverse outcome”. Cross-sectional imaging should be performed when levels are above 7 mg/L. We have performed a study investigating the specificity and sensitivity of chromium and cobalt metal ion levels as a screening measure for ARMD. 79 ASR hip replacements were performed at our hospital and 75 (95%) of these underwent a Metal Artefact Reduction Sequence (MARS) MRI scan. All patients (64 hips) who had not undergone revision were invited to take part in this study. 57 patients with 62 hip replacements completed hip and activity scores, had blood cobalt and chromium ion level measurements and 3D-CT to measure acetabular component position. Acetabular component inclination (>50 degrees), small head size (< 51mm) and female gender were significantly correlated with raised chromium (Cr) and cobalt (Co) ion levels. An ARMD was detected using MRI in 18 (29%) of the hips in this study. The incidence of ARMD was significantly higher when chromium concentration was above 7 mg/l (p = 0.02). Chromium ion levels >7 mg/L had a sensitivity of 56% and specificity of 83% for ARMD, and cobalt ion levels >7 mg/L 56% and 76% respectively. 40 patients had cobalt levels <7 mg/L and 33 had chromium levels <7 mg/L, but 8 of these had an ARMD on MRI. All 8 patients had minimal symptoms (Oxford Hip Score ≥ 44 out of 48). The Medicines and Healthcare Products Regulatory Agency (MHRA) has recommended that cobalt and chromium levels be measured in patients with a metal-on-metal hip replacement and cross-sectional imaging performed when these levels are above 7 μg/L. This study has shown that by using this threshold, in patients with this implant combination, the sensitivity and specificity for the detection of ARMD is low and patients with soft tissue disease may be missed. Furthermore the presence of MRI detected ARMD, in the absence of significant clinical symptoms and with metal ion levels <7 μg/L is of concern. MoM implants at risk of failure are associated with raised cobalt and chromium levels. However metal ion analysis alone is not reliable as a screening tool for ARMD, which is often clinically “silent”. We recommend the routine use of MARS MRI as the safest method of ARMD diagnosis in patients with MoM implants.
