Optimization of tuberosity fixation using looped thread osteosuture Anatomical work and prospective multicentre clinical study

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1 Optimization of tuberosity fixation using looped thread osteosuture Anatomical work and prospective multicentre clinical study T Lascar(Monaco), S Rochet (Besancon), A Adam (Besancon), N Gasse (Besancon), JY Hery (Manosque), Y Bellumore (Toulouse), J Podlagen (Douai), M Lahmeri (Argenteuil), N Debit (Poissy), A Cobileac (Lons), G Polveche (Lille), L Obert (Besancon) Introduction Functional results in hemiarthroplasty in 4 part displaced fractures (complex cephalotuberosity) correlate with the height position of the implant and the anatomical consolidation of the tuberosities But this osteo-tendon structural fixation technique for this type of fracture remains a therapeutic challenge and faces many obstacles Tuberosity fixation is in effect based on an osteosuture and markers which are difficult to locate per operatively, and are therefore not easily monitored by the surgeon The evolution of the design of shoulder prostheses for fracture cases is an indirect sign that the best implant is yet to be invented so as to be able to provide at the patient s level an anatomical reconstruction of the proximal humerus We are reporting on an evaluation of tuberosity fixation using looped thread and modular metaphyseal prosthesis Should tuberosities really be reconstructed? In cases of cephalo tuberosity fracture of the proximal humerus, permanent reconstruction of the anatomy allows for functional outcomes to be limited In these fractures the prosthesis is not (in theory) an alternative to osteosynthesis; in fact in CT2, CT3 and CT4 fractures according to Duparc classification, the choice between osteosynthesis and prosthesis essentially depends on the extent to which the humeral head can be conserved (intact head, dislocated head, sufficiently dense bone), and the age of the patient (with the same fracture, over the age of 60 a «fracture» prosthesis can be discussed, but over the age of 70 an inverse prosthesis would be discussed) However, whichever option was chosen, they both have something in common: tuberosity fixation For osteosynthesis, the existence of markers, due to the presence of the head, and bony stock, also due to the humeral head, allow for very high rates of tuberosity consolidation to be obtained In a conservation sitiuation the risk of necrosis is higher than that of pseudarthrosis of the tuberosities which is not THE problem as with prosthesis placement In fact, in cases with the choice of placing a simple fracture-type humeral prosthesis or even in cases of inverse prosthesis, tuberosity fixation remains a technical challenge, while being a functional necessity The best markers for reconstructing tuberosities In cases where the humeral head is missing, the «ideal» anatomical position for tuberosities is harder to find Therefore, preoperative scanning analysis is essential for all cephalic tuberosity fractures, and the use of an image intensifier during the operation is crucial We feel the delto pectoral approach offers a more overall view to see the best fixation position The «from above» approach gives a feeling of symmetry, but it is less important for placement of the trochin, whilst in front the positioning of the trochiter is possible even if it is difficult In time, the young surgeon will eventually learn that the prosthetic head should disappear at the end of the procedure, covered by the 2 tuberosities, separated either side by the fracture line Everything is placed «around» the prosthetic humeral head If the position of the humeral stem is correct, the tuberosities will also be at the correct height The tuberosity height therefore depends directly on the height of the stem The optimum tuberosity position should be looked at in 3 planes in space, but their respective size, which is variable from one fracture to another, makes it difficult to establish a reproducible technique which would fit every patient and in every situation The distance between the upper centre of the prosthesis and the upper edge of the trochiter must be equal to 5mm but it is difficult during surgery to check this value in so far as the tuberosities align after the stem is fixed A number of studies exist which correlate results for tuberosity consolidation and the height of the stem In the sofcot series, carried out over 175 fractures, there was an error rate of 64% in positioning In a series of 66 patients, Boileau found a rate of 50% for malposition of tuberosities and showed that there was a correlation between an excess of length in the implant and tuberosity malpositioning (1) 2

$Kralinger noted in a group of 167 fractures treated with 5 types of prosthesis, a rate of between 6 and 56% for tuberosity pseudarthrosis (3) In addition to these pseudarthroses, there was also a$

2 More recently, in a retrospective multi-centre analysis of 102 patients, Reuther found 66% with tuberosity pseudarthrosis, with women presenting with an 11 times higher risk of non-consolidation (2) Kralinger noted in a group of 167 fractures treated with 5 types of prosthesis, a rate of between 6 and 56% for tuberosity pseudarthrosis (3) In addition to these pseudarthroses, there was also a malunion in tuberosities (consolidation with a height discrepancy greater than 5mm) in between 8 and 30% of cases With 4 types of prostheses, there were less than half of the cases where the tuberosities consolidated with less than 5mm displacement (3) Therefore tuberosity fixation is primarily linked to the height adjustment of the implant; additionally, this fixation will depend on the type of implant, the metaphyseal load and its shape The bicipital groove and the long biceps are the symmetrical markers which separate the 2 tuberosities However, these can be misleading if the trochin contains part of the groove, where the anatomy is not consistent from one individual to another Therefore the initial stages consist of identifying, isolating and adding threads to each tuberosity The fracture" markers, or anfractuosities of the bony edges are often good markers but are inconsistent in terms of usability The second stage consists of choosing the size of the humeral implant and in positioning it Height adjustment benefits from recent studies on the pectoralis major which have shown that the upper edge of the pectoralis m is situated 55 cm (+or- 05 cm) from the top of the humeral head, an easy marker to find during surgery (4,5) It should not be sectioned too quickly as this marker is difficult to reach from the supero-external route The benefit of an implant such as the Humelock (which locks) is that it allows the prosthetic stem to be fixed at the optimal height using a specific tool Because of the absence of cement, per-operative correction allows real adjustment, as much as necessary, to the stem, while monitoring the height markers visually and with the image intensifier The best tools for reconstructing tuberosities This fracture is the only one that can be fixed with osteosutures Ideally a looped thread can advantageously replace single threads The benefit of the loop is «double» With this being tendon surgery, the quantity of suture is known to be an element of resistance, but a looped thread, known for flexor surgery, allows us to make a series of running knots, which are simple, reproducible and effective, for reliable anchoring of the tuberosities Three systems of 2 looped threads seem valuable to us (figure 1): The first to anchor and draw the tuberosities (figure 2), the next to press them to the implant (figure 3), and the final group of two threads to create a vertical tie-down system Moreover, the design of the stem at the metaphyseal level risks reducing the primary stability, and the tuberosities may slide "turning over with the tension of the suture The idea is, therefore, to have a metaphysis which prevents too much medialisation of the tuberosities whilst also being able to receive grafts (figure 4,5) The presence of a sagittal aileron may lead the surgeon to position a tuberosity on either side, but synthesis to the aileron alone is not sufficient and this aileron may represent an actual barrier to consolidation between the tuberosities Figure 1: Looped thread system from left to right: The first to anchor and draw the tuberosities (in yellow), the next to press them to the implant passing through a hole designed for this (in blue), and the final group of two looped threads to create a vertical tie-down system (in green) 3

Figure 2: Detail of the technique using looped thread (Smartloop ) to anchor and draw the tuberosities: in 1 the looped thread is passed tendon exterior (at the

in 4 the tuberosity can be drawn Figure 3: Detail of the knot technique called lark s head to flatten the tuberosities onto the implant using a sliding looped

running knot which allows temporary fixing (for x-rays, clinical testing) or permanent fixing of the tuberosities to the implant Figure 4: from left to right:

which is sufficiently soft to be moulded, and sufficiently rigid to prevent medialisation of the tuberosities Figure 5: 3 Examples of tuberosity consolidation

3 Figure 2: Detail of the technique using looped thread (Smartloop ) to anchor and draw the tuberosities: in 1 the looped thread is passed tendon exterior (at the limit of bone-tendon), in 2 the thread is passed bone interior ( inside the tuberosity through a drilled hole), in 3 the needle passes back through the loop and in 4 the tuberosity can be drawn Figure 3: Detail of the knot technique called lark s head to flatten the tuberosities onto the implant using a sliding looped thread: you make a lark s head with a looped end (photos on left) in which the other end is passed with the needle (photos on right): you obtain a self-blocking running knot which allows temporary fixing (for x-rays, clinical testing) or permanent fixing of the tuberosities to the implant Figure 4: from left to right: the implant is positioned as well as the cage (Offset Modular System OMS ), an arched monobloc graft, sized to fit the humeral head, will be set inside the cage which is sufficiently soft to be moulded, and sufficiently rigid to prevent medialisation of the tuberosities Figure 5: 3 Examples of tuberosity consolidation after 6 months obtained with the combination of looped thread grafts and OMS In the last photo and in the absence of the OMS cage, the trochiter appears more transparent 4

The series (figure 6-8) An anatomical study of 14 cadavers and a prospective multicentre clinical study of 37 cases were carried out Tuberosity fixation was done with a looped thread (Smartloop,

Constant and Quick dash scores Tuberosity consolidation was re-examined after 6 months (x-ray +or- scan) and correlated to the functionality Post-operative immobilisation was for 1 month, with the

per shoulder) 23/37 patients, of which 3 were men, with an average age of 646 years (49-85) operated on by 10 surgeons were held back as evaluated at 6 months and with an average review at 18 months

4 The series (figure 6-8) An anatomical study of 14 cadavers and a prospective multicentre clinical study of 37 cases were carried out Tuberosity fixation was done with a looped thread (Smartloop, self-blocking running lark s head" knot) on a modular hollow prosthetic metaphysis which can accept grafts (OMS ) The evaluation was done with the measurement of articular range, to calculate the Constant and Quick dash scores Tuberosity consolidation was re-examined after 6 months (x-ray +or- scan) and correlated to the functionality Post-operative immobilisation was for 1 month, with the elbow against the body The tuberosity suturing technique with looped threads was deemed to be reproducible, able to be taught and effective by all surgeons (Anatomical study, use of 5 looped threads per shoulder) 23/37 patients, of which 3 were men, with an average age of 646 years (49-85) operated on by 10 surgeons were held back as evaluated at 6 months and with an average review at 18 months The cohort consists of 10 CT4, and 6 CT2 with a usage 20/23 times of OMS cages, and in all cases autograft and looped threads At 6 months as with the main review, abduction reached 947 (45-130), anterior elevation 102 (45-145), and RE1 29 (0-45) The Quick DASH reached 324 (15-55) and the Constant weighted for age 76 (64-94) The use of OMS with autograft and Smartloop allowed the study to obtain tuberosity consolidation consistently in a good position Figure 6, 7 and 8: 3D reconstruction of a CT4 fracture in a female patient of 64 years, view of consolidation of tuberosities after 6 months and functional results at 6 months 5

$Conclusion The published series report 40 to 66% of malposition or pseudarthrosis of tuberosities In these complex proximal humerus fractures, permanent fixation of tuberosities in the anatomical$ inverse prosthesis positioning (figure 9-11) (7) The technical detail remains osteosuture and the looped thread helps to respect the biomechanical rules of tendon fixation: resistant knot, quantity

inverse prosthesis positioning (figure 9-11) (7) The technical detail remains osteosuture and the looped thread helps to respect the biomechanical rules of tendon fixation: resistant knot, quantity

$surgeon chooses to implant a reverse prosthesis for a 4 part fracture in a patient over 70 years, it is necessary to try and maintain as much tension in the deltoid as possible by having the implant$

5 Conclusion The published series report 40 to 66% of malposition or pseudarthrosis of tuberosities In these complex proximal humerus fractures, permanent fixation of tuberosities in the anatomical position depends on the use of a specific implant (implantable bony autograft) and optimal height adjustment (6) These 2 key points, height markers and tuberosity fixation are also valid for cases of inverse prosthesis positioning (figure 9-11) (7) The technical detail remains osteosuture and the looped thread helps to respect the biomechanical rules of tendon fixation: resistant knot, quantity of thread and distance from support point It is necessary to pursue further study around an optimum fixation and to define the best educational tools to teach this detailed technique Figure 9: If the surgeon chooses to implant a reverse prosthesis for a 4 part fracture in a patient over 70 years, it is necessary to try and maintain as much tension in the deltoid as possible by having the implant sit on top using the marker at the top edge of the pectoralis major is therefore a good means, if persuing the delto-pectoral route, in order to prevent shortening of the limb Figure 10 and 11: Again showing reverse prostheses for fractures, osteosuturing of tuberosities is crucial and allows increased chances of obtaining good functional results in rotation: per-operative view (the supraspinatus must be resected) and x-ray monitoring of 3 different reconstructions 6

6 Bibliographical References 1 Boileau P, Krishnan SG, Tinsi L, Walch G, Coste JS, Molé D Tuberosity malposition and migration: reasons for poor outcomes after hemiarthroplasty for displaced fractures of the proximal humerus J Shoulder Elbow Surg 2002; 11: Reuther F, Mühlhäusler B, Wahl D, Nijs S Functional outcome of shoulder hemiarthroplasty for fractures: A multicentre analysis Injury Kralinger F, Schwaiger R, Wambacher M, Farrell E, Menth-Chiari W, Lajtai G, Hübner C, Resch H Outcome after primary hemiarthroplasty for fracture of the head of the humerus A retrospective multicentre study of 167 patients J Bone Joint Surg Br 2004; 86: Murachovsky J, Ikemoto RY, Nascimento LG, Fujiki EN, Milani C, Warner JJ Pectoralis major tendon reference (PMT): a new method for accurate restoration of humeral length with hemiarthroplasty for fracture J Shoulder Elbow Surg 2006 ;15: Torrens C, Corrales M, Melendo E, Solano A, Rodríguez-Baeza A, Cáceres E The pectoralis major tendon as a reference for restoring humeral length and retroversion with hemiarthroplasty for fracture J Shoulder Elbow Surg 2008 ;17: Lascar T, Vidil A, Rochet S, Hery JY, Daudet JM, Heraud D, Martin JJ, Obert L Results of a series of modular locked-stem humeral prostheses in proximal humeral fractures Anatomical and preliminary clinical multicentre study SECEC Lyon Gallinet D, Adam A, Gasse N, Rochet S, Obert L Improvement in shoulder rotation in complex shoulder fractures treated by reverse shoulder arthroplasty J Shoulder Elbow Surg 2012 sous presse 7

Benefit of an anatomical prosthesis designed specifically for cephalotuberosity fractures.

$Benefit of an anatomical prosthesis designed specifically for cephalotuberosity fractures.$ Benefit of an anatomical prosthesis designed specifically for cephalotuberosity fractures Presentation of technical solutions to improve humerus consolidation and radiological and clinical analyses of