Three-dimensional-printed patient-specific guides for tibial deformity correction in small-breed dogs

OBJECTIVE

To describe the use of patient-specific 3-D-printed osteotomy, reduction, and compression guides for tibial closing wedge osteotomy in small-breed dogs.

ANIMALS

6 dogs with unilateral tibial deformities.

METHODS

Six small-breed dogs with 1 or a combination of tibial deformities, including excessive tibial plateau angle, valgus, and torsion, were scheduled to undergo tibial closing wedge osteotomy using patient-specific 3-D-printed osteotomy, reduction, and compression guides. The location and orientation of the wedge osteotomy were determined based on CT data using computer-aided design software. After the tibial deformities were corrected, postoperative CT or radiographs were obtained to compare the achieved tibial limb angles with the planned angles. Clinical evaluation and radiographic follow-up were performed on all dogs.

RESULTS

Guides were successfully positioned at each specific location, and osteotomies were performed without radiation exposure or observer assistance in all dogs. Tibial deformities were corrected with angular errors of 1.8 ± 1.4°, 2.3 ± 2.1°, and 2.6 ± 1.3° in the sagittal, frontal, and transverse planes, respectively. Mild complications resolved within 1 month in 3 dogs, and revision surgery was not required. Five dogs improved to the normal gait (mean, 14.8 ± 6.6 weeks), and 1 dog recovered a satisfactory gait 24 weeks after surgery. All limbs healed 14 ± 4.7 weeks after surgery.

CLINICAL RELEVANCE

Patient-specific 3-D-printed osteotomy, reduction, and compression guides can provide effective assistance allowing accurate correction of tibial deformities. Their use yields good clinical outcomes in small-breed dogs.

Radiographic Evaluation of Isolated Continuous Compression Staples for Akin Osteotomy Fixation

Continuous compression implants (nitinol staples) are gaining popularity secondary to their lower profile, less demanding technique, and less surgical dissection. Biomechanical support exists; however, clinical data is limited in the foot/ankle. This study's purpose is to determine the efficacy of nitinol staples to achieve stable, bony healing in Akin osteotomies and examine their clinical outcomes, complications, re-operations, and pain scores. We performed a retrospective chart review on 90 patients (93 osteotomies) who underwent an Akin osteotomy using a nitinol staple over a 2-year period. Radiographs were randomized and independently reviewed by 3 blinded foot and ankle surgeons. Osteotomies were deemed healed if greater than 50% of the osteotomy contained bridging bone, partially healed as less than 50% bridging bone, and nonunion as no healing, broken hardware, or loss of reduction. Visual analog scale pain scores were analyzed. Radiographic union was seen in 98.9% of Akin osteotomies (92/93), with no loss of reduction or broken staples (0/95). Only 3.2% (3/93) of patients returned to the operating room unplanned: 1 infection (1.1%), 1 symptomatic hardware removal (1.1%), and 1 traumatic disruption of fixation (1.1%). Postoperative pain scores were significantly lower than preoperative. Staples are lower profile and technically less demanding compared to headed screws, plates, and tension band constructs. They offer continuous compression of the osteotomy and are rigid enough to maintain reduction. Based on the findings of this paper, the use of staples provides robust and stable fixation for Akin osteotomies and has low complication and high healing rates.

Two-level Osteotomy for Genu Valgum with Tibia Valga: Surgical Planning and Execution

Introduction:

Proximal tibial injury leading to tibia valga which, in turn, leading to genu valgum is well described deformity. Management options vary between growth modulation and corrective osteotomy. Osteotomy which is used for skeletally mature patients can either be done in single stage or in multiple stages or in gradual manner.

Case Report:

We describe here a method to obtain single-stage correction with two-level osteotomy in a 20-year-old patient. It includes medial closing wedge osteotomy at distal femur and translational osteotomy at tibial shaft.

Conclusion:

This method of two-level osteotomy recognizes and treats two deformities (i.e., genu valgum and tibia valga) separately and achieves correction in one stage with perfect restoration of mechanical axis of lower limb and joint line obliquity of knee.

Tibial Slope and Its Effect on Force in Anterior Cruciate Ligament Grafts: Anterior Cruciate Ligament Force Increases Linearly as Posterior Tibial Slope Increases

BACKGROUND

Previous work has reported that increased tibial slope is directly correlated with increased anterior tibial translation, possibly predisposing patients to higher rates of anterior cruciate ligament (ACL) tears and causing higher rates of ACL graft failures over the long term. However, the effect of changes in sagittal plane tibial slope on ACL reconstruction (ACLR) graft force has not been well defined.

PURPOSE/HYPOTHESIS

The purpose of this study was to quantify the effect of changes in sagittal plane tibial slope on ACLR graft force at varying knee flexion angles. Our null hypothesis was that changing the sagittal plane tibial slope would not affect force on the ACL graft.

STUDY DESIGN

Controlled laboratory study.

METHODS

Ten male fresh-frozen cadaveric knees had a posterior tibial osteotomy performed and an external fixator placed for testing and accurate slope adjustment. Following ACLR, specimens were compressed with a 200-N axial load at flexion angles of 0°, 15°, 30°, 45°, and 60°, and the graft loads were recorded through a force transducer clamped to the graft. Tibial slope was varied between -2° and 20° of posterior slope at 2° increments under these test conditions.

RESULTS

ACL graft force in the loaded testing state increased linearly as slope increased. This effect was independent of flexion angle. The final model utilized a 2-factor linear mixed-effects regression model and noted a significant, highly positive, and linear relationship between tibial slope and ACL graft force in axially loaded knees at all flexion angles tested (slope coefficient = 0.92, SE = 0.08, P < .001). Significantly higher graft force was also observed at 0° of flexion as compared with all other flexion angles for the loaded condition (all P < .001).

CONCLUSION

The authors found that tibial slope had a strong linear relationship to the amount of graft force experienced by an ACL graft in axially loaded knees. Thus, a flatter tibial slope had significantly less loading of ACL grafts, while steeper slopes increased ACL graft loading. Our biomechanical findings support recent clinical evidence of increased ACL graft failure with steeper tibial slope secondary to increased graft loading.

CLINICAL RELEVANCE

Evaluation of the effect of increasing tibial slope on ACL graft force can guide surgeons when deciding if a slope-decreasing proximal tibial osteotomy should be performed before a revision ACLR. Overall, as slope increases, ACL graft force increases, and in our study, flatter slopes had lower ACL graft forces and were protective of the ACLR graft.

Presentation and treatment of macrodactyly in children

PURPOSE

To characterize the presentation, treatment, and early outcomes of children with isolated congenital macrodactyly of the hand.

METHODS

We performed a retrospective chart review of isolated hand macrodactyly cases treated at our institution over a 15-year period. Data on clinical presentation, procedure details, and outcomes were collected.

RESULTS

A total of 21 patients, 8 boys and 13 girls, were identified. Patients had a mean of 1.8 affected digits (median, 2; range, 1-3); most (n = 12; 57%) presented with multiple affected digits. The middle finger was most commonly affected (67%). Most patients had progressive overgrowth (n = 13; 67%). Twelve patients (57%) had nerve territory-oriented macrodactyly, whereas 9 (43%) presented with lipomatous type. There were no differences between the types of macrodactyly in sex, affected side, rate of growth, digits affected, or number of procedures. Patients underwent a mean of 3.2 staged corrective operations (median, 2; range, 1-12), including soft tissue debulking (n = 19 patients; 90%), ostectomy for volume reduction or partial amputation (n = 9; 43%), closing wedge osteotomy (n = 11; 52%), epiphysiodesis (n = 7; 33%), digit transfer (n = 3; 14%), toe transfer (n = 1; 5%), and ray amputation (n = 6; 29%). Patients with progressive growth underwent more procedures than patients with static growth. No major complications were reported.

CONCLUSIONS

The diagnosis of macrodactyly should be reserved for patients with isolated congenital digit overgrowth affecting all tissue types, but clinical presentation and natural history of macrodactyly can vary greatly among patients. A variety of surgical techniques exist to reconstruct rather than amputate affected digits primarily. Although reconstruction will not result in a normal digit and requires multiple operations, our observations suggest that they are well tolerated and may offer some restored function and aesthetics. More long-term outcomes and insight into the biological basis of this disorder are needed to make better-informed treatment decisions.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic IV.

Vertebral Osteotomies in Ankylosing Spondylitis-Comparison of Outcomes Following Closing Wedge Osteotomy versus Opening Wedge Osteotomy: A Systematic Review

Study Design Systematic review. Study Rationale To seek out and assess the best quality evidence available comparing opening wedge osteotomy (OWO) and closing wedge osteotomy (CWO) in patients with ankylosing spondylitis to determine whether their results differ with regard to several different subjective and objective outcome measures. Objective The aim of this study is to determine whether there is a difference in subjective and objective outcomes when comparing CWO and OWO in patients with ankylosing spondylitis suffering from clinically significant thoracolumbar kyphosis with respect to quality-of-life assessments, complication risks, and the amount of correction of the spine achieved at follow-up. Methods A systematic review was undertaken of articles published up to July 2012. Electronic databases and reference lists of key articles were searched to identify studies comparing effectiveness and safety outcomes between adult patients with ankylosing spondylitis who received closing wedge versus opening wedge osteotomies. Studies that included pediatric patients, polysegmental osteotomies, or revision procedures were excluded. Two independent reviewers assessed the strength of evidence using the GRADE criteria and disagreements were resolved by consensus. Results From a total of 67 possible citations, 4 retrospective cohorts (class of evidence III) met our inclusion criteria and form the basis for this report. No differences in Oswestry Disability Index, visual analog scale for pain, Scoliosis Research Society (SRS)-24 score, SRS-22 score, and patient satisfaction were reported between the closing and opening wedge groups across two studies. Regarding radiological outcomes following closing versus opening osteotomies, mean change in sagittal vertical axis ranged from 8.9 to 10.8 cm and 8.0 to 10.9 cm, respectively, across three studies; mean change in lumbar lordosis ranged from 36 to 47 degrees and 19 to 41 degrees across four studies; and mean change in global kyphosis ranged from 38 to 40 degrees and 28 to 35 degrees across two studies. Across all studies, overall complication risks ranged from 0 to 16.7% following CWO and from 0 to 23.6% following OWO. Conclusion No statistically significant differences were seen in patient-reported or radiographic outcomes between CWO and OWO in any study. The risks of dural tear, neurological injury, and reoperation were similar between groups. Blood loss was greater in the closing wedge compared with the opening wedge group, while the risk of paralytic ileus was less. The overall strength of evidence for the conclusions is low.