Surgical repair of the rotator cuff: a biomechanical evaluation of different tendon grasping and bone suture fixation techniques Massimiliano Baleani a, * , Stephan Schrader a , Carlo Andrea Veronesi b , Roberto Rotini b , Roberto Giardino c , Aldo Toni a,d a Laboratorio di Tecnologia Medica, Istituti Ortopedici Rizzoli, Via Di Barbiano 1/10, 40136 Bologna, Italy b Modulo Dipartimentale Chirurgia Spalla-Gomito, Istituti Ortopedici Rizzoli, 40136 Bologna, Italy c Servizio di Chirurgia Sperimentale, Istituti Ortopedici Rizzoli, 40136 Bologna, Italy d I Divisione Ortopedia e Traumatologia, Istituti Ortopedici Rizzoli, 40136 Bologna, Italy Received 28 January 2002; accepted 28 May 2003 Abstract Objective. This study investigated the initial strength and failure mode of different rotator cuff repair techniques. Background. Full or partial re-rupture of the repair is one of the main post-operative complications for rotator cuff repair. The rate of failure is strongly affected by the extension of the tear, increasing in case of large or massive tears up to 62%. Design. The study was planned to assess the three individual components of the tendon-to-bone repair (tendon grasping, suture knotting, suture-to-bone fixation) and to identify the best combinations in terms of mechanical strength to failure. The best combinations were tested to compare the mechanical behaviour of the entire repair and suggest potential improvements in the repair technique. Methods. Experimental tests were performed using sheep shoulders. Three tendon-grasping techniques, two suture knotting techniques, and the effect of bone augmentation with metallic plate and bone quality on suture-to-bone fixation were investigated. Results. This study assessed the mechanical behaviour of different repair components. The best combinations of the investi- gated techniques showed that the weakest link was the tendon–suture interface. More importantly, the compliance of the investigated repairs was large. Conclusions. The initial strength of the rotator cuff repair can be improved by changing the repair technique. Nevertheless, even a low physiological load stressing the repaired tendon may cause a gap formation at the tendon–bone interface without necessarily producing failure of the repair. Relevance Post-operative protection of the repaired rotator cuff from tension load is necessary to reduce the risk of delaying or preventing of the healing process. Ó 2003 Elsevier Ltd. All rights reserved. Keywords: Rotator cuff; Repair technique; Biomechanics; Experimental testing; Tensile strength; Stiffness 1. Introduction Lesion of the rotator cuff is a common problem in orthopaedics. Progressive pain or functional deficits to the shoulder joint generally requires surgical repair of the rotator cuff. Traditional techniques for the repair of the rotator cuff have evolved from the work of McLaughlin (1944). McLaughlin described a surgical method for the reattachment of the avulsed rotator cuff tendon to the humeral bone by passing sutures through transosseous tunnels in the greater tuberosity. Although others have subsequently studied the use of different fixation techniques, trying to obtain a greater strength of fixation or to define a less invasive technique (Craft et al., 1996; France et al., 1989; Goradia et al., 2001; Hecker et al., 1993; Gerber et al., 1994; Reed et al., 1996; Rossouw et al., 1997), the modified McLaughlin tech- nique and subacromial decompression is still widely * Corresponding author. E-mail address: baleani@tecno.ior.it (M. Baleani). 0268-0033/$ - see front matter Ó 2003 Elsevier Ltd. All rights reserved. doi:10.1016/S0268-0033(03)00122-0 www.elsevier.com/locate/clinbiomech Clinical Biomechanics 18 (2003) 721–729