The supinator approach to the lateral elbow: a technique description and literature review

The lateral collateral ligament complex (LCLC) consists of the annular ligament, the radial collateral ligament (RCL), and the lateral ulnar collateral ligament (LUCL). This combined structure is a primary stabilizer against external rotation and varus stress. Acute or chronic insufficiency often leads to posterolateral rotatory instability which has become a more clinically identifiable condition.21O'Driscoll S.W. Bell D.F. Morrey B.F. Posterolateral rotatory instability of the elbow.J Bone Joint Surg Am. 1991; 73: 440-446Google Scholar States of insufficiency may arise from ligament strain, dislocation, fracture dislocation, or inadvertent operative insult.3Bellato E. Castoldi F. Marmotti A. Greco V. Pautasso A. Blonna D. Relationship between the Lateral collateral ligament of the elbow and the Kocher approach: a cadaver study.J Hand Surg Am. 2021; 46: 245.e241-245.e247https://doi.org/10.1016/j.jhsa.2020.09.013Google Scholar Surgical treatment for radial head and neck fractures and complex elbow trauma is increasing due, in part, to improved outcomes.6Chen H.W. Huang S.M. Risk factors of efficacy for patients receiving surgical treatment following terrible triad of the elbow joint: a comparative study.Medicine (Baltimore). 2019; 98: e13836https://doi.org/10.1097/md.0000000000013836Google Scholar,14Heifner J.J. Kolovich G.P. Bolano L.E. Sibley P.A. Gonzalez G.A. Mercer D.M. Revision of failed radial head arthroplasty.Hand (N Y). 2023; 15589447231151434https://doi.org/10.1177/15589447231151434Google Scholar,15Heifner J.J. Rivera Dones A.E. Wells A.L. Mercer D.M. The comparative performance of radial head prostheses in patients younger than and older than 50 years: a systematic review.JSES Rev Rep Tech. 2023; 3: 49-55https://doi.org/10.1016/j.xrrt.2022.09.008Google Scholar,17Klug A. Gramlich Y. Wincheringer D. Hoffmann R. Schmidt-Horlohe K. Epidemiology and treatment of radial head fractures: a database analysis of over 70,000 inpatient cases.J Hand Surg Am. 2021; 46: 27-35https://doi.org/10.1016/j.jhsa.2020.05.029Google Scholar,19Motisi M. Kurowicki J. Berglund D.D. Triplet J.J. Disla S. Niedzielak T. et al.Trends in management of radial head and olecranon fractures.Open Orthop J. 2017; 11: 239-247https://doi.org/10.2174/1874325001711010239Google Scholar,20Mühlenfeld N. Frank J. Lustenberger T. Marzi I. Sander A.L. Epidemiology and treatment of acute elbow dislocations: current concept based on primary surgical ligament repair of unstable simple elbow dislocations.Eur J Trauma Emerg Surg. 2022; 48: 629-636https://doi.org/10.1007/s00068-020-01512-zGoogle Scholar,24Stambulic T. Desai V. Bicknell R. Daneshvar P. Terrible triad injuries are no longer terrible! Functional outcomes of terrible triad injuries: a scoping review.JSES Rev Rep Tech. 2022; 2: 214-218https://doi.org/10.1016/j.xrrt.2022.01.002Google Scholar Consequently, there is increased attention on appropriate management of the LCLC during posterolateral surgical approach to the elbow. The Kocher approach divides the interval between the anconeus and extensor carpi ulnaris (ECU). Subsequent access to the radiocapitellar joint is attained through the ulnar insertion of the LUCL. The Kaplan approach divides the extensor digitorum communis (EDC) and extensor carpi radialis brevis (ECRB). Subsequent access to the radiocapitellar joint is attained through the annular ligament. Noted disadvantages of these approaches are invasion of the ulnar insertion of the LUCL in the Kocher approach and proximity to the posterior interosseous nerve (PIN) in the Kaplan approach. We present the supinator approach for management of elbow trauma which combines the advantages of the Kocher and Kaplan approaches. The supinator approach provides ample exposure of the radial head for fixation or arthroplasty, maintains a safe distance from the PIN, and is likely to avoid the insertional variations of the LUCL. The common extensor tendon originates on the lateral condyle of the humerus and contains superficial and deep compartments of muscles which are innervated by the radial nerve. The anconeus is the most posterior of the superficial compartment with the ECU being adjacent to it. Neighboring the ECU moving anteriorly are the EDC and the extensor carpi radialis longus and brevis. The crista supinatoris (supinator crest) is the attachment point for the ulnar component(s) of the LCLC (Fig. 1). In some cases, this is the annular ligament, with others having additional morphological variants from the humeral origin of the LCLC.11Hackl M. Bercher M. Wegmann K. Müller L.P. Dargel J. Functional anatomy of the lateral collateral ligament of the elbow.Arch Orthop Trauma Surg. 2016; 136: 1031-1037https://doi.org/10.1007/s00402-016-2479-8Google Scholar The cadaveric investigation by Stipp et al25Stipp W.N. Ribeiro F.R. Tenor Junior A.C. Filardi Filho C.S. Molin D.C.D. Petros R.S.B. et al.Anatomical parameters in the lateral ulnar collateral ligament reconstruction: a cadaver study.Rev Bras Ortop. 2013; 48: 52-56https://doi.org/10.1016/j.rboe.2012.05.001Google Scholar quantified the LUCL insertion on the ulna, with 11/13 specimens having an identifiable LUCL insertion and 2/13 having the LUCL conjoined to the annular ligament. The mean distance from the olecranon tip to the distal aspect of the LUCL insertion was 47.6 millimeters (mm) (range: 42.6-55 mm), the mean distance from the articular surface of the radial head to the distal aspect of the LUCL insertion was 22.9 mm (range: 20.2-26.4 mm), and the mean footprint of the LUCL insertion was 9.3 mm (range: 7.5-11 mm). The supinator approach is suitable for bony and ligamentous management accessible on the posterolateral aspect of the elbow. Common cases in which this approach may provide value include radial head arthroplasty and open reduction internal fixation of Mason type III/IV radial head fractures. Case-specific considerations which may lead to a different choice in approach include open injuries, the condition of the surrounding tissues, and certain injury patterns. The patient is positioned supine, and the arm is placed on a hand table with a neutral forearm and elbow flexion of approximately 30 degrees. The following points are marked to identify the boundaries of the incision: (1) the lateral border of the distal humerus, approximately four centimeters (cm) proximal to the lateral epicondyle; (2) the center of the lateral epicondyle; and (3) the posterior border of the ulna, approximately eight cm distal to the olecranon (Fig. 2, a). Subcutaneous dissection should provide ample visualization of the lateral epicondyle proximally (Fig. 2, b). The interval between ECU and anconeus may be identified by the fat stripe which commonly characterizes this demarcation (Fig. 2, b). The deep fascia is incised exposing the septum between the ECU and anconeus (Fig. 2, c, arrow). The interval is opened from the lateral epicondyle of the humerus to the level of the insertion of the anconeus (Fig. 2, d). This portion of the technique is consistent with the commonly performed Kocher approach. The interval between the ECU and supinator is developed to elevate the ECU (Fig. 3, a, arrow). The supinator crest (crista supinatoris) is identified on the ulna which contains the insertion of the supinator and the LUCL (Fig. 3, b, asterisk). In some cases, the LUCL insertion may be consistent with the most prominent supinator tubercle, although this landmark is variable in presence and position.1Anakwenze O.A. Khanna K. Levine W.N. Ahmad C.S. Characterization of the supinator tubercle for lateral ulnar collateral ligament reconstruction.Orthop J Sports Med. 2014; 22325967114530969https://doi.org/10.1177/2325967114530969Google Scholar Often, the surgeon may visually identify the ulna insertion of the LUCL. We identify a point on the supinator crest, approximately two cm distal to the radial head which represents the distal extent of the anterior incision, commonly called the Kaplan interval. In cases of radial head fracture, this point is approximately 3.5 cm distal to the lateral epicondyle and two cm distal to the radial notch or lesser sigmoid cavity. According to the cadaveric work of Stipp et al,25Stipp W.N. Ribeiro F.R. Tenor Junior A.C. Filardi Filho C.S. Molin D.C.D. Petros R.S.B. et al.Anatomical parameters in the lateral ulnar collateral ligament reconstruction: a cadaver study.Rev Bras Ortop. 2013; 48: 52-56https://doi.org/10.1016/j.rboe.2012.05.001Google Scholar this point is likely to be distal to the ulnar insertion of the LUCL. In our experience, measuring approximately 3.5 cm distal to the lateral epicondyle provides a consistent position (Fig. 3, c, dotted line). A transverse mark can be placed across the ECU to delineate the distal extent of the Kaplan interval. An incision, approximately three to four cm in length, is made in the extensor origin to the depth of the bone, from the lateral epicondyle to the radial neck along a trajectory toward Lister's tubercle (Fig. 3, d, dashed line).2Barnes L.F. Lombardi J. Gardner T.R. Strauch R.J. Rosenwasser M.P. Comparison of exposure in the Kaplan versus the Kocher approach in the treatment of radial head fractures.Hand (N Y). 2019; 14: 253-258https://doi.org/10.1177/1558944717745662Google Scholar Importantly, the forearm is pronated to distance the PIN from the process. This incision longitudinally divides the extensor origin, the annular ligament, and the RCL, extending distally to the radial neck. The surgeon will feel the scalpel displace deeper when crossing onto the radial neck. This portion of the technique is consistent with the commonly performed Kaplan approach. Using an inside-out technique, the surgeon transversely releases the ECU at the distal extent of the Kaplan interval (Fig. 4, a and b). This connects the Kaplan interval with the Kocher interval. Retraction of the proximal and distal components of the ECU reveals the underlying capsuloligamentous complex (Fig. 4, c, arrow) and supinator, respectively (Fig. 4, c, Sup). Now the supinator is incised and elevated subperiosteally from the ulna and in continuity from the radius (Fig. 4, d, Sup). It is then retracted anteriorly which provides further protection for the PIN. The extent of supinator release can be determined on a case-by-case basis with certain cases necessitating more distal visualization. If additional exposure to the elbow is required, the anterior capsule can be released from the humerus (Fig. 5, a, arrow). This provides wide access to the proximal radius and lateral elbow (Fig. 5, b). If intact, the humeral origin of the LCLC is preserved. If avulsed from the epicondyle, it is repaired at the end of the case. The supinator approach allows distal extension to the proximal ulna; however, distal access to the radius would require more extensive dissection which may not be preferred. To close, first we reapproximate the capsuloligamentous complex anteriorly at the Kaplan interval. If preferred, the suture can be passed just superficial to the annular ligament to remain extra-articular. In our experience, these tissues are robust and adequately accommodate suture repair. Next, the ECU is repaired, and then the Kocher interval is closed (Fig. 5, c and d). The combined approach provides ample exposure of the radial head and lateral elbow for management of bony and ligamentous injuries. This technique reduces the risk of instability and neurologic insult. The supinator and LUCL are maintained in continuity, and the PIN is adequately protected. The resultant exposure is important for controlling the proximal radius during anatomic arthroplasty preparation and for visualization during fracture fixation. A common criticism of the Kaplan approach is proximity to the PIN during management of the radial head. Cadaveric study has demonstrated that the distance from the PIN to the radial head ranges from seven mm to four cm, depending on the defined point on the radial head.2Barnes L.F. Lombardi J. Gardner T.R. Strauch R.J. Rosenwasser M.P. Comparison of exposure in the Kaplan versus the Kocher approach in the treatment of radial head fractures.Hand (N Y). 2019; 14: 253-258https://doi.org/10.1177/1558944717745662Google Scholar,12Han F. Lim C.T. Lim J.C. Tan B.H. Shen L. Kumar V.P. Deep branch of the radial nerve in lateral surgical approaches to the radial head - a cadaveric study.Orthop Traumatol Surg Res. 2016; 102: 453-458https://doi.org/10.1016/j.otsr.2016.01.023Google Scholar,23Schimizzi A. MacLennan A. Meier K.M. Chia B. Catalano 3rd, L.W. Glickel S.Z. Defining a safe zone of dissection during the extensor digitorum communis splitting approach to the proximal radius and forearm: an anatomic study.J Hand Surg Am. 2009; 34: 1252-1255https://doi.org/10.1016/j.jhsa.2009.04.026Google Scholar Reflection and anterior retraction of the supinator from the proximal radius has been described to further protect the PIN during the Kaplan approach.16Jockel C.R. Zlotolow D.A. Butler R.B. Becker E.H. Extensile surgical exposures of the radius: a comparative anatomic study.J Hand Surg Am. 2013; 38: 745-752https://doi.org/10.1016/j.jhsa.2012.12.029Google Scholar The supinator approach elevates the supinator as a single unit which provides protection for the nerve and improved exposure. A common criticism of the Kocher approach is the potential for violation of the LUCL, which may portend future instability. In a cadaveric study, Bellato et al3Bellato E. Castoldi F. Marmotti A. Greco V. Pautasso A. Blonna D. Relationship between the Lateral collateral ligament of the elbow and the Kocher approach: a cadaver study.J Hand Surg Am. 2021; 46: 245.e241-245.e247https://doi.org/10.1016/j.jhsa.2020.09.013Google Scholar demonstrated that 81% of specimens (13/16) sustained violation of the LUCL during the sharp opening of the Kocher interval. Almost all the specimens had a subsequent positive posterolateral drawer test which indicates the impact of the LUCL on elbow stability. The supinator approach is intended to minimize LUCL risk by performing the capsulotomy distal to the ulnar insertion of the LUCL. To further decrease the risk of LUCL violation, the surgeon may visually confirm the ulnar insertion prior to elevating the supinator. The technique does divide the ECU tendon which may raise the possibility of dysfunction; however, we have not seen evidence of this clinically. Surgical approaches to the lateral elbow have become increasingly relevant as surgical management of complex elbow trauma has increased.17Klug A. Gramlich Y. Wincheringer D. Hoffmann R. Schmidt-Horlohe K. Epidemiology and treatment of radial head fractures: a database analysis of over 70,000 inpatient cases.J Hand Surg Am. 2021; 46: 27-35https://doi.org/10.1016/j.jhsa.2020.05.029Google Scholar Herein we describe the supinator approach to the lateral elbow which minimizes the risk of injury to the LUCL and maintains a safe and comfortable distance from the PIN. Across a spectrum of investigations, the LUCL has demonstrated inconsistent presence and character. Morrey and An18Morrey B.F. An K.N. Functional anatomy of the ligaments of the elbow.Clin Orthop Relat Res. 1985; 201: 84-90Google Scholar reported that the LUCL is a confluence of fibers from the annular ligament and RCL which insert onto the supinator crest. O'Driscoll et al22O'Driscoll S.W. King G.J. Jupiter J.B. Hotchkiss R.N. Morrey B.F. The unstable elbow.Instr Course Lect. 2001; 50: 89-102Google Scholar described deficiency of the LUCL as the "essential lesion" in posterolateral rotatory instability of the elbow. Hackl et al11Hackl M. Bercher M. Wegmann K. Müller L.P. Dargel J. Functional anatomy of the lateral collateral ligament of the elbow.Arch Orthop Trauma Surg. 2016; 136: 1031-1037https://doi.org/10.1007/s00402-016-2479-8Google Scholar proposed a morphologic classification of the LUCL with type I having a bilobed insertion, type II jointly inserting with the annular ligament, and type III coalescing into the annular ligament. The novel findings of Fukai et al10Fukai A. Nimura A. Tsutsumi M. Fujishiro H. Fujita K. Imatani J. et al.Lateral ulnar collateral ligament of the elbow joint: reconsideration of anatomy in terms of connection with surrounding fibrous structures.J Bone Joint Surg Am. 2022; 104: 1370-1379https://doi.org/10.2106/jbjs.21.01406Google Scholar indicate that the structure termed the LUCL may be more accurately described as a capsule-aponeurotic membrane, having extensive continuity with neighboring tissues. Although the qualitative specifics remain unclear, there is general agreement on the important stabilizing contribution of the LUCL. A 40-year-old female with a 39 kg/m2 body mass index sustained an elbow injury following a fall from standing height. Radiographic investigation revealed a Mason IV fracture of the radial head (Fig. 6, a). A computed tomography scan was performed to better understand the fracture characteristics and facilitate the surgical plan (Fig. 6, b and c). The supinator approach was used to provide wide exposure of the radial head and preserve the ulnar attachment of the LUCL. The radial head was deemed irreparable, and an arthroplasty was performed (Fig. 6, d and e). Postoperatively, the arm remained in a splint for five days, and then progressive elbow range of motion was initiated. At 6 months postoperatively, the patient had satisfactory function. There was no elbow instability suggestive of violation of the ulnar attachment of the LUCL or neurologic symptoms suggestive of PIN insult. Patient consent was given for reporting of the case details. Common approaches to the radial head are often described and compared. Furthermore, novel approaches to the radial head have been proposed with unique benefits. The comparative investigation by Barnes et al2Barnes L.F. Lombardi J. Gardner T.R. Strauch R.J. Rosenwasser M.P. Comparison of exposure in the Kaplan versus the Kocher approach in the treatment of radial head fractures.Hand (N Y). 2019; 14: 253-258https://doi.org/10.1177/1558944717745662Google Scholar demonstrated that the Kaplan approach (EDC/ECRB) provides significantly greater visualization of the proximal radius compared to the Kocher approach. Cutler et al7Cutler H.S. Kelly D. Gross B. Rinehart D. Hull B.R. Sanders D. et al.Increased articular exposure of the lateral elbow joint with the anconeus approach compared to the Kocher approach: a cadaver study.Arch Orthop Trauma Surg. 2021; 141: 917-923https://doi.org/10.1007/s00402-020-03489-1Google Scholar concluded that an anconeus reflecting approach from the ulna provided a greater surface area of radiocapitellar and ulnohumeral articular exposure compared to the Kaplan approach. Criticism of the common posterolateral approaches focuses on the limited exposure of surrounding structures and mobilization of the radial head. Touloupakis et al26Touloupakis G. Biancardi E. Ghirardelli S. Antonini G. Crippa C. Detachment of extensor carpi ulnaris and anterior branches of the radial collateral ligament from the epicondyle: a modification of kocher lateral approach for the treatment of radial head fractures.Joints. 2019; 7: 31-36https://doi.org/10.1055/s-0039-1697613Google Scholar described a modified version of the Kocher approach with detachment of the anterior branches of the RCL from the epicondyle, and preservation of the LUCL. The authors noted that proximal detachment of the ligament allows lateral dislocation of the radial head, improving visualization of the anteromedial surface of the radial head. Charalambous et al5Charalambous C.P. Stanley J.K. Siddique I. Powell E. Alvi F. Gagey O. The Wrightington approach to the radial head: biomechanical comparison with the posterolateral approach.J Hand Surg Am. 2007; 32: 1576-1582https://doi.org/10.1016/j.jhsa.2007.08.009Google Scholar described an osteotomy of the ulnar insertion of the LUCL which provided greater stability compared to a traditional posterolateral approach which violated the LUCL. The authors postulated that the LUCL may provide a posterolateral buttress which stabilizes the radial head during varus loading. Desouky et al9Desouky A.M. Atiyya A.N. Elbishbishi M. Sawy M.M.E. A modified trans-anconeus approach to facilitate fixation of a posterior radial head fracture: a cadaveric feasibility study.Anat Cell Biol. 2023; 56: 39-45https://doi.org/10.5115/acb.22.201Google Scholar presented a transanconeus approach with distal extension to manage posteromedial radial head fractures. Han et al13Han F. Teo A.Q. Lim J.C. Ruben M. Tan B.H. Kumar V.P. Outcomes using the extensor digitorum communis splitting approach for the treatment of radial head fractures.J Shoulder Elbow Surg. 2016; 25: 276-282https://doi.org/10.1016/j.jse.2015.09.030Google Scholar reported an EDC splitting approach with purported advantage of improved anterior visualization and reduced iatrogenic-induced instability which may occur using the Kocher approach. Berdusco et al4Berdusco R. Louati H. Desloges W. Papp S.R. Pollock J.W. Lateral elbow exposures: the extensor digitorum communis split compared with the Kocher approach.JBJS Essent Surg Tech. 2015; 5: e30https://doi.org/10.2106/jbjs.St.N.00048Google Scholar recommended the EDC splitting approach for radial head fracture treatment due to the frequency of involvement of the anterior radial head. The same group quantified a greater visualization of the proximal radius in the EDC split approach compared to the modified Kocher approach.8Desloges W. Louati H. Papp S.R. Pollock J.W. Objective analysis of lateral elbow exposure with the extensor digitorum communis split compared with the Kocher interval.J Bone Joint Surg Am. 2014; 96: 387-393https://doi.org/10.2106/jbjs.M.00001Google Scholar In totality, the literature contains comparative reports and myriad approaches to the radial head intended to maximize exposure and avoid violation of surrounding structures. We present the supinator approach to the lateral elbow which combines the advantages of the Kaplan and Kocher approaches. This technique maintains a safe distance from the PIN and is likely to avoid the insertional variations of the LUCL. In our experience, the approach is reproducible, provides ample exposure of the radial head and lateral elbow, and reduces the risk of instability and neurologic insult. Furthermore, the extent of supinator release can be determined on a case-by-case basis with certain cases necessitating a more distal visualization.