Mid-Carpal Joint Sparing Procedure for Idiopathic Avascular Necrosis of Capitate

Abstract

Background  Avascular necrosis of the capitate (AVNC) is an uncommon pathology of the wrist. Several procedures have been described for the treatment of AVNC. The type of treatment varies depending upon the stages. In early stages, revascularization procedures are performed. If secondary osteoarthritis develops, then the treatment options include intercarpal fusion, four corner fusion, prosthesis replacement of the capitate, tendon interposition, and wrist arthrodesis. No long-term study is available for choosing an appropriate method of the treatment for AVNC.

Case Description  Herein, we report a case of AVNC that was managed by hemi-resection of the capitate with capito-hamate fusion and tendon interposition. One year after surgery, patient was asymptomatic and radiographs revealed fusion of capito-hamate joint and maintenance of the mid-carpal joint space. There was no evidence of carpal collapse.

Literature Review  All the literature about mid-carpal joint sparing (MCJS) procedures has been reviewed in this report. This is a goal behind writing of this case report as there have been very few publications about these procedures.

Clinical Relevance  This case illustrates the successful treatment of AVNC by MCJS procedure. The intercarpal fusion and the four corner fusion are one time procedures, and these can be used if the MCJS procedure fails or sometimes, as primary procedure, if the patient gives consent for the same. It appears prudent to save arthrodesis procedures for the future.

Jonsson described the avascular necrosis of the capitate (AVNC) in 1942. ¹ It is a rare entity and there have only been few case reports or very small case series about it in literature. It is generally seen among the younger age groups, etiology of which is not completely understood, but there are multiple hypothesizes associated with it and most of them correlate with vascular supply of capitate. The classification of the AVNC has been described and its treatment depends upon the cartilage involvement of the head of the capitate. Mid-carpal fusion procedures such as four corner fusion and scapho-capito-luno-triquetrum fusion procedures have been used. These carry inherent chances of decreased range of motion. The intercarpal fusion and the four corner fusion are one time procedures, and these can be used if the MCJS procedures fail or sometimes, as primary procedure, if the patient gives consent for the same. It appears prudent to save arthrodesis procedures for the future.

Herein, we describe an old technique with newer modification, as hemi-resection of the capitate with tendon interposition and capito-hamate fusion for idiopathic AVNC. This fusion allows for a stable capitate and may be an adjunct to other resurfacing options. The chances of carpal collapse due to this fusion may decrease further. Although the interposition may not be an essential component, we have done tendon interposition as the capito-hamate fusion was done with a single screw, and the interposition would have supported the assembly while maintaining the mid-carpal joint space. We have also reviewed the mid-carpal joint sparing (MCJS) procedures in this report.

Case Report

A 27-year-old, right hand dominant, female presented with complaint of pain over the right wrist since 8 months. The pain was intermittent, dull boring in nature, aggravating with her daily household activities, and calming down by analgesics. She was a housewife who did all household work by herself. There was no history of steroid intake, smoking, trauma, any prolong disease, and multiple joint pains. On examination, there was tenderness over the dorsal wrist (directly over the capitate); the range of movement of the wrist was as flexion 0 to 20 degrees, extension 0 to 30 degrees, radial deviation 0 to 10 degrees, and ulnar deviation 0 to 20 degrees. The visual analog score at rest was 7/10, and the grip strength was 20 kg (measured through hydraulic hand dynamometer, Inc. Baseline). The radiographs of the wrist were done. The sclerosis of the capitate with subchondral cyst formation at proximal capitate and decreased mid-carpal space was seen in the radiographs ( Fig. 1A–C ). The magnetic resonance imaging (MRI) revealed hypointense signal intensity with variegated appearance of the capitate, the short tau inversion recovery sequence showed areas of hyperintensity in the capitate. Loss of the cartilage and irregular cartilage at the capitate head was visible. There was decrease in the space of the mid-carpal joint ( Fig. 2A, B ). The MRI appearance confirmed the diagnosis of type 3 AVNC.

Fig. 1.

The radiographs of the wrist as postero-anterior ( A ), oblique ( B ), and lateral ( C ) views reveal sclerosis of the capitate and subchondral cyst formation. The decrease in mid-carpal joint space is visible.

Fig. 2.

The magnetic resonance imaging of the wrist reveals avascular necrosis of the capitate. Hypointense signal intensity with variegated appearance of the capitate ( A ), the short tau inversion recovery sequence showed areas of hyperintensity in the capitate, and loss of the cartilage and irregular cartilage at the capitate head was visible ( B ).

The patient underwent diagnostic arthroscopy of the wrist that showed loss of cartilage of the proximal capitate ( Fig. 3A, B ). Synovectomy was done through the mid-carpal portals of wrist arthroscopy; rest of the procedure was performed by open approach. Ligament sparing capsulotomy of the wrist was done. The resection of proximal half of the capitate resection was performed ( Fig. 4A ). The fusion of the remaining capitate and hamate was done by removing the cartilage in this joint and placing the crushed pieces of the removed capitate between capitate and hamate. The capitate and hamate were stabilized together by a 2.4-mm and headless cancellous screw (AO Synthes,). The tendon of extensor carpi radialis longus tendon was identified. Its ulnar and longitudinal half was harvested by standard minimally invasive method while keeping the distal attachment of the tendon intact ( Fig. 4B ). The tendon was sutured on itself with absorbable suture to make an anchovy ball like structure ( Fig. 4C ), and interposition of tendon ball was done. The capsular closure was done. A below elbow splint was given for 6 weeks. The biopsy of the sent sample confirmed the diagnosis of osteonecrosis of the capitate. The patient received postoperative physiotherapy for 12 weeks after splint removal and showed satisfactory improvement in function. On evaluation at 1 year, the patient had a VAS pain score of 2/10, grip strength of 34 kg (measured through hydraulic hand dynamometer, Inc. Baseline), and the range of movement showing flexion 0 to 45 degrees, extension 0 to 40 degrees, radial deviation 0 to 20 degrees, and ulnar deviation 0 to 30 degrees. The radiographs at 1-year follow-up revealed fused capito-hamate joint and maintenance of the mid-carpal joint, there was no evidence of carpal collapse ( Fig. 5A, B ).

Fig. 3.

Cartilage loss of the head of the capitate was noted during arthroscopy ( A ) and the synovitis ( B ) was prominent in the mid-carpal joint.

Fig. 4.

The loss of cartilage was seen during open procedure also ( A ), ulnar half of extensor carpi radialis longus tendon was harvested as minimally invasive procedure ( B ) and made into anchovy ball ( C ).

Fig. 5.

The radiographs of the wrist at 1-year follow-up as postero-anterior ( A ) and lateral ( B ) views reveal fusion of capito-hamate joint. The mid-carpal joint space is maintained. There are no signs of carpal collapse.

Discussion

Avascular necrosis of capitate (AVNC) is rare. Kienbock's or Preiser's diseases are common avascular necrosis (AVN) pathologies of carpal bones. AVNC differs from the avascular necrosis of lunate and scaphoid. The AVNC is usually secondary and rarely idiopathic, while AVN of lunate and scaphoid is usually idiopathic. The secondary osteoarthritis occurs early in patients of AVNC, while secondary osteoarthritis is very late in AVN of lunate and scaphoid. The peculiar types of blood supply of lunate, scaphoid, and capitate make them prone for AVN. There are three main variants of blood supply to capitate, but in all the variants, it is concurrent that the proximal pole of capitate draws its supply in a retrograde intraosseous fashion; hence, any breakage through the capitate made the proximal pole more prone to devascularization. ²

Patients present with varying history, major trauma to the hand that was managed conservatively at the time of the incident, has been a common finding. Symptoms at presentation are pain in the wrist with or without swelling, stiffness in movement, and loss of motion, which is not resolved with adequate rest and analgesia. The presentation of the patient is usually long as it is slow progress pathology. Etiology is a direct trauma or repetitive microtrauma to the wrist or it can be considered to be idiopathic in origin. Medical condition like gout, ligament instability, hematological disorders, systemic lupus erythematosus, and Gaucher's disease has a contributing effect, along with a history of local or systemic steroid use, smoking, and alcoholism. ³

Initial radiographs show sclerosis of the capitate; the collapse of the capitate head occurs early leading to decrease in the midcarpal joint space. The diagnosis is confirmed by MRI, which has a sensitivity of 95% and can show changes before radiographs. Milliez et al had given descriptive classification of AVN capitate based on radiological appearance into type 1 (proximal pole affected), type 2 (distal body affected), and type 3 (entire capitate affected). ⁴

The treatment of AVNC depends on various factors like (1) status of the cartilage of the capitate head, capitate facet of lunate, and capitular articular surface of the scaphoid (2) collapse of the subchondral bone of the capitate (3) patient's choice after being informed about all the procedures. In the presence of good cartilage surfaces of the head of the capitate, capitate facet of lunate and capitular articular surface of the scaphoid; preservation of the capitate, preservation of the mid-carpal space is the primary goal.

Revascularization procedures are performed. Vascularized bone grafting from the radial head has been attempted by Hattori et al. ⁵ If there is subchondral cyst formation, then curettage of the capitate and filling it with autogenous bone graft from iliac crest is a good option. If there is collapse of the capitate bone or articular cartilage of the capitate head is involved, but the articular surfaces of lunate and scaphoid are intact, then this scenario gives a window for the mid-carpal joint preserving procedures. The midcarpal joint procedures preserve better range of motion of the wrist and have shown good mid-term results ( Table 1 ).

Table 1. The different studies regarding the mid-carpal joint sparing procedures have been mentioned in detail.

S. no.	Study	Year	Name of the procedure	Follow-up duration	Outcome	Comments
1	Ansari et al (this report)	2020	Excision carpal head with capito-hamate fusion and ECRL tendon interposition	1.5 y	VAS: Quick DASH: Result:	Good outcome reported at 1 year
2	Shimizu et al 11	2015	Excision carpal head with lunate facet (arthroscopic)	1–2 y	VAS: 0–3 Quick DASH: 8–24 PRWE: 3–38 Result: good to excellent	The articular facet for the capitate was removed. The articular facet for the scaphoid and hamate was preserved. The short-term results at 1 year were good. There was adequate pain relief and improved range of motion of the wrist and grip strength.
3.	Dereudre et al 10	2010	Pyrocarbon resurfacing capitate	3 y	VAS: 2/10 Good	Subluxation of the prosthesis was seen but no clinical symptoms. There was no carpal collapse and the patient was asymptomatic. There was mild decrease in the extension of the wrist, which did not affect the daily activities of the patient. The authors suggested that the four corner fusion may be performed if the procedure fails.
4.	DeSantis 9	2004	Arthroplasty capitate	2 y	VAS not measures; little pain mentioned Result: good	The report is about the physiotherapy used in preoperative and postoperative period of AVN capitate. The type of implant is not mentioned and the radiographs have not been included as it was not the primary goal of the report writing.
5.	Milliez et al 4	1991	Excision and silicone spacer interposition	11 y	Result: moderate to good	He described three cases; in one case, the resection and Swanson silicone implant was placed. The patient went on to join high-level athletic activities. After 11 years, the patient has some pain and osteolysis around the silicone implant was visible. In two other cases, intercarpal arthrodesis was done.
6.	Lapinsky and Mack 8	1992	Excision and spacing with toe extensor tendon from fourth toe	6 mo	Converted to total wrist fusion	The primary procedure was not found to be successful. The immediate postoperative radiographs and radiographs before the wrist arthrodesis were not available in the report. It is difficult to know the reason of failure. It may be continued carpal collapse, AVN of remaining capitate bone, or arthritic changes in the radio-carpal joint.
7.	Gadzaly 7	1983	Excision and silicone spacer interposition	Not mentioned	No pain Result: good	Although the length of follow-up was not mentioned, the patient resumed business activates at 12 weeks. The authors suggested a modification in the ulnar head prosthesis (Silastic-spacer, Design Swanson) as the ulnar head prosthesis was larger to be used as capitate head. The Kessler spacer was also considered large.
8.	Kimmel and O'Brien 6	1982	Excision and spacing with palmaris longus	10 mo	Mild pain Result: moderate	The patient was a typist and she returned to her job after surgery satisfactorily.

Abbreviations: AVN, avascular necrosis; DASH, disability of the arm, shoulder, and hand; ECRL, extensor carpi radialis longus; PRWE, patient-rated wrist evaluation; VAS, visual analog scale.

Note: The critical comments have been added to analyze these studies further.

In the subsequent discussion, we will focus around the previous published studies for the MCJS procedures. Kimmel et al did excision of the capitate and spacing with palmaris longus. ⁶ At 10-month follow-up, the patient performed well. The patient was a typist and she returned to her job after surgery satisfactorily. Gadzaly did excision of the proximal capitate and silicone spacer interposition. ⁷ Although the length of follow-up was not mentioned, the patient resumed business activities at 12 weeks. The authors suggested a modification in the ulnar head prosthesis (Silastic-spacer, Design Swanson) as the ulnar head prosthesis was larger to be used as capitate head. The Kessler spacer was also considered large. In the hands of Lapinsky et al, excision and spacing with toe extensor tendon from fourth toe was not found to be successful. ⁸ The authors have to perform wrist arthrodesis at 6 months. The immediate postoperative radiographs and the radiographs before the wrist arthrodesis were not available in the report. It is difficult to know the reason of failure. It may be continued carpal collapse, AVN of remaining capitate bone or arthritic changes in the radiocarpal joint. Milliez et al described three cases; in one case, the resection and Swanson silicone Implant was placed. ⁴ The patient went on to join high-level athletic activities. After 11 years, the patient had some pain and osteolysis around the silicone implant was visible. In two other cases, intercarpal arthrodesis was done. Milliez et al also reviewed literature of AVNC and described the classification system as described above. DeSantis et al described about a case of capitate arthroplasty in patients of AVNC. ⁹ The report was about the physiotherapy used in preoperative and postoperative period of AVNC. The type of implant was not mentioned, and the radiographs were not included in the report as it was not the primary goal of writing the report.

Pyrocarbon resurfacing of the capitate for AVNC has been described. ¹⁰ At 3-year follow-up, the visual analog score for pain was 2/10 and the function was good. Subluxation of the prosthesis was seen, but there were no clinical symptoms. There was no carpal collapse and the patient was asymptomatic. There was mild decrease in the extension of the wrist, which did not affect the daily activities of the patient. The authors suggested that the four corner fusion may be performed if the procedure fails. Shimizu et al described arthroscopic removal of the lunate facet of the head of the capitate. ¹¹ The articular facet for the scaphoid and hamate was preserved. The short-term results at an average of 1 year (range = 1–2 years) were good. There was adequate pain relief (VAS: 0–3), improved range of motion of the wrist and grip strength. The Quick DASH scores ranged 8 to 24. The results were good to excellent. In our case, there has been adequate pain relief at 1-year follow-up with good functional outcome scores. We performed the capito-hamate fusion also, as we postulated that the hemi-resection of the capitate head leads to increased shear forces between the capitate and hamate. This increase in shear forces may give rise to pain and it may be a predisposing factor for the carpal collapse. This fusion may also give rise to increased force transmission through the hamate, and hence, the patient was placed for a follow-up to look for hamate impaction syndromes. At 1-year follow-up, there has been no such issue with the patient.

The intercarpal fusion procedure or four corner procedures can be performed as a primary procedure after the patient is duly informed that the procedures are final in nature, but these have inherent limitation of the decreased in the range of motion of the wrist. On the contrary, even if the MCJS procedures fail, the option of intercarpal fusion or four corner fusion is always open and preserved. Here, many patients will choose MCJS procedures if they are well informed about every surgical option. The age of the patient may be a factor in decision-making as AVNC is usually seen in young adults. MCJS procedures may be time-buying procedures till arthrodesis is performed.

Conclusion

Even though capitate has a relatively safer anatomical location, AVNC should be considered in patients presenting with chronic wrist pain. MRI should be used for early diagnosis. The stage and classification system helps in the management of the AVNC. Wrist arthroscopy is an essential adjunct for most of the wrist procedures and it helps in assessment of the articular surfaces of the different carpal bones. The synovectomy can be performed more precisely with wrist arthroscopy tools. MCJS procedures can be performed with good mid-term clinical results.

Funding Statement

Funding None.