Bias in Hand Surgical Randomized Controlled Trials: Systematic Review and Meta-Epidemiological Study.

PURPOSE: Inappropriately reported or conducted studies may decrease the quality of care due to under- or overestimation of the benefits or harms of interventions. Our aim was to evaluate how often hand surgical randomized controlled trials (RCTs) use and report adequate methods to ensure internal validity, and whether inadequate reporting or methods are associated with the magnitude of treatment effect estimates. METHODS: Data Sources were the Cochrane Central Register of Controlled Trials, MEDLINE, and Embase databases until November 2020. We included published RCTs investigating the effects of any surgical intervention in the hand and wrist region. We assessed internal validity using the Cochrane Risk of Bias (RoB) tool for 6 domains: selection, performance, detection, attrition, selective reporting, and "other" bias. We extracted the primary outcome and calculated the effect size for each study. We used mixed-effect meta-regression to assess whether the RoB modified the magnitude of the effects. RESULTS: For 207 assessed trials, the RoB was unclear or high for 72% in selection, 93% in performance, 88% in detection, 25% in attrition, 22% in selective reporting, and 34% in the "other" bias domain. Trials with a high or unclear risk of selection bias yielded 0.28 standardized mean difference (95% confidence interval, 0.02-0.55) larger effect sizes compared to studies with a low risk. Risks of bias for other domains did not modify the intervention effects. The risk for selection bias declined over time: the odds ratio for a high or unclear RoB was 0.90 (95% confidence interval, 0.85-0.95) per additional year of publication CONCLUSIONS: The internal validity and credibility of hand surgical RCTs can be improved by using established methods to achieve true randomization, blinding of the participants and study personnel, publishing the trial protocol and avoiding selective reporting of the outcomes, and reporting the trial as recommended in the Consolidated Standards of Reporting Trials statement. CLINICAL RELEVANCE: Clinicians should be aware that RCTs that do not use or report proper randomization and allocation concealment may overestimate the treatment effects.

Differential Diagnoses of Pediatric Upper Limb Masses.

PURPOSE: Upper limb masses are one of the most common presentations in the outpatient setting. However, there is a paucity of information in the literature regarding the epidemiology of upper-extremity masses in the pediatric population. The aim of this study was to determine the differential diagnoses and clinical characteristics in children aged ≤18 years presenting with upper limb masses. METHODS: A retrospective review of patients aged ≤18 years managed at our institution over a 5-year period was performed. We obtained information on patient demographics, clinical features, radiological investigations, intraoperative features, and histology. We also evaluated the correlation between the clinical and histopathological diagnoses in patients who underwent surgery. RESULTS: There were 141 upper limb masses in our series. The mean age at presentation was 12 years (SD, 5 years). The most common presenting complaints were asymptomatic swelling, pain, and paresthesia. The majority (128; 91%) of tumors were benign; there were 5 locally aggressive tumors and 6 malignant tumors. The dominant hand was involved in 60 patients. Of 140 patients, 43 (31%) patients had surgery. The procedures included incisional biopsy, excisional biopsy, wide resection, and reconstruction. One patient required a below elbow amputation for an osteosarcoma. CONCLUSIONS: Ten percent of cases represented malignant or locally aggressive disease. We have used our observations to develop a clinical algorithm that can assist clinicians in evaluating and managing children and adolescents presenting with upper-extremity masses. TYPE OF STUDY/LEVEL OF EVIDENCE: Prognostic IV.

Pigmented Nail Lesions: When to Observe, When to Biopsy, When to Widely Excise, and When to Amputate?

Pigmented nail lesions are challenging problems. The differential diagnosis is broad and ranges from common self-limiting conditions, such as subungual hematoma and infection, to potentially fatal conditions, such as subungual melanoma. Clinical assessment and adjuncts, such as dermoscopy and imaging, are usually insufficient to establish a diagnosis, and a nail bed biopsy is often required. However, this is not an innocuous procedure and may result in permanent nail deformity. In addition, subjecting every patient with nail pigmentation to a biopsy will result in an unacceptably high rate of negative test results. Furthermore, histopathologic diagnosis of subungual melanoma remains challenging for several reasons. Once the diagnosis of subungual melanoma is established, the definitive treatment is controversial because the existing guidelines have largely been adapted from those for cutaneous melanoma. This review presents an approach to the diagnosis and management of pigmented subungual lesions and subungual melanoma, in particular, on the basis of the latest available evidence.

A Cadaveric Study on the Utility of the Levator Scapulae Motor Nerve as a Donor for Brachial Plexus Reconstruction.

PURPOSE: The purpose of the study was to evaluate the utility of the levator scapulae motor nerve (LSN) as a donor nerve for brachial plexus nerve transfer. We hypothesized that the LSN could be transferred to the suprascapular nerve (SSN) or long thoracic nerve (LTN) with a reliable tension-free coaptation and appropriate donor-to-recipient axon count ratio. METHODS: Twelve brachial plexus dissections were performed on 6 adult cadavers, bilaterally. We identified the LSN, spinal accessory nerve (SAN), SSN, and LTN. Each nerve was prepared for transfer and nerve redundancies were calculated. Cross-sections of each nerve were examined histologically, and axons counted. We transferred the LSN to target first the SSN and then the LTN, in a tension-free coaptation. For reference, we transferred the distal SAN to target the SSN and LTN and compared transfer parameters. RESULTS: Three cadavers demonstrated 2 LSN branches supplying the levator scapulae. The axon count ratio of donor-to-recipient nerve was 1:4.0 (LSN:SSN) and 1:2.1 (LSN:LTN) for a single LSN branch and 1:3.0 (LSN:SSN) and 1:1.6 (LSN:LTN) when 2 LSN branches were available. Comparatively, the axon count ratio of donor-to-recipient nerve was 1:2.5 and 1:1.3 for the SAN to the SSN and the LTN, respectively. The mean redundancy from the LSN to the SSN and the LTN was 1.7 cm (SD, 3.1 cm) and 2.9 cm (SD, 2.8 cm), and the redundancy from the SAN to the SSN and the LTN was 4.5 (SD, 0.7 cm) and 0.75 cm (SD, 1.0 cm). CONCLUSIONS: These data support the use of the LSN as a potential donor for direct nerve transfer to the SSN and LTN, given its adequate redundancy and size match. CLINICAL RELEVANCE: The LSN should be considered as an alternative nerve donor source for brachial plexus reconstruction, especially in 5-level injuries with scarce donor nerves. If used in lieu of the SAN during primary nerve reconstruction, trapezius tendon transfer for improved external rotation would be enabled.

A Comparison of Casting Versus Splinting for Nonoperative Treatment of Pediatric Phalangeal Neck Fractures.

BACKGROUND: Phalangeal neck fractures account for 13% of pediatric finger fractures. Al Qattan type I (undisplaced) fractures are treated nonoperatively. There is increasing evidence that Type 2 (displaced) fractures achieve remarkable fracture remodeling with nonoperative treatment and patients frequently make a full functional recovery. The options available for nonoperative management of these fractures are either a plaster cast or a removable splint. We hypothesized that there would be no significant difference in radiologic outcome in pediatric phalangeal neck fractures (Types I and II) treated with splint or cast immobilization. METHODS: This is a retrospective study of patients aged 18 and below with phalangeal neck fractures treated nonoperatively from 2008 to 2017. Radiographs were compared at <1 week and >3 weeks after injury. Translation and angulation in coronal and sagittal planes were measured and compared using Student t tests. Baseline variables were compared using χ or Fisher exact tests. RESULTS: There were 47 patients with phalangeal neck fractures treated nonoperatively during the study period. There were 9 type I and 38 type II fractures. The mean age was 10 years with 40 males and 7 females. Fractures occurred in 33 dominant and 14 nondominant hands and involved 29 proximal and 18 middle phalanges. Nineteen children were treated in casts and 28 with removable splints. The mean duration of follow-up was similar between the 2 groups. The most affected phalanx was the proximal phalanx of the small finger and the most common fracture pattern was type IIA. There was no significant difference in clinical and radiologic outcomes between children who were treated in casts and those treated in removable splints. CONCLUSION: There was no difference in the clinical and radiologic outcomes in pediatric phalangeal neck fractures treated with cast or splint immobilization. Splinting has the added benefits of increased comfort and hygiene and we routinely offer splinting as a viable alternative in the nonoperative treatment of Al Qattan type I and type II phalangeal fractures. TYPE OF STUDY/LEVEL OF EVIDENCE: Level III-therapeutic studies.

Emergency Hand and Reconstructive Microsurgery in the COVID-19-Positive Patient.

The case spectrum in hand surgery is one of extremes-purely elective day surgery cases under local anesthesia to mangling limb injuries that require immediate, and frequently, lengthy, surgery. Despite the cancellation of most elective orthopedic and plastic surgical procedures, hand surgeons around the world continue to see a steady stream of limb-threatening cases such as severe trauma and infections that require emergent surgical care. With the increase in community-spread, an increasing number of COVID-19-infected patients may be asymptomatic or have mild, nonspecific or atypical symptoms. Some of them may already have an ongoing, severe infection. The time-sensitive nature of some of these cases means that hand surgeons may need to operate urgently on patients who may be suspected of COVID-19 infections, often before confirmatory test results are available. General guidelines for perioperative care of the COVID-19-positive patient have been published. However, our practices differ from those of general orthopedic and plastic surgery, primarily because of the focus on trauma. This article discusses the perioperative and technical considerations that are essential to manage the COVID-19 patient requiring emergency care, without compromising clinical outcomes and while ensuring the safety of the attending staff.

Structural Adaptations of the Primate Flexor Carpi Ulnaris After Tendon Transfer.

PURPOSE: Muscle remodeling occurs after tendon transfer. However, it is not known whether these adaptations are permanent and clinically significant. This study examined the early and late structural adaptations following a standard tendon transfer in a primate model. METHODS: A flexor carpi ulnaris (FCU) to extensor digitorum communis (EDC) transfer was performed in 8 adult monkeys. A sham operation was performed in the contralateral forearm. Four animals were sacrificed at 5 months (early cohort) and 4 at 16 months (late cohort). The transferred FCU, contralateral FCU, and EDC muscles were removed for analysis. Fiber length (FL), physiological cross-sectional area (PCSA), and gross morphology of the transferred FCU were compared with the contralateral EDC and FCU. RESULTS: In the early cohort, the FL of the transferred FCU was longer than the control FCU and similar to the contralateral EDC. The PCSA of the transferred FCU was lower than that of the control FCU but greater than the control EDC. In the late cohort, the difference in FL and PCSA between the transferred FCU and the control FCU persisted. The PCSA of the transferred FCU was similar to that of the control EDC. The bipennate transferred FCU had also undergone gross morphological changes to resemble the multipennate EDC. CONCLUSIONS: This study demonstrates, in a primate model, that the FCU undergoes structural adaptations to resemble the EDC following an FCU-to-EDC transfer. However, these adaptations are incomplete and not sustained over time. CLINICAL RELEVANCE: This study demonstrates that there is muscle plasticity in tendon transfers in a primate model. However, it is important to match potential donor muscles to the recipient during tendon transfer.

The Effect of Capitate Position on Coronal Plane Wrist Motion After Simulated 4-Corner Arthrodesis.

PURPOSE: The objective of this study was to examine the effect of altering the capitolunate relationship on coronal-plane wrist motion after scaphoidectomy and simulated 4-corner arthrodesis. Two positions of different capitolunate alignments were compared: "anatomic" (unchanged from pre-fusion) and "lunate-covered" (capitate translated to cover the lunate). We hypothesized that wrist resting posture would be altered and radial-ulnar motion would diminish after 4-corner arthrodesis in the lunate-covered position when compared with normal wrists. METHODS: Six human cadaveric limbs were disarticulated at the elbow and mounted on a custom jig. The resting position of the wrist was recorded with no load applied, followed by a load of 44 N applied to the flexor carpi radialis, extensor carpi radialis longus, and extensor carpi radialis brevis tendons to simulate radial deviation and to the flexor carpi ulnaris and extensor carpi ulnaris tendons to simulate ulnar deviation. Scaphoidectomy was performed and 2 methods of 4-corner arthrodesis with different capitolunate coronal alignments were studied in random order. Range of motion was compared using one-way analysis of variance and Bonferroni correction. RESULTS: The "lunate covered" wrist demonstrated significantly greater radial resting posture than that of the preoperative wrist. Under a 44 N load, the lunate-covered position had significantly greater radial motion than the preoperative radial motion. Wrists fused in the "anatomic" position did not differ significantly from the preoperative wrists in posture or range of motion. CONCLUSIONS: In this cadaveric model, complete covering of the capitate head by the lunate placed the wrist in increased radial deviation compared with the anatomic posture. Changes induced in the resting tension of the extrinsic wrist ligaments serve as a reasonable explanation for the increased radial posture and motion. In a clinical setting, these changes may affect postoperative wrist posture and function. CLINICAL RELEVANCE: Maintaining anatomic lunate position leads to preservation of greater wrist motion and anatomic alignment in a patient undergoing 4-corner arthrodesis.

Soft tissue complications of dorsal versus volar plating for ulnar shortening osteotomy.

PURPOSE: To compare the results and complications of fixed-angle dorsal locking plate fixation for ulnar shortening osteotomy (USO) with the conventional technique of volar plating. METHODS: We performed a retrospective review of 32 patients undergoing USO on 34 wrists and compared the outcomes of 16 consecutive cases with dorsal 2.4/2.7-mm fixed-angle plating and 18 consecutive cases with volar 3.5-mm plating. A minimum of 12 months' follow-up was used to assess outcomes. Primary outcomes were painful hardware and removal of symptomatic implants. Secondary outcomes were pain, Patient-Rated Wrist Evaluation, range of motion, time to union, grip strength, and complications. RESULTS: There were no significant differences in Patient-Rated Wrist Evaluation, pain score, range of motion, or time to union. Relative grip strength compared with the contralateral upper extremity in the dorsal group was higher than the volar group. After adjusting for hand dominance, dorsal plating was significantly associated with higher relative grip strength. There were 2 complications in the dorsal group, including one case with painful hardware. This was significantly lower than in the volar group, which had 10 complications including 2 nonunions and 6 cases of hardware-related soft tissue irritation. CONCLUSIONS: Both volar and dorsal plating techniques for USO yielded good functional outcomes. There was a higher incidence of painful hardware requiring removal of implants in the volar group. Based on these findings, we advocate dorsal plate position using a smaller fixed-angle plate for USO in ulnar impaction syndrome. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic III.

Thoracic outlet syndrome caused by synostosis of the first and second thoracic ribs: 2 case reports and review of the literature.

We present 2 cases of combined arterial and neurogenic thoracic outlet syndrome triggered by trauma in patients with congenital synostoses of the first and second ribs. These patients were successfully treated with supraclavicular resection of the first and second ribs and scalenectomy. We review these cases and the associated literature on thoracic outlet syndrome and rib synostosis.

Surgical treatment of osteochondroma of the proximal humerus: radiographic and early clinical results.

BACKGROUND: Symptomatic osteochondromas (OCEs) of the proximal humerus present a number of challenges, based upon their location and proximity to neurovascular structures. The purpose of this investigation was to evaluate the characteristics of these lesions and report the early results of surgical excision in children. METHODS: This is a retrospective case series of 31 pediatric patients with proximal humeral OCE treated with surgical excision. Radiographs and medical records were reviewed to evaluate tumor characteristics, treatment, and clinical results. The mean patient age was 13 (SD, 4) years, and the median follow-up was 11 months (range, 1 to 78 mo). RESULTS: From 1995 to 2009, 31 patients with proximal humeral OCE underwent surgical excision. Indications for surgery included pain in 25 (81%) and limited range of motion in 8 (26%). The OCE were most commonly posterolateral (23%) and posteromedial (16%). The site of OCE significantly influenced the extent of mass excision. OCEs located anteriorly, laterally, and posterolaterally had an average of 92% of mass excised (range, 69% to 100%), whereas those located posteromedially had an average of 68% of mass removed (range, 30% to 82%; P=0.02). Two patients (6%) had persistent postoperative pain, and 2 had recurrence. The deltopectoral approach was most commonly utilized (61%). For the posteromedial lesions, the direct medial approach led to more complete excision (79% vs. 51%). There were no neurovascular complications. CONCLUSIONS: Surgical excision of proximal humerus OCE led to favorable results, though persistent postoperative pain was seen with inadequate excision. Despite risks of neurovascular injury, a direct medial approach should be considered for posteromedial lesions. LEVEL OF EVIDENCE: Level IV-retrospective study.

The Role of Microsurgery in Coverage of Defects of the Hand.

Soft tissue defects of the hand may result from trauma, infection, vascular disease, and after resection of tumors. Microsurgery has evolved to a stage where it is relatively commonplace today but procedures such as free flaps still incur significant time, manpower, cost, and material resources. The aim of this article is to articulate the specific situations in hand reconstruction when microsurgery is superior to nonmicrosurgical reconstructive options. The benefits of microsurgical reconstruction include a variety of important metrics, such as improved function, better tissue match, less donor site morbidity, and reduced downtime for the patient.

Revisiting the reconstructive ladder for soft tissue reconstruction in the lower extremity.

Soft tissue reconstruction of the lower limb has seen a paradigm shift over the past two decades. Typically, these defects arise from trauma, infection or tumor. It is no longer enough to simply achieve coverage. Factors like patient-reported outcomes and aesthetic considerations are essential in the decision-making process. This is especially in light of increasing technological advancement, availability of dermal substitutes, microsurgical expertise and development of the field of microsurgical reconstruction as a whole with more novel flaps and techniques. Advancements in reconstructive modalities have also been equally matched by better emergency medical mobilization, transportation and access, early initiation of subspecialty care, accessibility and types of imaging, as well as oncological advances in radiotherapy and chemotherapy regimens. Yet, this has also meant that our patient profile has expanded to include older patients with more co-morbidities and other considerations such as frailty or the irradiated field which could influence what reconstructive modality is suitable and the goals of reconstruction specific to the patient. Previously deemed unsalvageable limbs are now being successfully reconstructed with good function and aesthesis. In the lower limb, this implicates the ability for early mobilization, range of motion and weight bearing which allow the patient to successfully partake in early rehabilitation. Expedient and reliable healing is also important in the oncological population where a proportion of these patients would need to go on to receive post-operative chemotherapy or radiotherapy. The reconstructive ladder has been what many reconstructive surgeons have been taught upon with regard to the basic principles of pre-operative planning and choosing the appropriate reconstructive modality. In this article, we examine the relevance of the reconstructive ladder in modern practice and the additional considerations in the approach to a soft tissue defect in the lower extremity.

Challenges and Solutions in Prosthetic Fitting of Digits after Flap Reconstruction.

Surgical reconstruction can restore length and function, but cannot adequately resolve the problem of disfigurement. Prosthetic fitting can play a complementary role in enhancing the aesthetic outcomes post reconstruction. However, complex reconstruction involving flaps coupled with the surgical imperative for limb length preservation can lead to outcomes where the reconstructed stumps are challenging to fit with prosthesis. This article describes how prosthetic fitting was tackled in a case of a triple-digit amputation after reconstruction that presented with finger stumps that were bulky, long and stiff in extension contracture, compounded by the presence of substantive scar tissues. We discuss major prosthesis modifications that were unconventional but necessary to enable fitting, the techniques involved, as well as the aesthetic and functional considerations behind the modifications. The results showed that enhanced aesthetic appearance, together with a marginal improvement in hand function, was achieved post-prosthetically, meeting the patient's and the clinical team's fitting objective. Level of Evidence: Level V (Therapeutic).

Aesthetic Considerations in Pollicisation Using the Buck-Gramcko Technique.

The Buck-Gramcko (BG) technique of pollicisation has stood the test of time and provides good to excellent prehensile function in thumb hypoplasia. Proponents of the technique favour it because it provides good exposure to the palmar neurovascular structures. However, the skin flap design may occasionally lead to a 'finger-like' appearance with a sharp interdigital cleft and a triphalangeal form. In this report, we describe some of the important aspects of the operative technique so that the outcome is aesthetically pleasing in addition to providing good function. Level of Evidence: Level V (Therapeutic).

Surgical Technique: Lateral Plate Osteosynthesis of Proximal Phalanx Fractures.

Dorsal plate fixation of proximal phalanx (PP) fractures is a conventional approach but interferes with the extensor mechanism and results in stiffness. Biomechanical studies have shown that laterally placed plates on the proximal phalanges are equally stable and rigid. This technique obviates the issue of tendon adhesion and may result in better postoperative range of motion and lower secondary procedures such as removal of implant and tenolysis. The low adoption of this technique may be related to lack of familiarity with the surgical approach. We describe our surgical technique with lateral plating of PP fractures and present our case that lateral plate osteosynthesis is an acceptable surgical fixation option for PP fractures, which extends the hand surgeon's armamentarium for more challenging and comminuted fractures.

Outcomes Associated with Moberg and Modified Moberg Flaps in Thumb Reconstruction: A Systematic Review.

Background: Appropriate thumb function is critical as it is makes up approximately 40% of the hand's function leading to the greatest influence in activities of daily living (ADLs). Local flaps are the primary option for thumb reconstruction, of which the Moberg flap has been reported to have the added advantage of its advancement capacity relative to other flaps. This systematic review aims to describe the outcomes of the Moberg advancement flap and its associated modifications for coverage of palmar thumb defects. Methods: Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed for the conduct of this systematic review. Medline, Embase, CINAHL and Cochrane Library were systematically searched to retrieve relevant citations. Title and abstract as well as full-text assessment were performed in duplicate. Full texts were extracted by one reviewer and data extracted was confirmed by a second. Complication rates and overall means were calculated for the appropriate outcomes. Results: A total of 1,794 citations were retrieved; 15 papers were retained, including 169 patients. The overall mean follow-up was 28.6 months (n = 5 studies). In 136 patients, there was 100% flap viability (n = 12 studies). With regard to thumb aesthetics, 92% (59/64 patients) had favourable outcomes (n = 6 studies). No evidence of postoperative flexion contractures (n = 0/56 patients, 5 studies) was found. Cold intolerance occurred at a rate of 29.8% (n = 17/57, 4 studies) and the infection rate was 10.3% (6/58 patients, 3 studies). Conclusions: Moberg/modified Moberg flaps are a safe option for thumb reconstruction given their associated postoperative outcome and complication profile. Level of Evidence: Level III (Therapeutic).

Functional use of esthetic hand prosthesis: A patient's perspective.

Published reports on the functional benefits of esthetic prosthesis are based on either anecdotal evidence or simplified, nonstandard forms of hand function evaluation performed by the researcher. It is not clear whether and how patients actually make functional use of their prosthesis on a daily basis. We report a case of a patient with a partial hand amputation who was initially ambivalent about fitting an esthetic prosthesis, but went on to make functional use of her prosthesis for activities of daily living, work, and social life at 3 years after injury. We present the patient's own assessment and video recordings, made without influence from rehabilitation personnel that demonstrates this functional use. From this case, we discuss the important factors of a favorable residual limb type, together with targeted modifications made to the prosthesis to optimize function.

Displaced humeral lateral condyle fractures in children: should we bury the pins?

BACKGROUND: The purpose of this investigation was to determine if leaving Kirschner wires exposed is more cost-effective than burying them subcutaneously after open reduction and internal fixation (ORIF) of humeral lateral condyle fractures. METHODS: A retrospective cohort study of all lateral condyle fractures treated over a 10-year period at a single institution was performed. Data on surgical technique, fracture healing, and complications were analyzed, as well as treatment costs. A decision analysis model was then constructed to compare the strategies of leaving the pins exposed versus buried. Finally, sensitivity analyses were performed, assessing cost-effectiveness when infection rates and costs of treating deep infections were varied. RESULTS: A total of 235 children with displaced fractures were treated with ORIF using Kirschner wires. Pins were left exposed in 41 cases (17.4%) and buried in 194 cases (82.6%); the age, sex, injury mechanisms, and fracture patterns were similar in both the groups. The median time to removal of implants was shorter with exposed versus buried pins (4 vs. 6 wk, P<0.001), although there was no difference in fracture union or loss of reduction rates. The rate of superficial infection was higher with exposed pins (9.8% vs. 3.1%), but this was not statistically significant (P=0.076). There were no deep infections with exposed pins, whereas the rate of deep infection was 0.5% with buried pins (P=1.00). Buried pins were associated with additional complications, including symptomatic implants (7.2%); pins protruding through the skin (16%); internal pin migration necessitating additional surgery (1%); and skin necrosis (1%). The decision analysis revealed that leaving pins exposed resulted in an average cost savings of $3442 per patient. This strategy remained cost-effective even when infection rates with exposed pins approached 40%. CONCLUSIONS: Leaving the pins exposed after ORIF of lateral condyle fractures is safe and more cost-effective than burying the pins subcutaneously. LEVEL OF EVIDENCE: Retrospective cohort study (level III).