Are dogs with hip dysplasia in less pain after total hip replacement than femoral head ostectomy?

a Knowledge Summary by

Erica R. Rehnblom DVM ^1*

Wanda J. Gordon-Evans DVM PhD DACVS DACVSMR ¹

¹University of Minnesota College of Veterinary Medicine, 1365 Gortner Ave, St Paul, MN 55108, USA
^*Corresponding Author (rehnb010@umn.edu)

Clinical scenario

You diagnosed a 1 year old female Golden Retriever with bilateral hip dysplasia and persistent hip pain despite appropriate non-surgical management. She shifts her weight forward, bunny hops and has radiographic osteoarthritis. You recommend a total hip replacement or bilateral femoral head ostectomy. The owner wants to know if one option is better at reducing the severity of long-term hip pain.

The evidence

There is only one prospective case series that directly addresses the present clinical question, however the included population size is very small. Of the literature that solely addresses total hip replacement outcome, five studies are prospective case series and five are retrospective case series. Of the literature that solely addresses femoral head ostectomy outcome, one study is a retrospective case series. There is one systematic review that addresses both total hip replacement and femoral head ostectomy, however return to normal function was their main outcome measurement rather than pain. Overall, because there is only one paper with a small population size directly addressing the present clinical question, the other included literature does not directly compare total hip replacement and femoral head ostectomy for long-term hip pain reduction, and because the current studies all use differing outcome measures and thus a direct comparison cannot be made, it is impossible to draw a meaningful conclusion as to which procedure is more efficacious at reducing long-term hip pain by comparing these studies.

THR – total hip replacement

FHO – femoral head ostectomy

LOAD questionnaire – Liverpool Osteoarthritis in Dogs questionnaire

GRF – ground reaction force

Summary of the evidence

Appraisal, application and reflection

After a thorough search of the literature, only one paper was found that specifically addresses the PICO question, and twelve papers were found that partially address it. Included in this Knowledge Summary is one systematic review, six prospective case series, and five retrospective case series. Unfortunately, other than the systematic analysis and one prospective case series with force-plate analysis and very small population size, none of the other studies directly compare THR and FHO, and differing outcome measures used throughout the studies make it difficult to draw a meaningful conclusion in regards to the clinical question.

The strongest evidence available comes from the systematic review (Bergh et al., 2014). Included in the systematic review are seven manuscripts regarding THR and one manuscript regarding FHO. In regards to the clinical question, THR consistently returned dogs to normal limb function while FHO did not consistently return dogs to normal limb function. However, it is important to note that while the systematic review represents the highest level of evidence in this study, it is not without limitations. The systematic review focused on limb functionality, which only indirectly relates to the present clinical question in regards to reducing the severity of long-term pain. It is also important to point out that the manuscripts evaluated in the systematic review used differing outcome measurements and had low levels of evidence, which means that their conclusion must be interpreted with caution.

One prospective case series (Gemmill et al., 2011) analysed 71 dogs for a total of 78 hybrid THR replacement procedures with a cementless acetabular component and a cemented femoral component with follow-up of ≥ 6 months. At time of owner outcome assessment, 75/78 (96%) of dogs were reported to have no hip pain. This subjective outcome measure of owner outcome assessment and lack of a control group weakens the evidence of this study. A second prospective case series (Budsberg et al., 1996) analysed 16 dogs for a total of 16 unilateral cemented total hip replacement procedures, 14 of which had follow-up ≥ 12 months. All dogs in this study had significantly increased GRF for loading function of the treated limb by 6 months postoperatively. Five dogs had follow-up at 24 months, and at this time all five dogs had lameness scores of 0. This study represents one of the few studies with objective outcome measurements in the form of GRF, and thus strengthens the evidence for THR reducing the severity of long-term hip pain as a result of hip dysplasia. A third prospective case series (Olmstead et al., 1983) analysed 221 THRs in 190 dogs performed predominantly as a result of hip dysplasia using physicals, radiographic examination, and owner histories in pre- and yearly post-operative patient evaluation. 136/149 (91.2%) of THRs had satisfactory function at time of follow-up suggesting that THR may reduce the severity of long-term hip pain as a result of hip dysplasia, however the subjective outcome of clinical evaluation and owner assessment weaken the evidence of this study. A fourth prospective case series (Parker et al., 1984) analysed 20 dogs with 23 THRs using a Richards Canine II large size prosthesis. Outcome evaluation consisted of direct observation and owner telephone outcome assessment. Through direct observation, THR outcome was graded using a grading system for the affected leg(s) that was adapted from Gendreau & Cawley (1977) and consisted of excellent (total weight bearing), good (slight lameness or gait abnormality), fair (noticeable lameness and may be non-weight bearing when running), and poor (severe lameness and may be non-weight bearing at all times. 18/23 (78%) of THRs had excellent or good outcome. Subjective observation and owner telephone assessment weaken the evidence that THRs provide excellent to good outcome for decreasing pain in dogs with hip dysplasia, however using a standardised grading system minimises subjective grading bias. A fifth prospective case series (Guerrero et al., 2009) anaylsed 60 dogs that underwent 65 THRs using 2^nd generation Zurich cementless THR. All dogs had post-operative evaluation which included clinical evaluation (pain on manipulation of hip joint, range of motion, muscle mass compared with contralateral leg, lameness) ≥ 6 months, and clinical evaluation was scored based on a previously reported scale, of excellent, good, fair, poor, or failed function. 60/65 (92.3%) of THRs were considered to have excellent clinical outcome. Using a standardised scale for clinical evaluation minimises subjective clinical evaluation, however the scale used was not reported, weakening the evidence supporting that THRs decrease long-term pain associated with THR. Finally, a sixth prospective case series (Dueland et al., 1977) analysed 21 dogs, 17 of which had degenerative joint disease secondary to hip dysplasia that underwent either THR and/or FHO, and four unaffected dogs as controls. Dogs were divided into four groups, group 1 was normal, unoperated dogs, group 2 was dogs with one unoperated hip vs one THR, group 3 was dogs with one THR and one FHO, and group 4 was dogs with bilateral THRs. Force-plate analysis was done to compare vertical and horizontal forces, and clinical evaluation of gait and lameness was also reported. Based on force-plate analysis, THR may functionally approach a normal hip or improve a dysplastic hip, and successful FHO may equal or surpass THR clinically and biomechanically. This study provides strong objective analysis by using force-plate technology suggesting that THR and FHO may improve gait, lameness, and force of operated limb. However, the sample size was incredibly low for each group (4–5 dogs) so a larger study should be performed before these results can be more widely accepted.

There was one retrospective case series (Bayer et al., 2019) that analysed 12 dogs for a total of 16 THR procedures using a combined implant system consisting of INNOPLANT Screw Cup, KYON taper head, and Zürich cementless (Z-THR) stem. These cases were evaluated with clinical examination and LOAD questionnaires performed by the owners. 15/16 cases had full function while 1/16 cases had acceptable function. Median LOAD score was 5 (range: 3–11). The LOAD score is a standardised tool for collecting data from owners, and in this case supported the subjective clinical examination findings and outcome determined at the final follow-up visit that THR is efficacious at reducing the severity of long-term hip pain associated with hip dysplasia. Although the retrospective and subjective outcome measures weaken the evidence of this study, this is the only retrospective case study out of five that used a standardised owner outcome questionnaire.

Of the three remaining retrospective case series regarding THR, one study (Vezzoni et al., 2015) analysed 439 Zürich cementless THR procedures and all dogs except for four had normal clinical outcome via clinical examination at their 12 month follow-up, and the remaining two studies (Massat et al., 1994; and Fitzpatrick et al., 2014) used both clinical examination and owner assessment outcome as outcome measurements, and found 84/88 cases had good or excellent outcomes, and 20/20 cases had no pain upon clinical examination respectively.

There were only three studies for FHO outcome that related to the present clinical question. The first (Rawson et al., 2005) as discussed above, found that all dogs had no hip pain at time of follow-up according to owner questionnaire. The second study (Ganesh et al., 2017) was unavailable and thus is not included in the answering of the present clinical question. The third study (Dueland et al., 1977) used force-plate analysis to determine that successful FHO may improve gait, lameness, and force of operated limb, which may be interpreted as decreased pain, however the study population was very small. Unfortunately, FHO studies are lacking, which contributes to the difficulty in answering the present clinical question. Two studies (Off & Matis et al., 2010; and Duff et al., 1977) discussing FHO outcome were not included in this Knowledge Summary due to Legg-Calvé Perthes disease being the predominant indication for surgery rather than hip dysplasia, presenting the possibility that femoral head necrosis may affect FHO outcome differently than FHO outcome due to hip dysplasia.

From the available data, it is possible that both THR and FHO may reduce the severity of long-term pain as a result of osteoarthritis secondary to hip dysplasia given the owner assessment outcomes and clinical evaluation outcomes in the aforementioned studies. However, given the differing outcome measurements between studies such as subjective non-standardised owner assessment outcomes, subjective clinical evaluation, GRF, and force-plate analysis it is impossible to compare one study to another. It is also important to mention varying postoperative pain management and physical rehabilitation not only between different studies but between individual patients in a given study as an additional variable influencing outcome and ultimately long-term pain associated with FHO and THR. It is also important to note that there are several more studies analysing THR than FHO, which provides an unequal amount of evidence towards the success of THR at reducing long-term pain associated with hip dysplasia. From the evidence, it appears that THR provides a successful outcome in many cases, however it is not evident whether THR provides a superior/inferior/or equivalent outcome compared to FHO given the lack of studies analysing FHO. In order to definitively answer the present clinical question, a prospective, randomised clinical trial, with pre-determined standardised outcome measurements, comparing THR treated dogs to FHO treated dogs with naturally occurring hip dysplasia would be necessary.

Two papers (Vezzoni et al., 2015; and Bayer et al., 2019) were not indexed by either database using the below search terms, however both papers were deemed applicable based on reference checking. This represents an inherent bias of the chosen databases, and represents a limitation of this Knowledge Summary.

Methodology Section

Search Strategy
Databases searched and dates covered:	CAB Abstracts on OVID Platform; 1973–Aug 2021 PubMed on NCBI Platform; 1972–Aug 2021
Search strategy:	CAB Abstracts: (dog or dogs or canine or canines).mp. (hip and (dysplasia or subluxation)).mp. ((total hip and (replacement or arthroplasty)) or THR or THA).mp. ((femoral head and (excision or osteotomy or ostectomy)) or excision arthroplasty or FHO).mp. 1 and 2 and (3 or 4)   PubMed: #1 dog or canine #2 hip and (dysplasia or subluxation) #3 ((total hip and (replacement or arthroplasty)) or THR or THA) #4 ((femoral head and (excision or osteotomy or ostectomy)) or excision arthroplasty or FHO) #5 #1 and #2 and (#3 or #4)   The references of relevant articles were reviewed for further relevant articles missed in the initial search.
Dates searches performed:	08 Oct 2021

Exclusion / Inclusion Criteria
Exclusion:	Book chapters, conference proceedings, articles not available in English, clinical reviews, case studies, studies with fewer than 10 dogs at time of follow-up, studies using prototypic hip replacement models, biceps femoris muscle sling technique for FHO.
Inclusion:	Articles written in English relevant to the PICO question, studies with ≥ 6 months follow-up for all included cases, studies evaluating treatment primarily for hip dysplasia (hip dysplasia as the majority of cases included in the study), commercially available total hip replacement implants.

Search Outcome
Database	Number of results	Excluded – Reviews	Excluded – Not available in English	Excluded – Not relevant to PICO question	Total relevant papers
CAB Abstracts	139	26	30	76	6
PubMed	105	14	3	80	8
Reference Checking	6	0	0	4	2
Total relevant papers when duplicates removed					12

The authors declare no conflicts of interest.

1. Bayer, K., Matiasovic, M., Steger, H. & Böttcher, P. (2019). Complications and Long-Term Outcome in 16 Canine Cementless Hybrid Hip Arthroplasties. Veterinary and Comparative Orthopaedics and Traumatology.32(1), 73–78. DOI: https://doi.org/1055/s-0038-1676072
2. Bergh, M. S. & Budsberg, S. C. (2014). A Systematic Review of the Literature Describing the Efficacy of Surgical Treatments for Canine Hip Dysplasia (1948–2012). Veterinary Surgery.43(5), 501–506. DOI: https://doi.org/10.1111/j.1532-950X.2014.12208.x
3. Budsberg, S. C., Chambers, J. N., Lue, S. L. van, Foutz, T. L. & Reece, L. (1996). Prospective evaluation of ground reaction forces in dogs undergoing unilateral total hip replacement. American Journal of Veterinary Research. 57(12), 1781–1785.
4. Dueland, R., Bartel, D. L. & Antonson, E. (1977). Force-plant technique for canine gait analysis of total hip and excision arthroplasty [proceedings]. Journal of the American Animal Hospital Association. 13(5), 547–552.
5. Duff, R. & Campbell, J. R. (1977). Long term results of excision arthroplasty of the canine hip. The Veterinary Record. 101(10), 181–184.
6. Fitzpatrick, N., Law, A. Y., Bielecki, M. & Girling, S. (2014). Cementless Total Hip Replacement in 20 Juveniles Using BFX™ Arthroplasty. Veterinary Surgery.43(6), 715–725. DOI: https://doi.org/10.1111/j.1532-950X.2014.12214.x
7. Ganesh, T. N., Siobhan Bridglalsingh & Legall, C. (2017). Femoral head and neck excision arthroplasty in 38 dogs: a two-year study with special reference to surgical indication and outcome. Indian Journal of Veterinary Surgery, 38(2), 77-80. [online] Available from: http://ovidsp.ovid.com/ovidweb.cgi?T=JS&PAGE=reference&D=caba6&NEWS=N&AN=20193238298 [Accessed 08 Aug 2021]
8. Gemmill, T. J., Pink, J., Renwick, A., Oxley, B., Downes, C., Roch, S. & McKee, W. M. (2011). Hybrid Cemented/Cementless Total Hip Replacement in Dogs: Seventy-Eight Consecutive Joint Replacements. Veterinary Surgery.40(5), 621–630. DOI: https://doi.org/10.1111/j.1532-950X.2011.00827.x
9. Guerrero, T. G. & Montavon, P. M. (2009). Zurich Cementless Total Hip Replacement: Retrospective Evaluation of 2nd Generation Implants in 60 Dogs. Veterinary Surgery.38(1), 70–80. DOI: https://doi.org/10.1111/j.1532-950X.2008.00466.x
10. Massat, B. J. & Vasseur, P. B. (1994). Clinical and radiographic results of total hip arthroplasty in dogs: 96 cases (1986–1992). Journal of the American Veterinary Medical Association. 205(3), 448–454.
11. Off, W. & Matis, U. (2010). Excision arthroplasty of the hip joint in dogs and cats. Clinical, radiographic, and gait analysis findings from the Department of Surgery, Veterinary Faculty of the Ludwig-Maximilians-University of Munich, Germany. 1997. Veterinary and Comparative Orthopaedics and Traumatology.23(5), 297–305.
12. Olmstead, M. L., Hohn, R. B. & Turner, T. M. (1983). A five-year study of 221 total hip replacements in the dog. Journal of the American Veterinary Medical Association. 183(2), 191–194.
13. Parker, R. B., Spencer, C. P., Bloomberg, M. S., Bitetto, W. & Rodkey, W. G. (1984). Canine total hip arthroplasty: a radiographic correlation of clinical results in 20 cases. Journal of the American Animal Hospital Association. 20(1), 105–113.
14. Rawson, E. A., Aronsohn, M. G. & Burk, R. L. (2005). Simultaneous Bilateral Femoral Head and Neck Ostectomy for the Treatment of Canine Hip Dysplasia. Journal of the American Animal Hospital Association. 41(3), 166–170. DOI: https://doi.org/10.5326/0410166
15. Vezzoni, L., Vezzoni, A. & Boudrieau, R. J. (2015). Long-Term Outcome of Zürich Cementless Total Hip Arthroplasty in 439 Cases. Veterinary Surgery. 44(8), 921–929. DOI: https://doi.org/10.1111/vsu.12371