The role of serum C-reactive protein in the diagnosis of periprosthetic shoulder infection.

INTRODUCTION: There is a paucity of literature regarding serum C-reactive protein (CRP) in the evaluation of a shoulder periprosthetic joint infection (PJI). The purpose of the current study was to establish cutoff values for diagnosing shoulder PJI and evaluate the influence of the type of infecting microorganism and the classification subgroups according to last proposed International Consensus Meeting (ICM) criteria on the CRP level. MATERIALS AND METHODS: A retrospective analysis of all 136 patients, who underwent septic or aseptic revision shoulder arthroplasty in our institution between January 2010 and December 2019, was performed. Shoulder PJI was defined according to the last proposed definition criteria of the ICM. Serum CRP levels were compared between infected and non-infected cases, between infection subgroups, as well as between different species of infecting microorganisms. A receiver-operating characteristic (ROC) analysis was performed to display sensitivity and specificity of serum CRP level for shoulder PJI. RESULTS: A total of 52 patients (38%) were classified as infected, 18 meeting the criteria for definitive infection, 26 for probable infection and 8 for possible infection. According to the ROC curve, an optimized serum CRP threshold of 7.2 mg/l had a sensitivity of 69% and specificity of 74% (area under curve = 0.72). Patients with definitive infection group demonstrated significantly higher median serum CRP levels (24.3 mg/l), when compared to probable, possible infection groups and PJI unlikely group (8 mg/l, 8.3 mg/l, 3.6 mg/l, respectively, p < 0.05). The most common isolated microorganism was Cutibacterium acnes in 25 patients (48%) followed by coagulase-negative staphylococci (CNS) in 20 patients (39%). Patients with a PJI caused by high-virulent microorganisms had a significantly higher median serum CRP level compared to patients with PJI caused by low-virulent microorganisms (48 mg/l vs. 11.3 mg/l, p = 0.04). CONCLUSIONS: Serum CRP showed a low sensitivity and specificity for the diagnosis of shoulder PJI, even applying cutoffs optimized by receiver-operating curve analysis. Low-virulent microorganisms and patients with probable and possible infections are associated with lower CRP levels compared to patients with definitive infection and infections caused by high-virulent microorganisms. LEVEL OF EVIDENCE: Diagnostic Level III.

Glenoid vault and humeral head alignment in relation to the scapular blade axis in young patients with pre-osteoarthritic static posterior subluxation of the humeral head.

BACKGROUND: Static posterior subluxation of the humeral head is a pre-osteoarthritic deformity preceding posterior erosion in young patients. Its etiology remains unknown. The aim of this study was to analyze the differences in scapular morphology between young patients with pre-osteoarthritic static posterior subluxation of the humeral head and healthy controls with a centered humeral head. METHODS: We performed a retrospective analysis of all patients with pre-osteoarthritic static posterior subluxation of the humeral head who were treated in our institution between January 2018 and November 2019. Fourteen shoulders in 12 patients were included in this study and then matched according their age, sex, and affected side with controls. Computed tomography images of both groups were compared in the standardized axial imaging plane for differences in scapular morphology. The following parameters were measured: glenoid version relative to the Friedman line and scapular blade axis, scapulohumeral and glenohumeral subluxation index, and neck angle, as well as glenoid and humeral offset. RESULTS: The patients in the subluxation group showed significantly higher scapulohumeral and glenohumeral subluxation indexes than controls (0.76 vs. 0.55 [P < .0001] and 0.58 vs. 0.51 [P = .016], respectively). The mean measurements of glenoid version according to the Friedman line and relative to the scapular blade axis were significantly higher in the subluxation group than in controls (19° vs. 4° [P < .0001]and 14° vs. 2° [P = .0002], respectively). The glenoid vault was significantly more anteriorly positioned with respect to the scapular blade axis in the subluxation group than in controls (neck angle, 166° vs. 173° [P = .0003]; glenoid offset, 9.2 mm vs. 4.6 mm [P = .0005]). The midpoint of the humeral head showed a posterior offset with respect to the scapular blade axis in the subluxation group, whereas controls had an anteriorly placed midpoint of the humeral head (-2 mm vs. 3.1 mm, P = .01). A higher scapulohumeral subluxation index showed significant correlations with an increased anterior offset of the glenoid vault (increased glenoid offset: r = 0.493, P = .008 and decreased neck angle: r = -0.554, P = .002), a posterior humeral offset (r = -0.775, P < .0001), and excessive glenoid retroversion measured by both methods (Friedman line: r = 0.852, P < .0001; scapular blade axis: r = 0.803, P < .0001). A higher glenohumeral subluxation index also correlated significantly with an increased anterior offset of the glenoid vault (increased glenoid offset: r = 0.403, P = .034; decreased neck angle: r = -0.406, P = .032) and posterior humeral offset (r = -0.502, P = .006). CONCLUSION: Young patients with pre-osteoarthritic static posterior subluxation of the humeral head have significant constitutional differences in scapular morphology in terms of an increased anterior glenoid offset, excessive glenoid retroversion, and increased posterior humeral offset in relation to the scapular blade compared with healthy matched controls.

Characteristics of functional shoulder instability.

BACKGROUND: Pathologic activation pattern of muscles can cause shoulder instability. We propose to call this pathology functional shoulder instability (FSI). The purpose of this prospective study was to provide an in-detail description of the characteristics of FSI. METHODS: In the year 2017, a total of 36 consecutive cases of FSI presenting to our outpatient clinic were prospectively collected. Diagnostic investigation included a pathology-specific questionnaire, standardized clinical scores, clinical examination, psychological evaluation, video and dynamic fluoroscopy documentation of the instability mechanism, as well as magnetic resonance imaging (MRI). In a final reviewing process, the material from all collected cases was evaluated and, according to the observed pattern, different subtypes of FSI were determined and compared. RESULTS: Based on the pathomechanism, positional FSI (78%) was distinguished from nonpositional FSI (22%). Controllable positional FSI was observed in 6% of all cases and noncontrollable positional FSI in 72%, whereas controllable and noncontrollable nonpositional FSI were each detected in 11% of the cases. The different subtypes of FSI showed significant differences in all clinical scores (Western Ontario Shoulder Instability Index: P = .002, Rowe Score: P = .001, Subjective Shoulder Value: P = .001) and regarding functional impairment (shoulder stability: P < .001, daily activities: P = .001, sports activities: P < .001). Seventy-eight percent had posterior, 17% anterior, and 6% multidirectional instability. Although several patients showed constitutional glenoid shape alterations or soft tissue hyperlaxity, only few patients with acquired minor structural defects were observed. CONCLUSION: FSI can be classified into 4 subtypes based on pathomechanism and volitional control. Depending on the subtype, patients show different degrees of functional impairment. The majority of patients suffer from unidirectional posterior FSI.

Epidemiology of functional shoulder instability: an online survey.

BACKGROUND: Functional shoulder instability (FSI) is defined as glenohumeral instability that is not caused by structural defects but rather by abnormal muscle activation patterns. Patients with FSI are able to dislocate their shoulder at will, either by motion (positional FSI) or even without moving the arm (non-positional FSI). In contrast to structural shoulder instability, little is known about the epidemiology of FSI. The aim of the following study was to further analyse this rare pathology and approximate the prevalence of FSI. METHODS: A self-evaluated and anonymous online survey among 5866 medical students was conducted using the students email list of two german-speaking medical universities (Study Center 1 and Study Center 2). Possibly affected siblings were used as a supplementary group (Siblings Cohort). General sociodemographic data, dislocation mechanism, potential causes, age at the tie of developing first symptoms, general hyperlaxity, previous interventions, and sporting activity were evaluated and analyzed. The total number of email recipients and responses was used to estimate the minimal and maximal prevalence of FSI. RESULTS: Five hundred thirteen questionnaires were completed by the students and subsequently analyzed. In total, there were 32 participants with FSI. The minimal prevalence of FSI was found to be 0,5% and the maximal prevalence 2,6%. In most cases (67%) a positional FSI was reported. The majority of the patients reported that first symptoms developed under the age of 16 years (69%) and without any traumatic event (72%). Most of the affected participants had no therapeutic intervention for their FSI (69%) and performed non-overhead (59%) or overhead sports (28%). CONCLUSION: Functional shoulder instability (FSI) is more common than expected amongst young adults and seems to develop during childhood mostly without specific reason.

Clinical prospective intra-individual comparison after mix-and-match implantation of a monofocal EDOF and a diffractive trifocal IOL.

OBJECTIVES: To assess intra-individually visual acuity (VA) and subjective outcome after mix-and-match implantation of a monofocal EDOF IOL and a diffractive trifocal IOL. METHODS: The monofocal EDOF Isopure IOL was implanted in the dominant eye and the trifocal FineVision HP IOL in the non-dominant eye. Postoperative evaluation included VA at various distances, contrast acuity, monocular defocus curves, decentration and tilt, wavefront aberrometry, VF-7 questionnaire and a halo and glare simulator. RESULTS: 50 eyes of 25 subjects were enroled. The trifocal IOL performed better at monocular DCNVA (p < 0.01) and at defocus levels of -1.5D to -4.0D (p < 0.01), the monofocal EDOF IOL was better at -0.5D (p = 0.013). No differences in monocular BCDVA, DCIVA, contrast acuity, decentration or tilt were observed (p > 0.05). Wavefront analysis revealed lower HOAs in the trifocal group at 5 mm (p < 0.01) and no difference (p = 0.107) at 3 mm pupil aperture. The monofocal EDOF IOL displayed increased negative SA at 5 mm (p < 0.01) and 3 mm (p < 0.01) pupil diameter. Low values of optical phenomena and satisfying results of the VF-7 questionnaire were obtained. CONCLUSION: Excellent visual performance and low rates of optical phenomena were achieved after mix-and-match implantation of the monofocal EDOF Isopure IOL and the trifocal FineVision HP IOL. Trifocal IOL implantation in the non-dominant eye may decrease optical disturbing phenomena. Similar results were observed for monocular distance, intermediate and contrast VA. The trifocal IOL provided better monocular near VA. Decentration and tilt and HOAs were low.

Intraindividual Comparison of an Enhanced Monofocal and an Aspheric Monofocal Intraocular Lens of the Same Platform.

PURPOSE: To compare intraindividual differences in visual performance of a monofocal and enhanced monofocal intraocular lens (IOL) of the same platform. DESIGN: Prospective, interventional, fellow-eye comparison clinical study. METHODS: In total, 55 patients (110 eyes) with bilateral age-related cataract were enrolled. All patients received a monofocal ZCB00 IOL in the dominant and an enhanced monofocal Eyhance ICB00 IOL in the nondominant eye. After 2 to 4 months, monocular best-corrected distant visual acuity (BCDVA), distance-corrected intermediate visual acuity (DCIVA), distance-corrected near visual acuity (DCNVA), contrast visual acuity, monocular defocus curves, internal higher-order aberrations (HOAs) and spherical aberrations (SA), decentration, and tilt were compared. RESULTS: The monocular mean BCDVA, DCIVA at 80 cm and 66 cm, and DCNVA were -0.03 ± 0.07, 0.24 ± 0.12, 0.32 ± 0.13, and 0.50 ± 0.13 logarithm of the minimum angle of resolution for the enhanced ICB00 and -0.06 ± 0.06 (P = .014), 0.30 ± 0.11 (P = .005), 0.38 ± 0.12 (P = .004), and 0.55 ± 0.14 (P = .034) logarithm of the minimum angle of resolution for the ZCB00, respectively. Internal HOAs (P = .001) and negative SA (P < .001) were increased with the ICB00 at 3 mm and comparable at 5 mm (P > .05). Contrast acuity, tilt, and decentration were similar (P > .05). CONCLUSIONS: Significantly increased monocular DCIVA at 80 cm and 66 cm and DCNVA at 40 cm were observed with the enhanced ICB00 IOL, and the ZCB00 IOL demonstrated better BCDVA. This would result in a mean gain of 2 to 3 Early Treatment of Diabetic Retinopathy Study letters at near and intermediate distance. Monocular defocus curves displayed highest differences of 5 Early Treatment of Diabetic Retinopathy Study letters at -1.25 diopters (D) and -1.50 D levels of defocus and a depth of focus of 1.23 D for the ICB00 IOL and 0.94 D for the ZCB00 IOL. Decentration, tilt, and HOAs were generally low.

Fellow-Eye Comparison Of Monocular Visual Outcomes Following Monofocal EDOF And Trifocal EDOF IOL Implantation.

PURPOSE: To compare intraindividual monocular visual performance of a monofocal EDOF and a trifocal EDOF IOL following bilateral cataract surgery. DESIGN: Single-center, prospective, fellow-eye comparison clinical trial. METHODS: All patients received uneventful bilateral cataract surgery with implantation of the monofocal EDOF Isopure IOL in the dominant eye and the trifocal EDOF FineVision Triumf IOL in the non-dominant eye. Intraindividual monocular comparison included visual acuity at various distances, defocus curves, internal total higher-order aberration (HOA), spherical aberration (SA) Z(4.0), IOL decentration and tilt. Additionally, subjective outcomes were evaluated using Halo and Glare simulation and the VF-7 questionnaire. RESULTS: In total, 25 patients (50 eyes) were included. Intraindividual monocular BCDVA, DCIVA, and BCNVA were comparable (p> .05). However, monocular contrast acuity (p= .019), DCNVA (p< .001) and defocus curves at defocus levels of 0.0D (p= .005) and between -1.5 and -4.0D (p< .001) differed significantly. At 5mm, internal HOA and SA Z(4.0) were significantly different (p< .001) and comparable at 3mm pupil diameter, as were IOL tilt and decentration (p> .05). CONCLUSION: In this combined fellow-eye comparison, near vision was significantly better with the trifocal EDOF IOL. The monofocal EDOF IOL demonstrated similar distance and intermediate visual performance as the trifocal EDOF IOL. Overall, low values of photic phenomena and visual impairment was observed.

Rotational stability and refractive outcomes of a new hydrophobic acrylic toric intraocular lens.

PURPOSE: To assess rotational stability and refractive outcomes of a new toric hydrophobic acrylic intraocular lens (IOL). DESIGN: Single-center, prospective, interventional clinical trial. METHODS: A total of 130 eyes of 82 patients with age-related cataract and total corneal astigmatism of greater than 1.0 diopters (D) received a hydrophobic acrylic toric IOL Clareon CNW0T3-9. Baseline measurement for rotational stability evaluation was performed at the end of surgery (EOS), with the patient still supine on the operating table, using non-movable vessels as reference landmarks. Postoperative retroillumination pictures were taken at 1 h, 1 week, 1 month and 4-6 months postoperatively. Subjective manifest refraction was assessed at the 6 months follow-up visit. RESULTS: Final results were obtained in 126 eyes of 80 patients. Mean absolute rotation from EOS to 6 months was 1.33 ± 2.00 [0.01, 19.80] degrees. Rotational stability values from EOS to 1 h, 1 h to 1 week, 1 week to 1 month and 1 month to 6 months were 0.86 ± 0.82 [0.00, 3.90], 1.06 ± 1.94 [0.00, 19.45], 0.47 ± 0.42 [0.00, 2.03] and 0.38 ± 0.40 [0.00, 2.56] degrees. Mean preoperative corneal astigmatism was 1.78 ± 0.83 [1.00, 4.76] D which changed to a mean postoperative refractive astigmatism of 0.33 ± 0.27 [0.00, 1.25] D at 6 months. CONCLUSION: The Clareon toric IOL presented very good rotational stability with a mean absolute rotation below 1.4° from EOS to 6 months. Only two IOLs rotated more than 5° with none of them requiring repositioning surgery. Refractive outcomes were satisfying with a mean residual refractive astigmatism below 0.50 D. TRIAL REGISTRATION: Registered at Clinicaltrials.gov NCT03803852 ; on May 17, 2022.

Neuromuscular Electrical Stimulation-Enhanced Physical Therapist Intervention for Functional Posterior Shoulder Instability (Type B1): A Multicenter Randomized Controlled Trial.

OBJECTIVE: Functional posterior shoulder instability (FPSI) (type B1) is a severe type of instability, mainly in teenagers and young adults, that leads to loss of function, pain, and stigmatization among peers. An experimental nonsurgical treatment protocol based on neuromuscular electrical stimulation (NMES) showed very promising early results in the treatment of FPSI. The hypothesis of this study was that NMES-enhanced physical therapy leads to better outcomes than physical therapy alone as the current gold standard of treatment in patients with FPSI. METHODS: In this multicenter randomized controlled trial, patients with FPSI were randomly allocated in a 1:1 ratio to either 6 weeks of physical therapy or 6 weeks of physical therapy with simultaneous motion-triggered NMES. Baseline scores as well as outcome scores at 6 weeks, 3 months, 6 months, and 12 months after the intervention were obtained. The predefined primary outcome of this trial was the Western Ontario Shoulder Instability Index (WOSI) at the 3-month time point. RESULTS: Forty-nine patients were randomized and eligible for the trial. The group that received physical therapy with simultaneous motion-triggered NMES showed a significantly better main outcome measurement in terms of the 3-month WOSI score (64% [SD = 16%] vs 51% [SD = 24%]). Two-thirds of the patients from the physical therapist group crossed over to the group that received physical therapy with simultaneous motion-triggered NMES due to dissatisfaction after the 3-month follow-up and showed a significant increase in their WOSI score from 49% [SD = 8%] to 67% [SD = 24%]. The frequency of instability episodes showed a significant improvement in the group that received physical therapy with simultaneous motion-triggered NMES at the 3-month follow-up and beyond, while in the physical therapist group, no significant difference was observed. CONCLUSION: The current study shows that NMES-enhanced physical therapy led to statistically significant and clinically relevant improvement in outcomes in the treatment of FPSI compared to conventional physical therapy alone-from which even patients with prior unsatisfactory results after conventional physical therapy can benefit. IMPACT: Based on the results of this study, NMES-enhanced physical therapy is an effective new treatment option for FPSI, a severe type of shoulder instability. NMES-enhanced physical therapy should be preferred over conventional physical therapy for the treatment of patients with FPSI.

Functional and Radiologic Outcomes of Degenerative Versus Traumatic Full-Thickness Rotator Cuff Tears Involving the Supraspinatus Tendon.

BACKGROUND: Arthroscopic rotator cuff repair (ARCR) is among the most commonly performed orthopaedic procedures. Several factors-including age, sex, and tear severity-have been identified as predictors for outcome after repair. The influence of the tear etiology on functional and structural outcome remains controversial. PURPOSE: To investigate the influence of tear etiology (degenerative vs traumatic) on functional and structural outcomes in patients with supraspinatus tendon tears. STUDY DESIGN: Cohort study; Level of evidence, 2. METHODS: Patients undergoing ARCR from 19 centers were prospectively enrolled between June 2020 and November 2021. Full-thickness, nonmassive tears involving the supraspinatus tendon were included. Tears were classified as degenerative (chronic shoulder pain, no history of trauma) or traumatic (acute, traumatic onset, no previous shoulder pain). Range of motion, strength, the Subjective Shoulder Value, the Oxford Shoulder Score (OSS), and the Constant-Murley Score (CMS) were assessed before (baseline) and 6 and 12 months after ARCR. The Subjective Shoulder Value and the OSS were also determined at the 24-month follow-up. Repair integrity after 12 months was documented, as well as additional surgeries up to the 24-month follow-up. Tear groups were compared using mixed models adjusted for potential confounding effects. RESULTS: From a cohort of 973 consecutive patients, 421 patients (degenerative tear, n = 230; traumatic tear, n = 191) met the inclusion criteria. The traumatic tear group had lower mean baseline OSS and CMS scores but significantly greater score changes 12 months after ARCR (OSS, 18 [SD, 8]; CMS, 34 [SD,18] vs degenerative: OSS, 15 [SD, 8]; CMS, 22 [SD, 15]) (P < .001) and significantly higher 12-month overall scores (OSS, 44 [SD, 5]; CMS, 79 [SD, 9] vs degenerative: OSS, 42 [SD, 7]; CMS, 76 [SD, 12]) (P≤ .006). At the 24-month follow-up, neither the OSS (degenerative, 44 [SD, 6]; traumatic, 45 [SD, 6]; P = .346) nor the rates of repair failure (degenerative, 14 [6.1%]; traumatic 12 [6.3%]; P = .934) and additional surgeries (7 [3%]; 7 [3.7%]; P = .723) differed between groups. CONCLUSION: Patients with degenerative and traumatic full-thickness supraspinatus tendon tears who had ARCR show satisfactory short-term functional results. Although patients with traumatic tears have lower baseline functional scores, they rehabilitate over time and show comparable clinical results 1 year after ARCR. Similarly, degenerative and traumatic rotator cuff tears show comparable structural outcomes, which suggests that degenerated tendons retain healing potential.

Arthroscopic Middle Trapezius Transfer for Treatment of Irreparable Superior Rotator Cuff Tendon Tears.

Irreparable supraspinatus tendon tears are challenging to treat, especially in a young and high-demanding patient population. Whereas interposition tendon grafting and partial repair are limited by the quality of the remaining rotator cuff tendons and muscles, superior capsular reconstruction and subacromial spacers do not provide the active biomechanical principle of a contracting supraspinatus. The purpose of this technical note is to introduce an arthroscopic middle trapezius transfer below the acromion to replace the former supraspinatus unit. This technique might combine the benefits of both the static concepts seen with subacromial spacers or superior capsular reconstruction and dynamic concepts such as interposition grafting and partial repairs.

Middle trapezius transfer for treatment of irreparable supraspinatus tendon tears- anatomical feasibility study.

PURPOSE: The purpose of this study was to investigate the anatomical feasibility of a middle trapezius transfer below the acromion for treatment of irreparable supraspinatus tendon tears. METHODS: This study involved 20 human cadaveric shoulders in 10 full-body specimens. One shoulder in each specimen was dissected and assessed for muscle and tendon extent, force vectors, and distance to the neurovascular structures. The opposite shoulder was used to evaluate the surgical feasibility of the middle trapezius transfer via limited skin incisions along with an assessment of range of motion and risk of neurovascular injury following transfer. RESULTS: The harvested acromial insertion of the middle trapezius tendon showed an average muscle length of 11.7 ± 3.0 cm, tendon length of 2.7 ± 0.9 cm, footprint length of 4.3 ± 0.7 cm and footprint width of 1.4 ± 0.5 cm. The average angle between the non-transferred middle trapezius transfer and the supraspinatus was 33 ± 10° in the transversal plane and 34 ± 14° in the coronal plane. The mean distance from the acromion to the neurovascular bundle was 6.3 ± 1.3 cm (minimum: 4.0 cm). During surgical simulation there was sufficient excursion of the MTT without limitation of range of motion in a retracted scapular position but not in a protracted position. No injuries to the neurovascular structures were noted. CONCLUSION: Transfer of the acromial portion of the middle trapezius for replacement of an irreparable supraspinatus seems to be feasible in terms of size, vector, excursion, mobility and safety. However, some concern regarding sufficiency of transfer excursion remains as scapula protraction can increase the pathway length of the transfer. LEVEL OF EVIDENCE: Basic Science Study/Anatomical Study.

Shoulder-Pacemaker Treatment Concept for Posterior Positional Functional Shoulder Instability: A Prospective Clinical Trial.

BACKGROUND: Pathological muscle activation patterns of the external rotators and periscapular muscles can result in posterior positional functional shoulder instability (PP-FSI). In several patients, physical therapy and surgical treatment are not successful. PURPOSE: The shoulder-pacemaker treatment concept was evaluated prospectively in patients with PP-FSI and previously failed conventional therapy attempt. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: A negative selection of 24 consecutive cases of noncontrollable PP-FSI in 16 patients with previously failed conventional therapy were included in this prospective study. The shoulder-pacemaker treatment consisted of an electrical muscle stimulation-based therapy protocol with 9 to 18 one-hour treatment sessions. Two patients were excluded because of nonadherence to the training schedule, leaving a final study cohort of 21 cases in 14 patients. Follow-up included assessment of clinical function, impairment during daily activities and sports, satisfaction, Western Ontario Shoulder Instability Index (WOSI), Rowe score, and Subjective Shoulder Value at 0 weeks, 2 weeks, 4 weeks, 3 months, 6 months, 12 months, and 24 months after intervention. RESULTS: WOSI, Subjective Shoulder Value, and Rowe score showed a highly significant improvement at all time points of follow-up (P < .001). Young age (P = .005), low weight (P = .019), shoulder activity level (P = .003), unilateral affliction (P = .046), and higher baseline WOSI score (P = .04) were associated with a better treatment effect. Cases with increased glenoid retroversion, posterior scapulohumeral decentering, and dysplastic bony glenoid shape showed a trend toward shorter treatment effect duration. No complications during the intervention or follow-up period were observed. CONCLUSION: The shoulder-pacemaker therapy concept is an effective treatment with rapid improvement and sustained outcome over the course of 2 years in patients with noncontrollable PP-FSI with previously failed conventional treatment. Young and more athletic patients with lower weight and unilateral pathology respond best to the treatment.

Clinical and Radiographic Outcomes After Surgical Treatment of Proximal Humeral Fractures with Head-Split Component.

BACKGROUND: Head-split fractures are a subgroup of proximal humeral fractures in which the fracture line affects the articular surface. Limited data are available regarding outcomes and risk factors for failure following surgical treatment of this rare fracture type. METHODS: Of 45 patients with head-split fractures identified, a total of 30 (67%) were included in this retrospective study, with a mean follow-up of 49 ± 18 months (range, 12 to 83 months). Of those 30, 24 were treated with open reduction and internal fixation (ORIF), 4 with reverse total shoulder arthroplasty (RTSA), and 2 with hemiarthroplasty. Subjective Shoulder Value, Simple Shoulder Test, Constant score, and biplanar radiographs were assessed. Fracture pattern, quality of reduction, eventual complications, revision procedures, and clinical failure (adjusted Constant score < 40) were analyzed, and risk factors for failure were calculated. RESULTS: The overall complication rate was 83% (ORIF: 21 of 24 [88%]; RTSA: 3 of 4 [75%]; and hemiarthroplasty: 1 of 2 [50%]). The most common complications following ORIF were humeral head osteonecrosis (42%), malunion of the lesser tuberosity (33%), and screw protrusion (29%), whereas all complications following RTSA were related to tuberosity problems. Revision was performed in 7 of 24 (29%) of initial ORIF patients, and no revisions were performed in RTSA or hemiarthroplasty patients. Four patients (17%) who underwent primary ORIF underwent conversion to RTSA, and 3 patients (12.5%) had screw removal due to penetration. The overall clinical failure rate was 50% (ORIF: 12 of 24 [50%]; RTSA: 1 of 4 [25%]; and hemiarthroplasty: 2 of 2 [100%]). No significant association was found between preoperative factors and clinical failure. ORIF and primary RTSA showed higher average clinical outcome scores than primary hemiarthroplasty and secondary RTSA. In general, patients who required revision had worse Subjective Shoulder Value (p = 0.014), Simple Shoulder Test (p = 0.028), and adjusted Constant scores (p = 0.069). CONCLUSIONS: Head-split fractures of the humerus treated with ORIF showed high complication and revision rates. RTSA resulted in comparable clinical outcomes and complication rates; however, the complications associated with RTSA were mostly related to tuberosity problems, which in this small series did not require revision. Therefore, RTSA may be the most predictable treatment option for head-split fractures in elderly patients. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete list of levels of evidence.

Use of shoulder pacemaker for treatment of functional shoulder instability: Proof of concept.

BACKGROUND: Functional shoulder instability (polar type III) is caused by underactivity of rotator cuff and periscapular muscles, which leads to subluxation or dislocation during shoulder movement. While surgical treatment has shown no benefits, aggravates pain, and frequently diminishes function even further, conservative treatment is often ineffective as well. OBJECTIVES: The aim was to investigate the effectiveness of a "shoulder pacemaker" device that stimulates underactive muscles in patients with functional instability during shoulder movement in order to re-establish glenohumeral stability. PATIENTS AND METHODS: Three patients with unsuccessfully treated functional shoulder instability causing pain, emotional stress, as well as limitations during daily activities and sports participation were enrolled in this pilot project. The device was used to stimulate the external rotators of the shoulder and retractors of the scapula. Pain level, subjective shoulder instability, range of motion, visible aberrant muscle activation, and signs of dislocation were compared when the device was switched on and off. RESULTS: No changes were observed when the device was attached but switched off. When the device was switched on, all patients were able to move their arms freely without pain, discomfort, or subjective or objective signs of instability. All patients rated this as an excellent experience and volunteered to train further with the device. No complications were observed. CONCLUSION: The electric stimulation of hypoactive rotator cuff and periscapular muscles by means of the shoulder pacemaker successfully re-establishes stability in patients with functional shoulder instability during the time of application. VIDEO ONLINE: The online version of this article (doi: 10.1007/s11678-017-0399-z) contains the video: "The Shoulder-Pacemaker: treatment of functional shoulder instability with pathological muscle activation pattern". Video by courtesy of P. Moroder, M. Minkus, E. Böhm, V. Danzinger, C. Gerhardt and M. Scheibel, Charité Universitätsmedizin Berlin 2017, all rights reserved.