Impact of humeral component retroversion on clinical outcomes of reverse total shoulder arthroplasty with humeral lateralization

BackgroundThe effect of humeral component retroversion on clinical outcomes after reverse total shoulder arthroplasty (RTSA) is unclear. Intended retroversion intraoperatively may not produce the same retroversion of the humeral component postoperatively.MethodsThis retrospective study was conducted on consecutive patients who received RTSA using a single product with humeral lateralization at a targeted 25° of humeral retroversion from 2014 to 2019 with minimum 1-year clinical follow-up and postoperative computed tomography (CT). Forty-five patients were enrolled, and humeral component retroversion was measured three-dimensionally. Correlation and regression analyses were conducted between humeral retroversion and postoperative isometric strength and range of motion in forward flexion (FF), external rotation (ER), and internal rotation (IR). Group comparison between a ≤25° group and a >25° group was conducted as sub-analysis to verify possible confounders.ResultsThe actual humeral retroversion was 21.7 ± 11.9°, and it was significantly correlated with postoperative FF [Pearson's correlation coefficient (PCC) = 0.464, P= .003], ER (PCC = 0.481, P = .002), and IR (PCC = 0.471, P = .002) strengths. Multivariable regression analysis showed that humeral retroversion was significantly associated with postoperative FF (Exp(B) = 0.492, P = .003), ER (Exp(B) = 0.336, P = .002), and IR (Exp(B) = 0.578, P = .002) strengths. Two groups in sub-analysis showed no significant difference in pre- or intraoperative variables other than humeral component retroversion. Some functional outcome scores including the Constant score, American Shoulder and Elbow Surgeons score, and activity scales were significantly higher in the >25° group.ConclusionDiscrepancies between intraoperatively targeted humeral retroversion angle and actual postoperative angle after RTSA should be considered by operators and researchers. Increased humeral component retroversion than recommendation can yield acceptable outcomes and might be associated with higher postoperative strength, and possibly with better functional outcome after RTSA with humeral lateralization.Level of evidenceLevel III; Retrospective Comparative Study     

A humeral head cutting guide: instrument to secure correct humeral component retroversion in shoulder joint arthroplasty

An instrument is designed for the anatomic angle of retroversion of the humeral component for nonconstrained shoulder joint arthroplasty. A follow-up study of 18 patients showed correct retroversion in all cases.     

The effect of anteversion on femoral component stability assessed by radiostereometric analysis

Internal rotation of a femoral stem within the femur, with posterior migration of the femoral head (PHM) relative to the femur, is an important mode of failure. The relationship between anteversion and rotational stability for the Exeter (Howmedica International Ltd, London, UK) and Charnley Elite (DePuy International Ltd, Leeds, UK) stems was investigated using radiostereometric analysis (RSA). For the Elite, there was a significant (P=.01) correlation between anteversion and PHM, whereas for the Exeter, there was no significant correlation (P=.6). Increasing anteversion of the Elite was associated with decreasing PHM and increased stability. Of stems, 20% of the Elite and none of the Exeter were classified as having reduced rotational stability because their PHM was >2 SDs from the mean. All reduced rotational stability implants had anteversion substantially <20 degrees. Polished collarless tapered stems such as the Exeter seem to have enhanced rotational stability. For conventional stems, increasing anteversion increases stability. It is recommended that these stems are anteverted 20 degrees.     

Total shoulder arthroplasty with a tissue-ingrowth glenoid component

A newly designed, uncemented, tissue-ingrowth glenoid component with a porous surface was used in association with the Neer humeral head prosthesis for 32 total shoulder arthroplasties in 29 patients. The diagnoses for the shoulders were osteoarthritis in 17, rheumatoid arthritis in eight, and traumatic arthritis in seven. Follow-up evaluations averaged 51 months (range, 29 to 80 months). Five complications occurred, necessitating four reoperations: two for glenoid component dissociation, one for humeral loosening, and one for infection. Little or no pain was experienced after the operation in 27 (96%) of the 28 shoulders that required no additional surgery. Average active abduction was 145°, average external rotation was 59°, and median internal rotation was to 112. Three glenoid components had probable loosening on radiographic examination. Eight shoulders had some degree of instability; a complication related to the glenoid component (polyethylene dissociation) or probable loosening not yet requiring reoperation developed in four of these (p < 0.02). These data support the continuing use of an uncemented, tissue-ingrowth glenoid component in arthritic shoulders with adequate bone support. Joint instability must be avoided to lessen complications and the need for revision surgery.     

Effectiveness of glenoid osteotomy in atraumatic posterior instability of the shoulder associated with excessive retroversion and flatness of the glenoid

 In this investigation, patients with atraumatic posterior instability of the shoulder were appraised in order to evaluate the effectiveness of glenoid osteotomy in the correction of excessive retroversion and flatness of the glenoid. In a series of 32 patients, 17 with posterior instability had no history of trauma. Posterior glenoid osteotomy was performed to correct excessive retroversion and to deepen the glenoid; 95% were re-examined after 5 years. In 81% the results were rated as good or excellent (Constant-Murley and Rowe scores), only 12,5% having had a recurrence. The glenoid could be deepened and on average the angle could be altered from −9.35° to −4,62°. In comparison, 50 volunteers had average angles of −4,4°, thus differing significantly from the preoperative group. Twenty-five per cent of the patiens showed postoperative degenerative changes in the glenohumeral joint. The study shows that excessive retroversion and flatness of the glenoid in persons with atraumatic posterior instability can be successfully treated by a posterior glenoid osteotomy. Nevertheless, the high rate of postoperative degenerative changes must be taken into account.

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Rèsumè  Dans cette étude, nous avons examiné l’efficacité de l’ostéotomie glénoidienne, pour la correction d’une retroversion excessive et d’un défaut de concavité glénodienne, chez les patients souffrant d’une instabilité postérieure de l’épaule non-traumatique. 17 des 32 patients n’ont pas eu d’antécédents traumatiques. L’ostéotomie postérieure glénoidienne a été realisée pour corriger l’excés de retroversion et pour rendre concave la cavité glenoidienne. 95% des malades ont été revus à plus de 5 ans de recul. 81% des resultats ont été classé bons ou excellents, seulement 12.5% ont recidivé. La gléne a pu étre rendue concave et l’angle de rétroversion est passé en moyenne de −9.35°à−4.62°. En comparaion, un groupe de 50 volontaires avait en moyenne 4.4°, ce qui diffère significativement du groupe de patients en préopératoire. 25% des malades ont évolués vers une arthrose gléno humérale. Cette étude montre que l’excés de retroversion et le défaut de concavité associés à une instabilité posterieure de l’épaule atraumatique peut ètre traité par une ostéotomie posterieure de la glène avec un excellent résultat dans la plupart des cas. Mais cependant un pourcentage important d’évolution arthrosique de l’articulation gléno-humérale doit ètre pris en considération.

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Accepted: 22 July 1998     

The development of humeral head retroversion

Humeral head retroversion is important in a variety of clinical situations, but it is not known when retroversion actually develops to adult values. In utero and at birth, the humeral head is known to be in marked retroversion. It derotates sometime thereafter to assume the more standard value with which orthopedic surgeons are familiar. By studying a unique collection of children's bones (180 humeri), I have been able to determine that the greater part of this process takes place, on average, by the age of 8 years (SD +/- 2.12 years); from then on, however, the development continues more slowly until the final adult dimensions are reached, as heralded by the appearance of the radial groove at approximately 16 years of age. This process, along with its timing, appears to be similar, but opposite in direction to, the derotation process that is known to take place in the hip. It has not previously been documented in the shoulder.     

Revision shoulder arthroplasty for glenoid component loosening

Although glenoid component loosening has been recognized as a common reason for failure after total shoulder arthroplasty, there are few studies on the outcome of revision surgery for this problem. The purpose of this study is to determine the outcome of patients who underwent revision for glenoid component loosening. Between 1976 and 2002, 68 shoulders in 66 patients underwent revision for glenoid loosening at our institution. Group I consisted of 33 shoulders that underwent placement of a new glenoid component, and group II consisted of 35 shoulders that had removal and bone grafting without glenoid reimplantation. Follow-up averaged 3.8 years for group I and 6.2 years for group II. There was significant overall improvement in pain from preoperatively to postoperatively in both groups (P = .0001). Pain relief occurred in 23 of 33 shoulders in group I and in 24 of 35 in group II (P = .9203). Regarding range of motion, there was no significant change from preoperatively to postoperatively (P > .05), except for active elevation in group I (P = .0387). Patient satisfaction occurred in 24 in group I and in 19 in group II (P = .1150). The rate of survival free of reoperation at 5 years was 91% (95% confidence interval, 81% to 100%) in group I and 78% (95% confidence interval, 63% to 96%) in group II (P = .3019). When the Neer result rating was applied, 9 shoulders in group I and 3 in group II had an excellent or satisfactory result (P = .0432). Twenty shoulders had late positive cultures, most commonly, Propionibacterium acnes. Glenoid revision surgery will often lead to pain relief and patient satisfaction. There is a slight clinical benefit to reimplanting a glenoid component whenever structurally possible. Positive cultures in revision surgery are common, with uncertain clinical significance.     

The effect of glenoid inclination on superior humeral head migration

Superior humeral head migration may contribute to the development of rotator cuff disease. The purpose of this study was to test the hypothesis that superior inclination of the glenoid facilitates superior humeral head migration. Eight cadaveric shoulders were tested by use of a custom test fixture, and rotator cuff forces were applied. Glenoid inclination was varied (intact, +5 degrees, +10 degrees, and +15 degrees ), and the force required to produce superior humeral head migration was measured. Each increase in glenoid inclination (more superiorly facing glenoid) produced significant reduction in the force required for superior humeral head migration (5 degrees, 14.2% reduction; 10 degrees, 29.9% reduction; and 15 degrees, 37.5% reduction; P <.001). These findings demonstrate that glenoid inclination is an important factor in determining the force required for superior humeral head migration. This suggests that a more upward-facing glenoid increases the risk for superior humeral translation and, in turn, may play a role in the development of rotator cuff disease.