Magnetically driven antegrade intramedullary lengthening nails for tibial lengthening.

Aims: As an alternative to external fixators, intramedullary lengthening nails (ILNs) can be employed for distraction osteogenesis. While previous studies have demonstrated that typical complications of external devices, such as soft-tissue tethering, and pin site infection can be avoided with ILNs, there is a lack of studies that exclusively investigated tibial distraction osteogenesis with motorized ILNs inserted via an antegrade approach. Methods: A total of 58 patients (median age 17 years (interquartile range (IQR) 15 to 21)) treated by unilateral tibial distraction osteogenesis for a median leg length discrepancy of 41 mm (IQR 34 to 53), and nine patients with disproportionate short stature treated by bilateral simultaneous tibial distraction osteogenesis, with magnetically controlled motorized ILNs inserted via an antegrade approach, were retrospectively analyzed. The median follow-up was 37 months (IQR 30 to 51). Outcome measurements were accuracy, precision, reliability, bone healing, complications, and patient-reported outcome assessed by the Limb Deformity-Scoliosis Research Society Score (LD-SRS-30). Results: A median tibial distraction of 44 mm (IQR 31 to 49) was achieved with a mean distraction index of 0.5 mm/day (standard deviation 0.13) and median consolidation index of 41.2 days/cm (IQR 34 to 51). Accuracy, precision, and reliability were 91%, 92%, and 97%, respectively. New temporary range of motion limitations occurred in 51% of segments (34/67). Distraction-related equinus deformity treated by Achilles tendon lengthening was the most common major complication recorded in 16% of segments (11/67). In 95% of patients (55/58) the distraction goal was achieved with 42% unplanned additional interventions per segment (28/67). The median postoperative LD-SRS-30 score was 4.0 (IQR 3.6 to 4.3). Conclusion: Tibial distraction osteogenesis using motorized ILNs inserted via an antegrade approach appears to be a reliable and precise procedure. Temporary joint stiffness of the knee or ankle should be expected in up to every second patient. A high rate and wide range of complications of variable severity should be anticipated.

Morphology of the knee after guided growth using tension-band devices: a retrospective multicenter study of 222 limbs and 285 implants.

BACKGROUND AND PURPOSE: Temporary hemiepiphysiodesis by tension-band devices is commonly applied to correct angular limb deformities in children. We aimed to evaluate knee joint morphology after guided growth using these devices. PATIENTS AND METHODS: In a retrospective multicenter study we analyzed standardized anteroposterior long-leg radiographs of 222 limbs (285 implants) of patients treated by temporary hemiepiphysiodesis with either eight-Plates or FlexTacks for coronal angular deformities of the knee joint between 2013 and 2019. Femoral floor angle (FFA), femoral notch-intercondylar distance (FNID), and tibial roof angle (TRA) were measured pre- and postoperatively to assess the central knee joint morphology. Statistical exploratory analyses were performed using linear mixed models, t-tests, Wilcoxon signed-rank test, and Mann-Whitney U test. RESULTS: 217 FlexTacks (femur 106, tibia 111) in 104 children and 68 eight-Plates (femur 61, tibia 7) in 35 children were identified. Median time period under growth guidance was 11 months (range 4-42). No statistically significant change in the FFA was detected (eight-Plate: P = 0.2; FlexTack: P = 0.3). A statistically significant difference of the FNID was found in the eight-Plate group (P = 0.02), but not in the FlexTack group (P = 0.3). While TRA increased in both groups, a statistical significance was observed only in the FlexTack group (P < 0.01). CONCLUSION: We found minor but clinically irrelevant changes in knee morphology after the treatment.

Radiographic reference values of the central knee anatomy in 8-16-year-old children.

BACKGROUND AND PURPOSE: For correction of leg-length discrepancy or angular deformity of the lower limb in skeletally immature patients temporary or permanent (hemi-)epiphysiodesis can be employed. These are reliable treatments with few complications. Recently, radiographic analysis of treatment-related alterations of the central knee anatomy gained interest among pediatric orthopedic surgeons. To date the comparison and adequate interpretation of potential changes of the central knee anatomy is limited due to the lack of defined standardized radiographic references. We aimed to establish new reference values of the central knee anatomy. PATIENTS AND METHODS: A retrospective analysis of calibrated longstanding anteroposterior radiographs of 254 skeletally immature patients with a chronological age ranging from 8 to 16 years was conducted. The following radiographic parameters were assessed: (1) femoral floor angle, (2) tibial roof angle, (3) width at femoral physis, and (4) femoral notch-intercondylar distance. RESULTS: All observed radiographic parameters were normally distributed with a mean age of 12.4 years (standard deviation [SD] 2, 95% confidence interval [CI] 12.2-12.6). Mean femoral floor angle was 142° (SD 6, CI 141.8-142.9), mean tibial roof angle was 144° (SD 5, CI 143.7-144.1), mean width at femoral physis was 73 mm (SD 6, CI 72.8-73.9), and mean femoral notch-intercondylar distance was 8 mm (SD 1, CI 7.5-7.7). The estimated intraclass correlation coefficient values were excellent for all measurements. CONCLUSION: This study provides new radiographic reference values of the central knee anatomy for children between 8 and 16 years and we suggest considering values within the range of 2 SD as the physiological range.

Establishing Construct Validity of a Novel Simulator for Guide Wire Navigation in Antegrade Femoral Intramedullary Nailing.

Background: Antegrade femoral intramedullary nailing (IMN) is a common orthopedic procedure that residents are exposed to early in their training. A key component to this procedure is placing the initial guide wire with fluoroscopic guidance. A simulator was developed to train residents on this key skill, building off an existing simulation platform originally developed for wire navigation during a compression hip screw placement. The objective of this study was to assess the construct validity of the IMN simulator. Methods: Thirty orthopedic surgeons participated in the study: 12 had participated in fewer than 10 hip fracture or IMN related procedures and were categorized as novices; 18 were faculty, categorized as experts. Both cohorts were instructed on the goal of the task, placing a guide wire for an IM nail, and the ideal wire position reference that their wire placement would be graded against. Participants completed 2 assessments with the simulator. Performance was graded on the distance from the ideal starting point, distance from the ideal end point, wire trajectory, duration, fluoroscopy image count, and other elements of surgical decision making. A two-way ANOVA analysis was used to analyze the data looking at experience level and trial number. Results: The expert cohort performed significantly better than the novice cohort on all metrics but one (overuse of fluoroscopy). The expert cohort had a more accurate starting point and completed the task while using fewer images and less overall time. Conclusion: This initial study shows that the IMN application of a wire navigation simulator demonstrates good construct validity. With such a large cohort of expert participants, we can be confident that this study captures the performance of active surgeons today. Implementing a training curriculum on this simulator has the potential to increase the performance of the novice level residents prior to their operating on a vulnerable patient. Level of Evidence: III.

Antegrade Intramedullary Femoral Lengthening and Distal Temporary Hemiepiphysiodesis for Combined Correction of Leg Length Discrepancy and Coronal Angular Deformity in Skeletally Immature Patients.

Leg length discrepancies (LLD) are frequently associated with coronal malalignment. Temporary hemiepiphysiodesis (HED) is a well-established procedure for the correction of limb malalignment in skeletally immature patients. For treatment of LLD > 2 cm, lengthening with intramedullary devices gains increasing popularity. However, no studies have investigated the combined application of HED and intramedullary lengthening in skeletally immature patients. This retrospective single-center study evaluated the clinical and radiological outcomes of femoral lengthening with an antegrade intramedullary lengthening nail combined with temporary HED performed in 25 patients (14 females) between 2014 and 2019. Temporary HED through the implantation of flexible staples of the distal femur and/or proximal tibia was either performed prior (n = 11), simultaneously (n = 10) or subsequently (n = 4) to femoral lengthening. The mean follow-up period was 3.7 years (±1.4). The median initial LLD was 39.0 mm (35.0-45.0). Twenty-one patients (84%) presented valgus and four (16%) showed varus malalignment. Leg length equalization was achieved in 13 of the skeletally mature patients (62%). The median LLD of the eight patients with residual LLD > 10 mm at skeletal maturity was 15.5 mm (12.8-21.8). Limb realignment was observed in nine of seventeen skeletally mature patients (53%) in the valgus group, and in one of four patients (25%) in the varus group. Combining antegrade femoral lengthening and temporary HED is a viable option to correct LLD and coronal limb malalignment in skeletally immature patients; however, achieving limb length equalization and realignment may be difficult in cases of severe LLD and angular deformity, in particular.

Guided growth: angular deformity correction through temporary hemiepiphysiodesis with a novel flexible staple (FlexTack).

Temporary hemiepiphysiodesis (HED) is applied to children and adolescents to correct angular deformities (ADs) in long bones through guided growth. Traditional Blount staples or two-hole plates are mainly used for this indication. Despite precise surgical techniques and attentive postoperative follow-up, implant-associated complications are frequently described. To address these pitfalls, a flexible staple was developed to combine the advantages of the established implants. This study provides the first results of guided growth using the new implant and compares these with the established two-hole plates and Blount staples. Between January 2013 and December 2016, 138 patients (22 children, 116 adolescents) with genu valgum or genu varum were treated with 285 flexible staples. The minimum follow-up was 24 months. These results were compared with 98 patients treated with 205 two-hole plates and 92 patients treated with 535 Blount staples. In long-standing anteroposterior radiographs, mechanical axis deviations (MADs) were measured before and during treatment to analyze treatment efficiency. The evaluation of the new flexible staple was performed according to the idea, development, evaluation, assessment, long-term (IDEAL) study framework (Stage 2a). Overall, 79% (109/138) of patients treated with flexible staples achieved sufficient deformity correction. The median treatment duration was 16 months (interquartile range (IQR) 8 to 21). The flexible staples achieved a median MAD correction of 1.2 mm/month/HED site (IQR 0.6 to 2.0) in valgus deformities and 0.6 mm/month/HED site (IQR 0.2 to 1.5) in varus deformities. Wound infections occurred in 1%, haematomas and joint effusions in 4%, and implant-associated complications in 1% of patients treated with flexible staples. Valgus AD were corrected faster using flexible staples than two-hole plates and Blount staples. Furthermore, the median MAD after treatment was lower in varus and valgus AD, fewer implant-associated complications were detected, and reduced implantation times were recorded using flexible staples. The flexible staple seems to be a viable option for guided growth, showing comparable or possibly better results regarding correction speed and reducing implant-associated complications. Further comparative studies are required to substantiate these findings.

A clinical and radiological matched-pair analysis of patients treated with the PRECICE and STRYDE magnetically driven motorized intramedullary lengthening nails.

AIMS: Distraction osteogenesis with intramedullary lengthening devices has undergone rapid development in the past decade with implant enhancement. In this first single-centre matched-pair analysis we focus on the comparison of treatment with the PRECICE and STRYDE intramedullary lengthening devices and aim to clarify any clinical and radiological differences. METHODS: A single-centre 2:1 matched-pair retrospective analysis of 42 patients treated with the STRYDE and 82 patients treated with the PRECICE nail between May 2013 and November 2020 was conducted. Clinical and lengthening parameters were compared while focusing radiological assessment on osseous alterations related to the nail's telescopic junction and locking bolts at four different stages. RESULTS: Osteolysis next to the telescopic junction was observed in 31/48 segments (65%) lengthened with the STRYDE nail before implant removal compared to 1/91 segment (1%) in the PRECICE cohort. In the STRYDE cohort, osteolysis initially increased, but decreased or resolved in almost all lengthened segments (86%) after implant removal. Implant failure was observed in 9/48 STRYDE (19%) and in 8/92 PRECICE nails (9%). Breakage of the distal locking bolts was found in 5/48 STRYDE nails (10%) compared to none in the PRECICE cohort. Treatment-associated pain was generally recorded as mild and found in 30/48 patients (63%) and 39/92 (42%) in the STRYDE and PRECICE cohorts, respectively. Temporary range of motion (ROM) limitations under distraction were registered in 17/48 (35%) segments treated with the STRYDE and 35/92 segments (38%) treated with the PRECICE nail. CONCLUSION: Osteolysis and periosteal reaction, implant breakage, and pain during lengthening and consolidation is more likely in patients treated with the STRYDE nail compared to the PRECICE nail. Temporary ROM limitations during lengthening occurred independent of the applied device. Implant-related osseous alterations seem to remodel after implant removal.Cite this article: Bone Joint J 2023;105-B(1):88-96.

LIMB-Q Kids-German Translation and Cultural Adaptation.

(1) Purpose: Lower limb deformities can have a severe impact on health-related quality of life (HRQL). LIMB-Q Kids is a new patient-reported outcome measure (PROM) aiming to elucidate the experience of 8-18-year-old patients before, during and after treatment, and to measure the different aspects of HRQL. The aim of this study was to translate and culturally adapt LIMB-Q Kids to German. (2) Methods: The International Society for Pharmacoeconomics and Outcomes Research (ISPOR) guidelines were followed. Three forward translations, a backward translation, an expert panel meeting with eight participants, and twenty cognitive debriefing interviews led to the final German version of LIMB-Q Kids. (3) Results: In the forward translations, 4/159 items were difficult to translate, and 2/159 items in the backward translation differed from the original English version. Cognitive debriefing interviews with 20 patients identified 7/159 items that were difficult to comprehend/answer, and 2 of these items were changed. (4) Conclusions: Lower limb deformities can have a great impact on children, and it is important to measure and consider the impact on HRQL. In order to be able to use PROMs in different countries, conceptually equivalent translations and cultural adaptations should be performed in order to ensure comprehensibility. The final German version of LIMB-Q Kids is ready for use in an international field test.

Preliminary results of two novel devices for epiphysiodesis in the reduction of excessive predicted final height in tall stature.

BACKGROUND: In the treatment of tall stature, the reduction of excessive predicted final height can either be achieved by hormonal treatment or surgically by temporary (tED) or permanent (pED) epiphysiodesis. The present study evaluates the preliminary results of two novel devices for tED and pED around the knee to reduce the predicted final height. MATERIALS AND METHODS: A retrospective analysis was performed to evaluate the clinical and radiographic outcome after bilateral epiphysiodesis for the treatment of tall stature. A cohort of 34 patients (16 girls, 18 boys) who underwent either tED or pED between 2015 and 2020 were eligible for analysis based on the electronic patient records and picture archiving and communication system of our orthopaedic teaching hospital. tED was conducted in 11 patients (32%) through bilateral implantation of four RigidTacks™ (Merete, Berlin, Germany) around the knee. Twenty-three patients (68%) received pED, performed with an EpiStop™ trephine (Eberle, Wurmberg, Germany). The mean overall follow-up time was 2.9 years. RESULTS: The mean age at surgery was 12.3 years in girls and 13.2 years in boys. Patients had a mean body height of 175.2 cm in girls and 184.7 cm in boys at surgery. The mean predicted final height was 191.4 cm in girls and 210.4 cm in boys. At the last follow-up, 26 patients (76.5%) had achieved skeletal maturity. The mean height of skeletally mature patients was 187.2 cm in girls and 198.5 cm in boys. A mean reduction of the predicted final height of 5.9 cm in girls and 8.7 cm in boys was achieved, corresponding to a reduction in remaining growth of 46% in girls and 38% in boys. Secondary frontal plane deformities of the knee were detected in 5/11 patients (45.5%) in the tED group and 1/23 treatments (4.3%) in the pED group. CONCLUSIONS: tED and pED have both proven to be efficient at achieving growth inhibition to reduce excessive predicted height. However, tED has been associated with an increased risk of secondary angular deformities of the knee. Furthermore, the risk of implant-related complications and the necessity of a subsequent surgical intervention for implant removal have led our study group to abandon tED when treating tall stature. Long-term results of both procedures are pending.

German Translation and Cross-Cultural Adaptation of the Limb Deformity-Scoliosis Research Society (LD-SRS) Questionnaire.

BACKGROUND: Patient-reported outcome measures are gaining increasing importance in clinical research and quality control. Clinical impairment through limb deformities can appear in various forms. This study aimed at translating and culturally adaptating the Limb Deformity-Scoliosis Research Society (LD-SRS) patient-reported outcome measure (PROM) into German by following the scientific rigor of the cross-cultural adaptation process as well as ensuring the reliability of the translated version. The LD-SRS is applicable in children and adults. METHODS: The translation was performed in accordance with the creators of the LD-SRS following the Professional Society for Health Economics and Outcomes Research (ISPOR) guidelines for translation and cultural adaptation. Two forward translations were performed, and after a consensus meeting, a professional translator translated the PROM back to English. The creators reviewed the back translation of the preliminary German version. Thirty patients with upper and lower limb deformities participated in cognitive debriefing interviews. The version was proofread and, finally, the test-retest reliability was estimated. RESULTS: The mean age was 19 years (range 6-61). Twenty-six patients (87%) completed the retest after 6 days (range 3-26). The internal consistency was estimated with a Cronbach's alpha of 0.96 (range 0.94-0.97), and the intraclass correlation was 0.92 (range 0.89-0.94), indicating an excellent reliability. The scores were normally distributed. Thereafter, the German version was proofread and finalized. CONCLUSIONS: The German translation and cross-cultural adaptation of the LD-SRS score resulted in a high reliability and internal consistency. The German LD-SRS score is readily usable and may be applied in future studies of German-speaking limb deformity patients.

Callus distraction for brachymetatarsia - A comparison between an internal device and the external fixator.

BACKGROUND: Symptomatic patients with severe brachymetatarsia are commonly treated with callus distraction using external mini-fixator (EF) or internal device (ID). This study points out advantages and limitations of both methods comparing clinical and radiographical parameters. METHODS: Retrospective analysis of 21 metatarsal bones in twelve patients. Twelve metatarsals were treated with ID (Genos Mini), nine with EF (MiniRail). RESULTS: Mean lengthening distance was 17.3 mm using EF and 11.7 mm using ID (p = 0.016). Adverse results were observed in 89% of metatarsals treated with EF and in 33% treated with ID (p = 0.011). Postoperative surgical intervention was required in 33% using EF compared to 0% using ID (p = 0.031). Mean total German Foot Function Index (FFI-T) improved from 49 to 33 using EF and from 47 to 22 using ID (p < 0.001). CONCLUSION: CD is a reliable surgical treatment for BMT. Surgeons should be aware of implant-related advantages and complications when counseling patients about treatment options.

What Are the Risks and Functional Outcomes Associated With Bilateral Humeral Lengthening Using a Monolateral External Fixator in Patients With Achondroplasia?

BACKGROUND: Many patients with achondroplasia experience functional impairments because of rhizomelic upper extremities (proximal limb shortening). Bilateral humeral lengthening may overcome these functional limitations, but it is associated with several risks, such as radial nerve palsy and insufficient bone regeneration. Only a few studies have reported on patient satisfaction and functional outcome after humeral lengthening in patients with achondroplasia. Furthermore, the reported numbers of adverse events associated with lengthening procedures using external fixators vary widely. QUESTIONS/PURPOSES: (1) Does bilateral humeral lengthening with a monolateral external fixator in patients with achondroplasia reliably improve patient function and autonomy, and what proportion of patients achieved at least 8 cm of humeral lengthening? (2) What adverse events occur after bilateral humeral lengthening with monolateral external fixators? METHODS: Between 2011 and 2019, 44 patients underwent humeral lengthening at our institution. Humeral lengthening was performed in patients with severe shortening of the upper extremities and functional impairments. In humeri in which intramedullary devices were not applicable, lengthening was performed with monolateral external fixators in 40 patients. Eight patients were excluded because they underwent unilateral lengthening for etiologies other than achondroplasia, and another four patients did not fulfill the minimum study follow-up period of 2 years, leaving 28 patients with bilateral humeral lengthening to treat achondroplasia available for analysis in this retrospective study. The patients had a median (interquartile range) age of 8 years (8 to 10), and 50% (14 of 28) were girls. The median follow-up time was 6 years (4 to 8). The median humeral lengthening was 9 cm (9 to 10) with a median elongation of 73% (67% to 78%) from an initial median length of 12 cm (11 to 13). To determine whether this treatment reliably improved patient function and autonomy, surgeons retrospectively evaluated patient charts. An unvalidated retrospective patient-reported outcome measure questionnaire consisting of nine items (with answers of "yes" or "no" or a 5-point Likert scale) was administered to assess the patient's functional improvement in activities of daily living, physical appearance, and overall satisfaction, such that 45 points was the highest possible score. The radiographic outcome was assessed on calibrated radiographs of the humerus. To ascertain the proportion of adverse events, study surgeons performed a chart review and telephone interviews. Major complications were defined as events that resulted in unplanned revision surgery, nerve injury (either temporary or permanent), refracture of the bone regenerate, or permanent functional sequelae. Minor complications were characterized as events that resolved without further surgical interventions. RESULTS: On our unvalidated assessment of patient function and independence, all patients reported improvement at their most recent follow-up compared with scores obtained before treatment (median [IQR] 24 [16 to 28] before surgery versus 44 [42 to 45] at latest follow-up, difference of medians 20 points, p < 0.001). A total of 89% (25 of 28) of patients achieved the desired 8 cm of lengthening in both arms. A total of 50% (14 of 28) of our patients experienced a major complication. Specifically, 39% (11 of 28) had an unplanned reoperation, 39% (11 of 28) had a radial nerve palsy, 18% (5 of 28) had a refracture of the regenerate, and 4% (1 of 28) concluded treatment with a severe limb length discrepancy. In addition, 82% (23 of 28) of our patients experienced minor complications that resolved without further surgery and did not involve radial nerve symptoms. Radial nerve palsy was observed immediately postoperatively in eight of 13 segments, and 1 to 7 days postoperatively in five of 13 segments. The treatment goal was not achieved because of radial nerve palsy in 5% (3 of 56) of lengthened segments, which occurred in 7% (2 of 28) of patients. Full functional recovery of the radial nerve was observed in all patients after a median (IQR) of 3 months (2 to 5). Refractures of bone regenerates were observed in 11% (6 of 56) of humeri in 18% (5 of 28) of patients. Of those refractures, 1 of 6 patients was treated nonsurgically with a hanging cast, while 5 of 6 patients underwent revision surgery with intramedullary rodding. CONCLUSION: Most patients with achondroplasia who underwent humeral lengthening achieved the treatment goal without permanent sequelae; nonetheless, complications of treatment were common, and the road to recovery was long and often complicated, with many patients experiencing problems that were either painful (such as refracture) or bothersome (such as temporary radial nerve palsy). However, using a subjective scale, patients seemed improved after treatment; nevertheless, robust outcomes tools are not available for this condition, and so we must interpret that finding with caution. Considering our discoveries, bilateral humeral lengthening with a monolateral external fixator should only be considered in patients with severe functional impairments because of rhizomelic shortening of the upper extremities. If feasible, internal lengthening devices might be preferable, as these are generally associated with higher patient comfort and decreased complication rates compared with external fixators. LEVEL OF EVIDENCE: Level IV, therapeutic study.

Total joint replacement of the hip and knee in patients with arthrogryposis multiplex congenita: a report of six joints.

INTRODUCTION: Arthrogryposis multiplex congenita (AMC) is a rare congenital condition that leads to severe joint contractures and deformities. As painful joint dysplasia and degeneration might develop over time, total joint replacement (TJR) can be a potential treatment option for these patients. The aim of this study is to investigate functional results, implant survivorship and potential complications in patients with AMC who undergo hip or knee arthroplasty. MATERIALS AND METHODS: We retrospectively identified six TJR in three patients at a single centre performed between 2006 and 2019. The median patient age at surgery was 23 years and the median follow-up period was 69 (IQR 55-99) months. We analysed surgical technique, implant survivorship and complications as well as functional outcome determined by pain reported on the Numerical Rating Scale (NRS), patient-reported outcome scores [Oxford Hip Score (OHS), Harris Hip score (HHS), Oxford Knee Score (OKS)], range of motion and ambulatory status. Depending on data distribution means with ranges and median with interquartile range were compared with the Wilcoxon signed rank test or Student's t test. The level of significance was defined at < 0.05. RESULTS: In hips, the mean range of motion in flexion/extension (52° vs. 85°, p = 0.014) and in rotation (28° vs. 68°, p = 0.02) as well as mean pain score on the NRS (8.5 vs. 0, p = 0.001), OHS (9 vs. 26, p = 0.031) and HHS (17 vs. 52, p = 0.007) significantly improved. In knees, mean range of motion (55° vs. 93°, p = 0.403), mean pain score on the NRS (0 vs. 7) and the OKS (2 vs. 21) also improved. While the ambulatory status did not change, the patients who were wheelchair dependent reported less problems with transfers to a bed or chair and the patient who ambulated reported an improved walking distance. One total knee arthroplasty (TKA) underwent revision for an acute, late infection 155 months following the initial surgery. CONCLUSIONS: TJR is a safe procedure in patients with AMC that effectively improves function and reduces pain irrespective of preoperative ambulatory status.

What Are the Potential Benefits and Risks of Using Magnetically Driven Antegrade Intramedullary Lengthening Nails for Femoral Lengthening to Treat Leg Length Discrepancy?

BACKGROUND: Limb lengthening with magnetically driven intramedullary lengthening nails is a fast-developing field and represents an alternative to external fixators. Although previous studies have assessed the application of magnetically driven intramedullary lengthening nails, these studies have been heterogenous regarding the nailing approach, the bone treated, and the implant type; they also have analyzed relatively small patient groups at short follow-up durations. QUESTIONS/PURPOSES: (1) Is femoral lengthening with magnetically driven antegrade intramedullary lengthening nails accurate and precise? (2) What are the most common complications of treatment? (3) What factors are associated with unplanned additional surgery? METHODS: We retrospectively analyzed the longitudinally maintained database of our orthopaedic teaching hospital to identify all patients who underwent surgery for leg length discrepancy (LLD) between October 2014 and April 2019. In total, we surgically treated 323 patients for LLD of 2 cm or more. Of those 55% (177 of 323) were treated with distraction osteogenesis with magnetically driven intramedullary lengthening nails, 18% (59 of 323) with external fixation, and 27% (87 of 323) with epiphysiodesis around the knee. Based on that, 29% (93 of 323) of patients underwent unilateral femoral distraction osteogenesis with magnetically driven antegrade femoral lengthening nails and were eligible for analysis. No patient was excluded, and 3% (3 of 93) were lost before the minimum study follow-up of 2 years, leaving 97% (90 of 93) for analysis. Patients with a distal femoral deformity were treated via a retrograde femoral approach (10% [33 of 323]) or with external fixators (3% [10 of 323]) and were not included in this study. Distraction osteogenesis with magnetically driven intramedullary lengthening nails was not considered for patients with deep tissue infection, those with bone dimensions considered to be too small in relation to the available implants, and for patients younger than 8 years. This study included 90 patients (44 females, 43 left femora) treated for a median (interquartile range) preoperative LLD of 39 mm (32 to 52) at a median age of 15 years (14 to 17). The same limb lengthening system was applied in all patients. The median (IQR) follow-up was 35 months (24 to 78). Data were acquired through a chart review performed by someone not involved in the surgical care of the included patients. Data acquisition was supervised and curated by two of the involved surgeons. Accuracy was calculated as 100 - [(achieved distraction in mm - planned distraction in mm) / (planned distraction in mm) x 100] and precision as 100 - (relative standard deviation of accuracy). Treatment-associated complications were summarized descriptively and characterized as complications resulting in unplanned additional surgery or those not resulting in unplanned surgery. To analyze the risk of unplanned additional surgery by entity, we calculated odds ratios (ORs) comparing the incidence of unplanned additional surgery in the different entity cohorts with the idiopathic LLD cohort as a reference. By calculating ORs, we analyzed the risk for unplanned additional surgery depending on sex, age, surgery time, and previous lengthening. Due to the lack of long-term evidence about motorized lengthening nails remaining in situ and concerns about potential implant-related adverse effects, removal was routinely scheduled 1 year after consolidation. For implant removal, 92% (83 of 90) of patients underwent planned additional surgery, which was not recorded as an adverse event of the treatment. Ninety-seven percent (87 of 90) of patients completed lengthening with the implant remaining in situ until the end of distraction. The median (IQR) distraction length was 37 mm (30 to 45) with a median distraction index of 0.9 mm/day (0.7 to 1.0) and median consolidation index of 31 days/cm (25 to 42). RESULTS: The calculated accuracy and precision were 94% and 90%, respectively. In total, 76% (68 of 90) of our patients experienced complications, which resulted in 20% (18 of 90) of patients undergoing unplanned additional surgery. The most common complication overall was adjustment of the distraction rate in 27% (24 of 90) of patients (faster: 16% [14 of 90]; slower: 11% [10 of 90]) and temporary restriction of knee motion, which occurred in 20% (18 of 90) of our patients and resolved in all patients who experienced it. The most serious complications were bacterial osteomyelitis and knee subluxation, which occurred in 3% (3 of 90) and 1% (1 of 90) of our patients, respectively. With the numbers available, we found only one factor associated with an increased likelihood of unplanned additional surgery: Patients with postinfectious LLD had higher odds of unplanned additional surgery than patients with idiopathic LLD (7% [1 of 15] versus 50% [3 of 6], OR 14.0 [95% CI 1.06 to 185.49]; p = 0.02). However, we caution readers this finding is fragile, and the confidence interval suggests that the effect size estimate is likely to be imprecise. CONCLUSION: Femoral distraction osteogenesis with magnetically driven antegrade intramedullary lengthening nails appears to be an accurate and reliable treatment for femoral lengthening. However, depending on the etiology, a high risk of unplanned additional surgery should be anticipated, and a high proportion of patients will experience temporary joint stiffness. We recommend close orthopaedic follow-up and physiotherapy during treatment. This treatment of LLD can be considered alongside other nails, external fixators, and epiphysiodesis. Multicenter studies comparing this with other approaches are needed. LEVEL OF EVIDENCE: Level IV, therapeutic study.

Current strategies for the treatment of solitary and aneurysmal bone cysts: A review of the literature.

This review of the literature aims to compare the etiology, the pathogenesis, the clinical diagnostics and the relevant treatment options of two different types of cystic bone lesions: the solitary bone cyst (SBC) and the aneurysmal bone cyst (ABC). Whereas the clinical symptoms and the radiographic appearance can be similar, the diagnostic pathway and the treatment options are clearly different. The solitary bone cyst (SBC) represents a tumor-like bone lesion, occurring most frequently in the humerus and femur in children and adolescents. Pain caused by intercurrent pathological fractures is often the first symptom, and up to 87% of the cysts are associated with pathological fractures. In the majority of cases SBCs can be treated conservatively, especially in the upper extremity. However, if a fracture is completely dislocated, joint affecting, unstable or open, surgical treatment is necessary. Pain under weight bearing or regaining the ability to mobilize after fracture timely can necessitate surgical treatment in SBCs affecting the lower extremity. Spontaneous resolution can be seen in rare cases. The aneurysmal bone cyst (ABC) is a benign, locally aggressive tumor that occurs in childhood and early adulthood. It usually affects the metaphysis of long bones but can also occur in the spine or the pelvis. ABC can be primary but also secondary to other bone pathologies. The diagnosis has to be confirmed by biopsy and histopathological examinations. With cytogenetic studies and the detection of specific translocations of the ubiquitin-specific protease (USP) 6 gene primary ABCs can be differentiated from secondary ABCs and other bone lesions. Among various modalities of treatment i.e. en bloc resection, intralesional curettage with adjuvants, embolization or the systemic application of denosumab, intralesional sclerotherapy using polidocanol is an effective and minimally invasive treatment of primary ABCs.

Growth arrest: leg length correction through temporary epiphysiodesis with a novel rigid staple (RigidTack).

AIMS: Temporary epiphysiodesis (ED) is commonly applied in children and adolescents to treat leg length discrepancies (LLDs) and tall stature. Traditional Blount staples or modern two-hole plates are used in clinical practice. However, they require accurate planning, precise surgical techniques, and attentive follow-up to achieve the desired outcome without complications. This study reports the results of ED using a novel rigid staple (RigidTack) incorporating safety, as well as technical and procedural success according to the idea, development, evaluation, assessment, long-term (IDEAL) study framework. METHODS: A cohort of 56 patients, including 45 unilateral EDs for LLD and 11 bilateral EDs for tall stature, were prospectively analyzed. ED was performed with 222 rigid staples with a mean follow-up of 24.4 months (8 to 49). Patients with a predicted LLD of ≥ 2 cm at skeletal maturity were included. Mean age at surgery was 12.1 years (8 to 14). Correction and complication rates including implant-associated problems, and secondary deformities as well as perioperative parameters, were recorded (IDEAL stage 2a). These results were compared to historical cohorts treated for correction of LLD with two-hole plates or Blount staples. RESULTS: The mean LLD was reduced from 25.2 mm (15 to 45) before surgery to 9.3 mm (6 to 25) at skeletal maturity. Implant-associated complications occurred in 4/56 treatments (7%), and secondary frontal plane deformities were detected in 5/45 legs (11%) of the LLD cohort. Including tall stature patients, the rate increased to 12/67 legs (18%). Sagittal plane deformities were observed during 1/45 LLD treatments (2%). Compared to two-hole plates and Blount staples, similar correction rates were observed in all devices. Lower rates of frontal and sagittal plane deformities were observed using rigid staples. CONCLUSION: Treatment of LLD using novel rigid staples appears a feasible and promising strategy. Secondary frontal and sagittal plane deformities remain a potential complication, although the rate seems to be lower in patients treated with rigid staples. Further comparative studies are needed to investigate this issue. Cite this article: Bone Joint J 2021;103-B(8):1428-1437.

Evaluation of different treatment modalities for fractured and non-fractured simple bone cyst: A single-center review of 68 patients.

ABSTRACT: Simple bone cysts (SBCs) occur most frequently in the proximal aspect of the humerus and femur in growing age and are associated with intercurrent pathological fractures in up to 87%. Therapeutic management of SBCs remains controversial. The aim of this study was to examine the outcome of conservative and various surgical treatment modalities considering the specific anatomic location and integrity of the SBC.In this retrospective study, we analyzed 68 cases of SBCs who underwent a conservative or surgical treatment between 2009 and 2020 with a mean follow-up of 30.1 months. The epidemiological characteristics, complications, clinical, and radiographic outcome after conservative or surgical treatment were assessed.The study includes 50 male (73.5%) and 18 female (26.5%) patients with a mean age of 9.1 years. The most common locations were the proximal humerus (69.2%, n = 47) and femur (16.2%, n = 11). In 43 cases (63.2%; upper limb n = 40, lower limb n = 3) a pathological fracture occurred. Fifty patients (73.5%; upper limb n = 40, lower limb n = 10) underwent a conservative treatment. In 11 cases (16.2.1%; upper limb n = 4, lower limb n = 7) an intralesional curettage and defect reconstruction with bone substitute without stabilization were performed. Five patients (7.3%; upper limb n = 4, lower limb n = 1) received an osteosynthesis, in two cases (2.9%; upper limb 1; lower limb 1) combined with an intralesional curettage and defect reconstruction with bone substitute. All 32 pathological fractures treated conservatively (upper limb n = 31, lower limb n = 1) healed within 6 weeks; 17/43 patients (39.5%) suffered at least one second fracture. After intralesional curettage and defect reconstruction with bone substitute local recurrence was observed in 5/13 cases (38.5%). Spontaneous consolidation, at least partially, was observed in three cases (4.4%) following conservative treatment after fracture. No relevant secondary angular or torsional deformity was observed after treatment.The majority of SBCs can be treated conservatively, especially in the upper extremity. However, if a fracture is completely dislocated, joint affecting, unstable or open, surgical treatment is necessary. Load-dependent pain or the inability to mobilize timely after fracture can necessitate surgical treatment in SBCs affecting the lower extremity. Spontaneous resolution, especially after fracture, can be seen in rare cases.

Focal osteolysis and corrosion at the junction of Precice Stryde intramedullary lengthening device : preliminary clinical, radiological, and metallurgic analysis of 57 lengthened segments.

AIMS: This study aims to enhance understanding of clinical and radiological consequences and involved mechanisms that led to corrosion of the Precice Stryde (Stryde) intramedullary lengthening nail in the post market surveillance era of the device. Between 2018 and 2021 more than 2,000 Stryde nails have been implanted worldwide. However, the outcome of treatment with the Stryde system is insufficiently reported. METHODS: This is a retrospective single-centre study analyzing outcome of 57 consecutive lengthening procedures performed with the Stryde nail at the authors' institution from February 2019 until November 2020. Macro- and microscopic metallographic analysis of four retrieved nails was conducted. To investigate observed corrosion at telescoping junction, scanning electron microscopy (SEM) and energy dispersive x-ray spectroscopy (EDX) were performed. RESULTS: Adjacent to the nail's telescoping junction, osteolytic changes were observed in bi-planar radiographs of 20/57 segments (35%) after a mean of 9.5 months (95% confidence interval 7.2 to 11.9) after surgery. A total of 8/20 patients with osseous alterations (40%) reported rest and ambulation pain of the lengthened segment during consolidation. So far, 24 Stryde nails were retrieved and in 20 (83%) macroscopic corrosion was observed at the nail's telescoping junction. Before implant removal 11/20 radiographs (55%) of lengthened segments with these 20 nails revealed osteolysis. Implant retrieval analysis by means of SEM showed pitting and crevice corrosion. EDX detected chromium as the main metallic element of corrosion. CONCLUSION: Patients are exposed to the risk of implant-related osteolysis of unclear short- and long-term clinical consequences. The authors advocate in favour of an early implant removal after osseous consolidation. Cite this article: Bone Joint Res 2021;10(7):425-436.

Staged reconstruction of unilateral neglected hip dislocation through total hip arthroplasty and subsequent intramedullary femoral lengthening.

BACKGROUND AND PURPOSE: Total hip arthroplasty (THA) is a successful approach to treat unilateral symptomatic neglected hip dislocation (NHD). However, the extensive leg length discrepancy (LLD) can hereby only be partially corrected. In case of residual LLD of more than 2 cm, subsequent femoral lengthening can be considered. PATIENTS/MATERIAL/METHODS: Retrospective analysis of clinical data and radiographs of five patients (age 38.1 (28-51) years) with unilateral NHD who underwent THA with (n = 3) or without (n = 2) subtrochanteric shortening osteotomy (SSO) and secondary intramedullary femoral lengthening through a retrograde magnetically-driven lengthening nail (follow-up 18.4 (15-27) months). RESULTS: LLD was 51.0 (45-60) mm before and 37.0 (30-45) mm after THA. Delayed bone union at one SSO site healed after revision with autologous bone grafting and plate fixation. Subsequent lengthening led to leg length equalisation in all patients. Complete consolidation was documented in all lengthened segments. CONCLUSION: Staged reconstruction via THA and secondary femoral lengthening can successfully be used to reconstruct the hip joint and equalise LLD. The specific anatomical conditions have to be taken into consideration when planning treatment, and patients ought to be closely monitored.