Trends in the surgical management of proximal humerus fractures in Ireland from 2009 to 2022: An increasing usage of reverse shoulder arthroplasty.

BACKGROUND: Proximal humeral fractures are a common injury accounting for a significant workload across orthopaedic departments. Though often managed non-operatively, surgical management is indicated for a proportion of patients. AIMS: The aim of this study is to examine the trends in the management of proximal humeral fractures within Ireland over the past 13 years. METHODS: A retrospective review of Irish Hospital In-Patient Enquiry (HIPE) data was performed between January 2009 and December 2022. Information regarding demographics including age and gender, along with procedure type were collated after patients with proximal humerus fractures, were identified using relevant ICD 10 codes. RESULTS: Demographic details remained stable with females and those within the 55-69 year age bracket accounting for the highest proportion of patients. The mean annual number of procedures performed across the study period was 365 (273-508), with an increase from 288 cases in 2009 to 441 in 2022. Open reduction and internal fixation were the most common procedures accounting for 76.4% of cases. There has been a rising usage of total shoulder arthroplasty for fixation with an increase from < 5 cases in 2016 to 84 in 2022. A decrease in the usage of hemiarthroplasty and closed reduction internal fixation was also observed. CONCLUSIONS: There has been an increasing volume of operatively managed proximal humeral fractures in Ireland, which sustained despite the 2015 publication of the highly publicised PROPHER trial. The increasing utilisation of total shoulder arthroplasty in acute trauma management is notable and necessitates appropriate training for trauma theatre personnel.

A Biomechanical Comparison of Different Suture Materials Used for Arthroscopic Shoulder Procedures.

PURPOSE: To evaluate the viscoelastic properties of 4 commercially available cord-like sutures and 2 commercially available suture tapes when subjected to physiological loads, as well as to compare them with each other and to identify the clinically most desirable combination of suture material properties. METHODS: Six suture materials (Ethibond, FiberWire, FiberTape, Orthocord, Ultrabraid, and Ultratape) underwent creep testing (n = 7, 60 N, 10 minutes) to determine specimen stiffness, initial elongation at 60 N of load, static creep (during 10 minutes of loading), and relaxed elongation (material recovery 3 minutes after removal of load). Furthermore, cyclic testing (n = 7, 10-45 N, 0.5 Hz, 500 cycles) was carried out to determine dynamic creep, peak-to-peak displacement, and relaxed elongation. Mechanical testing was conducted on a material testing machine in 37°C phosphate-buffered saline solution. RESULTS: FiberTape showed the greatest stiffness (23.9 ± 3.2 N/mm, P < .001), the smallest amounts of static (0.38 ± 0.10 mm, P < .001) and dynamic (0.16 ± 0.09 mm, P = .003) creep, and the smallest peak-to-peak displacement (0.20 ± 0.02 mm, P < .001). FiberTape and FiberWire showed the smallest initial elongation (1.17 ± 0.17 mm and 1.63 ± 0.25 mm, respectively; P < .001). Ultrabraid showed the greatest relaxed elongation, both statically (4.73 ± 0.73 mm, P < .001) and dynamically (4.18 ± 0.83 mm, P = .002). CONCLUSIONS: FiberTape consistently displayed less creep, greater stiffness, and less extensibility than the other suture types. Ultrabraid showed the largest amount of relaxed elongation on both static and dynamic testing. CLINICAL RELEVANCE: When considering high stiffness in combination with low initial extension and low static creep to be ideal parameters to achieve optimal initial construct stability and considering low dynamic creep in combination with low peak-to-peak displacement to be ideal conditions for the repetitive loading of the construct during the healing process, tapes seem to be superior to cord-like sutures for performing rotator cuff repair.

Video Analysis of Shoulder Dislocations in Rugby: Insights Into the Dislocating Mechanisms.

BACKGROUND: Mechanisms previously described for traumatic shoulder injuries in rugby may not adequately describe all the mechanisms that result in shoulder dislocations. PURPOSE: To investigate the mechanism of shoulder dislocation events in professional rugby players through use of systematic video analysis. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: In our series, 39 cases of shoulder dislocations from games played in top professional leagues and international matches across a 2-year period were available for video analysis. All cases were independently assessed by 2 analysts to identify the sequence of events occurring during shoulder dislocation. This included injury circumstance such as contact with another player or the ground, game scenario, injury timing, and the movements and force vectors involved in the dislocation mechanism. RESULTS: We identified 4 distinct injury mechanisms. The previously described mechanisms "try scorer,""tackler," and "direct impact" were identified in 67% of cases. We describe a new injury mechanism occurring in the "poach position," accounting for 18% of all shoulder dislocations studied. The remaining 15% could not be categorized. Shoulder dislocations occurred to a ball carrier in 15% of cases (n = 6) and a non-ball carrier in 85% of cases (n = 33). The injury most commonly occurred during a tackle (49%; n = 19) followed by ruck/maul (26%; n = 10). Time of injury showed that 36% (n = 14) of cases occurred in the last quarter of the game. CONCLUSION: Shoulder dislocations have now been shown to occur predominantly as a result of 1 of 4 distinct mechanisms, most frequently in the second half of the game. A new mechanism for shoulder dislocation has been described in this series, termed the poach position.

Do preoperative radiographs help predict intraoperative challenges in revision surgery after previous shoulder hemiarthroplasty?

BACKGROUND: This study compares preoperative radiographic evaluation with intraoperative video and explant data in patients undergoing revision of a hemiarthroplasty. METHODS: From 2004 to 2017, 182 shoulder hemiarthroplasties underwent revision to reverse shoulder arthroplasty for symptomatic failure. Preoperative radiographs were evaluated for stem fixation, stability, and glenohumeral registry. Intraoperative videos (n = 48) were evaluated for humeral component stability and bone loss after humeral stem extraction. All explants (n = 83) were reviewed for humeral head wear patterns and extraction artifacts (EAs). RESULTS: A well-fixed stem was reliably identified on radiographs as well fixed (true-negative rate, 95%). Of cemented implants, 94% (97 of 103) were radiographically stable and 90% (18 of 20) were stable on intraoperative video. Significant proximal humeral bone loss was identified after cemented stem extraction in 83% of cases, and severe EAs were noted in 28% (14 of 50). Of uncemented implants, 95% (75 of 79) were radiographically stable and 96% (24 of 25) were operatively stable. Significant proximal humeral bone loss was identified after extraction in 36% of cases (9 of 25) (P = .001). Severe EAs were seen in 13% of explanted stems (3 of 23). Eccentrically worn humeral head explants were associated with eccentric glenohumeral registry in 84% of cases (P = .0075). CONCLUSION: Preoperative radiographs for revision of a failed hemiarthroplasty help identify well-fixed stems and predict humeral bone loss during extraction. Cemented stems will have more EAs and result in greater bone loss than uncemented stems. Glenohumeral registry can help to predict humeral head wear. Eccentric registry leads to eccentric humeral head wear in 84% of cases.

Improving preoperative planning of revision surgery after previous anatomic total shoulder arthroplasty.

BACKGROUND: The purpose of this study was to compare preoperative radiographic evaluation with intraoperative video and explant analysis in patients undergoing revision of a previous anatomic total shoulder arthroplasty (TSA). METHODS: We evaluated the preoperative radiographs of 165 revisions of failed TSAs for component loosening and glenohumeral registry (ie, the spatial relationship of the glenoid component and the prosthetic humeral head). Seventy-nine intraoperative videos were evaluated for component stability, rotator cuff (RC) integrity, synovitis, and glenoid bone loss. Eighty-seven explants were reviewed to assess wear patterns and presence of backside cement. RESULTS: Of 79 glenoid components, 47 were radiographically loose, but only 30 of 79 were loose intraoperatively. Thirty-two were radiographically fixed, but only 26 of 32 were fixed intraoperatively. If radiographically loose, 53% had severe glenoid bone loss. If radiographically fixed, 77% had mild to moderate bone loss (P = .008). Synovitis was associated with glenoid fixation: mild with a loose glenoid (6%) and severe with a fixed glenoid (30%, P = .012). Superior registry comprised 46%. RC deficiency was associated with posterior and anterior registry (88% and 79%, respectively). Explant examination revealed an eccentric wear pattern was predominant. CONCLUSION: Radiographic evaluation of glenoid loosening in patients undergoing revision of TSAs will often differ from intraoperative findings (40% false-positive rate and 17% false-negative rate). Assessment of glenohumeral registry can help anticipate RC deficiency, with posterior and anterior registry associated with RC deficiency. Patients with a loose glenoid are more likely to have severe synovitis and more severe glenoid bone deficiencies. Failed TSAs are more likely to have asymmetrical wear of the glenoid component, suggesting altered pathomechanics that may have led to failure.

Bioabsorbable pins for bone fixation in the less invasive innominate osteotomy.

For the less invasive innominate osteotomy for the treatment of developmental dysplasia of the hip, we aim to report radiological outcomes, complication rates and reoperation rates for patients whose bone grafts were secured using bioabsorbable pins. A retrospective study of all patients who underwent less invasive innominate osteotomy for persistent or delayed diagnosis developmental dysplasia of the hip over a period of 2 years from 2008 to 2010 was carried out. A total of 59 hips were identified as having had their bone graft secured with two bioabsorbable pins made from copolymers of L-lactic acid, D-lactic acid and trimethylene carbonate. The average angular correction of the acetabular index in the bioabsorbable group at late follow-up was 16.48° (P<0.0001). Seven percent of patients from the bioabsorbable pin group went on to require reoperation for persistent dysplasia. No patient required reoperation due to implant failure. There was no incidence of postoperative wound infection or other complication requiring medical or surgical intervention. These results demonstrate that the use of bioabsorbable pins to secure the bone graft is as effective and safe as metal fixation.

Use of a geometric formula to improve the radiographic correction achieved by the scarf osteotomy.

BACKGROUND: Many procedures for hallux valgus treatment have high recurrence rates, often related to operative considerations such as accuracy of deformity correction, soft tissue balancing and sesamoid alignment. Inadequate distal metatarsal-articular angle (DMAA) correction is common with uni- and bi-planar osteotomies which principally address the inter-metatarsal angle (IMA). The scarf osteotomy is a tri-planar osteotomy which corrects the DMAA and IMA, thereby achieving a more anatomical correction and potentially reducing the recurrence rate. Our hypothesis was that by controlling the length and relative proximal and distal translations of the scarf with a geometric formula, more accurate correction of the IMA and DMAA is possible. METHODS: A formula was generated to determine the specific adjustments required to correct the deformity. A prospective trial was performed to assess the accuracy of this formula. Thirty-four adult patients were enrolled in the study. Seventeen patients underwent a standard scarf procedure; 17 were operated on using the corrections prescribed by the formula. RESULTS: Hallux valgus angle (HVA), IMA and DMAA corrections improved with the formula (p = 0.036, p = 0.049, and p = 0.006, respectively). Patient and procedure selection has changed in our unit as a result of this study, which identified some preoperative deformities as beyond the capabilities of the scarf procedure. CONCLUSION: The formula allows precise, reproducible, anatomical correction of IMA and DMAA deformities. The degree of correction attainable with the scarf is dependent on the first metatarsal width and the preoperative deformities. The formula highlighted the limitations of the scarf, thereby aiding in appropriate patient and procedure selection.

N-acetylcysteine protects striated muscle in a model of compartment syndrome.

BACKGROUND: To avoid ischemic necrosis, compartment syndrome is a surgical emergency treated with decompression once identified. A potentially lethal, oxidant-driven reperfusion injury occurs after decompression. N-acetylcysteine is an antioxidant with the potential to attenuate the reperfusion injury. QUESTIONS/PURPOSES: We asked whether N-acetylcysteine could preserve striated muscle contractility and modify neutrophil infiltration and activation after simulated compartment syndrome release. MATERIALS AND METHODS: Fifty-seven rats were randomized to control, simulated compartment syndrome, and simulated compartment syndrome plus N-acetylcysteine groups. We isolated the rodent cremaster muscle on its neurovascular pedicle and placed it in a pressure chamber. Chamber pressure was elevated above critical closing pressure for 3 hours to simulate compartment syndrome. Experiments were concluded at three times: 1 hour, 24 hours, and 7 days after decompression of compartment syndrome. We assessed twitch and tetanic contractile function and tissue myeloperoxidase activity. Ten additional rats were randomized to control and N-acetylcysteine administration after which neutrophil respiratory burst activity was assessed. RESULTS: The simulated compartment syndrome decreased muscle contractility and increased muscle tissue myeloperoxidase activity compared with controls. Treatment with N-acetylcysteine preserved twitch and tetanic contractility. N-acetylcysteine did not alter neutrophil infiltration (myeloperoxidase activity) acutely but did reduce infiltration at 24 hours, even when given after decompression. N-acetylcysteine reduced neutrophil respiratory burst activity. CONCLUSION: N-acetylcysteine administration before or after simulated compartment syndrome preserved striated muscle contractility, apparently by attenuating neutrophil activation and the resultant oxidant injury. CLINICAL RELEVANCE: Our data suggest a potential role for N-acetylcysteine in the attenuation of muscle injury after release of compartment syndrome and possibly in the prophylaxis of compartment syndrome.

A pilot evaluation of a neuromuscular electrical stimulation (NMES) based methodology for the prevention of venous stasis during bed rest.

Bed rest poses an increased risk factor for a potentially fatal venous thromboembolism (VTE). Lack of activation of the calf muscle pump during this resting period gives rise to venous stasis which may lead to deep vein thrombosis (DVT) development. Our aim was to investigate the effects that 4h of bed rest have on the lower limb hemodynamics of healthy subjects and to what extent electrically elicited contractions of the calf muscles can alleviate these effects. Outcome variables included popliteal vein blood flow and heart rate. Primary results indicated that the resting group experienced a significant decline in popliteal venous blood flow of approximately 47% with approximately 13% decrease in heart rate. The stimulated groups maintained a significantly higher venous blood flow and heart rate. Volume flow in the contralateral limb remained constant throughout the study and was comparable to that of the stimulated limb's recovery flow. The results suggest that even short periods of bed rest can significantly reduce lower limb blood flow which could have implications for DVT development. Electrically elicited calf muscle contractions significantly improve lower limb blood flow and can alleviate some debilitating effects of bed rest.

A hemodynamic study of popliteal vein blood flow: the effect of bed rest and electrically elicited calf muscle contractions.

Venous stasis, due to lack of activation of the calf muscle pump of postoperative patients, can result in the development of a thrombus which, in turn, can lead to a potentially fatal pulmonary embolism. The presented study investigates the effects that four hours of bed rest has on the lower limb hemodynamics of healthy subjects and, to what extent electrically elicited contractions of the calf muscles can alleviate these effects. Results indicated that the non-stimulated group experienced a decline in popliteal venous blood flow of approximately 45 % and a 10 % decrease in heart rate. The stimulated group maintained a higher venous blood flow and heart rate. The results suggest that even short periods of bed rest can significantly reduce lower limb blood flow which could have implications for DVT development in post-operative patients. Electrically elicited calf muscle contractions significantly improves lower limb blood flow and can alleviate the debilitating effects of bed rest.