Edwin R. Cadet

Tendon-to-Bone Pressure Distributions at a Repaired Rotator Cuff Footprint Using Transosseous Suture and Suture Anchor Fixation Techniques

Background Interface contact pressure between the tendon and bone has been shown to influence healing. This study evaluates the interface pressure of the rotator cuff tendon to the greater tuberosity for different rotator cuff repair techniques. Hypothesis The transosseous tunnel rotator cuff repair technique provides larger pressure distributions over a defined insertion footprint than do suture anchor techniques. Study Design Controlled laboratory study. Methods Simulated rotator cuff tears over a 1 × 2-cm infraspinatus insertion footprint were created in 25 bovine shoulders. A transosseous tunnel simple suture technique (n = 8), suture anchor simple technique (n = 9), and suture anchor mattress technique (n = 8) were used for repair. Pressurized contact areas and mean pressures of the repaired tendon against the tuberosity were determined using pressure-sensitive film placed between the tendon and the tuberosity. Results The mean contact area between the tendon and tuberosity insertion footprint was significantly greater for the transosseous technique (67.7 ± 5.8 mm2) compared with the suture anchor simple (34.1 ± 9.4 mm2) and suture anchor mattress (26.0 ±5.3 mm2) techniques (P < .05). The mean interface pressure exerted over the footprint by the tendon was also greater for the transosseous technique (0.32 ± 0.05 MPa) compared with the suture anchor simple (0.26 ± 0.04 MPa) and suture anchor mattress (0.24 ± 0.02 MPa) techniques (P < .05). Conclusion The transosseous tunnel rotator cuff repair technique creates significantly more contact and greater overall pressure distribution over a defined footprint when compared with suture anchor techniques. Clinical Relevance Stronger and faster rotator cuff healing may be expected when beneficial pressure distributions exist between the repaired rotator cuff and its insertion footprint. Tendon-to-tuberosity pressure and contact characteristics should be considered in the development of improved open and arthroscopic rotator cuff repair techniques.

Investigation of the Preservation of the Fluid Seal Effect in the Repaired, Partially Resected, and Reconstructed Acetabular Labrum in a Cadaveric Hip Model

Background: Debate exists on whether hip labral tears should be surgically repaired, partially resected, or reconstructed. Furthermore, limited data exist regarding the fluid seal properties of hip labrum repair and/or reconstruction with iliotibial band autograft when compared with the labrum-intact condition. Hypothesis/Purpose: The purpose of this study was to investigate the fluid seal properties of hip labral repair and reconstruction techniques. We hypothesized that hip labral repair preserves the acetabular labral fluid seal greater than labral tear, partial-resection, and reconstruction conditions. Study Design: Controlled laboratory study. Methods: Six human cadaveric hemipelvises were dissected of all soft tissue, leaving the hip capsule intact. Fluid efflux was measured under 5 conditions using a custom fluid infusion device: (1) hip labrum intact, (2) labral tear, (3) labral repair with suture anchors, (4) partial labral resection, and (5) labral reconstruction using ipsilateral iliotibial band autograft. Joint fluid expression was measured as flow rate under 3 different pressure settings (2, 3, and 4 psi). Statistical differences between conditions were assessed using 2-way, repeated-measures analysis of variance. The Student-Newman-Keuls (SNK) multiple comparison test was used to determine differences between levels. Results: There was a significant increase in fluid efflux with a simulated labral tear (0.54 ± 0.3 mL/sec) when compared with the intact hip labrum condition (0.006 ± 0.008 mL/sec, P < .05). The labrum-repaired condition (0.21 ± 0.2 mL/sec) demonstrated significantly less fluid efflux when compared with the labral-tear condition. Hip labral repair significantly prevented greater fluid efflux when compared with partial labral resection (0.60 ± 0.4 mL/sec) and reconstruction with iliotibial band autograft (0.54 ± 0.3 mL/sec; P < .05). Labral repair did not preserve fluid efflux as effectively as in the labrum-intact condition (0.21 ± 0.2 > 0.006 ± 0.008 mL/sec; P < .05). There was no difference observed in fluid efflux between the labral reconstruction, tear, or resection conditions (P > .05). Conclusion: In this human cadaveric model, hip labral repair outperforms partial labral resection and reconstruction in preserving the joint fluid seal; however labral repair does not restore fluid seal characteristics as effectively as in the labrum-intact condition. Clinical Relevance: Further prospective studies are needed to determine whether hip labral repair outperforms partial labral resection and/or reconstruction in clinical practice.

Hemiarthroplasty for Three- and Four-part Proximal Humerus Fractures

Abstract Displaced three‐ and four‐part proximal humerus fractures are among the most challenging shoulder conditions to manage. Because of the risk of symptomatic malunion, nonunion, and humeral head osteonecrosis, surgical management is preferred. Locking plate technology has provided an alternative to hemiarthroplasty for certain three‐ and four‐part fracture patterns, even in the setting of osteopenic bone. Prosthetic humeral head replacement has been advocated for head‐splitting fractures and fracture‐dislocations as well as four‐part fractures with significant initial varus displacement (>20°). Technical challenges, including obtaining proper humeral head height, retroversion, and optimal positioning and fixation of the tuberosities, have a substantial effect on patient outcomes.

Proximal humerus and humeral shaft nonunions.

&NA; The rate of nonunion is estimated to be 1.1% to 10% following closed treatment of proximal humerus fracture and 5.5% following closed treatment of humeral shaft fracture. Surgical management should be considered for fractures that demonstrate no evidence of progressive healing on consecutive radiographs taken at least 6 to 8 weeks apart during the course of closed treatment. In the case of proximal humerus nonunion, recent series have demonstrated union in >90% of patients treated with reconstruction using locking plates and autogenous bone graft. Shoulder arthroplasty is reserved as a salvage option in cases in which the humeral head is not viable or the proximal fragment will not support osteosynthesis. For humeral shaft nonunions, open reduction and internal fixation with compression plating and bone graft remains the standard of care, with a >90% rate of union and good functional outcomes. Recent studies support the use of locked compression plates, dual plating, and cortical allograft struts in patients with osteopenic bone.

Improving Bone Density at the Rotator Cuff Footprint Increases Supraspinatus Tendon Failure Stress in a Rat Model

The purpose of this study was to investigate whether supraspinatus tendon failure stress at the footprint can increase by improving the bone density at the rotator cuff footprint in a rat model. Bilateral ovariectomies were performed in twenty‐four 4‐month‐old Sprague‐Dawley rats. Half received bisphosphonate (zoledronic acid) and the other half received no treatment (OVX + ZOM and OVX, respectively). Twelve additional rats did not undergo ovariectomy or receive bisphosphonate treatment (CON). All rats were sacrificed at 7 months of age. Quantitative micro‐computed tomography was used to assess bone density in the proximal humerus. A series of stress–relaxation tests were performed to assess stiffness and failure stress of the supraspinatus tendon. Bone density in OVX + ZOM was significantly higher at the rotator cuff footprint when compared to CON and OVX rats (p < 0.0001). The supraspinatus tendons in the OVX group were significantly stiffer when compared to the CON and OVX + ZOM groups (p < 0.05). The failure stress of the OVX + ZOM group was significantly greater than the CON and OVX groups (22.89 ± 4.43 MPa vs. 18.36 ± 3.16 and 17.70 ± 4.92, respectively). In conclusion, improving the bone density at the rotator cuff footprint enhances failure stress of the suprapinatus tendon.

Management of Septic Arthritis Following Anterior Cruciate Ligament Reconstruction: A Review of Current Practices and Recommendations

Abstract Septic arthritis following anterior cruciate ligament reconstruction is a rare and potentially devastating complication that often leads to articular destruction and adverse clinical outcomes. Because of its rare occurrence, best practices for diagnosis and management have yet to be established. However, graft retention and favorable outcomes are possible with early diagnosis, surgical intervention, and appropriate antibiotic management. Clinicians must be familiar with the diagnostic criteria and management options for septic arthritis. Most patients require multiple procedures to effectively eradicate infection. When the original reconstructed graft cannot be salvaged, a staged anterior cruciate ligament reconstruction revision is required.

Evaluation of Glenohumeral Instability

Glenohumeral instability is a common cause of shoulder disability. A wide spectrum of causes and presentations can make diagnosing subtle instability very difficult. This article describes clinical evaluation of the glenohumeral joint using pertinent components of the patient history, physical examination, and selective imaging to arrive at the diagnosis of glenohumeral instability in the symptomatic patient.

Superior labrum anterior-to-posterior repair incidence: a longitudinal investigation of community and academic databases

BACKGROUND Superior labrum anterior-to-posterior (SLAP) lesion repair is controversial regarding indications and potential complications. METHODS Databases were used to determine the SLAP repair incidence compared with all orthopaedic procedures over a period of 10 years. In part A, the New York Statewide Planning and Research Cooperative System ambulatory surgery database was investigated from 2002 to 2009. In part B, the California Office of Statewide Health Planning and Development ambulatory surgery database was investigated from 2005 to 2009. In part C, the American Board of Orthopaedic Surgery (ABOS) database was investigated from 2003 to 2010. RESULTS In part A, from 2002 to 2009, there was a 238% increase in SLAP repair volume compared with a 125% increase in all orthopaedic procedures. In part B, from 2005 to 2009, there was a 20.17% increase in SLAP repair volume compared with a decrease of 13.64% in all orthopaedic procedures. In part C, among candidates performing at least 1 SLAP repair, there was no statistically significant difference in likelihood of performing a SLAP repair (95% confidence interval, 0.973-1.003) in 2010 as compared with 2003 (P > .10). CONCLUSIONS There has been a significant increase in the incidence of SLAP repairs in the past 10 years in statewide databases. This pattern was not seen in the ABOS database, in which the annual volume of SLAP repairs remained stable over the same period. This suggests that SLAP lesions have been over-treated with surgical repair but that part II ABOS candidates are becoming more aware of the need to narrow indications. LEVEL OF EVIDENCE Epidemiology study, database analysis.

Aggravation of inflammatory response by costimulation with titanium particles and mechanical perturbations in osteoblast- and macrophage-like cells

The interface between bone tissue and metal implants undergoes various types of mechanical loading, such as strain, compression, fluid pressure, and shear stress, from daily activities. Such mechanical perturbations create suboptimal environments at the host bone-implant junction, causing an accumulation of wear particles and debilitating osseous integration, potentially leading to implant failure. While many studies have focused on the effect of particles on macrophages or osteoprogenitor cells, differential and combined effects of mechanical perturbations and particles on such cell types have not been extensively studied. In this study, macrophages and osteoprogenitor cells were subjected to physiological and superphysiological mechanical stimuli in the presence and absence of Ti particles with the aim of simulating various microenvironments of the host bone-implant junction. Macrophages and osteoprogenitor cells were capable of engulfing Ti particles through actin remodeling and also exhibited changes in mRNA levels of proinflammatory cytokines under certain conditions. In osteoprogenitor cells, superphysiological strain increased proinflammatory gene expression; in macrophages, such mechanical perturbations did not affect gene expression. We confirmed that this phenomenon in osteoprogenitor cells occurred via activation of the ERK1/2 signaling pathway as a result of damage to the cytoplasmic membrane. Furthermore, AZD6244, a clinically relevant inhibitor of the ERK1/2 pathway, mitigated particle-induced inflammatory gene expression in osteoprogenitor cells and macrophages. This study provides evidence of more inflammatory responses under mechanical strains in osteoprogenitor cells than macrophages. Phagocytosis of particles and mechanical perturbation costimulate the ERK1/2 pathway, leading to expression of proinflammatory genes.

Intermediate and long-term follow-up of total shoulder arthroplasty for the management of postcapsulorrhaphy arthropathy

BACKGROUND The purpose of this study was to evaluate the subjective and objective outcomes in patients undergoing total shoulder arthroplasty for treatment of postcapsulorrhaphy arthropathy (CA) and compare them with outcomes in patients undergoing total shoulder arthroplasty for primary glenohumeral osteoarthritis (OA). METHODS Total shoulder arthroplasty was used to treat 25 consecutive CA patients (25 shoulders) at our institution; of these, 22 patients were available for follow-up. An age-matched cohort of 19 consecutive patients (20 shoulders) who were treated with total shoulder arthroplasty for primary glenohumeral OA was compared with the CA group. Patients were evaluated by physical examination and patient outcome measures (American Shoulder and Elbow Surgeons assessment and Simple Shoulder Test). Complications, reoperations, and subscapularis function was also recorded. RESULTS Compared with the CA group, the OA group achieved greater forward elevation (165° vs 147°; P = .036) and greater external rotation (56° vs. 45°; P = .04); however, no significant differences were seen in subjective patient scores between the 2 groups for Simple Shoulder Test (P = .90), American Shoulder and Elbow Surgeons assessment (P = .65), and pain scores (P = .80). The difference in the number of revision surgeries in the OA group compared with the CA group (1 vs 4) was not significant (P = .35). A significantly higher number of patients in the CA group had subscapularis insufficiency compared with the OA group (5 CA vs 0 OA; P = .049). CONCLUSIONS Our findings suggest that when compared with patients undergoing total shoulder arthroplasty for primary OA, CA patients experience similar outcomes with respect to revision surgery, pain relief, and subjective self-assessment and have a higher incidence of subscapularis insufficiency.