Humeral Stem Research Articles

Cause for revision differs between a short and standard length stem at 5 year follow-up

BackgroundThe purpose of this study was to compare the 5 year radiographic and clinical outcomes of anatomic total shoulder arthroplasties (TSA) performed with either a standard length (SL) or short stem. The hypothesis was there would be no difference in radiographic or clinical outcomes based on stem length. MethodsA multicenter retrospective review was performed of primary TSAs performed with a press-fit humeral component. Fifty SL and 72 short stems were available for review, of which 43 SL and 60 short stems had minimum 5 year follow-up. Functional outcome was assessed according to range of motion (ROM), visual analog scale (VAS) American Shoulder and Elbow Surgeons (ASES), and Single Assessment Numeric Evaluation (SANE) scores. Radiographs were reviewed for signs of humeral component loosening and stress shielding. ResultsAt final follow-up there were no differences in ROM, or ASES or SANE scores between groups (P>.05). Postoperative VAS scores were lower in the SL compared to the short stems (0.8 vs. 1.6; P = .053). All-cause revision was similar between the SL and short stems (16% vs. 22.2%; P = .395). Among SL stems there were no revisions for humeral loosening and none were considered radiographically at risk. Six short stems were revised for loosening (8.3%; P =.036 vs. SL). An additional 5 short stems were considered to be radiographically at risk for loosening for a total revision or at risk rate of 15.3% (P = .003 vs. SL). ConclusionThere is no difference in functional outcome at mid-term follow-up of TSA based on stem length with a grit-blasted humeral component. Revision for loosening and radiographic risk for loosening may be higher with a short stem compared a standard length humeral stem placed with press-fit fixation using grit blasting. Level of evidenceLevel III; Retrospective Comparative Study.

The effect of humeral implant thickness and canal fill on interface contact and bone stresses in the proximal humerus.

BackgroundStem size is an important element for successful time zero primary fixation of a press-fit humeral stem in shoulder arthroplasty. Little basic science research, however, has been conducted on the effects of implant thickness and canal fill on load transfer, contact, and stress shielding. The purpose of this finite element study was to determine the effects of varying stem thickness on bone contact, bone stresses, and bone resorption owing to stress shielding.MethodsThree generic short-stem implant models were developed and varied based on cross-sectional thickness (thinner – 8 mm, medium – 12 mm, thicker – 16 mm). Using a finite element model, three outcome measures were determined (1) the amount of bone-to-implant contact, (2) changes in cortical and trabecular bone stresses from the intact state, and (3) changes in cortical and trabecular strain energy densities which can predict bone remodeling or stress shielding.ResultsIncreasing the size of the humeral stem had no significant effects on bone-to-implant contact during loading (P > .07). The thinner implant with the lowest canal fill ratio produced significantly lower changes in stress from the intact state in both cortical and trabecular bone (P < .002). In addition, the thinner implant resulted in a substantially lower volume of bone predicted to stress shield and resorb when compared with the medium and thicker stems.DiscussionThe results demonstrate that thinner implants and lower canal fill may be beneficial over thicker sizes, provided equal initial fixation can be achieved. The thinner implant has a greater degree of load sharing and increases the mechanical load placed on surrounding bone, reducing the risk of stress shielding and bone resorption.

Outcome and revision rate of uncemented humeral head resurfacing: Mid-term follow-up study.

BACKGROUNDGlenohumeral osteoarthritis (OA) is a common cause of pain and disability affecting nearly a third of the world’s population over 60 years of age. As in other joints, shoulder arthroplasty appears to be the most effective treatment. The implant design has evolved during time transitioning to shorter humeral stem lengths or even stemless components.AIMTo evaluate the medium-term outcome and survival of a cementless humeral head resurfacing (HHR) in a group of patients affected with OA or avascular necrosis.METHODSThis is a retrospective study of prospectively collected data using HHR in 23 patients (15 female and 8 male) after a 7.4 year follow-up. The collected data included clinical and radiographical evaluation. The Constant score, the visual analogue scale, and a clinical evaluation of range of motion were registered pre- and postoperatively. Fifteen patients affected with OA (2 cases of mild, 6 moderate, and 7 severe) and 10 with avascular necrosis (stage III according to Cruess classification) were enrolled. X-rays were evaluated to detect loosening signs, degenerative changes, and superior humeral head migration. Magnetic resonance preoperatively was also performed to assess the rotator cuff status. Tendon integrity was mandatory to implant the HHR.RESULTSIn total, 19 patients (21 shoulders) completed the follow-up. Data on 4 shoulders, in 4 patients, were lost because of prosthesis failure. The global revision rate was 16%. A statistically significant improvement in the mean Constant score, visual analogue scale, and range of motion have been reported. No signs of loosening were registered, while in 12 cases a glenoid erosion was found. The osteophytes appeared 7 times on the humeral side and 12 on the glenoid. Superior humeral migration was recorded in only 1 case.CONCLUSIONHHR remains a reasonable option in patients with an intact rotator cuff for the treatment of OA and avascular necrosis.

Symptomatic aseptic loosening of a short humeral stem following anatomic total shoulder arthroplasty.

The rate of aseptic humeral component loosening with standard-length stems is historically so low (0.3%) that presence of humeral loosening was given substantial weight in defining periprosthetic shoulder infection by the International Consensus Meeting (ICM) in 2018. This study aims to confirm that the historically low rate of humeral stem aseptic loosening is not affected by the adoption of a novel short humeral stem. Following institutional review board approval, this retrospective multi-institutional study was undertaken. A review of anatomic total shoulder arthroplasty (TSA) cases at 3 institutions provided 184 shoulders that received TSA with a grit-blasted, rectangular short humeral stem without ingrowth coating (Univers Apex; Arthrex). The average patient age was 62.1 years (range: 30-84), and 57.1% (105/184) were male. One-year radiographic follow-up was achieved in 64.7%. Patient clinical charts were reviewed for onset of newly painful shoulders, radiographic evidence of loosening, and return to the operating room for any reason. All patients with concern for clinically significant humeral loosening underwent workup for periprosthetic shoulder infection. Immediate postoperative films were reviewed to identify any differences in prosthetic canal fit. The definition of periprosthetic shoulder infection used was provided by the recent ICM shoulder guidelines. Twenty-three (12.5%) patients presented with a painful shoulder and radiographic concern for potential humeral loosening at a mean follow-up of 1.5 years (range: 1.5 months-3.4 years). Thirteen (7.1%) of these underwent revision shoulder arthroplasty where a loose stem was confirmed. All revisions underwent tissue culture, and 3 cases were consistent with probable or possible periprosthetic infection at the time of revision arthroplasty. The rate of symptomatic aseptic humeral loosening in this series was 10.9% (20/184), with 5.4% undergoing revision surgery. Patients with symptomatic aseptic humeral loosening were more likely to be male (90.5%) than those patients without symptoms (52.8%, P < .001). There were no differences in canal fit between patients with concern for symptomatic loosening and those with pain-free, stable implants. In this multisurgeon, multicenter study, the early humeral loosening rate for this stem design far outpaces previously reported rates, and this study likely under-reports the true incidence of clinically significant loosening as it only contains limited short-term follow-up. The perception that humeral loosening is nearly pathognomonic for periprosthetic shoulder infection should be reconsidered for certain short humeral stem designs.

Original Fixation Technique for Periprosthetic Humeral Fractures: Locking Plate for Lockable Stem

The prevalence of periprosthetic humeral fractures is 0.6% to 3%. These periprosthetic fractures are very challenging to treat because of the risk of complications and reduced function, especially when the humeral implant needs to be changed. The aim of this study was to evaluate the possibility of stabilizing the fracture without removing the existing humeral stem.

Stem retention and survival in revision of anatomical convertible shoulder arthroplasty to reverse arthroplasty: a Dutch registry study

BackgroundConvertible stem designs allow for stem retention during revision from anatomical to reverse shoulder arthroplasty. In some cases conversion is not possible for example due to excessive soft tissue tensioning. In these cases a total revision is necessary. The primary aim of this Dutch registry study was to evaluate the unforeseen stem reversion percentages in revision of convertible anatomical shoulder arthroplasty to reverse shoulder arthroplasty.MethodsShoulder arthroplasties (n = 2834) performed between 2014 and 2016 registered in the Dutch Arthroplasty Registry were selected. In 2016 94% of primary arthroplasties and 92% of revision arthroplasties were registered in the database. Arthroplasties were selected on convertibility. Mean follow-up was 2.4 years. We analysed the number of revisions for convertible and non-convertible designs. Cases with obligatory revisions as periprosthetic joint infections, stem loosening and periprosthetic fractures were excluded. Kaplan-Meier analysis was used to calculate humeral stem survival. Multivariate cox-regression analysis was used to determine risk factors for stem revision.ResultsThe majority of procedures (respectively 90.9 and 72.1% for the convertible and non-convertible group) concerned a conversion to reverse shoulder arthroplasty (p = .02). In the convertible group, the stem was retained in 29 out of 40 patients (72.5%). Overall implant survival was 94.5% after a mean follow-up of 2.4 years. Hemiartroplasty, fracture as primary indication, previous shoulder surgery and lower age were risk factors for revision.ConclusionsAlthough convertible designs are gaining popularity due to their expected advantage in revision arthroplasty, surgeons should be aware that during a revision procedure in 27.5% of the patients an unforeseen stem revision is necessary.

Clinical and radiological outcomes of reverse shoulder arthroplasty for acute fracture in the elderly.

The goal of this study was to assess the clinical outcomes associated with anatomic healing of the greater tuberosity in patients treated for proximal humerus fractures with reverse shoulder arthroplasty. Our hypothesis was that anatomic healing of the greater tuberosity leads to less complications and better functional outcomes. RESULTS: Patients from the GT+ group presented better functional outcomes than the GT- group in all evaluated outcomes. Mean constant score was 61 ± 14 versus 56 ±15, and the subjective shoulder value (SSV) was 77±14 versus 64± 21 (p< 0.001). Forward elevation was 128° ±28° versus 107°±30° and external rotation was 23°±17° versus 14°±17° (p < 0.001). Twenty patients presented with at least one prosthetic dislocation (7 GT+ vs 13 GT-) while nine patients were revised for humeral loosening (1 GT+ vs 8 GT-). The use of a fracture specific humeral stem was associated with a higher rate of greater tuberosity healing. Non-anatomic healing of the greater tuberosity was associated with a higher dislocation and humeral loosening rate. Anatomic healing of the greater tuberosity lead to better functional outcomes, less humeral-sided complications, and fewer re-operations.

Validation of new shoulder periprosthetic joint infection criteria

A periprosthetic joint infection (PJI) in the shoulder can be difficult to diagnose. Many variables have been used to determine a PJI. Recently, the 2018 International Consensus Meeting (ICM) on orthopedic infections gave new criteria to help identify PJI in the shoulder. With the new criteria (major and minor), the PJI definition can be categorized into definite, probable, possible, and unlikely. This study was conducted to assess the new criteria for a series of consecutive first stage revision shoulder arthroplasty cases. All patients undergoing a first stage revision shoulder arthroplasty using a prosthesis made of antibiotic-loaded acrylic cement (PROSTALAC) spacer from 2016 through 2019 were evaluated retrospectively. All cases were performed by a single surgeon. Each case was reviewed using the 2018 shoulder ICM diagnostic criteria. Secondary factors evaluated were type of organism identified, accuracy of minor criteria, and frozen vs. permanent section accuracy. A total of 87 first-stage revision arthroplasty cases were reviewed. Based on the 2018 ICM criteria, there were 20 definite (30.0%), 19 probable (21.8%), 6 possible (6.9%), and 42 unlikely (48.3%) infections. Cutibacterium acnes was the most common infectious organism overall (77.3% of culture positive cases) and was present in 39.1% of cases overall. Ten patients (25.6%) grew multiple organisms. Thirty-one patients (35.6%) had a loose humeral stem, with 23 of those patients (74.2%) having a definite or probable infection (odds ratio [OR] 7.2, 95% confidence interval [CI] 2.67-19.37, P = .0001). Eleven patients (91.7%) with an elevated intraoperative synovial neutrophil cell count had a definite or probable infection. Erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) was elevated in patients with a definite or probable infection (OR 9.4, 95% CI 2.47-35.62, P = .0010, and OR 7.7, 95% CI 2.29-25.56, P = .0009), respectively. Discordant results between frozen and permanent sections were found in 4 patients (4.6%). The 2018 ICM shoulder infection criteria gave a new scoring system to diagnose PJI. C acnes was the most common infectious organism identified. Patients who had a loose humeral stem, elevated ESR, or elevated CRP were more likely to have either a definite or probable PJI. Frozen sections were able to accurately identify definite infections. Unexpected wound drainage and positive preoperative cultures were low-yield criteria in this series. More research into determining periprosthetic shoulder infection is needed to help identify which patients are more likely to have an infection.

Humeral osteolysis after reverse shoulder arthroplasty using cemented or cementless stems comparative retrospective study with a mean follow-up of 9 years

IntroductionThe cause of proximal humeral osteolysis after reverse shoulder arthroplasty (RSA) remains controversial. The primary objective of our study was to compare the radiographic outcomes of Grammont-type RSA when a cemented stem is used versus when a cementless stem is used. The secondary objective was to identify the cause of these radiographic changes, especially for the cementless stems. HypothesisMore proximal humerus bone loss occurs when a cementless humeral stem is used. MethodsWith a minimum follow-up of 5 years, two paired cohorts were compared retrospectively: 70 RSA with cemented stem and 70 RSA with cementless stem. Using the radiographs made at the final follow-up visit, we looked for tuberosity resorption, signs of stress shielding, the presence of periprosthetic radiolucent lines and scapular notching. ResultsAt a mean follow-up of 9 years (5.0–20.6), the RSA revision rate was 1.8% in the cemented group and 3.6% in the cementless group (p=1). Tuberosity resorption was twice as common in the cementless group: 59% versus 30% (p<0.001). Signs of stress shielding such as osteopenia were only present in the cementless group. In both groups, tuberosity resorption was often associated with scapular notching. In the shoulders with tuberosity resorption, stage≥3 scapular notching was more common in the cementless group (p=0.001). DiscussionFor the cementless stems, proximal humeral osteolysis can in part be attributed to stress shielding. The relationship between notching and tuberosity resorption in the two groups also suggests a secondary biological cause. Level of evidenceIII; Comparative retrospective study.

Original Fixation Technique for Periprosthetic Humeral Fractures: Locking Plate for Lockable Stem

Introduction: The prevalence of periprosthetic humeral fractures is 0.6% to 3%. These periprosthetic fractures are very challenging to treat because of the risk of complications and reduced function, especially when the humeral implant needs to be changed. The aim of this study was to evaluate the possibility of stabilizing the fracture without removing the existing humeral stem. Materials and Methods: Five patients with a mean age of 82 years (69-99) were analyzed. These patients had suffered a periprosthetic humeral fracture. The shoulder arthroplasty implant was either anatomical or reversed with a locked humeral stem. The fractures (4 Worland type C and 1 type B2) occurred an average of 57.5 months (1-156) after the arthroplasty. Plate fixation was done in all cases through an anterior surgical approach; the screws associated with the plate were inserted through the plate and into the holes in the existing humeral stem. The functional outcomes (Constant score, Quick DASH) and radiological outcomes (bone union, displacement) were evaluated until the fracture healed. Results: Four patients were followed prospectively and the other was reviewed after a minimum follow-up of 1 year. There were no infections. One patient was lost to follow-up after 2 months. The mean surgery duration was 50 minutes (45-60). Four fractures healed within 3 months and one at 2 months. There were no intraoperative or postoperative complications. At a minimum follow-up of 6 months, the mean Constant score was 51 (32-60), the weighted Constant score was 79 (64-85) and the mean Quick DASH was 42 (18-38). All patients had regained the range of motion they had before the fracture. None of the patients required reoperation and all had returned to the same quality of life as before the fracture within 3 months. Conclusion: Analysis of these five cases shows the feasibility and simplicity of using the holes in the existing lockable humeral stem to stabilize a plate manufactured specifically for this type of stem. For periprosthetic fractures in patients who already have a lockable humeral stem, a stable construct can be achieved that firmly binds the diaphysis and implant. This type of construct allows the existing humeral stem to be preserved in cases of complex periprosthetic fractures in older adults and the operating time to be shortened.

The effect of humeral stem alignment in reverse shoulder arthroplasty

BackgroundThe impact of stem alignment on hip arthroplasty outcomes has been thoroughly evaluated, but there is limited data assessing this relationship in reverse shoulder arthroplasty (RSA). In this study, we investigated the association of humeral stem alignment with patient outcomes following RSA. MethodsUsing our prospectively maintained institutional registry, we identified patients who underwent reverse shoulder arthroplasty between July 2015 and September 2017 with minimum 2-year follow-up. Two raters independently assessed stem alignment using full-length humeral view radiographs. Stem alignment was correlated to American Shoulder and Elbow Surgeons (ASES) score, Visual Analog Scale (VAS) pain score, range of motion, complications, and scapular notching at 2-year follow-up. ResultsOf the 117 patients that fit our inclusion criteria, 68 (58%) had neutral or valgus alignment and 49 (42%) had varus alignment. ASES score, VAS pain score, range of motion, complications, and scapular notching showed no differences between the 2 cohorts at 2-years postoperatively. Change (mean, SD) in ASES scores (52.5 ± 17.7 vs. 41.3 ± 21.2, P = .01) and VAS pain scores (−5.7 ± 2.5 vs. −4.6 ± 2.6, P = .02) were greater in the neutral/valgus cohort compared to the varus cohort. Demographics analysis revealed that the neutral or valgus cohort had a larger female population (74% vs. 59%, P < .01) while men were more likely to be in the varus cohort. ConclusionHumeral stem alignment does not appear to affect clinical outcomes at 2-years postoperatively. Improvement in ASES score and VAS pain score were slightly inferior in varus patients, however this difference was not clinically relevant. There may be a correlation between male gender and varus alignment, likely due to better bone quality and larger musculature. Further investigation into the association between stem angulation and clinical outcomes is warranted. Levels of EvidenceLevel III; Retrospective Cohort Study.

Clinical and radiographic outcomes of cementless reverse total shoulder arthroplasty for proximal humeral fractures.

Reverse total shoulder arthroplasty (RTSA) has demonstrated successful outcomes in the treatment of both acute and chronic proximal humeral fractures (PHFs). The traditional RTSA surgical technique uses a methyl methacrylate cemented humeral component to restore and maintain both humeral height and retroversion. However, use of humeral bone cement has been associated intraoperatively with cardiopulmonary risk, increased operative cost, and postoperatively with difficulty if revision arthroplasty is required. We report the clinical and radiographic outcomes of a completely cementless RTSA technique for PHF surgery. Between 2013 and 2018, 60 consecutive patients underwent surgical management of a PHF with cementless RTSA. All surgical procedures were performed by a single senior shoulder surgeon using a modified deltopectoral approach and a completely uncemented RTSA technique. Fractures were defined as either acute or chronic based on a 4-week injury-to-surgery benchmark. The mean age was 67 years (range, 47-85 years). There were 18 acute and 42 chronic fractures. The mean time from injury to surgery was 2 weeks (range, 0.4-4 weeks) for acute fractures and 60 months (range, 1-482 months) for chronic fractures. We excluded 17 cases from postoperative evaluation because of revision and/or loss to follow-up. The remaining 43 cases underwent clinical and radiographic evaluation by 2 independent fellowship-trained shoulder surgeons at a mean of 21 months (range, 10-46 months) postoperatively. Independent statistical analysis was performed using the paired t test and Wilcoxon signed rank test. At final review, mean active anterior elevation was 157° (range, 100°-170°); active external rotation, 52° (range, 6°-80°); and active internal rotation, 66° (range, 0°-80°). Improvements were seen in the visual analog scale pain score (from 6 to 0.2, P < .001), Simple Shoulder Test score (from 9 to 93, P < .001), American Shoulder and Elbow Surgeons score (from 19 to 91, P < .001), and Single Assessment Numeric Evaluation score (from 21% to 89%, P < .001). Overall, 39 of 43 greater tuberosities (91%) demonstrated osseous healing to the humeral shaft. No significant differences in clinical and radiographic outcomes were found in acute vs. chronic cases, as well as cases with minimum follow-up of 1 year vs. 2 years. Overall, there were 4 major complications necessitating surgical revision (6.7%) and no cases of aseptic humeral stem loosening. Cementless RTSA for acute and chronic PHFs demonstrates clinical and radiographic outcomes similar to those after traditional cemented RTSA. The successful greater tuberosity healing and absence of humeral stem loosening in this short-term cohort are encouraging for the continued long-term success of this technique. By avoiding cemented humeral implants, surgeons may minimize intraoperative complications, operative cost, and postoperative revision difficulty.

Revision to reverse total shoulder arthroplasty: do short stem and stemless implants reduce the operative burden compared to convertible stems?

BackgroundRevision of prior hemiarthroplasty (HA) or total shoulder arthroplasty (TSA) to reverse shoulder arthroplasty (RSA) is a technically challenging procedure with high complication rates. The purpose of this study was to compare intraoperative complications between convertible humeral stems and nonconvertible humeral stems stratified by stem length for conversion of TSA or HA to RSA. Materials and methodsA multicenter retrospective analysis of patients undergoing revision of a primary TSA or HA to RSA was conducted. Patients were divided into 2 groups based on convertible or nonconvertible humeral stem design from the index surgery. The primary outcome measures were the following intraoperative variables and complications: total operative time, blood loss, intraoperative fracture, overall complication rate, and blood transfusions. Rates were compared between groups and analyzed according to primary stem length for the nonconvertible group. ResultsA total of 279 patients were included in the study, 70 with convertible stems and 209 with nonconvertible stems. About 70% of convertible stems were successfully retained. Operative time was similar between the 2 groups overall. Patients with nonconvertible stems had higher intraoperative blood loss (P = .0001), higher overall complication rate (P = .009), and greater risk of intraoperative fracture (P= .002). Revising stemless and short stems to RSA had significantly reduced operative time compared to standard length stems (97 and 116 minutes vs. 141 minutes, P < .0001 and P = .035, respectively). When revising stemless implants, there was a significantly lower rate of intraoperative fracture (3.6%) compared to short stems (24%, P = .004) and standard stems (23.4%, P = .001). When revising stemless implants to RSA, there was shorter operative time (P= .0001) and similarly low rate of intraoperative fracture (P= .820) compared to convertible stems. ConclusionIn revision of anatomic TSA to RSA, convertible stems lead to lower blood loss and intraoperative fracture rate compared to nonconvertible stems when broadly including all stem types. However, differences appear to be based on stem type. Among nonconvertible stems, revision of short stem and stemless implants are associated with reduced operative time compared to standard length stems. Revision of stemless implants to RSA is associated with the shortest operative time of all implant types as well as a similar rate of intraoperative fracture compared to convertible stems. Level of EvidenceLevel III; Retrospective Cohort Comparative Study

Creation of a Custom-Length, Humeral Antibiotic Cement Spacer for Use in Treatment of Shoulder Periprosthetic Joint Infection

Periprosthetic joint infection of the shoulder is a challenging clinical situation to manage owing to the fastidious organisms often present and delayed clinical presentation. While several treatment options have been described, the mainstay of treatment remains a staged revision with the use of a humeral antibiotic cement spacer. Such spacers are commercially available or can be made by hand. When an extended humeral osteotomy is required to remove a well-fixed long stem humeral component, it may be advantageous to place an antibiotic spacer with a stem length approximately as long as the hardware being removed. This technique demonstrates creation of a custom length, humeral antibiotic cement spacer for use in treatment of shoulder periprosthetic joint infection.

The Lesser Tuberosity Osteotomy Exposure for Total Shoulder Arthroplasty.

The lesser tuberosity osteotomy (LTO) is a commonly employed technique for mobilizing the subscapularis tendon during anatomic total shoulder arthroplasty that is performed through a deltopectoral approach. During this procedure, the lesser tuberosity is osteotomized from the proximal aspect of the humerus while maintaining the strong tendon-to-bone attachment of the subscapularis tendon insertion. After the shoulder arthroplasty is performed, the lesser tuberosity osseous fragment is then resecured to the proximal aspect of the humerus with heavy nonabsorbable suture, which allows for direct bone-to-bone compression and healing of the fragment to the proximal aspect of the humerus. This technique may be utilized for subscapularis tendon mobilization in any primary and some revision anatomic total shoulder arthroplasty procedures. The procedure is performed as follows. (1) Preoperative planning is performed. (2) The patient is positioned in the semi-upright beach-chair position, and the shoulder girdle and the upper arm are prepared and draped. (3) A standard deltopectoral approach is utilized. (4) A tenotomy of the long head of the biceps tendon is performed, exposing the bicipital groove. (5) An LTO is made from lateral to medial with an oscillating saw and is completed with use of an osteotome. (6) The remaining inferior portion of the subscapularis and capsule are released off of the humerus. (7) The total shoulder arthroplasty is completed up to the point of implantation of the final humeral component. (8) Four drill-holes are made lateral to the bicipital groove and osteotomy site. (9) Heavy nonabsorbable sutures, with or without cerclage wires, are passed from lateral to medial around the humeral stem and passed medial to the osteotomy fragment through the insertion of the subscapularis tendon. (10) The sutures are then tensioned and tied with the arm in 30° of external rotation. (11) The wound is irrigated, dried, and closed in layered fashion. The most commonly accepted alternative approaches include the subscapularis tenotomy and subscapularis peel techniques. The LTO approach technique was developed to take advantage of bone-to-bone healing and to address concerns regarding poor tendon-to-tendon or tendon-to-bone healing in the subscapularis tenotomy and subscapularis peel exposure techniques, respectively. Based on numerous published studies, excellent clinical results are achieved with anatomic total shoulder arthroplasty. When comparing surgical techniques involving the subscapularis in Level-I, randomized controlled trials, no significant differences exist among clinical outcomes, range of motion, or strength between the different techniques. Three-dimensional preoperative templating software allows for the anticipation of potential operative challenges, the prediction of implant limitations, and more accurate assessment of abnormal glenoid morphology and wear patterns.An articulating arm positioner can be helpful in controlling the arm position without the need for an extra surgical assistant.The goal thickness of the LTO is 10 mm. If the osteotomy is made too thin, there is a risk that the repair sutures cut through the lesser tuberosity fragment, leading to subscapularis repair failure.Releasing the capsule from the subscapularis is a critical step to ensure adequate tendon excursion for later repair and restoration of external rotation in arthritic shoulders. However, careful attention must be directed to the position and orientation of the axillary nerve in order to avoid iatrogenic injury during this critical step.Creating the drill-holes lateral to the bicipital groove takes advantage of the very strong and dense bone in that area of the proximal aspect of the humerus, enhancing the integrity of the repair.The tension band suture is critical to aid in further compression of the LTO fragment when the arm is brought into external rotation.Closing the rotator interval substantially increases the strength of the subscapularis repair; however, the closure of the interval must be made with the arm in at least 30° of external rotation in order to avoid iatrogenic motion restriction.Using interrupted nonabsorbable sutures to close the deltopectoral interval at the conclusion of the procedure is helpful in the event that any revision procedure is needed because these sutures will guide the revision surgeon toward making the deltopectoral approach in the correct interval. LTO = lesser tuberosity osteotomyROM = range of motionASES = American Shoulder and Elbow SurgeonsWOOS = Western Ontario Osteoarthritis of the Shoulder indexVAS = visual analog scaleSF-36 = 36-Item Short Form Health SurveySST = Simple Shoulder TestDVT = deep-vein thrombosis.

Conversion to Reverse Total Shoulder Arthroplasty With and Without Humeral Stem Retention

Conversion to Reverse Total Shoulder Arthroplasty With and Without Humeral Stem Retention

Onlay versus inlay reverse total shoulder arthroplasty: a retrospective comparison of radiographic and clinical outcomes

IntroductionRecent innovations in reverse shoulder arthroplasty (RSA) have presented 2 distinct humeral stem designs: an onlay system that rests above the anatomic neck and an inlay component that rests within the metaphysis. The purpose of this study is to compare clinical and radiographic outcomes between inlay and onlay-designed humeral stems in lateral center of rotation RSA implant systems. MethodsA retrospective cohort study was performed on primary RSA patients treated by 2 surgeons at 2 separate hospitals with a minimum 2-year follow-up. Patients were categorized based on treatment with an onlay or inlay humeral design and matched 1:1 by indication and age. Patient-reported outcome measures (PROMs), including the Simple Shoulder Test, American Shoulder and Elbow Surgeons, and Visual Analog Score for pain, as well as active motion (forward elevation, internal rotation) were recorded at pre- and postoperative intervals. An Inlay-Onlay index assessed the degree of inset or offset of each particular implant referencing the anatomic neck. Radiographic analysis focused on scapular notching, bone resorption around the humeral stem, and acromion stress fractures. ResultsA total of 92 patients participated in the 1:1 matched analysis (46 each group). Cohorts were similar in age, gender, indication, follow-up length, and preoperative PROMs, with the exception of Simple Shoulder Test. At the most recent follow-up, there were no differences in all PROMs between groups. There were no differences in active internal rotation, but patients with an onlay-configuration demonstrated greater external rotation (P< .001) and forward flexion (P< .001). Greater tuberosity and calcar resorption occurred in 34 (74%) and 18 (39%) patients with an onlay-designed prosthesis, compared to 13 (28%) and 1 (2%) in the inlay group, respectively (P< .0001). Both groups had low rates of scapular notching (P= 1.0), while acromial fractures occurred in 6 patients with an onlay stem and in 4 patients with the inlay stem (P= .73). ConclusionThere were no differences in clinical outcomes or incidence of acromial fractures following RSA with an onlay- or inlay-style humeral stem prosthesis. Bone resorption of the proximal humerus occurred more frequently in patients with an onlay prosthesis, suggesting that an inlay prosthesis may afford better prevention of humeral stress shielding. Level Of EvidenceLevel III; Retrospective Comparative Study

Midterm clinical outcomes of reverse shoulder arthroplasty in Japanese patients with rheumatoid arthritis using patient-reported outcome measures (Shoulder36).

BackgroundReverse shoulder arthroplasty normally has adequate functional outcomes in patients with cuff tear arthropathy. The present study aimed to investigate the midterm clinical outcomes of reverse shoulder arthroplasty in Japanese patients with rheumatoid arthritis.MethodsBetween July 2014 and May 2016, reverse shoulder arthroplasty was performed in 14 rheumatic shoulders with joint destruction and rotator cuff tears. The range of motion, Constant score, and Shoulder36, which is a patient-reported outcome measure, were compared preoperatively and postoperatively. The prevalence of subscapular notching, subscapular osteophytes, postoperative fractures, and stress shielding of the humeral stem were evaluated by X-ray.ResultsRange of motion significantly improved from 77 to 122 degrees in flexion and from 67 to 111 degrees in abduction at four years. The Constant score significantly improved from 27 to 62, and each domain of Shoulder36 also significantly increased at four years. There was no dislocation, infection, or loosening of the prosthesis. Three shoulders presented scapular notching, and three cemented humeral stems showed stress shielding in the proximal humeral cortical bone.ConclusionReverse shoulder arthroplasty performed in Japanese patients with rheumatoid arthritis not only decreased the pain and improved the function of the shoulder joint but also significantly improved patients’ health and activity of daily living in midterm results.

The effect of stem length on reverse total shoulder humeral fixation

BackgroundThe purpose of this study was to evaluate the relative contribution of the reverse shoulder arthroplasty (RSA) humeral stem length on initial implant fixation, which may contribute to the long-term success of uncemented shoulder implants. MethodsThree RSA humeral components were randomly divided into the following testing groups: (1) 100% Stem length (n = 7); (2) 50% Stem length (n = 7); (3) 0% Stem length (n = 7). Each humeral stem was press-fit into twenty-one 4th Generation Osteoporotic Sawbones humeri. Torque and compressive axial load were applied to the humerus for 10,000 cycles at ±2.5 Nm and −392 N, respectively. Rotational micromotion of the implant was measured. ResultsMicromotion for all 3 testing groups was below the 150 µm micromotion threshold throughout testing. The overall micromotion in Group 2 was significantly larger than Group 1 (P < .001) and Group 3 (P < .001). Overall micromotion between Group 1 and Group 3 were not significantly different (P = .686). ConclusionAll stem lengths studied maintained micromotion below the 150 µm threshold, suggesting that any of these treatment groups would provide adequate initial fixation to allow bony on-growth. Clinically, stemless or short-stemmed prosthesis design offer theoretical benefits such as the degree of freedom for humeral stem placement independent of diaphysis. This study concluded that the zero-length stem will allow for this and provide adequate fixation comparable to the full-length stem. Level of EvidenceBasic Science Study.

Referencing the pectoralis major tendon for humeral stem height placement in reverse shoulder arthroplasty for fracture

BackgroundProximal humerus fractures remain a challenging problem, and reverse total shoulder arthroplasty (RSA) has demonstrated reliable outcomes in fracture applications. Despite this, guidelines for placement of the humeral component are lacking. MethodsTwelve cadaveric shoulders (6 cadaveric torsos) were utilized. An onlay RSA stem was placed with the lateral potion of the humeral cup positioned at the level of the greater tuberosity. Measurements were taken from the top of the pectoralis major tendon to the top of the humeral stem. A separate computer-aided analysis was conducted analyzing the height of an RSA humeral stem and an RSA humeral stem with a cup using values extrapolated from prior data. ResultsThe average distance from the top of the pectoralis to the top of the humeral stem was 4.0 cm (3.4 cm to 4.8 cm) with a standard deviation of 4.1. The humeral cup added an average of 9.1 mm. Computer-aided design data demonstrated the average height of the humeral stem was 3.9 cm above the superior aspect of the pectoralis tendon, and the average height with the humeral cup added was 4.8 cm. ConclusionBoth the cadaveric and computer-aided design data demonstrated a similar height for both the distances from the superior portion of the pectoralis to the superior aspect of an onlay RSA stem and the humeral cup. The measurement from the humeral cup may allow for translational use with inlay RSA humeral stems. This study demonstrates the superior border of the pectoralis major tendon to be a reliable landmark in RSA humeral stem placement. Level of evidenceLevel IV; Cadaveric Study