Clinical Outcomes Following Reduction and Pinning of Lesser Arc Injuries Without Repair of the Scapholunate Interosseous Ligament

1. Acknowledgements

The copyright of this thesis vests in the author. No quotation from it or information derived from it is to be published without full acknowledgement of the source. The thesis is to be used for private study or noncommercial research purposes only.
Published by the University of Cape Town (UCT) in terms of the non-exclusive license granted to UCT by the author.

DECLARATION
I, Thomas Laurence Hilton, hereby declare that the work on which this dissertation is based is my original work and that neither the whole work nor any part of it has been, is being, or is to be submitted for another degree in this or any other university.
I empower the university to reproduce for the purpose of research either the whole or any portion of the contents in any manner whatsoever.

Methods
Dislocations were reduced anatomically and held with buried k-wires which were removed at 6 weeks with no specific rehabilitation protocol observed. Subjective assessment included MAYO wrist scoring system, wrist range of movement, instability and grip strength testing. Radiological measurements included scapholunate distance, scapholunate angle, radiolunate angle and osteoarthritis.

Results
10 male patients, median age of 35, were followed-up for a median of 22 months. 7 patients underwent a closed reduction and anatomical pinning while 3 underwent open reduction due to unachievable reduction by closed means. All of these patients presented at a median of 14 days after the injury occurred. None of the patients had their scapholunate ligaments repaired or reconstructed. MAYO scores included, 3 excellent scores, 2 good scores and 5 fair scores. Instability was found clinically in 1 asymptomatic patient who had a positive Watson shift test.
Radiological scores include a median scapholunate distance of 2mm, a scapholunate angle of 70° and a radiolunate angle of 15°. Osteoarthritis was found in 2 patients, all of whom were asymptomatic.

Current recommendations in the literature are that PLDs should be reduced via
an open surgical technique with repair of the SLIL and percutaneous pinning.
However the results of this treatment strategy are not optimal and do not confer uniformly good results. We propose a closed anatomical reduction and percutaneous pinning of the PLD. Our study shows that the majority of patients will demonstrate good function and pain scores when managed this way. A smaller number of these injured wrists will go on to develop instability. However the advantage of our method over the current recommendations is that when this happens the reconstruction of the SLIL will be made easier through a naïve surgical field.

Conclusion
We recommend the closed reduction and anatomical pinning of a purely ligamentous lesser arc injury. This treatment strategy yields good results at medium term follow-up and preserves the option for the reconstruction of the scapholunate interosseous ligament should instability develop.

Acknowledgements
To my wife and family for their support and patience.
To all the lecturers of the Department of Orthopaedics at UCT for their enthusiastic approach to practicing and teaching Orthopaedics.
To To my co-author Dr David Chivers who helped greatly in the initial conceptualization and protocol phase of this project as well as assisting with the challenging data collection, I give thanks.
I would like to thank Dr Michael Solomons who was invaluable during the review of the manuscript prior to submission for publication.
I would also like to acknowledge the assistance given to me by Henri Carrera in supervising the statistical analysis of this work.      Placement. Figure 1a shows an anterior-posterior x-ray of the wrist joint. Figure   1b shows a lateral x-ray of the wrist joint.

a. Objectives
The objectives of this literature review are to: • Clarify the definition, epidemiology, aetiology, patho-anatomy, clinical and radiographic features and natural history of perilunate dislocations.
• To research the treatment options used and critically analyse the literature reporting outcomes of these described methods • To identify areas of potential future research

b. Methods
Google Scholar and Pubmed internet search engines were used to search online databases.
The key strings 'perilunate dislocations', 'wrist instability', 'lesser arc injuries' and 'scapholunate interosseous ligament' were used to search for articles. Google Scholar produced 2830 results and Pubmed 932 articles. All articles not written in English and prior to 1960 were excluded. Of the remainder 39 were selected based on their relevance. Review articles on the subject were analysed and their references were researched.
The chapter on wrist instability in Green's Operative Hand Surgery was reviewed and the relevant references researched. All relevant articles were obtained from the University of Cape Town library either in hardcopy form or in digital format.

Quality of evidence
The evidence on the topic is limited to case studies and small case series due to the rarity of this injury. Any larger studies included a heterogeneous group of patients with similar injuries from which the lesser arc data was extracted. All the studies can be classified as levels IV and V of evidence and there is no higher level of evidence available on the topic.

d. Wrist anatomy and biomechanics
Carpal anatomy It is crucial to understand carpal anatomy when treating wrist injuries. 'The human wrist is a product of millions of years of evolutionary adaptation that has culminated in a specialised unit that is able to accurately position the hand in a nearly hemispherical arc of movement. [1] The carpus consists of 8 carpal bones that are arranged in 2 rows. The distal row of the carpus, which includes the trapezium, trapezoid, capitate and hamate is relatively immobile due to strong intercarpal ligaments and its close approximation to the index and middle finger metacarpals. This row is considered part of the fixed hand unit and moves in response to the extrinsic musculotendinous forces created in the forearm.' [1] The proximal row of the carpus includes the scaphoid, lunate and triquetrum, it is more mobile than its distal counterpart and accounts for most of wrist movement. There are no muscular or tendinous insertions on the proximal row thus making this an intercalated segment between the distal row and the radius. [1] The ligaments of the wrist are categorised as intra-capsular or intra-articular. They can be further sub-divided into intrinsic or extrinsic ligaments. Extrinsic ligaments originate from the radius or ulna and insert onto the carpus. Intrinsic ligaments connect 2 carpal bones. [2] The SLIL is an intrinsic ligament and connects the scaphoid to the lunate at the dorsal, proximal and volar margins of the articulating surfaces making it C-shaped. Its  ligaments. [2] Wrist mechanics -Stability and movement

Stability
The SLIL is considered the primary stabiliser of the wrist and is supported by an envelope of secondary stabilisers which are orientated obliquely to the axis of wrist movement activities. However when the SLIL becomes incompetent movement between the two bones increases, which puts strain on the secondary stabilisers. Over time these ligaments undergo attritional wear which is thought to be the cause for dorsal intercalated instability of the wrist. [1] Wrist instability Scapholunate wrist instability is regarded as a spectrum of injury whose current definition is of a wrist that exhibits symptomatic dysfunction, is unable to bear loads and does not demonstrate normal kinematics throughout the complex arc of wrist motion. [1] e. Pathomechanics & classification of PLD's These injuries affect both soft tissues and bony elements of the wrist and present in 2 common patterns. The degree, duration and direction of the force dictates whether the injury will be a purely ligamentous, i.e. lesser arc injury or PLD, or whether it will be associated with a fracture, i.e. greater arc injury. Greater arc injuries are the more common injury pattern occurring up to 65% of the time.
The defining characteristic of these injuries is dorsal dislocation of the capitate head from the lunate concavity which remains in its anatomical position in the lunate fossa of the radius. A volar lunate dislocation is the final stage of a perilunate injury, the capitate has reduced from its dorsally dislocated position to become collinear with the radius thereby dislocating the lunate in the carpus. The pathomechanics are of a specific loading pattern which has been described my Mayfield. The pattern is of a radial sided force exerted to a hyperextended wrist with a degree of ulnar deviation and intercarpal supination. [3] Mayfield was able to describe 4 stages of progressive ligamentous disruption.

f. PLD's as a clinical entity
PLD's almost always result from high energy trauma such as car accidents, falls from a height and some sporting activities. They occur most commonly in men with an average age of 30. [2,5] Patients often have associated injuries, due to the high energy nature of the injury, which often take priority in the treatment ladder. The direction is dorsal 97% of the time and 10% are open. [3,6] On clinical examination a high index of suspicion needs to be maintained to correctly diagnose an acute isolated scapholunate dislocation. Tenderness is present but diffuse and often inhibits further testing. Soft tissue swelling is often severe and precludes the accurate diagnosis of a wrist effusion which in itself indicates a severe intra-articular wrist injury.
Neurovascular examination is usually normal except in severe injuries in which case the median nerve will be involved especially in lunate dislocations.
As much as 25% of these injuries can be missed on initial presentation and should this be the case patients may present with a sub-acute injury (1-6 weeks). [1-3, 6, 7] In this scenario they may complain of painful popping or clicking with wrist movement,

Measurement of angles if scapholunate dissociation is suspected
Measurement of intercarpal angles on static films is difficult with wide inter-observer variability and is therefore not routinely done or an approximation is performed. These lines are used to indicated instability either in the dorsal or volar plane.
One of these angles is the radiolunate angle which is a perpendicular line drawn from the lunate tangent. This angle determines the lunate posture in the sagittal plane. A radiolunate angle of more than 15 degrees in the volar direction is indicative of volar intercalated segment instability (VISI) and in the dorsal plane is indicative of dorsal intercalated segment instability (DISI). A DISI is far more common in the scenario of a SLIL disruption.

Figure 10: Picture to demonstrate radiolunate angle[8] (Internet)
The scapholunate angle is measured between the scaphoid tangent and the perpendicular to the lunate tangent. It normally measures 46 degrees (range 30 -60). If above 70° it is suggestive of a flexed scaphoid or rotatory subluxation. Ancillary studies These studies are used to confirm a clinically suspected diagnosis of SLIL dissociation and should not be used in isolation. Treatment is still based on patient's symptoms and clinical examination. This is due to their relatively higher rate of false positives. Wrist arthrography which was previously deemed to be the most sensitive test for injury has been supplanted MRI or CT arthrography. However both arthrography and MRI give only anatomic evaluations without any functional information.
To better assess function status of the wrist cineradiology or simple fluoroscopy can be helpful in demonstrating abnormal wrist kinematics. However the gold standard to evaluate both anatomical, interosseous and extrinsic ligaments, and functional status is wrist arthroscopy. The ability to pass the arthroscope from the radiocarpal joint into the midcarpal joint through the scapholunate interval is termed the drive-through sign. This sign indicates a complete tear of the scapholunate ligament and laxity of its secondary stabilisers.

Conservative treatment of wrist instability
Historically PLDs were treated with closed reduction and casting in plaster of Paris however the results of this treatment were less than satisfactory. [9,10]  There is no debate that accurate reduction of the carpus is imperative to good long term outcome. [3] According to Adkison a more conservative method of treatment (plaster of paris) has high failure rates due loss of reduction of the carpus with time once the temporary fixation had been removed. [10] Failure to maintain reduction caused significant structural collapse and accelerated carpal osteoarthritis. From this the conclusion was that these injuries are inherently unstable, and reduction cannot be maintained with closed methods alone. [9,10,12] It is this premise that has driven the more aggressive treatment of these injuries with open surgery being advocated to ensure a perfectly anatomical reduction, seeing is believing so to speak. There is also no debate as to the importance of the SLIL in normal wrist biomechanics. [1,[13][14][15] It has been described as the cruciate of the wrist and it has been proposed that its integrity is essential for normal wrist movement and stability. [1] It this stands to reason that its rupture will result in abnormal wrist biomechanics which will lead to instability of the carpus which in turn will result in accelerated post traumatic osteoarthritis. [3] The clinical manifestation of this will be pain, stiffness and weakness. pinning to open reduction and pinning. In this study they found no statistical difference in outcome between these two groups. [9] In neither of the above papers did any of the patients with casting alone do well. The open reduction and pinning group had a 65% good outcome, with any poor outcomes in this group attributed to scaphoid injuries and their resulting non-unions. [

Part B: Manuscript in article format a. Journal information
Article submitted to: The  No financial support was received for this study or publication including grants or pharmaceutical company support.
There was no commercial or financial involvement that might present an appearance of a conflict of interest related to the submission.
There was no sponsorship of the research that would prevent the authors publishing both positive and negative results or forbids the authors from publishing this research without the prior approval of the sponsor.

Funding Statement
This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.

Informed consent
Informed consent was taken from the patients prior to enrolment in the study and documented with the signing of a consent form.

c. Abstract Introduction
Purely ligamentous lesser arc, Mayfield grade 3 and 4, injuries are uncommon.

Methods
Dislocations were reduced anatomically and held with buried k-wires which were removed at 6 weeks with no specific rehabilitation protocol observed. Subjective assessment included MAYO wrist scoring system, wrist range of movement, instability and grip strength testing. Radiological measurements included scapholunate distance, scapholunate angle, radiolunate angle and osteoarthritis.

Results
10 male patients, median age of 35, were followed-up for a median of 22 months. instability. 11 We feel that an open reduction, internal fixation and repair of the SLIL is unnecessary in the acute stage of this injury. We hypothesize that a less invasive approach to the early treatment of these injuries will have good mediumterm results in the majority of patients while minimising further trauma and still preserve the ability to perform more extensive surgery should instability develop. If closed reduction was not possible emergently, the patient was splinted and the reduction and definitive surgery was performed the following day by the senior hand surgeon on duty. We found this only to be the case in injuries that presented late to the unit.

Method of reduction
Perilunate and lunate dislocations were reduced closed using Tavernier's manoeuvre 12 . The technique used by the unit to perform an accurate and anatomic closed reduction was by one of two ways. If 2 surgeons were present, a percutaneous joystick manoeuvre, as described in Greens Operative Hand Surgery 13 , was used. If a single surgeon was present the lunate was manipulated to be co-linear with the capitate and radius and temporarily held with a smooth 1mm or 1.2mm K-wire from the radius to the lunate. The wrist was then gently extended and ulnar deviated to reduce the flexed scaphoid and close the scapholunate (SL) gap. The definitive fixation was performed in a manner described below. We found the lunotriquetral (LT) joint to reduce anatomically once the lunate had been reduced. Thus it was not specifically repaired or wired, as it was not deemed that additional stabilisation was required. We feel that the majority of clinicians managing these injuries acknowledge that SLIL and the development of scapholunate advanced collapse (SLAC) is the major concern rather than problems with the ulna side of the wrist.
If closed wrist reduction was not possible, open reduction was performed through a dorsal approach described by Berger 14 between the 3 rd and 4 th extensor compartments. Extensor pollicis longus (EPL) was released and a radially based capsular flap created, preserving the radiotriquetral ligament. All cartilaginous debris was removed and any cartilaginous damage to the scaphoid and capitate noted. An anatomic reduction was achieved of both the scapholunate and lunotriquetral articulations and the reduction was held in the same manner as described below. No attempt was made to repair the SLIL or the LT ligament.
It was imperative that an anatomical reduction of the SL and LT articulation was achieved and confirmed with intra-operative screening. A scapholunate (SL) gap less than 2mm, a scapholunate (SL) angle between 30° and 60° and a radiolunate angle of less than 10° was accepted as reduced.
The radial sensory nerve was protected by blunt dissection down to styloid. Two smooth percutaneous 1.6mm K-wires were placed just distal to the radial styloid, one from the scaphoid into the lunate to maintain the scapholunate reduction and one from the scaphoid into the capitate to prevent scaphoid flexion. The wires were cut short and buried beneath the skin. No wires were inserted from the triquetrum to the lunate.
All patients were placed in a below elbow thumb SPICA plaster in approximately The presence of osteoarthritic changes of the radiocarpal and mid-carpal joints were also recorded. The senior author, using the same radiographic landmarks, performed all measurements. SL distance was measured as the distance between the scaphoid cortex and the lunate cortex at the centre of the scapholunate joint. 15 The SL angle was measured between the longitudinal axis of the lunate (drawn perpendicular to a line joining the dorsal and volar poles of the lunate) and a line intersecting the volar cortices of the proximal and distance convexities. 16

Statistical methods
Subject characteristics were summarized using descriptive statistics; for continuous variables, means and standard deviations are reported, and for categorical variables, counts and percentages are reported. Despite the small number of study subjects, the normality of the distribution of continuous data was assessed using the Shapiro Wilk Test. Normally distributed data was summarised using means and standard deviations and the means compared in the two groups using the Student's t-test. Skewed data was summarised using the median and range and the medians were compared using the Wilcoxon Rank-Sum/Mann Whitney U-test. Proportions in the two groups were compared using Fisher's exact test. The level of statistical significance was set at p<0.05.

g. Results
The  Max 30). 9 of the 10 patients reported no pain with 1 patient reporting only mild, occasional pain. This was reflected in the Mayo score that showed an excellent score in 3 patients (30%), good in 2 (20%) and fair in 5 (50%). Sixty percent of patients returned to work, while 20% were unemployed at time of follow-up but found work subsequently. Only 20% did not return to work and this was due to other injuries sustained.
One of the 10 patients had a positive Watson Scaphoid Shift test but was asymptomatic. No patients had a positive finger extension test. The wrist range of movement and grip strength of the total group, for the injured side, was 76% and 90% respectively compared to the normal side.
The good clinical instability scores were in contrast to the radiological variables with none being in the range that the study deemed acceptable at final follow-up.
Again the small numbers prevented significant statistical correlation, however the poor radiological scores did not correlate with poor clinical scores. 2 of the 9 patients showed arthritic changes on x-ray at final follow-up but experienced no pain clinically.
There were no post-operative complications such as sepsis, broken metalware or arthrofibrosis.

Discussion
There is currently no disagreement in the literature concerning the importance of the scapholunate relationship in wrist biomechanics and whether accurate reduction of the carpus is imperative to favourable long-term outcome in PLD's. 11,[17][18][19][20] However there is controversy as to whether to achieve reduction via open or closed means and how to maintain the scapholunate relationship. There is no clear evidence to suggest that open reduction and acute repair of the SLIL is advantageous to closed reduction and pinning alone. Currently there is only one small study by Inoue and Kuwahata 21 , of 14 patients, that compares closed reduction and pinning to open reduction, SLIL repair and pinning. In this study no statistical difference in outcome between these two groups was found. 21 Open treatment, including ligament repair, is aimed at preventing scapholunate advanced collapse, i.e. the SLAC wrist. The SLAC wrist is seen with acceleration of the post-traumatic osteoarthritis and wrist instability found with conservative treatment at long-term follow-up. However when looking at whether or not an open reduction and internal fixation, without repair of the SLIL, is beneficial to a good radiological score and functional outcome, a study by Forli et al 11 , who has the longest follow up with an average of 13 years (range, 10-25). He concludes that there is a tendency for patients to show degenerative changes on x-ray with time and that good reduction, not necessarily the SLIL repair, results in a better radiological score. He also states that poor reduction results in worse degenerative changes however that this does not seem to translate into a poor functional outcome. 11 In our study we achieved anatomic reduction in 7 of 10 patients with closed manipulation, which is comparable to that of Adkison et al. 3 Of these only 1 patient showed signs of osteoarthritis on x-ray follow-up and  Although not as comprehensive as some of the more recent PROMs such as the patient related wrist evaluation score, we did use the Mayo wrist score to assess functional outcomes. We chose this scoring system, as did many of the landmark articles on this topic, in order to achieve meaningful comparison with them.
Potential bias exists in the study's interpretation of the postoperative x-rays. Only the senior surgeon in the study performed the analysis with no independent control. However, this was a radiological assessment, based on objective criteria and it should be noted that the radiological parameters were not within normal range and reported as such, which speaks to their objectivity.

i. Conclusion
In conclusion the results of this study shows that the closed reduction and pinning

Title of submission
Clinical outcomes following reduction and pinning of lesser arc injuries without repair of the scapholunate interosseous ligament.
This letter is to certify that: • All the authors have been actively involved in the planning and enactment of the study, and have also assisted with the preparation of the submitted article.    • Selects out group that will benefit from more extensive reconstructive surgery. This study is being done to assess the long term clinical and functional outcomes of perilunate /lunate dislocations treated conservatively at Groote Schuur hospital. The clinical outcomes measured would be the final range of movement of the wrist and grip strength. The functional assessment involves assessing your pain and ability to return to work or sporting activity. There are multiple ways of treating these injuries and we are comparing our results with other described methods.

l. Tables & figures
Why are you being asked to take part?
These are rare injuries and more information is needed to better manage these problems.
How many people will take part in the study?
We estimate that roughly 15 people will be involved What will happen if you decide to take part in the study?
All patients will have an x-ray which will be at no extra cost to you. Your wrist movement and function will be examined and scored. You will be asked to fill in a brief questionnaire.
This process will take approximately 45 min. You may be required to return for a further visit in future to undergo the same investigations, but you will be informed at the time of your initial follow up.

What are the risks and discomforts of this study?
There is no risk associated in participating in this study.
Are there any benefits to you for being in the study?
Being part of this study will not influence your management in any way and therefore there is no benefit to you directly. The benefit however will be for us as doctors as information gained through this study may help us in understanding of the management of this injury. You will not be paid to take part in this study.

What other choices do you have?
It is completely your choice to take part in the study.

What will happen when the study is over?
Once you have had your x-ray, completed the questionnaire and had the physical examination you will be finished with the study.

Will the results of the research be shared with you?
The overall results will be shared with you at the end of the study if you are interested.
None of the personal details of any of the other people who were part of the study will be revealed.

Will you receive any reward (money or food vouchers) for taking part in this study?
You will not be paid for taking part in this study.

Who will see the information which is collected about you during the study?
All the information collected for this study will be kept anonymous and confidential. All information will be kept on computers which will be protected by a password. Only the research team will have access to this information. Part of the study is that these results will be presented at congresses and in journals. No personal details of the patients from the study will be included in these presentations.

Who do I speak to (or contact) if I have any questions about the study?
You can speak to the study coordinator Dr David Chivers Authors are required to submit their manuscripts after reading the following instructions. Any manuscript that does not conform to the following requirements will be considered inappropriate and may be returned.

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I. References.
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