COMPRESSION HUMERUS INTERLOCK NAILING : A STUDY TO UNDERSTAND &

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1 COMPRESSION HUMERUS INTERLOCK NAILING : A STUDY TO UNDERSTAND & OVERCOME THE DRAWBACKS OF INTERLOCK NAIL SYSTEM DISSERTATION SUBMITTED TO UNIVERSITY OF SEYCHELLES AMERICAN INSTITUTE OF MEDICINE IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE M.Ch. [ORTHOPAEDIC SURGERY] BY DR. BHASKAR PRANI JULY

2 ABSTRACT : BACKGROUND: Unlike Femur & Tibia, outcome of interlock nailing of humeral shaft fractures is controversial. Distraction force, lack of absolute rotational stability, compressibility & shoulder pain/stiffness are probable drawbacks of current interlock system.variations in implants, operative technique and follow-up parameters hinder comparative studies. The aim of this investigation was to evaluate the Compression Humerus Interlock Nailing System according to clinical results, and to recognise advantages and disadvantages of compression interlocking. METHODS: 14 Humeral shaft fractures were treated with Compression Humerus Interlock Nail System. In all cases the antegrade approach was used. Compression locking was performed in all cases using 4Nm Torque Screw Driver. This study was compared to a group of 15 cases treated by Static Humerus Interlock Nail System. RESULTS: Radiological evidence of calus formation in C H I L Nail group was evident in all 10 cases in closed nailing group by 12 weeks & in 4 non-union cases group treated by additional bone grafting by 18 weeks. While 16 and 22 weeks in static interlock group respectively. Comparatively there were no significant complications including I.L. Bolt bending or loosening. Shoulder stiffness was minimized by early mobilization & physiotherapy. CONCLUSION: Antegrade Compression Humerus Interlock System can result in good functional outcome and unimpaired quality of life. Compression interlocking can minimise the fracture gap and increase the biomechanical stiffness as well. Potential disadvantages of compression interlocking include possible bending or loosening of the locking screw in the dynamic oblong hole. This is avoidable by using graduated torque screw driver while achieving compression. 2

3 INTRODUCTION Amongst the operative options for diaphyseal fractures of humerus, compression plating & interlock nailing are popular methods. Interlock nailing has advantages of closed implantation ease and secure fixation. However it has drawbacks viz. lack of compression at fracture site, lack of absolute rotational and distraction stability & shoulder stiffness. Unlike femur & tibia there is lack of dynamic compression force. On the contrary weight of upper limb when not supported tends to distract the fracture. Compression humerus interlock nail system can overcome most of the disadvantages of static interlock system. The concentric axial compression minimizes the fracture gap, holds the fracture fragments in strong opposition & prevents rotational and distraction instability. There are very few references about compression humerus interlock nail till today. The T2 Nail [Stryker] has a possibility of bending or loosening of the bolt in dynamic hole & it has been recommended to use additional static locking in the system. AIMS AND OBJECTIVES To compare advantages & disadvantages To study the incidence of complications with this method of static & compression interlocking To study drawbacks of static locking in in-vitro models and cadaveric bones To achieve safety and to minimize probable complications of compression interlocking 3

$MATERIAL AND METHOD 14 cases of diaphyseal fracture Humerus were stabilized with Compression Humerus Interlock Nail [C H I$ The C H I L Nails were available in the diameter of 7 & 8 mm and the length 22, 24, 26 & 28 cm.

The C H I L Nails were available in the diameter of 7 & 8 mm and the length 22, 24, 26 & 28 cm.

9 mm interlock bolts with length of 20, 22 & 24 mm were available. The distal interlocking was antero-posterior oriented.

4 MATERIAL AND METHOD 14 cases of diaphyseal fracture Humerus were stabilized with Compression Humerus Interlock Nail [C H I L NAIL] by antegrade approach. The C H I L Nails were available in the diameter of 7 & 8 mm and the length 22, 24, 26 & 28 cm. Distally one or two hole options with hole diameter of 4 mm with 3.9 mm interlock bolts with length of 20, 22 & 24 mm were available. The distal interlocking was antero-posterior oriented. Proximally the nail diameter was 10 mm to accommodate 5 mm capsule hole & a 4.9 mm interlock bolt with length options of 25, 30, 35 & 40 mm in medio-lateral orientation. The nail by design had a proximal bend of 5 degree to accommodate the offset of the insertion portal with the medullary canal. 4

$At proximal end the nail has been provided with a top screw with length 35 mm to achieve compression at the fracture site Preoperative estimation of medullary canal diameters was done on computerized$

5 At proximal end the nail has been provided with a top screw with length 35 mm to achieve compression at the fracture site Preoperative estimation of medullary canal diameters was done on computerized radiographs & only large diameter cases were selected for I M Nailing. D C P or L C P fixation was preferred for smaller diameters. Anaesthesia : All cases were operated under Interscalene Brachial Block augmented in some cases with Subcoracoid Block. Approach : All cases were operated through antegrade approach. Procedure : Supine position on eccentric loaded radiolucent table with patient s head towards foot end & a bump under scapula. Image Intensifier on the opposite side. Scrubbing painting & draping according to standard protocol. A 1.5 cm incision just lateral to acromion along the direction of rotator cuff fibres.the entry portal made just medial to tip of greater tuberosity & about 5 5

6 mm behind bicipital groove with a small awl. The position confirmed on image intensifier. 6

A 2.4 mm beaded guidewire inserted and advanced down the canal after achieving reduction under image intensifier. Reaming with flexible reamers with serial increments of 0.

7 A 2.4 mm beaded guidewire inserted and advanced down the canal after achieving reduction under image intensifier. Reaming with flexible reamers with serial increments of 0.5 mm, inough to accommodate nail of 0.5 mm smaller diameter. Measurement of length of canal before changing the guidewire with a nonbeaded one. Cannulated nail insertion over the guidewire, holding the fracture ends in allignment & correct rotation. Care taken to keep tip of nail atleast 5 mm beneath the bone with fracture in non distracted position. 7

8 8

9 9

$Distal interlock done first with 3.9 mm I L Bolt under image intensifier. 2 bolts were preferred when the fracture was in distal third.$

10 Distal interlock done first with 3.9 mm I L Bolt under image intensifier. 2 bolts were preferred when the fracture was in distal third. The fracture was impacted using extractor assembly & light blows. Proximal interlock performed through the jig with 4.9 mm bolt of appropriate length. 10

$After removing top bolt of the jig but before removing the jig, the top screw was passed & tightened with 4 Nm Torque Screwdriver to achieve compression at fracture site.$

11 After removing top bolt of the jig but before removing the jig, the top screw was passed & tightened with 4 Nm Torque Screwdriver to achieve compression at fracture site. The incisions were closed with a single stitch at each place. Sterile dressings applied & the limb was kept in pouch arm sling. Postoperative management : Rehabilitation of patient began immediately. The operated limb was elevated on a Thomas arm splint or by suspension. From 2 nd postop day active assisted and passive movements were begun including pendulum exercises and assisted full forward flexion within limits of pain. From 7 th postop day overhead abduction & rotation exercises were begun. Follow up Protocol : The patient was called for follow up at intervals of 3 to 6 weeks as per need in indivisual case. Depending on clinical & radiological picture further follow ups were advised. Advice regarding lifting of weight and heavy work was given depending on X-ray picture & not before 4&1/2 months. The Constant Murley shoulder score and the A S E S score was chosen for assessment of functional recovery of upper limb. 11

12 STATISTICS : The present study includes 29 patients having diaphyseal humerus fractures in the mid & distal third. 14 cases were treated with Compression Humerus Interlock Nailing. 15 cases were treated with Static Interlock Nailing. In both groups 4 cases in each, additional bone grafting was done. In Compression Interlock group 10 were fresh fractures & 4 nonunions, while in the Static Interlock group 11 fresh fractures & 4 nonunions. Analysis of the data is presented here : Table 1 : Age distribution Age Group [Years] No of Patients [CHIL Nail] No of Patients [Static & % Nail] & % & above Nil Nil Total Sex Table 2 : Sex distribution No of Patients [CHIL Nail] % No of Patients [Static Nail] % Total Male [66%] Female [34%] Table 3 : Site Interlock system Middle Third Mid Third / Lower Third CHIL Nail 9 [ 64%] 5 [ 36%] Static Nail 9 [ 60%] 6 [ 40%] Total 18 [ 62%] 11 [ 38%] 12

13 Table 4 : Radial nerve injury Radial nerve palsy On admission After surgery CHIL Nail 1 [ 07.1%] 1 [ 07%] Static Nail 2 [ 13.3%] 1 [ 07%] Total 3 [ 10.3%] 2 [ 07%] Table 5 : Nail Diameter used Nail Diameter 8 mm 7 mm CHIL Nail 9 [ 64%] 5 [ 36%] Static Nail 9 [ 60%] 6 [ 40%] Table 6 : Time taken for Union Time [Weeks] Less than CHIL Nail 8 [ 57%] 4 [ 29%] 2 [ 14%] More than 30 Static Nail 4 [ 27%] 7 [ 46%] 2 [ 13%] 1 [7%] 1 [ 7%] Total One case in static interlock group had broken proximal interlock & non union, was treated with additional stabilization and bone grafting as second procedure. Table 7 : Assessment of Shoulder Function at the end of 6 Months Constant Score No. of pts [CHIL Nail] No. of pts [STATIC Nail] 55 & above 10 [ 71%] 07 [47%] [ 29%] 05 [ 33%] [ 13%] [ 07%] < 40 Total Using Constant-Murley scoring system, 71% patients in CHIL Nail group had a score above 55% implying excellent shoulder function. Comparatively 47% patients in Static Nail group had excellent shoulder function. No patient in either group had a score less than 40 implying poor shoulder function. 13

14 TABLE 8 : A.S.E.S. Upper limb function score A.S.E.S. Score No. of pts [CHIL Nail] No. of pts [STATIC Nail] Total Table 9 : Complications Complications encountered CHIL Nail group Static Nail group Shoulder stiffness Nil 01 Elbow stiffness Nil Nil Implant Failure Nil 01 Infection Nil Nil Delayed Union Nil 02 Nonunion Nil 01 Iatrogenic Radial Palsy One patient in static nail group had breakage of Interlock Bolt and nonunion & was treated with encirclage wiring and bone grafting. Same patient had shoulder stiffness and was relieved by vigorous physiotherapy. Two cases of delayed union were treated with bone grafting as second procedure. One case each in both groups had postop radial nerve paresis in the form of wrist drop, and recovered within 48 hours. It was not clear whether surgery or interscalene block was responsible as the recovery was too rapid. All preop existing radial nerve palsy recovered within six months with additional dynamic splint & physiotherapy. 14

15 OBSERVATIONS AND OUTCOMES The basic aim of managing diaphyseal Humeral fractures is to achieve union and restore function.in this study more stress was given on early recovery in form of union and function to prefracture state. Union was judged clinically by the lack of pain & tenderness at fracture site and assessment of serial radiographs for appearance of bridging calus and consolidation. Upper limb function was assessed as a whole using scoring system of the American Shoulder and Elbow Surgeons. Since antegrade nailing studies have shown more shoulder stiffness problems, emphasis was given on assessment of Constant Murlay score at the end of 6 months. The results have been graded on the basis of : 1] Time to union, 2] A.S.E.S. Score of upper limb function & 3] Constant-Murlay Shoulder Score Time to fracture union Points < 12 weeks to 18 weeks to 24 weeks to 30 weeks 04 More than 30 weeks 02 Nonunion 00 A.S.E.S. Score of upper limb function Points < Constant-Murlay Shoulder Score Points <

16 A maximum score of 30 points is possible and grading is as follows : Poor < 15 Satisfactory Good Excellent RESULTS : Results C H I L Nail Group Static Nail Group Excellent 10 [ 71%] 07 [ 47%] Good 04 [ 29%] 05 [ 33%] Satisfactory 02 [ 13%] Poor 01 [ 07%] Total 14 [ 100%] %] Excellent results seen in 71% patients in C H I L Nail group whereas 47%in Static Nail group. Good results seen in 29% cases in C H I L Nail group as against 33% in Static Nail group. In C H I L Nail group average time for appearance of calus was 12 weeks in fresh fracture cases and 18 weeks in nonunion cases treated with additional bone grafting. In Static Interlock Nail group average time for calus formation was 16 weeks in fresh fractures and 22 weeks in nonunion cases treated with additional bone grafting. 16

$oblique fracture but eventually united$

17 Delayed union was observed in Static Interlock group in two cases with short oblique fracture but eventually united with bone grafting as additional procedure. 17

18 One case in Static Interlock group had broken proximal interlock, loosening and nonunion as well as shoulder stiffness. This was revised with encirclage wiring and bone grafting. IMPLANT FAILURE NONUNION TREATED WITH ENCIRCLAGE WIRING & BONE GRAFTING 18

Since the recovery was rapid, it was not clear whether it was due to surgical insult or a prolonged interscalene block.

19 No implant failure in the form of breakage or bending was observed in Compression Interlock group. One case each in either groups had post op Radial Nerve paresis which recovered within 48 hours. Since the recovery was rapid, it was not clear whether it was due to surgical insult or a prolonged interscalene block. Other 3 cases of preop existing Radial Nerve injury recovered completely and steadily within 6 months with no residual deficit. Constant Shoulder score was better in C H I L Nail group [ 71%] excellent while [ 47%] in Static Interlock group. Overall complications were negligible and union was rapid in C H I L Nail group as compared to Static Interlock group. PREOP POSTOP 19

20 PREOP. POSTOP 3 MTHS POSTOP 20

$Compression Humerus Interlock Nail over it. Both the systems were studied en-vitro as well as Humerus fracture cases.$ The en-vitro study was done using 1] Sawed bamboo sticks, 2] Ex fixator units simulating intraoperative conditions of C

The en-vitro study was done using 1] Sawed bamboo sticks, 2] Ex fixator units simulating intraoperative conditions of C

Nail and Static Nail were used to fix sawed bamboo stick fragments.

21 DISCUSSION : This study was aimed at knowing the drawbacks of Static Humerus Interlock Nailing and advantages of Compression Humerus Interlock Nail over it. Both the systems were studied en-vitro as well as Humerus fracture cases. The en-vitro study was done using 1] Sawed bamboo sticks, 2] Ex fixator units simulating intraoperative conditions of C H I L Nail to study the bending strength of interlock bolts across specified length & 3] Cadaveric bones Both C H I L Nail and Static Nail were used to fix sawed bamboo stick fragments. With Static Interlock nail there was about 15 degree rotational instability as demonstrated in the pictures. The rotational instability is also appreciated in cadaveric studies. 21

Even with impaction before proximal interlock, there remained some distraction instability

pictures. Sawed bamboo sticks fixed with static I L Nail shows distraction instability.

22 Even with impaction before proximal interlock, there remained some distraction instability due to disparity between the size of interlock hole and bolt as is obvious from the pictures. Sawed bamboo sticks fixed with static I L Nail shows distraction instability. With Compression Interlocking both the rotational and distraction instabilities disappeared. For the drawback of interlock bolt bending or loosening and breakage of proximal capsule hole, the proximal end of nail was made 10 mm in diameter with capsule hole of 5 mm diameter. 22

The initial en-vitro experiments showed that the distal interlock bolt being spanned about 8 to 9 mm did not bend on

9 mm used to bend because of being spanned across 25 to 30 mm.

9 mm interlock bolt, it did not bend on compression with even 5 Nm torque driver force.

23 The initial en-vitro experiments showed that the distal interlock bolt being spanned about 8 to 9 mm did not bend on compression even the diameter was 3.9 mm. A proximal interlock bolt of 3.9 mm used to bend because of being spanned across 25 to 30 mm. However after expansion of proximal portion of nail to 10 mm and capsule hole to 5 mm to accommodate a 4.9 mm interlock bolt, it did not bend on compression with even 5 Nm torque driver force. This study was done using two ex-fix units holding the distal and proximal interlock bolts spanning desired distance as seen in the pictures. Distal I L Bolt spanned 9 mm. Proximal I L Bolt spanned 25 mm. En-vitro testing for bending strength of I.L.Bolt 23

$minimizing and compressing the fracture$

24 In cadaveric bone the C H I L Nail demonstrated a definite advantage of minimizing and compressing the fracture gap and achieve rotational stability as well. 24

$A series of 14 cases of fracture shaft Humerus treated with C H I L Nail was studied and compared with another series of 15 cases treated with Static Interlock Nail.$

25 Using a 4 Nm Torque Screw Driver prevented bending of proximal Interlock Bolt or breakage of implant. A series of 14 cases of fracture shaft Humerus treated with C H I L Nail was studied and compared with another series of 15 cases treated with Static Interlock Nail. There was no gross difference in number of cases as far as age group, sex, site of fracture, associated radial nerve injury & nail diameter are concerned. The difference in terms of percentage being obviously due to small study groups. There was significant difference in time taken for union. 8 cases [ 57%] in C H I L Nail group had s/o union in 12 weeks as against 4 cases [27%] in Static Locking Nail group. The average union period in fresh fracture group with C H I L Nail was 12 weeks as against 16 weeks with Static Locking Nail. In Non union group it was 18 weeks & 22 weeks respectively. 25

Patients in C H I L Nail group had consistent good to excellent shoulder function than Static Nail group. This may be attributed to a more stable fixation and resultant early exercise tolerance.

This can be attributed to 1] small group, 2] more strong proximal design 3] in-vitro exercise to minimize complications, & 4] more stable and rigid fixation leading to better pain relief and

26 Patients in C H I L Nail group had consistent good to excellent shoulder function than Static Nail group. This may be attributed to a more stable fixation and resultant early exercise tolerance. Comparatively complication rate was low in C H I L Nail group than Static Nail group. This can be attributed to 1] small group, 2] more strong proximal design 3] in-vitro exercise to minimize complications, & 4] more stable and rigid fixation leading to better pain relief and exercise tolerance. While fixing distal third non-unions, in that difficult zone, the C H I L Nail after compression used to give immediate and secure rotational and distraction stability. This concentric compression with availability of all around space for bone grafting was a distinct advantage over a plate. 26

27 CONCLUSION : Interlock Humerus Nailing has advantage of ease & minimal dissection over compression plating. However especially in humerus it lacks in compressibility and rotational stability as seen in en-vitro studies. Shoulder stiffness is another drawback. Compression interlocking has advantage of achieving compression at fracture site & rotational stability as well. Early mobilization is possible and can overcome the shoulder stiffness. Use of graduated Torque Screw Driver while achieving compression prevents possible bending of interlock bolt. Results in the present study show early union and lesser complications with Compression Humerus Interlock Nail as compared to Static Interlock Nail. However being a small study group & very few reported studies, more number of case studies by different surgeons is advisable. 27

28 REFERENCES : 1] Mückley T, Diefenbeck M, Sorkin AT, Beimel C, Goebel M, Bühren V. Results of the T2 humeral nailing system with special focus on compression interlock. Injury 2008 mar 39(3): ] Campbell s Operative orthopaedics 1998 ed. 3] Moran MC Distal interlocking during intramedullary nailing of humerus. Aug : 317 : ] Rockwood CA, Green DP, Bucholz RW Fractures in adults, 4 th ed : ] Ruf W, Pauly E - Interlocking nailing of the humerus. Unfallchirurg Jun e 1993 ; 96(6) : ] Russel TA, Taylor JC - Surgical technique manual - Russel Taylor humeral interlocking naik system, Smith and nephew Richards. 7] Tom EJ, Carsi D, Garcia C, Marco F - Treatment of pathologic frac tures of the humerus with Seidel nailing. Clin. Orthop May 350:51-5 8] Rommens PM, Kuechle R, Bord T, Lewens T, Engelmann R, Humeral nailing revisited Blum JInjury.2008 Dec;39(12): Epub 2008 Apr 15. 9] Mauch J, Renner N, Rikli D - Intramedullary nailing of humeral shaft fractures-- initial experiences with an unreamed humerus nail. Swiss Surg. 2000;6(6): ] Vécsei N, Kolonja A, Mousavi M, Vécsei V.-Intramedullary fixation of humerus shaft fractures. An analysis of complications of 2 implants with special reference to outcome after management with the unreamed humerus interlocking nail Wien Klin Wochenschr Aug 16;113(15-16):

The study of distal ¼ diaphyseal extra articular fractures of humerus treated with antegrade intramedullary interlocking nailing

$The study of distal ¼ diaphyseal extra articular fractures of humerus treated with antegrade intramedullary interlocking nailing$ 2018; 4(4): 46-50 ISSN: 2395-1958 IJOS 2018; 4(4): 46-50 2018 IJOS www.orthopaper.com Received: 01-08-2018 Accepted: 03-09-2018 Dr. Ankur Parikh Orthopaedics, Jehangir Hospital, Sassoon road, Pune, Dr.