Recovery after unilateral knee replacement due to severe osteoarthritis and progression in the contralateral knee: a randomised clinical trial comparing daily 2000 IU versus 800 IU vitamin D.

OBJECTIVE: To test whether daily high-dose vitamin D improves recovery after unilateral total knee replacement. METHODS: Data come from a 24-month randomised, double-blind clinical trial. Adults aged 60 and older undergoing unilateral joint replacement due to severe knee osteoarthritis were 6-8 weeks after surgery randomly assigned to receive daily high-dose (2000 IU) or standard-dose (800 IU) vitamin D3. The primary endpoints were symptoms (Western Ontario and McMaster Universities Arthritis Index pain and function scores) assessed at baseline, 6, 12, 18 and 24 months in both knees, and the rate of falls over 24 months. The secondary outcomes were sit-to-stand performance, gait speed, physical activity and radiographic progression in the contralateral knee. RESULTS: We recruited 273 participants, 137 were randomised to receive 2000 IU and 136 were randomised to receive 800 IU vitamin D per day. 2000 IU vitamin D increased 25-hydroxyvitamin D levels to 45.6 ng/mL and 800 IU vitamin D to 37.1 ng/mL at month 24 (p<0.0001). While symptoms improved significantly in the operated knee and remained stable in the contralateral knee over time, none of the primary or secondary endpoints differed by treatment group over time. The rate of falls over 24 months was 1.05 with 2000 IU and 1.07 with 800 IU (p=0.84). 30.5% of participants in the 2000 IU and 31.3% of participants in the 800 IU group had radiographic progression in the contralateral knee over 24 months (p=0.88). CONCLUSIONS: Our findings suggest that a 24-month treatment with daily 2000 IU vitamin D did not show greater benefits or harm than a daily standard dose of 800 IU among older adults undergoing unilateral total knee replacement.

The use of the Core Outcome Measures Index (COMI) in patients undergoing total knee replacement.

BACKGROUND: The Core Outcome Measure Index (COMI) is a very short outcome instrument used in spine patients. The aim of this study was to examine the utility of a knee version of the COMI in patients undergoing total knee arthroplasty (TKA) by assessing the reproducibility, construct and discriminant validity, and responsiveness. METHODS: Preoperatively, 224 patients completed the Oxford Knee Score (OKS), EuroQoL (EQ-5D) and the COMI-Knee; 189 (84) % also completed the questionnaires at follow-up and 73 patients completed preoperatively the COMI-knee twice. RESULTS: The weighted kappa values for the COMI-knee single items ranged from 0.80 to 0.89 and the ICC for the COMI-knee (composite score), 0.86. The absolute SEM for COMI-knee was 0.4 points, i.e. four percent of the maximum value (10 points) and six percent of the average value (6.6 points). The Area Under the Curve derived from the Receiver Operating Characteristic method for the COMI-knee was 0.97 (95% CI, 0.93 to 0.99), with a cut-off value for indicating a "good" result of 2.3 (100% specificity, 87% sensitivity). Correlations between the COMI-knee and the OKS were -0.72 at baseline and -0.87 at six months. The correlations between the change scores for the COMI-knee and the change scores for the OKS and EQ5D index were 0.77 and 0.69, respectively. CONCLUSIONS: The measurement properties of the COMI-knee satisfy international quality criteria and hence support its use in assessing patients undergoing TKA.

A titanium plasma-sprayed cup with and without hydroxyapatite-coating: a randomised radiostereometric study of stability and osseointegration.

We present a prospective, two-centre radiostereometric analysis (RSA) regarding the stability of a flattened pole titanium press-fit cup (EP-FIT PLUS), and whether additional hydroxyapatite coating leads to faster bone ingrowth into the porous coating. Forty-two postmenopausal female patients (44 hips) undergoing total hip arthroplasty for primary osteoarthritis, selected to avoid hormonal factors influencing bone metabolism, were randomised to receive this cup with a titanium-plasma-sprayed surface with or without an additional hydroxyapatite coating. RSA was used to measure cup translation and rotation along three cardinal axes with respect to the host bone at the following time points: immediately postoperatively, at 6 weeks, and at 3, 6, 12, and 24 months. The most pronounced translation was proximal (0.11 mm) and posterior tilt (-0.27°). No difference in translation and rotation could be detected between the two groups. With the exception of one cup with an isolated radiolucent line <2 mm in zone 1, all cups showed complete osseointegration on conventional radiographs. The flattened pole cup provided excellent early stability and no advantage could be detected with additional hydroxyapatite coating.

The effect of femoral component rotation on the five-year outcome of cemented mobile bearing total knee arthroplasty.

PURPOSE: Performing total knee replacement, accurate alignment and neutral rotation of the femoral component are widely believed to be crucial for the ultimate success. Contrary to absolute bone referenced alignment, using a ligament balancing technique does not automatically rotate the femoral component parallel to the transepicondylar axis. In this context we established the hypothesis that rotational alignment of the femoral component parallel to the transepicondylar axis (0° ± 3°) results in better outcome than alignment outside of this range. METHODS: We analysed 204 primary cemented mobile bearing total knee replacements five years postoperatively. Femoral component rotation was measured on axial radiographs using the condylar twist angle (CTA). Knee society score, range of motion as well as subjective rating documented outcome. RESULTS: In 96 knees the femoral component rotation was within the range 0 ± 3° (neutral rotation group), and in 108 knees the five-year postoperative rotational alignment of the femoral component was outside of this range (outlier group). Postoperative CTA showed a mean of 2.8° (±3.4°) internal rotation (IR) with a range between 6° external rotation (ER) and 15° IR (CI 95). No difference with regard to subjective and objective outcome could be detected. CONCLUSION: The present work shows that there is a large given natural variability in optimal rotational orientation, in this study between 6° ER and 15° IR, with numerous co-factors determining correct positioning of the femoral component. Further studies substantiating pre- and postoperative determinants are required to complete the understanding of resulting biomechanics in primary TKA.

Five-year results of the Innex total knee arthroplasty system.

The clinical and radiographic results of 174 female and 86 male Innex (Zimmer, Warsaw, Indiana) mobile bearing total knee arthroplasty systems (245 patients) were evaluated, with particular emphasis on gender-related differences at five-year follow-up. Pre-operative Knee Society (KS) function and total scores were lower in women than in men. All KS scores showed a significant improvement at follow-up, but women still obtained lower KS function scores than men. Self-reported function was significantly better for male knees. No gender differences were observed for component alignment, while the occurrence of radiolucent lines, endosteal cavitations, and wear was significantly greater in male knees. Male Innex mobile bearing knees exhibited better clinical function and satisfaction than their female peers at five-year follow-up, despite inferior radiographic findings and higher revision rates.

Reconstruction of severe uncontained bone defects in revision total knee arthroplasty in a patient with rheumatoid arthritis.

We report on a 54-year-old rheumatoid arthritic female patient with uncontained type-III tibial and femoral bone defects at the time of revision total knee arthroplasty (TKA). The knee was reconstructed using a structural distal femoral allograft and a stemmed, semi-constrained knee prosthesis. We achieved the re-alignment of a severe preoperative valgus deformity of 40 degrees. Due to postoperative wound complications we had to perform a gastrocnemius muscle flap. At two-year follow-up the patient was free of pain and the Knee Society Score improved from 18 to 156 (p < 0.01). Radiographs revealed no loosening of the prosthetic components and progressive incorporation of the graft. Reconstruction of extensive uncontained bone defects in revision of TKA in rheumatoid arthritis can be managed by structural allografts; however, wound complications in those patients might necessitate soft tissue techniques.