Scaphoid proximal pole ejection in perilunate injury: a case report and pathophysiological hypothesis

Isolated ejection of the scaphoid proximal pole in perilunate injuries is rare, with only 4 reports in the literature, and does not correspond to the biomechanical situations in the Herzberg or Mayfield classifications. Bone ejection incurs a risk of avascular necrosis despite good osteosynthesis, notably because of precarious vascularization. We present a case of scaphoid proximal pole ejection and a theoretical hypothesis of the biomechanics of this injury. LEVEL OF EVIDENCE: 4.

Evaluation of the performance of three tenodesis techniques for the treatment of scapholunate instability: flexion-extension and radial-ulnar deviation

Chronic scapholunate ligament (SL) injuries are difficult to treat and can lead to wrist dysfunction. Whilst several tendon reconstruction techniques have been employed in the management of SL instability, SL gap reappearance after surgery has been reported. Using a finite element model and cadaveric study data, we investigated the performance of the Corella, scapholunate axis (SLAM) and modified Brunelli tenodesis (MBT) techniques. Scapholunate dorsal and volar gap and angle were obtained following virtual surgery undertaken using each of the three reconstruction methods with the wrist positioned in flexion, extension, ulnar deviation and radial deviation, in addition to the ulnar-deviated clenched fist and neutral positions. From the study, it was found that, following simulated scapholunate interosseous ligament rupture, the Corella technique was better able to restore the SL gap and angle close to the intact ligament for all wrist positions investigated, followed by SLAM and MBT. The results suggest that for the tendon reconstruction techniques, the use of multiple junction points between scaphoid and lunate may be of benefit.

Graphical abstract

Scaphotrapeziotrapezoid Joint Arthritis: A Pilot Study of Treatment with the Scaphoid Trapezium Pyrocarbon Implant

Isolated scaphotrapeziotrapezoid osteoarthritis is rare but can cause weakness and wrist pain. We present the results of a pilot study of interposition arthoplasty with a scaphoid trapezium pyrocarbon implant (STPI) by an open and arthroscopic approach for this problem. We performed this procedure in 10 hands in eight patients, all women, with a mean age of 60.5 (range 51–70) years. The average follow-up was 19 (range 2–24) months. Pre-operative X-rays in all cases identified an isolated degenerative arthritis of the scaphotrapeziotrapezoid joint. Average DASH evaluation pre-operatively of 49 was reduced to 39. All of the patients had functional improvement and returned to daily activities after 3 months. The results of this pilot study suggest that the STPI may prove a useful compromise treatment for this problem.

[Acutrak headless compression screw fixation for the treatment of scaphoid non-union]

OBJECTIVE

To evaluate the early clinical and radiographic outcome of scaphoid non-unions treated with Acutrak headless compression screw.

METHODS

From January 2008 to July 2011,21 patients with scaphoid non-union were treated in our department. There were 18 males and 3 females with a mean age of (23.6 +/- 4.6) years; 12 cases were on right hand and 9 were on left. According to Herbert-Fisher classification, there were 10 cases with type D1, 7 cases with type D2, 3 cases with type D3, and 1 case with type D4. The mean time from injury to operation was (12.4 +/- 2.7) months. All patients were treated with Acutrak headless compression screw fixation (6 cases received 2 screws fixation, 15 cases received 1 screw fixation, and Matti-Russe bone grafting was applied in 7 cases). The carpal height, the scaphoid index and changes of the scapholunate angle were assessed before and after the operation. Range of motion and grip strength were recorded and the wrist function was assessed according to the Patient-Rated Wrist Evaluation (PRWE).

RESULTS

Average duration of follow-up was (21.3 +/- 3.6) months. All the patients attained radiological union in a mean time of (13.3 +/- 2.4) weeks following the operation. No obvious complications were recorded. The surgical treatment allowed the preoperative mean scaphoid index of 0.61 +/- 0.13 and the preoperative mean scapholunate angle of (59.4 +/- 6.8) degree to be improved to 0.69 +/- 0.10 and (44.3 +/- 8.2)degree postoperatively, respectively. There was a substantial improvement in grip strength and pain amelioration after surgery. The preoperative mean PRWE score of 45.2 +/- 4.7 was improved to 76.1 +/- 5.2 postoperatively. All patients returned back to the original work,the average time from surgery to work was (6.0 +/- 1.1) months.

CONCLUSION

For scaphoid non-unions, Acutrak headless compression screw fixation can provide anatomical reduction, provide satisfactory results with a high union rate, well return of function and minimal complications in the early stage.

[Percutaneous fixation for the treatment of un-displaced scaphoid fractures with herbert cannulated screws through volar approach]

OBJECTIVE

To summarize the experience of percutaneous fixation of scaphoid fractures with Herbert screws through volar approach, and provide a reliable and efficient treatment method for scaphoid fractures.

METHODS

From April 2008 to September 2012,15 patients with scaphoid fractures were treated by percutaneous fixation with Herbert cannulated screws through volar approach including 14 males and 1 female with an average age of 35 years ranging from 25 to 45 years old. Among them, 10 cases were on left side and 5 cases were on right side. Durations from injury to operation ranged from 3 to 10 days with an average of 5 days. All these cases were identified as B2 type according to the Herbert classification based on X-ray and CT scan. In order to assess the function of wrist, all patients were calculated according to Krimmer's score postoperatively.

RESULTS

The follow-up period were from 5 to 18 months with an average of 10 months. At 3 months after operation,X-ray was re-checked every month. All the patients achieved bone union with a mean time of 10 weeks (ranged from 7 to 14 weeks) postoperatively. According to Krimmer's score, 14 cases gained 100 scores as perfect and one case got 90 scores as good. The small volar incision of all patients were union at the first period. No operation complications such as infection and nonunion occurred.

CONCLUSION

Percutaneous fixation with Herbert cannulated screws through volar approach is a reliable and efficient treatment method for scaphoid fractures with small invasion, high bone union rate, and fewer complications.

Ligamentous hyperlaxity and dorsal wrist ganglions

PURPOSE

To determine whether symptomatic dorsal wrist ganglions are associated with generalized ligamentous hyperlaxity.

METHODS

Ninety-six patients (61 females) presenting to hand surgeons for a symptomatic dorsal wrist ganglions were prospectively enrolled in this case-control investigation. Beighton scores were calculated to quantify generalized ligamentous laxity in each patient, and a scaphoid shift test (scapholunate capsuloligamentous laxity evaluation) was performed. A positive scaphoid shift test was defined by both pain and a palpable clunk. Ninety-six individuals without ganglions were then enrolled to form an age and sex frequency-matched control cohort. The control group was similarly assessed for Beighton score and scaphoid shift test. Binary logistical regression was performed to assess the association of ganglions with generalized ligamentous hyperlaxity (Beighton score ≥ 4) while accounting for effects of age and sex.

RESULTS

Patients with symptomatic dorsal wrist ganglions demonstrated significantly increased rates of generalized ligamentous hyperlaxity. Among those with ganglions, 27 of 96 (28%) patients exhibited generalized ligamentous hyperlaxity, compared with 12 of the 96 (13%) age- and sex-matched individuals in the control group. Patients with symptomatic dorsal wrist ganglions were also significantly more likely to demonstrate localized scapholunate hyperlaxity with a positive scaphoid shift test (25% positive scaphoid shift test with ganglions vs 1% in controls). In logistical modeling, patients with dorsal wrist ganglions had 2.9 (95% confidence interval [CI] 1.3-6.2) times greater odds of generalized ligamentous hyperlaxity compared with patients without a dorsal wrist ganglion after accounting for patient age and sex.

CONCLUSIONS

Symptomatic dorsal wrist ganglions were associated with both generalized ligamentous hyperlaxity and a positive scaphoid shift test. Although an association between wrist ganglions and ligamentous hyperlaxity does not prove causation, the possibility of the same underlying pathological entity causing both can be envisioned (ie, abnormal formation or organization of dense regular connective tissue).

TYPE OF STUDY/LEVEL OF EVIDENCE

Prognostic III.

Bilateral scaphotrapezium-trapezoid coalition with bipartite scaphoid: case report

We report on a 15-year-old girl with bilateral scaphotrapezium-trapezoid coalitions and bipartite scaphoids. There was no history of trauma or any other associated pathology. Wrist pain was alleviated by arthrodesis of the pseudarthrosis of the scaphoid component of the coalitions. Coalition of the distal portions of the scaphoids may have interfered with union of 2 ossification centers of the scaphoid. It is also possible that the carpal coalitions predisposed the scaphoid to fracture and that this represents bilateral nonunion.

The management of scapholunate wrist instability: a review

An injury to the ligament linking the scaphoid with the lunate is the most common and and budrened with the most negative sequelae cause of the carpal instability. It occurs most frequently as an associated injury at fractures of the distal radius. A review of methods of treatment of the pathology is provided, according to clinical advancement, duration form original trauma and condition of articular structures. Technical complexity of methods is directly related to severity of intrarticular changes. In early, dynamic instabilities, a simple, temporary scapholunate arthrodesis with K-wires is is an useful procedure, preventing further development of chronic instsbility. In later stages. The treatment is technically more demanding, considering re-alignment of carpal anatomy with ligaments or tendons (capsulodesis or tenodesis). An usefulness of arthroscopy in diagnostics and management at any stage of this pathology was emphasized.

Scaphoid excision and midcarpal arthrodesis: the effect of triquetral excision--a biomechanical study

PURPOSE

To evaluate the biomechanical alterations that occur after traditional scaphoid excision and midcarpal arthrodesis with and without excision of the triquetrum. The hypothesis of this study was that removal of the triquetrum increases the radiolunate contact pressure.

METHODS

We cyclically moved 10 fresh cadaver wrists using a wrist joint motion simulator while measuring the contact pressures between the proximal carpal row and the distal radius and ulna using a dynamic pressure sensor. We acquired data in the intact wrist, after a midcarpal arthrodesis with the scaphoid excised, and then again with the triquetrum removed, which is also known as a capitolunate arthrodesis.

RESULTS

The peak pressures in the radiolunate fossa significantly increased with either of the midcarpal arthrodeses compared with the intact wrist during each of the 3 dynamic wrist motions. In comparing the 2 midcarpal arthrodeses, the peak pressure in the ulnocarpal fossa significantly decreased after the triquetrum was removed during wrist radioulnar deviation and in the static ulnarly deviated position. After arthrodesis, we could identify no differences during any motion or static wrist position in the peak radiolunate pressures with or without the triquetrum.

CONCLUSIONS

We found that scaphoid excision and 4-corner arthrodesis shifts loads to the radiolunate joint. Isolated capitolunate arthrodesis with excision of the scaphoid and triquetrum further alters carpal kinematics and loading patterns.

CLINICAL RELEVANCE

These findings raise concern about routine excision of the triquetrum when performing a midcarpal arthrodesis.

[Importance of early diagnosis and operative treatment for trans-scaphoid perilunate dislocation]

OBJECTIVE

To evaluate the effectiveness of open reduction and internal fixation and repair of palmar ligment in treating trans-scaphoid perilunate dislocation.

METHODS

From June 1995 to June 2001,14 patients with trans-scaphoid perilunate dislocation were treated with open reduction and internal fixation and repair of palmar ligment. Among them,there were 13 males and 1 female,the ranging in age from 21 to 38 years,averaged 25.4 years. All patients were posterior dislocation and all operations were performed within 2 weeks after injury.

RESULTS

All patients were followed up from 24 to 60 months with an average of 28.3 months. Thirteen scaphoid fractures were primary healed and functions of wrist joint were good. Bone disunion was found in 1 case and part functions of wrist joint were limited. No found necrosis of lunate and scaphoid. According to clinical scoring system of Cooney, 9 case got excellent results, 3 good, 1 fair and 1 poor.

CONCLUSION

Open reduction and internal fixation and repair of palmar ligament is effective in treating trans-scaphoid perilunate dislocation,which can early provide steady fixation for scaphoid,and profit to recover blood supply of lunatum and subterminal scaphoid.

Scapholunate dissociation with radiolunate arthritis without radioscaphoid arthritis

PURPOSE

Watson and Ballet introduced the concept of a direct association between scapholunate (SL) dissociation and radioscaphoid (RS) arthritis with preservation of the radiolunate (RL) articulation in 1984. This principle has served as the anatomic, biomechanical, and pathophysiological basis for reconstructive surgery in the carpus. Recently, we have noted cases of concurrent SL dissociation and RL arthritis without RS arthritis, which is contrary to the accepted concept of wrist arthritis due to SL advanced collapse. The purpose of this study was to determine whether Watson and Ballet's thesis that SL dissociation results in RS joint degeneration with sparing of the RL joint can be confirmed, or whether another joint degeneration pattern can be associated with SL dissociation.

METHODS

The 3 authors independently reviewed 897 radiographs of the wrist in 691 male patients (206 bilateral and 485 unilateral) with diagnosis codes of wrist osteoarthritis (715.13), wrist instability (718.83), and wrist sprain (842.00). Posterior-anterior, oblique, and lateral views were available for all wrists. Elements assessed were RS joint, RL joint, SL joint, midcarpal joint, ulnar variance, ulnolunate joint, SL angle, and lunocapitate angle.

RESULTS

There were 146 wrists with radiographic SL dissociation. Nine wrists in 6 patients had radiographic SL dissociation and RL arthritis but no RS arthritis. An additional 6 wrists in 6 patients had radiographic RL arthritis but no SL dissociation or RS arthritis; however, 5 of these did have an SL angle of 60 degrees or greater.

CONCLUSIONS

Our results show that RL arthritis can occur in association with SL dissociation, and that the generally held view that the RL articulation is spared in SL advance collapse is not universally true. Consequently, it is our recommendation that both the RL and RS joints should be carefully evaluated for degenerative changes when planning treatment for patients with SL dissociation, because it should not be assumed that the RL joint has been spared.

Comparison of the "contact biomechanics" of the intact and proximal row carpectomy wrist

PURPOSE

The proximal row carpectomy (PRC) is a clinically useful motion-preserving procedure for various arthritides of the wrist. However, there are few studies on the "contact biomechanics" after PRC. The purpose of this study is to evaluate the contact biomechanics in terms of pressure, area, and contact location of the intact and PRC wrist.

METHODS

Six fresh-frozen cadaver forearms were tested in neutral, 45 degrees of flexion, and 45 degrees of extension. In the intact wrist, Fuji UltraSuperLow pressure contact film was placed in the radioulnocarpal joint. The specimen was loaded to a total force of 200 N. We then performed a PRC, and the experiment was repeated using Fuji Low film. The film was scanned and analyzed with a customized MATLAB program. Multivariable analysis of variance with multiple contrast testing and Student's t-test were performed for statistics.

RESULTS

In the intact wrist, scaphoid contact pressure averaged 1.4 megapascals (MPa), and lunate contact pressure averaged 1.3 MPa. In terms of contact location, scaphoid contact in the intact wrist significantly moved dorsal and ulnar in flexion and significantly moved volar and radial in extension. Lunate contact significantly moved dorsal in flexion. PRC wrist contact pressure was 3.8 times that of the intact wrist, and the contact area was approximately 26% that of the intact wrist. Lastly, in terms of the amount of contact translation after PRC, the capitate contact translated (7.5 mm) more than did the scaphoid contact (5.6 mm) and had about equal translation to that of the lunate (7.3 mm).

CONCLUSIONS

Contact pressure increased significantly and contact area decreased significantly after PRC. There is significant contact translation after PRC (more than scaphoid translation but equal to lunate translation), which provides quantitative support of the theory that translational motion of the PRC may explain its good clinical outcomes.

Temporary scaphotrapezoidal joint fixation for adolescent Kienböck's disease

PURPOSE

There are few therapeutic guidelines for adolescent Kienböck's disease. The purpose of our study was to investigate the clinical and radiographic outcomes of temporary scaphotrapezoidal (ST) joint fixation for adolescent Kienböck's disease.

METHODS

This was a retrospective review of 6 adolescent patients with Kienböck's disease treated by temporary ST joint fixation. All patients had pain with rest and activity before surgery. The mean patient age at the time of surgery was 14 years, and final follow-up examination was at a mean of 23 months. Under general anesthesia, 2 or 3 K-wires were inserted from the dorsal trapezoid to the scaphoid. The wires were removed at 3 to 6 months.

RESULTS

Mean postoperative wrist extension and flexion were increased from 46 degrees and 48 degrees to 68 degrees and 77 degrees , respectively. These improvements were statistically significant compared with preoperative wrist extension and flexion. Grip strength significantly increased from 52% to 86% of the unaffected side. None of the 6 patients had postoperative pain either at rest or with activity. On final follow-up wrist x-ray films, none of the patients had sclerotic change or fragmentation of the lunate, although decreased lunate height remained in all patients. Magnetic resonance imaging revealed improvement to nearly normal intensity of the lunate on T1- and T2-weighted images in all patients.

CONCLUSIONS

Both clinical and radiographic outcomes of temporary ST joint fixation for adolescent Kienböck's disease were excellent. We therefore recommend this procedure for the surgical treatment of adolescent Kienböck's disease.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic IV.

Spider plate fixation: no significant improvement in limited wrist arthrodesis

Using the Spider plate fixation device, limited wrist arthrodesis was performed on 30 patients over a 2-year period. Developed as an alternative to Kirschner wires and compression bone screws in limited intercarpal fusions, its rigid fixation was expected to yield better results. Five hand surgeons treated 24 men and 6 women with an average age of 45 years. Diagnosis included the following: scaphoid nonunion advanced collapse, scapholunate advanced collapse, scapholunate dissociation, midcarpal arthrosis, and Kienböck disease. The 8-hole regular Spider and 6-hole mini-Spider plates were applied dorsally, and patients were immobilized for 4 weeks. In a blinded study, data results showed no significant improvement when compared with bone screws and Kirschner wires. Preliminary results showed that the Spider plate yielded higher nonunion rates and less wrist motion.

Long-term follow-up of an undiagnosed trans-scaphoid perilunate dislocation demonstrating articular remodeling and functional adaptation

The most common perilunate dislocation is the trans-scaphoid dorsal perilunate variant. It is estimated that up to 25% of perilunate injuries are diagnosed late. We report 66-year follow-up of an unreduced, previously undiagnosed trans-scaphoid perilunate dislocation of the wrist. At follow-up, unique post-traumatic articular remodeling was seen on wrist radiographs, and the patient had only a mild functional deficit.

Association between lunate morphology and carpal collapse patterns in scaphoid nonunions

PURPOSE

Type I lunates have a single distal facet for articulation with the capitate; type II lunates have an additional (medial) hamate facet on the distal articular surface. We retrospectively reviewed a series of patients with scaphoid nonunions to determine if there was an association between lunate morphology and the degree of carpal instability observed. Association between lunate morphology and the location of the scaphoid fracture (proximal or waist) was also investigated.

METHODS

Radiographs were evaluated for 45 patients with established scaphoid nonunions. Lunate morphology, scaphoid fracture location, and radiolunate angle were determined.

RESULTS

Type I lunates were present in 21 patients. Of these, 15 were found to have a dorsal intercalated segment instability pattern (radiolunate angle greater than 15 degrees ). By contrast, only 4 of the patients with type II lunates exhibited this pattern of instability. No significant association was found between lunate morphology and the scaphoid fracture location.

CONCLUSIONS

Type II lunate morphology is associated with significantly decreased incidence of dorsal intercalated segment instability (DISI) deformity in cases of established scaphoid nonunion (p = .0002). Lunate morphology, however, was not significantly associated with the location of the scaphoid fracture in these cases (p = .19).

The influence of wire positioning upon the initial stability of scaphoid fractures fixed using Kirschner wires

A finite element model of the carpal scaphoid and its joints was developed to study how wire positioning affects the initial stability of the fixation of scaphoid waist fractures using Kirschner wires. A transverse fracture of the scaphoid waist was simulated along with its fixation using five different two-wire configurations. The resulting models were subjected to a load simulating a 200N force passing through the wrist. Friction between bony fragments was taken into account; as the friction coefficient of cancellous bone is unknown, three different values were analysed. For each of these friction coefficient values, the smallest transverse interfragmentary displacements, and consequently maximum initial stability, were obtained for the model that simulated the maximum gap between wires in the plane of fracture. Results also show that for a similar gap in the plane of fracture, more stable fixation can be achieved when wires cross each other not only in the frontal plane of the hand, but also perpendicularly to it.

The clinical implications of scaphotrapezium-trapezoidal arthritis with associated carpal instability

PURPOSE

Common causes of dorsal intercalated segment instability (DISI) include scapholunate dissociations and scaphoid fracture nonunions. Although less common than these, scaphotrapezium-trapezoidal (STT) osteoarthritis (OA) may also be associated with the development of a DISI deformity. The clinical implications of this form of carpal instability in cases of STT arthritis are still unknown. To study the radiographic progression and incidence of this entity, we reviewed our patients and report on 24 wrists with DISI in the presence of STT arthritis.

METHODS

A retrospective chart and radiographic review was performed on all patients seen between 1994 and 2004, with the diagnosis of STT arthritis to identify a subgroup of patients with DISI deformity on the presenting radiographs. Patients' clinical and surgical courses were noted. Postoperative radiographic changes were recorded, as were clinical outcomes.

RESULTS

Sixteen patients with 24 wrists having STT arthritis and DISI deformity on presenting radiographs were identified. The median STT arthritis grade was 3.0 based on a modified Eaton and Glickel grading system. The median radiolunate angle was -21 degrees of dorsal tilt. All patients had normal scapholunate angles. Abnormal scaphoid extension was seen in 19 of 24 wrists as measured by the radioscaphoid angle. Concomitant carpometacarpal arthritis was seen in 67% (n = 16) of the wrists, and midcarpal arthritis was identified in 50% (n = 8) of patients. Fifteen wrists required surgery for the symptoms and were followed up for a mean of 29 months after surgery. In the surgical group the radiolunate angles increased by mean of 6 degrees after surgery. Four of the 15 wrists required revisional surgery for persistent pain.

CONCLUSIONS

Patients with STT arthritis may present with carpal instability that is not related to radiographic scapholunate instability. This instability is characterized by a normal scapholunate angle with an extension stance of the scaphoid and lunate. Midcarpal arthritis may be present. Surgical intervention for patients with STT arthritis and DISI deformity may lead to radiographic progression of midcarpal instability.

Severity of scapholunate instability is related to joint anatomy and congruency

PURPOSE

To determine whether the bony architecture of the distal radius and proximal scaphoid have a role in stabilizing the scaphoid, and to determine whether a relationship between the bony geometry measurements and the amount of wrist constraint could be determined.

METHODS

Eight cadaver wrists were tested in a wrist joint motion simulator. The level of scapholunate instability after sectioning the scapholunate interosseous, radioscaphocapitate, and the scaphotrapezium ligaments was determined and related to radiographic measurements of volar tilt, lateral tilt (ulnar tilt of the radioscaphoid fossa), the depth of the radioscaphoid fossa, and 6 radii of curvature measurements of the proximal scaphoid and distal radius. The force to dorsally dislocate the scaphoid out of the radioscaphoid fossa was computed.

RESULTS

The radioscaphoid fossa and scaphoid curvatures were larger in those wrists that did not show gross instability after ligamentous sectioning in the wrist simulator. Similarly, those wrists with a deeper radioscaphoid fossa and greater volar tilt were also more stable. The force required to dislocate these wrists was greater than in those wrists that showed gross carpal instability.

CONCLUSIONS

This study suggests that the bony anatomy of the radius and scaphoid have a role in stabilizing the carpus after ligament injury. The effect of ligament sectioning on producing carpal instability may be moderated by the bone geometry of the radiocarpal joint. This may explain why some people may have a tear of the scapholunate interosseous ligament but not present with clinical symptoms.

Scaphoid Fracture Detection in a Military Population: A Standardized Approach for Medical Referral

OBJECTIVE

The objective was to test, refine, and implement an algorithm for early detection and referral of clinical scaphoid fractures by U.S. Army medical personnel. Our goal was to reduce complications resulting from delayed diagnosis and to improve outcomes affecting soldier health and unit readiness.

METHODS

Data on scaphoid fractures treated in the orthopedic department at Tripler Army Medical Center were collected from January 1, 2001, through December 31, 2003. Demographic variables included gender, age, and military rank.

RESULTS

The incidence of scaphoid fractures in our population was 43 cases per 100,000 personnel per year. An algorithm to guide nonorthopedic providers was developed after review of the medical literature.

CONCLUSION

We present an algorithm-based approach to soldiers presenting with post-traumatic wrist pain. The algorithm was fashioned with the aim of reducing complications and poor outcomes associated with delayed diagnosis of scaphoid fractures, affecting soldier health and unit readiness. A prospective study of the algorithm is underway.

Unusual combined scaphoid and lunate fracture of the wrist: a case report

All perilunate fracture-dislocations combine ligament ruptures, bone avulsions, and fractures in a variety of clinical forms. The most frequent is the dorsal trans-scaphoid perilunate dislocation. In rare cases, however, these dislocations also have been associated with capitate fractures, triquetral fractures, or lunate fracture. We report a combined scaphoid and lunate fracture of the wrist that was not associated with perilunate dislocation.

Screw fixation of scaphoid fractures: a biomechanical assessment of screw length and screw augmentation

PURPOSE

To assess the biomechanical stability relative to screw length and K-wire augmentation in scaphoid fracture fixation using a flexibility testing protocol and cadaver scaphoids whose soft tissue attachments remained undisturbed. Our hypothesis was 2-fold: increasing screw length and augmenting fixation with a K-wire would improve fracture fragment stability, individually and in combination.

METHODS

Flexion and extension loading applied through wrist tendons was performed on 10 cadaveric wrists after volar wedge scaphoid osteotomy and internal fixation. Each wrist participated in 3 experimental groups: short screw, long screw, and long screw augmented with a K-wire transfixing the distal pole to the capitate. Interfragmentary displacements were measured.

RESULTS

Analysis of variance showed significantly less fracture fragment motion with longer screws than with short screws in 4 of the 6 displacement axes. The flexion/extension axis rotations for the short, long, and augmented long-screw groups were 8.2 degrees +/- 4.8 degrees, 3.9 degrees +/- 1.6 degrees, and 1.8 degrees +/- 1.3 degrees, respectively. Although K-wire augmentation reduced displacement of the fracture fragments it did not decrease interfragmentary motion significantly when compared with the long-screw group.

CONCLUSIONS

Under physiologically applied loading of cadaveric wrists with unstable scaphoid waist fractures the long screw provided significantly greater stability than the short screw. Although K-wire augmentation in the long-screw group did improve stability the improvements were not significant. Based in part on the biomechanical data from this study it is our recommendation that the optimally placed screw for scaphoid fracture fixation stability is a long screw positioned down the central axis of the scaphoid deep into subchondral bone.

Vascularized bone grafts from the palmar radius for the treatment of waist nonunions of the scaphoid

PURPOSE

With their intrinsic vascularity vascularized bone grafts provide an alternative solution to the challenging problem of scaphoid nonunions. The union rate (after imaging evaluation including magnetic resonance imaging [MRI]) and functional outcome of using vascularized bone grafts pedicled on the palmar carpal epiphyseal artery for waist nonunions of the scaphoid are reported in this prospective case series.

METHODS

The technique was applied to 9 waist nonunions resulting from fractures. The mean time elapsed from the initial injury to the procedure was 22 months and the mean follow-up time was 24 months. The graft was pedicled on the artery running at the distal edge of the pronator quadratus and was inserted in the nonunion as an intercalary graft. Six patients had postoperative MRIs to evaluate fracture healing and graft incorporation.

RESULTS

Union was accomplished in all cases between 6 and 12 weeks. Postoperative MRI showed the viability of the graft (contrast-enhanced images) and confirmed union and graft incorporation. Complete absence of pain was noted in all patients. The Mayo modified wrist score increased from 63 to 92 after surgery and according to this score results were excellent in 5 patients and good in 4.

CONCLUSIONS

Vascularized bone grafts from the anterior radius lead to rapid union and consolidation in cases of waist nonunion. Postoperative MRI confirms viability of the graft, union, and graft incorporation. The approach is limited to the distal radius and wrist and lacks donor site morbidity. The interposition of the graft from the palmar side allows correction of the humpback deformity and patients regain carpal height, grip strength, and painless motion.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic, Level IV.

Arthroscopic debridement and closed pinning for chronic dynamic scapholunate instability

PURPOSE

For chronic dynamic scapholunate (SL) instability (>3 months after injury) open procedures (capsulodesis, limited intercarpal fusions, tenodesis, SL ligament reconstruction) have become popular in recent years but their long-term results have been suboptimal. We evaluated retrospectively the results of aggressive arthroscopic debridement of the SL ligament to bleeding bone in an effort to induce scar formation and closed pinning of the SL joint in patients unwilling to have an open procedure.

METHODS

Eleven patients (mean age, 37 y) presenting with persistent posttraumatic pain and weakness to the wrist were diagnosed with dynamic SL instability (positive Watson scaphoid shift test result, SL gapping on grip-view radiographs, arthroscopic findings of a Geissler grade III or IV SL tear) and treated. Range of motion, grip strength, radiographic measurements, and the Mayo wrist score were used to evaluate the results.

RESULTS

The mean follow-up period was 33 months (range, 12-76 mo). Three patients had subsequent surgery 9 to 11 months after the procedure. Subsequent surgeries included a dorsal capsulodesis, a four-corner fusion, and a wrist arthrodesis. Of the 8 remaining patients there were 2 excellent, 4 good, 1 fair, and 1 poor result based on the Mayo wrist score. In these patients the mean range of motion was 65 degrees of extension to 59 degrees of flexion and the mean grip strength was 82% of the uninjured contralateral extremity. Although persistent radiographic SL gapping in grip views was noted in all 8 patients none progressed to static instability or dorsal intercalated segment instability.

CONCLUSIONS

The results of this technique are suboptimal; however, it may be an option for patients unwilling to have more than an arthroscopic procedure or those requiring maintenance of wrist motion, provided they understand the risks and benefits of this approach.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic, Level IV.

Dorsal capsulodesis for scapholunate instability--effect on patient disability and wrist pain

Twenty cases of scapho-lunate instability have been reviewed, to determine the effect of dorsal capsulodesis on disability and wrist pain. The average follow-up was 41 (range 13-63) months. There was a significant improvement in the pre-operative Patient Rated Wrist Evaluation score from 108 (range 18-150) to a postoperative score of 60 (range 0-132). All wrist movements and grip strength were reduced postoperatively but only the reductions in flexion and radial deviation were statistically significant. Seventeen (85%) patients were satisfied with the operation. One patient remained unemployed after surgery. Five patients returned to their normal jobs. This study shows that dorsal capsulodesis should remain an important option in the treatment of scapholunate instability.

[Dorsal capsulodesis versus triscaphe arthrodesis in patients with scapholunate dissociation. Do the results depend on the diagnosis or the operation?]

BACKGROUND

Dorsal capsulodesis and triscaphe arthrodesis are possible treatment modalities for patients with scapholunate dissociation. In light of overlapping indications for either operation for patients with carpal instability, it is important to compare the postoperative results.

METHODS

From 1998 until 2002, we operated on 87 patients suffering from scapholunate dissociation. 52 patients were treated by dorsal capsulodesis after R. Berger and 35 patients were treated by triscaphe arthrodesis as published by Watson. Of these 87 patients, we managed to follow-up 77 patients (47 dorsal capsulodesis und 30 triscaphe arthrodesis) with a physical examination, X-ray of the wrists and Krimmer Score.

RESULTS

In terms of grip-strength, range of motion, functional outcome (Krimmer Score), duration of the operation and hospitalisation, the dorsal capsulodesis group performed better (p < 0.05) than the triscaphe arthrodesis group at the time of follow-up. At follow-up, pain reduction was significant in both groups (p < 0.05). Krimmer Score (functional outcome) and the rate of complication was clearly better for the dorsal capsulodesis group as compared to the triscaphe arthrodesis group.

CONCLUSION

In case of non-static scapholunate dissociation, dorsal capsulodesis should be the first choice treatment. In case of a young manually working man with static scapholunate dissociation, it should be a case-to-case decision whether performing a triscaphe arthrodesis or a dorsal capsulodesis. With this investigation we wanted to discuss and demonstrate the difficulties with the differential-indication for the two operations. Generally speaking the postoperative results did not depend on the type of scapholunate dissociation (dynamic versus static) but rather on the chosen surgical procedure.

Fractures récentes du scaphoïde (moins de trois semaines)

Scaphoid fractures are the most common carpal fracture, accounting for 70 a 80% of all fractures of the wrist. The diagnosis of acute fracture of the scaphoid still continues to be missed despite an increasing improvement of imaging techniques. In fact, these fractures are mainly neglected because of minimal early symptoms or quick resolution of initial symptoms. X-ray analysis of acute fractures is rather difficult because of the irregular shape of the scaphoid and its overlapping with other structures. In case of doubtfull or negative initial radiographic views, a technetium 99 bone scan or MR imaging should be consisidered. These fractures occuring in the young and most active members of our society represents a population that doesn't have the patience for traditionnal immobilisation in cast. Thus patients with undisplaced fractures for whom early return to work or sport is a primary concern, percutaneous repair with cannulated screw fixation using fluoroscopy and even aided with arthroscopy represents an increasing option. Nevertheless, in thoses cases, cast immobilisation should always be first considered. If percutaneous internal fixation is the first choice in proximal pole fractures or fractures seen with a delay, in the other cases, it can only be advocated if internal fixation will provide a stable reduction. There is little controversy for the treatment of displaced unstable scaphoid fractures. Open repair and internal fixation with a screw represents the golden standard. Complex displaced or dislocated fractures are often comminuted and associated with bony defect. Accurate reduction may need to perform a bone graft. The ligamentous injuries should also be carefully repaired . Evidence of associated cartilagenous lesions must be asessed with precision, as they always jeopardize the end result.

Funktionelle Ergebnisse nach Entfernung der proximalen Handwurzelreihe bei SNAC- und SLAC-Wrist Stadium II

The proximal row carpectomy (PRC) is a motion preserving procedure which creates a new joint without arthrosis. It is a frequently used procedure in stage II of a posttraumatic degenerative arthrosis of the wrist after scaphoid nonunion or scapholunate ligament instability (SNAC-/SLAC-wrist). In this retrospective analysis the functional postoperative results of this operation are compared in light of a homogenous indication (SNAC-/SLAC-wrist stage II). In 38 patients PRC was performed for a stage II SNAC- (n = 29) or SLAC-wrist (n = 9) between June 1994 and March 2002. Postoperative examination included range of motion and grip strength. Pain was assessed using a visual analogue scale (VAS 0 - 100). The DASH questionnaire (disability of the arm, shoulder and hand) was used to evaluate the disabilities in activities of daily living (ADL). Thirty patients (79 %) with a mean age of 39 years (23 - 59) were evaluated with a mean follow-up of 27 months (6 - 100). Mean extension and flexion of the wrist reached 75 degree which was 57 % of the contralateral hand. Mean radial and ulnar deviation was 33 degree corresponding with 52 % of the contralateral hand. The average grip strength was 50 % of the unaffected side. The postoperative DASH score was 27.4. Pain with strenuous activity was reduced by 40 %, resting pain by 77 %. Three patients showed radiological signs of a radiocapitate arthrosis, one patient needed conversion into a complete wrist arthrodesis. Our results are in concordance with the literature. However, our follow-up time is relatively short and we cannot make any conclusion about the long-term outcome. PRC is a technically straightforward procedure for treatment of carpal collapse. For stage II of the SNAC-/SLAC-wrist we consider the resection of the proximal carpal row an alternative procedure to the midcarpal arthrodesis particularly in patients who require less grip strength and when a shorter postoperative immobilization is reasonable.

Ersetzt der Disability of Arm, Shoulder and Hand Questionnaire (DASH-Fragebogen) die Erfassung von Bewegungsausmaß und Kraft bei der Bewertung von Ergebnissen?

Scoring systems currently used to evaluate functional disabilities in upper extremity conditions frequently combine so-called "objective" parameters such as grip strength and range of motion with "subjective" parameters such as pain. Since its introduction, the Disabilities of Arm, Shoulder and Hand Questionnaire has proven useful in the pre- and postoperative evaluation of functional limitations of the upper extremity. This study examines the relationship between DASH scores, the so-called "objective" parameters of grip strength and range of motion and those of "mixed scores" such as Krimmer and Cooney Scores. Based on the data of six diagnostic groups, Spearman's correlation coefficients were calculated. There was no correlation between DASH scores and range of motion, however, some of the diagnostic groups showed a moderate correlation between DASH scores and grip strength. Both the Krimmer and Cooney scores showed a significant correlation with the DASH scores, indicating that these "mixed-scores" can be replaced by the DASH. Since it has been shown that grip strength and range of motion do not capture patients' functional limitations adequately, their continued use in the evaluation of upper extremity conditions should be the topic of further discussion.

Capsulodesis for the treatment of chronic scapholunate instability

PURPOSE

Scapholunate (SL) instability is the most common form of carpal instability. The treatment of this disorder is challenging and varying treatment options have been described. The purpose of this study was to examine the intermediate-term results of dorsal capsulodesis for cases of chronic SL dissociation.

METHODS

A retrospective analysis was conducted that examined all dorsal capsulodesis procedures performed for chronic SL dissociation between January of 1990 and February of 2000. Wrist pain had to be present for greater than 3 months. Patients had to have a minimum follow-up period of 2 years for inclusion in the study. Thirty-one patients were identified with isolated chronic SL dissociation. Of the 31 patients 18 had dynamic carpal instability and 13 had static carpal instability. The time from injury to surgery averaged 20 months. The follow-up period averaged 54 months (range, 24-96 mo). All patients had a dorsal capsulodesis procedure using either a Blatt or Mayo technique. Results were reviewed clinically and radiologically. Static and dynamic groups were compared with a Student t test.

RESULTS

There was a 20% decrease in wrist motion after capsulodesis. There was no improvement in grip strength after surgery. Most patients had improvement in pain but only 2 patients were completely pain free. Radiographically the SL gap increased over time from 2.7 mm before surgery to 3.9 mm at the final follow-up evaluation. The SL angle also increased from 56 degrees before surgery to 62 degrees on final follow-up evaluation. There was no statistical difference in overall wrist motion, grip strength, or wrist score between the dynamic and static groups. The time to surgery and age had no significant effect on overall outcome.

CONCLUSIONS

Dorsal capsulodesis provided pain relief for patients with both dynamic and static SL instability. Although pain was improved it was not completely resolved in the majority of cases. From a radiographic perspective dorsal capsulodesis did not provide maintenance of carpal alignment in cases of chronic SL dissociation.

Changes in radiocarpal loading characteristics after proximal row carpectomy

PURPOSE

To document the changes in wrist loading that occur after proximal row carpectomy in a cadaver model.

METHODS

The normal radioulnar carpal pressure distributions of 7 cadaver wrists were measured using super-low-pressure-sensitive film. Proximal row carpectomies were performed and the loading characteristics re-evaluated.

RESULTS

In the lunate fossa the contact area increased 37%, the average contact pressure increased 57%, and the location of the contact moved radially 5.5 mm. With wrist motion between 40 degrees of extension and 20 degrees of flexion the volar/dorsal excursion of the lunate fossa contact point increased by 108%.

CONCLUSIONS

Significant changes in radiocarpal loading occur after proximal row carpectomy. The increased radiocarpal excursion with wrist motion may explain the low incidence of radiocapitate arthritis in patients who have had proximal row carpectomy.

Basal joint arthroplasty and carpal tunnel release through a single incision: an in vitro study

PURPOSE

Carpal tunnel syndrome coexists with basal joint arthritis in a large percentage of patients. These 2 conditions are often treated surgically through separate incisions. The purpose of this cadaver study is to show the effect of trapeziectomy and transverse carpal ligament release from the scaphoid tubercle on carpal canal pressures. This technique may permit both problems to be addressed through the same Wagner incision.

METHODS

In 4 fresh frozen cadaver limbs pressures in the carpal canal were elevated to 30 mm Hg through a percutaneously placed balloon. Pressures were measured using an 18-gauge sideport needle via a transducer. Trapeziectomy and release of the transverse carpal ligament from the scaphoid were performed in succession through a Wagner incision with canal pressures measured after each step.

RESULTS

Carpal canal pressures decreased after trapeziectomy (mean, 7 mm Hg; range, 3-14 mm Hg) but did not return to baseline (0 mm Hg) until complete release of the ligament.

CONCLUSIONS

Decompression of the carpal tunnel can be performed effectively through a Wagner incision during basal joint arthroplasty. This cadaver model shows reduction in the canal pressures after trapeziectomy and release of the transverse carpal ligament. This single-incision approach is attractive because it may decrease morbidity compared with a 2-incision approach in patients with concomitant carpal tunnel syndrome and basal joint arthritis.

Correction dynamique d’une instabilité statique scapholunaire par transfert tendineux actif du muscle court extenseur du carpe : rapport préliminaire

We present the case of a twenty year old man who developed static scapholunate instability on the right side following a road traffic accident seven months previously. A dynamic surgical technique was devised to treat this problem using the tendon of extensor brevi carpi radialis as an active transfer. The tendon, divided at its insertion on the base of the third metacarpal, was reinserted into the distal part of the scaphoid using two anchors after shortening it by removing the distal centimetre. The tendon was rerouted via a pulley created 'de novo' at Lister's tubercle in order to centre the tendon on the same axis as the scaphoid. No other material was used for bone fixation. The wrist was immobilized in extension for six weeks. The clinical and radiological result eight months after the intervention showed excellent reduction of the scapholunate joint and a pain-free wrist with satisfactory mobility.

Treatment of scapholunate dissociation: ligamentous repair associated with modified dorsal capsulodesis

We previously reported that our repair and/or reconstruction of the scapholunate interosseous ligament reduced the scapholunate dissociation and improved the clinical results. Re-evaluation of these patients after three years revealed that malrotation of the scaphoid advanced significantly although the clinical results declined only slightly. To prevent progression of scaphoid malrotation, a modified dorsal capsulodesis was subsequently added to the ligamentous repair of scapholunate dissociation. The records of 17 patients were available for this study. The time lapse from injury to surgical treatment ranged from four days to one year and six months. All but three patients were operated less than two months after the injury. All patients were followed for more than one year, with an average of 49 months. Clinical results were expressed by a modification of the point score method of Green and O'Brien. Scapholunate angles were measured on lateral X-ray films with the wrist in neutral position. Overall clinical results averaged 83 points (range: 25-100). The scapholunate angles averaged 49 degrees (range: 45-60). In the three patients, in whom the operation was performed more than 11 months after the injury, the clinical results averaged 38 points and scapholunate angles averaged 54 degrees, respectively. These clinical and X-ray results suggest that early repair of the scapholunate interosseous ligament along with a modified dorsal capsulodesis is a useful procedure in the treatment of scapholunate dissociation.

The effect of pronation and supination on the minimally displaced scaphoid fracture

The amount of rotation that occurs at the scaphoid waist fracture site with pronation and supination of the forearm is studied in 10 upper extremities from cadavers. Two colinear metal markers were placed in the osteotomized scaphoid and a below-the-elbow cast was applied. Spiral volumetric computed tomography scanning of the scaphoid was done with multiplanar reformation to evaluate displacement of the metal markers. Four of the 10 specimens also were studied without any immobilization. The total magnitude of motion from pronation to supination averaged 0.2 mm in the specimens with a below-the-elbow thumb spica cast, and 2.4 mm in specimens without immobilization. The current study showed no significant rotation at the minimally displaced scaphoid waist fracture site during pronation and supination in a below-the-elbow cast. Furthermore, there is unacceptable rotation at the fracture site in the absence of a cast. Based on this study, a below-the-elbow thumb spica cast seems adequate for fracture immobilization; however, clinical correlation is needed.

Scaphoid kinematic behavior after division of the transverse carpal ligament

PURPOSE

The effect that carpal tunnel release (CTR) has on scaphoid motion has not been reported. Accordingly the purpose of this study was to determine the flexion/extension behavior of the scaphoid during global wrist radial/ulnar deviation before and after division of the transverse carpal ligament (TCL).

METHOD

In this study we examined the in vitro kinematics of the scaphoid during wrist deviation in 6 cadaver forearms both before and after the division of the TCL using a computerized camera monitoring system. The specimens were evaluated in 13 different positions, from 20 degrees of radial deviation to 40 degrees of ulnar deviation at increments of 5 degrees.

RESULTS

The data indicate that the difference in scaphoid position after TCL division is statistically significant when the wrist is in ulnar deviation of 15 degrees or greater. In addition a significant difference in scaphoid extension between pre- and post-TCL division conditions was found at 5 degrees of radial deviation as well as at 5 degrees or more of ulnar deviation and increased with increasing ulnar deviation.

CONCLUSIONS

Scaphoid kinematics are altered considerably in radial-ulnar deviation after division of the TCL. This alteration may have long-term consequences and contribute to commonly seen post-CTR symptoms.

Central placement of the screw in simulated fractures of the scaphoid waist: a biomechanical study

BACKGROUND

Recent reports on internal fixation of acute fractures of the scaphoid waist have demonstrated higher rates of central placement of the screw when cannulated screws were used than when noncannulated screws were used. This cadaveric study was designed to determine whether central placement in the proximal fragment of the scaphoid offers a biomechanical advantage.

METHODS

Eleven matched pairs of scaphoids were removed from fresh cadaveric wrists. Each scaphoid was placed in a custom manufactured jig that was used to create reproducible central and eccentric positioning of the guidewire. Then a linear osteotomy was made followed by placement of a Herbert-Whipple cannulated screw to fix the osteotomy. The specimen was then potted in a holder with use of polymethylmethacrylate with a Kirschner wire passed through the proximal end of the scaphoid and placed into a fixture with a pneumatically driven plunger resting on the surface of the distal pole. The load acting through the plunger was measured with use of a load-cell, and its excursion was measured with use of a linear variable differential transformer. Stiffness, load at 2 mm of displacement, load at failure, and mechanism of failure were measured, and the two groups were compared with regard to stiffness and strength.

RESULTS

Central placement of the screw in the proximal fragment of the scaphoid had superior results compared with those after eccentric positioning of the screw. Fixation with central placement of the screw demonstrated 43% greater stiffness (12.7 N per mm compared with 8.9 N per mm; p < 0.01), 113% greater load at 2 mm of displacement (126 N compared with 59.1 N; p < 0.01), and 39% greater load at failure (712 N compared with 513 N; p > 0.05).

CONCLUSIONS AND CLINICAL RELEVANCE

Central placement of the screw in the proximal fragment of the scaphoid offers a biomechanical advantage in the internal fixation of an osteotomy of the scaphoid waist. Clinical efforts and techniques that facilitate central placement of the screw in the fixation of fractures of the scaphoid waist should be encouraged.

The relationship between proximal pole blood flow and the subjective assessment of increased density of the proximal pole in acute scaphoid fractures

The cause and importance of increased density of the proximal pole of the scaphoid seen in radiographs after an acute fracture were investigated. Blood flow to the proximal poles of 32 nonsurgically treated scaphoid fractures were assessed 1 to 2 weeks after injury by measuring their uptake of gadopentetate dimeglumine with dynamic magnetic resonance imaging and calculating its steepest slope and percentage of enhancement values. Initial (week 0) and week 8 scaphoid series radiographs were independently assessed by 2 observers for increased proximal pole density; both agreed that the density had increased during treatment in 9 fractures. All 9 fractures united, suggesting that increased proximal pole density is not a major determinant of fracture outcome. Increased density of the proximal pole was associated with low proximal pole blood flow, but this relationship was not absolute, suggesting that other factors contribute to the appearance of increased density.

The effect of sectioning the dorsal radiocarpal ligament and insertion of a pressure sensor into the radiocarpal joint on scaphoid and lunate kinematics

The role of the dorsal radiocarpal wrist ligament has been the subject of several investigations. Several biomechanical studies have used sensors inserted dorsally into the wrist joint to evaluate its pressure distribution. The purpose of this study was to evaluate whether a dorsal capsulotomy that sections the dorsal radiocarpal ligament or insertion of a flexible pressure sensor alters scaphoid or lunate kinematics. Eight cadaver upper extremities were instrumented with motion sensors and placed in a wrist joint simulator. Each arm was moved through continual cycles of wrist flexion/extension and radial/ulnar deviation. Motion data were obtained in the intact state, after a capsulotomy, and after insertion of the sensor. We found that either a dorsal capsulotomy sectioning the dorsal radiocarpal ligament or insertion of the pressure sensor alters scaphoid and lunate kinematics during dynamic wrist motion. This study supports the clinical belief that this dorsal wrist ligament should be spared during surgical approaches to the carpus.

Scaphoid injuries in children

In order to establish an acceptable working protocol for the care of children with scaphoid injuries, an independent study was undertaken by the author. This paper describes the various aspects of this study: understanding what the scaphoid is and its function, the correct examination of the hand and wrist and the rationale behind it, the rationale behind the current treatment of suspected scaphoid injuries, and the development of the carpal bones and skeletal age. Opinions differ as to what age the scaphoid develops and therefore when it may be fractured, and so a review of research and literature on scaphoid injuries is also outlined.

Acutrak screw fixation versus cast immobilisation for undisplaced scaphoid waist fractures

Fifty-three patients with less than 14 day-old, undisplaced fractures of the waist of the scaphoid were randomized to two groups. Twenty-eight patients were treated by immobilisation in a below elbow plaster cast for 10 weeks while 25 were treated by percutaneous insertion of an Acutrak standard screw. There were no statistically significant differences between the two treatment groups with regard to either the rate of union or the time to union. Patients who underwent surgery had a significantly better range of motion at 16 weeks but there were no significant differences for grip strength. Acute percutaneous internal fixation of undisplaced scaphoid waist fractures using the Acutrak screw allows early mobilisation without adverse effects on fracture healing.

[A adaptive proximal scaphoid implant]

INTRODUCTION

In this study, the insertion of a pyrocarbon implant (APSI) has been described, which is shaped to allow adaptive mobility during carpal movement in the first row of carpals. This implant replaces the proximal part of the scaphoid; it is designed to treat styloscaphoid arthritis, and to prevent further deterioration and carpal collapse by restoring the first carpal row to its original height, i.e., 'SNAC wrist' after scaphoid pseudoarthritis, and 'SLAC wrist' following scapho-lunate dissociation.

MATERIALS AND METHOD

This retrospective series included 25 cases which were examined and analyzed at an average of six years post-surgery (between three and ten years) by an independent observer using the EVAL expert database system: 1) 14 cases involved pseudoarthritis, which developed from the scaphoid ('SNAC wrist'); 2) ten cases were connected with scapho-lunate nonunion ('SLAC wrist'); 3) one case involved carpal collapse with siliconite, which had previously been inserted as a scaphoid silicone partial implant for the treatment of pseudoarthritis involving a stage II fracture.

RESULT

In all cases, the reason for the preoperative-consultation for degenerative arthritis was the presence of pain, which post-surgery was no longer apparent in 60% of cases, and only persisted during effort in 28% of cases. Thus 88% of the patients were satisfied with the results, and were able to resume their normal professional and sports activities at the same level as before. Strength connected with digitopalmar grip and pinch force were found to have increased compared to the function in the healthy hand. No implant dislocation was detected by radiological investigation. Dynamic X-rays of the implant in flexion, extension, and frontal inclination confirmed this adaptive mobility. Carpal height was in all cases maintained. The radio-lunate angle remained unchanged in 15 cases, was improved in six cases, and was worse in four cases. Two poor results were connected with severe ligament lesions prior to surgery.

CONCLUSION

The preliminary results regarding the APSI implant seem to be promising for cases of polar pseudoarthritis in which curative treatment is no longer possible. This technique avoids further deterioration and carpal collapse ('SNAC wrist'). However, in cases of scapho-lunate nonunion ('SLAC wrist') where ligament lesions are severe, this method does not resolve the problem of ligament destabilization, which requires further treatment.

The scaphotrapezio-trapezoidal joint. Part 2: A kinematic study

Kinematics of the scaphotrapezio-trapezoidal joint during wrist flexion/extension motion (FEM) and radial/ulnar deviation (RUD) was investigated using a 3-dimensional dynamic motion analysis system. The scaphoid/trapezoid motion was found to be a rotational motion obliquely oriented relative to the sagittal plane of the wrist and described in an ulnoflexion/radial extension motion plane in both FEM and RUD of the wrist. The axis of rotation of the scaphoid/trapezoid motion during both FEM and RUD wrist motions was essentially the same and runs through the radiopalmar aspect of the distal scaphoid and the waist of the capitate. Motion analysis also revealed that the trapezium-trapezoid and trapezoid-capitate joints are essentially immobile. Hence, the scaphotrapezio-trapezoidal motion is considered to be a single degree of freedom that is essentially the same in both FEM and RUD of the wrist.

Rotary subluxation of the scaphoid. Revisited

The SL ligament complex and volar radiocarpal ligaments provide scaphoid stability both at the SL joint and, more importantly, at its distal radius articulation. With disruption or attenuation of these ligaments, rotational displacement of the scaphoid occurs about its longitudinal axis. This results in distal scaphoid flexion and proximal pole subluxation dorsally, toward the distal radius rim. Rotary subluxation of the scaphoid accurately describes this condition, and represents a spectrum of radioscaphoid instability based upon the severity and chronicity of ligamentous disruption. Diagnosis is based upon identification of specific clinical and radiographic features. Recognition of this entity provides for a more rational basis for treatment of ligamentous injuries of the wrist.