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BACKGROUND AND PURPOSE: Intramedullary bone-lengthening nails have become increasingly popular. The 2 most used and successful nails are the FITBONE and the PRECICE nails. Uniform reporting is lacking on complications of intramedullary bone-lengthening nails. The purpose was therefore to assess and categorize the complications of lower limb bone-lengthening nails and investigate risk factors.PATIENTS AND METHODS: We performed a retrospective review of patients operated on with intramedullary lengthening nails at 2 hospitals. We included only lower limb lengthening with FITBONE and PRECICE nails. Recorded patient data was patient demographics, nail information, and any complication. Complications were graded according to severity and origin classification. Complication risk factors were assessed with modified Poisson regression.RESULTS: 314 segments in 257 patients were included. The FITBONE nail was predominantly used (75%), and most of the lengthenings were performed in the femur (80%). 53% of the patients had complications. 269 complications were identified in 175 segments (144 patients). Device-related complications were most frequent (0.3 complications/segment), followed by joint complications (0.2 complications/segment). An increased relative risk was found for complications in the tibia compared with the femur and for age groups above 30 years compared with the 10-19 years group.CONCLUSION: Complications with intramedullary bone lengthening nails were more frequent than has previously been reported, with 53% of patients sustaining a complication. Future studies need to document the complications meticulously so that the true risk can be established.

Assessment of bone graft material efficacy is difficult in humans, since invasive methods like staged CT scans or biopsies are ethically unjustifiable. Therefore, we developed a novel large animal model for the verification of a potential transformation of synthetic bone graft substitutes into vital bone. The model combines multiple imaging methods with corresponding histology in standardized critical sized cancellous bone defect. Cylindrical bone voids (10 ml) were created in the medial femoral condyles of both hind legs (first surgery at right hind leg, second surgery 3 months later at left hind leg) in three merino-wool sheep and either (i) left empty, filled with (ii) cancellous allograft bone or (iii) a synthetic, gentamicin eluting bone graft substitute. All samples were analysed with radiographs, MRI, μCT, DEXA and histology after sacrifice at 6 months. Unfilled defects only showed ingrowth of fibrous tissue, whereas good integration of the cancellous graft was seen in the allograft group. The bone graft substitute showed centripetal biodegradation and new trabecular bone formation in the periphery of the void as early as 3 months. μCT gave excellent insight into the structural changes within the defects, particularly progressive allograft incorporation and the bone graft substitute biodegradation process. MRI completed the picture by clearly visualizing soft tissue ingrowth into unfilled bone voids and presence of fluid collections. Histology was essential for verification of trabecular bone and osteoid formation. Conventional radiographs and DEXA could not differentiate details of the ongoing transformation process. This model appears well suited for detailed in vivo and ex vivo evaluation of bone graft substitute behaviour within large bone defects.

Background and purpose — We noted several adverse events in patients in whom the first version of the STRYDE limb-lengthening nail (NuVasive Specialized Orthopaedics, San Diego, CA) had been implanted. Pain, osteolysis, periosteal reactions, and cortical hypertrophy at the nail junction were noted. Here, we present the analysis of 23 retrieved STRYDE implants. Materials and methods — We undertook visual inspection of the retrieved nails and screws, mechanical evaluation of the junction, micro-CT analyses, microscopic inspection of the bushing, screws, screw holes, and separated parts of the implants. Positive material identification (PMI) and energy-dispersive X-ray spectroscopy (EDS) were used to analyze the chemical composition. The hardness of the material was also investigated. Results — 20/23 retrieved nails had visible signs of corrosion, i.e., discoloration at the telescopic junction. Micro-CT verified corrosion attacks in 12/12 scanned bushings. Corrosion, predominantly mechanically assisted crevice corrosion, was observed at the locking screws and screw holes in 20/23 nails. Biological material inside the nail was observed in addition to oozing from the junction of 2 nails during hardware removal, which was experimentally reproducible. Notably, the mechanical construction of the bushing changed from PRECICE P2 to STRYDE nails. Interpretation — STRYDE nails are not hermetically sealed, and liquid can pass the bushing. Biodur 108 itself is corrosion resistant; however, mechanically assisted crevice corrosion of the bushing, locking screws, and screw holes may be aggravated due to manufacturing aiming for increased strength and hardness of the alloy. Observing several adverse events, we recently published a nationwide cross-sectional analysis of all 30 STRYDE limb- lengthening nails (NuVasive, Specialized Orthopedics, San Diego, CA) that were implanted in Denmark (Rölfing et al. 2021a). 27/30 STRYDE nails have now been removed and we present data from metallurgical analysis of 23 of the retrieved implants.

Background and purpose — In recent years motorized intramedullary lengthening nails have become increasingly popular. Complications are heterogeneously reported in small case series and therefore we made a systematic review of complications occurring in lower limb lengthening with externally controlled motorized intramedullary bone lengthening nails.Methods — We performed a systematic search in PubMed, EMBASE, and the Cochrane Library with medical subject headings: Bone Nails, Bone Lengthening, and PRECICE and FITBONE nails. Complications were graded on severity and origin.Results — The search identified 952 articles; 116 were full text screened, and 41 were included in the final analysis. 983 segments were lengthened in 782 patients (age 8–74 years). The distribution of nails was: 214 FITBONE, 747 PRECICE, 22 either FITBONE or PRECICE. Indications for lengthening were: 208 congenital shortening, 305 acquired limb shortening, 111 short stature, 158 with unidentified etiology. We identified 332 complications (34% of segments): Type I (minimal intervention) in 11% of segments; Type II (substantial change in treatment plan) in 15% of segments; Type IIIA (failure to achieve goal) in 5% of segments; and Type IIIB (new pathology or permanent sequelae) in 3% of segments. Device and bone complications were the most frequent.Interpretation — The overall risk of complications was 1 complication for every 3 segments lengthened. In 1 of every 4 segments, complications had a major impact leading to substantial change in treatment, failure to achieve lengthening goal, introduction of a new pathology, or permanent sequelae. However, as no standardized reporting method for complications exists, the true complication rates might be different. Background and purpose — In recent years motorized intramedullary lengthening nails have become increasingly popular. Complications are heterogeneously reported in small case series and therefore we made a systematic review of complications occurring in lower limb lengthening with externally controlled motorized intramedullary bone lengthening nails.Methods — We performed a systematic search in PubMed, EMBASE, and the Cochrane Library with medical subject headings: Bone Nails, Bone Lengthening, and PRECICE and FITBONE nails. Complications were graded on severity and origin.Results — The search identified 952 articles; 116 were full text screened, and 41 were included in the final analysis. 983 segments were lengthened in 782 patients (age 8–74 years). The distribution of nails was: 214 FITBONE, 747 PRECICE, 22 either FITBONE or PRECICE. Indications for lengthening were: 208 congenital shortening, 305 acquired limb shortening, 111 short stature, 158 with unidentified etiology. We identified 332 complications (34% of segments): Type I (minimal intervention) in 11% of segments; Type II (substantial change in treatment plan) in 15% of segments; Type IIIA (failure to achieve goal) in 5% of segments; and Type IIIB (new pathology or permanent sequelae) in 3% of segments. Device and bone complications were the most frequent.Interpretation — The overall risk of complications was 1 complication for every 3 segments lengthened. In 1 of every 4 segments, complications had a major impact leading to substantial change in treatment, failure to achieve lengthening goal, introduction of a new pathology, or permanent sequelae. However, as no standardized reporting method for complications exists, the true complication rates might be different.

Purpose: It is proposed that central femoral ACL graft placement better controls rotational stability. This study evaluates the consequence of changing the femoral tunnel position from the AM position drilled transtibially to the central position drilled transportally. The difference in ACL graft failure is reported. Methods: This prospective consecutive patient single surgeon study compares the revision rates of 1016 transtibial hamstring ACL reconstructions followed for 6–15 years with 464 transportal hamstring ACL reconstructions followed for 2–6 years. Sex, age, graft size, time to surgery, meniscal repair and meniscectomy data were evaluated as contributing factors for ACL graft failure to enable a multivariate analysis. To adjust for the variable follow-up a multivariate hazard ratio, failure per 100 graft years and Kaplan–Meier survivorship was determined. Results: With transtibial ACLR 52/1016 failed (5.1%). With transportal ACLR 32/464 failed (6.9%). Significant differences between transportal and transtibial ACLR were seen for graft diameter, time to surgery, medial meniscal repair rates and meniscal tissue remaining after meniscectomy. Adjusting for these the multivariate hazard ratio was 2.3 times higher in the transportal group (p = 0.001). Central tunnel placement resulted in a significantly 3.5 times higher revision rate compared to an anteromedial tunnel placement per 100 graft years (p = 0.001). Five year survival was 980/1016 (96.5%) for transtibial versus 119/131 (90.5%) for transportal. Transportal ACLR also showed a significantly higher earlier failure rate with 20/32 (61%) of the transportal failing in the first year compared with 14/52 (27%) for transtibial. (p = 0.001.) Conclusion: Transportal central femoral tunnel ACLR has a higher failure rate and earlier failure than transtibial AM femoral tunnel ACLR. Level of evidence: Level II—prospective comparative study.

Background: The aim of this study was to compare the accuracy of the oscillating tip saw system (Precision Saw = PS) with the more conventional fully oscillating blade system (Sagittal Saw = SS) during computer-assisted total knee arthroplasty (CAS-TKA).Methods: A prospective, randomised, controlled trial included 58 consecutive patients who underwent primary CAS-TKA and were randomly assigned in the PS group or the SS group to compare the accuracy of both blades. The primary outcome was the difference between the intended cutting planes and the actual cutting planes in degrees () in two planes of both the femur and the tibia. The secondary outcome was total surgery time.Results: Tibia: In the W-plane no significant differences were registered for the mean absolute deviation (p = 0.28). The PS was more accurate in the AP-plane (p = 0.03). Femur: The PS showed significantly fewer mean absolute deviations in the W-plane (p = 0.03); however, the SS revealed better accuracy in the FE-plane (p = 0.04). The difference in the surgery time between the groups was not statistically significant (p = 0.45). Two outliers were measured using the SS, while seven outliers were detected using the PS.Conclusion: The Precision Saw is not proven to be overall more accurate than the Sagittal Saw. Significantly better accuracy was shown with the PS in the two cutting planes, with the exception of one cutting plane that favoured the SS. Greater number of outliers were found using the PS. (C) 2017 Elsevier B.V. All rights reserved.

Background Due to its bone preserving philosophy, short-stem total hip arthroplasty (THA) has primarily been recommended for young and active patients. However, there may be benefits for elderly patients given a less invasive operative technique due to the short curved implant design. The purpose of this study was to compare the clinical and radiological outcomes as well as perioperative complications of a calcar-guided short stem between a young ( 75 years) population. Methods Data were collected in a total of 5 centers, and 400 short-stems were included as part of a prospective multicentre observational study between 2010 and 2014 with a mean follow-up of 49.2 months. Preoperative femur morphology was analysed using the Dorr classification. Clinical and radiological outcomes were assessed in both groups as well as perioperative complications, rates and reasons for stem revision. Results No differences were found for the mean visual analogue scale (VAS) values of rest pain, load pain, and satisfaction, whereas Harris Hip Score (HHS) was slightly better in the young group. Comparing both groups, none of the radiological parameters that were assessed (stress-shielding, cortical hypertrophy, radiolucency, osteolysis) reached differences of statistical significance. While in young patients aseptic loosening is the main cause of implant failure, in the elderly group particularly postoperative periprosthetic fractures due to accidental fall have to be considered to be of high risk. The incidence of periprosthetic fractures was found to be 0% in Dorr type A femurs, whereas in Dorr types B and C fractures occurred in 2.1 and 22.2% respectively. Conclusions Advanced age alone is not necessarily to be considered as contra-indications for calcar-guided short-stem THA, although further follow-up is needed. However, markedly reduced bone quality with femur morphology of Dorr type C seems to be associated with increased risk for postoperative periprosthetic fractures, thus indication should be limited to Dorr types A and B. Trial registration German Clinical Trials Register; DRKS00012634, 07.07.2017 (retrospectively registered).

Among the options for femoral reconstruction in total hip arthroplasty (THA) revision procedures, in cases of extensive circumferential defects, is the use of proximal femoral allografts. This technique makes it possible to correct the hip abductor mechanism and the leg length discrepancy, as well as presenting osteoconductive potential. The authors report the clinical and radiographic results from two cases of THA revision using this technique, with a minimum follow-up of 20 years.

PURPOSE: To compare anteromedial (AM) and transtibial (TT) femoral drilling hole techniques in primary anterior cruciate ligament reconstruction, using the Danish Knee Ligament Reconstruction Register, comparing revision rates and clinical outcomes from 2 time periods, 2007 to 2010 and 2012 to 2015.METHODS: A total of 8,386 primary anterior cruciate ligament reconstructions were registered between January 2007 to December 2010 and 8,818 in the period January 2012 to December 2015. Revision ACL was the primary endpoint. Secondary endpoints were the objective and subjective clinical outcomes. Crude and adjusted relative risks (RRs) with 95% confidence interval (CIs) were calculated.RESULTS: The adjusted RR for revision surgery in the AM (2007-10) group compared with the TT (2007-10) group was 1.45 (95% CI, 1.17-1.78; P < .05), but when comparing the AM (2012-15) group with TT (2012-15) group, the RR was 0.99 (95% CI, 0.68-1.45; P = .96). One-year postoperative objective stability testing showed an RR = 1.38 (95% CI, 1.19-1.60; P < .01) for rotational stability and an RR = 1.37 (95% CI, 0.99-1.89; P < .01) for sagittal stability when comparing AM (2007-10) to TT (2007-10). No significant difference in objective stability was found in the more recent period. Lastly, comparing the subjective scores, the AM (2012-15) had a significantly higher Tegner score 1 year postoperatively compared with the TT-group (2012-15).CONCLUSIONS: This study found an increased RR of revision anterior cruciate ligament and rotational and sagittal instability 1 year postoperatively for the AM technique in the period from 2007 to 2010. However, there was no significant difference in revision surgery and objective measures between the techniques from 2012 to 2015. Nevertheless, a higher activity level was found in the AM group. The results could indicate that the results found in the period 2007 to 2010 may have been caused by a learning curve when introducing a new and more complex procedure (AM).LEVEL OF EVIDENCE: Level III, retrospective comparative trial.

Place: United States

Purpose: The HemiCAP ® implant for femoral resurfacing treatment of cartilage lesions was introduced in 2003. We present outcome from a prospective cohort study of 61 patients with both trochleal and condylar lesions treated with the HemiCAP ® implant. Methods: From 2007 to 2012, 61 patients were treated with femoral resurfacing using the HemiCAP implant. There were 36 femoral condyle implants and 25 trochleal implants. Indication for treatment with HemiCAP implant was symptomatic cartilage lesion at the femoral condyle demonstrated by MRI or arthroscopy, which was ICRS grade 3–4 and size less than 4 cm 2. There were 24 males and 37 females with a median age of 49 (range 35–65) years. Patients were followed for 2 years with Knee Society subjective outcome scores (KSS), pain scores and radiographic evaluations and for 7 years with complications and reoperations. Results: At 2-year follow-up, mean KSS was improved from 52 (6.2) to 90 (7.9), mean KSS function score was improved from 45 (7.5) to 92 (8.3), and mean Pain score improved from 7.1 (0.7) to 1.8 (1.7). Twenty-three per cent of implants were revised within 7 years to arthroplasty due to progression of cartilage lesions, progression of osteoarthritis, or increased knee pain. No difference between females and males was found for reoperation rate. Conclusion: The present study demonstrated improved subjective outcome and reduced pain after femoral resurfacing using the HemiCAP implant in a relatively large cohort of patients with symptomatic cartilage lesions. A concerning 23 % reoperation rate with conversion to arthroplasty was found. Femoral resurfacing implantation treatment can be a temporary treatment for cartilage lesions expected to develop into osteoarthritis and for younger patients not eligible for arthroplasty treatment. Level of evidence: IV.

Introduction: Revision total knee arthroplasty with a cementless metaphyseal sleeve is suggested to be used without stem in revision total knee arthroplasty (rTKA). To the best of our knowledge, no papers investigating this have been published. The purpose of this study was to evaluate clinical outcome. Method: In this retrospective study, 71 patients operated with rTKA with sleeves without stem in the period 2009–2011 were identified; 63 were examined. All patients with the prosthesis still in place were invited to a medical examination including X-rays. American Knee Society Score (AKSS) and Oxford Knee Score (OKS) were used as primary clinical outcome scores. Results: Mean number of revisions including the revision with sleeve was 1.7. AKSS increased significantly from 62.7 to 109.6; (p value

Purpose: The UniCAP ® implant for femoral resurfacing treatment of large cartilage lesions and early OA was introduced in 2006. The outcome of the present study is from a prospective cohort study of 64 patients, followed 2 years clinically and 7 years for revisions. Methods: From 2009 to 2013, 64 patients were treated with femoral resurfacing using the UniCAP implant. Indication for treatment with UniCAP implant was symptomatic huge cartilage lesion or early OA at the femoral condyle demonstrated by MRI or arthroscopy, which was ICRS grades 3–4 and more than 4 cm 2. There were 28 males and 36 females with a median age of 51 (range 35–65) years. Patients were followed for 2 years clinically with Knee Society subjective outcome scores (KSS), pain scores and radiographic evaluations and for 7 years with complications and reoperations. Results: At 2 years, the follow-up mean KSS improved from 49 (6.9) to 88 (17.1), the mean KSS function score improved from 46 (8.0) to 90 (17.1), and the mean Pain score improved from 7.4 (0.5) to 2.3 (1.4). 47 % of the implants were revised within 7 years to arthroplasty due to the progression of cartilage lesions, progressing of osteoarthritis or increased knee pain. The reoperation rate did not show any significant difference between females and males. The Kaplan–Meier survival rate was 50 % at 7 years, no difference among females and males. Conclusion: The present study demonstrated an improved subjective outcome and reduced pain after femoral resurfacing using the UniCAP ® implant in a relatively large cohort of patients with symptomatic large cartilage lesions or early OA. A 47 % reoperation rate with conversion to arthroplasty was found. The femoral resurfacing implantation can be a temporary treatment for large cartilage lesions or early OA that is expected to develop into osteoarthritis. For younger patients who are ineligible for arthroplasty treatment, this implant can offer a temporary solution. Level of evidence: IV.