Concomitant injuries affect prognosis in patients with central slip tear

Accepted Manuscript

Concomitant Injuries Affect Prognosis in Patients with Central Slip Tear Yuki Fujihara , Hideyuki Ota , Kentaro Watanabe PII: DOI: Reference:

S1748-6815(18)30185-2 10.1016/j.bjps.2018.05.031 PRAS 5691

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Journal of Plastic, Reconstructive & Aesthetic Surgery

Received date: Revised date: Accepted date:

29 December 2017 9 April 2018 27 May 2018

Please cite this article as: Yuki Fujihara , Hideyuki Ota , Kentaro Watanabe , Concomitant Injuries Affect Prognosis in Patients with Central Slip Tear, Journal of Plastic, Reconstructive & Aesthetic Surgery (2018), doi: 10.1016/j.bjps.2018.05.031

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Concomitant Injuries Affect Prognosis in Patients with Central Slip Tear Yuki Fujihara (YF) Hideyuki Ota (HO) Kentaro Watanabe (KW)

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Department of Orthopaedic Surgery, Nagoya Ekisaikai Hospital, 4-66 Shonen-Cho, Nakagawa-Ku, Nagoya 454-8502, Japan

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Corresponding author: Yuki Fujihara, M.D., Ph.D. Department of orthopaedic surgery Nagoya Ekisaikai Hospital

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4-66 Shonen-Cho, Nakagawa-Ku, Nagoya 454-8502, Japan

Fax: (+81) 052-652-7783

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Tel: (+81) 90-9944-4925

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E-mail: [email protected]

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Summary Central slip tears often occur with concomitant hand injuries. However, the outcome of a central slip tear and the effect of concomitant injuries are rarely reported. We evaluated 67 fingers in 63 patients with central slip tears who underwent primary surgery in our hospital between April 2009 and June 2017. We performed multivariate analyses; on proximal

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interphalangeal joint active range of motion and existing extension lag greater than 10 degrees as dependent variables, and age, existence of concomitant fractures, skin defects, collateral ligament injuries, ruptured lateral bands, ruptured flexor tendons, or vascular injury in the injured finger as independent variables. Concomitant injuries of tendons in the adjacent fingers were also independent variables. The average active range of motion of the proximal

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interphalangeal joint was 62 degrees, and extension lag occurred in 34 fingers (51%). Patients aged >40 years with fractures of the injured finger or flexor tendon injuries in an adjacent finger had lower decreases in active range of motion (partial regression coefficient [95% CI]: -13.7 [43–66], -31.6 [30–57], -34.5 [32–60], and -33.5 [10–43], respectively). Extensor

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tendon injuries in an adjacent finger caused significantly more extension lag in the proximal interphalangeal joint (odds ratio [95% CI]: 3.2 [1.0–9.6]). The present study indicated the

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negative impact of a tendon injury on adjacent fingers, a circumstance widely known as the quadriga phenomenon. Ultimately, we can use these prognostic factors in surgical repair

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planning, particularly when comparing treatments such as central slip reconstruction and

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primary arthrodesis.

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Key words: central slip tear, extensor tendon injury, quadriga phenomenon

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Introduction Central slip tear often occurs with several concomitant injuries, such as fracture, flexor tendon injury, lateral band injury, or dorsal skin defect of proximal interphalangeal (PIP) joint; these complex injuries are often difficult to treat.1-3 Walsh et al. presented a preferable outcome after central slip repair, but they excluded patients with concomitant injuries.

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However, they mentioned that central slip tear often accompanies concomitant injuries in their report.3 O'Dwyer et al. reviewed patients with concomitant injuries, and indicated that no patient had an excellent outcome in their study.1 Regarding treatment for these complex injuries, we need to perform the appropriate reconstruction of the tissues and prioritize repair, if necessary. For example, it is unnecessary to repair a unilateral injury of the lateral band,

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because the injury does not cause any functional deficits.4 Arthrodesis of the fractured PIP joint may need to be performed, including central slip repair in the amputated finger replantation, despite joint reconstruction if the prognosis of joint function is poor, because finger shortening enables the easier construction of anastomoses. These decisions are,

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however, based mainly on the expert opinion and experimental rules, because few studies have evaluated these prognostic factors.

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Moreover, tendon injuries in the adjacent fingers, which frequently appear, can also affect the outcome of central slip repair. The quadriga phenomenon, which was originally

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reported as dysfunction occurring in the non-damaged finger adjacent to the finger with flexor

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tendon injury, can also worsen outcomes.5,6 Furthermore, a similar phenomenon can occur among extensor tendons adjacent to each other, which are connected by juncturae tendinum.7,8

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To date, however, few studies have reported clinical data on these phenomena. Thus, the aim of this study was to identify the prognostic factors of functional outcome after central slip tear.

Materials and Methods This retrospective observational study was approved by our institutional review board. We conducted this study at a single general hospital. We performed a retrospective review of 3

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our institution’s electronic medical records from April 2009 to June 2017 to identify patients with >50% central slip tear in the fingers, as this degree of injury requires surgical intervention.4 Exclusion criteria were as follows: age <18 years, primary arthrodesis or stump closure of the PIP joint, and a follow-up period <8 weeks. We performed simple tendon repair whenever possible, and used suture anchors only when the distal stump of the central slip was

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too short to suture. After static splinting in a protective position for 3 weeks, intense physical therapy was carried out until a plateau in improvement occurred.

We included 67 fingers in 63 patients (57 men and 6 women) in this study. Patient inclusion details are shown in Figure 1. The mean follow-up period was 10±9 months (mean ±SD), and the outcome of the treatment was examined at the final follow-up. We defined PIP

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joint active range of motion (AROM) as a primary outcome, and the existence of extension lag >10 degrees as a secondary outcome. We extracted data such as age, existence of concomitant fracture, skin defect, collateral ligament injury, lateral band rupture, flexor tendon rupture, and vascular injury in the injured finger and included them as possible

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prognostic factors. Concomitant flexor and extensor tendon injuries in adjacent fingers were

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Statistical analysis

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also included.

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We analysed age as a categorical variable using two categories (>40 years and ≤40 years). PIP-joint AROM was proved to be a normally distributed variable by Shapiro-Wilk

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normality test. Because PIP-joint AROM is a continuous variable, we used a linear regression model to identify prognostic factors for the loss of PIP-joint AROM. We built a logistic regression model and considered variables that were significant at an a = 0.1 in bivariate analysis for both models to identify risk factors for the incidence of extension lag. Both multivariate models were built using backward stepwise regression, stopping when all remaining covariates were significant at an a = 0.05 significance level. We reported the partial regression coefficient for the primary outcome, odds ratios (ORs) for the secondary outcome, 95% confidence intervals (95% CIs) for both, and P values for both of multivariate results. All 4

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statistical analyses were performed with EZR (Saitama Medical Center, Jichi Medical University, Saitama, Japan), which is a graphical user interface for R (The R Foundation for Statistical Computing, Vienna, Austria),9 which is a modified version of R commander designed to add statistical functions frequently used in biostatistics.

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Results The average AROM of the PIP joint was 62 degrees and extension lag occurred in 34 fingers (51%) (Tables 1 and 2). On linear regression analysis, PIP-joint AROM in patients with age >40 years, phalangeal or intraarticular fracture in the injured finger, or flexor tendon injury in the adjacent finger was lower (Table 3A, B). On univariate and multivariate logistic

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regression analysis, extensor tendon injury in the adjacent finger had a significant correlation with more extension lag in the PIP joint (OR: 3.2; 95% CI: 1.0-9.6) (Table 4). The number of fingers in the targeted group was >30, which fulfilled the minimum number to evaluate three or less factors in regression analysis.10,11 Eighteen fingers underwent extensor or flexor

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tenolyses, 2 fingers required secondary surgical arthrodesis of the PIP joint, and 4 fingers lost function of the PIP joint completely without additional surgical intervention. Four of the 6

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fingers that lost PIP joint function had concomitant fracture and 3 fingers had multiple

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injuries.

Discussion

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In the current study, we identified a strong influence of tendon injuries in the adjacent fingers on an index of postoperative PIP-joint function (AROM and extension lag) after central slip repair. PIP joints with flexor tendon injury in the adjacent finger showed worse postoperative AROM. Postoperative extension lag was found in higher frequency with extensor tendon injury in the adjacent finger. As expected, age >40 years and fractures in the injured finger also decreased the postoperative AROM of the PIP joint. Though several authors have reported the outcome of extensor tendon repair, studies show a high variability in the zones researched.12-16 Carl et al. examined 205 fingers with 5

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primary extensor tendon repair and analysed the relationship between the zone of injury or other prognostic factors and its postoperative outcome; they concluded that the complexity of trauma and anatomical zone of tendon injury strongly affects the outcome. Considering its complex structure, different zones of extensor tendon injury should be evaluated accordingly. A few authors have reported the results of early active motion after extensor tendon repair;

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however, the efficacy of these protocols can be different depending on the injured zone.13,17 Hammond et al. conducted a systematic review on postoperative rehabilitation after extensor tendon repair in 2012.18 However, they could not perform statistical analyses because of the variability in the reviewed literature. We focused on a specific structure of the extensor tendon, the central slip, which reduced the variability on of our results.

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Regarding central slip tear, only a few studies have been reported, and most showed the superiority of an early active mobilisation protocol to conventional immobilization for >3 weeks.1,3,19,20 Several authors mentioned the negative effect of concomitant injuries in central slip tears.1-3 Although most central slip tears occur with concomitant injuries owing to the

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structure of the dorsal aspect of the PIP joint, studies have not appropriately assessed the

in our clinical practice.

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effect of concomitant injuries. From this perspective, the results of our study were beneficial

In this study, we chose to adopt a different treatment strategy for patients with negative

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prognostic factors, such as fracture, age >40, or tendon injury in the adjacent fingers. We

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chose a more aggressive therapy regime compared to the conventional one for these patients to improve their functional result. In addition, it could be rationalized to choose primary PIP

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joint arthrodesis for patients with these factors to avoid delay of postoperative rehabilitation initiation, which could lead to better finger functionality. In fact, 6 fingers in our series lost PIP joint function, and most showed poor functional outcome. They might achieve a better result with a different treatment strategy. In addition, our study clarified the negative effect of tendon injury on function of the adjacent finger, which is widely known as the quadriga phenomenon.5,21 Although there is currently awareness of this phenomenon by most hand surgeons, few studies have presented actual data on it. Silfverskiold et al. reported the negative effect of multiple digit injuries on 6

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outcomes after zone II flexor tendon repair in their prospective studies.22,23 Although they did not mention the quadriga phenomenon, it could be a rationale for the occurrence of this negative effect. The extensor quadriga phenomenon is much less popular than that of the flexor tendon phenomenon, and very few authors have reported on its clinical outcome.8,24 In that respect, our study is valuable.

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Our study has several limitations. First, because of its retrospective nature, we cannot conclude causation. Further prospective study is necessary to clarify our findings. Second, our study had a small sample size. Although we performed backward stepwise regression to reduce the number of variables, this could reduce the quality of our study. Third, we did not adopt early mobilisation after surgery, which may produce better results than immobilization.

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In conclusion, we presented the clinical result of central slip repair and examined factors for poor prognosis, very few of which are reported. Although we cannot recommend primary arthrodesis based only on our study results this finding can aid surgeons in choosing a surgical procedure to treat central slip tears. In addition, we can further validate the existence

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of the flexor and extensor quadriga phenomena with clinical data.

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Conflict of interest statement: None.

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References 1. O'Dwyer FG, Quinton DN. Early mobilisation of acute middle slip injuries. J Hand Surg Br 1990;15;404-6.

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2. Hung LK, Chan A, Chang J, Tsang A, Leung PC. Early controlled active mobilization with dynamic splintage for treatment of extensor tendon injuries. J Hand Surg Am 1990;15;251-7.

3. Walsh MT, Rinehimer W, Muntzer E, Patel J, Sitler MR. Early controlled motion with dynamic splinting versus static splinting for zones III and IV extensor tendon lacerations:

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a preliminary report. J Hand Ther 1994;7;232-6.

4. Strauch RJ. Extensor Tendon Injury. In Green, David P. Wolfe, Scott W. (ed): Operative Hand Surgery, 6th ed, New York, Churchill Livingstone, 2011: 160-88. 5. Verdan C. Syndrome of the quadriga. Surg Clin North Am 1960;40;425-6.

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6. Giambini H, Ikeda J, Amadio PC, An KN, Zhao C. The quadriga effect revisited: designing a "safety incision" to prevent tendon repair rupture and gap formation in a

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canine model in vitro. J Orthop Res 2010;28;1482-9. 7. Wilhelm A. [The quadriga phenomenon of the extensor tendon system and the superficial

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transverse metacarpal ligament]. Handchir Mikrochir Plast Chir 1988;20;173-9.

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8. Chinchalkar SJ, Gan BS, McFarlane RM, King GJ, Roth JH. Extensor quadriga: Pathomechanics and treatment. Can J Plast Surg 2004;12;174-8.

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9. Kanda Y. Investigation of the freely available easy-to-use software 'EZR' for medical statistics. Bone Marrow Transplant 2013;48;452-8.

10. Peduzzi P, Concato J, Feinstein AR, Holford TR. Importance of events per independent variable in proportional hazards regression analysis. II. Accuracy and precision of regression estimates. J Clin Epidemiol 1995;48;1503-10. 11. Peduzzi P, Concato J, Kemper E, Holford TR, Feinstein AR. A simulation study of the number of events per variable in logistic regression analysis. J Clin Epidemiol 1996;49;1373-9. 8

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12. Mehdinasab SA, Pipelzadeh MR, Sarrafan N. Results of primary extensor tendon repair of the hand with respect to the zone of injury. Arch Trauma Res 2012;1131-4. 13. Crosby CA, Wehbe MA. Early protected motion after extensor tendon repair. J Hand Surg Am 1999;24;1061-70. 14. Karabeg R, Arslanagic S, Jakirlic M, Dujso V, Obradovic G. Results of primary reparing

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of hand extensor tendons injuries using surgical treatment. Med Arch 2013: 67: 192-4. 15. Newport ML, Blair WF, Steyers CM, Jr. Long-term results of extensor tendon repair. J Hand Surg Am 1990;15;961-6.

16. Carl HD, Forst R, Schaller P. Results of primary extensor tendon repair in relation to the zone of injury and pre-operative outcome estimation. Arch Orthop Trauma Surg

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2007;127;115-9.

17. Howell JW, Merritt WH, Robinson SJ. Immediate controlled active motion following zone 4-7 extensor tendon repair. J Hand Ther 2005;18;182-90.

18. Hammond K, Starr H, Katz D, Seiler J. Effect of aftercare regimen with extensor tendon

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repair: a systematic review of the literature. J Surg Orthop Adv 2012;21;246-52. 19. Maddy LS, Meyerdierks EM. Dynamic extension assist splinting of acute central slip

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lacerations. J Hand Ther 1997;10;206-12. 20. Evans RB. Early active short arc motion for the repaired central slip. J Hand Surg Am

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1994;19;991-7.

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21. Schreuders TA. The quadriga phenomenon: a review and clinical relevance. J Hand Surg Eur Vol 2012;37;513-22.

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22. May EJ, Silfverskiöld KL, Sollerman CJ. Controlled mobilization after flexor tendon repair in zone II: a prospective comparison of three methods. J Hand Surg Am 1992;17;942-52.

23. Silfverskiöld KL, May EJ, Oden A. Factors affecting results after flexor tendon repair in zone II: a multivariate prospective analysis. J Hand Surg Am 1993;18;654-62. 24. Chinchalkar SJ, Barker CA, Owsley B. Relationship between juncturae tendinum and sagittal bands. J Hand Microsurg 2015;7;96-101. 9

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Figure legend

Figure 1: Patient flow diagram Diagram of the inclusion and exclusion of patients

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Table 1. Prognostic factors and PIP-joint AROM

Injured finger

Treatment

Central slip tear

≤40 years

34

>40 years

33

Anchor

19

Suture

41

Others

7

Partial Complete

AROM

(°)

(°)

68

69

59－80

68

55

43－67

60

56

41－71

75

68

59－78

35

43

14－72

95% CI

15

90

78

61－95

52

60

58

49－66

59

70

66

58－74

8

18

24

8－41

None

injury

Injured

Lateral band

Intact

28

90

76

63－89

injury

Unilateral

22

60

56

44－69

Bilateral

17

50

47

34－60

Intact

56

70

66

58－75

Unilateral

4

25

33

3－62

Bilateral

7

40

43

20－67

None

33

90

81

71－90

Diaphysis

19

40

43

32－55

PIP intraarticular

15

50

46

28－63

Collateral

None

56

70

64

55－72

ligament injury

Unilateral

8

65

64

42－86

Bilateral

3

50

34

-40－108

None

55

70

67

59－75

Skin defect

12

35

39

18－59

None

57

70

68

61－76 11

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Flexor tendon

Arterial injury

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Fracture

Skin defect

Adjacent

AROM

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Age

n

Mean

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Factors

Median

Flexor tendon

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finger

injury

Injured

10

28

27

14－39

Extensor tendon

None

47

70

67

57－76

injury

Injured

20

50

52

37－67

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AROM: active range of motion, PIP: proximal interphalangeal

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Table 2. Prognostic factors and PIP=joint extension lag

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+

Lag (%)

Injured finger

Treatment

15

19

44.1

>40 years

19

14

57.6

Anchor

8

11

42.1

Suture

21

20

51.2

Others

5

2

71.4

Partial

8

7

53.3

24

23

46.2

28

21

47.5

6

2

75.0

11

17

39.3

13

9

59.1

Bilateral

10

7

58.8

Intact

24

31

42.9

Unilateral

3

1

75.0

Bilateral

7

0

100.0

None

14

19

42.4

Diaphysis

14

5

73.7

6

9

40.0

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Central slip tear

≤40 years

Complete

intraarticular None

30

26

53.6

injury

Unilateral

3

5

37.5

Bilateral

1

2

33.3

None

28

27

50.9

Skin defect

6

6

50.0

None

24

33

42.1

Flexor tendon injury

None Injured

Lateral band injury

Intact

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Unilateral

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Fracture

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Arterial injury

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Collateral ligament

Adjacent

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Age

Skin defect

Flexor tendon injury

PIP

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finger

Injured

10

0

100.0

Extensor tendon

None

20

27

42.6

injury

Injured

14

6

70.0

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PIP: proximal interphalangeal

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Table 3A. Univariate linear regression analysis of PIP-joint AROM Partial regression Factors

95% CI

p value

coefficient

Treatment

-

-

-

>40 years

-8.1

43－67

0.18

-

-

-

Suture

6.9

53－84

0.39

Others

7.5

19－66

0.54

Partial

-

-

-

-8.4

43－72

0.27

-

-

-

15.3

10－39

0.27

-

-

-

Anchor

Central slip tear

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Injured finger

≤40 years

Complete None

injury

Injured

Lateral band

Intact

injury

Unilateral

-7.4

41－72

0.35

Bilateral

-3.4

29－64

0.71

-

-

-

Unilateral

-5.7

4－61

0.70

Bilateral

14.7

18－69

0.26

-

-

-

Diaphysis

-31.2

27－60

0.00

PIP intraarticular

-28.6

28－63

0.00

-

-

-

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Flexor tendon

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Arterial injury

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Fracture

Intact

None

Collateral

None

ligament injury

Unilateral

11.4

43－84

0.28

Bilateral

-30.8

0－69

0.09

-

-

-

-13.6

21－57

0.15

-

-

-

Skin defect

None Skin defect

Adjacent

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Age

Flexor tendon

None

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finger

injury

Injured

Extensor tendon

None

injury

Injured

-53.1

4－49

0.00

-

-

-

9.5

37－67

0.22

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AROM: active range of motion, PIP: proximal interphalangeal

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AROM: active range of motion, PIP: proximal interphalangeal

Table 3B. Multivariate linear regression analysis of PIP joint AROM Partial regression Factors

95% CI

p value

-

-

coefficient ≤40 years

-

>40 years

-13.7

Fracture in the

None

injured finger

Diaphysis

-31.6

PIP intraarticular

-34.5

None

-

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Flexor tendon injury

-

-33.5

0.020

-

-

30－57

0.00

32－60

0.00

-

10－43

-

0.00

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in the adjacent finger Injured

43－66

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Age

17

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Table 4. Univariate Logistic regression analysis of PIP joint extension lag

Age

Injured finger

Treatment

Odds ratio

95% CI

p value

≤40 years

-

-

-

>40 years

4.3

1.1－17.0

0.036

-

-

-

0.6

0.1－3.1

0.499

2.8

0.1－65.7

0.532

-

-

-

0.4

0.1－2.1

0.282

-

-

-

0.0

0.0－Inf

0.996

-

-

-

injury

5.2

0.9－31.2

0.071

Bilateral injury

1.3

0.1－15.8

0.849

-

-

-

Anchor Suture Others

Central slip

Partial

Flexor tendon

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Complete Intact

Injured Lateral band

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Factors

Intact

Artery

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Unilateral

Intact

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Unilateral

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Bone

injury Bilateral injury Intact

0.0－ 3.4

241.0

0.569

1.E+24

0.0－Inf

0.994

-

-

-

1.7

0.2－12.8

0.608

0.3

0.0－4.9

0.428

-

-

-

0.3

0.0－3.4

0.337

Diaphyseal fracture PIP intra-articular fracture

Collateral ligament

Intact Unilateral

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injury Bilateral injury Skin

0.0

0.0－Inf

0.997

-

-

-

0.2

0.0－4.9

0.336

-

-

-

2.E+15

0.0－Inf

0.994

No defect Skin defect

Flexor tendon

finger

Intact Injured

Extensor tendon

Intact Injured

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Adjacent

-

-

-

1.4

0.2－8.9

0.742

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AROM: active range of motion, PIP: proximal interphalangeal

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