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Journal Club

May 2010

Vitamin D deficiency in patients with osteoarthritis undergoing total hip replacement

• Authors: D. H. Nawabi, K. F. Chin, R. W. Keen, F. S. Haddad
• Institution: University College London Hospital NHS Trust, London, England
• Journal: J Bone Joint Surg [Br] 2010;92-B:362-6, VOL. 92-B, No. 4, APRIL 2010

Introduction

• Vitamin D in THJR
  
  • Decreased in OA populations (Lane et al 1999, Felson et al 2007, & Glowacki et al 2003.)
  • Mutation in Vitamin D receptor correlates with aseptic loosening and prosthesis failure (Malik 2007)
• Aims
  
  • No functional studies
  • Measure vitamin D in a population undergoing THJR
  • Correlate to function

Methodology

• Patients n = 62
  
  • Over a 3/12
    
    • Vitamin D measured pre op
      
    • Harris Hip Score (HHS) measured pre (2/52) & post op (6/12)
      
  • Study design
    
    • Same surgeon, prosthesis
      
    • Same Dr. completed HHS
      
    • Caucasians only
      
    • No Vitamin D supplements

Results

• Vitamin D levels
  • Vitamin D >40
    • 15 patients
      
    • Preop HHS 32*
    • Postop HHS 85
  • Vitamin D <40
    • 47 patients
      
    • Preop HHS 42*
    • Postop HHS 89
      
      • * statistically different between Vit D groups
  • HHS (90-100) postop
    • 31 pt excellent HHS
      
      • Vitamin D 67.5 nmol/l (sd 27.5) *
  • HHS <90 postop
  • 31 pt
    
    • Vitamin D 48.6 nmol/l (sd 19.2) *
      
      • * statistically different between HHS groups
  • Positive correlation between vitamin D both pre and post op HHS

Discussion

• Decreased Vitamin D
  • increases degradative proteinases (Dean et al 1996)
    
  • Therefore loss of balance between synthesis and degradation of articular cartilage.
• Slow re-modelling (Radin & Rose 1986)
  
  • Therefore thickened subchondral bone, osteophytes and cartilage damage
• Conclusions
  • Prevalent
    
  • Predicts poor pre op function
    
  • May predict post op functional outcome
    
  • Suggest trials of Vitamin D with THJR
    
    • Simple
      
    • Safe
      
    • Well tolerated
      
    • Inexpensive

Pros of Study

• Raises interesting question about Vitamin D

Cons of Study

• No cause or effect
• No basis to suggest Vit D is related to outcome
• Need more studies
  
  • Vitamin D supplementation (good suggestion)
    
  • Epidemiological studies
    
  • Different populations

Consultant Discussion

• Interesting idea to do randomised study
• Should we routinely be checking Vitamin D in our preoperative patients?
• Raises interesting questions
  • 15% with Vitamin D deficiency
    • Decreased pre op HHS
      
      • Decreased function?
        
      • Decreased activity?
        
      • Decreased sunlight exposure?