Induced membrane technique using enriched bone grafts for treatment of posttraumatic segmental long bone defects.

BACKGROUND: Reconstruction of posttraumatic bone defects represents a difficult challenge. The induced membrane technique is an effective two-stage procedure for bone defect reconstruction. To overcome the problems of autologous bone grafting, different graft substitutes have been investigated. The aim of the present study is to evaluate our clinical experience in reconstruction of critical posttraumatic bone defects using an induced membrane technique based on a combination of autologous graft and allograft (cancellous bone) enriched with platelet-rich plasma (PRP) and bone marrow concentrate aspirate (BMCA). MATERIALS AND METHODS: Between 2009 and 2014, we reconstructed 18 posttraumatic bone defects in 16 patients. Their average length was 6.4 cm (range 1.6-13.2 cm). The defect location was the femur in nine cases (50%), the tibia in eight (44%) cases, and the humerus in one (6%) case. In all cases, we used a combination of autologous and cancellous allograft graft enriched with PRP and BMCA. Bone fixation was achieved using intramedullary nailing in 2 cases (11%), plating in 15 cases (66%), and external fixation in 1 case (6%). RESULTS: Both clinical and radiographic union were achieved in 13 (72%) cases (13 patients). Five (28%) cases (four patients) developed nonunion. Nonunion was observed in two of eight (25%) tibial defects and in three (33%) of nine femoral defects (ns). Three of 4 (75%) double defects had delayed union, whereas 2 of 14 (14%) single defects did not heal (p = 0.016). The average length of the 13 defects that united was 6 cm (range 1.6-11.8 cm), while the length of the 5 defects that did not unite was 10.3 cm (range 6-13.2 cm) (p = 0.009). CONCLUSIONS: In this series using an induced membrane technique based on a combination of autograft and allograft enriched with BMCA and PRP, the healing rate was lower than in other series where autologous bone graft alone was employed. Nonunion was more frequent in longer and double defects. Further research aimed at developing effective alternative options to autogenous cancellous bone graft is desirable. LEVEL OF EVIDENCE: III.

Postsurgical osteomyelitis caused by Enterobacter sakazakii in a healthy young man.

Enterobacter sakazakii, a Gram-negative rod-shaped bacterium, is a rare cause of invasive infections (meningitis, sepsis, necrotizing enterocolitis) with high death rates (40-80%), primarily in newborns. In contrast to the high number of cases in newborns, infants and children, there are only a few reported cases of E. sakazakii infections in adults, generally in subjects with pre-existing conditions such as neoplasms, and just one osteomyelitis of the foot. We report a confirmed case of postsurgical osteomyelitis of the femur caused by E. sakazakii in a young otherwise healthy man.

Lateral collateral ligament reconstruction using a semitendinosus graft.

We evaluated 13 reconstructions of the lateral collateral ligament (LCL) of the knee associated with a reconstruction of the ACL (n=6) and PCL (n=7). In all cases the LCL was reconstructed using a semitendinosus tendon graft through a tunnel in the fibular head and fixed in anatomical insertion of LCL at lateral femoral condyle. Patients were evaluated using the IKDC form. Lateral joint opening and posterior tibial translation were studied by radiographic stress views. The follow-up average was of 60 months (38-93). In the ACL group five patient were symptoms free while one reported moderate pain after strenuous activity. The lateral stress radiographs showed lateral joint opening of 0-2 mm in five knees, and 3-5 mm in one. In the PCL group four patients were symptom free while three complained mild to moderate pain or swelling. Lateral joint opening was 0-2 mm in six knees and 3-5 in one. External rotation at 30 degrees of flexion was 10 degrees in one and between 0-5 degrees in the remainder. Eleven of 13 patients returned to their preinjury level and two returned to one level lower. These findings indicate that the LCL can be successfully reconstructed with a free ST graft at the time of ACL or PCL reconstruction.

Patella resurfacing in total knee replacement: functional evaluation and complications.

Three different knee replacements, with three trochlear designs, were prospectively evaluated clinically and radiographically for patellar function and presence of patellar complications. They included the Insall-Burstein (IB) I and the IB-II (posterior cruciate ligament substituting) and the Meniscal Bearing Knee (MBK; posterior cruciate ligament recession). The trochlea of the IB-I was short and shallow with an anterior sharp edge of the intercondylar box (later modified to a smoother edge) and the femoral component had a prominent "shoulder." In the IB-II the trochlea was deeper to allow for soft tissue clearance. In the MBK the trochlea was more prolonged, with R and L components and the "shoulder" was less prominent. In all the cases the patella was resurfaced with an all polyethylene dome prosthesis. Knees with tibiofemoral problems were excluded. From the data of the present study the following conclusions can be drawn: (a) The most frequent problem was impingement (clunks) with the early version of the IB-I. Smoothening of the anterior edge significantly reduced the incidence of clunks to 5% in the modified IB I. (b) With the IB-II deepening the trochlea for soft tissue clearance improved the degree, not the incidence of clunks (4.5%), compared to the modified IB I. (c) With the MBK clunks were very rare and patellar function improved. (d) Throughout the three series patellar stress fractures and instability were rare and loosening or wear not evident. (e) Normal function (including stairs ascending and descending) can be expected in over 80% of category A patients. (f) Of the various radiological parameters only patella baja was correlated with symptoms in the IB prostheses. (g) We still prefer the dome design because is more tolerant and with cold flow may better conform to the trochlea increasing contact area.

Clastogenic effects of two tyrosine kinase inhibitors, tyrphostin 23 and tyrphostin 46, on a transformed (CHO-K1) and on a primary embryonic chinese hamster cell line (CHE).

Protein tyrosine kinases (PTKs) play fundamental roles in signal transduction pathways. Many proliferative diseases are characterized by deregulation of PTK activity, therefore PTKs appear as promising targets in the design of anticancer drugs. Tyrphostins are a family of synthetic compounds which efficiently target specific PTKs without competing for ATP and thus are much less cytotoxic with respect to conventional therapeutic agents. We tested two tyrphostin derivatives, Tyrphostin 23 and Tyrphostin 46, on a transformed (CHO-K1) and on a primary embryonic Chinese hamster cell line (CHE) to determine whether these compounds had a genotoxic effect. We found that the tyrphostins increased sister chromatid exchange frequency in both cell lines, but induced chromosomal aberrations only in the transformed CHO-K1 cell line when treatment was in the S phase of the cell cycle, and not in primary CHE cells. Such a result could have important therapeutic implications: it could mean that deregulation of signal transduction pathways in cells which already have a deficit in cell cycle control could cause chromosomal aberrations.

Femoral tunnel position in anterior cruciate ligament reconstruction using three techniques. A cadaver study.

The possibility of achieving correct deep femoral tunnel positioning during anterior cruciate ligament (ACL) reconstruction with the double incision technique (DI), the transtibial technique (TT), and the anteromedial technique (AM) was evaluated in 30 cadaver knees. A reference hole was made just deep to the insertion of the anteromedial bundle of the ACL through an anteromedial arthrotomy. In the DI technique, a Kirshner wire was inserted outside-in using a rear entry C guide. In the TT and AM techniques, the K-wire was inserted inside-out through the tibial tunnel and through the arthrotomy, respectively. The reference hole could be achieved with each technique. Using lateral radiographs, the superficial aspect of the intra-articular exit of the femoral tunnel was found to be located on average at 36%, 36%, and 34% of the width of the condyles from the posterior margin (NS). None of the holes was more anterior than 40%. In conclusion, a deep femoral tunnel positioning could be achieved with each technique. The choice of technique must be based on the surgeon's preference and clinical results.

The relationship between the intercondylar roof and the tibial plateau with the knee in extension: relevance for tibial tunnel placement in anterior cruciate ligament reconstruction.

The relationship between the intercondylar roof and the tibial plateau with the knee in full extension was studied in 100 patients with a unilateral anterior cruciate ligament (ACL) lesion. A lateral view of both knees in full extension with superimposition of the femoral condyles was obtained with the fluoroscope. We found that, in the normal knee, the roof line intersects the tibial plateau (roof-plateau intersection ratio) at 31.5% (SD +/- 5%) of its width and at 33.9% (+/- 5.4%) in the ACL deficient knee (P < .001). The difference was attributable to a subtle anterior tibial displacement in the ACL-deficient knee. Multiple regression analysis showed a direct relationship between roof-plateau intersection ratio and the angle between roof line and tibial plateau (P = .0006). A direct relationship of borderline significance (P = .06) was present with the knee recurvatum measured clinically. In conclusion, the roof-plateau intersection ratio has a wide range of variability (22% to 41%). The larger the roof-plateau angle the more posterior the roof-plateau intersection ratio.

Arthroscopic meniscectomy for discoid lateral meniscus in children and adolescents: 10-year follow-up.

Seventeen adolescents underwent arthroscopic lateral meniscectomy for discoid lateral meniscus. The average age at surgery was 13.6 years (range: 5-18 years). The main preoperative symptom was pain in 16 knees and extension loss in 1 knee. At arthroscopy, 10 menisci were complete, 4 were incomplete, and 3 were Wrisberg type. Arthroscopic total meniscectomy was performed in the 3 Wrisberg types, 2 complete types, and 1 incomplete type. The remaining menisci underwent partial meniscectomy. The average follow-up was 10 years (range: 5-15 years). According to the Ikeuchi rating system, 12 knees were rated as excellent (no symptoms and full range of motion), 4 were rated as good (occasional pain), and 1 was rated as fair (patellofemoral pain in an obese patient). Radiographic evaluation showed development of minor osteophytes in the lateral compartment of 8 knees and <50% narrowing of the lateral joint space in 11 knees. No correlation was found between meniscal type, type of meniscectomy (partial or total), and clinical and radiographic results. Arthroscopic lateral meniscectomy for discoid lateral meniscus in adolescents was effective in relieving symptoms during a 10-year follow-up period. Longer follow-up is needed to ascertain the significance of the radiographic changes seen in this study.

Anatomic versus non-anatomic tibial fixation in anterior cruciate ligament reconstruction with bone-patellar tendon-bone graft.

We prospectively compared two series of 30 anterior cruciate ligament (ACL) reconstructions each where the bone-patellar tendon-bone graft was alternately fixed at the level of the tibial plateau (group A; anatomic fixation) or distal to the plateau level (group B; non-anatomic fixation). In group A, a 35-mm-long tibial tuberosity bone block was harvested. The distal 10-15 mm were resected and fixed proximally to the undersurface of the tendon to shorten it. After an average 18 months' follow-up, there were no significant differences between the two groups concerning subjective evaluation, symptoms, range of motion and objective stability. Tibial tuberosity pain was more frequent in group A (53% vs 17%, P = 0.01). Radiographic evaluation showed that tibial tunnel enlargement was less frequent in group A (23% vs 43%, P = 0.02). There was no correlation between tunnel enlargement and objective stability. In conclusion, fixation of the graft at the tibial plateau level did not improve objective stability in this study. Because of the greater technical difficulty and occurrence of tibial tuberosity pain, this technique is not recommended.

Arthroscopic-assisted anterior cruciate ligament reconstruction with the central third patellar tendon. A 5-8-year follow-up.

We reviewed 89 arthroscopically assisted patellar tendon anterior cruciate ligament (ACL) reconstructions for chronic isolated injuries with an average follow-up of 7 years (range 5.4 to 8.6 years). Pain was present in 7 knees (8%). Giving-way symptoms were reported by 7 patients (8%). A KT-2000 side-to-side difference over 5 mm at 30 lbs was recorded in 12 cases (16%). The pivot shift was glide in 17 cases (19%) and clunk in 10 (11%). A 3 degrees-5 degrees extension loss compared with the normal side was present in 20 knees (22%) and 6 degrees-10 degrees in 4 knees (4%). The intra-articular exit of the femoral tunnel was misplaced in the anterior 50% of the condyles along the roof of the notch in 10% of the knees. This positioning significantly (P = 0.003) increased the frequency of graft failure (62.5%) compared with the cases with a more posterior placement (graft failure 12%). An anterior position of the intra-articular exit of the tibial tunnel (in the anterior 15% of the sagittal width of the tibia) significantly (P = 0.01) increased the frequency of extension loss > 5 degrees. Medial meniscectomy was associated with a 35% incidence of narrowing of the medial joint space, which was significantly higher compared with knees with normal menisci (9%; P = 0.04) or with medial meniscal repair (7%; P = 0.05). In conclusion this study showed satisfactory anterior stability (KT-2000 side-to-side difference up to 5 mm and pivot absent or glide) in 83% of the knees. This percentage increases to 88% in the knees with a correct posterior and proximal femoral tunnel placement. Accuracy in tunnel positioning is essential for the success of ACL surgery. Meniscal repair was effective in decreasing joint space narrowing and should be attempted when possible.

Arthroscopically assisted semitendinosus and gracilis tendon graft in reconstruction for acute anterior cruciate ligament injuries in athletes.

We evaluated 69 arthroscopically assisted anterior cruciate ligament reconstructions for acute tears at an average followup of 60 months. We used a distally based single semitendinosus and gracilis tendon graft passed over the top and fixed to the femur. Combined medial collateral ligament lesions were seen in 30 knees, and they were repaired when found in the distal third (18 knees). The patients were instructed to recover motion preoperatively, and an early range of motion program was used postoperatively. At followup, symptoms of giving way were seen in five knees (7%). Graft failure was seen in seven knees (10%); failure was defined as a positive pivot shift (clunk or gross) or a side-to-side difference in anterior tibial displacement greater than 5 mm, as measured with a KT-1000 arthrometer. Permanent extension loss (3 degrees to 5 degrees) was found in two knees (3%). Patellofemoral crepitation was seen in eight knees (12%), but the condition was symptomatic in only one knee. Forty-six patients (67%) were active in pivoting sports before surgery and 37 (54%) remained active in these sports at followup. We concluded that this operation is simple, effective, and has a low complication rate. Further studies are necessary to elucidate if a stronger graft (e.g., a patellar tendon) would decrease the rate of graft failure without increasing complications.

The Insall-Burstein posterior stabilized total knee replacement in the valgus knee.

Sixty-seven Insall-Burstein (Zimmer Inc, Warsaw, Indiana) posteriorly stabilized total knee replacements were implanted in knees with a preoperative alignment > 10 degrees of valgus (average: 19.5 degrees). An anteromedial approach with release of the lateral ligaments of the femur was used. A lateral patellar release was necessary in 49% of cases. Fifty-one knees (76%) were reviewed with an average follow-up of 6 years. Pain at follow-up was absent or mild in all of the knees except one with aseptic loosening of the tibial and patellar components. The average flexion was 105 degrees. The results according to the Knee Society Rating System were excellent in 53%, good in 39%, fair in 6%, and poor in 2%. A patellofemoral "clunk" was present in three knees (6%), and one knee required arthroscopic debridment. The mechanical axis was within 5 degrees of neutral in 88%. A survivorship analysis was performed using failure requiring reoperation as the end point. There were four failures due to aseptic loosening, symptomatic lateral ligamentous instability, deep infection, and recurrent patellar dislocation. The patellar component had not been implanted in the knee with recurrent patellar dislocation due to severe bony erosion. The cumulative success rate was 95% at 10 years. These results indicate that release of the contracted lateral structures and implantation of a posteriorly stabilized prosthesis achieve a stable and well-aligned knee in 66 out of 67 knees. Attention must be paid to patellar tracking and realignment of the extensor mechanism.

Insall-Burstein posterior-stabilized knee prosthesis in rheumatoid arthritis.

The authors reviewed 65 Insall-Burstein (Zimmer, Warsaw, IN) total condylar posterior-stabilized knee prostheses in 50 patients with rheumatoid arthritis with a follow-up period of at least 5 years (range, 5-13 years). Forty-two knees in 31 patients were evaluated using the Knee Society knee and functional rating scores. Radiographic assessment was performed using standing long radiographs (hip to ankle). Radiolucent lines were studied using fluoroscopic-centered views. Excellent or good clinical results were obtained in 95% of the cases, and the average knee score improved from 22.5 to 90 points. No cases of radiologic loosening were observed. Incomplete radiolucent lines around the tibial component were detected in only 17% and were nonprogressive. Two patients developed hematogenous late deep infection, which required removal of the prosthesis in both, followed, at a second stage, by arthrodesis in one and prosthesis reimplantation in the other. Three knees (7%) had a painful impingement of the patella. Two of these were successfully reoperated with arthroscopic debridement of the peripatellar synovial tissues. Survivorship analysis, based on endpoints such as prosthesis removal for any cause or radiologic loosening (complete radiolucent line thicker than 1 mm, tilt, or subsidence of the component), showed a cumulative success rate of 96.2% at 13 years.

Results of surgical treatment of arthrofibrosis after ACL reconstruction.

We prospectively studied 31 knee arthrolyses performed for loss of motion after intra-articular anterior cruciate ligament (ACL) reconstruction. The arthrolysis was performed on average 10.6 months after the reconstruction (range 4-25). Seven knees were localized forms. They were treated with arthroscopic removal of a fibrous nodule and scar tissue anterior to the ACL, which was preserved. Twenty-four knees were global forms and treated arthroscopically (14) or in open procedure (10). Suprapatellar, medial, and lateral gutter adhesions were sectioned, and fibrous tissue was removed from the anterior compartment. A posteromedial and/or posterolateral capsulotomy was necessary in 7 knees. The ACL graft was nonfunctional and/or malpositioned in 19 knees. The results were evaluated with the IKDC form with an average follow-up of 3.5 years (range 1.5-7). Preoperatively the localized forms had an average extension loss of 11 degrees and an average flexion loss of 14 degrees compared to the opposite knee. At follow-up all the knees were satisfactory for symptoms. All except one achieved a satisfactory motion (within 5 degrees of extension loss and 15 degrees of flexion loss) and a satisfactory final result. Global forms had a greater preoperative flexion loss (average 34 degrees) and extension loss (average 17 degrees). At follow-up 58% were satisfactory for symptoms and 71% for arc of motion. However, the final result was satisfactory in only 37%. In conclusion, local forms have a good prognosis. In global forms motion may be improved by surgery, but the final result is downgraded by symptoms. Arthrolyses performed within 8 months from index operation had a better outcome.

Surgical treatment of recurrent dislocation of the patella.

Sixty-seven patients (69 knees) with recurrent patellar dislocation underwent either a lateral release (20 knees), a proximal realignment (14 knees), a distal realignment (16 knees), or a combined realignment (19 knees) procedure. Average respective followup was 8, 8, 6, and 4 years. Patients undergoing lateral release experienced a 40% recurrence of patellar dislocation. After a realignment procedure, redislocation was uncommon (4%), but pain and swelling were reported by 12% of the patients. Significant patellofemoral crepitation was present in 35% of the realignments. The congruence angle was corrected satisfactorily in the proximal realignments, but it remained abnormal in 25% of the distal realignments. The distance from the tuberosity to the sulcus was restored to normal by transposition of the tibial tuberosity, but remained abnormal in 36% of the proximal realignments. However, it did not preclude a good clinical result. Lateral release cannot be recommended for knees with severe dysplasia of the extensor mechanism. Proximal, distal, and combined realignments yielded similar clinical results. Retensioning of the medial structures and lateral release are effective in reducing the patella within the sulcus. Although transposition of the tuberosity is appealing, clinical advantages are less evident.

Arthroscopic drilling in juvenile osteochondritis dissecans of the medial femoral condyle.

Fourteen children affected by juvenile osteochondritis dissecans of the medial femoral condyle (16 knees) were treated by arthroscopic drilling of the lesion. The average age at operation was 12.8 years, and all the knees had open physes. Conservative treatment including restriction of activities had been unsuccessfully attempted in all cases for a period of > 1 year on average. At surgery each lesion was shown to have intact articular cartilage. All the lesions progressed to healing, and the patients were asymptomatic at an average of 56 months after the operation. Radiographic examination showed reconstitution of a normal or minimally flattened profile of the medial condyle. Arthroscopic drilling of the lesion in knees with juvenile osteochondritis dissecans and intact articular cartilage was effective to promote healing. The low morbidity and easy rehabilitation justify the procedure for these young patients when conservative measures fail.

Patellofemoral problems after intraarticular anterior cruciate ligament reconstruction.

A series of 226 anterior cruciate ligament (ACL) reconstructions were reviewed to determine the incidence of patellofemoral (PF) problems and the associated prognostic factors. Patients were divided into four groups according to the type of injury (acute or chronic) and operation (through an arthrotomy or arthroscopic assisted). The average follow-up period was 39 months. Overall there was a 5% incidence of PF crepitus with pain and/or swelling, and a further 20% of clear PF crepitus without pain. The change from open surgery and cast to arthroscopic surgery and early motion allowed a decrease of PF problems from 40% to 21% in acute injuries, but the difference was less marked in chronic knees. A deficit greater than 10% at the one-leg hop test was present in 75% of the knees with PF crepitus and pain. The height of the patella was increased in 5% and decreased in 17% of the knees. Patients with rehabilitation difficulties had the largest decrease in patella height, whereas a patella alta was more frequent after patellar tendon reconstruction. A significant correlation was found between PF problems and female gender, positive congruence angle, preoperative PF crepitation, rehabilitation difficulties, flexion loss greater than 10 degrees, extension loss greater than 5 degrees, and variation in the height of the patella. The importance of avoiding immobilization, rehabilitation difficulties, and permanent flexion or extension loss is emphasized.

Arthroscopic anterior cruciate ligament reconstruction with patellar tendon.

Anterior cruciate ligament reconstruction using a bone-patella tendon-bone free autologous graft was performed with an arthroscopic technique in 73 patients with chronic insufficiency. Sixty-nine (94.5%) were available for personal follow-up 3-5 years after the operation. Six patients (8%) had had postoperative difficulties in regaining a complete range of motion. Symptoms of giving-way were cured in 97% of the cases, and 89% had returned to vigorous activities. Residual anterior laxity (defined as pivot shift 2+, and/or Lachman 2+, and/or KT-1000 > 5 mm at the manual maximum) was found in 13% and was more frequent in patients with an uncorrected varus laxity. Patellofemoral crepitus was present in 17% of the knees and was associated with pain and/or swelling in a further 4%; it correlated with radiographic evidence of patellofemoral incongruence (p = 0.009). Comparison of the results with those of a previous series performed by arthrotomy revealed a decreased incidence of limited range of motion, severe patellar symptoms, and changes in patellar height. Stability was the same.

Long-term study of anterior cruciate ligament reconstruction for chronic instability using the central one-third patellar tendon and a lateral extraarticular tenodesis.

Forty-four patients with symptomatic chronic anterior cruciate ligament instabilities that had been reconstructed with the central one-third patellar tendon and a lateral extraarticular iliotibial band tenodesis were studied at an average followup of 7 years (range, 4 to 10). The cases with associated medial, lateral, or posterior laxity were not included, nor were the cases with more than minimal preoperative degenerative changes. The average age at surgery was 21 years (range, 16 to 33). A postoperative cast was used for 4 weeks. Satisfactory objective stability, which was defined as a KT-1000 side-to-side difference of up to 5 mm at the manual maximum test, was obtained in 37 (84%) of the patients. In 25 patients (57%), stability was restored within normal limits (less than or equal to 3 mm). No deterioration of the KT-1000 stability was noted at two follow-up visits performed by the same examiner (at an average of 4 and 7 years). A return to high-risk sports was possible in 27 (62%) of the patients. Difficulties in regaining a complete range of motion were recorded in 5 (11%) of the patients. A flexion contracture of 5 degrees to 7 degrees was also found in 5 patients. Significant patellofemoral symptoms were present in 4 patients (9%). A 5% to 11% shortening of the patella tendon was observed in 14 (32%) of the knees, but did not correlate with patellar problems. Moderate radiographic changes were noted in eight patients (18%) at followup and correlated with meniscectomy and pain. Overall satisfactory results were obtained in this initial experience in 29 (66%) of the patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Knowledge-based battery design of short-term tests based on dose information.

A construction of batteries of short-term tests (STTs) is described which is based on a classification of 73 chemicals in regard to their carcinogenicity. The 73 chemicals were studied within the U.S. National Toxicology Program (Ashby and Tennant, 1988). The batteries are validated using the classification of 35 additional chemicals. They are defined by logically structured combinations of rules. The single rules are defined by the z-scores of the logarithmic values of the limiting doses obtained from the 4 in vitro STTs used in the study by Ashby and Tennant. The limiting dose is defined as the lowest effective dose or the highest ineffective dose (Waters et al., 1987). The batteries are constructed by minimizing the number of disagreements with the classification by Ashby and Tennant. Compared with the results obtained from single STTs, 2 batteries of 3 STTs have higher concordances with the carcinogenicity data, namely 70% for the NTP data and 74-77% for the independent test data. In addition, a theoretical result shows that the proposed battery design, for a large enough learning set of chemicals, leads to results which are replicated with high probability on a large enough validation set. Based on the first results obtained with a limited number of chemicals it is concluded that the knowledge-based battery design is worth further development.