Computed tomography osteoabsorptiometry alterations in stress distribution patterns through the wrist after radial shortening osteotomy for Kienböck disease

Association of dorsal malunion in distal radius fractures with wrist osteoarthritis: Alterations of bone density and stress-distribution patterns in relation to deformation angles

OBJECTIVE

Distal radius fractures (DRFs) with dorsal malunion increase the risk of osteoarthritis (OA), although the cause of post-DRF OA is yet to be elucidated. To clarify the abnormal effects of a post-DRF dorsal radius deformity, we evaluated the bone density (BD) and stress-distribution patterns of the articular surface in dorsally malunited DRFs.

DESIGN

In 36 cases of dorsally malunited DRFs following extra-articular fractures, we generated three-dimensional computerized models of the malunited distal radius from computed tomography data and extracted the subchondral bones of the radiocarpal joint (RCJ) and distal radioulnar joint (DRUJ). Both BD and stress distribution in the subchondral bones were quantitatively evaluated by comparing the affected and normal sides. Correlations of alterations in high-BD distribution and deformation angles were analyzed.

RESULTS

The center of high-BD distribution from the center of the RCJ in the volar(-)-dorsal(+) direction was dorsal (0.56 ± 0.72 mm) on the affected side compared with the normal side (-0.15 ± 0.63 mm) [95% CI: 0.43, 1.00, P < 0.0001]. The maximum stress distribution was also dorsal on the affected side (2.34 ± 3.52 mm) compared with the normal side (-2.49 ± 1.62 mm) [95% CI: 0.89, 1.79, P < 0.0001]. The alterations in BD and stress distribution correlated with the dorsiflexion and radial deviation angles. In the DRUJ, there was no significant difference in BD between the affected and normal sides.

CONCLUSIONS

In dorsally malunited DRFs, the alignment change of the RCJ resulted in high BD-concentration areas and stress distribution on the dorsal side of the radius, which may constitute a precursor for OA.

Novel Descriptions of the Radial Osteotomy in Kienböck's Disease: A Systematic Review

Purpose

Kienböck's disease consists of intrinsic and extrinsic characteristics that coalesce into a pathology with multifactorial etiology. Mechanical, morphological, and vascular factors have been identified as contributory. Radial osteotomy is one of the most commonly used surgical treatment for late-stage Kienböck's disease. Despite its frequent use and reported value, the specifics of radial osteotomy have not been described in aggregate. Our objective was to review the recent literature for descriptions of the radial osteotomy techniques used for treatment of Kienböck's disease.

Methods

The inclusion criteria for the systematic review were as follows: (1) patients aged >18 years, (2) a publication date no older than 2012, and (3) a complete description of the distal radius osteotomy technique, including verbiage that specified numeric dimensions of bony resection or verbiage that detailed a goal in terms of a radiographic parameter that would guide the bony resection.

Results

The studies were grouped according to the stated description of radial osteotomy. This process yielded the following three main groups: (1) studies that used radial shortening, (2) studies that used lateral closing wedge osteotomy or combined lateral closing wedge with radial shortening, and (3) novel osteotomy descriptions.

Conclusions

The Kienböck's disease literature predominantly describes an osteotomy to shorten the radius by 2-3 mm. In some studies, the degree of radial shortening corresponded to the value necessary to achieve near-neutral ulnar variance. The common goal in using lateral closing wedge osteotomy was to achieve a radial inclination of 5° to 15°. Unique wedge resections, some with multiplanar corrections, have been recently described with each purporting specific advantages.

Clinical relevance

Our findings support the premise of mechanical and biologic efficacy for radial osteotomy, with satisfactory results being reported across a wide spectrum of osteotomy techniques.

Effect of periacetabular osteotomy on the distribution pattern of subchondral bone mineral density in patients with hip dysplasia

Despite the availability of long-term follow-up data, the effect of pelvic osteotomy on the natural history of osteoarthritis is not yet fully understood, partly because there is untapped potential for radiographs to better describe osteoarthritis. Therefore, this study aimed to assess the distribution of subchondral bone mineral density (BMD) across the acetabulum in patients with hip dysplasia immediately (2 weeks) and 1 year after undergoing periacetabular osteotomy (PAO). To that end, we reviewed 40 hips from 33 patients with developmental dysplasia of the hip who underwent PAO between January 2016 and July 2019 at our institution. We measured subchondral BMD through the articular surface of the acetabulum using computed tomography osteoabsorptiometry, dividing the distribution map into nine segments. We then compared the subchondral BMD between 2 weeks and 1 year after PAO in each area. At 2 weeks after PAO, the high-density area tended to be localized particularly in the lateral part of the acetabulum, whereas 1 year after PAO, the high-density area moved to the central and lateral parts. The percentage ratios of the subchondral BMD for the central-posterior, lateral-central, and lateral-posterior areas relative to the central-central area were significantly decreased at 1 year after PAO, as compared to those at 2 weeks after PAO. These findings suggest that loading was altered by PAO to be more similar to physiological loading. A long follow-up observational study is warranted to confirm the association between early changes in subchondral BMD by PAO and joint degeneration.

Discrepancy in the Distribution Patterns of Subchondral Bone Density Across the Ankle Joint After Medial Opening-Wedge and Lateral Closing-Wedge High Tibial Osteotomy

BACKGROUND

High tibial osteotomy (HTO) changes the alignment and dynamics of the ankle joint; however, differences in the stress distribution of the ankle joint after opening-wedge HTO (OWHTO) and closing-wedge HTO (CWHTO) are not understood. It is believed that subchondral bone density of the articular surface reflects the pattern of cumulative stress distribution across the joint surface.

PURPOSE

To clarify the effects of OWHTO and CWHTO on the distribution patterns of subchondral bone density across the ankle joint using computed tomography (CT)-osteoabsorptiometry.

STUDY DESIGN

Cohort study; Level of evidence, 4.

METHODS

Radiographic and CT data of 18 cases who underwent OWHTO (OW group), 12 cases who underwent CWHTO (CW group), and 11 cases with unilateral anterior cruciate ligament injury serving as controls were retrospectively reviewed. The subchondral bone density of the distal tibia was assessed in the 3 groups using CT-osteoabsorptiometry. The distal tibial surface of the ankle joint was divided into 4 parts in the coronal direction, and the percentage of the high-density area (%HDA) to each subregion was compared before and after HTO.

RESULTS

Preoperatively, comparing %HDA among the 3 groups, there were no significant differences in any regions. In the OW group, postoperative %HDA in the most medial region was significantly increased compared with preoperative %HDA (49.3% to 53.0%; P = .011), and postoperative %HDA in the most lateral region was significantly decreased (21.4% to 17.2%; P = .003). On the other hand, in the CW group, postoperative %HDA in the most medial region was significantly decreased (55.7% to 35.7%; P = .001), and %HDA in the second lateral region was significantly increased (23.6% to 29.2%; P = .002).

CONCLUSION

The ankle distribution pattern of subchondral bone density shifted significantly medially after OWHTO without fibular osteotomy, whereas the distribution pattern shifted laterally after CWHTO with fibular osteotomy. When the OWHTO is performed for patients with medial ankle osteoarthritis, surgeons should pay attention to potential postoperative progression of ankle osteoarthritis due to medial shift of the stress distribution in the ankle joint.

Lunate biomechanics: application to Kienböck's disease and its treatment

Kienböck's disease was initially considered as lunate osteomalacia due to lesions of its nutrient arteries during carpal ligament tears. It has also been suggested following primary fractures, or because of repeated microtrauma. It is only in the past 20 or 30 years that it has appeared as aseptic necrosis. Based on Hultén's hypothesis that a negative radioulnar index was the cause of Kienböck's disease, equalization osteotomies (shortening of the radius or lengthening of the ulna) were developed. The observation of Kienböck's disease in subjects with a positive index and the risk of ulnar abutment after osteotomy led to the introduction of new osteotomies to get around these difficulties, still in the hope of treating the cause of Kienböck's disease. While it has been confirmed that a negative radioulnar index promotes lunate fracture, it clearly does not induce the pathology in the form of necrosis. In this scenario, perilunar osteotomies produce durable decompression, limiting the risk of lunate fracture in case of necrosis by removing the compressive constraints. After comparing the different osteotomies used to treat Kienböck's disease, it seems that the Camembert osteotomy for radius shortening, combined with selective shortening of the ulnar head as described by Sennwald, decompresses the lunate maximally, and protects it long enough for potential natural revascularization to occur.

Is There an Association Between Borderline-to-mild Dysplasia and Hip Osteoarthritis? Analysis of CT Osteoabsorptiometry

BACKGROUND

The definitive treatment of borderline-to-mild dysplasia remains controversial. A more comprehensive understanding of the etiology of osteoarthritis (OA) and clarification of any possible association between borderline-to-mild dysplasia and the pathogenesis of OA are essential.

QUESTIONS/PURPOSES

(1) Does the distribution of acetabular subchondral bone density increase according to dysplasia severity? (2) Is there an association between borderline-to-mild dysplasia and OA pathogenesis?

METHODS

We evaluated bilateral hips of patients with developmental dysplasia of the hip who underwent eccentric rotational acetabular osteotomy (ERAO) for inclusion in the dysplasia group and contralateral hips of patients with unilateral idiopathic osteonecrosis of the femoral head (ONFH) who underwent curved intertrochanteric varus osteotomy (CVO) for the control group. ERAO was performed in 46 patients and CVO was performed in 32 patients between January 2013 and August 2016 at our institution. All patients underwent bilateral hip CT. The study included 55 hips categorized according to dysplasia severity: (1) borderline-mild, 19 hips (15° ≤ lateral center-edge angle [LCEA] < 25°); (2) moderate, 20 hips (5° ≤ LCEA < 15°); (3) severe, 16 hips (LCEA < 5°); and (4) control, 15 hips. Thirty-seven dysplastic hips (age < 15 or > 50 years old, prior hip surgery, subluxation, aspherical femoral head, cam deformity, and radiographic OA) and 17 control hips (age < 15 or > 50 years old, bilateral ONFH, LCEA < 25° or ≥ 35°, cam deformity, and radiographic OA) were excluded. CT-osteoabsorptiometry (OAM) predicts physiologic biomechanical conditions in joints by evaluating subchondral bone density. We evaluated the distribution of subchondral bone densities in the acetabulum with CT-OAM, dividing the stress distribution map into six segments: anteromedial, anterolateral, centromedial, centrolateral, posteromedial, and posterolateral. We calculated the percentage of high-density area, which was defined as the upper 30% of Hounsfield units values in each region and compared least square means difference estimated by the random intercept model among the four groups.

RESULTS

In all regions, the percentage of high-density area did not differ between the borderline-mild group and the control (eg, anterolateral, 16.2 ± 5.6 [95% CI, 13.4 to 18.9] versus 15.5 ± 5.7 [95% CI, 12.4 to 18.5, p = 0.984]; centrolateral, 39.1 ± 5.7 [95% CI, 36.4 to 41.8] versus 39.5 ± 4.7 [95% CI, 36.6 to 42.5, p = 0.995]; posterolateral, 10.9 ± 5.2 [95% CI, 8.0 to 13.8] versus 15.1 ± 6.8 [95% CI, 11.7 to 18.5, p = 0.389]). In the anterolateral region, a smaller percentage of high-density area was observed in the borderline-mild group than in both the moderate group (16.2 ± 5.6 [95% CI, 13.4-18.9] versus 28.2 ± 5.1 [95% CI, 25.5-30.9], p < 0.001) and the severe group (16.2 ± 5.6 [95% CI, 13.4-18.9] versus 22.2 ± 6.8 [95% CI, 19.2-25.2, p = 0.026).

CONCLUSIONS

Our results suggest that the cumulative hip stress distribution in borderline-to-mild dysplasia was not concentrated on the lateral side of the acetabulum, unlike severe dysplasia.

CLINICAL RELEVANCE

Based on the stress distribution pattern, our results may suggest that there is no association between borderline-to-mild dysplasia and the pathogenesis of OA. Further studies are needed to evaluate the association between borderline-to-mild dysplasia and instability of the hip.

Dorsal Distraction Plating and Lunate Decortication for Stage III Kienböck Disease: A Novel Technique

Kienböck disease (KD) is a progressive condition and difficult to manage. A number of treatment algorithms exist but there is no clear consensus as to which method produces the best outcome, particularly for Lichtman stage III disease. The majority of the current treatment options for KD emphasize lunate unloading and restoration of biology with bone graft. However, less attention has been given to the protection of the lunate during revascularization process. We report a novel technique of lunate decompression and bone grafting, combined with wrist distraction with or without radial shortening osteotomy via dorsal wrist bridge plating for the treatment of stage II-IIIa/b KD. This technique provides the advantages of distraction of the carpus unloading the lunate after bone grafting and during revascularization without the issues inherent to external fixation. In addition, this technique allows compression through a radial osteotomy site when performed. Our approach to the treatment of KD has incorporated this technique for patients with stage II or IIIa/b disease.

In Vivo High-Resolution Trabecular Microstructure of Kienböck Lunate before and after Radial Shortening: A Case Report

We report a patient with stage IIIB Kienböck disease treated with radial shortening where preoperative and sequential postoperative imaging were done using in vivo high-resolution peripheral quantitative micro-computed tomography (micro-CT) scan. Sequential in vivo micro-CT scan analysis of a target zone of the Kienböck lunate of this patient demonstrated early signs of lunate remodeling (bone trabecular densification) at 5-month follow-up suggesting an ongoing healing process. These early remodeling micro-CT scan signs were confirmed at 5 years' follow-up as well.

Changes of density distribution of the subchondral bone plate after supramalleolar osteotomy for valgus ankle osteoarthritis

CT-osteoabsorptiometry (CT-OAM) has been used to visualize subchondral bone plate density distribution regarding to its mineralization. The purpose of this study was to display and analyze the density distribution of the subchondral bone plate before and after supramalleolar realignment osteotomies. We retrospectively analysed pre- and postoperative CT images of nine consecutive patients with post-traumatic unilateral valgus ankle OA. The distribution charts of CT-OAM scans were quantitatively analyzed for subchondral bone plate density distribution. VAS for pain and the Tegner activity scale were used to assess clinical outcome. At a mean follow-up of 20 ± 5.6 months (range 13-27), we observed a significant pre- to postoperative decrease of the mean high-density area ratio in tibia (lateral and posterior area) (p ≤ 0.05) and the talus (lateral area) (p ≤ 0.05). Pairwise comparison between the pre- and postoperative mineralization at the articular surface showed a significant decrease of the high-density area ratio for the tibia and the talus. The VAS decreased from 6.2 ± 0.9 pre- to 2.8 ± 0.9 postoperatively (p = 0.027), and the Tegner score inclined from 4.5 ± 1.1 preoperatively to 5.3 ± 0.7 after surgery (p = 0.082). The tibial and talar subchondral bone plate density, regarding to its mineralization, decreased after supramalleolar medial closing wedge osteotomy in patients with valgus ankle OA. The results of this study suggest that realignment surgery may decrease peak bone density areas corresponding to the alignment correction and contribute to a homogenization of the subchondral bone plate mineralization.

Long-term outcome (20 to 33 years) of radial shortening osteotomy for Kienböck's lunatomalacia

Radial shortening osteotomy (RSO) as treatment for Kienböck's disease usually improves patient symptoms for several years. Four small series have also shown that the effect may last for decades, but only two studies have used a patient-based assessment. We examined 16 patients, with a mean age at operation of 32 years, evaluating clinical and radiological results at a mean 25 (range 20 to 33) years after surgery. Three patients had progressive lunate collapse, of whom one patient needed a silicone implant arthroplasty 2 years after RSO and one patient a wrist fusion 16 years after RSO. The time between onset of symptoms and osteotomy in the remaining 14 patients averaged 20 months. The mean VAS for pain was 0.9 at rest, 0.9 with unloaded motion, 1.7 with slight, and 3.0 with heavy exertion. Two patients had marked wrist pain. Compared with the contralateral wrist the mean range of motion was 88%, grip strength was 95%, and key pinch 107%. The Disabilities of the Arm, Shoulder, and Hand score averaged 6.1, and the Mayo wrist score, 79.3. The Lichtman stage remained unchanged in 56% of patients. The inner structure of the lunate improved in all patients, and its shape remained unchanged in half of the cases. Radial shortening osteotomy provides decade-long improvement in 75% of patients and seems to be a reasonable treatment for symptomatic Kienböck's disease.

Radial shortening osteotomy for Kienböck disease: minimum 10-year follow-up

PURPOSE

To clarify long-term clinical and radiological results more than 10 years after radial shortening osteotomy for Kienböck disease.

METHODS

Eleven wrists of 10 patients that had been classified as Lichtman stages 3A (2 wrists), 3B (8 wrists), and 4 (1 wrist) underwent radial shortening for Kienböck disease. The mean follow-up period was 14.3 years (range, 10-21 y). Clinical outcomes were quantified using the Japanese version of the Disabilities of the Arm, Shoulder, and Hand questionnaire and the modified Mayo wrist score. Radiographic and magnetic resonance imaging studies were performed for 9 of the 10 patients preoperatively and all 10 patients at follow-up.

RESULTS

At follow-up, 6 wrists were asymptomatic and the remaining 5 had mild occasional pain. The mean range of extension and grip strength significantly improved. The mean modified Mayo wrist score and Disabilities of the Arm, Shoulder, and Hand scores were 92 (range, 80-100) and 5 (range, 0-18), respectively. At follow-up, no progression of the Lichtman stage was found in any patient. There was no significant progressive lunate collapse in any patient. The magnetic resonance imaging in 7 wrists showed increased signal intensity of the lunate; the remaining 3 wrists had no alteration in signal intensity of the bone.

CONCLUSIONS

Our study demonstrated satisfactory clinical results after 10 or more years in patients who underwent radial shortening for Kienböck disease. Although we found no improvement in signal intensity of the lunate in 3 wrists, unloading of the diseased lunate after radial shortening gives long-lasting symptom relief and may prevent lunate collapse.

TYPE OF STUDY/LEVEL OF DISEASE

Therapeutic IV.

STT arthrodesis versus proximal row carpectomy for Lichtman stage IIIB Kienböck's disease: first results of an ongoing observational study

INTRODUCTION

Scapho-trapezial-trapezoidal (STT) arthrodesis and proximal row carpectomy (PRC) are used for the treatment of Lichtman stage IIIB Kienböck's disease. This study prospectively compares 1-year results of STT arthrodesis and PRC in Lichtman stage IIIB Kienböck's disease.

MATERIALS AND METHODS

Nineteen patients were operated: eight with STT arthrodesis and 11 with PRC. Preoperatively and 1-year postoperatively, mobility and grip strength were examined. Both DASH and Mayo Wrist Scores were obtained from the patients.

RESULTS

In the STT arthrodesis group, mean extension/flexion worsened from 54 to 39 % of the opposite hand. Grip strength improved from 52.9 to 62.1 %. The DASH Score improved from 32.6 to 21.4, and the Mayo Wrist Score from 50.6 to 57.9. In the PRC group, extension/flexion decreased from 62.5 to 57.0 % of the opposite hand. Grip strength improved from 38.6 to 69.0 %, the DASH Score from 36.7 to 18.9, and the Mayo Wrist Score from 54.6 to 66.0.

CONCLUSION

One year after operation, slightly better results were observed in patients with PRC compared to STT arthrodesis.

Long-term stress distribution patterns of the ankle joint in varus knee alignment assessed by computed tomography osteoabsorptiometry

PURPOSE

The stress distribution of an ankle under various physiological conditions is important for long-term survival of total ankle arthroplasty. The aim of this study was to measure subchondral bone density across the distal tibial joint surface in patients with malalignment/instability of the lower limb.

METHODS

We evaluated subchondral bone density across the distal tibial joint in patients with malalignment/instability of the knee by computed tomography (CT) osteoabsorptiometry from ten ankles as controls and from 27 ankles with varus deformity/instability of the knee. The quantitative analysis focused on the location of the high-density area at the articular surface, to determine the resultant long-term stress on the ankle joint.

RESULTS

The area of maximum density of subchondral bone was located in the medial part in all subjects. The pattern of maximum density in the anterolateral area showed stepwise increases with the development of varus deformity/instability of the knee.

CONCLUSIONS

Our results should prove helpful for designing new prostheses and determining clinical indications for total ankle arthroplasty.

Distribution of bone mineral density at osteochondral donor sites in the patellofemoral joint among baseball players and controls

BACKGROUND

To theoretically minimize complications of osteochondral graft harvest from the knee, grafts should be obtained from the site of lowest stress distribution across the joint.

HYPOTHESIS

Long-term stress distribution over the patellofemoral (PF) joint surface is not equal in athletes.

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

Measurement of subchondral bone density can determine long-term resultant stress acting on an articular surface in living joints. Our analysis was performed using computed tomography (CT) image data obtained from bilateral knees of 10 college baseball fielders (fielder group) and 10 college baseball pitchers (pitcher group) and 2 control groups, including 10 college soccer players (soccer group) and 10 nonathletes (nonathlete group). The distribution pattern of subchondral bone density throughout the articular surface of the PF joint was assessed using the CT osteoabsorptiometry method. The quantitative analysis focused on the location of the low-density area at the articular surface to assess potential osteochondral donor sites.

RESULTS

All participants in the pitcher and fielder groups demonstrated a low-density area widely distributed in the proximal part of the lateral trochlea. On the other hand, a high-density area was located in the distal part of the lateral notch, of the medial notch, and of the medial trochlea. No apparent differences in the distribution pattern were found between the baseball groups and the control groups.

CONCLUSION

Our analysis, based on CT osteoabsorptiometry, indicates that the proximal lateral trochlea of the distal femur has the highest percentage area of low bone density at the PF joint level in donor knees of baseball players, soccer players, and nonathlete controls.

CLINICAL RELEVANCE

From a biomechanical viewpoint, the proximal lateral trochlea is the optimal site for harvesting osteochondral grafts in performing mosaicplasty for baseball players. This selection for the donor site may minimize postoperative PF joint symptoms.