The terminal tendon of the digital extensor mechanism: Part II, kinematic study

PURPOSE: To conduct kinematic analyses of both intact and sectioned terminal tendon (TT) of multiple fingers in the hand. METHODS: The TTs of 36 fresh-frozen cadaveric digits were used in this study. TT excursion was assessed along with the influence on proximal joint motion. The influence of TT lengthening and shortening on distal interphalangeal (DIP) joint motion were investigated. RESULTS: TT excursion averaged 1 mm at the DIP joint and was influenced by the proximal interphalangeal (PIP) joint but not the position of other joints in the hand and wrist. The greatest degree of DIP joint motion averaged 86 degrees when the PIP joint was in full flexion, whereas the least motion averaged 45 degrees when this joint was in neutral position. Lengthening of the TT resulted in angular deformity at the DIP joint. Average flexion deformities reached 25 degrees at 1 mm, 36 degrees at 2 mm, 49 degrees at 3 mm, and 63 degrees at 4 mm of lengthening. The middle finger showed the greatest flexion deformity, followed by the ring, small, and index fingers. Shortening the TT by as little as 1 mm resulted in difficult tendon repair because of excessive tension and minimal or no DIP joint flexion was obtained. CONCLUSION: Only DIP and PIP joints affect TT excursion; hence these are the main joints to be immobilized to protect TT repair. The middle finger TT showed the least tolerance to lengthening with potential for mallet deformity. Joint flexion deformity is proportional to tendon lengthening. Only 1 mm of TT lengthening results in approximately 25 degrees of DIP joint extension lag, and 4 mm of TT lengthening results in DIP joint flexion deformity greater than 60 degrees . Even 1 mm of TT shortening will seriously restrict DIP joint flexion.     

Correction of the severe nonrheumatoid chronic boutonnière deformity with a modified Matev procedure

Twenty consecutive patients with severe chronic nonrheumatoid deformities were treated with a modification of the Matev procedure. Fourteen of the 20 had normal passive range of motion preoperatively, with the proximal interphalangeal joints lacking 59 degrees of active extension and the distal interphalangeal joints hyperextended 17 degrees. In the other six patients with PIP contracture at the time of reconstruction, PIP joints lacked 68 degrees of active extension and the DIP joints were hyperextended 13 degrees. Follow-up averaged 8 months, and at that time the patients with no contracture had an average of 14 degrees/96 degrees of active motion at the PIP joint and 9 degrees/59 degrees of motion at the DIP joint. The group with contracture had an average of 21 degrees/80 degrees of active motion at the PIP and 13 degrees/41 degrees of motion at the DIP joint. There were 85% good or satisfactory outcomes in the group without contracture and 67% good or satisfactory outcomes in the group with contracture.     

Correction of the severe nonrheumatoid chronic boutonnière deformity with a modified Matev procedure.

Twenty consecutive patients with severe chronic nonrheumatoid deformities were treated with a modification of the Matev procedure. Fourteen of the 20 had normal passive range of motion preoperatively, with the proximal interphalangeal joints lacking 59 degrees of active extension and the distal interphalangeal joints hyperextended 17 degrees. In the other six patients with PIP contracture at the time of reconstruction, PIP joints lacked 68 degrees of active extension and the DIP joints were hyperextended 13 degrees. Follow-up averaged 8 months, and at that time the patients with no contracture had an average of 14 degrees/96 degrees of active motion at the PIP joint and 9 degrees/59 degrees of motion at the DIP joint. The group with contracture had an average of 21 degrees/80 degrees of active motion at the PIP and 13 degrees/41 degrees of motion at the DIP joint. There were 85% good or satisfactory outcomes in the group without contracture and 67% good or satisfactory outcomes in the group with contracture.     

Correction of swan neck deformity in rheumatoid arthritis using a new lateral extensor band technique

Swan neck deformity is a progressive and disabling condition that commonly affects rheumatoid arthritic hands. During a 4-year period, 101 fingers in 43 patients had this deformity corrected using a new procedure combining the distally based extensor lateral band technique described by Littler and the flexor digitorum superficialis (FDS)-palmar plate pulley introduced by Zancolli. The ranges of motion of the metacarpophalangeal, proximal interphalangeal (PIP) and distal interphalangeal (DIP) joints were assessed pre-operatively and 12 months after surgery. An average PIP joint hyperextension of -13.3 degrees was converted to +13.4 degrees . The ranges of motion of the proximal and DIP joints were significantly different (Student's t-test). No patient suffered recurrence of the deformity during an average follow-up of 20 months. This new technique improves some unappealing aspects of previous techniques and provides a stable and reliable correction of swan neck deformity.     

Results of proximal interphalangeal joint release for flexion contractures: midlateral versus palmar incision

Forty-two patients (45 fingers) were retrospectively reviewed after operative release of flexion contractures of the proximal interphalangeal (PIP) joint. The release was accomplished through a palmar incision in 19 fingers, usually followed by skin coverage using a lateral transposition flap. A midlateral incision was used in 26 fingers. The 2 groups were comparably matched with respect to degree of contracture and demographic characteristics. Active range of motion (ROM) was measured before and after surgery. In the palmar incision group, preoperative median PIP joint ROM was 60 degrees to 90 degrees (extension/flexion) and 30 degrees to 90 degrees at the 3-year follow-up examination. In the midlateral incision group, preoperative median PIP joint ROM was 50 degrees to 90 degrees (extension/flexion) and 0 degrees to 90 degrees at the 1.5-year follow-up examination. The improvement in ROM was significantly better in the midlateral incision group than in the palmar incision group.     

Current concepts: mallet finger

Loss of the extensor mechanism at the distal interphalangeal (DIP) joint leads to mallet finger also known as baseball finger or drop finger. This can be secondary to tendon substance disruption or to a bony avulsion. Soft tissue mallet finger is the result of a rupture of the extensor tendon in Zone 1, and a bony mallet finger is the result of an avulsion of the extensor tendon from the distal phalanx with a small fragment of bone attached to the avulsed tendon. Mallet finger leads to an imbalance in the distribution of the extensor force between the proximal interphalangeal (PIP) and DIP joints. If left untreated, mallet finger leads to a swan neck deformity from PIP joint hyper extension and DIP joint flexion. Most mallet finger injuries can be managed non-surgically, but occasionally surgery is recommended for either an acute or a chronic mallet finger or for salvage of failed prior treatment.     

Management of a proximal interphalangeal joint fracture dislocation with a compass proximal interphalangeal joint hinge and therapy: a case report.

The purpose of this report is to describe the management of a chronic proximal interphalangeal (PIP) joint fracture dislocation in a 46-year-old computer programmer. Twenty days following injury, a right ring finger volar plate arthroplasty was performed, loose fracture fragments were excised, and a Compass PIP joint hinge was applied. The hinge was locked at 10 degrees to 15 degrees extension and held in this position for 8 days. On postoperative day 8, hand therapy was initiated. Many challenges were encountered. Insurance constraints required the patient to change therapists. The device frame cracked. The patient developed a PIP joint contracture with extensor lag. Despite these obstacles, the patient achieved a successful outcome, returning to normal pain-free use with grip strength at 87% of that of the uninvolved hand. At discharge, active range of motion was 12 degrees/100 degrees at the PIP joint and 0 degrees/40 degrees at the DIP joint. Passive extension was 0 degrees. At 6 months postoperatively, active range of motion was 0 degrees/105 degrees at the PIP joint and 0 degrees/60 degrees at the DIP joint. This case demonstrates the need for closely supervised postoperative therapy that includes good communication between providers, ongoing patient education, and close monitoring of range of motion.     

Zone I flexor tendon rehabilitation with limited extension and active flexion.

This article describes an immediate active motion protocol for primary repair of zone I flexor tendons treated with tendon to tendon, or tendon to bone repair, and reviews clinical results. A rehabilitation protocol is proposed that will limit excursion of the zone I repair by blocking full distal interphalangeal (DIP) extension and by applying controlled active tension to both the unrepaired flexor digitorum superficialis (FDS) and the repaired flexor digitorum profundus (FDP). The rehabilitation technique utilized a dorsal protective splint with a relaxed position of immobilization with 30 degrees of wrist flexion, 40 degrees of metacarpophalangeal (MP) joint flexion, and a neutral position for the proximal interphalangeal (PIP) joints without dynamic traction. In addition, within the confines of the dorsal splint, the involved DIP joint was splinted at 40-45 degrees to prevent DIP joint extension during the early wound healing phases. Relaxed composite flexion was used to apply active tension to both the uninjured FDS, and the repaired FDP. This technique applies excursion of approximately 3 mm to the zone I tendon in a limited arc (45-75 degrees). The modified position of active flexion applies low loads of force (< 500 g), even with drag considered. This technique is supported by previous mathematical studies of excursion and internal tendon force, and clinical experience. Forty nine cases treated over a 10-year period were reviewed, and eight were excluded for incomplete follow-up. The use of this protocol for 41 zone I flexor digitorum profundus repairs by 12 different surgeons using varied surgical techniques was evaluated. None of the tendon to tendon repairs used more than two suture strands for the core repairs. Mean total active range of motion was 142 degrees (PIP 95 degrees plus DIP 47 degrees), or 81% of normal. Three tendons ruptured in non-protocol-related incidents and were excluded from the study. Results from this clinical study support the use of limited DIP extension combined with active tension with conventional repair in zone I.     

Kinematics of the proximal interphalangeal joint of the finger after surface replacement

Nine fresh-frozen normal human cadaveric long fingers were used to compare the kinematics of the proximal interphalangeal joint (PIP) before and after a resurfacing metal-polyethylene prosthetic replacement (Avanta prosthesis, San Diego, CA) using the magnetic Isotrak system (Polhemus Navigational Systems, Colchester, VT). The kinematics of the PIP joint after replacement were similar to that of the normal joint. The maximum angular displacement was 5 degrees for lateral deviation and 9 degrees for rotation during the passive flexion and extension motion. The center of rotation after implant insertion was nearly identical to the center of rotation of the normal joint. This anatomically designed PIP prosthesis has potential to restore normal motion to the finger PIP joint while resisting physiologic out-of-plane forces such as pinch and grasp.     

Surgical treatment of degenerative osteoarthritis of the fingers

Degenerative osteoarthritis of the long fingers is rare and surgical management is often necessary if there is joint pain, however this indication should not only be based on radiographic imaging. The specific anatomical problems of the metacarpophalangeal (MCP), proximal interphalangeal (PIP) and distal interphalangeal (DIP) joints are described. The surgical approach for each joint is described as well as functional management, in particular that of the extensor apparatus. Mobility should always be preserved for the MCP, arthroplasties are recommended for the PIP except for the index, and arthrodesis for the DIP. The different and most frequently used implants are described as well as the indications and expected results. The indications are discussed in relation to the limited results in the literature as well as the preferences of a panel of French hand surgeons.     

单枚克氏针固定并切开修复肌腱治疗锤状指畸形

目的 探讨应用单枚克氏针贯穿固定远、近侧指间关节治疗锤状指的临床疗效.方法 2005年2月-2007年8月,对18例锤状指行手术治疗.采用单枚1mm克氏针将远侧指间关节(DIP)固定于过伸位,同时贯穿固定近侧指间关节(PIP)于屈曲45°～60°位;修复伸肌腱,如伸肌腱止点处断裂或伴有撕脱骨折者,用微型骨锚或抽出式钢丝法固定.术后3周解除近侧指间关节固定,6周完全拔除克氏针.结果 术后随访2～6个月,远侧指间关节伸屈活动度为O°～70°11例,0°～600°4例,0.～55°2例,0°～35°1例.将患指与健指远侧指间关节的活动度相比较,参照TAM系统评定方法评定:本组优11例.良6例,差1例;优良率为94.4%.结论 应用单枚克氏针固定并切开修复肌腱.操作简单,固定牢靠,是治疗锤状指的有效方法.     

A biomechanical study of plate versus intramedullary devices for midshaft clavicle fixation

Background

Our understanding of finger functionality associated with the specific muscle is mostly based on the functional anatomy, and the exact motion effect associated with an individual muscle is still unknown. The purpose of this study was to examine phalangeal joints motion of the index finger generated by each extrinsic muscle.

Methods

Ten (6 female and 4 male) fresh-frozen cadaveric hands (age 55.2 ± 5.6 years) were minimally dissected to establish baseball sutures at the musculotendinous junctions of the index finger extrinsic muscles. Each tendon was loaded to 10% of its force potential and the motion generated at the metacarpophalangeal (MCP), proximal interphalangeal (PIP), and distal interphalangeal (DIP) joints was simultaneously recorded using a marker-based motion capture system.

Results

The flexor digitorum profundus (FDP) generated average flexion of 19.7, 41.8, and 29.4 degrees at the MCP, PIP, and DIP joints, respectively. The flexor digitorum superficialis (FDS) generated average flexion of 24.8 and 47.9 degrees at the MCP and PIP joints, respectively, and no motion at the DIP joints. The extensor digitorum communis (EDC) and extensor indicis proprius (EIP) generated average extension of 18.3, 15.2, 4.0 degrees and 15.4, 13.2, 3.7 degrees at the MCP, PIP and DIP joints, respectively. The FDP generated simultaneous motion at the PIP and DIP joints. However, the motion generated by the FDP and FDS, at the MCP joint lagged the motion generated at the PIP joint. The EDC and EIP generated simultaneous motion at the MCP and PIP joints.

Conclusion

The results of this study provide novel insights into the kinematic role of individual extrinsic muscles.     

Central slip tenotomy for the treatment of chronic mallet finger: an anatomic study

PURPOSE: Tenotomy of the central slip, described by Fowler, can clinically improve chronic distal interphalangeal joint (DIP) extensor lag secondary to mallet finger (terminal tendon disruption). The goal of this study is to evaluate the potential of central slip tenotomy to restore DIP joint extension. METHODS: A mallet deformity was reproduced in 15 fresh-frozen cadaver fingers after the extensor tendon insertion was sectioned over the DIP joint. A suture anchor inserted at the terminal insertion was then secured to the extensor tendon over the middle phalanx to reconstruct the extensor mechanism. A 500-g weight attached to the proximal extensor tendon applied extensor tension. Central slip tenotomy was then performed. DIP extensor lags before and after tenotomy were recorded. RESULTS: After sectioning of the terminal tendon over the DIP joint the average amount of extensor tendon lag produced was 45 degrees. After central slip tenotomy was performed the average amount of extensor lag correction was 36 degrees (range, 30 degrees-46 degrees). CONCLUSIONS: Several clinical studies have shown that central slip tenotomy is an effective treatment for chronic mallet finger but may not fully restore DIP joint extension. Our data suggest that patients with a pre-existing extensor lag of greater than 36 degrees may not achieve full extension from central slip tenotomy, although extensor lags of up to 46 degrees may be corrected.     

Surgical treatment for boutonniere deformity of the fingers. Retrospective study of 47 patients]

Disruption or laceration of the central slip of the extensor tendon at the proximal interphalangeal (PIP) joint with volar displacement of the lateral bands can result in the so-called boutonniere deformity which includes loss of extension at the PIP joint and compensatory hyperextension of the distal interphalangeal (DIP) joint. Many procedures has been described in the literature and no standard treatment can be recommended. The authors reports a series of 47 cases of posttraumatic boutonniere deformity. The mean follow-up was five years. Majority of patients were males (38 males). The mean age was 41 years-old (17-82 y.o.). The etiology was in 23 cases a missed subcutaneous disruption of the central slip of the extensor tendon and in 24 cases an inappropriate treatment of laceration of the extensor apparatus at the dorsal aspect of the PIP joint. The involved digit was in seven cases the index finger, in 14 cases the long finger, in 14 cases the ring finger and in 12 cases the little finger. It is essential to distinguish the supple boutonniere deformity without or after physical therapy (34 cases) and the stiff boutonniere deformity even after a hand physical therapy program (13 cases). Results were assessed on pain and active range of motion of the PIP joint as well as the range of motion of the DIP joint. Supple boutonniere deformities, except one treated by an isolated distal tenotomy of the extensor tendon (1/34), was treated by a procedure of reconstruction of the extensor apparatus including resection-suture of the central slip and redorsalisation of the lateral bands when there was a DIP hyperextension with a moderate flexion deformity of the PIP joint, and (33/34) with 90% of excellent and good results. Poor results (4/33) were due in two cases to the absence of physical therapy, in one case to septic osteoarthritis and in one to secondary rupture of the suture. For the 13 stiff boutonniere deformities, when the PIP flexion deformity was moderate, a distal tenotomy performed to correct the DIP hyperextension was satisfactory in three cases with a useful result (20 degrees-70 degrees). For destroyed PIP joint (osteoarthritis), two silicone spacers were implanted with also a satisfactory result (30 degrees-70 degrees). In the eight remaining cases, a teno-arthrolysis was performed combined with a reconstruction of the extensor apparatus as described. Six poor results were obtained with arthritic PIP joints (which should have required initially silicone implants), and two fair results (30 degrees-60 degrees) with non-destroyed PIP joints. Supple boutonniere deformity must always be treated by initial physical therapy. Surgical procedure with reconstruction of the extensor apparatus is satisfactory if the PIP joint is normal. When there is PIP osteoarthritis, it may be beneficial to perform a two-stage technique with tenoarthrolysis followed hand therapy and a secondary reconstruction of the extensor apparatus as these last procedure give satisfactory results on a supple boutonniere deformity.     

Two-stage grafting of digital flexor tendons: a review of 43 patients after 3 to 15 years.

We reviewed 9 (3-15) years postoperatively all 43 two-stage flexor tendon transplantations in fingers that had not otherwise been severely injured that we had operated on during the years 1984 to 1996. One digit had been reconstructed in each patient. The interval between the first and second stage operations was 19 (14-51) weeks. Time away from work was 44 (4-140) days after the first procedure and 101 (38-297) days after the second stage operation. After the second stage, 26 further procedures had been done in 18 of the 43 fingers. These included seven resutures of the transplanted tendon (three in the same finger), five tenolyses, two capsulotomies of the proximal interphalangeal (PIP) joint, three arthrodeses of the distal interphalangeal (DIP) joint (two combined with reinsertion of the tendon to the middle phalanx), one DIP + PIP arthrodeses, and three amputations of PIP. One further finger will be amputated and two patients do not wish treatment for ruptured transplants. There were 15 excellent, six good, nine fair, and 12 poor results at review. A total of 31 of the 43 patients said they would have had the operation if they had known the outcome in advance. Reconstruction of a flexor tendon takes a long time and causes many complications. Even so, it is indicated in motivated and fully informed patients because of a lack of other viable options.     

Simultaneous fracture-dislocations of the distal and proximal interphalangeal joints

Sixteen cases of simultaneous fracture-dislocations of both the distal interphalangeal (DIP) and proximal interphalangeal (PIP) joints in the same finger that were treated during the past 10 years were classified into three types: the swan-neck injury (dorsal fragment of the base of the distal phalanx at the DIP joint and palmar fragment of the base of the middle phalanx at the PIP joint); the double-hyperextension injury (palmar fragments at the DIP and PIP joints); and the straight-finger injury (with dorsal and palmar bone fragments at the DIP joint). The results of treatment were more satisfactory in PIP joints than in DIP joints.     

Immobilization of the mallet finger. Effects on the extensor tendon

Since the mallet finger that is treated with isolated splinting of the distal interphalangeal (DIP) joint can be moved freely proximal to the DIP joint, we sought to determine whether such motion might cause a tendon gap that could explain the extensor lag that often follows treatment. Experiments were performed on 32 cadaveric fingers with open mallet finger lesions, immobilizing either the DIP joint alone or both the DIP and PIP joints, while repeatedly flexing and extending the more proximal finger and wrist joints. For each experiment, the gap in the extensor tendon was measured. Joint motion proximal to the DIP joint and retraction of the intrinsics did not cause a tendon gap in a finger with a mallet lesion, supporting the convention that only the DIP joint needs to be immobilized.     

Surgical treatment of chronic mallet finger by shortening--suture of the tendon scar. Sixty six cases

Acute mallet fingers are commonly treated by splinting. Treatment of chronic injuries is more debated. Since 1989, a "shortening and suture" technique have been used for such chronic injuries on the elongated tendon scar. Sixty six of 77 patients treated on a 10 years period were reviewed with a mean follow-up of 21 months. The mean active extension lag at the distal interphalangeal (DIP) joint was 4.5 degrees (41 degrees of improvement) with 52% of fingers which recovered a full extension, representing 77% of good and excellent results according to Abouna's and Brown's modified criteria. There were two failures which lead to reoperation, and no complication (2 painful scars and 20% of cold intolerance). We propose this safe and simple technique for chronic mallet fingers if deformity exceeds 30 degrees, for patients untreated (after the second month), or when splinting has failed. "Swan-neck" deformities were improved by an associated Fowler procedure. In case of failure, a new "shortening and suture" or a DIP arthrodesis can be discussed.     

Total anterior tenoarthrolysis to treat inveterate flexion contraction of the fingers: a series of 16 patients

Total anterior tenoarthrolysis was originally described by Saffar to treat flexion contractions of the fingers. This procedure consists of releasing the entire flexor apparatus and the interphalangeal volar plates through a lateral incision and a volar subperiosteal dissection. The anterior flap slides proximally in relation to the bone, leaving a pulpar defect. To maintain the digital pulp intact, we proposed advancing the volar flap and transposing the defect at the base of the finger. A series of 16 patients who underwent total anterior tenoarthrolysis are presented; 6 patients underwent surgery according to our modification. Postoperative range of motion was improved in 11 of 16 patients and correlated with subjective patient appreciation. Fingers that had a preoperative interphalangel total active motion greater than 55 degrees were significantly improved. No improvement was seen among patients with stiff, crooked fingers. The average total extension deficit decreased from 33 degrees at the proximal interphalangeal joint level and 6 degrees at the distal interphalangeal joint level. Total anterior tenoarthrolysis is considered a salvage procedure to treat flexion contractures of the fingers with articular cartilages that are in good condition and tendons that are still working.     

Trigger finger treatment by ulnar superficialis slip resection (U.S.S.R.)

Surgical release of the A1 pulley for treatment of trigger finger normally produces excellent results. However, in patients with long-standing disease, there may be a persistent fixed flexion deformity of the proximal interphalangeal joint. This is sometimes due to a degenerative thickening of the flexor tendons and may be treated by resection of the ulnar slip of flexor digitorum superficialis tendon. One hundred seventy-two patients (228 fingers) who had undergone this procedure were reviewed at a mean follow-up of 66 months. Mean pre-operative fixed flexion deformity of the proximal interphalangeal joint was 33 degrees. All but eight fingers were improved by surgery and there was an average gain of 26 degrees in passive extension (7 degrees residual fixed flexion deformity) of the proximal interphalangeal joint. Full extension was attained in 141 of the 228 fingers, and in all 101 fingers with a pre-operative loss of passive extension of 30 degrees or less. This technique is indicated for patients with loss passive extension in the proximal interphalangeal joint and a long history of triggering.