The use of peripheral locked screws has reduced glenoid baseplate failure rates in reverse shoulder arthroplasty. However, situations may arise when one or more non-locked screws may be preferred. We aimed to determine if different combinations of locked and non-locked screws significantly alter acute glenoid baseplate fixation in a laboratory setting.
Twenty-eight polyurethane trabecular bone surrogates were instrumented with a center screw-type glenoid baseplate and fixated with various combinations of peripheral locked and non-locked screws (1-, 2-, 3- and 4-locked con). Each construct was tested through a 55° arc of abduction motion generating compressive and shear forces across the glenosphere. Baseplate micromotion (μm) was recorded throughout 10,000 cycles for each model.
All constructs survived 10,000 cycles of loading without catastrophic failure. One test construct in the 1-locked fixation group exhibited a measured micromotion >150 μm (177.6 μm). At baseline (p > 0.662) and following 10,000 cycles (p > 0.665), no differences were observed in baseplate micromotion for screw combinations that included one, two, three and four peripheral locked screws. The maximum difference in measured micromotion between the extremes of groups (1-locked and 4-locked) was 29 µm.
Hybrid peripheral screw fixation using combinations of locked and non-locked screws provides secure glenoid baseplate fixation using a polyurethane bone substitute model. Using a glenosphere with a 10-mm lateralized center of rotation, hybrid baseplate fixation maintains micromotion below the necessary threshold for bony ingrowth.
N/A/, basic science investigation.
Kwon YW, Forman RE, Walker PS, Zuckerman JD (2010) Analysis of reverse total shoulder joint forces and glenoid fixation. Bull NYU Hosp Jt Dis 68:273–280 PubMed
Fenlin JM Jr (1975) Total glenohumeral joint replacement. Orthop Clin North Am 6:565–583 PubMed
Gerard Y, Leblanc JP, Rousseau B (1973) [A complete shoulder prosthesis]. Chirurgie 99:655–663 PubMed
Frankle M, Siegal S, Pupello D, Saleem A, Mighell M, Vasey M (2005) The reverse shoulder prosthesis for glenohumeral arthritis associated with severe rotator cuff deficiency. A minimum two-year follow-up study of sixty patients. J Bone Joint Surg Am 87:1697–1705 PubMed
Gardner MJ, Griffith MH, Demetrakopoulos D et al (2006) Hybrid locked plating of osteoporotic fractures of the humerus. J Bone Joint Surg Am 88:1962–1967 PubMed
Sutherland GB, Creekmore T, Mukherjee DP, Ogden AL, Anissian L, Marymont JV (2010) Biomechanics of humerus fracture fixation by locking, cortical, and hybrid plating systems in a cadaver model. Orthopedics 33(8). doi: 10.3928/01477447-20100625-02
Pilliar RM, Lee JM, Maniatopoulos C (1986) Observations on the effect of movement on bone ingrowth into porous-surfaced implants. Clin Orthop Relat Res. 208:108–113
- Glenoid baseplate fixation using hybrid configurations of locked and unlocked peripheral screws
Nathan T. Formaini
Nathan G. Everding
Jonathan C. Levy
Brandon G. Santoni
Aniruddh N. Nayak
- Springer International Publishing
Neu im Fachgebiet Orthopädie und Unfallchirurgie
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