Complications and outcomes of total hip arthroplasty in dogs with luxoid hip dysplasia: 18 cases (2010-2022).

OBJECTIVE: To describe the complications and outcomes in dogs with luxoid hip dysplasia (LH) undergoing total hip arthroplasty (THA) and compare complication rates with THA in non-LH dogs. STUDY DESIGN: Retrospective study. SAMPLE POPULATION: Client-owned dogs (n = 217) undergoing primary THA (n = 238). METHODS: Medical records (2010-2022) of dogs undergoing THA were reviewed, and LH was defined as complete dorsal displacement of the femoral head from the acetabulum on lateral projection radiographs. Major or catastrophic complications, revisions, and outcomes were recorded for all dogs and they were compared between LH and non-LH groups. RESULTS: Eighteen cases met the subcriterion for the LH group and 220 cases met the subcriterion for inclusion in the non-LH group. There were 14 complications in 13/18 dogs with LH; seven were intraoperative (femoral fissure/fracture) and seven were postoperative (dorsal luxation, n = 5; femoral fracture, n = 1; acetabular cup septic loosening, n = 1). Revisions were performed for all LH dogs that encountered complications; satisfactory outcomes were achieved in 12/13 dogs. Overall, LH dogs had a higher risk of developing complications (p < .001), including intraoperative fracture (p < .001) and postoperative dorsal luxation (p = .019) when compared with non-LH dogs. CONCLUSION: Luxoid hip dysplasia was associated with a higher risk of major complications following THA in dogs, specifically intraoperative fissure/fracture and postoperative dorsal luxation. Despite the increased risk, revisions typically yielded satisfactory outcomes. CLINICAL SIGNIFICANCE: Luxoid hip dysplasia is an important risk factor for the development of major complications in dogs undergoing THA.

Clinical outcomes of double pelvic osteotomies in eight dogs with hip dysplasia aged 10-28 months.

OBJECTIVE: To report the short-term outcome of double pelvic osteotomy (DPO) in dogs with canine hip dysplasia ≥10 months of age. STUDY DESIGN: Case series. ANIMALS OR SAMPLE POPULATION: Eleven hips in eight dogs aged between 10 to 28 months. METHODS: Dogs clinically affected by hip dysplasia with a hip reduction angle <40°, subluxation angle <25°, dorsal acetabular rim angle between 7.5-25°, and minimal osteoarthritic changes were considered as candidates for DPO. The clinical outcome was subjectively assessed using a lameness score and pain scale upon hip extension. Norberg angle, percentage of the area of the femoral head coverage, percentage of linear femoral head coverage, pelvic width dimensions were measured on pre and postoperative radiographs. RESULTS: At the 8-week follow-up examination, all the dogs had no lameness with no pain upon hip extension. Median Norberg angle increased by 21.8% (p < .01), median percentage of the area of the femoral head coverage increased by 66.7% (p < .01) and percentage of linear femoral head coverage increased by 162.5% (p < .01) 1 year after DPO. No changes to pelvic canal width after DPO were detected. CONCLUSION: Double pelvic osteotomy improved joint congruity and clinical signs in dogs affected by hip dysplasia without osteoarthritis that were ≥10 months of age. CLINICAL SIGNIFICANCE (OR IMPACT): Double pelvic osteotomy may be a treatment option for dogs with hip dysplasia ≥10 months of age. A large study assessing long-term outcomes is indicated.

Triple pelvic osteotomy with a 12.5° and a 20° Slocum-type plate: A short-term prospective clinical pilot study in 38 dogs.

OBJECTIVE: To determine whether using 12.5° Slocum-like triple pelvic osteotomy (TPO) plates would create sufficient femoral head coverage and lower the occurrence of overrotation compared with using 20° TPO plates in dogs with hip dysplasia. STUDY DESIGN: Prospective clinical study. SAMPLE POPULATION: Thirty-five dogs with hip dysplasia (38 hips). METHODS: Nineteen hips were surgically treated with a custom-made Slocum-type 12.5° TPO plate, and these were matched to 19 hips surgically treated with a 20° commercial Slocum TPO plate. Hips were case matched according to size and breed. Ortolani sign, angles of subluxation and reduction, distraction index, and femoral head coverage (FHC) were compared between groups. Excessive coverage was defined as >80%. RESULTS: In the 12.5° group, FHC was ≥50% in all hips, with mean FHC (67%), gain (37%), and excessive coverage (11%) all significantly less than in the 20° group (79%, 54%, and 42%, respectively). CONCLUSION: The 12.5° plate produced sufficient FHC compared with the 20° plate, with fewer hips with excessive coverage. CLINICAL SIGNIFICANCE: The 12.5° TPO plate may result in sufficient FHC with a lower occurrence of excessive coverage compared with 20° plates.

Correlation of distraction index with arthroscopic findings in juvenile dogs with hip dysplasia.

OBJECTIVE: To compare distraction index (DI) with hip arthroscopy findings in juvenile dogs with hip dysplasia undergoing unilateral or bilateral double pelvic osteotomy (DPO). STUDY DESIGN: Retrospective case series. ANIMALS: Twenty dogs (36 hip joints). METHODS: Medical records from dogs undergoing unilateral or bilateral DPO (2011-2016) were reviewed. Distraction index was measured by using distraction view radiographs. Arthroscopic images were analyzed. Cartilage was graded by using the modified Outerbridge scale (0 = arthroscopically normal, 1 = chondromalacia, 2 = surface fibrillation, 3 = deep fissuring, 4 = full-thickness cartilage loss, and 5 = eburnation of exposed subchondral bone). Dorsal acetabular rim, acetabular labrum, the ligament of head of the femur, and synovitis were graded by using a four-point scale (normal, mild, moderate, severe). Spearman and Pearson correlations were used to compare DI between grade groups and age. RESULTS: Distraction index ranged from 0.4 to 1.0 (mean 0.69 ± 0.16). Most of the hips had an arthroscopically normal femoral head and acetabulum in most regions, except for the region at the insertion of the ligament of the head of the femur. There was a low positive correlation between synovitis and DI (Spearman ρ = 0.35, P = .0346). No other differences in DI were identified between grade or age groups. CONCLUSION: There was a low positive correlation between synovitis and DI. No other differences in DI were identified. CLINICAL SIGNIFICANCE: Arthroscopic evaluation of the coxofemoral joint prior to DPO can allow detection of joint pathology that might not be appreciated by using traditional radiographic screening criteria.

Total hip arthroplasty to address chronic hip luxation with pseudoacetabulum formation in seven dogs.

OBJECTIVE: To compare the outcome of dogs treated with total hip arthroplasty (THA) for chronic hip luxation and pseudoacetabulum formation to that of dogs with simple hip dysplasia and secondary osteoarthritis. STUDY DESIGN: Retrospective, case-controlled study. ANIMALS: Seven dogs with pseudoacetabulum (group 1) and 21 matched control dogs (group 2). METHODS: Each dog in group 1 was matched with three control dogs, primarily according to similarity of THA implant type and size. Patterns of radiographic pathology were characterized in each dog. Outcome measures included operative time, acetabular cup position/orientation (inclination angle, angle of lateral opening, version angle) complications, and long-term outcomes. Outcome measures were compared between groups using linear regression (P = .05). RESULTS: The presence of a pseudoacetabulum was associated with ilial remodeling and heterotopic bone formation concentric to the luxated femoral head. Exposing the native acetabulum and reducing the prosthesis were surgically challenging. The mean (SD) operative time of dogs in group 1 (96 [18] minutes) was longer than that of dogs in group 2 (63 [14] minutes; P = .00002). Cup position/orientation was not different between dogs in group 1 and group 2. One intraoperative complication and two minor postoperative complications occurred in group 1 dogs. All dogs had good long-term outcomes. CONCLUSION: Total hip arthroplasty in dogs with a pseudoacetabulum was more challenging than in control dogs. However, the procedure provided good to excellent long-term clinical outcomes in all dogs. CLINICAL SIGNIFICANCE: Surgeons should be prepared for the specific surgical challenges associated with THA in dogs with pseudoacetabulum formation.

Management of total hip replacement luxation with triple pelvic osteotomy.

OBJECTIVE: To report the outcome of dogs treated with triple pelvic osteotomy (TPO) for dorsal luxation after total hip replacement (THR). STUDY DESIGN: Retrospective clinical case series. ANIMALS: Seventeen client-owned animals. METHODS: Medical records were searched at a single institution for dogs that had been treated with TPO for dorsal THR luxation. The angle of lateral opening (ALO), version angle (VA), and inclination angle (IA) were measured from radiographs after THR and TPO and corrected for pelvic rotation. A paired t test was performed to compare cup orientation after THR and TPO. Functional outcome was assessed at follow-up examination and during telephone interviews. RESULTS: Eighteen TPOs were performed in 17 dogs, and radiographs were available for 15 cases. Open and/or closed hip reduction with additional stabilization was attempted unsuccessfully in 6 dogs prior to TPO. Triple pelvic osteotomy reduced the ALO by a mean of 23.0 ° ± 10.9 ° (P ≤ .001), increased VA by 9.0 ° ± 4.9 ° (P < .001), and increased IA by 2.9 ° ± 5.8 ° (P = .126). An excellent or good outcome was achieved in 12 dogs. Ventral luxation occurred in 3 dogs, and dorsal luxation occurred in 1 dog after TPO. Triple pelvic osteotomy excessively reduced ALO in 2 dogs with ventral luxation. CONCLUSION: Triple pelvic osteotomy with cup retention is a viable alternative to cup revision for treatment of dorsal luxation of cemented and cementless THR. Triple pelvic osteotomy significantly reduces ALO and increases VA. Careful patient selection is recommended because excessive ventroversion can lead to ventral luxation. CLINICAL SIGNIFICANCE: Triple pelvic osteotomy offers a revision option that preserves the implant-bone interface and significantly reduces ALO. This technique may be appropriate in dogs with high ALO, luxoid hips, and prior failed revision attempts.

A systematic review of the literature describing the efficacy of surgical treatments for canine hip dysplasia (1948-2012).

OBJECTIVE: To systematically evaluate the literature reporting outcome of surgical treatments for canine hip dysplasia (CHD) and to evaluate whether adequate evidence exists to support a procedure that will allow a consistent return to normal function. STUDY DESIGN: Systematic literature review. ANIMALS: Dogs with naturally occurring CHD. METHODS: An a priori question was defined and a computer-based bibliographic search was performed on PubMed, Medline, CAB Abstracts, and Veterinary Information Network through November 2012. Studies were compared and evaluated with regard to surgical technique, study design, outcome measurements, evidence classification, and evidence quality. Unilateral surgeries with >6 months postoperative follow-up were included. RESULTS: Manuscripts (n = 477) were identified and reviewed; 17 met the inclusion criteria. One study provided level I evidence, 2 provided level II evidence, 3 provided level III evidence, and 11 provided level IV evidence relative to the study question. The most common outcome measurements were orthopedic examination (70.6%), owner interview (70.6%), and visual gait observation (64.7%). Three studies used objective kinetic gait assessment. Two studies with level III evidence (total hip replacement) and 1 study with level IV evidence (juvenile pubic symphysiodesis) documented a consistent return to normal function after surgery. CONCLUSIONS: Despite a large number of publications describing clinical outcome after surgical treatments for CHD, few provided strong evidence to allow an adequate assessment of therapeutic efficacy.

Cementless total hip replacement in 20 juveniles using BFX™ arthroplasty.

OBJECTIVE: To describe outcome after a minimum of 1 year for total hip replacement (THR) using BioMedtrix BFX™ biologic fixation implants in skeletally immature dogs (6-10 months of age). STUDY DESIGN: Case series. ANIMALS: Dogs (n = 20). METHODS: Medical records (November 2007-June 2010) of 20 dogs, 6-10 months old that had cementless THR were reviewed. Preoperative, immediate, 6-week and >1-year postoperative radiographs were compared. Clinical examination was performed at 6 weeks and >1 year postoperatively. Owner questionnaire was obtained at final follow-up. RESULTS: Cementless THR using BFX™ implants was performed because of debilitating coxofemoral pain, resulting from canine hip dysplasia, after unsatisfactory outcome with medical management. Radiographs taken immediately, 6 weeks and at a mean of 29.8 months (range, 12-48 months) postoperatively revealed satisfactory implant positioning and stability. Significant change in measured cranial-caudal femoral stem fill and level (P < .001 and P = .006, respectively) were recorded at 6 weeks postoperatively without clinical significance. No further change in stem positioning occurred. Acetabular cup orientation remained unchanged throughout follow-up. Complications requiring further surgical intervention were not encountered. One minor superficial infection was recorded and treated. Lameness and pain on manipulation of the affected hip had greatly improved in all dogs by 6 weeks postoperatively. CONCLUSION: Cementless THR can safely be performed in skeletally immature dogs, providing satisfactory return to normal joint function and implant survivability for at least a mean of 29.8 months.

Surgical Technique of the 3-Dimensional-printed Personalized Hip Implant for the Treatment of Canine Hip Dysplasia.

Hip dysplasia causes major disability in dogs. Treatment options are limited to palliative treatment (e.g., pain relief, physical exercise, lifestyle changes, and weight control) or invasive surgeries such as pelvic osteotomies and total hip arthroplasty. Hence, a strong unmet need exists for an effective and dog-friendly solution that enhances the quality of life of man's best friend. We fill this treatment gap by offering a minimally traumatic and extraarticular, dog-specific, 3-dimensional-printed, hip implant (3DHIP) that restores hip joint stability. The surgical treatment using a 3DHIP implant is less invasive than osteotomies and can be performed bilaterally in one surgical session. The 3DHIP implant extends the dorsal acetabular rim of the dysplastic hip joint thereby increasing coverage of the femoral head and inhibiting joint subluxation with fast recovery. Sufficient access to the dorsal acetabular rim and ventral border of the iliac body together with optimal fitting and fixation of the implant are key steps for a successful 3DHIP implantation and imply the need for a specific approach. The present article aims to showcase this innovative surgical technique with tips and tricks as a surgical manual for implantation of the 3DHIP implant in dogs affected by hip dysplasia.

Effect of a locking triple pelvic osteotomy plate on screw loosening in 26 dogs.

OBJECTIVE: To evaluate the complication rate of the double (DPO) and triple pelvic osteotomy (TPO) procedure (unilateral and bilateral) with a locking purpose-specific plate. STUDY DESIGN: Retrospective case series ANIMALS: Dogs (n = 26; 38 hips) MATERIALS: Medical records (January 2007-January 2011) of dogs that had unilateral or bilateral DPO or TPO were evaluated. Signalment, age, body weight, estimated preoperative subluxation and reduction angles, lameness, and complications were evaluated. Follow-up radiographs were evaluated for implant loosening or failure, femoral head coverage (FCH), pelvic dimensions, and radiographic evidence of healing. RESULTS: Screw loosening occurred in 1 of 266 (0.4%) screws placed and in 1 of 38 hips (2.6%). The rate of screw loosening was significantly lower than previously reported. Only 1 hip (2.6%) developed a major complication. Minor complications involving implants occurred in 2 hips (5.3%). Three to 5 locking screws were used per plate. There was a significant increase in FCH and Norberg angle (NA) compared with preoperative values. No clinically significant change in pelvic canal dimensions measured at 3 locations was identified. CONCLUSION: Locking 7-hole TPO plates with 3-5 locking screws resulted in a lower rate of major and minor implant associated complications than the reported complication rate for conventional 6-hole plates. En bloc pullout of the caudal aspect of the plate is an infrequent but repeatable complication associated with the locking TPO implant.

String-of-pearls locking plate and cerclage wire stabilization of periprosthetic femoral fractures after total hip replacement in six dogs.

OBJECTIVE: To report use of, and outcome after, string-of-pearls (SOP™) plate and multiple cerclage wire fixation for treatment of periprosthetic femoral fractures (PFF) associated with total hip replacement (THR) in dogs. STUDY DESIGN: Case series. ANIMALS: Dogs (n=6) with PFF after THR. METHODS: Clinical records (2005-2010) and radiographic evaluations of dogs that had PFF associated with THR, treated with a SOP™ plate and cerclage wires were retrospectively reviewed. Clinical and radiographic postoperative assessments were performed 4, 12, and 24 weeks postoperatively. Telephone follow-up was performed >12 months postoperatively. RESULTS: Three fractures occurred intraoperatively and 3 occurred postoperatively. One SOP™ failed at 2 weeks necessitating revision using 2 parallel SOP™ implants. One dog was euthanatized because of quadriceps muscle tie-down at 6 weeks. Other dogs were free of lameness with full range of motion of the stifle and hip joints at final clinical examination, and positive outcomes were maintained at >12 month telephone questionnaire. There was no evidence of implant failure and positive evidence of fracture healing at final radiographic follow-up. CONCLUSIONS: Stabilization resulted in bone healing in 5 dogs; failure in 1 dog may be attributable to technical error. Optimal technical guidelines for use of the SOP™ in this circumstance are unknown, particularly where fracture configuration varies.

Use of locking plate and screws for triple pelvic osteotomy.

OBJECTIVE: To evaluate the efficacy and complication rate associated with use of a purpose-specific locking triple pelvic osteotomy (LTPO) plate. STUDY DESIGN: Prospective study. ANIMALS: Dogs (n = 9; 15 hips). METHODS: Physical examination, plain film radiography, computed tomography (CT) of the pelvis, and coxofemoral arthroscopy were performed before unilateral triple pelvic osteotomy (TPO) or staged bilateral TPO. Radiographs were taken after each procedure and 3-5, 6-8, and ≥12 weeks postoperatively. Pelvic width was measured at 3 locations to evaluate pelvic canal narrowing. RESULTS: No screw loosening occurred. Complications occurred in only 1 hip (7%) where pullout of the locking plate-screw construct from the caudal iliac segment occurred because of a fracture of the cis-cortex; the dog made a full recovery after a salvage procedure. There was no significant reduction in the cranial pelvic width but a small reduction at the level of the acetabuli and ischiatic tuberosities was noted 3-5 weeks after the 2nd TPO. CONCLUSIONS: The LTPO plate was associated with a lower complication rate than previously reported for TPOs using Slocum canine pelvic osteotomy plates (CPOP) and warrants further investigation. Pullout of the caudal plate-screw construct is a complication specific to LTPO implants. Bicortical screw purchase is recommended to prevent fracture of the cis-cortex and implant pullout.

Complications and owner assessment of canine total hip replacement: a multicenter internet based survey.

OBJECTIVE: To assess the variables associated with the complications of total hip replacement (THR) and report owner-assessed outcomes, through surgeon-based registration of cases via an online database, informed owner consent, and prospective outcomes assessment using a client-administered clinical metrology instrument. STUDY DESIGN: Prospective case series ANIMALS: Dogs (n = 170) METHODS: Entries into the British Veterinary Orthopaedic Association-Canine Hip Registry (BVOA-CHR) between January 2010 and August 2011 were reviewed. Variables evaluated included dog age, body weight, breed, and indication for THR and prosthesis. Associations between each variable and the incidence of complications were assessed using logistic regression. Additionally, an on-line, owner-administered outcomes assessment questionnaire (modified from the Liverpool Osteoarthritis in Dogs (LOAD) questionnaire) was used to collect data from owners. RESULTS: One hundred and seventy cases met the inclusion criteria. Surgical indications included hip dysplasia and coxofemoral osteoarthritis (n = 150), Legg-Calves-Perthes disease (7), coxofemoral luxation (6), fracture (4), slipped capital physis (2), and femoral head and neck ostectomy revision (1). Surgical implants were from 4 systems. The incidence of surgeon-reported complication was 9.4%. No significant association was identified between weight, age, sex, breed, indication for THR, surgical technique and prosthesis, and the incidence of complications. In 82% of the cases, owners described their satisfaction with the outcome of THR as "very good" and a total of 20% complication rate was reported. There was a statistically significant improvement in owner-assessed questionnaire score before and after THR (P < .001). CONCLUSIONS: The BVOA-CHR offers a novel framework for the prospective studies on THR and on a national/international scale. Initial complication rates from the BVOA-CHR are similar to previous studies.

Total hip replacement with dorsal acetabular rim augmentation using the SOP(TM) implant and polymethylmethacrylate cement in seven dogs with dorsal acetabular rim deficiency.

OBJECTIVE: To describe a surgical technique for reinforced augmentation of the dorsal acetabular rim (DAR) using a string-of-pearls (SOP™) locking plate and polymethylmethacrylate (PMMA) bone cement, and to report clinical outcome in 7 dogs. STUDY DESIGN: Case series. ANIMALS: Dogs (n=7). METHODS: Medical records (November 2009-April 2010) of 7 dogs with large DAR deficits, that had total hip replacement (THR) with reinforced augmentation of the DAR using a SOP™ plate and PMMA were evaluated retrospectively. Reinforced augmentation of the DAR involved anchorage of a precontoured 2.0 or 2.7 mm SOP™ plate dorsal to the acetabulum followed by application of PMMA cement to cover the reamed acetabulum and plate. Cemented acetabular components were used. Implant associated complications were recorded and ≥6-month follow-up obtained. RESULTS: In all dogs, lameness improved at medium-term reassessment (median, 8 months; range, 6-11 months). Complications included transient sciatic neurapraxia in 2 dogs, which resolved by 3 months. CONCLUSIONS: Reinforced augmentation of the DAR using a SOP™ plate and PMMA cement may facilitate placement of acetabular THR component implantation in dogs with severe DAR insufficiency.

Comparison of body weight distribution, peak vertical force, and vertical impulse as measures of hip joint pain and efficacy of total hip replacement.

OBJECTIVE: To determine whether there is a difference between the ability of peak vertical force (PVF), vertical impulse (VI), and percentage body weight distribution (%BW(dist) ) in differentiating which leg is most affected by hip joint pain before total hip replacement (THR) surgery, and for measuring changes in limb use after THR surgery. STUDY DESIGN: Prospective clinical study. ANIMALS: Dogs (n = 47). METHODS: Ground reaction force (GRF) data were collected using a pressure-sensitive walkway the day before THR surgery and at ∼3, 6, and 12 months postoperatively. PVF and VI expressed as a percentage of body weight (%PVF, %VI), and %BW(dist) were recorded. Regression models performed separately for each outcome were used for statistical analysis. RESULTS: When comparing limb use between the affected limb (AP) and the nonaffected limb (NP) preoperatively, differences between limbs were statistically significant when evaluated using PVF (P = .023), VI (P = .010), and %BW(dist) (P = .012). When evaluating the magnitude of absolute and percentage change difference in AP limb use preoperatively versus postoperatively, differences were statistically significant when evaluated using PVF (P < .001 and P = .001, respectively), VI (P = .001 and P < .001) and %BW(dist) (P < .001 and P < .001). CONCLUSION: There appeared to be no difference in the sensitivity of VI, PVF, and %BW(dist) for evaluating limb use before and after THR.

Nano total hip replacement in 12 dogs.

OBJECTIVE: To determine the short-term clinical outcome of nano total hip replacement (NanoTHR) in dogs. STUDY DESIGN: Retrospective case series. ANIMALS: Dogs (n = 12). METHODS: Medical records (2009-2011) of dogs that had nano-THR were reviewed for signalment, weight, clinical signs, side, age, prosthesis sizes, concurrent surgeries performed, complications, operative time, 3-month postoperative pelvic radiograph results, and lameness scores. RESULTS: Breeds were Yorkshire Terriers (n = 6), Toy Poodles (2), with 1 each of Maltese, Pomeranian, Cavalier King Charles Spaniel, and Shih-Tzu. Median body was 4.87 kg (range, 2.5-5.90 kg) and median age, 35.75 months (range, 12-144 months). Radiographs were taken in 4 dogs at 12 days (n = 2), 14 days (1), and 30 days (1) after surgery because of presentation for an acute grade 5 lameness. Three dogs had femoral fractures distal to the femoral implant tip and 1 dog displaced the acetabular implant medially. After revision surgery, all femoral fractures were assessed as healed with intact plate fixation. The dog with the medially displaced acetabular component responded to conservative management including strict confinement and analgesic administration. Eight dogs (58%) were assigned a grade 1 lameness and 4 dogs were grade 2 (33%) at 12-week examination. The 3 dogs with grade 5 lameness scores found to have femoral fractures within 1 month after surgery, subsequently improved to grade 1 (n = 1) and 2 (2) 12 weeks after revision surgery. The dog with medial acetabular displacement improved to a grade 2 lameness 12 weeks after conservative management. CONCLUSIONS: Although all 12 dogs had good-to-excellent outcomes, 33% experienced significant complications associated with the technique. As improvements in instrumentation and refinements in the technique are developed, NanoTHR can be considered an alternative to the femoral head and neck ostectomy (FHO) or medical management of coxofemoral disease for toy breed dogs. Further studies with a larger number of dogs and longer follow-up times are required.

Physical Rehabilitation for the Management of Canine Hip Dysplasia: 2021 Update.

Hip dysplasia is one of the most common orthopedic conditions affecting dogs. Initially, laxity of the femur leads to subluxation, and subluxation can lead to an abnormal development or to progressive degeneration of the femoral head and dorsal acetabular rim. Osteoarthritis and its clinical impact progress over time. Changes to the femoral head and neck and the acetabulum and the impact on joint motion and pain vary widely among dogs. The rehabilitation of dogs with hip dysplasia includes rehabilitation therapy in dogs managed conservatively and the rehabilitation of dogs managed with surgery.

Does the degree of preoperative subluxation or soft tissue tension affect the incidence of postoperative luxation in dogs after total hip replacement?

OBJECTIVE: To investigate whether preexisting coxofemoral subluxation/luxation predisposes to postoperative total hip replacement (THR) luxation. STUDY DESIGN: Case series. ANIMALS: Dogs (n=100) that had cemented THR (n=109); 23 normal controls. METHODS: A preliminary study was performed to validate our methods of assessing luxation and laxity by comparing dogs with severe hip dysplasia with a control population of normal dogs. For the main study, the records and radiographs of all dogs that had primary THR were reviewed. Measurements taken from preoperative radiographs to quantify hip subluxation/laxity included the Norberg angle, subluxation index, and 2 new measures: acetabular depth ratio (ADR) and dorsal acetabular rim ratio (DARR). Differences between groups that had luxation within 8 weeks and those that did not were investigated. RESULTS: Postoperative luxation occurred in 13 dogs (12%) within 8 weeks of surgery. Luxation was significantly associated with various measurements (including Norberg angle, ADR, DARR) thought to reflect degree of subluxation/soft tissue tension. CONCLUSION: Luxation after canine THR is a multifactorial problem but preexisting subluxation/soft tissue laxity is a significant risk factor for this complication.

Hybrid cemented/cementless total hip replacement in dogs: seventy-eight consecutive joint replacements.

OBJECTIVE: To evaluate the use of hybrid total hip replacement (THR), using a cementless acetabular component and a cemented femoral component. STUDY DESIGN: Prospective case series. SAMPLE POPULATION: Client-owned dogs (n = 71). MATERIALS AND METHODS: Consecutive clinical cases that had hybrid THR were studied. Radiographic features, pain scores, and lameness scores were recorded pre- and postoperatively. Longer term outcome was assessed by owner questionnaire. RESULTS: Hybrid THRs (n = 78) were performed in 71 dogs. Four cases (5%) had major postoperative complications; 3 were resolved after revision surgery, and 1 owner requested an explantation. No other major complications were identified on follow-up radiographs (67 THR) at 12 weeks. On clinical follow up (77 THR) at 4 weeks, lameness had improved in 68, was unchanged in 8, and was worse in 1. Pain had decreased in 72, was unchanged in 4, and was worse in 1. At 12 weeks (69 THR) compared with preoperative status, lameness had improved in 67 and was unchanged in 2. Pain had improved in 68 and was unchanged in 1. Longer term follow-up (mean, 16 months) was available for all hips. No further complications were reported. Owner satisfaction was good for 76 THRs and reasonable for 2. CONCLUSIONS: Hybrid THR can be performed successfully with a low complication rate and represents an alternative to either entirely cemented or cementless implantation.

Juvenile pubic symphysiodesis and juvenile pubic symphysiodesis associated with pectineus myotomy: short-term outcome in 56 dysplastic puppies.

OBJECTIVES: (1) To compare short-term outcome of juvenile pubic symphysiodesis (JPS) in puppies aged 12-17 weeks with lax hips (group JPS1), in puppies aged 18-22 weeks (group JPS2), and control (group C) puppies; and (2) to document outcome of bilateral pectineus myotomy (PM) associated with JPS in 18-22-week-old puppies (group JPS-PM). STUDY DESIGN: Prospective study. METHODS: Puppies (12-22 weeks) from large and giant breed dogs with a combination of a positive Ortolani sign, poor acetabular coverage (Norberg angle [NA]0.5 for one or both hips were selected. Puppies aged <18 weeks were randomly assigned to group JPS1 or C. Puppies aged 18-22 weeks were randomly assigned to group JPS2, JPS-PM, or C. Three to 4 months later, surgery was considered successful in pain-free dogs with negative Ortolani sign, normalized acetabular coverage (NA>or=105 degrees ), and SI>0.5. Success rates were compared using Fisher's exact tests: JPS1 versus JPS2 versus C; JPS2 versus JPS-PM. Significance was set at P<.05. RESULTS: All dysplastic hips from nonoperated (C) groups were dysplastic at follow-up, meaning that our criteria for case selection were accurate. JPS1 had significantly better success rate than JPS2 (85 versus 17.8%, respectively). JPS-PM dysplastic hips failed to demonstrate a better outcome than JPS2 hips. CLINICAL RELEVANCE: This study confirms, on a large series of dysplastic hips, the age-dependent effects of JPS, with better results if performed before 18 weeks of age. There is no benefit of adding PM to the procedure in candidates >18 weeks at surgery.