Humeral Intracondylar Fissure in Dogs

Long-Term Outcome and Complications after Transcondylar Screw Placement for Canine Humeral Intracondylar Fissure

OBJECTIVE

 The aim of this study was to report postoperative complications and long-term outcomes following transcondylar screw placement for humeral intracondylar fissure (HIF).

STUDY DESIGN

 It was a retrospective single-centre case series. Medical records (2018-2022) were reviewed for dogs with HIF treated with transcondylar screw placement. Data collected included signalment, concurrent orthopaedic disease, partial or complete HIF, surgeon, surgical approach, surgical technique and implant type, transcondylar screw angulation, postoperative complications and outcomes. Long-term outcome was assessed with owner questionnaire, orthopaedic examination and follow-up radiography. Statistical analysis was performed to identify risk factors predisposing to a complication or a poor outcome.

RESULTS

 Forty-seven dogs (57 elbows) met the inclusion criteria; long-term follow-up was available in 41 dogs (50 elbows). Minor and major medical complications were noted in seven and three elbows respectively. The total complication rate was 17.5%. Increasing age was significantly associated with a reduced risk of postoperative complications (p = 0.0051). No other risk factors were identified. A postoperative complication was not associated with a less than full outcome (p = 0.5698).

CONCLUSION

 Transcondylar screw placement for HIF is associated with a low complication rate and good outcome.

Impaired endochondral ossification in a skeletally immature dog: implications for femoral cleft formation and suspected incomplete femoral ossification

Historically, knowledge regarding congenital skeletal malformations in canines is poor. The Nomina Embryologica Veterinaria does not currently list any dysmorphia related to distal femoral fusion, and there is a significant absence of comprehensive descriptions of congenital defects in the veterinary literature. This paper reports on the radiographic and computed tomography (CT) characteristics of a skeletal abnormality in a seven-month-old crossbreed dog that presented for chronic right pelvic limb lameness as a result of secondary developmental patella luxation. Successful resolution of the lameness was achieved through concurrent surgical correction of the patella luxation and distal femoral cleft.

Computed Tomography Topographical Analysis of Incomplete Humeral Intracondylar Fissures in English Springer Spaniel Dogs

OBJECTIVE

 The aim of this study was to use computed tomography (CT) images obtained from English springer spaniels (ESS) with different sizes of humeral intracondylar fissure (HIF) to describe the typical shape, origin and a possible propagation pattern of HIF in this breed.

STUDY DESIGN

 It is a retrospective analysis of 32 elbow CT from 27 ESS with incomplete HIF. Measurements included HIF articular surface length, centre of HIF at articular surface relative to the caudal edge of the supratrochlear foramen (CHIF), HIF depth and sagittal area of fissure. Measurement of isthmus area and diameter was obtained for each elbow. Humeral intracondylar fissure measurements were analysed as proportions of the isthmus. For parts of analysis, elbows were grouped by HIF area as a percentage of isthmus area (%HIF) into less than 20% (n = 10), 20 to less than 40% (n = 8), 40 to less than 60% (n = 9) and 60 to less than 90% (n = 5).

RESULTS

 The mean isthmus diameter was 12.31 mm (range: 10.96-13.69 mm). Mean CHIF for %HIF groups less than 20%, 20 to less than 40%, 40 to less than 60% and 60 to less than 90% were 57, 74, 86 and 96 degrees, respectively. The less than 20% group was significantly lower than 20 to less than 40% group (p = 0.035) and 40 to less than 60% and 60 to less than 90% groups (p < 0.001); the 20 to less than 40% group was significantly lower than the 60 to less than 90% group (p = 0.015). Humeral intracondylar fissure articular surface length increased in a sigmoidal fashion relative to %HIF, corresponding to segmental enlargement of the fissure as %HIF increases.

CONCLUSION

 In ESS, HIF typically originates approximately 57 degrees caudal to the supratrochlear foramen in the sagittal plane and may propagate in a segmental fashion with lesser propagation through the proximal intracondylar region.

Adjunctive fixation of the humeral epicondyle in a lateral condylar fracture model: Ex vivo comparison of pins and plates with a novel composite (AdhFix)

OBJECTIVE

To compare the biomechanical properties of using a novel composite construct (AdhFix) to an interfragmentary Kirschner wire or a reconstruction plate as adjunctive epicondylar stabilization in simulated lateral unicondylar humeral fractures.

STUDY DESIGN

Cadaveric biomechanical assessment.

SAMPLE POPULATION

Paired humeri harvested from skeletally mature dogs (14-41 kg), nine cadavers per group.

METHODS

Simulated lateral unicondylar humeral fractures were stabilized with a transcondylar 4.5 mm cortical screw placed in lag fashion. Adjunct fixations consisting of a novel composite incorporating 2.7 mm cortical screws on one side, and either a 2.7 mm reconstruction plate or a 1.6 mm Kirschner wire on the contralateral side, were tested within paired humeri. Repaired humeri were axially loaded to failure and construct stiffness, yield load, and ultimate load were obtained from the load-deformation curves.

RESULTS

In pairwise comparison, yield load was significantly higher for AdhFix group compared to the pin group, p = .016. No statistical significance was seen in the comparison between AdhFix group and the plate group, p = .25.

CONCLUSION

Adhfix was mechanically superior to K-wires, and comparable to plate fixation, for adjunctive fixation in a lateral humeral condylar model. Our results support further investigation of the novel composite for adjunct fracture fixation in lateral humeral condylar fractures.

CLINICAL SIGNIFICANCE

The novel composite tested may be a viable alternative for adjunct fixation of humeral condylar fractures, a technique that circumvents plate contouring.

Medial versus lateral transcondylar screw placement for canine humeral intracondylar fissures: A randomized clinical trial

OBJECTIVE

To determine the influence of screw direction on complications following transcondylar screw placement for the treatment of canine humeral intracondylar fissures (HIFs).

STUDY DESIGN

Equivalence, parallel group, randomized clinical trial.

SAMPLE POPULATION

Fifty-two client owned dogs (73 elbows).

METHODS

Transcondylar screw placement was randomized to either a medial or lateral approach. The primary outcome was the incidence of postoperative complications.

RESULTS

There were 37 cases in the lateral approach group and 36 cases in the medial approach group. There was a significantly greater proportion of postoperative complications following placement of transcondylar screws from a lateral to medial direction (p = .001). There were seven cases with complications (19%) in the medial approach group versus 23 cases with complications (62%) in the lateral approach group. The majority of complications were seromas (n = 13) and surgical site infections (n = 16) with 4 complications requiring further surgery. Implant area moment of inertia (AMI), normalized to bodyweight, was lower in dogs with a major complication (p = .037).

CONCLUSION

Transcondylar screws placed from lateral to medial for canine HIFs had a greater proportion of postoperative complications in this randomized clinical trial design. Implants with a lower AMI, relative to bodyweight, were more likely to lead to major complications.

CLINICAL SIGNIFICANCE

We recommend placing transcondylar screws from medial to lateral for canine HIFs to reduce the risk of postoperative complications. Relatively small diameter implants had an increased risk of major complications.

Influence of oblique proximal ulnar osteotomy on humeral intracondylar fissures in 35 spaniel breed dogs

OBJECTIVE

To investigate the effects of oblique proximal ulnar osteotomy (PUO) on the healing of humeral intracondylar fissure (HIF) in spaniel breed dogs.

STUDY DESIGN

Clinical retrospective study.

SAMPLE POPULATION

A total of 51 elbows from 35 spaniel dogs.

METHODS

An oblique PUO was performed in dogs diagnosed with HIF. The degree of healing of HIF was subjectively and objectively assessed on preoperative and long-term follow-up CT imaging. Objective assessment was performed by measuring the bone density in Hounsfield units (HU) of a rectangular region of interest (ROI) encompassing the entire hypoattenuated humeral fissure. Major and minor complications were recorded.

RESULTS

A total of 24 partial and 27 complete HIFs were diagnosed. The follow-up CT scan was performed at a median 18.5 months (range 10-49 months). Subjective assessment confirmed partial or complete healing of the HIF in 41 elbows (80.3%). Objective assessment confirmed a difference in mean HU of the HIF's ROI between preoperative (HU 640) and last follow-up CT images (HU 835) (p = .001). Young dogs (<14 months) had the highest increase in HU of the HIF's ROI. Major complications occurred in five dogs (6 limbs) of which four were related to the lack of healing of the fissure (7.8%).

CONCLUSION

Oblique PUO resulted in partial or complete healing of HIF and pain resolution in the majority of dogs.

CLINICAL SIGNIFICANCE

This study introduces an innovative approach to achieve healing of the HIF in the dog, which may help reduce the high complication rate traditionally associated with the use of transcondylar screws.

Long term outcomes of the Humeral Intracondylar Repair System for management of canine humeral intracondylar fissures and humeral condylar fractures

Objective

To document long-term client-reported clinical outcomes and complications for the Humeral Intracondylar Repair System (HIRS) for treatment of humeral intracondylar fissures (HIF) and humeral condylar fractures (HCF) in dogs.

Method

Data collection involved the review of clinical records and analysis of an owner questionnaire regarding complication occurrence and client-reported outcome. The "Liverpool Osteoarthritis in Dogs" (LOAD) instrument was incorporated into the questionnaire.

Results

Twenty-six cases of HIF and 14 cases of HCF were included in the study, with follow-up times of over 12 months (range 13-97 months). Thirty-seven out of 40 cases reached long-term follow up: 25 out of 26 HIF cases, 11 out of 11 lateral condylar fracture cases and one out of three dicondylar fracture cases. Two cases of HIF suffered a gradual return of lameness in the long term; both dogs had concomitant medial coronoid disease. No other complications were reported in the long term. Excluding cases with concurrent issues affecting exercise, the median LOAD score at follow-up was 4 and 5 (out of 52) for HIF and HCF cases, respectively. At long-term follow-up, 36 out of 37 cases were reported to have regained "full function of the limb."

Clinical significance

The results of this study, together with previously reported short and medium-term outcomes, support the use of HIRS for management of humeral intracondylar fissures and humeral condylar fractures.

Isolated fracture of the talus with asymptomatic contralateral talar fissure in two dogs

CASE HISTORY

Two adult male dogs were separately presented for acute-onset, severe hind limb lameness isolated to the tarsus. There were no prior orthopaedic concerns and there was no significant trauma associated with the onset of lameness in either case.

CLINICAL FINDINGS

Pain and effusion of the affected tarsus were found in both cases. Lameness was not responsive to oral analgesia. Radiography was insufficient to fully determine the extent of the damage in the tarsus; the fracture was visible in one case only. CT imaging demonstrated an isolated, lateral, trochlear ridge talar fracture in both cases and contralateral talar abnormalities of comparable location and direction to the fracture.

DIAGNOSIS

Isolated lateral trochlear ridge fracture of the talus without significant trauma or concurrent injury. Abnormalities of talus of the contralateral limb were demonstrated on CT imaging.

CLINICAL RELEVANCE

A previously unrecognised pathological process may affect the talus of adult dogs that could predispose them to develop fracture of the lateral talar ridge without significant trauma. Further investigations are required to determine the prevalence and risk of fracture associated with this abnormality.Abbreviations: HIF: Humeral intercondylar fissure.

Correlation between the Insertion Side of a Transcondylar Screw for the Surgical Management of Humeral Intracondylar Fissures in Dogs and the Incidence of Postoperative Surgical Site Infection

OBJECTIVE

 An increased rate of surgical site infection (SSI) following treatment of canine humeral intracondylar fissure (HIF) with a lateromedially (LM) placed transcondylar screw (TCS) compared with a mediolateral (ML) TCS has been previously postulated. We hypothesized that the direction of insertion of the TCS would not affect the incidence of postoperative SSI.

STUDY DESIGN

 It was single-centre retrospective study. Dogs with HIF confirmed by computerized tomography, treated by TCS placement (between 2008 and 2019) and with a minimum follow-up of 12 weeks, were included. The following data were recorded: signalment, presenting clinical signs, direction of placement and size of the utilized TCS, surgical and anaesthetic times, concurrent surgical procedures, presence of concomitant elbow pathology, perioperative and postoperative antibiotic usage and postoperative complications. Recorded data were analysed with a multinomial logistic regression model with a p-value less than or equal to 0.05.

RESULTS

 Thirty-five dogs (46 elbows) met the inclusion criteria. Median clinical follow-up interval was 52 weeks. Seven of thirty-one elbows with a ML TCS, and 4/15 elbows with a LM TCS developed SSI. Four of nine dogs that underwent bilateral single-surgery TCS placement developed SSI unilaterally.

CONCLUSION

 No significant difference was shown in short-term SSI occurrence between the ML and the LM direction of placement of the TCS.

Design and topographic evaluation of a canine humeral anatomic plating system (CHAPS) for humeral condylar fracture repair in spaniels

OBJECTIVE

To design a precontoured plating system for humeral condylar fracture repair in spaniels with humeral intracondylar fissure (HIF) and quantify accuracy of fit of the system on 3D printed bone models.

STUDY DESIGN

Experimental on 3D printed models.

METHODS

The plating system was based on morphometric data obtained from CT. Plates were applied to models and impression material was measured under the plates at points of interest to define plate bone gap (PBG). Data on locking screw interference on plate application were also obtained.

RESULTS

Eleven elbows models were plated. Statistical analysis to assess for any difference in PBG measurements between left and right humuri revealed two loci (3 and 17) under the lateral plate and two loci (3 and 17) under the medial plate. On cumulate portion analysis, 67% of lateral plate loci and 80% of medial plate loci had a PBG of ≤2 mm respectively. An incidence of 2.1% (3/143) screw interference occurred.

CONCLUSION

Design of a contoured plating system for application to humeral models from spaniels with HIF and its application with objective measurement of PBG is described. The majority of the loci measured under both lateral and medial plates had a BPG of ≤2 mm and the incidence of locking screw interference on plate application was low.

CLINICAL SIGNIFICANCE

This novel system may have application for the stabilization of humeral condylar fractures in spaniels avoiding the need for plate contouring and minimizing the incidence of locking screw interference.

Prevalence of incidental humeral intracondylar fissures in brachycephalic breed dogs in CT studies

Humeral intracondylar fissures (HIF) have been predominantly reported in spaniel breeds and proposed to be possible risk factors for humeral condyle fractures (HCF). We hypothesized that the prevalence of incidental HIF in French Bulldogs may be greater than that of other brachycephalic breeds. A retrospective, observational, prevalence study was performed using CT examinations of French bulldogs and other brachycephalic breed dogs presenting for an unrelated condition. Two European College of Veterinary Diagnostic and Imaging-certified radiologists reviewed the images of the humeral condyles of these dogs. A classification system was devised to grade the findings. We considered a Score 1 to be normal, Score 2 to have centralised sclerosis, Score 3 to have a partial fissure and Score 4 to have a complete fissure. A total of 228 elbows were reviewed from 122 dogs. Of this population, 145 elbows were from French Bulldogs, 54 were from Pugs, and the remainder were from a mix of other brachycephalic breeds. The prevalence of HIF (score 3 or 4) in elbows of the French bulldog, pug and other breed groups was 6.9% (CI 2.8-11%), 5.6% (CI 0-11.7%), and 3.4% (CI 0-10.15%), respectively. At a dog level, the prevalence of HIF (score 3 or 4 present in at least one elbow) was found to be 11.8% (CI 4.6-19%) in French Bulldogs, 11.1% (CI 0-22.9%) in Pugs, and 5.26% (CI 0-15%) in the other breed group. There was no significant difference between the breed groups. The inter-reviewer reliability for CT scoring of HIF based on Cohen's weighted kappa was low at 0.19.

Proximal Ulnar Osteotomy as a Treatment for Humeral Intracondylar Fissure in a Shetland Sheepdog

A seven-month-old male Shetland Sheepdog was presented for assessment of thoracic limb lameness of 3 weeks duration. Orthopaedic examination revealed severe discomfort in elbow extension, bilaterally. CT-scan confirmed presence of a complete humeral intracondylar fissure (HIF), bilaterally, and arthroscopic examination of both elbows confirmed the presence of the cartilaginous lesion previously reported in dogs suffering from HIF. A staged oblique proximal ulnar osteotomy was performed to address the humero-anconeal incongruency believed to be the cause of HIF formation. Orthopaedic examination performed 5 weeks after each surgical procedure confirmed that pain previously present on elbow manipulation had subsided. Follow-up examination performed 8 months after the second surgery revealed the dog to be sound at walking on the thoracic limbs with no discomfort present on elbow manipulation. Repeated CT scan confirmed complete healing of both HIFs. This is the first report documenting the presence of HIF in a Shetland sheepdog and complete healing of both HIFs following a proximal ulnar osteotomy.

Humeral condylar fractures and fissures in the French bulldog

OBJECTIVE

To report the configuration, risk factors, fixation methods and complication rates after repair of humeral condylar fractures (HCF) in French bulldogs, and report the presence of humeral intracondylar fissures (HIF) in this population as a possible predisposing factor.

STUDY DESIGN

Retrospective clinical cohort study.

SAMPLE POPULATION

Forty-four elbows.

METHODS

The medical records of dogs referred between January 2012 and December 2021 were searched for French bulldogs presenting with HCF. Signalment, fracture configuration, stabilization method and complication occurrence were obtained. Postoperative radiographs were assessed for implant positioning, and computed tomography (CT) scans were assessed for the presence and size of HIF in the contralateral elbow.

RESULTS

Lateral humeral condylar fractures represented 28/44 (63.6%) of HCF in French bulldogs. Repair with a transcondylar screw (TCS) and Kirschner-wire(s) (K-wire) were 7.62 times more likely to result in a major complication (95% CI: 1.43, 21.89; p = .01) compared to other methods. All incidences (7/7) of TCS migration were within the TCS + K-wire group. A HIF was identified in 18/31 (58.1%) dogs. Older animals were not significantly less likely to have a HIF than younger animals (p = .129).

CONCLUSIONS

Fracture stabilization with a TCS and K-wire(s) was associated with an increased risk of major complications and migration of the TCS. A HIF was present in the contralateral elbow of over half of the French bulldogs where CT was available.

CLINICAL SIGNIFICANCE

A HIF may be a predisposing factor of HCF in French bulldogs. Alternative methods of stabilization to a TCS and K-wire(s) should be used to reduce complication risk.

Treatment of Y-T Humeral Fractures with Polyaxial Locking Plate System (PAX) in 14 Dogs

The aim of this study is to report the results and to review the outcome of 14 cases of Y-T humeral fractures repair using paired polyaxial locking system (PAX) plates through a combined medial and lateral approach. Fourteen consecutive dogs, with traumatic humeral Y-T fractures, met the inclusion criteria. This study includes signalment, preoperative radiographs, type of implants, radiographic bone healing assessment, complications, range of motion (ROM) of the elbow and limb function evaluated at 120 days after surgery. Postoperative radiographs revealed adequate anatomic reconstruction, and in all cases, bone healing has been achieved. No implant failure was observed. Functional outcome was excellent in 7 dogs (no lameness and preserved ROM), good in 4 (slight lameness and moderate ROM reduction) and discrete in 2 (mild lameness and severe ROM reduction). Complications were encountered in 2/14 patients with implant-associated infection resolved after long-term antibiotic treatment and implant removal. The PAX system is shown to be a valid alternative for the treatment of Y-T humeral fractures, offering the benefit of polyaxial insertion of locking screws. The possibility of angle locking screws is helpful in the distal humeral bicondylar fractures, providing additional options for screw placement in juxtarticular fractures, avoiding fracture lines or other implants.

A Prevalence Study of Canine Humeral Condylar Fractures Over a Ten-Year Period at an Academic Teaching Hospital

Objective The aim of this study was to investigate the prevalence, breed predisposition and fracture conformation of humeral condylar fractures (HCF) over a 10-year period. Results were compared with published studies emanating from the United Kingdom exploring effect of breed on HCF.

Methods Data for all canine admissions to the Veterinary Teaching Hospital at Kansas State University were extracted for the period January 2010 to October 2020. Humeral fractures were recorded and further subclassified as medial, lateral and ‘T’/‘Y’ condylar fractures. The associations between HCF and subtypes with breed were assessed using univariate logistic regression with a comparison group. Multivariable logistic regression was used to evaluate the effect of breed while accounting for dog age, sex and neuter status.

Results Of the 44,952 canine patients seen during the study period, period prevalence (95% confidence interval [CI] for HCF was 0.26% [0.22, 0.31]). After adjustment for age and neuter status, French Bulldogs were 49 times more likely to be diagnosed with a HCF compared with the comparison breed group (odds ratio [OR], 49.0; 95% CI, 26.9–89.3). After adjustment for age and neuter status, Cocker Spaniels (OR, 42.8; 95% CI, 16.8–108.6), Boston Terriers (OR, 22.9; 95% CI, 11.0–47.9) and Brittany Spaniels (OR, 21.5; 95% CI, 7.3–63.1) had the next highest increase in HCF compared with the comparison group.

Conclusion Based on a study population from the United States, French Bulldogs were 49 times more likely to be diagnosed with a HCF compared with the comparison breed group.

Visibility of Transcondylar Screw Fractures in Standard and Extended Scale Computed Tomography Images

OBJECTIVE

 Application of extended computed tomography scale (ECTS) reconstruction to diagnose metal implant failure has been described in a single case report. The purpose of this study was to compare the features and visibility of humeral transcondylar screw fractures in standard CT scale (SCTS) and ECTS images.

STUDY DESIGN

 Case series: CT images of dogs with fractured transcondylar screws were retrospectively reviewed and described in both SCTS and ECTS images.

RESULTS

 Five dogs with a total of six transcondylar screw failures (five right and one bilateral) were reviewed. All cases had an ongoing humeral intercondylar fissure with varying degrees of stress remodelling. The fracture was seen in all screws on ECTS images, however only in three implants on SCTS images. The measured fracture gap was larger in ECTS images in all cases (range: + 0.14 mm to + 0.28mm). The three smallest fracture gaps were not seen on SCTS images. A subtle hypoattenuating streak (artefact) was visible adjacent to the screw fracture in 5/6 of cases using SCTS images. All screw fractures occurred parallel and often slightly medial to the humeral intercondylar fissure.

CONCLUSION

 Implant failure is only seen with larger fracture gaps in SCTS images, with 3/6 screw fractures not visible in SCTS compared with ECTS. A hypoattenuating streak extending perpendicular to the implant in SCTS images is suggestive of screw fracture even if this is not directly visible.

Repair of Fractures of the Lateral Aspect of the Humeral Condyle in Skeletally Mature Dogs with Locking and Non-Locking Plates

OBJECTIVE

 The aim of this study was to report the functional outcome and complications following transcondylar screw and epicondylar plate fixation of skeletally mature dogs with fractures of the lateral aspect of the humeral condyle using a string of pearls, limited contact dynamic compression plate (LC-DCP) or locking compression plate (LCP).

STUDY DESIGN

 This study was a retrospective review of clinical records, radiographic images and canine brief pain inventory evaluation with a supplementary non-validated questionnaire.

RESULTS

 Thirty-one fractures in 29 dogs were included. The majority of dogs were Spaniels (23/29). Thirty fractures had evidence of humeral intracondylar fissure. Sixteen fractures had string of pearls, eight LCP and seven LC-DCP. There were two minor complications and three major complications. Perioperative (median: 6 weeks, range: 6-12) outcome was considered fully functional for 24 fractures and acceptable for 6 fractures. One dog had an unacceptable outcome due to the failure of an LCP that healed following revision surgery. Fractures with radiographic follow-up had a persistent visible intracondylar fracture line in 20/26. Twenty-six of twenty-seven owners perceived an excellent outcome (median: 135 weeks, range: 25-246).

CONCLUSION

 Repair of fractures of the lateral aspect of the humeral condyle with a transcondylar screw and epicondylar plate has a good perioperative, mid- and long-term outcome with 10% major complication rate, despite incomplete or non-union of the intracondylar fracture in 20/26 elbows.

Biomechanical comparison of humeral condyles with experimental intracondylar fissures immobilized with a transcondylar positional or a lag screw: An ex-vivo study in dogs

OBJECTIVE

To compare the axial biomechanical properties of intracondylar humeral osteotomies fixed with 4.5 mm transcondylar positional or cortical lag screws.

STUDY DESIGN

Ex vivo study.

SAMPLE POPULATION

Paired humeri from 21 canine cadavers.

MATERIALS AND METHODS

An intracondylar osteotomy was created on each humerus to mimic an intracondylar fissure. Paired humeri were randomly assigned to fixation with a positional or a lag screw. All specimens were radiographed postinstrumentation to document proper screw placement. Axial load was applied to the distal articular surface of the trochlea at a rate of 1 mm/s until a 40% decrease in load was measured. Specimens were assessed for mode of failure with visual inspection and radiographs.

RESULTS

Stiffness (1236.7 ± 181 N/mm vs. 1050.8 ± 265 N/mm), yield load (3284.3 ± 1703 N vs. 2071.1 ± 740 N), and maximum load (7378.0 ± 1288 vs. 5793.7 ± 2373 N) were greater in constructs fixed with a positional rather than a lag screw (p = .0008, .044, and .040, respectively).

CONCLUSION

In our model, mechanical properties were improved when the transcondylar osteotomy was stabilized with a 4.5 mm positional screw rather than a lag screw.

CLINICAL SIGNIFICANCE

This ex vivo study suggests that a transcondylar lag screw and positional screw are not biomechanically equal. Additional in vivo studies are need to help with clinical decision making when prophylactically treating HIF.