Factors that affect the healing index of metacarpal lengthening: a retrospective study

Novel Use of an Internal Distractor for Metacarpal Lengthening

BACKGROUND

In patients who have had proximal digit amputation, metacarpal distraction osteogenesis is an option to improve digital length and function. One drawback is that traditional external distraction devices are large and cumbersome; the option of a low-profile internal device is therefore appealing. Internal distractors are commonly used in craniofacial reconstruction, but use in the hand has not been reported. We describe a case series of the novel use of an internal distractor in metacarpal lengthening.

METHODS

In this single-center case series, patients who underwent metacarpal distraction by the senior author using a uniplanar internal distractor were reviewed, and indications, outcomes, and complications were analyzed.

RESULTS

There were 5 cases in 4 patients (age range: 7-33 years). Indications were traumatic amputation in 4 cases and congenital hypoplasia in 1. All were successfully distracted, with a mean final length gain of 1.3 cm (range: 1.0-1.7 mm). Mean time from device placement to consolidation was 3.5 months. Complications included activation arm site infection in 2 cases, both occurring after the distraction period, necessitating device removal before full consolidation. In these cases, the device was removed after the distraction period and replaced with a Kirschner wire for stabilization through the consolidation period.

CONCLUSIONS

Metacarpal distraction was successfully achieved with an internal distraction device. Although infection was common, it occurred after the distraction period and did not preclude length gain. We feel that this low-profile device offers advantages over cumbersome external devices typically used for metacarpal lengthening.

Metacarpal Lengthening Using a Mini-Ring Ilizarov Device for Thumb Reconstruction

PURPOSE

To explore the results of using the mini-ring Ilizarov external fixator for thumb metacarpal lengthening and its compatibility with a simultaneous groin flap.

METHODS

From May 2016 to June 2019, 17 adult patients with thumb loss were treated with metacarpal lengthening using a mini-ring Ilizarov device. The device was composed of 2 rings, threaded rods, nuts, and K-wires (diameter, 1.5 mm). Of these patients, 6 also underwent simultaneous groin flap transfer. Lengthening was started 3 days after surgery at a rate of 0.66 mm/d. The pedicle of the groin flap was divided 1 month after the surgery. The healing index (days per cm), which denotes the number of days the external fixator is attached to the bone per centimeter of length gained, was used to evaluate the lengthening efficiency.

RESULTS

The patients were observed for 21.9 ± 9.0 months. The lengthening continued for 29.1 ± 4.5 days, resulting in an additional length of 1.9 ± 0.3 cm.

CONCLUSIONS

The mini-ring Ilizarov external fixator is a simple device for primary metacarpal lengthening. This device can be used with a groin flap for single-stage lengthening of injured thumbs with bone exposure.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic IV.

A comparative study of bone union and nonunion during distraction osteogenesis

BACKGROUND

The clinical characteristics of bone nonunion during distraction osteogenesis (DO) were rarely discussed. This study was employed to specify the difference between bone union and nonunion during DO.

METHODS

The patients with bone lengthening were recruited in our study. The bone union cases indicated the ones that remove the external fixator successfully, whereas the bone nonunion represented the bridging callus did not appear even after 9 months (an absence of bridging callus for at least three out of four cortices on plain radiographs) that needs autogenous bone transplantation. The differences in the pixel value ratio (PVR) growth of regenerated callus, lengthening index (LI), healing index (HI), external fixation index (EFI) and blood biochemical indexes between bone union and nonunion were analyzed.

RESULTS

A total of 8 bone nonunion and 27 bone union subjects were included in this study. The PVR growth in bone nonunion was significantly lower than that in bone union (0.19 ± 0.06 vs. 0.32 ± 0.16, P = 0.048). Interestingly, the HI and EFI in bone nonunion was significantly higher than that in bone union (62.0 ± 31.4 vs. 37.0 ± 27.4, P = 0.036; 75.0 ± 30.9 vs. 49.9 ± 16.1, P = 0.006). However, no significant difference with regard to LI was identified (0.76 ± 0.52 vs. 0.77 ± 0.32, P = 0.976). Moreover, the circulating level of urea and lymphocyte count in bone union was significantly lower than that in bone nonunion (4.31 ± 1.05 vs. 5.17 ± 1.06, P = 0.049; 2.08 ± 0.67 vs. 2.73 ± 0.54, P = 0.018). On the contrary, the circulating level of magnesium in bone union was significantly higher than that in bone nonunion (0.87 ± 0.07 vs. 0.80 ± 0.07, P = 0.014).

CONCLUSION

Compared to the bone union, the PVR growth was significantly lower, whereas the HI and EFI was significantly higher in the bone nonunion. Moreover, the circulating level of urea, magnesium and lymphocyte count was also different between these two. Therefore, the PVR, HI and EFI seems to be reliable and sensitive indicators to reflect the bone nonunion during DO, which might be considered in bone lengthening. Further prospective studies are still needed to elaborate the concerned issues.

Brachymetacarpia and brachymetatarsia: do we need to operate?

Brachymetacarpia and brachymetatarsia are rare congenital presentations denoted by shortening of metacarpals and metatarsals respectively, in which the deformity usually presents around childhood/early adolescence.

The aetiology is usually congenital besides several other syndromic or endocrinologic associations.

Cosmetic issues such as absence of a normal-looking knuckle while making a fist or disruption of finger-tip curvature besides functional issues are the main indications for surgical intervention in brachymetacarpia.

In the foot, apart from cosmetic issues, pain due to transfer metatarsalgia as well as callosities along with toe deformities which lead to difficulty of using footwear are the main indications for intervention.

Lengthening of the affected bone, either acute with grafting or gradual, is the mainstay of treatment. Gradual lengthening can be either single-stage as in callotasis, or two-stage where the primary procedure is followed by bone grafting after the length has been achieved.

Adolescence, specifically between 12 and 15 years, is the preferred period for surgical intervention in these cases.

Cite this article: EFORT Open Rev 2021;6:15-23. DOI: 10.1302/2058-5241.6.200087

The effectiveness of distraction lengthening in traumatic hand amputation with Ilizarov mini fixator

BACKGROUND

Bone distraction lengthening has been used for hand reconstruction. The healing process involved in this technique is affected by many factors. Here, the effectiveness and rates of healing of the phalanges and the metacarpals were evaluated in cases of traumatic finger amputation treated using an Ilizarov mini-fixator.

METHODS

Fourteen phalanges and twelve metacarpals in 15 patients (13 males and 2 females) were treated with distraction lengthening using an Ilizarov mini-fixator between 2014 and 2017. All the digits had been subjected to traumatic amputation, and shortening of the remaining digit had occurred despite successful replantation in some cases. The healing indices of phalanges and metacarpals were analyzed.

RESULTS

The mean patient age was 42.8 years. The mean lengthening of the phalanges was 13.3 mm, while that of the metacarpals was 26.5 mm. The mean consolidation times were 144.4 days for the phalanges and 154.1 days for the metacarpals. The mean healing indices of the phalanges and metacarpals were 114 days/cm and 60 days/cm, respectively. No bone grafts were needed in any of the patients.

CONCLUSIONS

Distraction lengthening of the digits after traumatic amputation is an effective procedure for hand reconstructive surgery for either the phalanges or the metacarpals and is less invasive than other techniques. The rate of healing of the metacarpals is two times faster than that of the phalanges.

Metacarpal Lengthening in Adults With Brachymetacarpia

BACKGROUND

Metacarpal lengthening by distraction osteogenesis has been well documented in pediatric patients but limited in older patients. Fewer studies have assessed the success of the procedure through outcome measure scores. The purpose of this study is to assess the outcomes of distraction osteogenesis in skeletally mature adults with brachymetacarpia and patients' perspectives on their satisfaction through outcome measure scores.

METHODS

Retrospective chart review of a consecutive series of metacarpal lengthenings for the treatment of brachymetacarpia was performed. Key parameters collected include starting metacarpal length, amount lengthened, range of motion of metacarpophalangeal joint, type of fixator used, distraction time, and total time in fixator. Relevant comorbidities and complications encountered were recorded as well. The Body Image Quality of Life Inventory (BIQLI) and Limb Deformity Modified Scoliosis Research Society (LD-SRS) score were given to evaluate patients' perspectives on their satisfaction of surgery.

RESULTS

Seven metacarpal lengthenings were performed in 4 adult females (average age: 22.8 years) between 2005 and 2016. The average amount lengthened was 1.5 cm (range, 1.2-2.1 cm), corresponding to a mean percent lengthening of 44.4% (range, 33.3%-57.1%). The mean distraction rate was 0.432 mm/day (range, 0.286-0.724 mm/day). The mean distraction time was 38 days (range, 28-55 days). External fixation index was 71.8 days/cm (range, 53.5-99.2 days/cm). No functional loss was observed.

CONCLUSIONS

Progressive distraction osteogenesis can obtain functionally successful results and improvement in aesthetics and body image without severe complications in skeletally mature adults with brachymetacarpia.

[Application of Ilizarov technique in functional reconstruction of thumb degloving injury after amputation]

Objective

To investigate the effectiveness of Ilizarov technique in reconstruction of thumb function in patients with thumb degloving injury after amputation.

Methods

Between June 2011 and September 2016, 9 cases of thumb degloving injury were treated with amputation and Ilizarov technology. There were 8 males and 1 female with an age of 18-52 years (mean, 34.7 years). The amputation plane was the level of the metacarpophalangeal joint in 5 cases, the level of the proximal metacarpophalangeal joint in 2 cases, and the level of the base of the proximal phalanx in 2 cases (the length of proximal phalanx was less than 1 cm). After amputation, the affected finger was shorter than the healthy finger by 4.0-7.5 cm, with an average of 5.7 cm. On the fifth day after operation, the semi-loop external fixation extender was applied for extension, which was extended by 0.5 mm per day, and was extended once every 6 hours.

Results

After bone lengthening surgery, the first web space elevation and contracture occurred in 8 cases. Six of them were treated with the amputation of the inner muscle of the thumb and the "Z" forming technique, postoperative thumb function recovered well; the remaining 2 cases rejected plasty. All 9 patients were followed up 14-47 months, with an average of 33 months. Bone lengthening time was 64-122 days, with an average of 86 days. The lengthening length of bone was 3.0-5.9 cm, with an average of 4.1 cm, and the average lengthening length was 71.9% of the average shortened length. The fixation time of external fixator was 169-342 days, with an average of 231 days. The healing index was 43.2-59.1 days/cm, with an average of 53.4 days/cm. One case showed prolonged mineralization delay and recovered after "accordion" treatment. Bone healing was finally achieved in all patients, with the healing time ranging from 169 to 342 days, with an average of 231 days. No replantation internal fixation and flexion contracture occurred. The two-point discrimination of extended fingertip was similar to that of normal fingertip. The grip strength reached 53%-89% of the healthy side; the kneading force reached 59%-91% of the healthy side.

Conclusion

The application of Ilizarov technology to extend the thumb metacarpal lengthening is a good method to reconstruction the thumb function after degloving injury.

Rehabilitation post-distraction osteogenesis for brachymetacarpia: a case report

Distraction osteogenesis for brachymetacarpia has been described in several small case series and single case reports, but the rehabilitation required to optimize outcomes has not been reported. We present a case report describing the hand rehabilitation program of a 13-year-old girl with congenital brachymetacarpia who underwent distraction osteogenesis of the third metacarpal. Intense weekly hand therapy including desensitization, scar massage, range of motion exercises and splinting was essential up to 28 weeks postoperatively to address the progressive changes in the anatomical structures. At final follow-up, she had full active range of motion, no functional deficits in grasp or in-hand manipulation skills and resumed her participation in competitive baton twirling. Patient and family satisfaction with outcome was high. However, better education regarding the progressive symptoms with distraction and daily challenges of wearing an external fixator would have improved the overall experience. With a strong family commitment to rehabilitation and thorough patient education, distraction osteogenesis for brachymetacarpia has the potential to improve functional and aesthetic outcome in the hand.

LEVEL OF EVIDENCE

V.

Bone Lengthening in the Pediatric Upper Extremity

➤Bone lengthening has been used successfully for several congenital and acquired conditions in the pediatric clavicle, humerus, radius, ulna, and phalanges.➤Common indications for bone lengthening include achondroplasia, radial longitudinal deficiency, multiple hereditary exostosis, brachymetacarpia, symbrachydactyly, and posttraumatic and postinfectious growth arrest.➤Most authors prefer distraction rates of <1 mm/day for each bone in the upper extremity except the humerus, which can safely be lengthened by 1 mm/day.➤Most authors define success by the amount of radiographic bone lengthening, joint motion after lengthening, and subjective patient satisfaction rather than validated patient-related outcome measures.➤Bone lengthening of the upper extremity is associated with a high complication rate, with complications including pin-track infections, fixation device failure, nerve lesions, nonunion, fracture of regenerate bone, and joint dislocations.

Digital ray reconstruction through distraction osteogenesis: a retrospective study of 82 rays with long-term follow-up

PURPOSE

The aim of the present study was to present the long-term radiographic results with distraction osteogenesis in traumatic or congenital length discrepancies of long bones of the hand.

METHODS

The medical records and radiographs of 65 consecutive patients (27 metacarpals and 55 phalanges) with either traumatic or congenital digital length discrepancies were retrospectively reviewed. The mean follow-up was 8.2 years. The mean distraction period was 21 days with a distraction rate of 4×0.25mm/day. Callus consolidation was obtained in all patients.

RESULTS

The bones were lengthened by a mean amount of 17.5mm, with a mean increase in bone length of 68±17.3%. The mean healing index was 28.57 days/cm. Ray reconstruction with callus distraction can be applied effectively in skeletally immature or mature patients with congenital differences of the hand or amputated fingers.

CONCLUSION

A distraction rate of 1mm/day proved to be a safe rate of lengthening in both metacarpals and phalanges.

The significance of serum phosphate level on healing index and its relative effects in skeletally immature and mature patients with hypophosphatemic rickets

The aim of this study was to find out the ideal cut-off level of phosphate for safe healing when deformity correction and concomitant lengthening are indicated in the two different skeletal maturity groups of patients with rickets. Thirty-nine hypophosphatemic rickets patients were selected for the study and were divided into two groups: 27 skeletally immature (group IM) and 12 skeletally mature (group M). The outcomes were evaluated with respect to the healing index (HI), laboratory findings, and complications with the mean follow-up of 5.1 years (range, 3.1-7.9). The healing index (HI) of group IM was 1.44 month/cm and HI of group M was 1.68 month/cm. The negative correlation between the level of serum phosphate and HI in group M (coefficient=-0.94) was evaluated to be less than the correlation in group IM (coefficient=-0.50), indicating that the HI is more likely to be affected by serum phosphate in group M than in group IM. Preoperative serum phosphate levels of 2.3 mg/dL and 2.6 mg/dL were analyzed to be the cut-off values of group IM and group M, respectively, in which the cut-off points divided the series into two groups having the most significantly different HI.

Percutaneous distraction lengthening in brachymetacarpia

Brachymetacarpia is a condition manifesting a shortened metacarpal that is caused by early closure of the epiphyseal plate and believed to arise idiopathically. The correction for brachymetacarpia is usually for cosmetic reasons as brachymetacarpia does not impair function. The literature indicates several different approaches to lengthening digits, including single-stage lengthening and rapid distraction lengthening with a bone graft. However, gradual distraction is the preferred method due to excellent cosmetic outcomes and few postoperative complications. This article reports a case of brachymetacarpia treated with distraction lengthening using a minimally invasive, percutaneous approach. A 16-year-old girl presented with a shortened left ring finger and underwent surgery to correct the deformity. The left ring finger measured 12 mm shorter than her right ring finger; however, there was normal mobility at the joints. In the operating room, an external fixator was attached using 4 self-drilling, self-tapping pins through several 3-mm skin incisions. The total fixation time was 14 weeks; however, the achieved length of 12 mm was achieved 6 weeks postoperatively. The healing index of the fixation period was 81 days/cm. The postoperative course and fixation period were uneventful, with no complications except for 2 pin infections that were treated with oral antibiotics. The method of gradual distraction lengthening in this case successfully achieved the desired length and yielded an excellent cosmetic result.

Nonvascularized toe phalangeal transfer and distraction lengthening for symbrachydactyly

Symbrachydactyly describes a spectrum of congenital hand differences consisting of digital loss resulting in fused short fingers. As the principles for distraction lengthening have evolved, the technique of nonvascularized toe phalangeal transfer to the hand with shortened digits has provided patients with improved outcomes. Nonvascularized toe phalanx to hand transplant with distraction lengthening restores functional length to a skeletally deficient, poorly functioning hand while maintaining an overlying layer of vascular and sensate tissue. The primary goal is improvement of digital length to enhance mechanical advantage and prehension. We describe the technique of nonvascularized toe phalangeal transfer and distraction lengthening for symbrachydactyly, including the following steps: nonvascularized proximal toe phalanx harvest, toe phalanx transfer to hand, pin placement, osteotomy, and closure.