Hemiarthroplasty for proximal humerus fractures with conservation of the whole humeral head as autograft: does it improve greater tuberosity healing?

Radiologic evaluation of the healing of the greater tubercle after humeral hemiarthroplasty with Aequalis-fracture-implants for proximal humeral fracture: a retrospective cohort study in 45 shoulders

INTRODUCTION

Development and use of specific anatomic prosthesis for shoulder's fracture aimed to reach the best rate of consolidation of the greater tubercle, which means a cuff restitution to improve functional results. The lack of bone healing of the tubercles suggested the use of a fenestrated humeral implant with interposition of a bone graft in the metaphyseal part of the prosthesis. This characteristic of specific implant, have few reports in the literature, leading us to the current retrospective study aiming: 1) to evaluate the healing rate of the greater tubercle after implantation of fracture dedicated anatomic implant, which includes a fenestration in the prosthetic metaphysis for the addition of a cortico cancellous graft, 2) to asses on patients with proximal humerus fractures, the bone healing of the greater tubercle close to the intraprosthetic bone graft.

HYPOTHESIS

The specific "implant-fracture" can achieve a high rate of bone healing of the humeral greater tubercle.

PATIENTS AND METHODS

Between January 2001 and December 2020, fifty-one patients were operated on by implantation of fracture dedicated implant for proximal humerus fracture. Six were excluded (2 operated for revision, 2 operated after 3 weeks, 1 died, 1 without follow-up). In total 45 patients were included in radiological analysis, clinical analysis had been performed on 23/45 patients at the longest follow up, the other 22/45 were only analyzed on radiographies. Mean-aged 66 years (range, 47 years -88 years), 25/45 (56%) of women, with 3-4-parts fractures according to Neer's classification. The techniques of tubercle fixation were isolated cerclages of combined horizontal cerclages and vertical sutures. Position and healing of the greater tubercle was controlled through antero-posterior and lateral X-Rays views at the longest follow-up (mean 50 months, range 3-193 months). Peroperative techniques of fixation, clinical and functional outcomes were noted and correlated to the radiologic position of the greater tubercle and the graft evolution. Factors associated with healing and anatomic position had been investigated.

RESULTS

The rate of greater tubercle healing was 32/45 (73%). Factors significantly associated with greater tuberosity consolidation were higher age (p = 0.04) and the addition of a vertical osteosuture to the horizontal suture of the greater tubercle (p = 0.01). The rate of anatomic position of the greater tubercle was 15/45 (33%) of cases. When the fixation of the tuberosity was made with vertical suture, good position of the tuberosity was observed in 68% (17/24) at the longest follow-up.

DISCUSSION

Our results were in accordance with the literature, but the current study underlined there were two types of factors influencing tubercle healing in the literature: the technique of fixation of the tubercle and the patient's age.

LEVEL OF EVIDENCE

level IV cohort study without control group.

Tuberosity reconstruction baseplate for shoulder hemiarthroplasty: Morphological design and biomaterial application

Background: Shoulder hemiarthroplasty is prone to tuberosity malposition and migration, reducing the rate of tuberosity healing. We proposed to design a tuberosity reconstruction baseplate to assist in tuberosity integration and to evaluate the mechanical properties of baseplate made from the novel biomaterial carbon fiber reinforced polymer (CFRP) composites.

Methods: The three-dimensional model of native proximal humerus was constructed by computed tomography (CT) data. The morphological design of baseplate was based on the tuberosity contour and rotator cuff footprint. Finite element models were created for different thicknesses of CFRP composites, poly (ether-ether-ketone) (PEEK) and titanium-nickel (TiNi) alloy. The permissible load and suture hole displacements were applied to evaluate the mechanical properties.

Results: The structurally optimized model made of CFRP composites provided superior strength and deformability, compared to the PEEK material and TiNi alloy. Its permissible load was above 200 N and the suture hole displacement was between 0.9 and 1.4 mm.

Conclusion: This study proposed a method for designing tuberosity reconstruction baseplate based on morphological data and extended the application of biomaterial CFRP composites in orthopedics field. The optimized model made of CFRP composites allowed a certain extent of elastic deformation and showed the possibility for dynamic compression of tuberosity bone blocks.

Bone resorption of the greater tuberosity after open reduction and internal fixation of complex proximal humeral fractures: fragment characteristics and intraoperative risk factors

HYPOTHESIS AND BACKGROUND

In complex proximal humeral fractures, bone resorption of the greater tuberosity is sometimes observed after open reduction and internal fixation (ORIF). However, this has not been well characterized, and risk factors for resorption are not completely understood. We aimed (1) to identify the risk factors associated with bone resorption of the greater tuberosity and (2) to quantify the geometric and bone density characteristics associated with bone resorption using 3-dimensional computed tomography models in complex proximal humeral fractures treated with ORIF.

METHODS

We identified a retrospective cohort of 136 patients who underwent ORIF of 3- or 4-part proximal humeral fractures; greater tuberosity resorption developed after ORIF in 30 of these patients. We collected demographic, fracture-related, and surgery-related characteristics and performed multivariable logistic regression analysis to identify factors independently associated with the development of greater tuberosity resorption. Furthermore, we identified 30 age- and sex-matched patients by use of propensity score matching to perform quantitative fragment-specific analysis using 3-dimensional computed tomography models. After the fragment of the greater tuberosity was identified, the number of fragments, the relative fragment volume to the humeral head, and the relative bone density to the coracoid process were calculated. Measurements were compared between matched case-control groups.

RESULTS

We found that an unreduced greater tuberosity (odds ratio [OR], 10.9; P < .001), inadequate medial support at the calcar (OR, 15.0; P < .001), and the use of an intramedullary fibular strut (OR, 4.5; P = .018) were independently associated with a higher risk of bone resorption. Quantitative fragment-specific analysis showed that greater tuberosities with a larger number of fragments (5 ± 2 vs. 3 ± 2, P = .021), smaller fragments (9.9% ± 3.8% vs. 18.6% ± 4.7%, P < .001), and fragments with a lower bone density (66.4% ± 14.3% vs. 88.0% ± 18.4%, P = .001) had higher rates of resorption.

DISCUSSION AND CONCLUSION

An unreduced greater tuberosity or inadequate medial support increases the risk of greater tuberosity resorption, as do a larger number of fracture fragments, smaller fragments, and lower bone density. Additionally, fibular strut grafting is an independent risk factor for tuberosity resorption. Further study is needed, but alternatives to strut grafting such as femoral head allograft may warrant serious consideration.

[Research progress of greater tubercle fixation and rotator cuff repair in humeral head replacement]

OBJECTIVE

To summarize the research progress of the greater tubercle fixation and the rotator cuff repair in humeral head replacement.

METHODS

The literature about proximal humerus fracture and humeral head replacement in recent years was extensively consulted and analyzed.

RESULTS

The greater tubercle fixation and the attached rotator cuff repair have great influence on the function of shoulder joint after humeral head replacement. It is difficult to make an objective comparison because of lack of direct comparison between various methods, unified standards of grading, and limited number of cases.

CONCLUSION

It is an important factor of reduction and fixation of greater tubercle to obtain better effectiveness in humeral head replacement. However, one-stage repair of rotator cuff is more important than greater tubercle fixation for functional recovery of shoulder joint.