Prospective Morphologic and Dynamic Assessment of Deep Flexor Tendon Healing in Zone II by High-Frequency Ultrasound: Preliminary Experience

Transcription

1 Musculoskeletal Imaging Original Research Puippe et al. High-Frequency Ultrasound ssessment of Deep Flexor Tendon Musculoskeletal Imaging Original Research Prospective Morphologic and Dynamic ssessment of Deep Flexor Tendon Healing in Zone II by High-Frequency Ultrasound: Preliminary Experience Gilbert D. Puippe 1 Nicole Lindenblatt 2 Ralph Gnannt 1 Pietro Giovanoli 2 Gustav ndreisek 1 Maurizio Calcagni 2 Puippe GD, Lindenblatt N, Gnannt R, Giovanoli P, ndreisek G, Calcagni M OJECTIVE. The purpose of this article is to prospectively evaluate early postoperative morphologic and functional changes after deep flexor tendon repair in zone II using ultrasound and to correlate findings from ultrasound with the clinical outcome. SUJECTS ND METHODS. Ten patients (mean age, 34 years; range, years) with 11 injured deep flexor tendons of the hand underwent surgical tendon repair. Postoperative tendon morphology was assessed with gray-scale and power Doppler ultrasound over a period of 3 months. Tendon excursion over the proximal interphalangeal joint was assessed by sonographic scar tracking. Correlation of ultrasound findings with clinical outcome was performed. RESULTS. lmost all repaired tendons exhibited a spindlelike shape after 1 week, of which 5% developed a normal shape after 12 weeks. persisting spindlelike shape over 3 months was associated with a significantly increased tendon excursion (p <.5) and a trend toward better active motion of the fingers (p =.56). Tendons with increased power Doppler signal showed a significantly better tendon excursion and active motion after 12 weeks (all p <.5). Tendon excursion measurements obtained by scar tracking showed excellent correlation (r =.84; p <.5) with total active finger motion. CONCLUSION. Preliminary data of this study indicate a better clinical outcome if a sutured tendon maintains a spindlelike shape and increased power Doppler signal. This might indicate a predominantly intrinsic healing pattern with reduced adhesion formation. Ultrasound morphology, power Doppler signal, and tendon excursion may be helpful tools to rate tendon healing and to establish individually modified rehabilitation protocols. Keywords: flexor tendon, intrinsic healing, outcome, prospective, ultrasound DOI:1.2214/JR Received March 21, 211; accepted after revision June 15, Department of Diagnostic and Interventional Radiology, Musculoskeletal Imaging Research Group, University Hospital Zurich, Raemistrasse 1, Zurich 891, Switzerland. ddress correspondence to G. D. Puippe (gilbert.puippe@usz.ch). 2 Division of Hand, Plastic, and Reconstructive Surgery, Department of Surgery, University Hospital Zurich, Zurich, Switzerland. WE This is a Web exclusive article. JR 211; 197:W111 W X/11/1976 W111 merican Roentgen Ray Society L acerations of finger flexor tendons are a frequent clinical problem [1]. Despite the establishment of early motion protocols after surgery, repairs in zone II remain a demanding task for hand surgeons mainly because of difficult gliding at the suture site and adhesion formation in the tendon sheath [2]. Previous studies reported rerupture rates of 4 1%, adhesion formation requiring tenolysis in 15% of the cases, and stiff interphalangeal joints in up to 5% of cases [3]. Therefore, it has to be admitted that treatment regimens, both surgery and postoperative mobilization, for these injuries are not yet optimal. In recent years, several in vitro and in vivo studies have identified factors that influence the clinical outcome after flexor tendon repair. oth the kind of trauma (e.g., clean-cut vs crush injury) and the amount of traumatized soft tissue have an influence on the outcome, especially on the amount of scar and adhesion formation [3, 4]. The treatment objective for patients with intrasynovial flexor tendon lacerations remains to achieve a primary tendon repair of enough tensile strength that allows an immediate postoperative mobilization protocol to prevent the formation of adhesions [4 6]. With the development of stronger suture material and four- or even six-strand techniques, postoperative hand rehabilitation has shifted from pure passive motion to early active motion protocols, leading to some improvement in the functional results [7, 8]. Nevertheless, the postoperative assessment of the tendon s healing is still limited to wound inspection and functional examination. Early changes of the tendon itself (e.g., shape or perfusion changes, bulkiness, or gapping at the repair site), as well as postsurgical changes of the synovial sheath and its adjacent subcutaneous and neurovascular structures, cannot be assessed. High-frequency ultrasound is increasingly used in the diagnosis of many different hand abnormalities because it is a noninvasive, repeatable, and reasonably inex- W111 JR:197, December 211

2 pensive diagnostic tool. The use of ultrasound imaging in the postoperative course is mainly constrained by the fact that, to our knowledge, there are no data on the sonographic appearance of a sutured tendon in the various phases of the healing process. Furthermore, there is little information available in the literature on the real amount of motion at the suture site [9]. Therefore, it was the purpose of this study to prospectively analyze postoperative morphologic and functional changes during the healing process of the sutured flexor digitorum profundus (FDP) tendon in zone II of the fingers with high-frequency ultrasound over a period of 3 months and to correlate the sonographic findings with the postoperative clinical function. This analysis was performed to track changes of the tendon morphology and its adjacent structures, with the aim of identifying a morphologic pattern of the healing process. dditionally, the study was aimed to dynamically assess tendon motion at the suture site using sonographic scar tracking. Subjects and Methods The study protocol was approved by the local ethical committee and institutional review board. Written informed consent was obtained from each patient. Inclusion and Exclusion Criteria Included in the study were men and women older than 18 years presenting at the emergency unit with a fresh traumatic laceration of an FDP tendon in zone II of more than 5% of the cross-sectional area, with or without injury of the flexor digitorum superficialis (FDS) tendon, digital arteries, or nerves. Exclusion criteria were crush injury, additional fractures, subtotal or total amputation, a history of connective tissue disorders, collagenoses, or rheumatoid disease. Patients and Injury Characteristics From pril to October 21, 1 consecutive patients (three women and seven men) with a total of High-Frequency Ultrasound ssessment of Deep Flexor Tendon TLE 1: Outline of Study Protocol Follow-Up Examination No. Days fter Surgery Sonography and Clinical Examination Healthy and operated site Operated site 3 14 Operated site 4 21 Operated site 5 35 Operated site 6 7 Operated site 7 84 Operated site Note Initial sonography and clinical examination were performed between the first and third day after surgery. During the same session, the corresponding uninjured finger on the contralateral side was examined. Further follow-up examinations took place at the respective time points over a period of 3 months. 11 injured FDP tendons in zone II met the inclusion criteria and were enrolled in the study. Follow-up examinations were performed according to the study protocol (Table 1). The mean age was 47 years for women (age range, years) and 29 years for men (age range, years). Five men had smoking as a single cardiovascular risk factor (mean [± SD], 5.4 ± 6.8 pack-years). No patient had a history of diabetes, hypertension, dyslipidemia, anticoagulation, or immunosuppressive medication. Overview of characteristics, frequency, and distribution of finger injuries and surgically repaired structures are displayed in Tables 2 and 3. s a control, the corresponding uninjured tendon on the contralateral side was used. ll patients had no previous injuries of the tendon used as a control. Surgical Tendon Repair Surgical repair was performed in a standardized fashion in axillary plexus anesthesia and brachial tourniquet ischemia by staff surgeons of our unit. oth of the neurovascular bundles were identified. Repair of the FDP tendon was achieved by a four-strand core suture with a 4/ polyester braid containing a long chain polyethylene core (FiberWire, rthrex) followed by a circumferential polypropylene 6/ epitendinous locking suture (Prolene, Johnson & Johnson Medical). ll FDS tendons were repaired in the same fashion, if necessary. Injuries of the neurovascular bundle, if present, were repaired with 9/ monofilament pol- TLE 2: Overview of Characteristics, Frequency, and Distribution of Finger Injuries in 1 Patients and 11 Digits Injury Distribution Frequency, % (No. of Digits/Total) Injured digit Digit II 45.5 (5/11) Digit III 9.1 (1/11) Digit IV 36.4 (4/11) Digit V 9.1 (1/11) Injured tendon FDP tendon only 9.1 (1/11) FDP tendon and both FDS tendons 63.6 (7/11) FDP tendon and ulnar FDS tendon 18.2 (2/11) FDP tendon and radial FDS tendon 9.1 (1/11) Injured artery No artery injured 81.8 (9/11) Radial and ulnar artery 9.1 (1/11) Radial artery 9.1 (1/11) Ulnar artery (/11) Injured nerve No nerve injured 36.4 (4/11) Radial and ulnar nerve 9.1 (1/11) Radial nerve 9.1 (1/11) Ulnar nerve 45.5 (5/11) Cause of trauma Cut by knife 36.4 (4/11) Cut by glass 54.5 (6/11) Cut by saw 9.1 (1/11) Note FDP = flexor digitorum profundus, FDS = flexor digitorum superficialis. JR:197, December 211 W1111

3 Puippe et al. TLE 3: Overview of Frequencies and Distribution of Surgically Repaired natomic Structures in 1 Patients and 11 Digits natomic Structure Distribution Frequency, % (No. of Digits/Total) Sutured tendon FDP tendon only 9.1 (1/11) FDP tendon and 1 string of FDS tendon 36.4 (4/11) FDP tendon and 2 strings of FDS tendon 54.5 (6/11) Sutured artery No suture 81.8 (9/11) Suture of 1 artery 18.2 (2/11) Sutured nerve No suture 36.4 (4/11) Suture of 1 nerve 54.5 (6/11) Suture of 2 nerves 9.1 (1/11) Note FDP = flexor digitorum profundus, FDS = flexor digitorum superficialis. yamide (Nylon, S&T). In two cases, the 3 and 4 pulley, respectively, had to be incised to perform tendon repair. Free gliding of the sutured tendon through the full range of motion of all finger joints was verified in all patients at the end of the surgery. For postoperative immobilization, a fourfinger palmar cast was applied in 2 flexion of the wrist and intrinsic plus position of the finger joints. Postoperative Rehabilitation Protocol ll patients received postoperative hand rehabilitation by a certified hand therapist from our unit using a modified Kleinert protocol. fourfinger thermoplastic dorsal lower arm splint with the wrist flexed in 3, the metacarpophalangeal joints positioned in 7 of flexion, and of flexion of the proximal interphalangeal (PIP) and distal interphalangeal (DIP) joints was fitted within the first 3 days after tendon suture, combined with a rubber band for home exercises. In the first 3 weeks, passive mobilization of the finger was performed combined with place-and-hold exercises. t week 4, active motion without resistance was started. Increasing load was added after 8 weeks. Full strength load was reached after 12 weeks. Clinical ssessment of Finger Function Wound conditions, the presence of edema, as well as pain at movement and at rest were noted at every rehabilitation session. Postoperative total active range of motion (TM) was calculated according to the method of Strickland and Glogovac [1], which is defined as the sum of the active range of motion of the DIP and PIP joints. Ultrasound Protocol ll ultrasound examinations were performed by one of two radiologists (both with 3 years experience in musculoskeletal ultrasound). Fingers were examined with the hand placed in a customized dorsal wrist splint (Fig. 1). This brace guaranteed reproducible placement of the fingers at every follow-up Fig year-old woman without trauma of hand., Set-up for ultrasound examination. Hand was placed in customized dorsal splint with wrist in 7 of flexion, metacarpophalangeal joints in 4 of flexion, and proximal interphalangeal and distal interphalangeal (DIP) joints in., Deep flexor tendon excursion was measured over suture site during passive flexion of DIP joint ( 45 ). ultrasound examination without compromising the tendon suture. Ultrasound imaging was performed with an ultrasound unit (iu22 Ultrasound System, Philips Healthcare) with a linear high-frequency hockey-stick probe of 15 MHz (L15 7io roadband Compact Linear rray Transducer, Philips Healthcare). 1-mm-thick aqueous coupling medium for diagnostic ultrasound (Sonarid, Geistlich Pharma) was used. Each examination consisted of a standard gray-scale ultrasound of the tendon in both longitudinal and transverse planes. Duplex ultrasound in a transverse plane was used to show arterial pulse curve in the digitals arteries (Fig. 2). Power Doppler ultrasound in a longitudinal plane was performed to visualize vascularization of the tendon (Fig. 3). Color gain adjustment was calibrated on the corresponding healthy side, in a way that no signal was visible on the cortical bone dorsal to the tendon. Transducer pressure was minimized in order not to compress the vasculature. Dynamic imaging of the tendon movement at the suture site was performed during 45 of passive flexion at the level of the DIP joint with the ultrasound probe fixed in a longitudinal plane at the level of the suture. Images were stored as short cine loops. Image nalysis Gray-scale ultrasound images were systematically analyzed qualitatively and quantitatively by two radiologists in consensus, according to the following algorithm: shape, echogenicity of stumps, stump adaption, maximal anteroposterior diameter at the level of the suture, and soft-tissue changes. The amount of tendon edema was estimated by dividing the diameter of the tendon at the suture site through the diameter of the healthy tendon of contralateral healthy finger. n artery with an arterial pulse wave curve was defined to be patent. Power Doppler was correlated with the corresponding healthy finger and was graded semiquantitatively (i.e., normal means equal to the healthy side and with increased signal intensity). Finally, the excursion of FDP tendon suture was analyzed by thread-and-scar tracking of the hyperechogenic signal of the fiber wire core suture and later on of the scar (Fig. 4). FDP tendon excursion measurement was performed using the PCS software (Impax ES DS 3, gfa HealthCare). The first image of the acquired cine loop showed the position of the suture with PIP and DIP in of flexion. The distance between the cursor ( of flexion) and the endpoint of the suture (45 of flexion) was determined. Statistical nalysis Descriptive statistics of injury and surgery characteristics were performed. For correlation analysis, the Spearman correlation coefficient was calculated. correlation coefficient above.7 or W1112 JR:197, December 211

4 High-Frequency Ultrasound ssessment of Deep Flexor Tendon Fig year-old woman after flexor tendon repair of digit II of right hand., Twenty-one days after surgery, thin vasculature within tendon (arrows) can be detected with power Doppler ultrasound., Power Doppler ultrasound 7 days after surgery without any signal within tendon (arrowheads). Fig year-old woman 35 days after deep flexor tendon repair of digit II of right hand. Duplex ultrasound in transverse plane with arterial pulse wave of ulnar digit artery shows patency of this vessel. below.7 was set to be relevant. The t test or the Mann-Whitney rank sum test, depending on data distribution, was used to evaluate differences concerning power Doppler signal intensity and tendon shape. The significance level was set at.5 with a confidence level of 95%. Values are given as means ± standard error of the mean. Results Tendon Morphology During the Healing Process etween days 1 and 3, 25% of all tendons exhibited a spindlelike appearance, which changed until the second visit on days 5 7, where most tendons showed a spindlelike shape (Fig. 5). fter 12 weeks, 5% of all tendons presented a normal shape, whereas 5% maintained a spindlelike shape (Figs. 6 and 7). Gapping of 7 mm occurred in one tendon suture, whereas all other sutures showed exact adaption of the stumps. The echogenicity of the stumps in the first week after surgery was inhomogeneous hypoechogenic in more than 9% of the cases. The echogenicity changed during the healing course toward more hyperechogenic structures within the suture site. Three months after surgery, 27% of tendons exhibited an inhomogeneous hyperechogenic structure (Fig. 8). In all ultrasound examinations, the core suture could be identified as two parallel orientated hyperechogenic lines resembling a railway track (Fig. 9). The tendon diameter at the suture site was increased by 1.6-fold at day 3, showed a maximum after 3 5 weeks, and regressed slightly until 12 weeks, when compared with the corresponding healthy side (Fig. 1). Power Doppler ultrasound showed increased signal compared with the healthy side in about 25% of all tendons at days 1 3. t day 14, more than 5% of all tendons had increased signal intensity. t the final visit after 3 months, 4% of all tendons still were found to be hyperperfused (Fig. 11). Power Doppler perfusion did not correlate with nicotine abuse or artery or nerve injury. Dynamic ssessment of Tendon Movement Excursion of the FDP tendon was, on average, 1.5 ±.3 mm at day 3 and steadily increased to 2. ±.42 mm after 3 months (p =.2; 95% CI, ) (Fig. 12). The mean TM after 3 months amounted to 114 ± 13, denoting a fair outcome. The calculated Spearman correlation coefficient (.84; p <.5) showed a relevant correlation between FDP tendon excursion and postoperative TM. The association between FDP tendon excursion and active range of motion in the DIP joint only showed a moderate correlation (Spearman correlation coefficient,.65; p <.5). Smoking did not significantly influence power Doppler signal and the shape of the tendon or postoperative FDP tendon excursion and TM after 3 months. persisting spindlelike shape of the healing site after 12 weeks corresponded to significantly increased FDP tendon excursion Fig year-old man 7 days after repair of deep flexor tendon of digit II of left hand. Schematic illustration of thread-and-scar tracking sequence. Three fused images are arranged vertically with changing position of constantly appearing hyperechogenic point within scar (stars) at, 2, and 45 of passive flexion in distal interphalangeal (DIP) joint at day 7. Δx represents amount of deep flexor tendon excursion in millimeters during 45 of passive motion in DIP joint. JR:197, December 211 W1113

5 Puippe et al. (2.86 ±.61 mm vs 1.14 ±.27 mm; p <.5; 95% CI,.2.35). In line with this, there was a trend toward a significant increased TM of the interphalangeal joints in these patients (139 ± 16 vs 92 ± 18 ; p =.56). In patients with a persistent spindlelike shape, the TM was good, in contrast to a poor outcome in patients with a normal tendon structure (Figs. 13 and 13). Furthermore, tendons with a persisting increased power Doppler signal exhibited a significantly better FDP tendon excursion at 3 months (3.13 ±.7 mm vs 1.25 ±.6 mm; p <.5; 95% CI, 3.33 to.41). This was also reflected in a significantly better TM after 3 months (151 ± 12 vs 92 ± 15 ; p <.5; 95% CI, 18 to 11), which is graded as excellent according to Strickland and Glogovac [1] (Figs. 13C and 13D). Frequencies of Tendon Shapes (%) Normal Time fter Surgery (d) Spindle Fig. 5 Graph shows changes of tendon s shape throughout follow-up period of 84 days as percentage for each of two categories (spindle or normal). In most tendons, spindlelike structure starts to develop after 5 7 days. Fig year-old man 7 days after tendon repair of digit III of left hand., On gray-scale ultrasound of deep flexor tendon in longitudinal plane, core suture with concomitant fibrous tissue can still be depicted as longitudinally orientated hyperechogenic stripes (arrow)., Contours of same sutured tendon (broken lines) show spindlelike appearance of tendon. Fig year-old man after tendon repair of digit II of left hand., Fourteen days after surgery, contour of tendon exhibits spindlelike shape (broken lines). etween deep flexor tendon and volar aspect of middle phalanx, small postoperative fluid collection (star) can be depicted., Three months after surgery, same tendon now shows normal shape (broken lines). etween deep flexor tendon and volar aspect of middle phalanx, hyperechogenic tissue (star) is present, most likely representing scar tissue. Tendon gliding and postoperative total active range of motion was poor in this patient because of restrictive adhesions between deep flexor tendon and scar tissue. 84 Discussion Even though the concept of early motion protocols after flexor tendon repair has revolutionized tendon surgery in the last century, clinical function often is far from satisfactory [3, 11]. The economic burden of long periods of absence from work is obvious, and the quest for an improvement in rehabilitation protocols must continue. The goals of a postoperative motion program are to disrupt or prevent adhesions that restrict tendon motion and to prevent joint stiffness [3]. The concept of primary intrinsic tendon healing has been validated experimentally and clinically in studies over the past 25 years [12, 13]. However, little is still known about the actual processes within the tendon sheath. To improve postoperative rehabilitation protocols and to adjust these to the individual needs of patients, tools to identify the pattern of tendon healing must be established. One aim of the present study was to evaluate early morphologic changes after tendon repair to identify a sonographic pattern of the healing process. In regard to tendon shape, we identified two patterns. lthough most tendons had a spindlelike appearance until 3 weeks postoperatively, about half of all tendons developed a normal shape after 3 months. Interestingly, a spindlelike appearance and a persistently increased power Doppler signal were associated with a significantly better FDP tendon excursion after 3 months. This may suggest a persisting metabolic healing activity and might indicate a predominantly intrinsic healing pattern, resulting in fewer adhesions within the synovial sheath. When extrinsic healing predominates, adhesions between the tendon and its surrounding tissues form, whereas intrinsic healing will result in fewer and less rigid adhesions [14]. Tendon healing involves an inflammatory phase from 48 to 72 hours after repair, a fibroblastic or collagen-producing phase from 5 days to 4 weeks, and a remodeling phase, which continues until 4 months [14]. These phases of healing may correspond to changes in echogenicity, as found in our study. In the early inflammatory and proliferative phases, tendons appeared predominantly hypoechogenic, which can be explained by the high content of blood vessels and edema. In the W1114 JR:197, December 211

6 High-Frequency Ultrasound ssessment of Deep Flexor Tendon remodeling phase, the increase of organized collagen fibers lead to a higher echogenicity within the tendon. The second aim of the study was the dynamic assessment of tendon motion at the suture site. Initially, the use of fiber wire core Frequencies of Echogenicity of Tendon (%) Inhomogeneous hypoechogenic Homogeneous isoechogenic Inhomogeneous hyperechogenic sutures and later on, the forming scar within the tendon made suture tracking possible in a noninvasive fashion using high-frequency ultrasound. This subsequently enabled the measurement of FDP tendon movement at the level of the suture. Previous studies Time fter Surgery (d) Fig. 8 Changes of echogenicity over time. ll tendons appear hypoechogenic in first week after tendon repair and become more hyperechogenic during healing process after 21 days used invasive methods to determine flexor tendon movement [15 18]. It has been observed that DIP joint motion produces excursion of the FDP tendon of 1 2 mm per 1 of joint flexion, whereas each 1 of PIP joint flexion results in excursion of both the FDS and FDP tendons of about 1.5 mm [9, 19]. study by Silfverskiöld et al. [2] almost 2 years ago using intratendinous metal markers and postoperative x-ray found a substantial decrease in the movement of tendon repairs compared with normal movement. The motion of a repaired FDP tendon is reduced to an average of.3 mm per 1 of DIP joint flexion. PIP joint motion is better retained, with about 1.3 mm of FDS and FDP tendon excursion per 1 flexion after repair. Our results are in line with the previous literature. fter 45 of passive flexion of the DIP joint, the excursion of the FDP tendon at the level of the PIP joint was found to be 1.5 ±.3 mm within the first 3 days and steadily increased to 2. ±.4 mm 3 months postoperatively. In another study [21], tendon excur- C D G E Fig year-old woman after flexor tendon repair of digit II of right hand. G, Images of all seven follow-up examinations. On all images, proximal part of tendon is on right, and distal part is on left image side., Initial investigation 3 days after surgery displays hypoechogenic tendon containing core suture, which can be depicted as two hyperechogenic parallel orientated stripes (arrowheads). Proximal interphalangeal joint is marked (star). Of note, small subcutaneous hematoma is found., Seven days after surgery, increased swelling and spindlelike appearance on level of suture (arrows) are seen. C, Increased hyperechogenic echo (arrows) on level of suture is seen after 14 days. D, t day 21 after surgery, core suture (arrowheads) still can be depicted. E, Tendon at day 35 after surgery. Tendon still shows spindlelike configuration (broken lines) on level of suture (arrowhead). F, Persisting spindle shape 7 days after surgery with increased echogenicity on level of core suture (arrowhead). Subcutaneous hematoma has completely regressed. G, fter 84 days, still slight spindlelike configuration of thickened tendon can be detected (broken lines). Echogenicity remains slightly increased. Remnant suture material is displayed as hyperechogenic dots within tendon (arrowheads). F JR:197, December 211 W1115

7 Puippe et al. Relative Thickness of Sutured Tendons Time fter Surgery (d) Fig. 1 Ratios of diameter of sutured tendon to diameter of healthy tendon as parameter of relative thickness of sutured tendon. Values are given as means with 95% CIs. Excursion of Deep Flexor Tendon (mm) Frequencies of Power Doppler Signal (%) Signal normal/equal to healthy side Increased signal Not diagnostic because of image artifacts Time fter Surgery (d) Fig. 11 Frequencies of three power Doppler categories over follow-up time of 3 months. Most tendons exhibit increased power Doppler signal in period of 14 days after suture Time fter Surgery (d) Fig. 12 Deep flexor tendon excursion over observation period of 84 days. Values are given as means with 95% CI sion was measured by using a color Doppler imaging system. This method seems to be a feasible possibility but remains too complicated for routine use. The length of follow-up affects the recorded outcome of the flexor tendon repair. Flexor tendon healing and collagen remodeling usually take longer than 2 3 months, and correction of interphalangeal joint contracture may require even longer. The outcome of flexor tendon repair should be determined not earlier than 3 months after surgery [3]. Of the various methods of evaluating the outcome after flexor tendon repair, we applied the criteria according to Strickland and Glogovac [1], which are defined by the measured TM (degrees) and the percentage of functional return. TM is defined as the sum of the active range of motion of the DIP and PIP joints. Outcome is rated as excellent (TM, > 15 ; functional return, 85 1%), good (TM, ; functional return, 7 84%), fair (TM, ; functional return, 5 6%), and poor (TM, < 9 ; functional return, 49%), respectively. Interestingly, when looking at the TM in patients with spindlelike tendon shape and increased power Doppler perfusion separately, we found goodto-excellent function in these patients. There are several limitations to this study. One of the major limitations is that only 11 tendons were assessed. Therefore, results of this study should be taken as a preliminary experience with this technique. Findings of this study must be verified in further studies with a larger number of patients. second limitation is that late results of 6 and 12 months postoperatively could not be achieved because patients could not be called back for late follow-up examinations. Late outcome would be particularly interesting to judge whether early sonographic findings correlate with late clinical outcome. Third, intra- and interobserver agreement were not assessed in this study because not all patients were individually and independently examined by both readers at each follow-up examination. ecause ultrasound imaging remains a highly investigator-dependent modality, future studies are required to test intra- and interreader agreement of this new technique. Furthermore, it remains unclear why some patients showed more perfusion of the tendon and a different healing pattern than others. Finally, it is yet not possible to measure the excursion of a healthy tendon by this method. This reduces the possibilities to compare postoperative tendon gliding to the healthy side. W1116 JR:197, December 211

8 TM (Degree of Motion) TM (Degree of Motion) Shape Normal Normal Power Doppler Intensity However, the major aims of surgical treatment of flexor tendon lacerations remain primary tendon repair of adequate strength to enable early postoperative motion protocols [6]. Therefore, it is highly desirable to develop a method to estimate the progress of tendon healing in the postoperative period to adjust the amount of finger motion on an individual basis. FDP tendon excursion measurement according to our protocol seems to be an easy and reliable method. n increase in FDP tendon excursion detected by ultrasound may be a helpful additional tool for measuring the outcome. Moreover, a continuously dynamic assessment of flexor tendon gliding and excursion may help to identify forming adhesions. Preliminary data from our study have shown that the shape or perfusion of a tendon may be a useful tool in estimating the healing process. 1995; 3:44 54 High-Frequency Ultrasound 4 ssessment of Deep Flexor Tendon 6. Strickland JW. Development of flexor tendon surgery: twenty-five years of progress. J Hand Surg * * m 2; 25: Chesney, Chauhan, Kattan, Farrokhyar F, Thoma. Systematic review of flexor tendon rehabilitation protocols in zone II of the hand. Plast 2 Reconstr Surg 211; 127: Trumble TE, Vedder N, Seiler JG 3rd, Hanel DP, Diao E, Pettrone S. Zone-II flexor tendon repair: a 1 randomized prospective trial of active place-andhold therapy compared with passive motion therapy. J one Joint Surg m 21; 92: Horibe S, Woo SL, Spiegelman JJ, Marcin JP, Shape Shape Shape Gelberman RH. Excursion of the flexor digitorum Spindle Normal Spindle profundus tendon: a kinematic study of the human and canine digits. J Orthop Res 199; 8: Strickland JW, Glogovac SV. Digital function following flexor tendon repair in Zone II: a compari- 5 * * son of immobilization and controlled passive motion techniques. J Hand Surg m 198; 5: Kleinert HE, Kutz JE, tasoy E, Stormo. Primary repair of flexor tendons. Orthop Clin North 3 m 1973; 4: Increased Power Doppler Intensity C Fig. 13 Measurements of tendon movement after surgery. D, Graphs show total active range of motion (TM) measured according to Strickland and Glogovac [1] ( and C) and deep flexor tendon excursion of tendons ( and D) with persisting spindle shape ( and ) and increased power Doppler signal (C and D) within tendon after 3 months. In these tendons, significantly better tendon movement and finger movement were apparent after 3 months. Values are given as means ± standard error of the mean (*p <.5 vs shape normal; # p <.5 vs normal power Doppler intensity). Deep Flexor Tendon Excursion (mm) Deep Flexor Tendon Excursion (mm) 2 1 Normal Power Doppler Intensity Increased Power Doppler Intensity cknowledgment We thank Christine Meier and the Hand Therapy Team of the University Hospital of Zurich for performing postoperative rehabilitation therapy and their excellent participation in the assessment of postoperative hand function. References 1. Hill C, Riaz M, Mozzam, rennen MD. regional audit of hand and wrist injuries: a study of 4873 injuries. J Hand Surg [r] 1998; 23: Coats RW 2nd, Echevarria-Oré JC, Mass DP. cute flexor tendon repairs in zone II. Hand Clin 25; 21: Tang J. Clinical outcomes associated with flexor tendon repair. Hand Clin 25; 21: oyer MI. Flexor tendon biology. Hand Clin 25; 21: Strickland JW. Flexor tendon injuries. Part I. Foundations of treatment. J m cad Orthop Surg D 12. Gelberman RH, Vandeberg JS, Manske PR, keson WH. The early stages of flexor tendon healing: a morphologic study of the first fourteen days. J Hand Surg m 1985; 1: Gelberman RH, Woo SL, Lothringer K, keson WH, miel D. Effects of early intermittent passive mobilization on healing canine flexor tendons. J Hand Surg m 1982; 7: Strickland JW. The scientific basis for advances in flexor tendon surgery. J Hand Ther 25; 18:94 11, quiz Gelberman RH, otte MJ, Spiegelman JJ, keson WH. The excursion and deformation of repaired flexor tendons treated with protected early motion. J Hand Surg m 1986; 11: Hagberg L, Selvik G. Tendon excursion and dehiscence during early controlled mobilization after flexor tendon repair in zone II: an x-ray stereophotogrammetric analysis. J Hand Surg m 1991; 16: Wehbe M, Hunter JM. Flexor tendon gliding in the hand. Part I. In vivo excursions. J Hand Surg m 1985; 1: Wehbe M, Hunter JM. Flexor tendon gliding in the hand. Part II. Differential gliding. J Hand Surg m 1985; 1: McGrouther D, hmed MR. Flexor tendon excursions in no-man s land. Hand 1981; 13: Silfverskiöld KL, May EJ, Tornvall H. Flexor digitorum profundus tendon excursions during controlled motion after flexor tendon repair in zone II: a prospective clinical study. J Hand Surg m 1992; 17: Soeters JN, Roebroeck ME, Holland WP, Hovius SE, Stam HJ. Reliability of tendon excursion measurements in patients using a color Doppler imaging system. J Hand Surg m 24; 29: JR:197, December 211 W1117