Abstract
Objective
To assess changes in patient positioning prior to acetabular cup impaction during total hip replacement (THR) procedures in dogs.
Methods
In a prospective, analytical study, 26 client-owned dogs were evaluated for changes in patient positioning during THR procedures. Following initial patient positioning in true lateral recumbency, fluoroscopic measurement of changes in positioning was performed for each plane at 2 separate time points: after draping (M1) and immediately prior to cup impaction (M2).
Results
Patient positioning was significantly altered at time point M1 in the transverse plane, with a mean change of 2.8° (range, 0° to 12°); this change in position was most often toward the dorsum, occurring in 16 of 26 cases (62%). Significant shifting was found at time point M2 in the transverse plane, with a mean change of 2.6° (range, 0° to 10.3°); this change, however, did not significantly correlate with a particular direction. Positioning shifts found at M1 and M2 were not consistently in the same direction in either plane. Body condition score had no effect on shifting found at M1 or M2 in either plane.
Conclusions
Perfect patient positioning is not maintained with the use of bean bag positioners. Despite accurate initial positioning and the use of this positioning device, shifting does occur.
Clinical Relevance
Unrecognized shifts in pelvic position during THR procedures may occur, which could contribute to inappropriate implant positioning. Pelvic alignment should be evaluated during THR procedures to minimize the risk of complications.
Accurate patient positioning is necessary in order to minimize errors in acetabular component placement during total hip replacement (THR). This is because cup insertion reference instrumentation is designed with the assumption that the pelvis is in a perfect lateral position. Therefore, true lateral recumbency with perfect superimposition of the hemipelves is critical to the success of the procedures and is considered the ideal patient position.1 Several positioning devices are available to aid in patient positioning and, ideally, to maintain that position throughout the surgical procedure. Errors in patient positioning can occur in the transverse, dorsal, and sagittal planes, and each of these errors, if unrecognized, can lead to deviations in acetabular component position.2
Transverse plane errors can alter the surgeon’s perception of the angle of lateral opening (ALO) during implantation of the acetabular component.2,3 Of the 3 planes, patient malposition in the transverse plane is the most likely to contribute to implant placement errors3 because there are no readily accessible palpable or visible bony landmarks to evaluate position in this plane once the patient is fully draped in for surgery. Errors in ALO can lead to impingement and/or luxation.3 Over time, impingement can lead to the development of excessive wear debris and potentially aseptic loosening.1,4–6
Malpositioning in the dorsal plane can lead to errors in acetabular component version positioning (ie, anteversion, retroversion).2,7 While the cranial and caudal bone columns are useful intraoperative bony landmarks that aid in retroversion, their appearance can be obscured and/or deformed by secondary degenerative changes that are common in dogs with hip dysplasia.1,8 This can often leave these intraoperative landmarks less recognizable or unrecognizable, thus increasing the surgeon’s reliance on accurate patient positioning.
Knowledge of sagittal plane position of the pelvis may be referenced with THR surgery for the determination of the inclination of the acetabular component.2,7 This is primarily of concern for THR systems with truncation of the face of the acetabular component, most notably the BioMedtrix system.1,2,9–11 The Kyon system has a hemispherical, nontruncated cup face.1,12 The bony landmarks used to determine sagittal plane positioning (tuber sacral, plus or minus tuber coxae, and the nondependent ischiatic tuberosity) are not affected by degenerative acetabular changes. While obesity may affect the ability to palpate the tuber sacrale and tuber coxae, sagittal plane positioning of the pelvis is likely to be readily recognizable during cup impaction when using THR systems that require referencing this plane. While the sagittal plane is assessed during cup placement for some implant systems, it is not a plane of alignment that must be maintained and was not evaluated in this study.
Commercially available positioning devices include vacuum bags and positioning boards, such as the BioMedtrix positioning board (Movora; BioMedtrix) and the Kyon positioning board (Movora; Kyon) as well as the HugUVac bean bag positioners (HugUVac; Sports Doc Inc) that were used in this study. However, the ability of these devices to maintain patient position throughout the THR procedure and, in particular, up to the time of acetabular component impaction has not been evaluated in veterinary THR patients. A prior study13 evaluated this issue in human total hip arthroplasty procedures and found that positioning devices were unreliable in holding a patient’s orientation throughout these procedures. That study identified pelvic positioning changes and that pelvis malpositioning occurred when using standard positioning boards, with an average absolute value version difference of 5.3° and an absolute value inclination difference of 2.6°.13 This study13 also reported that out of 100 hips evaluated, 22% had an anteversion value altered by > 10° and another 41% altered by > 5° across the study group.
The manufacturers of the 2 most commonly used THR systems (BioMedtrix and Kyon) recommend the use of fluoroscopy during THR surgery in order to confirm appropriate patient positioning.11,12 However, the use of intraoperative fluoroscopy has not been adopted by all THR surgeons nor has the need for confirmation of patient positioning throughout the procedure been documented.
The goals of our study were to identify changes in patient positioning prior to acetabular cup impaction when using a vacuum bean bag positioner. While a previous study14 in human literature used similar methodology to that used in our study, their technique was not validated. Therefore, we performed a pilot study to ensure the precision of our measurement methodology. The outcome of interest in our study design included whether significant shifting in either the transverse or dorsal plane was seen prior to the initial skin incision following surgical limb draping (M1) and immediately prior to cup impaction (M2). Additionally, if a shift was identified, we evaluated whether the shift was more likely to occur in a particular direction in either plane. Other questions included whether measurements at M1 and M2 would consistently occur in the same or opposite directions and whether or not patient body condition score (BCS) would significantly affect position changes. Our hypotheses were that (1) the pilot study would render accurate results and would be a reliable measurement methodology for our study population, (2) patient positioning would not be significantly changed from the initial position at M1 or M2 and would not exceed > 10° in any case, (3) position changes at M1 and M2 would not be in the same direction, and (4) BCS would not affect change in position in either plane.
Methods
Pilot study
The methods utilized for the measurement of positioning errors in the transverse and dorsal planes were validated via a pilot study. The pilot study included a pelvis bone model (Sawbones) attached to an adjustable vice (Figure 1). Two inclinometers (S&F; Stead & Fast) were utilized to reference the pelvis in the transverse and dorsal planes. The first inclinometer was fixed to a line orientated with both ischiatic tuberosities to evaluate changes in the transverse plane. The second inclinometer was fixed with the tuber sacral and the ischiatic tuberosity to evaluate changes in the dorsal plane. The surgical table (Panno-med GmbH) was leveled in both the transverse and dorsal planes. Levels were also utilized to ensure 0° as a starting point for the fluoroscopy unit (OEC 9800; GE Healthcare) in the transverse and dorsal planes relative to the surgical table. The pelvis model with the mounted inclinometers was positioned such that the fluoroscopy unit was perpendicular to the long axis of the pelvis and the fluoroscopic image demonstrated acetabular superimposition when the unit’s laser was in the center of the acetabulum. The inclinometers were then zeroed. Ten separate repetitions were performed with random changes in pelvic position by manually rotating and angling the pelvis in the transverse and dorsal plane. The inclinometer’s degree of change was recorded from a starting point of zero. For each change in pelvic position, the fluoroscopy unit was rotated in the transverse and dorsal plane until superimposition of the acetabulae (with laser centered) was achieved. The change from zero on each inclinometer was compared with the corresponding change in the fluoroscopy angles.
Pilot study with inclinometers positioned in transverse and dorsal planes.
Citation: American Journal of Veterinary Research 2025; 10.2460/ajvr.24.12.0404
Clinical cases
Fluoroscopy was used to confirm initial patient position in true lateral recumbency with superimposed acetabulae. Due to the effect of magnification, if a difference in acetabular size was noted, then concentric superimposition was ensured. Patient position was reevaluated in the transverse and dorsal planes at 2 separate time points: M1 and M2. Throughout the study, both M1 and M2 measurements were calculated utilizing the same fluoroscopy unit. This was positioned in the same direction directly over the acetabulum with the laser beam centered to standardize the results as accurately as possible. This was designed as a prospective, analytical study at a single specialty referral hospital (Veterinary Care and Specialty Group, Chattanooga, TN) from April 2022 through March 2023. Cases included client-owned dogs that had a THR performed during the study period using the Kyon system. Exclusion criteria included dogs with a previous THR on the contralateral side, if a double/triple pelvic osteotomy had been previously performed, and if the integrity of the vacuum of the bean bag positioner was diminished or lost during or following the procedures.
The use of fluoroscopy and evaluation of patient positioning is a standard protocol utilized to perform THR procedures at our hospital. Therefore, owner consent was not requested during the study period because there were no changes in the surgical procedures for the purpose of this study.
Surgical technique and outcome assessment
A CBC, serum biochemistry profile, and electrolytes analysis were performed before each surgical procedure. Dogs were premedicated and anesthetized following standard protocols used by our hospital. Limb preparation included clipping and a presurgical scrub (ie, rough prep) before entering the operating room. Operating room preparation included ensuring that the operating table was level with the floor using a level placed on each side of the table. Additionally, levels were placed on the fluoroscopy unit. A HugUVac bean bag positioner was used for each case. Once the patient was in perfect lateral recumbency, the positioner was molded to the patient and vacuum was applied. Once all air was evacuated from the positioner, as evidenced by the rigidity of the positioner, the positioner was locked, and the vacuum tubing was removed. The operating table was compatible with fluoroscopy. Dogs were positioned in lateral recumbency with the surgical limb facing up and the nonsurgical limb flexed at the hip, stifle, and tarsus. The non-surgical limb was positioned next to the ventral abdomen with the use of straps passed underneath the patient to the opposite side of the table. Once lateral positioning was completed, the fluoroscopy unit was set at 0° in the transverse plane and 0° in the dorsal plane. This was then utilized to evaluate for position accuracy by ensuring superimposition of the acetabulae with the laser positioned in the center of the acetabulum. Although the iliac wing and ischium were within the image field, superimposition of these structures was not utilized due to the parallax effect. Based on evaluation during the pilot study, it was noted that if the fluoroscopy unit was not perpendicular to the long axis of the pelvis, then the rotation of the C-arm in 1 plane during the evaluation of error would affect the evaluation of the second plane. Therefore, the fluoroscopy unit was positioned at 90° to the long axis of the pelvis using a 1-m T-square. The position was evaluated fluoroscopically, and patient position was adjusted as necessary by a single board-certified surgeon (JNP) until acetabular superimposition was achieved as described in the pilot study (Figure 2). C-arm positioning and image acquisition were standardized and repeated with the same protocol for each case during the study period. The patient was held into position, and suction was applied to the positioning device to hold the patient in the defined position. Once the bean bag was secured, the device was locked, and the suction was removed. The surgical limb was hung from a standard rolling ceiling pole for aseptic preparation at an approximately 45° angle from the table (Figure 3). The limb was cut down and aseptically draped into the surgical field with the use of huck towels, patient over drape, and towel clamps. The fluoroscopy unit was repositioned as performed prior to draping. The M1 measurements were made, and the pelvis was evaluated for change in position in the transverse and dorsal planes with the laser beam centered over the acetabulum (Figure 4). No variation in the number of images or patient manipulation was performed during image acquisition. The fluoroscopy unit was rotated to recreate perfect superimposition of the acetabulae, and the degree of the transverse and dorsal changes was recorded from a single acquired image. A shift toward the dorsum (recorded as positive) or ventrum (recorded as negative) in the transverse plane and a shift toward the head (recorded as positive) or the tail (recorded as negative) in the dorsal plane were recorded. The fluoroscopy unit was set back to 0°, and the patient was repositioned to create perfect lateral alignment if shifting had occurred. The surgical procedure was started and included a standard craniolateral approach to the coxofemoral joint.15 The general order of the procedure for a Kyon THR used in this study included the following: femoral head and neck excision, femoral canal preparation, acetabular preparation, acetabular impaction, femoral stem insertion, and reduction of the prosthetic hip. Following acetabular preparation, the M2 measurements were performed immediately prior to acetabular cup impaction and in the same fashion as the M1 measurements (Figure 5). If a shift was detected, the patient was then repositioned to perfect lateral alignment as necessary before cup impaction.
Preoperative positioning and alignment confirmed with fluoroscopy (hash marks on the image correlate to the laser beam centered on the image).
Citation: American Journal of Veterinary Research 2025; 10.2460/ajvr.24.12.0404
Patient position for aseptic limb preparation. Hanging limb angle is approximately 45°.
Citation: American Journal of Veterinary Research 2025; 10.2460/ajvr.24.12.0404
Case example: evaluation after draping with a 3.7° positive shift in the transverse plane and a 0° shift in the dorsal plane.
Citation: American Journal of Veterinary Research 2025; 10.2460/ajvr.24.12.0404
Case example: evaluation prior to cup impaction with a 6.8° negative shift in the transverse plane and a 0° shift in the dorsal plane.
Citation: American Journal of Veterinary Research 2025; 10.2460/ajvr.24.12.0404
Statistical analysis
Pilot study—A paired t test was used to compare whether there was a significant difference between inclinometer and fluoroscopy measurement methods. The mean difference and SD of error difference were evaluated in both the transverse and dorsal planes. A Passing-Bablok regression was used to evaluate whether the fluoroscopic and inclinometer measurements had good agreement.
Hip study—A signed-rank test was used to test whether the absolute value of M1 and M2 (making the value agnostic to the direction of change) in the transverse and dorsal planes was significantly different from a value of zero. This was to see if the degree of change at M1 or M2 in each plane was significant. The mean and median degree changes were acquired from this test. The count and percentage of positive, negative, and zero values were computed at each measurement and plane separately to evaluate the equal probability of shifting direction using a χ2 test. A 1-sample t test was used to compare average shifting values (positive and negative) at M1 and M2 in each plane. A paired t test and a Spearman rank correlation analysis were performed with these figures to determine if an additive correlation was seen between M1 and M2 in each plane. A Pearson correlation was used to determine if BCS had a significant effect with the degree of changes found. A 1-sample Wilcoxon signed-rank test was performed according to the absolute mean and SD values at M1 and M2 in each plane to determine the case study power analysis.
Results
Pilot study
No significant differences were found in the transverse or dorsal planes between inclinometer measurements and fluoroscopy measurements. The mean difference found between the measurement modalities in the transverse plane was 0.3° (SE, 1.4953; P = .849). The mean difference found between the 2 in the dorsal plane was 0.8° (SE, 1.8979; P = .678), which indicates that the fluoroscopy readings were accurate within a degree in each plane. Regression analysis showed a gradual increase in differences in the transverse plane when higher angles (> 10°) were evaluated (with 95% CI). The analysis confirmed good agreement between both measurements in the dorsal plane (with 95% CI). The pilot study analysis concluded that the inclinometer readings and the fluoroscopy recordings were accurate and closely related.
Clinical cases
Twenty-six dogs (n = 26) were included in this study. The mean age was 36.3 months (range, 7 to 138 months), and breeds included a mixed population of mostly large- or giant-breed dogs; however, 2 mixed breeds weighing less than 14 kg were also included. The average weight was 30.5 kg (range, 11.3 to 46.5 kg), and breeds included mixed (10), German Shepherds (5), Bernese Mountain Dogs (2), Australian Shepherds (2), and 1 of each of the following: Great Pyrenees, Giant Schnauzer, Blue Tick Coonhound, Boxer, Cane Corso, American Bulldog, and Labrador Retriever. There were 11 females (10 neutered, 1 intact) and 15 males (7 neutered, 8 intact). The BCS was evaluated on a 0 to 9 scale and included dogs with a 3 (1 dog), 4 (3 dogs), 5 (17 dogs), 6 (2 dogs), and 7 (3 dogs). No cases with a BCS of 1 to 2 or 8 to 9 were in the study population. Equal side representation was found, with 13 cases having a THR performed on the left and 13 cases on the right.
Shifting of the patient position occurred in most instances; however, 5 cases had no shift at M1 or M2 in either plane. Significant shifting occurred at M1 in the transverse plane, with an absolute mean value of 2.8° (P < .001), with a range of 0° to 12°. Significant shifting also occurred at M2 in the transverse plane with an absolute mean value of 2.6° (P < .001), with a range of 0° to 10.3°. Statistically significant shifting was not seen at either M1 or M2 in the dorsal plane, and many fixed values of no shift were encountered (Table 1).
Summary statistics for position changes in both planes at M1 and M2.
| Variable | N | Mean | SD | Median | Minimum | Maximum | IQR | Signed-rank test if mean = 0 P value | Observed power for mean = 0 | Difference M2 – M1 | P value of M2 – M1 |
|---|---|---|---|---|---|---|---|---|---|---|---|
| M1 transverse | 26 | 2.8 | 3.0 | 2.2 | 0 | 12 | 4.7 | < .001 | 0.99 | 0.22 | .88 |
| M2 transverse | 26 | 2.6 | 2.8 | 2.2 | 0 | 10.3 | 4.3 | < .001 | 0.99 | ||
| M1 dorsal | 26 | 0.2 | 0.9 | 0 | 0 | 4.5 | 0 | .32 | 0.15 | 0.34 | .11 |
| M2 dorsal | 26 | 0.5 | 1.2 | 0 | 0 | 4 | 0 | .02 | 0.50 |
M1 = Measurement after draping. M2 = Measurement prior to cup impaction.
Equal probability testing identified that a positive (ie, dorsal direction) shift was more likely to occur at M1 in the transverse plane (16 of 26 cases [62%]). Trends in probability were discovered as negative (ie, ventral direction) at M2 in the transverse plane (11 of 26 cases [42%]) but were not considered statistically significant. There was not a significant predilection for either positive (ie, cranial) or negative (ie, caudal) shift/tilt in the dorsal plane. A high probability of zero values or no shift was encountered at both dorsal plane measurements (M1, 25 of 26 cases; M2, 21 of 26 cases), revealing a low power analysis for conclusion in this plane secondary to many zero values. A correlation analysis discovered significant differences between M1 and M2 in each plane, but the correlation coefficients were close to zero, indicating that values (positive or negative) typically did not occur in the same direction in either plane. Body condition score did not show a significant effect on the degree of position shifting at M1 or M2 in either plane.
Discussion
The pilot study concluded that there was agreement between inclinometer and fluoroscopy measurements within 1° in each plane; therefore, we accepted our first hypothesis. We did, however, identify a gradual worsening of difference between the fluoroscopic measurement and the inclinometer measurement in the transverse plane when higher values (ie, when malposition exceeded 10°) were recorded. The reason for error at greater deviation angle is likely due to the location of the pivot point being adjacent to the dependent hemipelvis, which results in the nondependent hemipelvis moving in more of an arc in the plane(s) of deviation. This has a minimal impact at lesser angles (< 10°), and the diminished agreement occurred beyond those typically encountered. This ensured that the methodology for case evaluation was acceptable.
Based on the results of our study, statistically significant pelvic positioning changes were found, and positioning changes at a single measurement exceeded 10°. We therefore rejected our second hypothesis. Two separate cases had a shift in the transverse plane > 10° at a single measurement, representing 7% of cases. Comparisons amongst the group identified statistically significant absolute values, with an average magnitude of positional shift of 2.8° (range, 0° to 12°) in the transverse plane at M1. We also found a higher probability that the shift would occur in the dorsal direction at M1, which occurred 62% of the time. This may have been seen secondary to hanging the surgical limb during aseptic preparation, which would have tilted the nondependent hemipelvis dorsally; however, both positive and negative values were seen at this measurement in our results. A significant positional shift of 2.6° (range, 0° to 10.3°) at M2 in the transverse plane was also found, but the probability of a specific directional shift was low and insignificant. Some of the changes found at the M2 measurement could have resulted from the external rotation and downward pressure required to access the femoral canal or from the retraction needed to expose the acetabulum.
It was not significantly likely that M1 and M2 positional changes were in the same direction for either plane; therefore, our third hypothesis was accepted. Although not statistically significant, 2 separate cases in the transverse plane had combined positional changes at M1 and M2 toward the dorsum > 10°. Additionally, a single case from this population had a maximum combined change of 16.3°, which could, if unrecognized, cause a substantial adverse effect on acetabular component positioning. Body condition score did not significantly affect change in patient position in either plane; therefore, our fourth hypothesis was also accepted. This could have been because the large majority of our study population was considered an ideal body weight, leaving only 19% of the patients with a BCS greater than 5.
The success of THR is based on many variables, and various complications have been reported in the veterinary literature.16–23 Intraoperative changes in pelvis position should be assessed as unrecognized changes in patient position could lead to complications secondary to inaccurate cup placement. Such complications include luxation and impingement. Previous publications have shown that cup placement with an inappropriate ALO or version are significant risk factors for a luxation.3,7,19,21,24,25 A previous human publication described acetabular “safe zones” of 40° ± 10° of inclination and 15° ± 10° of anteversion.26 These values have been extrapolated to veterinary medicine, and recommendations for cup placement include an ALO between 40° and 50° and retroversion of 10° to 15°.3,25,27 Findings in our study identified significant patient positioning changes in the transverse plane. These were commonly toward the dorsum, and 3 individual cases had either a single measurement or a combination of M1 and M2 values dorsally > 10°. This could contribute to cup placement with an unacceptably high ALO, increasing the risk of a dorsal luxation.3,19,21,24 Additionally, in the transverse plane, another 6 cases had a single or combined shift value between 6° and 8.3° dorsally or ventrally. Although of lesser magnitude, these changes could also contribute to cup placement with an ALO potentially out of the safe zone parameters. While the positioning changes were statistically significant, the magnitude of the mean changes was relatively small. However, 3 of 26 cases had a single or combined body positional shift > 10°, and this represented 12% of cases. It is the authors’ opinion that this frequency justifies careful confirmation of positioning prior to cup impaction.
Limitations of the current study could be attributed to several factors in the study design and the patient population evaluated. Significant values for changes in patient position were identified in the transverse plane; however, the lack of finding significant positioning changes in the dorsal plane was complicated by the frequent occurrence of no change in this plane. Perhaps a larger population size could have increased the power of our results in the dorsal plane, which would have further contributed to identifying position changes. After our M1 measurement, dogs were manually repositioned to correct any malpositioning. It is possible that, had we not corrected positioning at this time, no further change would have occurred. A separate study would be necessary to determine the total shift in patient positioning when no correction is made prior to the time of cup impaction to determine if an additive effect would be seen. The hanging leg preparation technique used in our practice likely contributed to changes in patient positioning, and other hanging leg preparation techniques may result in less patient position alteration. Our technique included surgical limb preparation with the leg hung at approximately a 45° angle and may differ from other practices. Our study did not evaluate other THR positioning devices, and these results should not be extrapolated to all positioning devices. Additionally, only a single surgeon evaluated the intraoperative imaging, which could have led to bias in evaluation. Although an experienced THR surgeon was critically assessing patient positioning, a larger assessment group may have provided different results. Our cases were selected based on presentation and included those electing THR during the study period. A wide range of degenerative changes were present in these clinical cases, and alignment with accurate visualization of the pelvis could have been more difficult or unreliable in dogs with more severe degenerative changes. Although such changes are expected in dogs presenting for THR procedures, a different population with less deformation may have yielded different values. Lastly, our results did not find any association with BCS and patient shifting. This finding is supported in another study28 that did not show statistically significant differences in initial patient positioning when comparing patients with different BCS. The results of that study concluded that BCS had no significant effect on positioning accuracy; however, our study only included a few cases with a higher BCS, and having more obese patients could have shown a different correlation with pelvic shifting.
Our study found that significant changes in patient position can occur when using vacuum bean bag positioners during THR procedures. Despite the finding of significance, it was quite uncommon for such changes to be of a magnitude that would, in the absence of additional technical errors, be expected to increase the risk of luxation or impingement. However, perfect execution of any procedure is rare, and every attempt ought to be made to minimize the risk of complications. Therefore, the authors advise careful evaluation of pelvic positioning prior to implant placement. Regardless of the accuracy of initial patient positioning, unrecognized changes in patient position could have negative consequences on THR outcomes.
Acknowledgments
None reported.
Disclosures
Dr. Peck is a paid consultant for Movora, a manufacturer of total hip replacement implants. The authors have nothing else to disclose.
No AI-assisted technologies were used in the composition of this manuscript.
Funding
The authors have nothing to disclose.
ORCID
Samuel J. Tidwell https://orcid.org/0000-0002-2204-7905
References
- 1.↑
Peck JN, Marcellin-Little DJ. Advances in Small Animal Joint Replacement. 1st ed. John Wiley & Sons Inc; 2013.
- 2.↑
Dyce J, Wisner ER, Schrader SC, Wang Q, Olmstead ML. Radiographic evaluation of acetabular component position in dogs. Vet Surg. 2001;30(1):28–39. doi:10.1053/jvet.2001.20343
- 3.↑
Dyce J, Wisner ER, Wang Q, Olmstead ML. Evaluation of risk factors for luxation after total hip replacement in dogs. Vet Surg. 2000;29(6):524–532. doi:10.1053/jvet.2000.17858
- 4.↑
El-Warrak AO, Olmstead ML, Von Rechenberg A, Auer JA. A review of aseptic loosening in total hip arthroplasty. Vet Comp Orthop Traumatol. 2001;14(3):115–124. doi:10.1055/s-0038-1632685
- 5.
Skurla CT, James SP. A comparison of canine and human UHMWPE acetabular component wear. Biomed Sci Instrum. 2001;37:245–250.
- 6.↑
Skurla CP, Pluhar GE, Frankel DJ, Egger EL, James SP. Assessing the dog as a model for human total hip replacement: analysis of 38 canine cemented femoral components retrieved at post-mortem. J Bone Joint Surg Br. 2005;87(1):120–127. doi:10.1302/0301-620X.87B1.14678
- 7.↑
Cross AR, Newell SM, Chambers JN, Shultz KB, Kubilis PS. Acetabular component orientation as an indicator of implant luxation in cemented total hip arthroplasty. Vet Surg. 2000;29(6):517–523. doi:10.1053/jvet.2000.17856
- 8.↑
Jones SC, Bula E, Dyce J. Total hip arthroplasty to address chronic hip luxation with pseudoacetabulum formation in seven dogs. Vet Surg. 2019;48(8):1530–1539. doi:10.1111/vsu.13317
- 9.↑
Renwick A, Gemmill T, Pink J, Brodbelt D, Mckee M. Radiographic evaluation of BFX acetabular component position in dogs. Vet Surg. 2011;40(5):610–620. doi:10.1111/j.1532-950X.2011.00824.x
- 10.
Dalbeth BN, Karlin WM, Lirtzman RA, Kowaleski MP. Measurement of acetabular component position in total hip arthroplasty in dogs: comparison of a radio-opaque cup position assessment device using fluoroscopy with CT assessment and direct measurement. Vet Comp Orthop Traumatol. 2020;33(5):340–347. doi:10.1055/s-0040-1714412
- 11.↑
Guit L, Gaines S, Schiller T, Rochat M. Total joint replacement. BioMedtrix Universal Hip Workshop. Movora Education: BioMedtrix; 2024. Accessed November 17 and 18, 2024. https://education.movora.com/visitor_catalog_class/show/1619462/BioMedtrix-Universal-Hip™-Workshop
- 12.↑
Miller N, Peck J. Total joint replacement. Kyon total hip replacement workshop. Movora Education: Kyon; 2024. Accessed April 21 and 22, 2024. https://education.movora.com/visitor_catalog_class/show/1371719/KYON-Total-Hip-Replacement-Workshop
- 13.↑
Milone MT, Schwarzkopf R, Meere P, Carroll KM, Jerabek SA, Vigdorchik J. Rigid patient positioning is unreliable in total hip arthroplasty. J Arthroplasty. 2017;32(6):1890–1893. doi:10.1016/j.arth.2016.12.038
- 14.↑
Lambers AP, Jennings R, Bucknill AT. A novel fluoroscopic approach to assess patient positioning in total hip arthroplasty: accuracy and the influence of body mass index. Hip Int. 2016;26(6):550–553. doi:10.5301/hipint.5000397
- 15.↑
Johnson KA. Piermattei’s Atlas of Surgical Approaches to the Bones and Joints of the Dog and Cat. 5th ed. Saunders; 2014.
- 16.↑
Bergh MS, Budsberg SC. A systematic review of the literature describing the efficacy of surgical treatments for canine hip dysplasia (1948–2012). Vet Surg. 2014;43(5):501–506. doi:10.1111/j.1532-950X.2014.12208.x
- 17.
DeYoung DJ, DeYoung BA, Aberman HA, Kenna RB, Hungerford DS. Implantation of an uncemented total hip prosthesis: technique and initial results of 100 arthroplasties. Vet Surg. 1992;21(3):168–177. doi:10.1111/j.1532-950x.1992.tb00041.x
- 18.
Olmstead ML, Hohn RB, Turner TM. A five-year study of 221 total hip replacements in the dog. J Am Vet Med Assoc. 1983;183(2):191–194. doi:10.2460/javma.1983.183.02.191
- 19.↑
Guerrero TG, Montavon PM. Zurich cementless total hip replacement: retrospective evaluation of 2nd generation implants in 60 dogs. Vet Surg. 2009;38(1):70–80. doi:10.1111/j.1532-950X.2008.00466.x
- 20.
Henderson ER, Wills A, Torrington AM, et al. Evaluation of variables influencing success and complication rates in canine total hip replacement: results from the British Veterinary Orthopaedic Association Canine Hip Registry (collation of data: 2010–2012). Vet Rec. 2017;181(1):18. doi:10.1136/vr.104036
- 21.↑
Hummel DW, Lanz OI, Werre SR. Complications of cementless total hip replacement. Vet Comp Orthop Traumatol. 2010;23(6):424–432. doi:10.3415/VCOT-09-07-0071
- 22.
Vezzoni L, Vezzoni A, Boudrieau RJ. Long-term outcome of Zürich cementless total hip arthroplasty in 439 cases. Vet Surg. 2015;44(8):921–929. doi:10.1111/vsu.12371
- 23.↑
Marcellin-Little DJ, DeYoung BA, Doyens DH, DeYoung DJ. Canine uncemented porous-coated anatomic total hip arthroplasty: results of a long-term prospective evaluation of 50 consecutive cases. Vet Surg. 1999;28(1):10–20. doi:10.1053/jvet.1999.0010
- 24.↑
Gemmill TJ, Pink J, Renwick A, et al. Hybrid cemented/cementless total hip replacement in dogs: seventy-eight consecutive joint replacements. Vet Surg. 2011;40(5):621–630. doi:10.1111/j.1532-950X.2011.00827.x
- 25.↑
Nelson LL, Dyce J, Shott S. Risk factors for ventral luxation in canine total hip replacement. Vet Surg. 2007;36(7):644–653. doi:10.1111/j.1532-950X.2007.00316.x
- 26.↑
Lewinnek GE, Lewis JL, Tarr R, Compere CL, Zimmerman JR. Dislocation after total hip replacement arthroplasties. J Bone Joint Surg. 1978;60(2):217–220.
- 27.↑
Olmstead ML. The canine cemented modular total hip prosthesis. J Am Anim Hosp Assoc. 1995;31(2):109–124. doi:10.5326/15473317-31-2-109
- 28.↑
Tidwell SJ, Barnett RJ, Marcellin-Little DJ, Peck JN. Accuracy of dog positioning before total hip replacement is high and not influenced by surgical experience. Am J Vet Res. 2025;1–7. doi:10.2460/ajvr.24.12.0401
