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Journal Club

July 2010

Clinical, Radiographic, and Ultrasonographic Comparison of Subscapularis Tenotomy and Lesser Tuberosity Osteotomy for Total Shoulder Arthroplasty

• Authors: Jason J. Scalise,, James Ciccone, and Joseph P. Iannotti
  
• Institution: Cleveland Clinic, Cleveland, Ohio, USA
• Journal: J Bone Joint Surg Am. 2010;92:1627-1634
• Study Type
  • Retrospective case control seriesaLevel III evidence
    
  • Study not directly funded
    
  • DePuy sponsored research fund/department

 

Introduction

• Subscapularis deficiency after shoulder arthroplasty has a negative effect on long-term outcomes.
• Thus, increasing emphasis has been placed on the technique for repair of the tendon.
  
• Aim
  
  • To assess the difference in functional outcome between subscapularis tenotomy vs lesser tuberosity osteotomy in total shoulder atrhroplasty
    
• Hypotheses
  
  • Mobilizing subscapularis through a lesser tuberosity osteotomy results in better clinical outcome and less subscapularis dysfunction

Methodology

• Outcome Paramaters
  
  • Clinical
    
    • Blinded ROM, Belly press test, 1 year
      
    • Penn shoulder score (pain, satisfaction, function) 1year, 2 years
      
    • Strength
      
      • IR strength at 1 year
        
      • Handheld dynamometer, 3 recorded tests
  • Radiographic
    
    • Preop, 1year.
      
    • Union of tuberosity and adjacent cortices, position
      
    • Prosthetic loosening
      
  • Ultrasound
    
    • 1 year, single operator + surgeon, blinded to technique and outcome.
      
    • Intact/ attenuated > 50% / full thickness tear
      
• Inclusion Criteria
  • Patients with osteoarthritis who underwent primary total shoulder arthroplasty with either a subscapularis tenotomy or lesser tuberosity osteotomy
    
  • Radiographic OA criteria
    
    • Glenohumeral jointspace narrowing
      
    • subchondral sclerosis
      
    • osteophytes
      
• Exclusion criteria
  
  • Inflammatory arthritis, traumatic arthritis, osteonecrosis
    
  • Concomitant rotator cuff tear
    
  • Prior shoulder surgery
    • Hemiarthroplasty
      
  • Immediate postoperative infection
    
  • Deviation from the standard postoperative rehabilitation protocol.
    
• Patients
  • 48 patients
    
    • Consecutive series over 2 year period, same surgeon
      
    • Power analysis of 12 patients
      
    • 14 lost to follow up
      
      • 3 lost, 3 post-op complications, 8 too far away
        
  • 34 divided -stratified by sex
    
    • Group 1 Subscapularis tenotomy
      
      • 15 patients
        
        • 39 months follow up
          
    • Group 2 Lesser tuberosity osteotomy
      
      • 19 patients
        
        • 30 months follow up
          
• Surgical Technique
  
  • Deltopectoral approach
    – biceps tenodesed
    
  • Subscap defined, interval between capsule developed
    
  • Tenotomy
    
    • Dissected off Lesser tuberosity, LT debrided of fibrocartilage
      
    • 2 mm drill hole lateral to LT, bony bridge fibrewire repair
      
  • Osteotomy
    
    • Medial to bicipital groove, parallel to tendon
      
    • Continued to articular surface medially, anatomic neck inferiorly
      
    • Fragment 5 – 10mm thick, 3-4 cm long
      
    • 2mm drill holes, tension band construct around stem
      
  • Global Advantage, cementless the humeral side.
    
• Postop
  • Sling twenty-four hours, passive range-of-motion day 1.
    
  • pendulum exercises, full passive elevation passive external rotation.
    
  • 6 weeks, passive ER limited to 10 deg less than surgery , all patients at least 30.
    
  • At 6 weeks, progressive strengthening, unrestricted range of motion.
    
  • At 12 weeks, ongoing home based program.
• Statistics:
  
  • Student t test
    
    • outcome scores, strength, range of motion, and ultrasound results
      
  • Spearman rank correlation coefficient
    
    • relationships between ultrasound results and the belly-press test.

Results

• Shoulder score (Penn)
  
  • Post operative: Osteotomy 92 vs Tenotomy 81 (p = 0.04) ( PRE-OP 29)
    
  • 1 year: Osteotomy 92 vs Tenotomy 73 (p = 0.01)
    
  • 2 years : Osteotomy 86 vs tenotomy 74 (non-signficant)
    
• Subscapularis
  
  • Intact: Osteotomy 90% vs Tenotomy 53% (p = 0.01)
    
  • Osteotomy 2 attenuated
    • All osteotomies united, no stem loosening
      
  • Tenotomy 6 attenuated, 1 full tear
• External rotation
  
  • Significant improvement in ER both groups (15 to 50)
  • No difference between groups in ER or belly press test.
    
• IR Strength
  
  • Belly test + 3 tenotomy, 1 osteotomy
    
  • No difference between groups between strength when controlled for sex.
    
  • Overall Osteotomy 119 N vs tenotomy 95 N ( p=0.01)

Discussion

• Both techniques clearly resulted in improved clinical outcomes at a minimum two-year follow-up interval
  
• The osteotomy technique resulted in
  • higher total Penn Shoulder Score
  • lower prevalence of subscapularis abnormalities on ultrasonography
  • anatomic healing of the osteotomy in all patients.
    
• Fatty infiltration of subscapularis
  
• May account for similar IR strength
  
• Longer time period may account for adaptation
  
• Longer time period in tenotomy group, allowing tears to account for lower scores

Pros of Study

• First comparison study
  
• 2 year follow up
  
• Consecutive case series
  
• Blinded clinical follow up

Cons of Study

• Retrospective
• Difference in follow up times between groups of 9 months
  
• No ultrasound at 2 year follow up to correlate clinical outcome with.
  
• Possibility of type II error