Complications and Long-Term Outcomes After Prosthetic Capsule Replacement in 15 Dogs with Traumatic Hip Luxation
ABSTRACT
Complications and long-term clinical outcomes for 15 dogs surgically treated for traumatic craniodorsal hip luxation by prosthetic capsule replacement (PCR) with a prosthetic ligament were retrospectively reviewed. A PCR technique with capsulorrhaphy was performed in all dogs using acetabular screws with washers and a femoral tunnel as anchor points for the polyester prosthetic ligament. A non–weight-bearing sling was not placed. Minimum 1 yr follow-up period was required for study inclusion. Two major complications (13.3%) consisting of craniodorsal hip reluxation (n = 1) and capital physeal fracture (n = 1) were observed. Minor complications (superficial skin necrosis) occurred in one case (6.7 %). The patient with craniodorsal hip reluxation underwent femoral head and neck ostectomy and was excluded from long-term analysis. In the 11 cases that returned for long-term (median, 3.8 yr; range, 19–75 mo) evaluation at the authors’ institution, 10/11 of the dogs were clinically sound. Three dogs did not return for long-term evaluation. However, telephone interview with owners minimum1 yr after surgery indicated normal limb function and absence of complications in all three cases. These results suggest that PCR with polyester prosthetic ligament can be successful in maintaining hip reduction in dogs with craniodorsal hip luxation.
Introduction
Traumatic hip luxation is a common injury in mature dogs that typically occurs in a craniodorsal direction owing to the significant pull of the gluteal and iliopsoas muscles.1,2
Surgical and nonsurgical methods for treating hip luxation have been reported. Closed reduction with non–weight-bearing sling stabilization has been associated with high reluxation rates (15–71%).3,4 Surgical treatments can be divided into intra- and extraarticular techniques. All of these techniques include a common mechanism for maintaining joint stability until the soft tissues have healed with maturation of scar tissue and reformation of the joint capsule.5,6 Intraarticular repairs include transarticular pinning and toggle rod stabilization. Although these procedures are described with good outcomes, the use of intraarticular implants may further damage the articular surface, encouraging the progression of degenerative joint disease.2,4,6–9 Extraarticular techniques include iliofemoral suture, prosthetic capsule replacement (PCR), greater trochanteric transposition, sacrotuberous ligament transposition, ischioilial pinning, deep gluteal muscle tenodesis, triple pelvic osteotomy, and external skeletal fixation.4,10–15
Prosthetic capsule replacement uses bone screws with washers, bone anchors, or bone tunnels as anchor points for large prosthetic absorbable or nonabsorbable suture material.13–15 Three reports have documented clinical outcomes of PCR used for treatment of craniodorsal hip luxation (CHL) in dogs with successful outcomes in 65–67% of cases.13–15 These studies differ substantially in both surgical technique and suture material used. Allen et al. first described a PCR technique with the placement of two bone screws with washers in the dorsal acetabular rim and a bone tunnel drilled through the femoral neck just lateral and distal to the joint capsule attachment.13 Johnson et al. and Braden et al. modified the original technique with the addition of a third screw and washer in the trochanteric fossa of the femur.14,15 In these three studies, a dorsal approach to the hip with osteotomy and transposition of the greater trochanter was performed and an additional postoperative non–weight-bearing sling was used in most dogs for 7–10 days.13–15
The objectives of this study were to describe a modification of the original Allen surgical technique, that did not use a greater trochanteric osteotomy or a non–weight-bearing sling, in dogs with traumatic CHL and to report long-term clinical and radiographic outcomes.
Materials and Methods
Case Selection Criteria
The medical records database of Centre Hospitalier Vétérinaire Anicura-Aquivet were searched to identify dogs that underwent a PCR for treatment of traumatic CHL between January 1, 2015, and July 31, 2019. Dogs were included in the study if preoperative, immediate postoperative, and follow-up radiographs were available for review and a recheck examination was performed by the primary surgeon 4–10 wk postoperatively. Data were collected a minimum of 1 yr from the time of surgery in order to achieve long-term follow-up. Dogs with nontraumatic CHL, luxation direction other than craniodorsal, and concomitant fracture of the femoral head were excluded. Informed consent was obtained from the pet owners. All patients were clinically managed according to contemporary standards of care.
Medical Records Review
Data obtained from the medical records included signalment, intended function of the dog, cause of CHL, limb affected, duration of luxation before surgical intervention, previous treatment for CHL, and other concurrent injuries or orthopedic diseases. Lameness score (preoperative and recheck), radiographic findings, surgical approach, type of implants used for PCR, postoperative complications, and duration of follow-up were also recorded. Lameness was scored on a numerical rating scale from 0 to 5, as previously described: 0 (clinically sound), 1 (barely detectable), 2 (mild), 3 (moderate), 4 (severe), and 5 (non–weight-bearing).16
Preoperative Diagnostic Imaging
Preoperative radiographs included mediolateral and craniocaudal views of the femur as well as a ventrodorsal extended hip view. Images were reviewed by the primary surgeon for evidence of pathological changes, including femoral head fracture, abnormal femoral head conformation, femoral head subluxation, abnormal acetabular cup conformation, osteophytosis, and soft tissue calcification.
Stabilization Technique
Preanesthetic blood tests were performed dependent on the patient’s signalment and comorbidities. If needed, medical stabilization was performed before surgery. Dogs were anesthetized for surgery according to standard protocols used in our clinic. Analgesia was provided with morphinea (0.2 mg/kg IV). Amoxicillin-clavulanic acidb or cefazolinc was administered 30 min before skin incision and every 90 min throughout the surgery. All procedures were performed by the same board-certified surgeon (J.G.G.).
Following standard aseptic preparation, dogs were placed in lateral recumbency. The surgical field was further protected with a sterile, adhesive, clear plastic incision drape. A craniolateral approach to the hip was performed as described by Archibald et al.17 The remnants of the round ligament were excised with a #11 scalpel blade. The femoral head was inspected for cartilaginous lesions. Fibrin, blood clots, granulation tissue, and any fibrous tissues identified were removed from the acetabular cup. A modification of the original PCR technique described by Allen et al. was used.13 A bone tunnel was drilled from cranial to caudal into the proximal portion of the femoral neck along the joint capsule insertion. The bone tunnel size was 2.0 mm in diameter. One strand of 3 or 6 USP synthetic coated polyester suture materiald was passed through the tunnel. The luxation was reduced, and the joint capsule remnants were closed with an interrupted cruciate pattern using polydioxanonee. When capsular damage was extensive, adjacent soft tissues (i.e., rectus femoris and vastus lateralis muscles) were incorporated in the capsular sutures to ensure sufficient joint coverage.
Bicortical screws with spiked washers were used as anchor points for the suture material. Two bone screws were typically placed in the dorsal acetabular rim. Only one screw was used in cases with capsular tears confined to the cranial aspect of the joint capsule (n = 2). The caudal screw was first placed approximately at the level of the dorsal midline of the rim. The cranial screw was half the distance between the rectus femoris origin and the caudal screw or at a point slightly more cranial to accommodate the diameters of the two washers and avoid interference between them (Figure 1). Screw diameters (between 2.7 mm and 3.5 mm) were selected at the discretion of the surgeon. Screws were directed medially to avoid damage to the articular cartilage. Screws and washers were placed but not fully tightened. The cranial strand of the femoral suture was passed around the caudal screw. The remaining caudal strand was passed around the cranial screw. Both ends were tightened together and secured with a five-throw surgeon’s knot while the limb was held in slight abduction and internal rotation. The screws were then fully tightened to prevent prosthetic slippage. No tensioning device was used. Range of motion was assessed in the operating room, and successful stabilization of the hip was confirmed by manipulating the joint in adduction, abduction, external and internal rotation, and rotary planes. The surgical approach was closed routinely. Postoperative orthogonal radiographs were obtained before recovery from anesthesia to assess joint congruity and implant placement.
Citation: Journal of the American Animal Hospital Association 59, 2; 10.5326/JAAHA-MS-7244
Postoperative Care
No additional external coaptation was used. Morphine (0.2 mg/kg, IV, q 4 hr) was administered for analgesia during hospitalization. Patients were discharged from the hospital 1–2 days after surgery with anti-inflammatory (meloxicamf [0.1 mg/kg per os (PO) q 24 hr for 7 days]) and antimicrobial medications (amoxicillin-clavulanic acidg [20 mg/kg PO q 12 hr] or cefalexineh [15–25 mg/kg PO q 12 hr] for 5 days). Dogs were confined to a small room or cage. Short leash walks 3–4 times daily with an abdominal sling was the only recommended activity during the initial 4–10 wk after surgery until clinical and radiographic recheck. Activities were gradually introduced over 1 mo after the first recheck barring any complications or setbacks. After 10 wk, unrestricted activities were allowed.
Outcome Assessment
The patients were reexamined at the authors’ institution by the primary surgeon 4–10 wk postoperatively for clinical and radiographic recheck (short-term follow-up). Owners were instructed to return for rechecks 6 wk postoperatively, but some owners scheduled appointments earlier or later than desired. Lameness was scored using the aforementioned grading system. Pain, crepitus, instability, and range of motion on manipulation of the hip were documented. The authors reviewed immediate postoperative and follow-up radiographs for assessment of joint congruency and evidence of implant migration and, in follow-up radiographs, the development of hip osteoarthritis. Complications were reported as previously defined by Cook et al. as catastrophic, major, or minor.18 Time from surgery to complication was recorded, and, if more than one complication occurred in one patient, each was considered as a separate data point.
The primary surgeon performed long-term clinical rechecks at the authors’ institution a minimum of 12 mo postoperatively. Not all dogs were reexamined, as some dogs did not return for long-term follow-up. Eleven of the 15 dogs (73.3%) returned for the long-term follow-up and were reexamined by the primary surgeon. Lameness was subjectively graded again as previously described. Hip crepitus, pain, range of motion, and stability during manipulation were recorded. At the time of recheck, radiographs were recommended to the owners but not required. Radiographic evaluations were proposed for assessment of long-term joint congruency, evidence of implant migration, and development of hip osteoarthritis. All owners of dogs returning for long-term follow-up (n = 11) elected to pursue radiographs. On this occasion, the owners were asked to subjectively grade the outcome of their dog as “full,” “acceptable,” or “unacceptable.”18 The surgeon used a combination of clinical and radiographic assessment (in the 11 cases that returned for long-term follow-up), in addition to owner assessment, to determine the level of sporting performance or return to previous activity permitted. Telephone consultation using a modified owner-answered telephone questionnaire (Appendix 1) was carried out in the three cases that did not return for long-term evaluation.19
Data Analysis
Data were entered into a spreadsheeti. Descriptive statistics were calculated, with median and range reported. Data frequencies in each category were reported.
Results
Fifteen dogs met the inclusion criteria (Table 1). Median age was 3 yr (range, 0.17–7) and median body weight was 22.4 kg (range, 6.1–68). The primary uses or activities of dogs included companion (n = 8), agility (n = 2), defense (n = 2), and hunting (n = 3). Road traffic accident was the cause of CHL in 10 cases. The remaining 5 cases were due to domestic accident (n = 2), unknown trauma (n = 2), and hunting accident (n = 1). Seven dogs presented with a left-sided hip luxation and 8 dogs presented with a right-sided hip luxation. Concomitant orthopedic injuries were found in 3 dogs and included ipsilateral femoral fractures (n = 2), contralateral femoral fracture (n = 1), and bilateral pelvic/ischiatic fractures (n = 1). Case 5 presented with an ipsilateral comminuted diaphyseal femoral fracture that was treated with open reduction and internal fixation using a bone plate and screws, as well as a contralateral capital physeal fracture that was left untreated because of owner financial constraints. Case 9 presented with an ipsilateral simple transverse diaphyseal femoral fracture that was treated with open reduction and internal fixation using a bone plate and screws. Case 1 presented with bilateral ischiatic and pubic fractures and was treated conservatively. Fourteen of 15 cases were non–weight-bearing on admission. Case 15 demonstrated grade 3/5 lameness in the limb with CHL. Two cases had moderate to severe hip dysplasia and osteoarthritis at the time of surgery. The surgeon initially performed closed reduction under general anesthesia in all 15 cases. All dogs had unstable hip joints after closed reduction with reluxation confirmed with palpation and radiographs. The median time from trauma to surgery was 3 days (range, 1–8).
Surgical Procedure
A modified PCR was performed in all 15 dogs as previously described. Remnants of the joint capsule were sutured in 13/15 dogs. In 2 cases, the original capsule could not be sutured because it was no longer present or avulsed from the dorsal acetabular rim. Two acetabular screws were used in 13 cases, whereas 1 acetabular screw was used in 2 cases that had capsular tears confined to the cranial aspect. USP 6 suture was used in 13 cases and USP 3 was used in two cases (Table 1). Implants used for PCR are reported in Table 1. No intraoperative complications occurred. Postoperative radiographs obtained for all dogs confirmed appropriate hip reduction and congruency and positioning of the implants (Figure 2).
Citation: Journal of the American Animal Hospital Association 59, 2; 10.5326/JAAHA-MS-7244
Short-Term Outcome
One major complication was reported in the perioperative period (case 13), consisting of hip reluxation in-hospital 24 hr following surgery with no evidence of traumatic event such as a slip or fall (Table 2). No migration of orthopedic implants was noted. Despite the presence of moderate to severe hip dysplasia, femoral head and neck ostectomy was elected. Rupture of the synthetic coated polyester suture was noted at the time of revision surgery.
Median time to first clinical and radiographic recheck was 42 days (range, 31–77). Median lameness score was 0 (range, 0–2) (Table 2). Twelve of the 14 cases were clinically sound. Two dogs (cases 9 and 15) had mild lameness. All patients were considered to have excellent hip stability based on manual manipulation. Abnormal findings on recheck orthopedic examination included mild pain on hip range of motion in 2 dogs and mildly decreased hip extension in 1 dog. The remaining 11 dogs had no abnormalities on orthopedic examination. No dogs underwent physical rehabilitation therapy. Radiographic examination was unremarkable in 11/14 dogs, with adequate joint congruency and no evidence of implant migration or development of hip osteoarthritis. Two dogs (cases 4 and 5) developed an “apple-core” phenomenon and 1 dog (case 6) developed femoral head atrophy and loss of sphericity of the femoral head causing severe hip incongruency. Neither of these dogs had lameness or hip pain on orthopedic examination. Radiographic healing of concurrent femoral fractures was confirmed. In case 5, the untreated capital physeal fracture healed radiographically with development of moderate osteoarthritis. Minor complications occurred in 1 dog with superficial skin necrosis along the incision with no clinical evidence of surgical site infection. This was suspected to have occurred because of a lack of E-collar compliance, which resulted in the patient licking the incision. This superficial skin necrosis was successfully treated with local wound care (wound cleaning with antiseptics twice daily) and strict use of an E-collar without the need for anesthesia. The short-term major complication rate was 6.7% (1/15).
Long-Term Outcome
Median time to final clinical and radiographic recheck at the author’s institution was 44.8 mo (range, 19–75) (Table 3). Eleven dogs returned for long-term evaluation. At the time of final clinical examination, 10 of the 11 dogs were clinically sound and had excellent stability of the hip joint without any evidence of hip pain on orthopedic examination (Table 3). One dog (case 6) presented with mild lameness, decreased hip extension, and dorsal displacement of the greater trochanter on orthopedic examination with an Ortolani negative sign.
Radiographic examination was unremarkable in 7/11 dogs with adequate joint congruency and no evidence of implant migration or development of osteoarthritis. Two dogs (cases 2 and 9) developed mild hip osteoarthritis. One dog (case 6) had radiographic signs consistent with a chronic capital physeal fracture of the femur explaining the dorsal displacement of the greater trochanter on clinical examination. In this dog, the owners did not report any trauma between the short- and long-term follow-up appointments. There was no lack of owner compliance regarding the postoperative restriction and the dog was not overactive. Femoral head and neck ostectomy was discussed with the owners but declined because of financial constraints. The two dogs (case 4 and 5) that had an apple-core lesion identified at the time of short-term follow-up evaluation demonstrated worsening femoral neck atrophy, but neither had lameness or hip pain noted on orthopedic examination (Table 3).
The owners were asked to subjectively grade their dog’s outcome as previously described (Table 3).18 Ten of 11 dogs regained full function and the remaining dog (case 6) had acceptable function. Three dogs (cases 3, 8, and 15) did not return for long-term follow-up. However, telephone interviews with the owners at a median of 4.6 yr (range, 2–7) postoperatively revealed normal limb function and absence of complications in all 3 cases. Of the 7 dogs used for performance activities, all returned to sport. The long-term major complication rate was 7.1% (1/14).
Discussion
In the present study, 13/15 (87%) dogs with traumatic CHL surgically treated with the described PCR technique had any functional deficit detected during owner and surgeon assessments at last follow-up (>1 yr after surgery) with 7/7 dogs with uses other than companionship achieving their previous level of performance activity. The major complication rate was relatively low at only 2/15 (13.3%) dogs after following up with patients for a minimum of 1 yr. In our patient population, body weight ranged from 6.1 to 68 kg, suggesting that the technique described may be applied in dogs of different sizes.
Several reports have documented clinical outcomes of PCR technique.13–15,20 In the Allen et al. study, of the 5 dogs that underwent PCR, although no complications developed, functional outcome was not reported.13 Johnson and Braden reported full to acceptable function at a median follow-up of 22 mo in 11/17 (65%) dogs based only on a telephone interview.14 In the Belge et al. study, no reluxation occurred in 6 dogs, but only a 4 wk postoperative radiographic follow-up was reported.20 Results of another study showed a 66.6% success rate in 22 dogs, but the follow-up was short term at only 4–10 wk.15 In contrast, our study, which enrolled similar case numbers, reported both a higher success rate (i.e., maintained hip reduction and achieved full function) and a longer follow-up at 13/15 (87%) dogs and at a median of 3.8 yr, respectively.
The PCR technique has been previously described with the use of an osteotomy and transposition of the greater trochanter.13–15 A modification of the original Allen surgical technique was used in our case series and allowed for placement of acetabular screws using a standard craniolateral approach to the hip joint, obviating the need for greater trochanter osteotomy. Although trochanteric osteotomy would have improved visualization, especially for the placement of the caudal acetabular screw, the additional surgical trauma and orthopedic implants would have also increased the risk of implant-related complications.6 Similar to previous studies, we elected to drill the bone tunnel close to the joint capsule insertion.13–15 In contrast, Belge et al. described a modification of the PCR technique with a bone tunnel drilled within the greater trochanter.20 Although hip stability was achieved in all six dogs with no reluxation cases, this anatomical configuration did not mimic normal capsule joint attachments.
In our study, we elected to use polyester suture, which is a non-absorbable, braided, sterile, surgical suture composed of ethylene terephthalate and coated with polybutilated. This is because nonabsorbable, multifilament, orthopedic sutures are thought to be stronger and stiffer and undergo less elongation than comparably sized monofilament sutures.21–23 We believe this makes them an ideal choice for the PCR technique. We used large sizes of polyester suture material to maintain good stability until sufficient, mature scar tissue formed.5,6 One of the five cases in Allen’s study also used braided polyester in the PCR procedure.13 In our study, no surgical site infection developed, which may be due to a combination of factors, including rigorous aseptic technique, the use of an additional surgical incision drape to protect deeper tissues from skin flora, and the fact that the suture and implants used were well covered and protected by soft tissues. This is in contrast to a study in which dogs with tarsocrural luxation experienced a high rate of surgical site infection that often necessitated implant removal because of recurrent fistulating tracts.21
Spiked washers and screws were selected as anchor points for the prosthetic ligament in our study. Screw-washer combinations have been extensively used in veterinary surgery for ligament, joint capsule and tendon reattachment, and prosthesis placement and are still described as valuable implants for securing prosthetic ligaments particularly in cases of medial shoulder instability repaired with extraarticular stabilization.24,25 Alternatively, bone anchors can be used to anchor the suture material and offer the advantage of eliminating soft tissue interference while offering the versatility of suture and the holding power of an orthopedic implant.24–26 However, they are susceptible to failure at the bone-anchor interface, anchor-suture interface, suture-tissue interface, and other abrasive areas, such as bone edges or the knot itself. A biomechanical evaluation of the canine pelvis and femur found that screw/washer constructs failed at a higher maximum load (197.0 N ± 30.64) than bone anchor constructs (145.8 N ± 26.26).26
A non–weight-bearing sling was not used, and all dogs were allowed to place weight on the affected limb immediately postoperatively with the support of an abdominal sling. In patients with multiple orthopedic injuries, this is essential to permit ambulation.2 This is in contrast to previous studies in which most dogs had an external coaptation applied postoperatively in the form of an Ehmer sling for 7–10 days in combination with exercise restriction for 6 wk.13–15,20 Prolonged and rigid immobilization of joints has long been recognized as deleterious to articular cartilage and periarticular soft tissues and may result in major cartilage and subchondral bone alteration, proliferation of pericapsular connective tissue, and capsular and pericapsular contracture.1,11 The authors aimed for an early return to function, including controlled activity with short leash walks, and therefore refrained from using bandages.
Major complications were observed in 2/15 cases in the present study. One major complication, consisting of hip reluxation, occurred within 24 hr of surgery in a 6 yr old, 31 kg, mixed-breed dog with moderate to severe hip dysplasia and secondary osteoarthritis. Premature breakage of the prosthetic suture material was identified at the time of revision surgery. We suspect that this complication may have resulted from poor hip congruency and persistent subluxation due to hip dysplasia causing a shallow acetabular cup, although suboptimal surgical technique, unintentional trauma (such as a slip or fall in-hospital), suboptimal suture size selection, and a defective suture pack cannot be entirely ruled out. For this reason, attempting the PCR procedure again was not discussed with the owner. This case demonstrates the importance of case selection in the treatment decision-making process. Total hip replacement and excision arthroplasty should be considered for management of traumatic CHL with moderate or severe hip dysplasia.4,6 The other major complication that occurred in this study was identified at long-term follow-up 19 mo postoperatively and consisted of a chronic capital physeal fracture in the youngest dog. This patient, a 7.5 kg Pyrenean mountain dog, was 2 mo old at the time of the initial injury. Retrospective evaluation of preoperative, immediate postoperative, and 10 wk follow-up radiographs did not show evidence of concomitant type I Salter-Harris fracture of the femoral head. Only one screw was used to reduce the risk of acetabular growth plate disturbances. Implant removal, including the screws, washers, and polyester suture material, was recommended 3 wk postoperatively to limit acetabular and femoral head growth disturbances, but the owner scheduled this appointment later than desired (10 wk postoperatively). Interestingly, femoral head atrophy of the surgical limb and hip incongruency were noted at short-term follow-up and, in retrospect, may have been an indication of impending capital physeal fracture. It is possible that intraoperative damage to the ascending intracapsular arteries, the implant being maintained for a sustained period in a growing puppy, and potential suspected “tensioning effect” (no support references) of the prosthetic ligament on the hip may have contributed to this fracture.27 Further surgical intervention by means of a femoral head and neck ostectomy or a total hip replacement (following completion of growth) were proposed to the owner but declined for financial reasons.
Two dogs had evidence of an apple-core phenomenon, but there were no appreciable associated clinical signs. These dogs did not develop lameness and had excellent functional outcomes at long-term follow-up. This is unsurprising given that this condition tends to be self-limiting and subsequent collapse is rare even in dogs undergoing open reduction and internal fixation of femoral head fractures.27 Whether this radiographic lesion was due to the inciting trauma, surgical trauma, or a combination of the two remains unknown. However, given the patients’ previously mentioned clinical status, no further intervention was pursued. However, these patients may be predisposed to a major complication in the future, and further follow-up would be needed.
One limitation of the present study was the small number of cases that prevents determination of outcomes representative of a larger population with traumatic CHL. Retrospective design precludes standardization regarding the surgical technique, postoperative treatment, and follow-up and determining the exact cause of implant failure/reluxation and capital physeal fracture. Two patients’ final assessments of function depended on client assessment, rather than clinical assessment, which may have biased toward better outcomes. If the radiographic assessment in this study was performed retrospectively, another potential source of bias may have been failing to blind the surgeon to patient identity and randomize the images. However, we tried to control for certain variables by only enrolling dogs with traumatic CHL that were operated on and received rechecks from the same experienced orthopedic surgeon throughout the study period, precluding any blinded assessment of the radiographs.
In retrospect, it may have been more appropriate to avoid using the PCR technique in cases with concurrent hip dysplasia. In these cases, total hip replacement—or, as a salvage technique, femoral head and neck ostectomy—likely would have been more appropriate. An ex vivo evaluation of this technique on the impact on biomechanics of the hip, with cyclic testing and load to failure testing, has never been reported and would add further insight about its suitability for hip stabilization in a future study. Studies on this particular synthetic coated polyester suture material’s breaking strength, capillarity, creep, elasticity, fluid absorption, knot pull-out strength, knot strength, memory, plasticity, pliability, stress relaxation, suture pull-out value, and tensile strength are worth exploring and may represent future fields of research. Finally, subjective outcome assessment was not controlled for given that gait assessment using force plate analysis was not performed. Long-term prospective studies that use force plate analysis are advised.
Conclusion
In the present study, the treatment of traumatic CHL in dogs using a modified PCR technique with coated polyester as the prosthetic ligament was associated with long-term successful outcomes in 13/15 dogs and a relatively low major complication rate (13.3%). Additionally, all dogs involved in performance or sporting activities were able to return to those activities following treatment. This technique may be contraindicated in patients with hip dysplasia given the potential for persistent subluxation or reluxation following surgery for traumatic CHL. Long-term prospective studies that use force plate analysis, radiography, and/or arthroscopic hip examination should be considered. Further studies are likely needed before this technique can be recommended for widespread clinical use in dogs with traumatic CHL, especially given the small number of cases enrolled.
Photographs (A, B) showing the prosthetic capsule replacement suture in place for the right hip on a canine bone model. A single loop of polybutylate-coated polyester suture material is woven in a figure-of-eight pattern between two strategically placed screws and a bone tunnel drilled through the femoral neck. Observing the right hip from a lateral-to-medial direction, the acetabular screws were placed in the 1 and 3 o’clock positions. The cranial strand of the femoral suture was passed around the caudal screw. The remaining caudal strand was passed around the cranial screw and both ends were tightened while the limb was held in slight abduction and internal rotation. The blue-colored dotted circle marks the rectus femoris origin on this model.
Radiographs (A–F) of a 7 yr old, 24 kg, border collie (case 10) admitted with a traumatic right craniodorsal hip luxation (A, B). Hip luxation was repaired via open reduction and stabilized using two 3.5 mm cortical acetabular screws with spiked washers and a femoral tunnel (arrow) as anchor points for the polybutylate-coated polyester prosthetic ligament. Accurate reduction was obtained, and joint congruency was restored (C, D). Short-term follow-up radiographs obtained 45 days postoperatively demonstrated maintenance of hip reduction and joint congruency with no migration of orthopedic implants (E, F). At long-term recheck 33 months postoperatively, hip reduction and joint congruency were maintained with no migration of orthopedic implants (G, H). po, postoperatively.
Contributor Notes
The online version of this article (available at jaaha.org) contains supplementary data in the form of one appendix.
