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Triceps Split and Snip approach to the elbow: surgical technique and biomechanical evaluation Peter C. Poon, Supileo Foliaki, Simon W. Young and David Eisenhauer Department of Orthopaedic Surgery, North Shore Hospital, North Shore City, New Zealand
Key words elbow approach, triceps friendly, Triceps Split and Snip. Correspondence Peter C. Poon, Department of Orthopaedic Surgery, North Shore Hospital, Private Bag 93 503, Takapuna, North Shore City 0740, New Zealand. Email:
[email protected] P. C. Poon FRACS; S. Foliaki MBChB; S. W. Young FRACS; D. Eisenhauer MD. Accepted for publication 13 February 2013. doi: 10.1111/ans.12131
Abstract Background: A number of posterior approaches to the elbow have been described, which vary in the quality of the exposure and morbidity to the triceps mechanism. We describe an adapted technique, the Triceps Split and Snip, which may offer improved surgical exposure during posterior approach to the elbow. We aimed to compare the strength of the triceps repair in this approach to a more traditional approach described by Bryan and Morrey. Methods: Sixteen pairs of cadaveric elbows were randomized by surgical group and operative side. The Triceps Split and Snip and Bryan-Morrey approaches were each performed on eight specimens, followed by repair of the triceps; the contralateral elbow served as the control. The specimens were then mounted on a material testing system and a constant velocity elongation was applied. Results: The mean load to failure for the Bryan-Morrey group was 421N (range 349–536N). While the Triceps Split and Snip group was 388N (range 267–550N). The percentage ultimate strength loss was 40% for both groups. No significant difference was found in comparing the mean load to failure between the Triceps Split and Snip approach and the Bryan-Morrey approach. Conclusions: The Triceps Split and Snip approach is a technically simple approach to perform and repair, and provides excellent exposure of the elbow and distal humerus. The tensile strength of the triceps repair following this approach is equivalent to that of the Bryan-Morrey approach.
Introduction An ideal posterior approach to the elbow should be simple and versatile. It should provide excellent exposure for a variety of technically demanding surgical procedures; including primary and revision elbow arthroplasty, fracture fixation and other conditions of the elbow. It should be easy to repair and not complicate postoperative rehabilitation by the need to protect the triceps mechanism. Currently, no such ‘ideal’ approach exists, although many surgical approaches for elbow arthroplasty have been described. The ‘V-Y’ approach divides the triceps tendon in a V-Y turndown fashion.1–6 Gschwend described splitting the triceps tendon followed by subperiosteal elevation of the triceps insertion,7 which has also been modified to include a fleck osteotomy during the elevation.8 The Bryan-Morrey approach consists of complete subperiosteal elevation of the triceps from medial to lateral,9 and finally ‘Triceps on’ approaches aim to leave the triceps insertion intact.10–12 All elbow approaches balance quality of surgical exposure against degree of disruption to the triceps mechanism. The V-Y provides
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excellent exposure, and can be used in primary or revision elbow arthroplasty, but postoperative rehabilitation is restricted by the need to protect the triceps and a reported rate of triceps morbidity of up to 29%.13,14 The Gschwend (triceps split and elevation) approach is also simple in theory; however, splitting the triceps tendon and elevating its insertion in two halves must be meticulously performed, and transosseous repair of the triceps tendon can be difficult. Rehabilitation is also complicated by the need to protect the triceps, and triceps morbidity has been reported to be up to 11%.13,14 Of all the posterior approaches to the elbow, the ‘Triceps-On’ approach offers the least morbidity to the triceps mechanism. No repair of the triceps insertion is required when performing a Triceps-On approach, and there is no need to protect the extensor mechanism during rehabilitation. However, dislocating the elbow joint with the triceps insertion intact can be difficult, particularly in a very stiff joint or if the triceps muscle is very bulky. Thus, exposure can be suboptimal, especially to surgeons who do not perform a large volume of elbow arthroplasty. Finally, the complete medial-lateral triceps elevation of the Bryan-Morrey is time consuming,15 and as with the Gschwend © 2013 The Authors ANZ Journal of Surgery © 2013 Royal Australasian College of Surgeons
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Fig. 1. Left elbow. Posterior skin incision, with full thickness skin flaps elevated and the ulna nerve identified. Midline split of the triceps tendon proximally, extending distally in a lateral ‘para-olecranon’ manner. A 3–5 mm cuff of deep fascia is left on the proximal ulna for a subsequent side-to-side repair.
approach transosseous repair of the triceps tendon is technically demanding and requires protection during postoperative rehabilitation. However, it provides excellent exposure, and was recently shown in a cadaveric study to have the strongest repair of three common posterior approaches to the elbow.16 We describe a modified surgical approach to the elbow, the Triceps Split and Snip approach, which provides excellent exposure and aims to minimize triceps morbidity. We aimed to compare the strength of the triceps repair in this approach to the Bryan-Morrey using biomechanical evaluation in cadavers.
Surgical technique
Figs 2 and 3. Left elbow, a Snip is being added to the Triceps Split for a complete, unobstructed view of the distal humerus and elbow.
For primary elbow arthroplasty, the patient is positioned in the lateral decubitus position, with the operative extremity suspended over a bolster. A posterior midline skin incision is made, curving medially around the tip of the olecranon. Full thickness skin flaps are elevated, and the ulna nerve is identified, mobilized and protected. The triceps tendon is split in its midline, and extending distally, the incision is curved around the lateral aspect of the olecranon and then down along the lateral border of the proximal ulna (Fig. 1). In extending the incision distally, it is important to leave a 3 to 5 millimetre cuff of triceps tendon and deep fascia on the lateral aspect of the proximal ulna, for subsequent side-to-side repair. At this stage, the medial portion of the triceps tendon remains intact. The lateral portion of the triceps is subperiosteally mobilized, and the lateral collateral ligament is detached subperiosteally from the lateral epicondyle. A tag suture is placed in the lateral collateral ligament, marking it for subsequent repair if indicated. Next, the medial collateral ligament is likewise detached subperiosteally. Through the window of the triceps split, an anterior capsular release
from the distal humerus is performed using a periosteal elevator. Next, the medial portion of the triceps tendon is subperiosteally mobilized from the posterior surface of the distal humerus. The joint can then be dislocated medially, with the remaining medial portion of the triceps tendon intact. It is easier to dislocate the elbow joint around an intact medial portion (50%) of the triceps, than when the entire bulk of the muscle is intact. If there is any difficulty dislocating the elbow joint, we perform a snip of the medial portion of the triceps tendon, leaving a 1 to 2 centimetre cuff of tendon proximal to the tip of the olecranon, for subsequent end-to-end repair. This Triceps snip and split approach allows a full, unobstructed view of the elbow joint (Figs 2,3). Following the procedure, the triceps split is repaired side-to-side with a series of interrupted sutures. If a snip was utilized, an endto-end repair is carried out with interrupted sutures (Fig. 4). The ulna nerve is transposed if it is subluxating and the skin is closed in
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layers. Sterile dressings are applied and the elbow is splinted in extension for 1 week to allow wound swelling to settle. Early mobilization is then initiated.
Materials and methods
Fig. 4. End-to-end repair of the Snip, with side-to-side repair of the Triceps Split. In this case example, dual plates are seen as the approach was utilized for an intra-articular fracture of the distal humerus.
Sixteen pairs of embalmed cadaveric elbows were randomized using numbered envelopes to the Triceps Split and Snip or Bryan-Morrey approach. The side was also randomized with the contralateral elbow serving as a standardized control. Following the BryanMorrey approach, the triceps mechanism was repaired using the method described by Guerroudj;16 Number 5 Ticron suture was passed through the triceps tendon as a tendon grasping suture, two crossed transosseous drill holes were made in the olecranon, and the two suture ends were passed through the bone. They were then tied on the dorsum of the ulna. The remaining triceps periosteal insertion was repaired to the deep fascia of the medial forearm using a series of interrupted 5 Ticron sutures. Following the Triceps Split and Snip approach, the triceps was repaired with interrupted five Ticron sutures as well. First, an end-to-end repair was performed on the triceps snip component and then the triceps split was repaired in a side-to-side fashion. No transosseous sutures were used. The specimens were then evaluated using the Instron material testing system (Instron, Norwood, MA, USA) (Fig. 5). The cadaveric elbows were mounted on the testing system in a position of extension. Proximally and distally, the specimens were fixed with transosseous fixation rods, through the humerus and ulna, respectively. The triceps muscle belly was fixed on to the humerus using a series of four cerclage clamps. The Instron material testing system was used to apply a constant load of 1 kN load head, producing an elongation rate of 2.5 millimetres/minute. The triceps mechanism was then loaded to failure on the surgical side and on the contralateral control side. The absolute values of the point of load to failure were recorded in Newtons. The relative strength of the surgical side compared to the contralateral control side was then calculated as a percentage; ultimate strength loss (USL) was calculated for each operated specimen from ultimate tensile strength (UTS) following the method of Guerroudj,16
USL % = ( UTSsurgery − UTScontrol ) ∗100 UTScontrol UTScontrol and UTSsurgery are the UTS of the contralateral control tendon and UTS of the operated tendon, respectively, in one pair of specimens.
Statistical method The results consisted of continuous variables and the means of the two groups were compared using Mann–Whitney’s U-test. A P-value of less than 0.05 was considered to be significant. Based on previous literature showing a mean load to failure for a BryanMorrey of 701N,16 in order to detect a 20% difference in load to failure for the Triceps snip and split approach a sample size of eight was required. Fig. 5. Instron material testing system, with a Steinmann pin placed through the humerus proximally and the ulna distally. The musculotendinous junction was re-enforced and fixated to the shaft of the humerus using four cerclage clamps.
Results The mean load to failure in the control elbows for the Bryan-Morrey surgical approach group was 731N, and in the Triceps Split and Snip © 2013 The Authors ANZ Journal of Surgery © 2013 Royal Australasian College of Surgeons
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Table 1 Load to failure (Newtons) and strain of the Bryan-Morrey group and the Triceps Split and Snip group Bryan-Morrey Mean Load Control Repair Difference % ultimate strength loss (95% Confidence interval) Strain Control Repair Difference 95% Confidence interval
731 421 310 -40 (-54 to -26) 5.2 3.9 -1.3 (-3.8–1.3)
Triceps Split and Snip
Median
722 400 342 -49
4 3.8 -0.6
Range
Mean
Median
Range
P-value
500–1010 349–536 100–566 -56 to -20
702 388 314 -40 (-58 to -23)
777 358 373 -42
333–1025 267–550 24–509 -66 to -7
0.95 0.41 0.85 0.95
1.7–10.6 1.9–6.2 -6.8–2.2
4.3 3.5 -0.7 (-1.9–0.5)
5.2 3.8 -0.6
1.6–7.1 1.5–6.0 -3.3–0.6
0.57 0.75 0.65
Fig. 6. Site of triceps mechanism rupture following the Bryan-Morrey approach was at the insertion. The periosteal insertion was the weakest point.
Fig. 7. Site of the triceps mechanism rupture following the Triceps Split and Snip was just above the triceps snip and just below the musculotendinous junction.
control group was 702N. The mean load to failure for the BryanMorrey surgical approach group was 421N (range 349–536N), and for the Triceps Split and Snip group was 388N (267–550N, P = 0.51) (Table 1). The percentage of ultimate strength loss in comparison to the contralateral side was identical at 40% for both the BryanMorrey approach group and the Triceps Split and Snip approach group (P = 0.98). The anatomical location at the point of failure of the triceps mechanisms differed between the two approaches. In the BryanMorrey group, rupture occurred at the triceps insertion when loaded to failure in all cases (Fig. 6), suggesting the periosteal insertion was the weak point of the triceps mechanism. Following a simulated Triceps Split and Snip approach, rupture occurred just above the triceps snip and just below the musculotendinous junction upon
failure (Fig. 7). This location is very similar to that observed in the contralateral control specimens. The repair of the Triceps Snip remained intact on all specimens. On close inspection, when the triceps mechanism began to rupture, the suture holes just above the snip were seen to elongate and propagate into a full rupture. This may have been what caused the relative weakening of the extensor mechanism compared to the contralateral control elbow.
© 2013 The Authors ANZ Journal of Surgery © 2013 Royal Australasian College of Surgeons
Discussion Surgical exposure of the elbow joint must balance quality of exposure against morbidity to the triceps mechanism. The Triceps Split and Snip approach provides exposure comparable to the BryanMorrey approach, but is quicker to perform as subperiosteal
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elevation is not required. It is also simpler to repair as no transosseous sutures are used. Our study shows that the strength of the triceps repair in the two approaches appears to be equivalent. The strength of the repair in the Triceps Split and Snip approach is supplemented by the fact that the lateral triceps expansion remains in continuity with the distal fascia. This expansion of the triceps insertion was recently described by Keener,17 and continues into the fascia over the anconeus and the deep fascia of the forearm. As this lateral portion of the triceps tendon is in continuity with the fascia of the forearm, the repair following the Triceps Split and Snip approach is protected, and in our practice, we allow early active motion following surgery. This is analogous to the medial parapatellar approach in the knee, which can be supplemented with a quadriceps snip to aid exposure with minimal additional morbidity.18 We perform a lateral para-olecranon approach, which is supplemented with a medial triceps snip. We chose to compare the Triceps Split and Snip with the approach described by Bryan-Morrey not only because it is a well-known posterior approach to the elbow, but also because it was recently shown to be the strongest of three commonly used techniques for management of the triceps mechanism. Guerroudj16 analysed triceps repair strength in a cadaver study and found the ultimate strength in comparison to the contralateral side to be 43% for the Bryan-Morrey approach versus 27 and 22% in the Gschwend and V-Y approaches, respectively. While the Triceps-On approach has not been tested biomechanically, it is likely to be the strongest repair as the main portion of the triceps mechanism remains intact. However, this approach is difficult from the standpoint of visualization and instrumentation, particularly for those who do not perform a large volume of elbow arthroplasty. The Triceps Split and Snip approach offers improved exposure; and like the Triceps-On approach, early mobilization can be instituted as the lateral expansion of the triceps mechanism remains intact. Additionally, the size of the ‘snip’ can be varied depending on the exposure required, and indeed in many clinical situations may be omitted completely. There are a number of limitations to this study. Firstly, the direct method of assessing strength used in this study, while commonly used in the literature,16 is distinct to the low load/high repetition of clinical rehabilitation post-elbow surgery. Secondly, we used embalmed rather than fresh frozen cadaveric elbows, which may alter the absolute tensile strength values obtained. However, as we used the contralateral elbow as a standardized control, comparisons between the two approaches remain valid. Our finding of a 40% relative strength for the Bryan-Morrey approach supports this, as it is very similar to the 43% seen in a previous study utilizing fresh frozen cadavers.16 In conclusion, we describe a modified approach to the elbow, the Triceps Split and Snip. The approach is simple to perform, provides excellent exposure and is easily repaired. Our study has validated the strength of the triceps repair following this approach, and we rec-
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ommend this as an addition to the surgeon’s armamentarium for exposure of the elbow and distal humerus.
Acknowledgements Department of Anatomy, Auckland Medical School, for the provision of cadaver specimens. Department of Bioengineering, Auckland University, for technical assistance with the biomechanical testing of cadaver specimens.
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