The B2 glenoid and "version correction"

Eccentric Reaming for B2 Glenoids: Historical past, Preoperative Planning, Surgical Method, and Consequence

These authors focus on the biconcave (B2) glenoid, characterised by preservation of the anterior portion of the native glenoid with uneven put on of the posterior glenoid. They level to the significance of returning the humeral head to a centered place on the glenoid. 

They counsel that uneven remaining can be utilized to handle as much as 15 of model correction with out compromise of cortical bone. 
The advocate for the usage of preoperative CT scans
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And 3D planning software program

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Nevertheless, in reviewing their case instance one could make serval observations:
(1) the preoperative CT scan

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didn’t reveal the pathoanatomy as clearly because the preoperative axillary view

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and
(2) of their case instance of “corrective reaming”, the model of the glenoid was not modified from earlier than surgical procedure

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to after surgical procedure

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and
(three) the prosthetic humeral head is centered on the humeral head regardless of 30 levels of postoperative glenoid retroversion (measure it your self).

We conclude that what issues is centering of the humeral head on the glenoid and preservation of glenoid bone inventory. These objectives will be achieved in nearly all instances with out preoperative CT planning and with out “corrective reaming” or augmented glenoids.

Extra on this subject will be see right here:
Outcomes of anatomic complete shoulder arthroplasty in sufferers with extreme glenoid retroversion: a case-control examine 

These authors used a case-controlled examine to judge the impact of  extreme preoperative glenoid retroversion on medical and radiographic complete shoulder (TSA) outcomes utilizing a regular non-augmented glenoid element.

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They in contrast 40 sufferers with greater than 20 of glenoid retroversion preoperatively (common follow-up, 53 months) vs. a matched cohort of 80 sufferers with lower than 20 of retroversion (common follow-up, 49 months). In all sufferers, the surgical approach, implant design, and postoperative rehabilitation protocol have been equivalent. Peg parts have been predominantly used until the glenoid vault was decided to be slender based mostly on preoperative imaging. There have been 2 keeled glenoid parts used within the retroversion group and 5 keeled glenoid parts used within the management group. The glenoid was ready utilizing noncannulated reaming instrumentation with a aim of making ready the glenoid floor to create a minimal of 80% bottom concentric assist with out violation of subchondral bone assist. In instances of eccentric put on, the glenoid was reamed to match the bottom of the glenoid element, sometimes preferentially reaming the anterior glenoid and partially correcting glenoid model. Sufferers have been matched based mostly on intercourse, age, indication, and prosthetic measurement.

Preoperatively and postoperatively, each teams demonstrated related affected person reported final result measures and measured movement.

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No vital variations have been noticed within the postoperative radiographic findings. Postoperative glenoid model was not measured, so the diploma of “partial correction” isn’t identified.

The authors concluded that at midterm follow-up, preoperative extreme glenoid retroversion doesn’t seem to affect medical or radiographic outcomes of TSA utilizing a regular glenoid element.

Remark: It’s of be aware main business has sprung up round measuring and managing preoperative glenoid retroversion. Against this, the authors of this paper didn’t use a information wire positioned based mostly on preoperative measurements and as an alternative adjusted their glenoid reamer to supply a single concavity with minimal bone elimination.

This paper will be thought-about together with the one described beneath wherein postoperative glenoid retroversion was measured and located to not have a adverse impact on the result.

Does Postoperative Glenoid Retroversion Have an effect on the 2-Yr Medical and Radiographic Outcomes for Whole Shoulder Arthroplasty?

Whereas glenoid retroversion and posterior humeral head decentering are frequent preoperative options of severely arthritic glenohumeral joints, the connection of postoperative glenoid element retroversion to the medical outcomes of complete shoulder arthroplasty (TSA) is unclear. Research have indicated concern for inferior outcomes when glenoid parts are inserted in 15° or extra retroversion.

In a inhabitants of sufferers present process TSA in whom no particular efforts have been made to vary the model of the glenoid, these authors requested whether or not at 2 years after surgical procedure sufferers having glenoid parts implanted in 15° or higher retroversion had (1) much less enchancment within the Easy Shoulder Check (SST) rating and decrease SST scores; (2) greater percentages of central peg lucency, greater Lazarus radiolucency grades, greater imply percentages of posterior decentering, and extra frequent central peg perforation; or (three) a higher share having revision for glenoid element failure in contrast with sufferers with glenoid parts implanted in lower than 15° retroversion. They examined the data of  201 TSAs carried out utilizing a regular all-polyethylene pegged glenoid element

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inserted after conservative glenoid reaming with out particular try to switch preoperative glenoid model.
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Of those, 171 (85%) sufferers had SST scores preoperatively and between 18 and 36 months after surgical procedure. Ninety-three of those sufferers had preoperative radiographs within the database and speedy postoperative radiographs and postoperative radiographs taken in a spread of 18 to 30 months after surgical procedure. Twenty-two sufferers had radiographs that have been insufficient for measurement on the preoperative, speedy postoperative, or newest followup time in order that they might not be included. Compared to these included within the evaluation, the excluded sufferers didn’t have considerably completely different imply age, intercourse distribution, time of followup, distribution of diagnoses, American Society of Anesthesiologists class, alcohol use, smoking historical past, BMI,  historical past of prior surgical procedure or preoperative glenoid model. They analyzed the 2 yr outcomes within the remaining 71 TSAs, evaluating the 21 within the retroverted group (the glenoid element was implanted in 15° or higher retroversion (imply ± SD, 20.7° ± 5.three°)) with the 50 within the non-retroverted group ( the glenoid element was implanted in lower than 15° retroversion (imply ± SD, 5.7° ± 6.9°)). 
The imply (± SD) enchancment within the SST (6.7 ± three.6; from 2.6 ± 2.6 to 9.three ± 2.9) for the retroverted group was not inferior to that for the nonretroverted group (5.eight ± three.6; from three.7 ± 2.5 to 9.Four ± three.zero). The p.c of maximal potential enchancment (%MPI) for the retroverted glenoids (70% ± 31%) was not inferior to that for the nonretroverted glenoids (67% ± 44%).  The two-year SST scores for the retroverted (9.three ± 2.9) and the nonretroverted glenoid teams (9.Four ± three.zero) have been related (imply distinction, zero.2; 95% CI, – 1.1 to 1.Four; p = zero.697). No affected person in both group reported signs of subluxation or dislocation. The radiographic outcomes for the retroverted glenoid group have been much like these for the nonretroverted group with respect to central peg lucency (4 of 21 [19%] versus six of 50 [12%]; p = zero.436; odds ratio, 1.7; 95% CI, zero.Four-6.9), common Lazarus radiolucency scores (zero.5 versus zero.7, Mann-Whitney U p worth = zero.873; Wilcoxon rank sum check W = 512, p worth = zero.836), and the imply share of posterior humeral head decentering (three.Four% ± 5.5% versus 1.6% ± 6.zero%; p = zero.223). The share of sufferers with retroverted glenoids present process revision (zero of 21 [0%]) was not inferior to the share of these with nonretroverted glenoids (three of 50; [6%]; p = zero.251).

The authors concluded that on this collection of TSAs, postoperative glenoid retroversion was not related to inferior medical outcomes at 2 years after surgical procedure. 

Remark:  Glenoid retroversion is a comparatively frequent discovering in arthritic glenohumeral joints coming to shoulder arthroplasty. Shoulders with preoperative glenoid retroversion are inclined to have poorer preoperative shoulder consolation and performance, posterior decentering, and glenoid biconcavity, all indicating a extra extreme type of the illness. There may be presently nice curiosity in strategies for altering this glenoid retroversion that’s generally present in osteoarthritic glenohumeral joints. Strategies used embody posterior glenoid bone grafts, reaming the anterior side of the glenoid, and posteriorly augmented glenoid parts. This examine stories the 2 yr outcomes of a extra conservative method wherein minimal glenoid bone is eliminated by reaming and particular makes an attempt to change glenoid model aren’t used.
Right here is the 2 yr radiographic followup on a 55 yr previous affected person from our observe. Preoperative movies present a sort B2 genoid with retroversion, biconcavity and posterior humeral subluxation.
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Listed below are the two yr movies of this shoulder after conservative shoulder arthroplasty utilizing a regular glenoid element with out makes an attempt to switch glenoid model. The humeral head is centered within the prosthetic glenoid. At two years after surgical procedure the affected person was capable of carry out all 12 features of the Easy Shoulder Check.
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Be aware that enough bone inventory stays to carry out a revision complete or a reverse complete shoulder arthroplasty shoulder these procedures turn into essential in the way forward for this younger individual.

Long run followup of well-characterized sufferers handled with the completely different strategies for managing glenoid retroversion can be required to outline the relative dangers, advantages, effectiveness and sturdiness of every of them.

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