Complications after RTSA are more common than after conventional total shoulder arthroplasty. The studies reporting these complications are heterogeneous in their methodology making a ranking of the most to the least common complication difficult [18
]. More importantly, information about the relevance of the complications with regard to necessity for revision, as well as to the outcome after revision is sparse. The current study is retrospective and has therefore to be interpreted with caution. From a methodological point of view however, a prospective design for investigation of the relatively rare event of revision needed after RTSA would demand high resources and most probably a multicenter design. For the interpretation of the current data, incomplete documentation with inordinately high loss of follow-up might be a major problem. Lack of documentation was present in this study but only in the personal follow-up of 6 of the 37 patients. They had been reviewed clinically and radiographically in clinic at more than 24
months after their first revision but they were not scored according to Constant and Murley at that period of time. There were, however, no findings in the charts suggesting, that the scores or radiographic outcomes of these six patients would be markedly different from those of the other 31 patients. Another challenge for data interpretation was the multiplicity of indications for revision that could not be addressed by subgroup analysis because of the sample size.
The focus of this study was on the indications for RTSA revision in one specific department with a relatively large experience with RTSA rather than on an enumeration of the frequently discussed complications. In this respect, it is interesting that only one of 67 patients was revised because of inferior notching with contact of the inferior screw with the humeral component which had caused metallosis and pain but not loosening. Conversely there were other reasons that led not surprisingly to an overall high revision rate of 15% for RTSA. The cohort of the patients needing revision after RTSA consisted almost exclusively of those in whom RTSA has been implanted for salvaging situations not amenable to any alternative treatment and involving 100% of shoulders with previous operations (mean of 2
1.4 operations). The revision rate of 15% documented in our cohort is inline with a recent report by Fevang et al.[20
] of 36 revision needed for 225 RTSA (revision rate of 16%), in which the most common reason for revision after RTSA was identified to be aseptic loosening of the glenoid component followed by instability and dislocation. We identified instability as the most common reason for re-intervention after RTSA. This might be caused by the different indications of RTSA; the cohort investigated by Fevang et al.[20
] consisted mainly of patients with inflammatory arthritis while the indication of RTSA in our cohort was mainly an irreparable massive rotator cuff with or without osteoarthritis.
We had started to use the Delta III reverse system in 1996 on a regular basis and changed to another system in 2005. For this study we attempted to eliminate the early phase of our learning curve and started our review with RTSAs which had been implanted no earlier than 1999. The overall revision rate was double as high with the first than with the second reverse system that we used. Although this difference is statistically significant we feel that it is mostly reflection of the fact that our knowledge, understanding and practical experience increased still substantially after 1999.
The most frequent indication for a re-intervention was instability and this for the first, the second and subsequent revisions. Almost all our operations were performed through a deltopectoral approach which has been identified as a risk factor for instability as compared with the superolateral approach [8
]. For this problem, revision triggers have not changed during the study period, but the significantly lower revision rate with the second prosthetic design utilized may be related to better surgical technique and differences in indication. We cannot disagree but also not statistically affirm that early redislocation [8
] can not be successfully treated with closed reduction alone and is probably a problem of component positioning including height of the prosthesis [21
Hematoma and wound dehiscence have previously been identified as an inordinately frequent complication in our environment [12
]. We currently still use two suction drains postoperatively for 48
hours in RTSA to drain the large subacromial space and have reduced postoperative hematoma and wound complications drastically. In revision surgery we will in addition to careful surgical hemostasis also use fibrin sealants to try to avoid hematoma formation and thereby the need for aspiration or revision. We feel that this complication is a truly surgical complication not in relation with the type of reverse implant utilized.
The 31 patients with a minimum follow-up of two years after the first revision who had undergone a mean of 1.8 revisions approximately doubled their Constant-Murley score from the time before RTSA to final follows-up. This was seen also in patients where the reason for revision was an infection. Although the range of motion increased in abduction and remained nearly the same in external rotation, it did not improve internal rotation. This observation has been described to be associated with RTSA [1
] and not specific to patients with revision.
Except for instability, there were no relevant differences between the two prosthetic systems studied. The fact that the revision rate of the second system used was substantially lower was attributed to the increased knowledge concerning indication and increased skill in executing RTSA and may reflect the benefit of surgical experience in RTSA more so [22
] than selecting one or the other system.