Rupture of the thumb ulnar collateral ligament (UCL) is a frequent injury of the hand, commonly caused by sports injuries and falls onto an outstretched hand.1–5 The mechanism of injury usually involves hyperabduction or hyperextension of the metacarpophalangeal (MP) joint of the thumb.6 Disruption of the UCL leads to decreased pinch strength, pain, instability, and ultimately osteoarthritis. Some injuries can be associated with a Stener lesion, which is displacement of the ruptured ligament proximal to the adductor aponeurosis, effectively precluding healing without operative treatment.6
Acute injuries can be treated with immobilization or surgically with direct repair using bone anchors, direct repair using bone tunnels and pullout sutures, or tension band fixation of bony avulsions.7–9 If an injury is chronic, there are several operative treatment options, including ligament reconstruction with tendinous autograft or allograft, bone–soft tissue–bone autograft, or even fusion of the MP joint.10–12
The evidence regarding operative and nonoperative treatments of acute and chronic thumb UCL insufficiency is primarily limited to level IV retrospective case series and level V expert opinion. Therefore, the purpose of this systematic review is to combine patient outcomes from multiple unique studies and analyze the results of treatment of thumb UCL injury to determine the following:
- Whether a difference in clinical outcome exists between operative and nonoperative management of thumb UCL acute injuries;
- Whether a difference in clinical outcome exists between operative and nonoperative management of thumb UCL chronic injuries;
- Whether a difference in clinical outcome exists between repair and reconstruction of the thumb UCL for acute (less than 3 weeks) UCL injury;
- Whether a difference in clinical outcome exists between repair and reconstruction of the thumb UCL for chronic (more than 3 weeks) UCL injury;
- Whether a difference in clinical outcome after reconstruction of the thumb UCL exists between different choices of graft;
- Whether a difference in clinical outcome after operative treatment exists between acute and chronic UCL injuries.
The authors hypothesized that no difference exists in clinical outcomes between repair and reconstruction for acute UCL injury. However, thumb UCL reconstruction was hypothesized to be significantly better than repair for chronic UCL injury. In addition, operative management was hypothesized to result in greater patient satisfaction versus nonoperative treatment. It was hypothesized that no difference exists between different types of grafts used for thumb UCL reconstruction. It was hypothesized that surgical management results in equivalent outcomes for both acute and chronic UCL injury.
To address the purposes of this systematic review, the authors conducted a search of the following medical databases: PubMed, SPORTDiscus, CINAHL (Cumulative Index to Nursing and Allied Health Literature), and Cochrane Central Register of Controlled Trials. The search was performed on November 17, 2011, using PRISMA (Preferred Reporting Items for Systematic reviews and Meta-Analyses) guidelines.13 There were no limits placed on study publication date. All authors independently performed the search. Search terms included thumb, ulna(r), collateral, ligament, UCL, repair, reconstruction, and treatment. An example of the search strategy used for PubMed was “((((((ulnar[Title/Abstract]) AND collateral[Title/Abstract]) AND ligament[Title/Abstract])) OR ucl[Title/Abstract])) AND thumb[Title/Abstract].” Each abstract was manually reviewed, with potentially relevant full text of studies scrutinized for study inclusion or exclusion.
Levels I–IV evidence (according to the Oxford Centre for Evidence Based Medicine used by the American version of the Journal of Bone and Joint Surgery)14 were reviewed for inclusion in this review. Potentially inclusive articles were manually reviewed, discussed among the authors, and a decision was made regarding inclusion or exclusion. Furthermore, each bibliography was cross-referenced for potentially inclusive studies missed by the original search terms. In the event of disagreement among authors for study inclusion, the final decision was made by the senior author (HMA).
Inclusion criteria included English language studies after nonoperative or operative treatment of thumb UCL injuries with a minimum of 2 years mean follow-up. One study15 reported outcomes of 9 patients who had failed nonoperative treatment and underwent subsequent surgical repair. Therefore, these patients were included in the surgical group for analysis, as they did have more than 2 years minimum clinical follow-up after surgical treatment. Both repair and reconstruction (autograft and allograft) techniques were inclusive. Both purely ligamentous and bony avulsion injuries were included. Exclusion criteria were non-English studies and any study with less than 2 years mean follow-up. In addition, basic science, anatomical/histopathological, imaging, biomechanical, surgical technique, and studies on digits other than the thumb were excluded. Studies that duplicated patient populations from the same authors were excluded. A postsearch criterion of exclusion included expert opinion level V evidence studies or outcomes after management of radial collateral ligament (RCL) injury of the thumb.
Methodological quality of the study was assessed using the Quality Appraisal Tool (Table 1). This tool is a 12-item instrument, with each item possibly receiving a minimum integer of 0 and a maximum integer of 2 score points. A score of 0 was assigned if the item was either omitted or not performed. A score of 2 was assigned if the item was completely and accurately performed and reported. If the latter was executed only partially, a score of 1 was assigned. Consensus was obtained between the authors on assignment of study quality scores with any score dispute being decided by default assignment of the lower of the 2 disputing scores, as originally reported and recommended in the original study using the Quality Appraisal Tool.16
Study data collected and analyzed included subject demographics, number and gender of the subjects, number of nonoperative thumbs, sidedness, dominance, subject age, subject weight, and body mass index, throwing athlete status, mean duration follow-up, UCL injury classification, location of UCL injury (proximal, midsubstance, or distal), number of subjects with Stener lesions, number of subjects with avulsion fractures, mechanism of injury, injury chronicity (defined by 3 weeks based on repair vs reconstruction treatment dichotomy proposed by Smith in 1977),17 length of symptoms, graft type used (autograft or allograft), and implant used. All continuous data for independent and dependent variables were assimilated with weighted means and SDs based on the number of subjects or thumbs and the applicable means and SDs. The following clinical outcome parameters were extracted, if available, from each article identified for further review and scrutinized: pain, range of motion, key-pinch strength, stability testing, number of retears, range of motion posttreatment, pre–key-pinch strength and post–key-pinch strength, and complications. When applicable, these parameters were compared, integrated, summated, and statistically analyzed. Descriptive statistics were calculated. Continuous variable data were reported as mean ± SDs from the mean. Categorical variable data were reported as frequency with percentages. Data range was reported as minimum to maximum absolute values. Subject, surgical, and study data were compared using 2-sample and 2-proportion Z-test calculators with alpha 0.05 because of the difference in sample sizes between the compared groups. For all statistical analysis within all studies analyzed, P < 0.05 was deemed significant. If given within individual studies, the P values calculated by the authors of the individual studies were used and not retested because of a lack of subject-level data.
Of the 262 potentially relevant studies, 14 studies were identified for review11,15,18–29 (Figure 1). There were 61 studies eliminated as secondary for being in a language other than English. All but 2 studies were level IV evidence (there was one level II prospective cohort19 and one level III evidence retrospective comparative study20). Mean Quality Appraisal Tool score was 13.1 ± 3.5 (range, 8–19), which correlated with a 54.6% ± 14.5% quality rating. Subject demographics are reported in Table 2. No study directly compared nonoperative to operative treatment. No study reported the outcomes of nonoperative management of chronic UCL injury. No study directly compared the clinical outcome between repair and reconstruction of the thumb UCL for acute (less than 3 weeks) or chronic UCL injury. No study directly compared the different types of graft for UCL reconstruction.
Nonoperative Versus Operative Treatment
Nonoperative treatment led to high patient satisfaction for acute thumb UCL injury in 2 studies.23,29 Thirty-two subjects were treated with thumb-spica immobilization (30 were proximal phalanx avulsion fractures). Despite 11 of these patients (34%) remaining symptomatic, 5 remaining clinically unstable, and a 25% (n = 8 patients) nonunion rate, all 32 were satisfied with their clinical outcome (mean, 3 years follow-up). By nature of the definition of chronic UCL deficiency, patients with remote UCL injury have either been untreated or have failed prior nonoperative treatment (for various reasons such as pain, weakness, or instability) and gone on to necessitate surgical intervention. Thus, the latter group of patients (n = 93) was reported separately as chronically UCL-deficient operatively treated subjects' outcomes (Table 3) with attempted prior nonoperative treatment. In these patients, after failure of nonoperative treatment at anywhere from 1 month to more than 6 years, nearly all patients can achieve complete pain relief, normal pinch and grip strength, joint stability, and range of motion after surgical reconstruction. There was no significant difference in patient-specific and injury-specific parameters (subject age, gender, hand dominance, time to treatment, or length of follow-up) between patients with successful and failed nonsurgical treatment (P > 0.05 for each of the compared independent and dependent variables).
Acute Repair for UCL Injury
There were 6 studies that reported clinical outcomes after acute UCL repair using different techniques.20,24–26,28,29 Repair techniques (Table 4) included pullout suture over button with or without Kirschner wire immobilization, suture anchors, soft tissue periosteal suture, and arthroscopic Stener reduction with K-wire. All techniques improved clinical outcomes, including pain, motion, strength, and stability. Significantly better motion and strength and fewer complications were observed with suture anchors and early mobilization versus suture button and cast immobilization (P < 0.05).20 Only 3 patients in these 6 studies had residual laxity. Only 1 study reported significant loss of either MP and interphalangeal joint motion (P < 0.005).25 Except for 2 patients with significant postoperative weakness, full or near-full strength (key pinch and grip) was restored in all studies. Pain reduction was significantly improved in all subjects (P < 0.05).
Autograft Reconstruction for Chronic UCL Deficiency
There were 6 studies that reported clinical outcomes after autograft UCL reconstruction.11,18,19,21,22,27 Reconstruction techniques (Table 5) and grafts included palmaris longus via bone tunnels with or without K-wire MP joint fixation, palmaris longus with suture anchor fixation, iliac crest bone–periosteum–bone graft with cortical screw fixation, and extensor carpi radialis longus bone–tendon ligamentoplasty with titanium screw and suture anchor fixation. No study compared different graft types or fixation techniques. All techniques improved clinical outcomes, including pain, motion, strength, and stability (Table 5). Furthermore, there was no donor site morbidity from autograft harvest sites across all studies. According to the Glickel grading system, 51 excellent (80%) (joint stability not significantly different from unoperated thumb, less than 15% MP joint motion loss, no pain, no ADL limitations, and less than 15% loss of pinch strength), 11 good (17%), and 2 fair (3%) outcomes were observed. Metacarpophalangeal joint instability was either not observed or mild (up to 9 degrees). Key, pulp, and tip pinch and grip strength were either equivalent or only mildly weak compared with the contralateral thumb and hand in all subjects. Metacarpophalangeal joint motion ranged from 79% to 100% compared with the contralateral thumb. When assessed, most patients returned to their preinjury employment. Both x-ray and magnetic resonance imaging evidence confirmed no increase in MP joint osteoarthritis at up to 75 months, postoperatively. Other than 1 postoperative palmaris longus graft rupture requiring MP joint arthrodesis, no significant complications such as neurovascular injury or superficial or deep infection occurred.
There are many ways to manage both acute and chronic thumb UCL deficiency, and controversy persists as to the best treatment options. This systematic review has demonstrated excellent clinical outcomes (pain, strength, motion, and stability) after surgical treatment (repair and autograft reconstruction) of both acute and chronic UCL injury, without any significant difference between repair and reconstruction for acute and chronic injury, respectively. Nonoperative treatment of acute UCL injury (with or without a Stener lesion) frequently fails, leading to chronic pain, instability, and weakness, eventually prompting surgical intervention. Thus, a patient with delayed presentation of UCL injury can still achieve predictably successful outcomes, equivalent to acute repair, with autograft UCL reconstruction. No significant difference in the outcome was demonstrated between different types of autograft used for UCL reconstruction. Complications, failures, and reoperations are rare after surgical treatment of UCL injury.
The major arc of motion of the thumb MP joint is flexion and extension, although there is some abduction, adduction, and rotation.30 The stability of the MP joint derives from joint congruity, the true and accessory collateral ligaments, the volar plate, and the surrounding intrinsic muscles.31 The adductor pollicis supplies active support on the ulnar aspect, whereas the abductor pollicis brevis and flexor pollicis brevis provide dynamic stability on the radial border. The UCL has as its central function maintenance of ulnar stability of the joint, which is paramount for pinch grip. The mechanism of UCL injury is a forced abduction or rotation and hyperextension injury of the thumb at the MP joint.32 The most common region of rupture of the UCL is at the distal insertion or in the distal aspect of the ligament, leaving the proximal stump intact.32 Ulnar collateral ligament injuries can involve injuries to the dorsal capsule, palmar plate, and adductor aponeurosis.33 Avulsion fractures of the ulnar base of the proximal phalanx occur 20% to 30% of the time.17,34 Anywhere from 14% to 64% of UCL injuries have associated Stener lesions, which occur when the adductor aponeurosis is interposed between the ruptured end of the UCL and its site of proximal phalanx attachment.32
Nonsurgical treatment has been advocated for nondisplaced, or minimally displaced avulsion fractures of the UCL either with functional bracing35 or via thumb spica casting or splinting.23,36–38 Kuz et al recommend that most acute avulsion fractures of the thumb UCL be treated nonsurgically, with the exception of displaced fractures with more than 30% articular involvement or bony Stener lesions. Patients who fail nonoperative management have persistent thumb pain, decreased pinch strength, decreased grip strength, limited activities of daily living (especially opening jars and turning keys), continued instability, and early arthrosis.15,39 It is not entirely clear why patients fail nonoperative treatment, but some authors contend that failure may be because of irreducible displacement of the ruptured ligament.15 In patients who had failed nonoperative treatment, who were subsequently taken to surgery, it was found that many of the small avulsion fractures had rotated with the fragment's articular surface rotated out of the plane, precluding fracture healing.15
There is no uniformly agreed on surgical indication for UCL injuries to the MP joint of the thumb. Surgery has been recommended for fracture displacement, significant articular involvement, clinical instability, or fragment rotation.38 Chuter et al40 contend that surgical repair of acute UCL ruptures is the gold standard of treatment in the presence of gross instability, Stener lesions, or displaced avulsion fractures. Ritting et al30 assert that operative management of acute injuries is indicated when the thumb is without an endpoint to valgus stress testing. Surgical treatment has been advocated for all avulsion fractures of the UCL, as the area of articular cartilage is always greater than the fragment size.41 Abrahamsson et al42 maintain that a proximally displaced ligament, palpated proximal to the MP joint, is a more specific indication for surgery.
There is, however, agreement on the treatment goals for repair or reconstruction of the UCL, which are to obtain and maintain an anatomic reduction of the MP joint, reproduce the anatomic origin and the insertion of native ligament, ensure sufficient strength to allow early range of motion, and minimize donor site morbidity if autograft is used.19 Although most surgical undertakings result in good clinical and functional outcomes, there are postoperative complications, including stiffness and decreased range of motion (specifically, restricted flexion at the MP joint), failed reconstruction, infection, neuropraxia, continued pain, implant failure, graft failure, loosening, scarring, and arthrosis.30,43,44 It has been well documented that direct suture techniques fail in chronic injuries.33,45 When repair is attempted, nonanatomical repositioning of the UCL may contribute to the loss of joint motion.46
The limitations of this systematic review are reliant on the studies analyzed. There were considerable differences in the outcomes collected within the studies and between studies, which precluded the performance of a meta-analysis. Furthermore, the lack of patient-specific data precluded advanced statistical calculations, and weighted means from individual studies were the basis for comparison. Although the natural history of chronically untreated UCL injury eventually leads to pain and loss of function, surgery intervened in the studies present. Thus, the true natural history is yet unknown. Only prospective studies can determine this injury course. Selection bias was presented based on the variance in subject age, gender, hand dominance, injury chronicity, injury location, the presence or absence of bony avulsion, the presence or absence of Stener lesion, and the retrospective nature of most of the studies. There is also significant performance bias, as there are multiple different methods of treatment, providers, graft, suture, and fixation types, as well as methods and duration of immobilization. Transfer bias was present in the difference of length of follow-up, despite a minimum of 2 years, and the proportion of subjects who enrolled and completed that which was actually followed up. Detection bias was present in the inconsistent use of an invalidated outcomes tool (Glickel grading system), visual measurement of range of motion, different tools for strength and stability measurement, and the subjective nature of reporting weakness and stability. Further detection bias existed in that not all studies used each clinical outcome (eg, Glickel grade) or radiographic measure postoperatively. Furthermore, it is interesting that our study quality results using the Quality Appraisal Tool were as low as they were (mean 54% with a range of 33%-79%). The original study using this tool had a mean quality score range of 25% to 96% but had more than half of the studies scoring >75%.16 Despite these study limitations, this systematic review is strong in that it analyzes the largest number of studies and subjects in the literature managed with both nonoperative and operative means for acute and chronic UCL injury.
This systematic review has demonstrated excellent clinical outcomes (pain, strength, motion, and stability) after surgical treatment (repair and autograft reconstruction) of both acute and chronic UCL injury, without any significant difference between repair and reconstruction for acute and chronic injury, respectively. Nonoperative treatment of acute UCL injury (with or without a Stener lesion) frequently fails, leading to chronic pain, instability, and weakness, eventually prompting surgical intervention. Complications after surgical treatment of UCL injury are rare.
1. Bailie DS, Benson LS, Marymont JV. Proximal interphalangeal joint injuries of the hand. Part I: anatomy and diagnosis. Am J Orthop (Belle Mead NJ). 1996;25:474–477.
2. Benson LS, Bailie DS. Proximal interphalangeal joint injuries of the hand. Part II: treatment and complications. Am J Orthop (Belle Mead NJ). 1996;25:527–530.
3. Melone CP Jr, Beldner S, Basuk RS. Thumb collateral ligament injuries. An anatomic basis for treatment. Hand Clin. 2000;16:345–357.
4. Posner MA, Retaillaud JL. Metacarpophalangeal joint injuries of the thumb. Hand Clin. 1992;8:713–732.
5. Van Dommelen BA, Zvirbulis RA. Upper extremity injuries in snow skiers. Am J Sports Med. 1989;17:751–753.
6. Stener B, Petersen I. Electromyographic investigation of reflex effects upon effects upon stretching the partially ruptured medial collateral ligament of the knee joint. Acta Chir Scand. 1962;124:396–411.
7. Jupiter JB, Sheppard JE. Tension wire fixation of avulsion fractures in the hand. Clin Orthop Relat Res. 1987;214:113–120.
8. Kato H, Minami A, Takahara M, et al.. Surgical repair of acute collateral ligament injuries in digits with the Mitek bone suture anchor. J Hand Surg Br. 1999;24:70–75.
9. Strandell G. Total rupture of the ulnar collateral ligament
of the metacarpophalangeal joint of the thumb: results of surgery in 35 cases. Acta Chir Scand. 1959;118:72–80.
10. Catalano LW III, Cardon L, Patenaude N, et al.. Results of surgical treatment of acute and chronic grade III [corrected] tears of the radial collateral ligament of the thumb metacarpophalangeal joint. J Hand Surg Am. 2006;31:68–75.
11. Mitsionis GI, Varitimidis SE, Sotereanos GG. Treatment of chronic injuries of the ulnar collateral ligament
of the thumb using a free tendon graft and bone suture anchors. J Hand Surg Br. 2000;25:208–211.
12. Riederer S, Nagy L, Buchler U. Chronic post-traumatic radial instability of the metacarpophalangeal joint of the finger. Long-term results of ligament reconstruction. J Hand Surg Br. 1998;23:503–506.
13. Moher D, Liberati A, Tetzlaff J, et al.. Preferred reporting items for systematic reviews and meta-analyses: the PRISMA statement. PLoS Med. 2009;6:e1000097.
14. Obremskey W, Pappas N, Attallah-Wasif E, et al.. Levels of evidence in Orthopaedic Journals. J Bone Joint Surg Am. 2005;87:2632–2638.
15. Dinowitz M, Trumble T, Hanel D, et al.. Failure of cast immobilization for thumb ulnar collateral ligament
avulsion fractures. J Hand Surg Am. 1997;22:1057–1063.
16. Roy J, MacDermid J, Woodhouse L. Measuring shoulder function: a systematic review of four questionnaires. Arthritis Rheum. 2009;61:623–632.
17. Smith RJ. Post-traumatic instability of the metacarpophalangeal joint of the thumb. J Bone Joint Surg Am. 1977;59:14–21.
18. Lohman M, Vasenius J, Nieminen O, et al.. MRI follow-up after free tendon graft reconstruction of the thumb ulnar collateral ligament
. Skeletal Radiol. 2010;39:1081–1086.
19. Wong TC, Ip FK, Wu WC. Bone-periosteum-bone graft reconstruction for chronic ulnar instability of the metacarpophalangeal joint of the thumb–minimum 5-year follow-up evaluation. J Hand Surg Am. 2009;34:304–308.
20. Katolik LI, Friedrich J, Trumble TE, et al.. Repair of acute ulnar collateral ligament
injuries of the thumb metacarpophalangeal joint: a retrospective comparison of pull-out sutures and bone anchor techniques. Plast Reconstr Surg. 2008;122:1451–1456.
21. Fusetti C, Papaloizos M, Meyer H, et al.. The ECRL bone-tendon ligamentoplasty for chronic ulnar instability of the metacarpophalangeal joint of the thumb. Chir Main. 2005;24:217–221.
22. Oka Y, Harayama H, Ikeda M. Reconstructive procedure to repair chronic injuries to the collateral ligament of metacarpophalangeal joints of the hand. Hand Surg. 2003;8:81–85.
23. Kuz JE, Husband JB, Tokar N, et al.. Outcome of avulsion fractures of the ulnar base of the proximal phalanx of the thumb treated nonsurgically. J Hand Surg Am. 1999;24:275–282.
24. Ryu J, Fagan R. Arthroscopic treatment of acute complete thumb metacarpophalangeal ulnar collateral ligament
tears. J Hand Surg Am. 1995;20:1037–1042.
25. Downey DJ, Moneim MS, Omer GE Jr. Acute gamekeeper's thumb. Quantitative outcome of surgical repair. Am J Sports Med. 1995;23:222–226.
26. Jackson M, McQueen MM. Gamekeeper's thumb: a quantitative evaluation of acute surgical repair. Injury. 1994;25:21–23.
27. Glickel SZ, Malerich M, Pearce SM, et al.. Ligament replacement for chronic instability of the ulnar collateral ligament
of the metacarpophalangeal joint of the thumb. J Hand Surg Am. 1993;18:930–941.
28. Bostock S, Morris MA. The range of motion of the MP joint of the thumb following operative repair of the ulnar collateral ligament
. J Hand Surg Br. 1993;18:710–711.
29. Lane LB. Acute Grade III ulnar collateral ligament
ruptures. A new surgical and rehabilitation protocol. Am J Sports Med. 1991;19:234–237; discussion, 237–238.
30. Ritting AW, Baldwin PC, Rodner CM. Ulnar collateral ligament
injury of the thumb metacarpophalangeal joint. Clin J Sport Med. 2010;20:106–112.
31. Sakellarides HT, DeWeese JW. Instability of the metacarpophalangeal joint of the thumb. Reconstruction of the collateral ligaments using the extensor pollicis brevis tendon. J Bone Joint Surg Am. 1976;58:106–112.
32. Stener B. Skeletal injuries associated with rupture of the ulnar collateral ligament
of the metacarpophalangeal joint of the thumb. A clinical and anatomical study. Acta Chir Scand. 1963;125:583–586.
33. Kaplan EB. The pathology and treatment of radial subluxation of the thumb with ulnar displacement of the head of the first metacarpal. J Bone Joint Surg Am. 1961;43-A:541–546.
34. Hintermann B, Holzach PJ, Schutz M, et al.. Skier's thumb–the significance of bony injuries. Am J Sports Med. 1993;21:800–804.
35. Pichora DR, McMurtry RY, Bell MJ. Gamekeepers thumb: a prospective study of functional bracing. J Hand Surg Am. 1989;14:567–573.
36. Louis DS, Huebner JJ Jr, Hankin FM. Rupture and displacement of the ulnar collateral ligament
of the metacarpophalangeal joint of the thumb. Preoperative diagnosis. J Bone Joint Surg Am. 1986;68:1320–1326.
37. Landsman JC, Seitz WH Jr, Froimson AI, et al.. Splint immobilization of gamekeeper's thumb. Orthopedics. 1995;18:1161–1165.
38. Kozin SH, Bishop AT. Gamekeeper's thumb. Early diagnosis and treatment. Orthop Rev. 1994;23:797–804.
39. Sollerman C, Abrahamsson SO, Lundborg G, et al.. Functional splinting versus plaster cast for ruptures of the ulnar collateral ligament
of the thumb. A prospective randomized study of 63 cases. Acta Orthop Scand. 1991;62:524–526.
40. Chuter GS, Muwanga CL, Irwin LR. Ulnar collateral ligament
injuries of the thumb: 10 years of surgical experience. Injury. 2009;40:652–656.
41. Arnold DM, Cooney WP, Wood MB. Surgical management of chronic ulnar collateral ligament
insufficiency of the thumb metacarpophalangeal joint. Orthop Rev. 1992;21:583–588.
42. Abrahamsson SO, Sollerman C, Lundborg G, et al.. Diagnosis of displaced ulnar collateral ligament
of the metacarpophalangeal joint of the thumb. J Hand Surg Am. 1990;15:457–460.
43. Engelhardt JB, Christensen OM, Christiansen TG. Rupture of the ulnar collateral ligament
of the metacarpophalangeal joint of the thumb. Injury. 1993;24:21–24.
44. Breek JC, Tan AM, van Thiel TP, et al.. Free tendon grafting to repair the metacarpophalangeal joint of the thumb. Surgical techniques and a review of 70 patients. J Bone Joint Surg Am. 1989;71:383–387.
45. Frykman G, Johansson O. Surgical repair of rupture of the ulnar collateral ligament
of the metacarpo-phalangeal joint of the thumb. Acta Chir Scand. 1956;112:58–64.
46. Bean CH, Tencer AF, Trumble TE. The effect of thumb metacarpophalangeal ulnar collateral ligament
attachment site on joint range of motion: an in vitro study. J Hand Surg Am. 1999;24:283–287.