Surgical Techniques for Lengthening and Deformity Correction of the Femur With Lengthening Nails

Tibial and femoral osteotomies in varus deformities - radiological and clinical outcome

BACKGROUND

Varus deformities of the knee are frequently corrected by osteotomies, which should be performed at the level of origin. But in contrast to high tibial osteotomies (HTO), little data exists for distal femoral osteotomies (DFO). This study evaluates radiological and clinical outcomes after valgisation osteotomies in the proximal tibia and distal femur.

METHODS

We used an observational cohort study design and prospectively performed preoperative long standing radiographs (LSR), lateral x-rays and clinical questionnaires (SF-36, Lysholm score, VAS). Postoperative LSR and lateral x-rays were obtained on average 18 months postoperative and postoperative clinical questionnaires at final visit (mean follow up 46 months). A subgroup analysis of the different surgical techniques (oHTO vs. cDFO) was performed, with regards to radiological and clinical outcomes.

RESULTS

Finally 28 osteotomies with medial tibial opening (oHTO) or lateral femoral closing (cDFO) wedge osteotomies in 25 consecutive patients (mean age 40 years) were identified. There were 17 tibal and 11 femoral procedures. All osteotomies were performed at the origin of deformity, which was of different etiology. The average deviation of the final HKA compared to the preoperative planning was 2.4° ± 0.4°. Overall, there was a significant improvement in all clinical scores (SF-36: 61.8 to 79.4, p < 0.001; Lysholm-score: 72.7 to 90.4, p < 0.001; VAS: 3 to 1, p < 0.001). There was no significant correlation between surgical accuracy and outcome scores.

CONCLUSION

Valgisation osteotomies lead to a significant improvement in all clinical scores with the demonstrated treatment protocol. An appreciable proportion of varus deformities are of femoral origin. Since cDFO provides comparable radiological and clinical results as oHTO, this is an important treatment option for varus deformities of femoral origin.

Accuracy and Safety of Distal Femoral Valgus Correction: A Comparison of Three Techniques

Introduction

There are several methods for correcting distal femoral valgus deformity in skeletally mature patients including fixator-assisted plating (FAP), fixator-assisted nailing (FAN) and nailing using the reverse planning method. The fixator-assisted techniques have been previously compared in the literature and found to be similarly accurate. This study is the first to compare all three procedures in a single series.

Materials and methods

A retrospective review of patients who had undergone distal femoral valgus correction at a single institution between March 2017 and February 2020 was undertaken. Three different patient groups were identified based on the surgical technique used: the FAP, the FAN and the reverse planning method. The mechanical lateral distal fimoral angle (mLDFA) was recorded and compared preoperatively and postoperatively. The body mass index (BMI), duration of surgery, postoperative range of motion (ROM) and complication profile for each patient were also recorded and compared.

Results

A total of 27 limbs in 24 patients were included in this study. There were 8 male and 16 female patients. There were 10 limbs from 9 patients in the reverse planning group, 11 limbs from 11 patients in the FAN group and 6 limbs from 4 patients in the FAP group. There was a statistically significant difference in the mean preoperative and postoperative mLDFA for each of the individual groups (p < 0.0001 for each group). All patients had restoration of the mLDFA to within normal limits except one patient in the reverse planning group. This was purposefully performed to compensate for an ipsilateral proximal tibial deformity. There was no statistically significant difference in the mean preoperative and postoperative mLDFA across the groups (p = 0.2897 and 0.3440, respectively). The operative time of the reverse planning method and the FAP were significantly shorter than FAN (p = 0.0016 and p = 0.0035, respectively). The mean final knee ROM amongst the groups was similar (p = 0.8190). We recorded no infections or union complications in any group. There was one case of hardware irritation causing lateral knee pain that did not require treatment in the reverse planning group and one fracture through a temporary half-pin site in the FAN group. All six plates in the FAP group had to be removed following union on account of localised discomfort from the hardware.

Conclusion

The reverse planning method, the FAN and the FAP are comparable in terms of accuracy in achieving correction of distal femur valgus deformity in skeletally mature patients. The reverse planning method had the best combination of outcomes in this study since it was just as accurate as the FAN and the FAP techniques and did not require any additional surgeries. While both the reverse planning and the FAP were faster than the FAN technique, the reverse planning method allows the ability to perform both deformity correction and lengthening. Ultimately, the decision of which technique to use depends on a combination of the patient's preference and the surgeon's level of comfort with the technique.

How to cite this article

Iobst C, Waseemuddin M, Bafor A. Accuracy and Safety of Distal Femoral Valgus Correction: A Comparison of Three Techniques. Strategies Trauma Limb Reconstr 2020;15(1):41-46.

Complications and Effectiveness of Intramedullary Limb Lengthening: A Matched Pair Analysis of Two Different Lengthening Nails

Background

Intramedullary limb lengthening has become an accepted concept in reconstructive surgery, but as yet comparative clinical studies are missing. We compared the complications and effectiveness of two types of intramedullary limb lengthening devices (ISKD®; Fitbone®).

Materials and methods

In a retrospective series of 278 consecutive patients with internal limb lengthening, we found 17 matching pairs in terms of predefined matching parameters (group I with ISKD® and group II with Fitbone®). The surgeries were all performed with the same technique and managed with equivalent pre- and postoperative treatment protocols. The performance of the implants was evaluated using the distraction index and the weight-bearing index. Complications were rated according to Paley's classification for external lengthening.

Results

The distraction index in group I (ISKD®) was 0.99 mm/day (range 0.55-1.67) and in the group II (Fitbone®) 0.55 mm/day (range 0.14-0.92) (p value = 0.001). The mean weight-bearing index differed between group I and group II from 32.0 day/cm (range 16.4-64.0) to 51.6 day/cm (25.8-95.0) (p value = 0.001). There were 17 recorded incidents in group I and 19 in group II during lengthening.

Conclusion

Specific technical handicaps of the two systems, such as the so-called runaway of the ISKD® and backtracking of the Fitbone® nails seem to result in different distraction index and weight-bearing index. Further comparative studies might induce technical progress in intramedullary limb lengthening.

How to cite this article

Thaller PH, Frankenberg F, Degen N, et al. Complications and Effectiveness of Intramedullary Limb Lengthening: A Matched Pair Analysis of Two Different Lengthening Nails. Strategies Trauma Limb Reconstr 2020;15(1):7-12.

Deformity correction with total knee arthroplasty for severe knee osteoarthritis accompanying extra-articular femoral deformity: the results are promising

PURPOSE

This study aimed to evaluate patients with severe degenerative osteoarthritis of the knee and extra-articular femoral deformities treated with total knee arthroplasty (TKA) and acute deformity correction.

METHODS

Ten patients with severe degenerative osteoarthritis of the knee and extra-articular femoral deformities were included, and the median age was 63 years (range 38-67). The etiology was post-traumatic malunion in four patients, rickets sequelae in four patients, and surgical sequelae due to multiple epiphyseal dysplasia in two patients. The severity of degenerative osteoarthritis and deformity analyses were assessed according to the Kellgren-Lawrence and Paley criteria, respectively. The median number of previous operations the patients had undergone was two (range 0-3), and the median Oxford Knee Society score was 9 (range 5-13) before treatment. All patients were treated with primary TKA and deformity correction in the same surgery. The TKA was completed first, followed by an osteotomy at the apex of the deformity. Finally, a retrograde intramedullary nail was inserted.

RESULTS

The median follow-up period was 44 (31-60) months. A stable and functional knee joint, a physiological mechanical axis, and solid osseous union were achieved in all patients. Late prosthetic failure was seen in one patient due to deep infection. The median Oxford Knee Society score was 42 (range 37-47) at the final follow-up.

CONCLUSIONS

Combining several procedures in single setting for the treatment of severe knee osteoarthritis accompanied by extra-articular deformity may eliminate the need for multiple surgeries. Furthermore, a proper physiological mechanical axis can be obtained without causing substantial bone loss.

LEVEL OF EVIDENCE

IV.

Blocking screws for alignment control in intramedullary limb lengthening

Simultaneous deformity correction in the frontal and sagittal plane becomes more and more an important part of intramedullary lengthening to avoid further operative procedures. Such as in fracture treatment blocking screws can be used for alignment control if osteotomy is performed in the metaphyseal bone. 31 intramedullary lengthening procedures between 2009 and 2011 were retrospectively analysed for precision of simultaneous deformity correction. The average planned correction to the HKA was 2.4° (0.1°-8.0°) and the final results after lengthening deviated an average of 1.7° (0.0°-8.1°) from the planning. With blocking screws a higher degree of deformity (mean 3.2° vs. 1.7°; p<0.05) was corrected with a slightly higher precision (mean 1.5° vs. 1.9°; p=0.48) compared to patients without blocking screws. Placed on the concave side of the deformity blocking screws are a helpful tool to successfully address leg length discrepancy and other deformities with one single operation.

Use of internal lengthening nails in post-traumatic sequelae

External fixators are a well-established modality for treating fractures with bone defects, leg-length discrepancy, malunion, nonunion and other post-traumatic consequences. However, use of internal lengthening rods has remarkably increased recently for post-traumatic conditions. The main advantage of internal lengthening rods is eliminating pin-site complications. Internal lengthening rods are also associated with less pain. Motorised internal lengthening rods show promising performance in post-traumatic cases. Rigorous pre-operative planning is paramount to reducing lengthening-related complications. Certain types of internal lengthening rods offer bidirectional movement capability. Nail mechanism malfunction is a possibility with all kinds of nails. Direct doctor supervision is required, especially in the initial stages while the nail is lengthening. Internal lengthening nails are not as stiff as regular nails, with intricate internal mechanisms that can be broken under inattentive weightbearing activities. Preliminary positive outcomes indicate the role of internal lengthening rods in treating post-traumatic problems of leg-length discrepancy, malunion and nonunion.

A Concert between Biology and Biomechanics: The Influence of the Mechanical Environment on Bone Healing

In order to achieve consistent and predictable fracture healing, a broad spectrum of growth factors are required to interact with one another in a highly organized response. Critically important, the mechanical environment around the fracture site will significantly influence the way bone heals, or if it heals at all. The role of the various biological factors, the timing, and spatial relationship of their introduction, and how the mechanical environment orchestrates this activity, are all crucial aspects to consider. This review will synthesize decades of work and the acquired knowledge that has been used to develop new treatments and technologies for the regeneration and healing of bone. Moreover, it will discuss the current state of the art in experimental and clinical studies concerning the application of these mechano-biological principles to enhance bone healing, by controlling the mechanical environment under which bone regeneration takes place. This includes everything from the basic principles of fracture healing, to the influence of mechanical forces on bone regeneration, and how this knowledge has influenced current clinical practice. Finally, it will examine the efforts now being made for the integration of this research together with the findings of complementary studies in biology, tissue engineering, and regenerative medicine. By bringing together these diverse disciplines in a cohesive manner, the potential exists to enhance fracture healing and ultimately improve clinical outcomes.

Intramedullary lengthening nails: can we also correct deformities?

Unlike external fixators, the use of solid intramedullary lengthening nails is restricted to defined anatomical preconditions, such as an adequate bone length. Furthermore, all deformity corrections except the lengthening procedure have to be implemented intraoperatively and cannot be adjusted postoperatively. Conversely, even complex deformity corrections can be performed using intramedullary devices after a thorough preoperative planning. For preparation of the intramedullary cavity as well as positioning of the lengthening nail according to the preoperative planning, reaming the medullary canal with rigid reamers which don't follow the line of least resistance is inevitable. However, the application of solid lengthening nails might be limited, especially in children with ongoing epiphyseal growth, although a central perforation of the growth plate was shown to have no adverse effects on the growth potential. In cases with complex or multilevel deformities, an additional osteotomy and locking plate fixation could sometimes be a valuable solution in order to avoid external fixation. The low complication rate as well as the reduced compromising of soft tissues and periosteum render intramedullary lengthening nails the state-of-the-art procedure for limb lengthening in combination with deformity correction in patients who meet the anatomical preconditions.