[Abstract] Objective To evaluate the clinical effect of early incisional reduction and Herbert screw internal fixation in the treatment of perilunate dislocation of the navicular bone. Methods: Eight cases of fresh periprosthetic dislocations were treated with early incision and Herbert screw internal fixation, and were followed up for 7-35 months, with an average of 14 months. The results of the Cooney wrist score were excellent in 3 cases, good in 2 cases, moderate in 2 cases, and poor in 1 case, with a mean score of 76. The DASH score was 27. The navicular bone healed completely on X-ray, and the wrist axis recovered well. Conclusion Early incisional reduction Herbert screw internal fixation can achieve anatomical repositioning of the navicular bone, restoration of the wrist joint axis, and better postoperative functional recovery, which is a better method for treating fresh perilunate dislocation via navicular bone.
【Key words】fracture; fracture fixation, internal; dislocation; navicular bone
From August 2004 to April 2007, we treated 8 cases of periprosthetic dislocation with early incisional repositioning and Herbert screw internal fixation. The results are reported as follows.
Data and methods
I. General information: All 8 cases in this group were male; the average age was 30 years (24-41 years). There was one case on the left side and seven cases on the right side, and the right side was the dominant hand in eight cases. The average time from injury to surgery was 7 days (3-15 days), and the time from injury to surgery was within 1 week in 3 cases, 1-2 weeks in 3 cases, and 2 cases in 2-3 weeks. 1 of the 8 cases had a combination of median nerve damage, 1 radial styloid fracture, 1 ulnar styloid fracture, and 1 pelvic fracture. The cause of injury was dorsal extension of the wrist joint in 7 cases and direct blow of heavy object in 1 case. The fracture of the navicular bone was fixed with Herbert screws, and iliac bone graft was performed in three cases.
After brachial plexus or general anesthesia took effect, an “s”-shaped incision was made along the dorsal side of the wrist in the direction of the thumb extensor tendon, and the third extensor tendon sheath was opened layer by layer, the thumb extensor tendon was tracted to the radial side, and the fourth extensor tendon sheath was opened through the third extensor tendon sheath. A “V”-shaped incision was made between the dorsal radial deltoid ligament and the intercarpal ligament according to the Bishop’s method to form a joint capsule flap with the radial aspect of the wrist joint as the tip. The dorsal carpal capsule is lifted to reveal the navicular, lunate and triangular bones. For the palmar approach, a 4M longitudinal incision is made along the radial side of the palmar carpal flexor tendon to the navicular tuberosity, which is then deviated 45º to the radial side to reveal the navicular tuberosity. The joint between the navicular bone and the greater trochanter was opened to reveal the ligament between the radial navicular bones, and the extent of injury was observed and closed directly with 4-0 absorbable suture.
Clear the blood accumulation in the joint, check the displacement of the navicular fracture and the damage of the intercalary ligament and lunotriquetral ligament, reset under direct vision, and drill a Kirschner needle parallel to the lunar bone from the cephalic bone to fix the position of the cephalic bone and the lunar bone, or drill another Kirschner needle percutaneously from the radius to the lunar bone to maintain the stability of the position between the radial and lunar bones. After the lunar and triangular bones are repositioned, two Kirschner pins are drilled parallel from the triangular bone toward the lunar bone through the skin to stabilize the position between the triangular bone and the lunar bone and prevent their separation; if the navicular lunar interosseous ligament is injured, the navicular bone is fixed with Kirschner pins and fused with 4-0 absorbable sutures.
If the navicular fracture is repositioned anatomically under direct vision, the iliac bone can be implanted in the case of comminuted navicular fracture, and a 0.8-1.0 mm diameter guide kerf pin is inserted along the long axis of the navicular bone, and a second kerf pin is inserted parallel to the guide kerf pin along the long axis of the navicular bone from the distal end to the proximal end to prevent rotation of the fracture block. The position of the needle is checked under fluoroscopy, and the guide pin must be located in the middle of the navicular bone with its tip just below the proximal cortex. The screw length is determined by measuring the length of the guide pin inserted into the navicular bone (screw length = length of the pin 2L), drilling, tapping, and screwing. The Kirschner pin was withdrawn and the position of the screw, navicular, lunate and triangular bones were examined fluoroscopically in multiple positions.
One case of radial tuberosity was resected during surgery, and one case of ulnar tuberosity fracture was internally fixed with an incisional repositioning Kirschner pin.
After the operation, the forearm was fixed in a plaster brace and the wrist joint was placed in a dorsal extension position of 15°. 3 weeks later, the plaster brace was removed, and the Kirschner pins fixing the radius and lunar bone were removed for functional exercise. 8 weeks later, the remaining Kirschner pins were removed.
III. Follow-up methods: Objective functional evaluation of the hand included wrist mobility, hand grip strength, and the degree of wrist pain after exertion. wrist mobility included wrist flexion and extension, and ulnar radial deviation movement. The grip strength of both hands was measured with a Jamar grip strength device. Pain level was measured by visual analogue scales (VAS). Total wrist function was evaluated using the Cooney scale.
At follow-up, frontal and lateral wrist radiographs were taken to observe the healing of the navicular bone and to measure the radial and navicular lunar angles as well as the lunar triangular bone spacing.
The patient-derived functional questionnaire upper limb functional rating scale was also used in this study for patient self-evaluation of the degree of preoperative and postoperative wrist function limitation, with a DASH value of 0 indicating completely normal function and 100 indicating no function at all.
IV. Statistical treatment: the data of this group were statistically processed and expressed as X±s.
Results
Eight patients underwent follow-up examinations at an average of 14 months (7-35 months) after surgery. Two patients developed postoperative infection at the skin of the keratoplasty needle penetration, which was cured with the application of antibiotics. one case had complete recovery of finger sensation in preoperative median nerve carpal tunnel syndrome.
Wrist pain values were 15.4±5.7 after weight-bearing and 9.5±2.2 at rest. wrist flexion and extension mobility was 76º±14º, 60% of the contralateral mobility; ulnar radial deviation was 50º±12º, 70% of the contralateral. The grip strength of the affected side was 27±8K, which was 70% of the contralateral side.
Cooney score results were excellent in 3 cases, good in 2 cases, moderate in 2 cases and poor in 1 case, with a mean score of 76±11. The DASH value was 27±10.
X-ray examination revealed that all 8 cases of navicular fractures healed without traumatic arthritis and no lunar osteonecrosis. The navicular lunar angle was (54±9)º , the radial lunar angle was (9±3)º , and the lunar triangle spacing was (1.9±0.5)mm.
Discussion
Fresh perilunar dislocation of the navicular bone is a high-energy injury that severely affects the functional recovery of the wrist joint and can lead to traumatic carpal arthritis, decreased wrist motion, extensor tendon rupture, and chronic carpal tunnel syndrome. The prerequisite for restoring the function of the wrist joint is the anatomical healing of the navicular bone and the restoration of the normal wrist joint axis. In the past, the treatment of periprosthetic dislocation of the navicular bone mostly used external fixation with closed reset plaster brackets, but external fixation with plaster brackets was difficult to achieve anatomical reset of the navicular bone and to completely restore the axis of the wrist joint, and the rate of non-healing of the navicular bone was high. We used compression screws for internal fixation of the navicular bone to anatomically reset the navicular bone under direct vision, and to anatomically reset the lunar bone, triangular bone, and the position between the skull and the lunar bone, creating conditions for postoperative functional recovery.
There are many approaches to the perilunar dislocation, including the palmar approach, dorsal approach and combined palmar-dorsal approach. We appreciate that the dorsal approach has obvious advantages, as it can reveal the navicular bone, the lunar bone and the triangular bone as well as the important intercalary ligament and the lunotriangular ligament at the same time, while the palmar approach only reveals the palmar ligament, but the intercalary ligament and the lunotriangular ligament cannot be revealed.
In the past, the perilunar dislocation via the navicular bone mostly focused on the repositioning and healing of the navicular bone. With the in-depth study of the anatomy and biomechanics of the wrist joint in recent years, it was found that the interlunar ligament, lunotriquetral ligament and radial navicular ligament play an important role in maintaining the stability of the wrist joint and restoring the function of the wrist joint. The anatomical repositioning of the navicular bone is as important as the normalization of the wrist joint axis in the treatment of perilunate dislocations via the navicular bone. The intrinsic ligament of the wrist joint is small, and direct suturing is sometimes difficult. Some scholars have reported that bone anchors are used to repair injuries to the intrinsic ligament of the wrist joint, with good clinical follow-up results. We anatomically repositioned the triangular bone and the lunate bone and then used internal fixation with a kyphotic pin for 8 weeks, and clinical follow-up revealed that the wrist joint axis could be restored to normal. In addition, we also found that the perilunar dislocation not only had lunar triangular ligament injury but also had other intrinsic ligament injuries in the wrist joint, and we found two cases with interlunar ligament injury, which suggested that the interlunar ligament injury should be checked at the same time during the incision and repositioning to avoid missing the diagnosis. Herzberg and Forissier reported two cases of transverse perilunar dislocation with injury to the navicular lunar interosseous ligament and a widening of the distance between the navicular and lunar bones at the time of follow-up.
Hildebrand [8] reported a significant manifestation of carpal arthritis after transosseous perilunate dislocation, with 9 of 18 cases showing carpal arthritis. However, the formation of osteoarthritis was not found in the follow-up of this study, which may be related to the short postoperative observation period in this group.
The duration of postoperative external fixation of perilunate dislocation via the navicular bone was closely related to the postoperative functional recovery, and a significant difference in the functional recovery of the wrist joint between 4 weeks of postoperative external fixation and 5 weeks of external fixation was reported. Changqing et al. reported 4 weeks of postoperative external fixation, and Knoll et al. reported 6-8 weeks of postoperative external fixation with a plaster rest. Since we used compression screws to fix the navicular bone for early activity, the duration of external fixation in our group was 3 weeks, and after 3 weeks, the kerf pins of the radius and lunate bone were removed and the radial wrist joint began to move, while the other joints were still fixed with kerf pins.
Hildebrand et al. reported 22 cases of trans navicular perilunate dislocation, and 37 months after internal fixation with incisional repositioning screws, the wrist flexion and extension mobility and wrist strength reached 57% and 73% of the contralateral side, respectively. Herzberg and Forissier reported 14 patients with trans navicular perilunate dislocation, and the Mayo wrist score was 79 points, and the flexion and extension mobility was 54 º Sotereanos et al. reported that flexion-extension activity could be restored to the contralateral side by 70%, and strength by 77%. The results of our follow-up did not differ from those reported by the above authors. In the present study, in addition to the medically derived wrist function evaluation form, the patient-derived function evaluation form was also used to completely and accurately evaluate the functional recovery.
In conclusion, early incisional repositioning and Herbert screw fixation can achieve anatomical repositioning and healing of the navicular bone, restore the wrist joint axis, and thus better restore the function of the wrist joint.